Publisher: Elsevier   (Total: 3161 journals)

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Showing 1 - 200 of 3161 Journals sorted alphabetically
Academic Pediatrics     Hybrid Journal   (Followers: 39, SJR: 1.655, CiteScore: 2)
Academic Radiology     Hybrid Journal   (Followers: 26, SJR: 1.015, CiteScore: 2)
Accident Analysis & Prevention     Partially Free   (Followers: 106, SJR: 1.462, CiteScore: 3)
Accounting Forum     Hybrid Journal   (Followers: 28, SJR: 0.932, CiteScore: 2)
Accounting, Organizations and Society     Hybrid Journal   (Followers: 44, SJR: 1.771, CiteScore: 3)
Achievements in the Life Sciences     Open Access   (Followers: 7)
Acta Anaesthesiologica Taiwanica     Open Access   (Followers: 6)
Acta Astronautica     Hybrid Journal   (Followers: 447, SJR: 0.758, CiteScore: 2)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 2)
Acta Biomaterialia     Hybrid Journal   (Followers: 30, SJR: 1.967, CiteScore: 7)
Acta Colombiana de Cuidado Intensivo     Full-text available via subscription   (Followers: 3)
Acta de Investigación Psicológica     Open Access   (Followers: 2)
Acta Ecologica Sinica     Open Access   (Followers: 12, SJR: 0.18, CiteScore: 1)
Acta Histochemica     Hybrid Journal   (Followers: 5, SJR: 0.661, CiteScore: 2)
Acta Materialia     Hybrid Journal   (Followers: 325, SJR: 3.263, CiteScore: 6)
Acta Mathematica Scientia     Full-text available via subscription   (Followers: 5, SJR: 0.504, CiteScore: 1)
Acta Mechanica Solida Sinica     Full-text available via subscription   (Followers: 9, SJR: 0.542, CiteScore: 1)
Acta Oecologica     Hybrid Journal   (Followers: 12, SJR: 0.834, CiteScore: 2)
Acta Otorrinolaringologica (English Edition)     Full-text available via subscription  
Acta Otorrinolaringológica Española     Full-text available via subscription   (Followers: 2, SJR: 0.307, CiteScore: 0)
Acta Pharmaceutica Sinica B     Open Access   (Followers: 2, SJR: 1.793, CiteScore: 6)
Acta Psychologica     Hybrid Journal   (Followers: 26, SJR: 1.331, CiteScore: 2)
Acta Sociológica     Open Access   (Followers: 1)
Acta Tropica     Hybrid Journal   (Followers: 6, SJR: 1.052, CiteScore: 2)
Acta Urológica Portuguesa     Open Access   (Followers: 1)
Actas Dermo-Sifiliograficas     Full-text available via subscription   (Followers: 3, SJR: 0.374, CiteScore: 1)
Actas Dermo-Sifiliográficas (English Edition)     Full-text available via subscription   (Followers: 2)
Actas Urológicas Españolas     Full-text available via subscription   (Followers: 3, SJR: 0.344, CiteScore: 1)
Actas Urológicas Españolas (English Edition)     Full-text available via subscription   (Followers: 1)
Actualites Pharmaceutiques     Full-text available via subscription   (Followers: 7, SJR: 0.19, CiteScore: 0)
Actualites Pharmaceutiques Hospitalieres     Full-text available via subscription   (Followers: 3)
Acupuncture and Related Therapies     Hybrid Journal   (Followers: 8)
Acute Pain     Full-text available via subscription   (Followers: 15, SJR: 2.671, CiteScore: 5)
Ad Hoc Networks     Hybrid Journal   (Followers: 11, SJR: 0.53, CiteScore: 4)
Addictive Behaviors     Hybrid Journal   (Followers: 18, SJR: 1.29, CiteScore: 3)
Addictive Behaviors Reports     Open Access   (Followers: 9, SJR: 0.755, CiteScore: 2)
Additive Manufacturing     Hybrid Journal   (Followers: 13, SJR: 2.611, CiteScore: 8)
Additives for Polymers     Full-text available via subscription   (Followers: 22)
Advanced Drug Delivery Reviews     Hybrid Journal   (Followers: 190, SJR: 4.09, CiteScore: 13)
Advanced Engineering Informatics     Hybrid Journal   (Followers: 13, SJR: 1.167, CiteScore: 4)
Advanced Powder Technology     Hybrid Journal   (Followers: 17, SJR: 0.694, CiteScore: 3)
Advances in Accounting     Hybrid Journal   (Followers: 9, SJR: 0.277, CiteScore: 1)
Advances in Agronomy     Full-text available via subscription   (Followers: 17, SJR: 2.384, CiteScore: 5)
Advances in Anesthesia     Full-text available via subscription   (Followers: 30, SJR: 0.126, CiteScore: 0)
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 2)
Advances in Applied Mathematics     Full-text available via subscription   (Followers: 12, SJR: 0.992, CiteScore: 1)
Advances in Applied Mechanics     Full-text available via subscription   (Followers: 12, SJR: 1.551, CiteScore: 4)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 24, SJR: 2.089, CiteScore: 5)
Advances In Atomic, Molecular, and Optical Physics     Full-text available via subscription   (Followers: 15, SJR: 0.572, CiteScore: 2)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4, SJR: 2.61, CiteScore: 7)
Advances in Botanical Research     Full-text available via subscription   (Followers: 1, SJR: 0.686, CiteScore: 2)
Advances in Cancer Research     Full-text available via subscription   (Followers: 35, SJR: 3.043, CiteScore: 6)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 9, SJR: 1.453, CiteScore: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5, SJR: 1.992, CiteScore: 5)
Advances in Cell Aging and Gerontology     Full-text available via subscription   (Followers: 5)
Advances in Cellular and Molecular Biology of Membranes and Organelles     Full-text available via subscription   (Followers: 14)
Advances in Chemical Engineering     Full-text available via subscription   (Followers: 29, SJR: 0.156, CiteScore: 1)
Advances in Child Development and Behavior     Full-text available via subscription   (Followers: 11, SJR: 0.713, CiteScore: 1)
Advances in Chronic Kidney Disease     Full-text available via subscription   (Followers: 11, SJR: 1.316, CiteScore: 2)
Advances in Clinical Chemistry     Full-text available via subscription   (Followers: 26, SJR: 1.562, CiteScore: 3)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 21, SJR: 1.977, CiteScore: 8)
Advances in Computers     Full-text available via subscription   (Followers: 14, SJR: 0.205, CiteScore: 1)
Advances in Dermatology     Full-text available via subscription   (Followers: 16)
Advances in Developmental Biology     Full-text available via subscription   (Followers: 14)
Advances in Digestive Medicine     Open Access   (Followers: 13)
Advances in DNA Sequence-Specific Agents     Full-text available via subscription   (Followers: 7)
Advances in Drug Research     Full-text available via subscription   (Followers: 26)
Advances in Ecological Research     Full-text available via subscription   (Followers: 45, SJR: 2.524, CiteScore: 4)
Advances in Engineering Software     Hybrid Journal   (Followers: 30, SJR: 1.159, CiteScore: 4)
Advances in Experimental Biology     Full-text available via subscription   (Followers: 9)
Advances in Experimental Social Psychology     Full-text available via subscription   (Followers: 51, SJR: 5.39, CiteScore: 8)
Advances in Exploration Geophysics     Full-text available via subscription   (Followers: 2)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 9)
Advances in Food and Nutrition Research     Full-text available via subscription   (Followers: 68, SJR: 0.591, CiteScore: 2)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 17)
Advances in Genetics     Full-text available via subscription   (Followers: 21, SJR: 1.354, CiteScore: 4)
Advances in Genome Biology     Full-text available via subscription   (Followers: 12, SJR: 12.74, CiteScore: 13)
Advances in Geophysics     Full-text available via subscription   (Followers: 8, SJR: 1.193, CiteScore: 3)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 26, SJR: 0.368, CiteScore: 1)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 11, SJR: 0.749, CiteScore: 3)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 26)
Advances in Imaging and Electron Physics     Full-text available via subscription   (Followers: 3, SJR: 0.193, CiteScore: 0)
Advances in Immunology     Full-text available via subscription   (Followers: 37, SJR: 4.433, CiteScore: 6)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 10, SJR: 1.163, CiteScore: 2)
Advances in Insect Physiology     Full-text available via subscription   (Followers: 2, SJR: 1.938, CiteScore: 3)
Advances in Integrative Medicine     Hybrid Journal   (Followers: 6, SJR: 0.176, CiteScore: 0)
Advances in Intl. Accounting     Full-text available via subscription   (Followers: 3)
Advances in Life Course Research     Hybrid Journal   (Followers: 9, SJR: 0.682, CiteScore: 2)
Advances in Lipobiology     Full-text available via subscription   (Followers: 1)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 8)
Advances in Marine Biology     Full-text available via subscription   (Followers: 21, SJR: 0.88, CiteScore: 2)
Advances in Mathematics     Full-text available via subscription   (Followers: 17, SJR: 3.027, CiteScore: 2)
Advances in Medical Sciences     Hybrid Journal   (Followers: 9, SJR: 0.694, CiteScore: 2)
Advances in Medicinal Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Microbial Physiology     Full-text available via subscription   (Followers: 5, SJR: 1.158, CiteScore: 3)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 26)
Advances in Molecular and Cellular Endocrinology     Full-text available via subscription   (Followers: 8)
Advances in Molecular Toxicology     Full-text available via subscription   (Followers: 7, SJR: 0.182, CiteScore: 0)
Advances in Nanoporous Materials     Full-text available via subscription   (Followers: 5)
Advances in Oncobiology     Full-text available via subscription   (Followers: 2)
Advances in Organ Biology     Full-text available via subscription   (Followers: 2)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 18, SJR: 1.875, CiteScore: 4)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7, SJR: 0.174, CiteScore: 0)
Advances in Parasitology     Full-text available via subscription   (Followers: 6, SJR: 1.579, CiteScore: 4)
Advances in Pediatrics     Full-text available via subscription   (Followers: 27, SJR: 0.461, CiteScore: 1)
Advances in Pharmaceutical Sciences     Full-text available via subscription   (Followers: 19)
Advances in Pharmacology     Full-text available via subscription   (Followers: 17, SJR: 1.536, CiteScore: 3)
Advances in Physical Organic Chemistry     Full-text available via subscription   (Followers: 10, SJR: 0.574, CiteScore: 1)
Advances in Phytomedicine     Full-text available via subscription  
Advances in Planar Lipid Bilayers and Liposomes     Full-text available via subscription   (Followers: 3, SJR: 0.109, CiteScore: 1)
Advances in Plant Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 11)
Advances in Plant Pathology     Full-text available via subscription   (Followers: 6)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 19)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20, SJR: 0.791, CiteScore: 2)
Advances in Psychology     Full-text available via subscription   (Followers: 69)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 7, SJR: 0.371, CiteScore: 1)
Advances in Radiation Oncology     Open Access   (Followers: 3, SJR: 0.263, CiteScore: 1)
Advances in Small Animal Medicine and Surgery     Hybrid Journal   (Followers: 3, SJR: 0.101, CiteScore: 0)
Advances in Space Biology and Medicine     Full-text available via subscription   (Followers: 7)
Advances in Space Research     Full-text available via subscription   (Followers: 430, SJR: 0.569, CiteScore: 2)
Advances in Structural Biology     Full-text available via subscription   (Followers: 6)
Advances in Surgery     Full-text available via subscription   (Followers: 13, SJR: 0.555, CiteScore: 2)
Advances in the Study of Behavior     Full-text available via subscription   (Followers: 37, SJR: 2.208, CiteScore: 4)
Advances in Veterinary Medicine     Full-text available via subscription   (Followers: 20)
Advances in Veterinary Science and Comparative Medicine     Full-text available via subscription   (Followers: 15)
Advances in Virus Research     Full-text available via subscription   (Followers: 6, SJR: 2.262, CiteScore: 5)
Advances in Water Resources     Hybrid Journal   (Followers: 57, SJR: 1.551, CiteScore: 3)
Aeolian Research     Hybrid Journal   (Followers: 6, SJR: 1.117, CiteScore: 3)
Aerospace Science and Technology     Hybrid Journal   (Followers: 396, SJR: 0.796, CiteScore: 3)
AEU - Intl. J. of Electronics and Communications     Hybrid Journal   (Followers: 8, SJR: 0.42, CiteScore: 2)
African J. of Emergency Medicine     Open Access   (Followers: 6, SJR: 0.296, CiteScore: 0)
Ageing Research Reviews     Hybrid Journal   (Followers: 12, SJR: 3.671, CiteScore: 9)
Aggression and Violent Behavior     Hybrid Journal   (Followers: 491, SJR: 1.238, CiteScore: 3)
Agri Gene     Hybrid Journal   (Followers: 1, SJR: 0.13, CiteScore: 0)
Agricultural and Forest Meteorology     Hybrid Journal   (Followers: 18, SJR: 1.818, CiteScore: 5)
Agricultural Systems     Hybrid Journal   (Followers: 32, SJR: 1.156, CiteScore: 4)
Agricultural Water Management     Hybrid Journal   (Followers: 47, SJR: 1.272, CiteScore: 3)
Agriculture and Agricultural Science Procedia     Open Access   (Followers: 4)
Agriculture and Natural Resources     Open Access   (Followers: 3)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 58, SJR: 1.747, CiteScore: 4)
Ain Shams Engineering J.     Open Access   (Followers: 5, SJR: 0.589, CiteScore: 3)
Air Medical J.     Hybrid Journal   (Followers: 8, SJR: 0.26, CiteScore: 0)
AKCE Intl. J. of Graphs and Combinatorics     Open Access   (SJR: 0.19, CiteScore: 0)
Alcohol     Hybrid Journal   (Followers: 12, SJR: 1.153, CiteScore: 3)
Alcoholism and Drug Addiction     Open Access   (Followers: 12)
Alergologia Polska : Polish J. of Allergology     Full-text available via subscription   (Followers: 1)
Alexandria Engineering J.     Open Access   (Followers: 2, SJR: 0.604, CiteScore: 3)
Alexandria J. of Medicine     Open Access   (Followers: 1, SJR: 0.191, CiteScore: 1)
Algal Research     Partially Free   (Followers: 11, SJR: 1.142, CiteScore: 4)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
Allergologia et Immunopathologia     Full-text available via subscription   (Followers: 1, SJR: 0.504, CiteScore: 1)
Allergology Intl.     Open Access   (Followers: 5, SJR: 1.148, CiteScore: 2)
Alpha Omegan     Full-text available via subscription   (SJR: 3.521, CiteScore: 6)
ALTER - European J. of Disability Research / Revue Européenne de Recherche sur le Handicap     Full-text available via subscription   (Followers: 11, SJR: 0.201, CiteScore: 1)
Alzheimer's & Dementia     Hybrid Journal   (Followers: 55, SJR: 4.66, CiteScore: 10)
Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring     Open Access   (Followers: 6, SJR: 1.796, CiteScore: 4)
Alzheimer's & Dementia: Translational Research & Clinical Interventions     Open Access   (Followers: 6, SJR: 1.108, CiteScore: 3)
Ambulatory Pediatrics     Hybrid Journal   (Followers: 5)
American Heart J.     Hybrid Journal   (Followers: 58, SJR: 3.267, CiteScore: 4)
American J. of Cardiology     Hybrid Journal   (Followers: 67, SJR: 1.93, CiteScore: 3)
American J. of Emergency Medicine     Hybrid Journal   (Followers: 48, SJR: 0.604, CiteScore: 1)
American J. of Geriatric Pharmacotherapy     Full-text available via subscription   (Followers: 13)
American J. of Geriatric Psychiatry     Hybrid Journal   (Followers: 15, SJR: 1.524, CiteScore: 3)
American J. of Human Genetics     Hybrid Journal   (Followers: 40, SJR: 7.45, CiteScore: 8)
American J. of Infection Control     Hybrid Journal   (Followers: 29, SJR: 1.062, CiteScore: 2)
American J. of Kidney Diseases     Hybrid Journal   (Followers: 37, SJR: 2.973, CiteScore: 4)
American J. of Medicine     Hybrid Journal   (Followers: 50)
American J. of Medicine Supplements     Full-text available via subscription   (Followers: 3, SJR: 1.967, CiteScore: 2)
American J. of Obstetrics and Gynecology     Hybrid Journal   (Followers: 266, SJR: 2.7, CiteScore: 4)
American J. of Ophthalmology     Hybrid Journal   (Followers: 67, SJR: 3.184, CiteScore: 4)
American J. of Ophthalmology Case Reports     Open Access   (Followers: 5, SJR: 0.265, CiteScore: 0)
American J. of Orthodontics and Dentofacial Orthopedics     Full-text available via subscription   (Followers: 6, SJR: 1.289, CiteScore: 1)
American J. of Otolaryngology     Hybrid Journal   (Followers: 25, SJR: 0.59, CiteScore: 1)
American J. of Pathology     Hybrid Journal   (Followers: 32, SJR: 2.139, CiteScore: 4)
American J. of Preventive Medicine     Hybrid Journal   (Followers: 30, SJR: 2.164, CiteScore: 4)
American J. of Surgery     Hybrid Journal   (Followers: 39, SJR: 1.141, CiteScore: 2)
American J. of the Medical Sciences     Hybrid Journal   (Followers: 12, SJR: 0.767, CiteScore: 1)
Ampersand : An Intl. J. of General and Applied Linguistics     Open Access   (Followers: 7)
Anaerobe     Hybrid Journal   (Followers: 4, SJR: 1.144, CiteScore: 3)
Anaesthesia & Intensive Care Medicine     Full-text available via subscription   (Followers: 67, SJR: 0.138, CiteScore: 0)
Anaesthesia Critical Care & Pain Medicine     Full-text available via subscription   (Followers: 25, SJR: 0.411, CiteScore: 1)
Anales de Cirugia Vascular     Full-text available via subscription   (Followers: 1)
Anales de Pediatría     Full-text available via subscription   (Followers: 3, SJR: 0.277, CiteScore: 0)
Anales de Pediatría (English Edition)     Full-text available via subscription  
Anales de Pediatría Continuada     Full-text available via subscription  
Analytic Methods in Accident Research     Hybrid Journal   (Followers: 6, SJR: 4.849, CiteScore: 10)
Analytica Chimica Acta     Hybrid Journal   (Followers: 44, SJR: 1.512, CiteScore: 5)
Analytica Chimica Acta : X     Open Access  
Analytical Biochemistry     Hybrid Journal   (Followers: 214, SJR: 0.633, CiteScore: 2)
Analytical Chemistry Research     Open Access   (Followers: 13, SJR: 0.411, CiteScore: 2)
Analytical Spectroscopy Library     Full-text available via subscription   (Followers: 14)
Anesthésie & Réanimation     Full-text available via subscription   (Followers: 2)
Anesthesiology Clinics     Full-text available via subscription   (Followers: 25, SJR: 0.683, CiteScore: 2)
Angiología     Full-text available via subscription   (SJR: 0.121, CiteScore: 0)
Angiologia e Cirurgia Vascular     Open Access   (Followers: 1, SJR: 0.111, CiteScore: 0)
Animal Behaviour     Hybrid Journal   (Followers: 239, SJR: 1.58, CiteScore: 3)
Animal Feed Science and Technology     Hybrid Journal   (Followers: 8, SJR: 0.937, CiteScore: 2)
Animal Reproduction Science     Hybrid Journal   (Followers: 7, SJR: 0.704, CiteScore: 2)
Annales d'Endocrinologie     Full-text available via subscription   (Followers: 3, SJR: 0.451, CiteScore: 1)

