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COMPUTER SCIENCE (1198 journals)                  1 2 3 4 5 6 | Last

Showing 1 - 200 of 872 Journals sorted alphabetically
3D Printing and Additive Manufacturing     Full-text available via subscription   (Followers: 20)
Abakós     Open Access   (Followers: 4)
ACM Computing Surveys     Hybrid Journal   (Followers: 27)
ACM Journal on Computing and Cultural Heritage     Hybrid Journal   (Followers: 8)
ACM Journal on Emerging Technologies in Computing Systems     Hybrid Journal   (Followers: 11)
ACM Transactions on Accessible Computing (TACCESS)     Hybrid Journal   (Followers: 3)
ACM Transactions on Algorithms (TALG)     Hybrid Journal   (Followers: 15)
ACM Transactions on Applied Perception (TAP)     Hybrid Journal   (Followers: 5)
ACM Transactions on Architecture and Code Optimization (TACO)     Hybrid Journal   (Followers: 9)
ACM Transactions on Autonomous and Adaptive Systems (TAAS)     Hybrid Journal   (Followers: 7)
ACM Transactions on Computation Theory (TOCT)     Hybrid Journal   (Followers: 12)
ACM Transactions on Computational Logic (TOCL)     Hybrid Journal   (Followers: 3)
ACM Transactions on Computer Systems (TOCS)     Hybrid Journal   (Followers: 17)
ACM Transactions on Computer-Human Interaction     Hybrid Journal   (Followers: 14)
ACM Transactions on Computing Education (TOCE)     Hybrid Journal   (Followers: 5)
ACM Transactions on Design Automation of Electronic Systems (TODAES)     Hybrid Journal   (Followers: 3)
ACM Transactions on Economics and Computation     Hybrid Journal  
ACM Transactions on Embedded Computing Systems (TECS)     Hybrid Journal   (Followers: 3)
ACM Transactions on Information Systems (TOIS)     Hybrid Journal   (Followers: 19)
ACM Transactions on Intelligent Systems and Technology (TIST)     Hybrid Journal   (Followers: 7)
ACM Transactions on Interactive Intelligent Systems (TiiS)     Hybrid Journal   (Followers: 3)
ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP)     Hybrid Journal   (Followers: 9)
ACM Transactions on Reconfigurable Technology and Systems (TRETS)     Hybrid Journal   (Followers: 6)
ACM Transactions on Sensor Networks (TOSN)     Hybrid Journal   (Followers: 7)
ACM Transactions on Speech and Language Processing (TSLP)     Hybrid Journal   (Followers: 8)
ACM Transactions on Storage     Hybrid Journal  
ACS Applied Materials & Interfaces     Full-text available via subscription   (Followers: 28)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 2)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Ad Hoc Networks     Hybrid Journal   (Followers: 11)
Adaptive Behavior     Hybrid Journal   (Followers: 11)
Advanced Engineering Materials     Hybrid Journal   (Followers: 28)
Advanced Science Letters     Full-text available via subscription   (Followers: 10)
Advances in Adaptive Data Analysis     Hybrid Journal   (Followers: 7)
Advances in Artificial Intelligence     Open Access   (Followers: 15)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 19)
Advances in Computer Science : an International Journal     Open Access   (Followers: 15)
Advances in Computing     Open Access   (Followers: 2)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 51)
Advances in Engineering Software     Hybrid Journal   (Followers: 27)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 13)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 22)
Advances in Human-Computer Interaction     Open Access   (Followers: 19)
Advances in Materials Sciences     Open Access   (Followers: 14)
Advances in Operations Research     Open Access   (Followers: 12)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 6)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Remote Sensing     Open Access   (Followers: 44)
Advances in Science and Research (ASR)     Open Access   (Followers: 5)
Advances in Technology Innovation     Open Access   (Followers: 5)
AEU - International Journal of Electronics and Communications     Hybrid Journal   (Followers: 8)
African Journal of Information and Communication     Open Access   (Followers: 8)
African Journal of Mathematics and Computer Science Research     Open Access   (Followers: 4)
AI EDAM     Hybrid Journal  
Air, Soil & Water Research     Open Access   (Followers: 11)
AIS Transactions on Human-Computer Interaction     Open Access   (Followers: 5)
Algebras and Representation Theory     Hybrid Journal   (Followers: 1)
Algorithms     Open Access   (Followers: 11)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 5)
American Journal of Computational Mathematics     Open Access   (Followers: 4)
American Journal of Information Systems     Open Access   (Followers: 5)