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Similar Journals
Journal Cover
AEU - International Journal of Electronics and Communications
Journal Prestige (SJR): 0.42
Citation Impact (citeScore): 2
Number of Followers: 8  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1434-8411 - ISSN (Online) 1618-0399
Published by Elsevier Homepage  [3161 journals]
  • Maximizing the Efficiency of Wireless Power Transfer Systems with an
           Optimal Duty Cycle Operation
    • Abstract: Publication date: Available online 21 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Seyit Ahmet Sis, Hakan AkcaAbstractIn a typical high-power inductive wireless power transfer (WPT) system, AC signal, which drives the coupled resonant inductors (couplers), is produced by a half- or full-bridge inverter. However, the output voltage of an inverter is not a pure sinusoidal but a square wave with quite a few harmonics. Harmonics are expected to reduce active power transfer efficiency (APTE) due to high reactive power accumulation at the input to the resonant couplers. In this paper, WPT system efficiency is analyzed by introducing the harmonics of the voltage waveform of a typical inverter circuit in to an analytical model of the WPT system for the first time. In this regard, total harmonic distortion (THD) and harmonic content of the waveform, as well as the APTE of the system are all simulated as a function of duty cycle using an analytic model. Simulation results show that the THD of the source voltage waveform can be minimized with a duty cycle of 75%. Hence the reactive power at the input of the system is also minimized, increasing the APTE of the system in this duty cycle. An experimental wireless power transfer system is implemented to verify the aforementioned simulation based observation. The measured APTE is increased to a maximum of 94.5% from approximately 88.5% by simply reducing the duty cycle from 100% to 75%. The output power delivered to the load, on the other hand, decreases with this reduction in the duty cycle, if DC bus voltage stays constant. This trade of between efficiency and the delivered power to the load is analyzed in two wireless charging scenarios with different power and efficiency levels. We believe that the findings reported in this work would potentially lead researchers develop novel inverter structures to not only use for increasing power but also the efficiency of WPT systems.
       
  • Taguchi DOE and ANOVA: A Systematic perspective for performance
           optimization of Cross-Coupled Channel Length Modulation OTA
    • Abstract: Publication date: Available online 21 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Tangudu Bharat Kumar, Apurbaranjan Panda, Gaurav Kumar Sharma, Arun Kishor Johar, Sougata Kumar Kar, Dharmendar BoolchandaniAbstractThis work is a demonstration of circuit optimization using Taguchi Design of Experiments. Cross coupled channel length modulation OTA has been considered for optimization. This optimization technique uses the concept of Signal to Noise Ratio (SNR) and Analysis of Variance (ANOVA) to predict which independent variable controls the performance of the circuit. Bias current, channel width and channel length of input transistors have been chosen to optimize the circuit performance. The obtained parameters for optimum performance from this method are verified by simulating the circuit using UMC 0.18μm CMOS technology. The simulation results obtained are pretty close to the predicted solution from ANOVA. From simulation results, transconductance, power consumption, percentage total harmonic distortion, linearity range and DC gain of the proposed OTA are 24.63nS, 1.026μW, 0.347%, 1.09V, and 54.88dB respectively. The proposed optimized circuit, therefore, can be utilized in biomedical applications.
       
  • Metasurface: Changing Polarization from Linear to Circular for Airborne
           Antenna
    • Abstract: Publication date: Available online 20 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Zixiang Lin, Ruipeng Liu, Xia Wang, Hongxing Zheng, Mengjun Wang, Erping LiAbstractTo implement the circular polarization antenna on the airborne electronic platform, a new technique of polarization change is investigated in this paper. A metasurface structure consisting of a 5×5 array has been designed. Each unit of the metasurface structure is a stack circular ring, and two orthogonal dipoles in a ring can convert the linear polarization wave into circular one. An ultra-wideband (UWB) antenna is designed combining with the metasurface structure. To filter some interference signals from special frequency bands such as WLAN and WiMAX, dual notched-bands have been designed on the UWB antenna. Therefore, dual circular polarization radiation character at two bands of 4 GHz - 7.9 GHz and 8.1 GHz - 12.4 GHz is achieved. The antenna with metasurface is operated at 2.6 GHz - 13.6 GHz excepting for two notched-bands of 3.15 GHz – 4.3 GHz and 5.5 GHz - 5.75 GHz. Fabricated sample has been verified by experiment, and the results indicate that the design is available.
       
  • Using Moment Generating Function for Performance Analysis in
           Non-Regenerative Cooperative Relay Networks with Max-Min Relay Selection
    • Abstract: Publication date: Available online 20 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Muhammad Asshad, Adnan Kavak, Kerem Küçük, Sajjad Ahmad KhanAbstractThis study presents the performance analysis of non-regenerative wireless cooperative network over Rayleigh and Weibull fading channels with max-min best relay selection technique. The moment generating function (MGF) of signal-to-noise ratio (SNR) at the destination node is derived using the Weibull fading parameter. Using MGF, we also determine the lower bound value of symbol error rate and outage probability. Analytical and simulation results with regard to outage probability and symbol error rate are given under varying number of relay nodes with max-min relay selection technique to verify the accuracy of the derivation. The results show that increase in the number of relay nodes provides better performance in Rayleigh fading channel when compared to the value of Weibull fading parameter larger than two.
       
  • 1.2V Asymmetric-CCC based sub-3dB NF high IIP3 linearity Wideband
           Balun-LNA
    • Abstract: Publication date: Available online 20 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): K Hari Kishore, Sat Prakash, B VenkataramaniAbstractA CG-CS wideband balun-LNA using asymmetric capacitive cross-coupling (A-CCC) and an auxiliary current reuse amplifier (ACRA) is reported in the literature. It achieves low noise figure (NF) and high gain at the cost of linearity. To improve the linearity, inductive loads are proposed. However, this is at the cost of increase in chip area. To overcome this problem, a balun-LNA using modified complementary derivative superposition and asymmetric CCC-DS techniques for the ACRA and A-CCC block respectively is proposed in this paper. It dispenses with the inductive loads. The balun-LNAs with and without the proposed linearization are implemented in UMC 180nm CMOS technology with a supply of 1.2V and are studied through post-layout simulations. It is found that the proposed LNA has +7.96dBm increase in average IIP3 compared to the LNA without the proposed linearization. It achieves an average IIP3 of +5.49dBm with a peak gain of 24.2dB and minimum NF of 2.18dB over the bandwidth of 1–3 GHz. The proposed LNA requires an area of 0.3mm2 and a power of 6.95mW.
       
  • Design of Continuous Mode Doherty Power Amplifiers Using Generalized
           Output Combiner
    • Abstract: Publication date: Available online 20 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Decheng Gan, Weimin Shi, Muhammad Furqan Haider, Gideon NaahAbstractIn this paper, a continuous mode Doherty power amplifier (DPA) working over an octave bandwidth is constructed using a generalized combiner. The generalized combiner provides the PA designers with more freedoms for realizing broadband DPAs. Theoretically, the generalized combiner could expand the working bandwidth of continuous mode DPA. A continuous mode DPA working over 1.2-2.7 GHz (a relative bandwidth of 76.9%) is implemented in this contribution for demonstrating the universality of the generalized combiner. As a demonstrator circuit, the fabricated DPA achieves drain effciencies of 40%-54% and 44%-75% at 6 dB back-off and saturation power levels, respectively. The maximum output power of the fabricated DPA is 42.1-44.2 dBm with a saturation gain of 7.2-11.3 dB over 1.2-2.7 GHz. When the designed DPA is excited by a 20 MHz LTE signal with a peak to average power ratio of 7.04 dB, the fabricated DPA achieves adjacent channel leakage ratios (ACLRs) of -29.5 dBc and -49.5 dBc at 2.4 GHz before and after DPD technique, respectively.
       
  • Realization of Current Mode Universal Shadow Filter
    • Abstract: Publication date: Available online 20 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Divya Singh, Sajal K. PaulAbstractIn this paper, a current-mode universal shadow filter is proposed using a new variant of current differencing transconductance amplifier (CDTA), namely current controlled current differencing cascaded transconductance amplifier (CC-CDCTA) and two capacitors. It realizes three shadow filter functioning; low pass (LPS), high pass (HPS) and band pass (BPS). Furthermore, it is extended to a universal filter by adding one second generation current conveyor (CCII) and CC-CDCTA building blocks. The proposed configuration realizes all the standard responses of a universal shadow filter such as LPS, BPS, HPS, band-reject (BRS), and all pass (APS) simultaneously. It does not use any resistor. The presented shadow filter utilizes the LP and BP outputs of the basic filter in the feedback amplifier to obtain the desired universal shadow filter functionality. The pole frequency (ωos) and quality factor (Qos) of the shadow filter is electronically tunable using the gain of the feedback amplifiers. The ωos and Qos can also be tuned without disturbing each other. It is also found to be suitable for full cascadability. The validation is done using 180 nm technology in Cadence. Experimental verification has also been done using IC AD844, and CA3080 and found satisfactory results.
       
  • Impedance Matching and Efficiency Improvement of a Dual-Band Wireless
           Power Transfer System Using Variable Inductance and Coupling Method
    • Abstract: Publication date: Available online 20 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Amir Fereshtian, Javad GhalibafanAbstractThis paper proposes a dual-band wireless power transfer (DWPT) system which can deliver more power compared to a single-band WPT within the electromagnetic field constraints. Moreover, one of its channels can be applied to increase the data transfer rate compared to a single-band WPT. In this work because of less crosstalk between distinct frequencies, a dual-resonant single-coil is used similarly as a transmitter and receiver. The main challenge in the design of conventional DWPT systems is the simultaneous impedance matching at the different resonant frequencies. In the proposed method, this problem has been solved by varying the coupling factor between the source (load) and the dual-band internal resonator. Moreover, we analytically investigate the influence of the different values of the source(load) inductance on impedance matching. The system equivalent circuit model is presented, and the voltage transfer function and the matching condition for transmitting maximum power are extracted. To evaluate the system performance, the power transfer efficiency is simulated by HFSS software and validated by experimental results. The measurement results show the efficiency of 71% and 56% at frequencies of 6.78 MHz and 13.56 MHz, respectively.
       
  • Design of Compact Dual-Polarized Multiband MIMO Antenna using Near-Field
           for IoT
    • Abstract: Publication date: Available online 20 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Naveen Kumar Maurya, Rajarshi BhattacharyaAbstractThis paper presents the integration of the unlicensed ultra-wideband (UWB) with the existing bands like the 1.9 GHz long‐term‐evolution (LTE) band and 2.4 GHz industrial scientific and medical (ISM) band to cater for the diverse need of the upcoming internet of things (IoT) technology. The designed compact triband antenna has a dimension of 33×18 mm2 (i.e. 0.2λ0×0.11λ0, where λ0 is calculated at 1.89 GHz in the free space). This antenna provides high-quality factor (Q) and narrow-band impedance matching at the 1.9 and 2.4 GHz bands with about 2.9% and 4.7% bandwidth respectively, which is sufficient for those IoT applications, which are supposed to support low data rate communication. Further, the triband antenna is found to be effective for IoT as the hosting effect is within the tolerable range. Finally, multiband polarization diversity antenna is designed having a size of only 33×57.25 mm2 (0.2λ0×0.36λ0) to combat the depolarization effect of signals in the indoor environment. Near-field simulations are carried out to determine the best position/orientation of MIMO elements in order to improve port-to-port isolation and envelope-correlation-coefficient (ECC). The minimum isolation and maximum ECC are found to be 14.2 dB and 0.0471, respectively across all the operating frequency bands.
       