American Journal of Sensor Technology     Open Access   (Followers: 4)
Anais da Academia Brasileira de Ciências     Open Access   (Followers: 2)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 7)
Analysis in Theory and Applications     Hybrid Journal   (Followers: 1)
Animation Practice, Process & Production     Hybrid Journal   (Followers: 5)
Annals of Combinatorics     Hybrid Journal   (Followers: 4)
Annals of Data Science     Hybrid Journal   (Followers: 11)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 12)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Software Engineering     Hybrid Journal   (Followers: 13)
Annual Reviews in Control     Hybrid Journal   (Followers: 6)
Anuario Americanista Europeo     Open Access  
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applied and Computational Harmonic Analysis     Full-text available via subscription   (Followers: 1)
Applied Artificial Intelligence: An International Journal     Hybrid Journal   (Followers: 12)
Applied Categorical Structures     Hybrid Journal   (Followers: 2)
Applied Clinical Informatics     Hybrid Journal   (Followers: 2)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 11)
Applied Computer Systems     Open Access   (Followers: 2)
Applied Informatics     Open Access  
Applied Mathematics and Computation     Hybrid Journal   (Followers: 33)
Applied Medical Informatics     Open Access   (Followers: 10)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Soft Computing     Hybrid Journal   (Followers: 16)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Applied System Innovation     Open Access  
Architectural Theory Review     Hybrid Journal   (Followers: 3)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 5)
Archive of Numerical Software     Open Access  
Archives and Museum Informatics     Hybrid Journal   (Followers: 142)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5)
arq: Architectural Research Quarterly     Hybrid Journal   (Followers: 7)
Artifact     Hybrid Journal   (Followers: 2)
Artificial Life     Hybrid Journal   (Followers: 7)
Asia Pacific Journal on Computational Engineering     Open Access  
Asia-Pacific Journal of Information Technology and Multimedia     Open Access   (Followers: 1)
Asian Journal of Computer Science and Information Technology     Open Access  
Asian Journal of Control     Hybrid Journal  
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
Australian Educational Computing     Open Access   (Followers: 1)
Automatic Control and Computer Sciences     Hybrid Journal   (Followers: 4)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Automatica     Hybrid Journal   (Followers: 11)
Automation in Construction     Hybrid Journal   (Followers: 6)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 9)
Basin Research     Hybrid Journal   (Followers: 5)
Behaviour & Information Technology     Hybrid Journal   (Followers: 52)
Big Data and Cognitive Computing     Open Access   (Followers: 2)
Biodiversity Information Science and Standards     Open Access  
Bioinformatics     Hybrid Journal   (Followers: 291)
Biomedical Engineering     Hybrid Journal   (Followers: 15)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 21)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 37)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 45)
British Journal of Educational Technology     Hybrid Journal   (Followers: 148)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 12)
c't Magazin fuer Computertechnik     Full-text available via subscription   (Followers: 1)
CALCOLO     Hybrid Journal  
Calphad     Hybrid Journal  
Canadian Journal of Electrical and Computer Engineering     Full-text available via subscription   (Followers: 14)
Capturing Intelligence     Full-text available via subscription  
Catalysis in Industry     Hybrid Journal   (Followers: 1)
CEAS Space Journal     Hybrid Journal   (Followers: 2)
Cell Communication and Signaling     Open Access   (Followers: 2)
Central European Journal of Computer Science     Hybrid Journal   (Followers: 5)
CERN IdeaSquare Journal of Experimental Innovation     Open Access   (Followers: 3)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 14)
ChemSusChem     Hybrid Journal   (Followers: 7)
China Communications     Full-text available via subscription   (Followers: 7)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
CIN Computers Informatics Nursing     Full-text available via subscription   (Followers: 11)
Circuits and Systems     Open Access   (Followers: 15)
Clean Air Journal     Full-text available via subscription   (Followers: 1)