  • Wide Beam Reflector Antenna with Cosecant-Squared Pattern
    • Abstract: Publication date: Available online 19 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Hadi Ahmadabadi, Sadjad Mallahzadeh, Abdorreza TorabiAbstractIn this paper, a reflector antenna with a cosecant-squared and wide beam pattern is presented. The cosecant-squared antennas with different structures were reported to achieve a pencil beam area in azimuth direction but in this paper, a cosecant-squared antenna with a half beam angle of 33˚ was successfully synthesised. Such a wide beam pattern at the azimuth plane provides an appropriate coverage area for detection. A particle swarm optimization algorithm is used to synthesis the reflector surface of the antenna with respect to obtaining the desired cosecant-squared pattern. Tuning and finalizing the antenna structure have been done by using numerical full wave simulation. Finally, the designed antenna has been fabricated and tested in the far-field measurement setup. There is a good agreement between simulation and measurement results.
       
  • Effects of Downscaling on Radiation Performance of Impedance-Matched
           Ultrasmall Antennas
    • Abstract: Publication date: Available online 18 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Vasan Jantarachote, Sitt Tontisirin, Korbinian Schraml, Dirk Heberling, Prayoot Akkaraekthalin, Suramate ChalermwisutkulAbstractThis paper presents design and measurement verification of ultrasmall antennas with 1.16 GHz operating frequency. Two miniaturization techniques were applied including meander line-based near field resonant parasitic (NFRP) element and split ring resonator-based NFRP element. The designs were scaled down in four steps from ka = 0.825 to ka = 0.103 which is the ultimate design goal regarding the size of the antenna. Promising models were fabricated and corresponding results are measured. The gains of the antenna prototypes were compared among different designs and with the theoretical gain limit for different ka values. Promising models from this work can be applied for on-chip antenna design in the future.
       
  • 2-D Analytical Modeling of Drain and Gate-Leakage Currents of Cylindrical
           Gate Asymmetric Halo Doped Dual Material-Junctionless Accumulation Mode
           MOSFET
    • Abstract: Publication date: Available online 18 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Kamalaksha Baral, Prince Kumar Singh, Sanjay Kumar, Ashish Singh, Manas Tripathy, Sweta Chander, Satyabrata JitAbstractThis paper reports a physics-based analytical model for the cylindrical-gate (CG) asymmetric halo doped graded-channel (GC) dual-material (DM) junctionless-accumulation-mode (JAM) MOSFETs by incorporating both the effects of gate material engineering and channel engineering on the device characteristics. Poisson’s equation has been solved using the superposition technique with appropriate boundary conditions. The minimum central potential concept has been used to derive the threshold voltage model. The drain and gate currents have been modeled by including the effects of gate induced drain leakage (GIDL) and gate leakage currents, respectively. The performance parameters of the proposed CG-GCDM JAM MOSFETs have been compared with those of the CG-DM and CG-GC JAM-MOSFETs to show that the proposed structure has enhanced reliability against short channel effects (SCEs), hot carrier effects (HCEs) and various leakage currents (GIDL and gate leakage) for various control-to-screen gate length ratios. The proposed modeled results have been validated by comparing them with numerical data obtained by using a 3D commercial TCAD simulator.
       
  • Flexible and Miniaturized Design of Microstrip Patch Antenna with Improved
           Cross-Polarized Radiation
    • Abstract: Publication date: Available online 17 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): S. Poornima, Koushik Dutta, Halappa Gajera, K.S. Chandrashekar, S. ChandrammaAbstractA simple and miniaturized design of rectangular microstrip patch antenna (RMPA) is presented with improved cross-polarization (XP) purity. This design approach is much more flexible to tune the resonance frequency of the antenna for its optimum performance. A complete design guideline based on theoretical analysis has been provided to estimate the antenna resonance frequency and corresponding resonant mode. The higher-order spurious mode, orthogonal to the co-polarized fields, has been identified as the source of XP radiation. The physical insight into the XP suppression has been thoroughly discussed and successfully applied for an optimum design. An improved antenna configuration has been realized without any perturbation in the radiating patch or the ground plane. Size, gain, and impedance matching of the proposed antenna have also been considered along with the suppression of XP value. This may be applicable to any conventional working RMPA by introducing very small possible changes. As much as 16 dB suppression of XP radiation is realized in the H-plane without affecting the co-polarized peak-gain value of 5.27 dBi. The proposed concept has been experimentally validated using a set of antenna prototypes. Measured results are closely corroborated with the simulated predictions.
       
  • Novel Ultrathin Penta-band Metamaterial Absorber
    • Abstract: Publication date: Available online 14 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Priyanka Garg, Priyanka JainAbstractThis paper presents a novel resonant metamaterial absorber exhibiting five resonant peaks with absorptivity more than 90% in the range from S band to Ku band for radar cross-section reduction and other FCC-airborne applications. The structure is designed on a low cost FR-4 substrate with 1 mm thickness which is equivalent to λ/17.75 where λ is the wavelength corresponding to maximum resonant frequency of absorption, showing its ultrathin nature. The fourfold symmetry of the design results in polarization insensitivity and provides an angular stability up to 60° of incident angle. The multiband characteristics are obtained by combining three different geometries in a single structure. Performance of the absorber is studied in terms of absorptivity, material parameters, normalized impedance, polarization insensitivity and oblique incidence. Finally, the design is fabricated on a 200×200mm2 FR-4 substrate and measurements are performed.
       
  • Design and Implementation of Evanescent Mode Waveguide Filters Using
           Dielectrics and Additive Manufacturing Techniques
    • Abstract: Publication date: Available online 13 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Alejandro Pons-Abenza, José-María García-Barceló, Antonio Romera-Pérez, Alejandro Alvarez-Melcon, Fernando D. Quesada-Pereira, Juan Hinojosa-Jiménez, Marco Guglielmi, Vicente E. Boria Esbert, Lara Arche-AndradasAbstractIn this contribution, we describe the design of bandpass filters using evanescent mode wavegudies and dielectric resonators implemented with additive manufacturing techniques. Two C-band Chebyshev evanescent mode waveguide filters of order five have been designed using a low cost commercial dielectric material (ABSplus), widely used by Fused Deposition Modeling (FDM) 3D printers. The housings of the filters have been manufactured using traditional computer numerical control (CNC) machining techniques. Practical manufacturing considerations are also discussed, including the integration of dielectric and metallic parts. We first discuss two breadboards using two different resonator geometries. We then demonstrate how different transfer functions can be easily implemented by changing the 3D printed parts in the same metallic housing. Breadboards show fractional bandwidths between 3% and 4.6% with return losses better than RL=18 dB, and spurious free ranges of SFR=1 GHz. Insertion losses are better than IL=4.3 dB. Even though dielectric losses from the plastic material are shown to be high, the measured results are quite satisfactory, thereby clearly showing that this strategy maybe useful for the fast production of low cost microwave filters implementing complex geometries.
       
  • Design and Analysis of Ultra High-Speed Low-Power Double Tail Dynamic
           Comparator using Charge Sharing Scheme
    • Abstract: Publication date: Available online 12 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Vikrant Varshney, Rajendra Kumar NagariaAbstractIn this paper, an ultra high speed dynamic comparator is presented. The PMOS pass transistors are used in the latch and pre-amplifier stage of the comparator. At the regeneration phase, the latch is activated faster with sufficient preamplification gain and very less power consumption. Meanwhile, a cross-coupled set up of NMOS transistors in latch stage enhances the gain and speed. Unlike the previous reported comparator, the proposed dynamic circuit avoids the extra power consumption as well as delay, and establishes the optimum offset and kickback noise. The benefits in delay and power are verified with the help of analytical expressions, meticulous Monte Carlo simulations and process corner analysis in CADENCE SPECTRE at 90nm CMOS technology. The simulation results validate that the proposed structure provides the about 2.5 times better speed and minimizes the power consumption by 3 times in comparison to hybrid double tail dynamic comparator with only 0.348fJ/conv. energy per conversion. Moreover, it provides 2.44mV offset with optimum kickback noise and area.
       
  • Electrically Tunable Mantle Cloaking Utilizing Graphene Metasurface for
           Oblique Incidence
    • Abstract: Publication date: Available online 10 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Zahra Hamzavi-Zarghani, Alireza Y. ahaghi, Ladislau M. atekovitsAbstractAn analytic formulation to achieve mantle cloaking of a dielectric cylinder using scattering cancellation method for TMz polarized oblique incidence is presented. To obtain this goal, a closed form expression for the required surface impedance of the covering metasurface is derived. By properly tuning the chemical potential of graphene, its surface impedance is adjusted for the invisibility of the considered cylinder for arbitrary angles of the impinging plane wave. The scattering width reduction of 15.7dB and 21.27dB is obtained with 3-dB bandwidth of 18.7% and 10.6% at 1 THz and 1.5 THz, respectively for the incident angle of 60 degrees. Furthermore, by optimizing the surface impedance of graphene, finite cylinders can also be cloaked. The results indicate 11.4dB and 13.5dB radar cross section (RCS) reduction with 30% and 22% 3-dB bandwidth for the incident angles of 45â—¦ and 80â—¦ degrees, respectively. Full-wave simulations verify the analytical results. The effect of the cloaking is examined by comparing the input impedance of a pyramidal horn antenna when it is loaded with an array of bear and cloaked cylinders positioned in the aperture.
       
  • Complex dynamic behaviors in a new Colpitts oscillator topology based on a
           voltage comparator
    • Abstract: Publication date: Available online 8 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): M. Kountchou, V.R. Folifack Signing, R.L. Tagne Mogue, J. Kengne, P. Louodop, SaïdouAbstractDesigning simple chaotic circuits with complex dynamic behaviors that can generate coexisting and hidden attractors has attracted much interest recently. In this paper, a new voltage-tunable Colpitts oscillator based on a two op-amps voltage comparator that can exhibit self-excited and hidden behaviors is proposed. Only the intrinsic nonlinearity of the voltage comparators is responsible for the complex dynamic behaviors of the proposed model and no additionally nonlinear devices are required. In this circuit, a reference voltage source acts as a reversible control parameter, since it can be varied indifferently in a positive or negative direction. Basic dynamic properties of the proposed Colpitts oscillator are investigated and the entire dynamics is analyzed numerically based on standard nonlinear analytical tools. Very rich dynamic behaviors and phenomena are reported, including; hidden attractors, period-doubling bifurcations, antimonotonicity, bursting oscillations, offset-boosting, and coexistence of multiple attractors for a set parameter values of the system. PSpice simulations are also carried out to validate theoretical and numerical results. Furthermore, the feasibility of the proposed Colpitts oscillator is confirmed through a practical realization which is in good agreement with the theoretical results.
       