CLEI Electronic Journal     Open Access  
Clin-Alert     Hybrid Journal   (Followers: 1)
Cluster Computing     Hybrid Journal   (Followers: 1)
Cognitive Computation     Hybrid Journal   (Followers: 4)
COMBINATORICA     Hybrid Journal  
Combinatorics, Probability and Computing     Hybrid Journal   (Followers: 4)
Combustion Theory and Modelling     Hybrid Journal   (Followers: 14)
Communication Methods and Measures     Hybrid Journal   (Followers: 12)
Communication Theory     Hybrid Journal   (Followers: 20)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Algebra     Hybrid Journal   (Followers: 3)
Communications in Computational Physics     Full-text available via subscription   (Followers: 2)
Communications in Partial Differential Equations     Hybrid Journal   (Followers: 3)
Communications of the ACM     Full-text available via subscription   (Followers: 52)
Communications of the Association for Information Systems     Open Access   (Followers: 16)
COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering     Hybrid Journal   (Followers: 3)
Complex & Intelligent Systems     Open Access   (Followers: 1)
Complex Adaptive Systems Modeling     Open Access  
Complex Analysis and Operator Theory     Hybrid Journal   (Followers: 2)
Complexity     Hybrid Journal   (Followers: 6)
Complexus     Full-text available via subscription  
Composite Materials Series     Full-text available via subscription   (Followers: 8)
Computación y Sistemas     Open Access  
Computation     Open Access  
Computational and Applied Mathematics     Hybrid Journal   (Followers: 2)
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2)
Computational and Mathematical Organization Theory     Hybrid Journal   (Followers: 2)
Computational and Structural Biotechnology Journal     Open Access   (Followers: 2)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Astrophysics and Cosmology     Open Access   (Followers: 1)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 11)
Computational Chemistry     Open Access   (Followers: 2)
Computational Cognitive Science     Open Access   (Followers: 2)
Computational Complexity     Hybrid Journal   (Followers: 4)
Computational Condensed Matter     Open Access  
Computational Ecology and Software     Open Access   (Followers: 9)
Computational Economics     Hybrid Journal   (Followers: 9)
Computational Geosciences     Hybrid Journal   (Followers: 15)
Computational Linguistics     Open Access   (Followers: 23)
Computational Management Science     Hybrid Journal  
Computational Mathematics and Modeling     Hybrid Journal   (Followers: 8)
Computational Mechanics     Hybrid Journal   (Followers: 5)
Computational Methods and Function Theory     Hybrid Journal  
Computational Molecular Bioscience     Open Access   (Followers: 2)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Particle Mechanics     Hybrid Journal   (Followers: 1)
Computational Research     Open Access   (Followers: 1)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computational Science and Techniques     Open Access  
Computational Statistics     Hybrid Journal   (Followers: 14)
Computational Statistics & Data Analysis     Hybrid Journal   (Followers: 30)
Computer     Full-text available via subscription   (Followers: 94)
Computer Aided Surgery     Hybrid Journal   (Followers: 6)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 8)
Computer Communications     Hybrid Journal   (Followers: 16)
Computer Engineering and Applications Journal     Open Access   (Followers: 5)
Computer Journal     Hybrid Journal   (Followers: 9)
Computer Methods in Applied Mechanics and Engineering     Hybrid Journal   (Followers: 23)
Computer Methods in Biomechanics and Biomedical Engineering     Hybrid Journal   (Followers: 12)
Computer Methods in the Geosciences     Full-text available via subscription   (Followers: 2)
Computer Music Journal     Hybrid Journal   (Followers: 19)

        1 2 3 4 5 6 | Last

Journal Cover AEU - International Journal of Electronics and Communications
  [SJR: 0.318]   [H-I: 36]   [8 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1434-8411
   Published by Elsevier Homepage  [3177 journals]
  • Dynamic analysis of a unique jerk system with a smoothly adjustable
           symmetry and nonlinearity: Reversals of period doubling, offset boosting
           and coexisting bifurcations
    • Authors: A. Nguomkam Negou; J. Kengne
      Pages: 1 - 19
      Abstract: Publication date: June 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 90
      Author(s): A. Nguomkam Negou, J. Kengne