  • WLAN Bandwidth Support for Relay-based Upward Handover in WLAN/Cellular
           Systems
    • Abstract: Publication date: Available online 7 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): M. Shiri, R. BerangiAbstractHandover from WLAN to cellular network in loosely coupled WLAN/Cellular systems is considered as a new call and therefore is not given any priority in the cellular network. Hence, it induces a remarkable delay that makes loosely coupled WLAN/Cellular systems inappropriate for the online services. Due to this fact, during a handover from a WLAN to a cellular network, a mobile station (MS) may be trapped in a low bit rate region before completing the handover. This paper suggests to use relay stations (RS's) during a handover to extend WLAN coverage until the handover is completed. When RS’s are not available, especially in sparse hotspots, allocating a large amount of the WLAN bandwidth to the MS can assist the handover process. In contrast, in a dense hotspot, the probability of finding an appropriate RS is high. Thus, the handover could be completed by using the potential RS's inside the WLAN coverage. It is confirmed, by analytical modeling and simulation results, that the proposed method can reduce the call dropping probability and improve the handover performance.
       
  • A blocked MCC estimator for group sparse system identification
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Fei-Yun Wu, Kunde Yang, Xueli Sheng, Fuyi HuangAbstractThe maximum correntropy criterion (MCC) algorithm and its kernel based variants exhibit robust system identification against impulsive noise. However, MCC based methods have limited performance when processing sparse especially block sparse system. This study proposes a mixed norm constraint in the objective function and derives block sparse MCC (BSMCC) method and extends BSMCC method to an optimal version by choosing the adequate block size. In details, a mixed ℓ1,0-norm constraint is integrated into the cost function of the varied kernel MCC method. Then its iterative optimization is derived via finding the stochastic gradient direction. The optimal block size is selected by estimation error comparisons among 3 types of parallel computing for iterations in a setting interval. Furthermore, the performance analysis such as parameter setting and computational cost of BSMCC method are provided. Finally, the simulations and echo cancellations are conducted to confirm the superior performance of the proposed BSMCC and OBSMCC methods.
       
  • Buck converter with adaptive pass device employing capacitive and
           resistive power loss equalization
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Kemal Ozanoglu, Gunhan DundarAbstractThis paper presents a novel control technique to efficiently supply a wide range of output load current in a buck converter using an adaptive pass device at the output stage. The adaptive pass device segment size control technique is based on equalization of capacitive power loss and resistive power loss terms by taking into account load current, input supply voltage, temperature, process, and aging conditions; thus, leading to optimum efficiency at the output stage in a broad operating region. Power calculations are done in analog domain using a novel arithmetic cell called the adaptive gm stage. The additional power consumption introduced by the power calculation blocks is less than 1.4 μA, which enables high efficiency operation even in low load currents. The circuit and layout are designed in a standard 130 nm CMOS technology and simulation results show 5–35% efficiency increase for mid/low load currents compared to a fixed output stage buck converter. Compared to other reported adaptive pass device buck converters, 4% increase in peak power efficiency with 3× broader load current range has been achieved.
       
  • Performance analysis of MISO-MU-OHE-DCSK system over Rayleigh fading
           channels
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Gang Zhang, Changchang Zhao, Tianqi ZhangAbstractIn this paper, a novel non-coherent communication system, multi-user orthogonal high efficiency differential chaos shift keying (MU-OHE-DCSK) system is presented. In the proposed system, by using an orthogonal chaotic generator (OCG) to generate two orthogonal chaotic signals, therefore the intra-signal interference components in MU-OHE-DCSK are eliminated. As in high efficiency differential chaos shift keying (HE-DCSK), the reference signal is transmitted in the first time slot. The 2N data bits are spread by chaotic sequence and then separated through Walsh codes in the second time slot of the frame. As a result, the superiority of this proposed system is that it can enhance the spectral efficiency when compared with DCSK and HE-DCSK. Furthermore, using multiple antennas at the transmitter end, this system can inhibit the channel fading problem and then obtain more diversity gain. The BER formula of multiple-input single-output MU-OHE-DCSK (MISO-MU-OHE-DCSK) is derived under the assumption of the proposed system over Rayleigh fading channels, respectively. Theoretical analysis is consistent with simulation results and shows that the new system outperforms other DCSK-based systems.
       
  • Analysis of asymmetric coupling lines and design of a Wilkinson power
           divider based on harmonic suppression network
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Mohsen Hayati, Sepehr ZarghamiAbstractIn this paper, symmetric (equal impedance lines) and asymmetric coupling lines (unequal impedance lines) are analyzed and investigated. From the research, it has been ascertained that the coupling effect in the equal impedance lines creates a new transmission zero. Also, the coupling effect in unequal impedance can control two created transmission zeros. The purpose of this work is to design a network for suppressing large numbers of harmonics with a large number of controlled transmission zeros. Therefore, a harmonic suppression network (HSN) is designed based on asymmetric coupling lines. Designed HSN generates a large number of transmission zeros with an acceptable stopband bandwidth. The proposed HSN has been replaced with two quarter-wavelength transformers in the conventional Wilkinson power divider. The number of suppressed harmonics by the HSN is greater than the number of suppressed harmonics by the quarter-wavelength, while the size of the HSN is much more compact. Also, a power divider is designed based on the proposed HSN. The designed power divider has a compact size and low insertion loss for S21 and S31 at 1.2 GHz. The number of suppressed harmonics is up to the 16 harmonic. The measured results show a frequency operation range from 0.7 to 1.26 GHz (109.6%) with a more than 10-dB return loss. The isolation in the entire operation range, agreeing well with the simulation results.
       
  • A novel Dual-Band Double-Sided High-Impedance Surface (DB-DS-HIS) with
           systematic design methodology
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Maryam Samadpour Hendevari, Mohammad Bemani, Saeid NikmehrAbstractThis paper presents a systematic design methodology of dual-band double-sided high-impedance surface (DB-DS-HIS). The high impedance characteristics seen from both sides of the structure at two distinct frequencies are investigated theoretically based on the transmission line (TL) model and the surface impedance method. The proposed DB-DS-HIS is presented and parametric study on the reflection properties of the double-sided HIS structure loaded with additional patches/rings is given. Finally, the proposed DB-DS-HIS unit cells are combined as a chessboard structure to reduce the radar cross section (RCS). More than 15 dB RCS reduction in the first frequency band from 8 GHz to 12 GHz with maximum reduction of 37 dB at 10 GHz and more than 10 dB RCS reduction in the second frequency band from 14 GHz to 16 GHz with maximum reduction of 29 dB at 14.7 GHz is achieved. Since the structure is double sided, the RCS of the chessboard structure is reduced at the two frequency bands from both sides.
       
  • Performance evaluation of linearity and intermodulation distortion of
           nanoscale GaN-SOI FinFET for RFIC design
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Ajay Kumar, Neha Gupta, Shrey Kumar Tripathi, M.M. Tripathi, Rishu ChaujarAbstractThis work presents, performance evaluation of linearity and intermodulation distortion of novel nanoscale Gallium Nitride (GaN) Silicon-on-Insulator (SOI) N-channel FinFET (n-FinFET) for RFIC design and results so obtained are simultaneously compared with conventional (Si-based) FinFET and bulk GaN-based FinFET with 8 nm gate length. It is found that the proposed device enhances on-current (ION) by four times and thereby transconductance, subthreshold slope, threshold voltage, surface potential, and energy band (conduction band energy and valence band energy) profiles have been improved at ultra-low voltage power supply (VDS = 0.1 V). Thus, the improved electrical performance of GaN-SOI FinFET makes it suitable for low power and high-performance CMOS circuits. Also a further investigative study has been performed on the linearity behavior of GaN-SOI FinFET and the outcomes of the study have been compared with the results of the GaN Bulk FinFET and the conventional Silicon FinFET. The SOI device shows better linear performance in the likes of higher-order voltage and current intercept points as VIP2, VIP3, IIP3, and 1-dB compression point with lesser harmonic distortions as HD2, HD3 and, IMD3. Thus, the results with higher efficiency, better linearity, and distortionless performance pave the way for RFIC design.
       
  • An S-band 6-bit full 360° phase shifter using wideband quadrature
           generation with pole-zero manipulation
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Mostafa Nobakht Sarkezeh, Aminghasem SafarianAbstractIn this paper a 6-bit vector-sum phase shifter with a full 360° variable phase-shift range for S-band has been designed and simulated using standard 180 nm CMOS technology. A new In-phase and Quadrature (I and Q) network to generate quadrature signals with minimum I and Q amplitude mismatch over wide bandwidth is proposed and deployed in the vector sum phase shifter. The designed phase shifter achieves an RMS (root mean square) phase error less than 1.34° and an RMS amplitude error less than 0.43 dB over wide bandwidth of 2 – 4 GHz, resulting in a 6-bit resolution. The gain of phase shifter chain varies from 3 to −6 dB over S-band of 2 – 4 GHz. Moreover the input of phase shifter is widely matched to 50 Ω antenna. The proposed phase shifter draws 7.5 mA from 1.8 supply voltage. The active core chip size occupies an area of 0.143×0.122 mm2.
       
  • Highly compact microstrip patch design based on improved capacitive
           Minkowski fractal defected ground structure
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Guru Prasad Mishra, Biswa Binayak MangarajAbstractThis article proposes an effective approach for designing a highly compact patch antenna for wireless applications at 2.4 GHz. Size reduction is realized here by adding a modified Minkowski fractal defected ground structure (M-MFDGS) under the center of the radiating patch. The antenna miniaturization procedure follows a sensitivity study for the selection of appropriate DGS shape. Incorporating this highly capacitive M-MFDGS, the resonant frequency of the patch is reduced from 4.16 GHz to 2.4 GHz without any alteration in the physical size of the microstrip patch. This enables a 71% reduction in the radiating patch compared to the conventional antenna at the same operating frequency. The variation in the antenna resonance characteristics is also validated by an equivalent transmission-line model. The fabricated antenna prototype with a very low patch size of 0.15 λ0 × 0.13 λ0, has a 10-dB return loss bandwidth of 5.20%, a realized gain of 1.4 dBi, and radiation efficiency of 65% centered at 2.41 GHz. With this novel approach, the proposed miniaturized patch antenna is found to be a suitable candidate for portable wireless communications.
       
  • Frequency reconfigurable stepped impedance dipole antenna for wireless
           applications
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Manoj Mani, Remsha Moolat, Shameena V. Abdulrahiman, Anila P. Viswanathan, Vasudevan Kesavath, Mohanan PezholilAbstractA stepped impedance (SI) based frequency tunable dipole antenna for WLAN (2.4–2.48 GHz)/Bluetooth (2.4–2.48 GHz)/LTE (2–2.7 GHz)/wireless power transfer/UMTS (2.1 GHz)/WiMAX (2.5–2.7 GHz) applications has been investigated in this paper. The proposed antenna has an overall dimension of 0.408 λ0 × 0.245 λ0 × 0.013 λ0, where λ0 represents the free-space wavelength at the frequency 2.45 GHz. By embedding varactor diodes on the SI dipole antenna arms and varying the bias voltage, the effective electrical length of the antenna can be changed, leading to an electrically tunable antenna without changing the length of the antenna. The simulation and experiments are well matched and offer a 2:1 VSWR (S11 
       
  • Field coupling synchronization between chaotic circuits via a memristor
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Xiufang Zhang, Fuqiang Wu, Jun Ma, Aatef Hobiny, Faris Alzahrani, Guodong RenAbstractContinuous energy flow is pumped and propagated via the coupling components, which are activated to build coupling channel between two nonlinear circuits. When the coupling channels are bridged to different output ends, these coupling devices show much difference in pumping and balancing energy flow from the coupled circuits. In this paper, a memristor is used to bridge connection between different outputs ends of the Pikovsk-Rabinovich circuits, and coupling synchronization is investigated carefully. It is found that complete synchronization can be realized when the coupling channel is connected to the output ends for capacitors, while complete synchronization is blocked to stabilize phase synchronization when memristor is used to connect the output ends for tunnel diodes. Finally, the coupling mechanism is discussed by calculating the energy pumping in the coupling memristor. Indeed, the involvement of memristor in the coupling channel introduces a kind of nonlinear coupling as field coupling, and the synchronization transition and stability are much dependent on the intrinsic properties of the coupling channel.
       
  • Reduced complexity null subspace channel impulse response based blind
           identification
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Rabah Maoudj, Juan Medeiros, Michel Terré, Alexandre ChristopheAbstractHigh order statistics blind identification algorithms proposed in Terre et al. (2014) and based on the Viterbi & Viterbi Algorithm which suffers on the 2π/2p ambiguity when the order of used statistics is p. In order to remedy this problem, we propose the null subspace channel impulse response algorithm. However, the complexity of this algorithm is relatively high, then a method to reduce this complexity is proposed. It consists on splitting a large size optimization problem to some parallel low dimension ones. Furthermore, a novel regularization method is proposed and this method gives results globally comparable to that obtained with the subspace method and specifically higher at low SNR, as we will give an application hereafter. In spite of its relatively high complexity, a parallel architecture can be applied to this algorithm, if one wants a rapid execution to meet real-time constraints.
       
  • Soft fault diagnosis of linear circuits with the special attention paid to
           the circuits containing current conveyors
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Michał Tadeusiewicz, Stanisław HałgasAbstractThis paper deals with soft fault diagnosis of linear analog circuits and concentrates on the circuits including second generation current conveyors. Properties of these circuits are taken into account and an appropriate realistic conveyor model is put forward. The fault diagnosis includes fault detection, locating faulty elements from among all circuit elements, and estimating their values. The diagnostic method developed in this paper exploits a measurement test in an AC state and uses the nonlinear programming as a mathematical tool. Values of the faulty parameters may belong to wide ranges around their nominal values. For illustration a real-life current conveyor circuit is laboratorily and numerically tested. Proposed method efficiently diagnoses different faults giving correct results in short time. Although the method is dedicated to single fault diagnosis, it can be generalized to double and triple faults either. However, in the case of multiple faults it is less effective.
       
  • Retina-inspired neuromorphic edge enhancing and edge detection
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Melih Yildirim, Firat KacarAbstractIn this paper, a novel analog retinomorphic block performing the edge enhancing and edge detection caused by lateral inhibition phenomenon is proposed. This phenomenon, which occurs in human retina, causes the visual acuity to improve in the edge regions of the object. In contrast to the negative meaning of the word “inhibition”, this type of behavior causes the human eye to act as an analogue image processing chip. The reason for that is the edges of object are enhanced and the contrast ratios in the edge regions of an object are increased owing to the lateral inhibition. We adapt the process of convolution and the concept of image masking used in digital image signal processing method to analog image signal processing method. Our proposed circuit, which exhibits edge enhancing behavior thanks to lateral inhibition, consists of only current mirrors and current subtractor circuits. We obtain the analysis results via a simple circuit design having lateral inhibition feature and the results are quite similar to that occurring in human retina. In addition to the ability of lateral inhibition, we utilize from the masking property of the lateral inhibition circuit and change the coefficients of the mask in order to obtain an edge detecting circuit. For this purpose, we use a mask whose sum of the coefficients is equal to zero. Two different 500 × 500 pixel silicon networks are designed for both edge enhancement and edge detection circuits. We have analyzed an image with the helped of both edge enhancement and edge detection circuits. Analyses results reveal that our suggested block, which is set up using only MOS transistors, can enable edge enhancement and edge detection in grayscale image and lateral inhibition behavior of the human retina can be provided using a simple electronic circuit design which has the ability of performing convolution operation. TSMC CMOS 0.18 μm process model is utilized to simulate proposed two analog circuit networks.
       
  • A metasurface based low-profile reconfigurable antenna with pattern
           diversity
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Huy Hung Tran, Tuan Tu LeAbstractA low-profile reconfigurable antenna with a capability of generating multidirectional beams is presented in this paper. The design consists of a 4 × 4 unit cells metasurface (MS), a four-slotted ground plane, and a reconfigurable feeding network. By offsetting the slots from the center of MS, the unit cells of the MS can be excited with different phases and the main beam of the antenna can be steered to the desired direction. The pattern reconfigurablility is conveniently accomplished by electrically controlling the ON/OFF states of four p-i-n diodes on the feeding network to excite the proper slot. The final antenna has low profile of 0.04λo at the center operating frequency. The measurement indicates that the antenna has wide operating band of 10.4% by combining two adjacent resonances generated by the slot and the MS. Besides, the antenna exhibits four distinct beams with a peak gain value of 5.6 dBi. It is worth to note that compared to other pattern reconfigurable antennas in literature, the proposed design has advantages of low profile, wide operating bandwidth, and small number of p-i-n diodes.
       
  • Performance analysis of power beacon-assisted energy harvesting NOMA
           multi-user relaying system over Nakagami-m fading channels
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Tran Manh Hoang, Nguyen Trung Tan, Xuan Nam Tran, Le The DungAbstractIn this paper, we propose and analyze a multi-user non-orthogonal multiple access (NOMA) relaying system under the effect of Nakagami-m fading. In this system, both source and the relay harvest the energy from a multiple-antenna power beacon (PB) in the first time duration by using the time switching protocol and then use the harvested energy to transmit and receive the signals in the remaining time duration. We derive the exact closed-form expressions of the outage probability in two cases of successive interference cancellation (SIC), i.e., perfect SIC and imperfect SIC. Moreover, we determine the optimal time switching ratio that maximizes the system throughput. We also compare the achievable sum rate of the proposed NOMA relaying system with that of the orthogonal multiple access (OMA) relaying system. The correctness of all derived mathematical expressions results in this paper is verified by Monte-Carlo simulations. Numerical results show that: (1) the fading severity of wireless channels has a significant impact on the outage probability and the diversity; (2) increasing the number of antennas of PB helps to lower the outage probability, decrease the energy harvesting time, and increase the throughput; (3) the sum rate of the proposed NOMA relaying system is proportional to the SIC quality and is higher than that of the OMA relaying system in the low and moderate signal-to-noise ratio (SNR) regimes.
       
  • On-chip miniaturized antenna in CMOS technology for biomedical implant
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Alphonsos A Masius, Yan Chiew WongAbstractBioimplant devices need to be small to be considered safe. At the same time, one of the major challenges in its design is the size and lifetime of the battery. Therefore, replacing the battery with a miniaturized and integrated wireless power harvester aid the design of sustainable biomedical implants in smaller volumes. This study presents the design of on-chip miniaturized antenna in CMOS technology at 900 MHz for RF energy harvesting system-on-chip (SoC) application. The design approach utilizes 0.18 µm CMOS technology from SilTerra. Effect of the thickness of the SiO2 substrate to the return loss and gain of the antenna has been evaluated. It is found that thicker substrate provides a better response, but subject to manufacturability of selected process technology. The developed antenna only occupied an area of 700 × 550 µm2. The antenna has been fabricated along with integrated matching circuit and rectifier. The measured performance of the antenna deviates from simulation due to parasitic interaction between the antenna and matching circuit structure. This work shows a complete workflow from design consideration to fabrication and measurement setup of CMOS antenna that will not only be applicable to 0.18 µm CMOS, but to other CMOS technology as well.
       
  • A new CFOA based grounded capacitance multiplier
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Mehmet Dogan, Erkan YuceAbstractA new CFOA based grounded capacitance multiplier is proposed in this study. The proposed grounded capacitance multiplier that does not need any passive component matching conditions employs two CFOAs, a grounded capacitor and a couple of resistors. A number of frequency and time domain analyses for the proposed grounded capacitance multiplier are performed through the SPICE simulation program. During the simulations, ±9 V supply voltages and a commercially available AD844 model are used. In addition to these, an experiment in time domain is made to validate the performance.
       
  • Compact microstrip lowpass filter with high harmonics suppression using
           defected structures
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Thulaseedharan K. Rekha, Parambil Abdulla, Puthenveetil M. Jasmine, Arunodayam R. AnuAbstractA compact microstrip lowpass filter with sharp selectivity and wide stopband designed on the basis of dual-plane, is presented. Initially, a basic one pole defected ground structure (DGS) filter is modified so as to achieve sharp selectivity as well as compact size. The modified DGS reduces the circuit size of the filter by 68.8%. To suppress the higher order harmonics, mirrored symmetrical uniform impedance stubs are designed in the top surface of the substrate, thereby wide stopband up to 20 GHz is achieved. The stopband suppression level of the filter is improved by incorporating a spurline resonator which acts as a defected microstrip structure (DMS) in the top microstrip line. The designed filter has 3 dB cutoff frequency of 2.11 GHz with high relative stopband bandwidth of 159.2% within the rejection level of 18 dB. The wide passband frequency range of the proposed filter covers the GSM, GPS, Wi-Fi communications and various L-band applications such as aircraft surveillance etc.
       