      We investigated the dynamics of a novel jerk system generalized with a single parametric nonlinearity in the form φ k ( x ) = 0.5 ( exp ( kx ) - exp ( - x ) ) . The form of nonlinearity is interesting in the sense that the corresponding circuit realization involves only off-the shelf electronic components such as resistors, semiconductor diodes and operational amplifiers. Parameter k (i.e. a control resistor) serves to smoothly adjust the shape of the nonlinearity, and hence the symmetry of the system. In particular, for k = 1 , the nonlinearity is a hyperbolic sine, and thus the system is point symmetric about the origin. For k ≠ 1 , the system is non-symmetric. To the best of the authors’ knowledge, this interesting feature is unique and has not yet been discussed in chaotic systems. The dynamic analysis of the model involves a preliminary study of basic properties such as the nature of the fixed point, the transitions to chaos (bifurcation diagrams), the phase portraits as well as the Lyapunov exponent diagrams. When monitoring the system parameters, some striking phenomena are found including period doubling cascade bifurcation, reverse bifurcations, merging crises, offset boosting, coexisting bifurcations and hysteresis. Several windows in the parameters’ space are depicted in which the novel jerk system displays a plethora of coexisting asymmetric and symmetric attractors (i.e. coexistence of two, three or four different attractors) depending only on the selection of initial states. The magnetization of state space due to the presence of multiple competing solutions is illustrated by means of basins of attraction. More importantly, multistability in the symmetry boundary is discussed by monitoring the bifurcation parameter k. Laboratory experimental results based on the suitably designed electronic analogue of the model confirm the numerical findings.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.04.003
      Issue No: Vol. 90 (2018)
  • An improved compact MIMO antenna for wireless applications with
           band-notched characteristics
    • Authors: Sanjeev Kumar; Ravi Kumar; Rajesh Kumar Vishwakarma; Kunal Srivastava
      Pages: 20 - 29
      Abstract: Publication date: June 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 90
      Author(s): Sanjeev Kumar, Ravi Kumar, Rajesh Kumar Vishwakarma, Kunal Srivastava
      A quad-element highly compact multiple input multiple output (MIMO) antenna with notched characteristics is presented for wireless applications. The notch band characteristic is obtained by integrated two-quarter wavelength folded strip resonators into the patch antenna. A combination of a modified T-shaped stub and complementary split ring resonator (CSRR) is used to enhance the isolation into the common ground plane. The VSWR bandwidth of designed antenna is 320 MHz (2.30–2.62 GHz) and 6.84 GHz (3.46–10.3 GHz) with minimum isolation of around 18 dB among its antenna elements. The envelope correlation coefficient is <0.03 with an overall size of 32 × 38 mm2.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.04.008
      Issue No: Vol. 90 (2018)
  • Circularly polarized co-designed filtering annular slot antenna
    • Authors: Jianxing Li; Xiaoke Zhang; Jianzhong Chen; Juan Chen; Kai Da Xu; Anxue Zhang
      Pages: 30 - 35
      Abstract: Publication date: June 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 90
      Author(s): Jianxing Li, Xiaoke Zhang, Jianzhong Chen, Juan Chen, Kai Da Xu, Anxue Zhang
      In this paper, a compact circularly polarized co-designed filtering annular slot antenna (ASA) is proposed. The antenna comprises a distributed capacitor-loaded annular slot radiator to produce circular polarization (CP) radiation, which is seamlessly integrated with a microstripline bandpass filter (BPF) to enhance out-of-CP-band suppression. Two tightly coupled arc branches protruding into the annular slot are used to provide the required perturbation capacitance. The filter is designed by employing three concentric arc-shaped coupled microstripline resonators. The ground plane is shared by the annular slot radiator and the filter to reduce size occupation. It is found that the proposed antenna can not only yield high frequency selectivity, but also obtain widened CP bandwidth under the assistance of the filtering circuit. An antenna prototype has been fabricated and measured, showing that the antenna achieves a 10 dB return loss impedance bandwidth of around 13.7%, enclosing a 3 dB axial ratio (AR) bandwidth of more than 10.6%. Details of design considerations and experimental results are presented and discussed.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.04.010