  • Improving the performance of a junctionless carbon nanotube field-effect
           transistor using a split-gate
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Khalil TamersitAbstractIn this paper, a novel junctionless carbon nanotube field-effect transistor (JL-CNTFET) endowed with a split coaxial gate (SCG) is proposed through a rigorous self-consistent simulation. This latter is based on solving self-consistently the Schrödinger and Poisson equations using the non-equilibrium Green's function (NEGF) formalism and the finite difference method (FDM), respectively. It has been found that the suggested SCG JL-CNTFET can exhibit significantly improved switching performance including the off-current, current ratio, intrinsic delay and power-delay product, due to the decreasing of band-to-band tunneling via the split-gate strategy. The obtained results indicate that the proposed SCG JL-CNTFET can be considered as a promising device for the futuristic high-performance integrated circuits intended for low-power and high-speed applications.
       
  • Improved statistical variability and delay performance with junctionless
           inserted oxide FinFET
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): V. Jegadheesan, K. Sivasankaran, Aniruddha KonarAbstractJunctionless inserted oxide FinFET (JL-iFinFET) is presented, its performance metrics are quantified and compared with JL-FinFET and JL-Stacked-Nanowire-FET (JL-SNWFET) respectively for the same foot-print on the wafer. The Random-Dopant-Fluctuation (RDF) and Metal-Gate-Granularity (MGG) are major variability sources in nano-transistors. Impedance Field Method is used to analyze the statistical variability performance of all three structures caused by RDF and MGG. The result shows JL-SNWFET provides superior DC figure-of-merits and 40% less statistical variability than JL-FinFET with a 10% increase in delay and considerable increase in fabrication complexity. The JL-iFinFET offers 30% lesser process-induced threshold voltage and on-current variations compare to JL-FinFET, without deteriorating delay and RF metrics due to its superior electrostatic control over the channel and multi-channel configuration. Fabrication of JL-iFinFET is also possible without adding much complexity in FinFET process it can be a major contender for continued scaling with JL-Transistors (JLTs).
       
  • A wideband quad-layer transmitarray antenna with double cross slot rings
           elements
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): M. Moshiri, A. Ghafoorzadeh-Yazdi, A.A. HeidariAbstractThis paper introduces and studies a multi-layer frequency selective surface structure as a new unit-cell to design a wideband quad-layer transmitarray antenna. The proposed unit-cell consists of a double cross slot rings (DCSRs) on a rectangular patch. This unit-cell supports the transmission phase range response about 400° with magnitude better than −3 dB at 10 GHz and its sensitivity to the feed incident angle, up to 30°, is very low. To validate the design approach, a quad-layer transmitarray antenna, which each layer contains 169-element, is designed at 10 GHz and then fabricated and measured. The measured results show 1-dB gain bandwidth of 25% (9.75–12.53 GHz) with 23.34 dB maximum gain and 38.3% aperture efficiency at 10.3 GHz. Moreover, the 2-dB and 3-dB gain bandwidth are 31% (9.45–12.92 GHz) and 36% (9.30–13.35 GHz), respectively. As a result, the proposed element has the broadband performance and therefore can be a proper candidate to design wideband transmitarray antennas.
       
  • An interference management approach for CR-assisted cooperative D2D
           communication
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Zohre Mashayekh Bakhsh, Javad Zeraatkar Moghaddam, Mehrdad ArdebilipourAbstractIn this paper, we investigate a cooperative D2D communication in cognitive radio (CR) networks, which is composed of two secondary links, one primary link, and a relay network. In cases where data transmission is not performed directly, the source devices can communicate with their destinations via the relay network, which consists of some idle secondary devices. We propose a clustering relay selection (RS) method to enable simultaneous transmission of primary and secondary sources. The proposed RS classifies the relay devices into two clusters and assigns one cluster to the primary link and another to the secondary links. Furthermore, an interference management approach is proposed to improve the system performance. By jointly employing the proposed RS and a cooperative beamforming (CBF) method in each cluster, the investigated approach can maximize the received SINR at the destinations while maintaining the interference plus noise power below a predefined threshold. To investigate the performance, we optimize the proposed RS and CBF vectors by solving a convex semidefinite problem using the bisection search algorithm. Simulation results are provided to show the efficiency of the investigated strategy.
       
  • Single-layer wideband differential phase shifter using high-order
           multimode resonator structure
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Mohammad Karim Alizadeh, Hossein Shamsi, Mohammad Bagher Tavakoli, Hadi AliakbarianAbstractIn this paper, a new strategy for the design of a single-layer wideband phase shifter is proposed. The phase shifter employs the 7th order multimode resonator and does not require any coupling structure. Assuming a specific return loss (e.g. 15, 20 and 25 dB), the phase shifter is analyzed for a variety of phase shifts (e.g. 45° to 270°) in differential mode. To validate this design, a wideband phase shifter with phase shift of 90° ± 4.4° is fabricated in the frequency range of 2.2–7.35 GHz, which implies 107.8% fractional bandwidth. The fabricated phase shifter has a return loss of S11-1.28dB. The synthesized, simulated, and measured results are in good agreement with each other.
       
  • Cooperative non-orthogonal multiple access for two-way relay networks
    • Abstract: Publication date: February 2020Source: AEU - International Journal of Electronics and Communications, Volume 115Author(s): Zhaoxi Fang, Jun Li, Yingzhi LuAbstractIn this paper, we propose a cooperative non-orthogonal multiple access (NOMA) based relaying scheme for a two-way relay network (TWRN) where one user communicates with the base station (BS) directly while the other indirect-link user exchanges message with the BS via the help of a decode-and-forward (DF) relay station. We analyze the sum-rate performance of the proposed scheme, and derive a closed-form expression for the ergodic capacity. Furthermore, we analyze the asymptotic performance in the high signal-to-noise ratio (SNR) region. Simulation results show that the proposed DF based cooperative NOMA TWR transmission scheme achieves a much higher sum-rate than its AF counterpart and conventional time-division multiple access (TDMA) based scheme.
       
  • A Review of GaN HEMT BroadBand Power Amplifiers
    • Abstract: Publication date: Available online 3 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): K. Husna Hamza, D. NirmalAbstractThe unique material properties of GaN, wide bandgap, high thermal con- ductivity, high breakdown voltage, high electron mobility and the device properties of GaN HEMT (High Electron Mobility Transistor) namely low parasitic capacitance, low turn on resistance and high cut off frequencies make it a good choice to use in a power amplifier. During this era of wire- less communication with complex modulation schemes having high peak to average power ratio, maintaining the efficiency and linearity of power am- plifier is a tough task. In this paper an extensive review of GaN HEMT based power amplifier is presented. First of all, GaN technology is described and compared with other semiconductor technologies. The different classes of power amplifier like class B, C ,D , E , F and J with GaN is discussed. Efficiency and linearity enhancement techniques like envelope tracking, Do- herty power amplifier and digital predistortion used in applications with high PAPR waveforms is described. The advantages of GaN MMIC (Microwave Monolithic Integrated Circuit) are reviewed. Finally different thermal man- agement solutions used for GaN power amplifier to cope with its self heating phenomenon are explained.
       
  • A Space-Frequency Block Codes MIMO Single-Carrier Code-Frequency-Division
           Multiple Access System
    • Abstract: Publication date: Available online 3 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Abdullah Y. Alamri, Ehab F. BadranAbstractIn this paper, a novel space frequency block codes MIMO single-carrier code-frequency-division multiple access (SFBC MIMO SC-CFDMA) transceiver is proposed. The proposed SFBC SC-CFDMA system allocates a unique spreading code for each user. The proposed SFBC SC-CFDMA system offers robustness against the effect of carrier frequency offsets (CFOs). The proposed SFBC SC-CFDMA system is suggested to improve both of the peak-to-average power ratio (PAPR) performance and the bit error rate (BER) performance. The simulation results show that the proposed SFBC SC-CFDMA system has superior improvements in the BER performance over the traditional SFBC SC-FDMA system. Moreover, the PAPR performance of the proposed SFBC SC-CFDMA system is better than that of the traditional system for the case of a localized mapping scheme. Furthermore, BER analysis for the proposed SFBC SC-CFDMA and traditional SFBC SC-FDMA system over a frequency-selective Rayleigh fading channel is presented for the case of zero-forcing (ZF) equalizer and QPSK modulation.
       
  • Bandpass filter based on asymmetric funnel shaped resonators with ultra
           wide upper stopband characteristics
    • Abstract: Publication date: Available online 3 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Ami Iqubal, P. AbdullaAbstractA novel microstrip bandpass filter with wide passband, good skirt selectivity and very good passband reflection characteristics using asymmetric funnel shaped resonators is presented in this paper. IE3D simulation software is used for the design and analysis of the proposed filter and the electric field intensities at various frequencies of interest are plotted and verified the role of even and odd mode resonances in achieving wide passband. There are six modes, including three even and three odd modes for the developed filter. Novel equations are derived for finding out the location of transmission zeros and the role of resonators in achieving sharp selectivity are verified. The out of band performance of filter is very good with a suppression level greater than 20 dB upto 24.2 GHz. The centre frequency of the filter is 5.68 GHz with a fractional bandwidth of 97.57 %. The fabrication process is carried out using MITS 11 Autolab fabrication machine with the low cost FR4 substrate and verified the performance improvement of the developed filter.
       
  • End-to-end Performance of Hybrid DF/AF (HDAF) Relayed Underlay Cognitive
           Radio Networks
    • Abstract: Publication date: Available online 3 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Anita Sharma, Mona Garg, Swaran Ahuja, Moin-UddinAbstractIn the presented work, the performance analysis of an underlay cognitive relay network with a hybrid-decode/amplify-and-forward relaying protocol is undertaken. Since the system is an underlay system, the secondary network will communicate simultaneously with the primary network. Hence interference temperature will act as a constraint to keep the secondary communication from interfering with the primary transmission. To ensure this, secondary transmit powers need to be kept below a pre-defined threshold level. Severe multi-path fading and shadowing or a long distance between the secondary source and the destination make a direct link between the two infeasible. These nodes can only be linked by a relay between the two. All the radio links in the system are characterized by the extended generalized-K fading distribution. The closed form expressions for the outage probability and ergodic channel capacity of the system are derived. The system outage performance and capacity with hybrid-decode/amplify-and-forward relay is compared to the performance with amplify-and-forward and decode-and-forward relays. Optimum relay position for best outage performance is also investigated. Further, the results of the performance analysis of the system are also illustrated by the numerical plots.
       
  • Efficiency Improvement and Cross-Polarization Reduction of Single-Fed
           Frequency-Scan Leaky Wave Microstrip Antennas by Using an M-Shape
           Metasurface as the WAIM Layer
    • Abstract: Publication date: Available online 2 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Mahdi Fartookzadeh, Seyyed Hossein, Mohseni ArmakiAbstractIncreasing the efficiency and reducing the cross polarization of a single-fed leaky wave antenna by using a wide-angle impedance matching (WAIM) layer are studied in this paper. A wideband serial-fed patch array on a two layer substrate is employed as the leaky wave array. Dimensions of the patch array are optimized for the lowest reflection coefficient between 6 GHz and 7 GHz. The proposed antenna is indeed a frequency-scan antenna in this frequency range. Miniaturization of the proposed leaky wave microstrip antenna is achieved by using circular lines instead of straight lines between the patches. Reducing the separations between the array elements (microstrip patches) led to the sidelobe level reduction of the radiation patterns. Further improvements on the antenna results are obtained by using an anisotropic metasurface WAIM layer. The proposed metasurface layer is composed of printed M-shape unit-cells on a thin substrate, leading to the gain enhancement, sidelobe level reduction, cross-polarization reduction and reflection coefficient reduction of the antenna. Finally, the predicted results are validated by using experimental results, indicating good agreements. As a result, the performance improvement of the antenna by using the WAIM layer is observed in the simulations and measurements, clearly.
       
  • Coprime sparse circular array with little angular dependence and reduced
           mutual coupling
    • Abstract: Publication date: Available online 2 January 2020Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Guo-jun Jiang, Xing-peng Mao, Yong-tan LiuAbstractSparse circular arrays (SCAs) have many advantages, e.g., providing 360∘ azimuthal coverage and reducing mutual coupling. This paper presents a novel coprime sparse circular array (CSCA) for significantly improving underdetermined direction of arrival (DOA) estimation performance compared to the existing SCAs, e.g., nested sparse circular array (NSCA) and super nested sparse circular array (S-NSCA). The CSCA is obtained by connecting two sparse subarrays concircularly with two displacements, and the sensor positions are determined by a systematic procedure. The array geometry has closed-form expressions and the inter-sensor spacings of the two sparse subarrays are coprime. The CSCA contains all the good properties of the SCAs. Simultaneously, the CSCA has less angular dependence due to its nearly uniform sensor distribution and has much smaller mutual coupling effect by enlarging its minimum inter-sensor spacing, when compared to the NSCA and S-NSCA. Due to its merits, it can be applied to sonar, communication, and navigation, to name a few. Then an l1-based method is used for underdetermined DOA estimation. Theoretical analysis and simulation results show the superiority of the CSCA.
       
  • Diffusion-Bonded W-band Monopulse Array Antenna for Space Debris Radar
    • Abstract: Publication date: Available online 31 December 2019Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Eduardo Garcia-Marin, Jose-Luis Masa-Campos, Pablo Sanchez-OlivaresAbstractIn this letter, the design and fabrication of a W-band high-gain monopulse array antenna are presented. The antenna is conceived as a proof of concept for a space debris detection project to develop an on-board radar for a satellite system. The antenna array consists of 16 by 16 circularly polarized radiating cavities fed by a corporate waveguide network with an amplitude taper. An underlying monopulse beamforming network is implemented in waveguide technology as well, providing monopulse capability in both main radiating planes. By means of diffusion bonding, the antenna has been fabricated in a single piece, despite its intricate, multilayer topology. Moreover, the experimental performance shows high agreement with simulations, which is remarkable due to the high sensitivity to manufacturing tolerances at this frequency. Over a 10% bandwidth is experimentally achieved for efficiency over a 75%, axial ratio under 3 dB and impedance matching under −10 dB.
       
  • A Compact and Efficient Graphene FET Based RF Energy Harvester for Green
           Communication
    • Abstract: Publication date: Available online 30 December 2019Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Neeta Singh, Sachin Kumar, Binod Kumar Kanaujia, Mirza Tariq Beg, Mainuddin, Sandeep KumarAbstractThis paper presents a graphene field effect transistor (FET) based rectenna with substrate-integrated waveguide (SIW) broadband approach for RF energy harvesting application. The proposed structure of integrated rectenna consists of a graphene FET rectifier and an SIW antenna operating in the (S11
       
  • Cross-Finned UWB Monopole for Wireless Applications: Design Insight and
           Characterization
    • Abstract: Publication date: Available online 28 December 2019Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Debarati Ganguly, Debatosh Guha, Yahia M.M. AntarAbstractA simple yet novel cross-finned geometry of a monopole has been explored to realize a strong contender in the family of ultra-wideband antennas. This promises a consistent monopole like radiation over an ultra-wide impedance bandwidth (127%) with improved radiation characteristics. An extensive study supported by experiments has resulted in a reliable design guideline with a strong physical insight. A cross-finned top loaded structure having individual fin length (L) 11 mm and width (W) 5 mm and fin thickness (t) 0.7mm, fed by probe pin of height h = 2 mm, is fitted to a circular ground plane of radius (Ga) 15 mm. It has been experimentally demonstrated to operate from 5-22.5 GHz with as much as 1-7 dBi peak gain and over the band high co-to cross polarization isolation (26-31 dB). The design is found to exhibit desired transmission and reception characteristics in time domain and is extendable up to 32 GHz to the upper side and 1.5 GHz to the lower side of the microwave band. This commercially viable design should find potential applications in compact and miniaturized wireless transceiver systems.
       
  • Robust Blind Multiuser Detection in Overdetermined MIMO Channels Using
           Wavelet Transform
    • Abstract: Publication date: Available online 28 December 2019Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Vahid Karami, Behzad Mozaffari TazehkandAbstractIn the conventional multiple input multiple output (MIMO) systems, the receiver needs users to transmit their channel state information (CSI) to the receiver, but this approach increases bandwidth usage and affects spectral efficiency, and decreases effective data rate. Since the spectrum is a limited resource, blind source separation (BSS) approaches are efficient and promising options for the MIMO systems in a way that they do not require CSI to detect and separate the users’ data. On the other hand, one of the interesting techniques for denoising signals is to use discrete wavelet transform (DWT). The main objective of this paper is to present an application of DWT-BSS approach for the MIMO systems for the case where more receiver antennas than transmitter (users’) antennas are available. One of the simple approaches in BSS is to use the natural gradient algorithm (NG) which has linear convergence speed and has disappointing results in impulsive noise environments. We have used complex FastICA rather than the NG because of its cubic convergence speed and robustness to noise. Our simulations demonstrate that the proposed DWT-BSS scheme outperforms the NG method especially when channel noise becomes different from the additive white Gaussian noise (AWGN).
       
  • A New flip-flop Based On Discrete-Time Parametric Amplifier
    • Abstract: Publication date: Available online 26 December 2019Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Mehdi Ghavidel Jaliseh, Abdolreza Nabavi, Hadi Saiedpour Azar, Jila Amini-sheshdehAbstractThis paper introduces a low power flip-flop based on the discrete-time parametric amplifier, with improved rise (fall) time, setup-time, hold-time, and area. Post-layout simulation result of the proposed flip-flop in a 180 nm CMOS technology with 3.33 GHz frequency illustrates about 21% of the power consumed by CML flip-flop and about 30% improvement in the clock-to-q delay. Also, the simulation shows improved rise (fall) time, lower data-to-q delay compared to dynamic CML and Footless flip-flop, lower area than Charge Steering flip-flops without the need for additional return-to-zero to non-return-to-zero conversion circuitry. When using this flip-flop as a slicer in a decision feedback equalizer (DFE) circuit of a serial link receiver of 1 m Nelco backplane channel, the post-layout simulation results show that the DFE circuit based on the parametric flip-flop has about 50% improvement of power consumption in comparison with the conventional CML DFE circuit in identical conditions.
       
  • Outage Probability of NOMA System with Wireless Power Transfer at Source
           and Full-Duplex Relay
    • Abstract: Publication date: Available online 16 October 2019Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Ba Cao Nguyen, Tran Manh Hoang, Phuong T. Tran, Tan N. NguyenAbstractIn this paper, we analyze the performance of a novel communication scheme that combines three new techniques, namely energy harvesting (EH), full-duplex (FD) relay and cooperative non-orthogonal multiple access (NOMA). In this scheme, both the source and the relay harvest energy from the power beacon (PB) at the first phase of the transmission block and then use the harvested energy to transmit messages during the remaining phase. In this proposed EH-FD-NOMA system, the FD relay employs the amplify-and-forward scheme. We consider two destinations, one of them is far from the FD relay and the other is near the FD relay. Based on the mathematical calculation, we derive the closed-form expressions for the outage probability (OP) of the two users of interest. The numerical results show that the performance at two destinations can be maintained at the same level with proper power allocation. Furthermore, for each value of the PB transmit power, there exists an optimal value for the EH time duration to improve the performance of both users. In addition, the impact of the residual self-interference (RSI) due to imperfect self-interference cancellation (SIC) at the FD relay is also considered. Finally, numerical results are demonstrated through Monte-Carlo simulations.
       
  • Spatial-polarization diversity HAP-MIMO transmission system for emergency
           high-capacity mobile communications
    • Abstract: Publication date: Available online 28 August 2019Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Lei Shi, Lei Zhao, Yanming Liu, Qi LiAbstractThe deployment of high-altitude platforms (HAPs) as an emergency communication system is a cost-effective method to deal with the decrease in channel capacity caused by shadows or multipath fading at low elevation angles. This study proposes a 4 × 4 multiple-input multiple-output (MIMO) scheme that employs spatial and polarization diversity to improve the channel capacity for HAP communication systems. This scheme utilizes the advantages of HAP size to install two pairs of dual-polarized antennas between HAP and mobile terminals to form a 4 × 4 spatial-polarized diversity MIMO system to counteract shadows and multipath fading. The polarization and spatial correlation matrices are obtained through the reasonable expansion of a 2 × 2 polarized parametric or spatial geometry MIMO channel model. Simulation results show that the proposed 4 × 4 MIMO transmission scheme can effectively improve the channel capacity by 1.5 times compared with the existing satellite 2 × 2 dual-polarization MIMO system at low elevation angles under typical scenarios.
       
 
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