      Issue No: Vol. 90 (2018)
  • Triple band notched mushroom and uniplanar EBG structures based UWB
           MIMO/Diversity antenna with enhanced wide band isolation
    • Authors: Naveen Jaglan; Samir Dev Gupta; Ekta Thakur; Dinesh Kumar; Binod Kumar Kanaujia; Shweta Srivastava
      Pages: 36 - 44
      Abstract: Publication date: June 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 90
      Author(s): Naveen Jaglan, Samir Dev Gupta, Ekta Thakur, Dinesh Kumar, Binod Kumar Kanaujia, Shweta Srivastava
      Triple band-rejection MIMO/Diversity UWB antenna characteristics are described in this paper. Proposed antenna discards worldwide interoperability for microwave access WiMAX band from 3.3 to 3.6 GHz, wireless local area network WLAN band from 5 to 6 GHz and X-Band satellite downlink communication band from 7.1 to 7.9 GHz. Mushroom Electromagnetic Band Gap (EBG) structures helps to attain band notches in WiMAX and WLAN bands. Uniplanar plus shaped EBG structure is used for notch in X-band downlink satellite communication band. Decoupling strips and slotted ground plane are employed to develop the isolation among two closely spaced UWB monopoles. The individual monopoles are 90° angularly separated with stepped structure which helps to reduce mutual coupling and also contributes towards impedance matching by increasing current path length. Mutual coupling magnitude of more than 15 dB is found over whole UWB frequency range. The Envelope Correlation Coefficient is less than 0.02 over whole UWB frequency range.The variations in the notched frequency with the variations in mushroom EBG structure parameters are investigated.The antenna has been designed using FR-4 substrate and overall dimensions is (64 × 45 × 1.6) mm3.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.04.009
      Issue No: Vol. 90 (2018)
  • Quantitative assessment of wideband antenna geometry modifications for
           size-reduction-oriented design
    • Authors: Muhammad Aziz ul Haq; Slawomir Koziel
      Pages: 45 - 52
      Abstract: Publication date: June 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 90
      Author(s): Muhammad Aziz ul Haq, Slawomir Koziel
      Incorporation of various topological modifications to basic antenna structures is a common strategy in the context of size-reduction-oriented design. Modifications can be applied to the ground plane, the feed line, and/or antenna radiator, and may lead to achieving smaller physical dimensions of the antenna at hand. Unfortunately, various topology alteration options are normally reported on a case-to-case basis; systematic comparisons of different modification types are lacking in the literature. In this paper, thorough investigations of selected topological changes in terms of their effect on antenna size reduction are carried out. Numerical experiments are performed using two ultra-wideband monopoles. In order to ensure a fair comparison, for each antenna topology, all geometry parameters are rigorously optimized to obtain the minimum footprint while maintaining acceptable electrical performance. The results clearly indicate the advantage of feed line modifications (56% average physical size reduction) over a ground plane and radiator ones (43% and 2.15% respectively). Experimental validations confirming the numerical findings are also provided.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.04.007
      Issue No: Vol. 90 (2018)
  • An analysis of RCS for dual-band slotted patch antenna with a thin
           dielectric using shorted stubs metamaterial absorber
    • Authors: Dhawan Singh; Viranjay M. Srivastava
      Pages: 53 - 62
      Abstract: Publication date: June 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 90
      Author(s): Dhawan Singh, Viranjay M. Srivastava
      A dual-band slotted patch antenna with thin dielectric has been proposed for Ku–band applications. A rectangular patch with pair of bent slots at each side of center has been designed and resonant at 11.95 GHz and 14.25 GHz with respect to ITU standard. A dual resonance ultrathin metamaterial absorber (MMA) based on circular rings and shorted stubs operating at same frequency bands have been designed. Its behavior at an oblique angle of incidence and polarization sensitivity has been also observed. In this research work, it has been obtained that when dual–band slotted patch antenna is surrounded by proposed MMA structure, it significantly enhances in-band stealth capability of the antenna. The monostatic and bistatic RCS of the proposed design has been reduced significantly whilst maintaining and preserving the antenna radiation performance. This design finds its application in satellite and wireless communication.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.039
      Issue No: Vol. 90 (2018)
  • A miniaturized dual band Wilkinson power divider using capacitor loaded
           transmission lines
    • Authors: Parastoo Rostami; Saeed Roshani
      Pages: 63 - 68
      Abstract: Publication date: June 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 90
      Author(s): Parastoo Rostami, Saeed Roshani
      A miniaturized dual band Wilkinson power divider (WPD) with an ultra wideband harmonic suppression is proposed, in this paper. Capacitor loaded transmission lines (CLTL) are used in the proposed circuit. The proposed WPD has a significant size reduction more than 80% compared to a primary power divider. In the design procedure, values of the impedances and electrical length for all of the applied transmission lines and also applied lumped capacitors are analytically obtained. Results of fabricated power divider have a good agreement with simulated and show that, the insertion loss at two operating frequencies of 0.9 and 1.8 GHz are less than 0.1 dB and also a wide range of unwanted harmonics (3.1–10.6 GHz) has been achieved.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.04.014
      Issue No: Vol. 90 (2018)
  • Input impedance modeling of patch and semi-rectangular substrate
           integrated waveguide cavity hybrid antenna
    • Authors: Hamideh Dashti; Mohammad H. Neshati
      Pages: 1 - 5
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Hamideh Dashti, Mohammad H. Neshati
      A complete equivalent-circuit model of input impedance is developed for a hybrid antenna, which consists of a Half Mode Substrate Integrated Waveguide (HMSIW) resonator and a microstrip patch. An accurate circuit model is derived using Transmission Line (TL) model and lumped-element. The results based on the circuit modeling are presented and compared with those obtained using full-wave simulation. The proposed model, for the first time, clarifies fundamental characteristics of the input impedance of the hybrid antenna, which are verified by the results of a full-wave simulation and those obtained by measurement.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.013
      Issue No: Vol. 89 (2018)
  • A 5-bit 1.8 GS/s ADC-based receiver with two-tap low-overhead embedded DFE
           in 130-nm CMOS
    • Authors: Azad Mahmoudi; Pooya Torkzadeh; Massoud Dousti
      Pages: 6 - 14
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Azad Mahmoudi, Pooya Torkzadeh, Massoud Dousti
      Along with CMOS technology scaling, ADC-based serial link receivers have drawn growing interest in backplane communications but power dissipation of the ADC and complex digital equalizer in such digital receivers can be a limiting factor in high-speed applications. Implementing analog embedded equalization within the front-end ADC structure can potentially relax the ADC resolution requirement and reduces the complexity of the DSP which results in a more energy-efficient receiver. In this paper, the equivalence between the speculative comparisons of a loop-unrolling DFE and an ADC with non-uniform quantization levels is utilized to propose a novel ADC-based DFE receiver structure. The equivalency partially compensates for the power overhead imposed by loop-unrolling DFE. The 5-bit prototype receiver with two-tap embedded DFE is designed, laid out and simulated in a 130-nm CMOS process with 1.8 Gbps data rate. With embedded DFE disabled, the receiver achieves 4.57-bits ENOB and 1.77 pJ/conv.-step FOM. With 1.8-Gbps signaling across a 48-in FR4 channel, the two-tap DFE enabled receiver opens the completely closed eye and allows for a 0.26 UI timing margin at a BER of 10−9. The total active area is 0.21 mm2 and the ADC consumes 76 mW from a 1.2-V supply.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.005
      Issue No: Vol. 89 (2018)
  • Investigation of the characteristics of low-cost and lightweight horn
           array antennas with novel monolithic waveguide feeding networks
    • Authors: Abdullah Genc; Ibrahim Bahadir Basyigit; Bektas Colak; Selcuk Helhel
      Pages: 15 - 23
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Abdullah Genc, Ibrahim Bahadir Basyigit, Bektas Colak, Selcuk Helhel
      3D printed X-Ku band single horn antenna and 2 × 1 and 2 × 2 pyramidal horn array antennas with novel lightweight and monolithic waveguide feeding networks (WFNs) are proposed at 10–15 GHz for satellite communications and radar systems to increase the gain. Proposed novel fabrication method consists of two main steps that are to make the skeleton of horn array antenna from acrylonitrile butadiene styrene (ABS) thermoplastic via 3D printer and to perform copper plating over all surface of antenna by using the electroless plating and electroplating processes. The WFN structures with 3λ element spacing designed and realized by using WR75 waveguide T-junction, E-type bend, and UDR 120 flange. Qualitative agreement between measurement and simulation via CST Microwave Studio is obtained with max 1 dB due to high precision and surface roughness. The gains of array antennas are increased by about 1.5 dB and 3 dB, respectively compared to the single antenna. VSWRs of array antennas are 0.3 dB and 0.6 dB, respectively higher than the single one. In the study, proposed 3D printed components not only with 90% lighter weight than, but also with 80% cheaper than commercial products, and horn arrays with -40 dB cross-polarization values.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.024
      Issue No: Vol. 89 (2018)
  • Analysis of electromagnetic scattering from anisotropic cylindrical
           structures using state space method
    • Authors: N. Vaseghi; M.S. Abrishamian
      Pages: 24 - 33
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): N. Vaseghi, M.S. Abrishamian
      Scattering of the electromagnetic waves from anisotropic cylindrical structures (ACS) is investigated using an exact and analytical frequency domain method in the most general case. The state space approach is used for analyzing of wave propagation in cylindrical structures for the first time. The validity of the proposed method is verified for the anisotropic cylindrical structures which have closed-form solutions. Comparing the results obtained by closed-form solution, the proposed approach and other commonly used methods in literature shows that the method is accurate, fast and simple. The presented study is covered all practical considerations in the field of electromagnetic scattering from ACS's such as polarization and incident angle of excitations, the geometry and configuration of the structure. This comprehensiveness is one of the biggest advantages of the investigation. Regarding the applications of the state space method in parameters retrieval of planar structures, the present study can be effective as the first and basic step in opening a new way toward further studies on inverse scattering of the cylindrical structures consisting complex media.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.01.016
      Issue No: Vol. 89 (2018)
  • Modeling and optimization of EBG structure using response surface
           methodology for antenna applications
    • Authors: D. Helena Margaret; B. Manimegalai
      Pages: 34 - 41
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): D. Helena Margaret, B. Manimegalai
      Electromagnetic Bandgap (EBG) structures are widely used with microstrip antennas for improving antenna efficiency due to their ability to suppress surface waves. To have proper control of surface wave band-gap, it is necessary to have efficient models of the dispersion characteristics of EBG in the irreducible Brillouin zone. A new methodology for optimization of a modified mushroom EBG is presented, based on Response Surface Modeling (RSM) along with Design of Experiments (DoE). Four geometrical parameters which control the surface wave band gap namely the patch width (w), gap between the patches (2g), via radius(r) and the slot width(s) are considered as independent factors and DoE is carried out using Finite Element Analysis (FEA) simulation. The lower (F1) and upper (F2) frequencies of the band gap are extracted from the dispersion characteristics. Mathematical models for F1 and F2 are developed using non-linear regression analysis. Analysis of Variance (ANOVA) is used to study the effect of EBG parameters on the stop band frequencies. The optimum EBG parameters for a stop band in 5–8 GHz frequency range are determined and are found to be: patch width, 6.48 mm, gap, 0.49 mm, via radius, 0.25 mm and slot width, 0.48 mm. The statistical model is validated by experimental results.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.017
      Issue No: Vol. 89 (2018)
  • Performance enhancement of a compact wideband patch antenna array using
           EBG structures
    • Authors: Shahrokh Jam; Mojtaba Simruni
      Pages: 42 - 55
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Shahrokh Jam, Mojtaba Simruni
      In this paper, a compact wideband linear microstrip phased array antenna (MPAA) is proposed. To reduce the size of MPAA, a compact wideband aperture coupled microstrip patch antenna (MPA) is utilized as array element. Size reduction of the array element is performed through incorporating an interdigital capacitor (IDC) in the patch and a metamaterial (MTM) unit cell close to slot in the ground plane of the antenna. By cutting two vertical slits from the slot, further compacting of the slot in the ground plane of array element is obtained. By this technique dimensions of the patch and slot are reduced by 12.9% and 12.2%, respectively. Furthermore, dimensions of the MPAA are reduced through decreasing the spacing between array elements causing the antenna performance degradation. To overcome this shortage and improve the radiation characteristics of the proposed MPAA, an electromagnetic bandgap structure (EBG) is utilized. The effect of implementing EBG cells on the reflection coefficient of the elements in the MPAA during beam scanning is studied in details. The maximum measured gain, bandwidth and cross-polarization level of the fabricated MPAA are 13.3 dBi, 24.4% and −40 dB, respectively making it a good candidate for monopulse tracking radar applications. The measurement results confirm the simulation results.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.026
      Issue No: Vol. 89 (2018)
  • A low power current-reuse LC-VCO with an adaptive body-biasing technique
    • Authors: Tayebeh Azadmousavi; Esmaeil Najafi Aghdam
      Pages: 56 - 61
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Tayebeh Azadmousavi, Esmaeil Najafi Aghdam
      This work presents a low-power low-phase noise current-reuse LC voltage controlled oscillator (VCO) with an adaptive body-biasing technique that enhances the reliability of the proposed circuit under process, voltage, and temperature (PVT) variations. Furthermore, the supply voltage and power consumption of the proposed VCO are reduced by the start-up oscillation condition that is provided by the adaptive body-biased circuit. This property is in fact very interesting from the power management perspective. The proposed VCO works at carrier frequency of 1.8 GHz and draws the power of only 306 µW from a 0.9 V supply. It achieves phase noise of −123.36 dBc/Hz at 1 MHz offset and provides a figure-of-merit (FoM) of −193.61 dBc/Hz. The post-layout simulation results of designed VCO in 0.18 µm standard CMOS technology confirm the effectiveness of the proposed circuit.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.022
      Issue No: Vol. 89 (2018)
  • An efficient channel assignment algorithm for multicast wireless mesh
    • Authors: Wenxiao Shi; Shaobo Wang; Zhuo Wang; Endong Wang
      Pages: 62 - 69
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Wenxiao Shi, Shaobo Wang, Zhuo Wang, Endong Wang
      Multicast can enhance the performance of wireless mesh networks (WMNs) effectively, which has attracted great attentions in recent years. However, multicast communication in WMNs requires efficient channel assignment strategy to reduce the total network interference and maximize the network throughput. In this paper, the concept of local multicast is proposed to measure interference and solve hidden channel problem in multicast communication. Basing on the concept, we propose a channel assignment algorithm considering the interference of local multicast and forwarding weight of each node (LMFW). The algorithm fully considers partially overlapped channels and orthogonal channels to improve the network performance. Simulations show that the proposed algorithm can reduce interference and improve network capacity of WMNs.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.023
      Issue No: Vol. 89 (2018)
  • Robust TFET SRAM cell for ultra-low power IoT applications
    • Authors: Sayeed Ahmad; Naushad Alam; Mohd. Hasan
      Pages: 70 - 76
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Sayeed Ahmad, Naushad Alam, Mohd. Hasan
      Design of ultra-low power SRAM with robust operation for Internet of Thing (IoT) sensor node is a new challenge. In this work, a novel 9T TFET based SRAM bit cell is proposed. The analysis and simulation results demonstrate that the proposed cell eliminates read disturb issue and outperforms the state-of-the-art 9T TFET bit cell in terms of static and dynamic write performance. The presented circuit topology incorporates power cut-off and write ‘0’ only technique to enhance the write performance. The proposed cell exhibits 1.15× higher write margin (WM), 25% lower write delay, consumes 73% (57%) lower write (average) energy, 7% smaller standby leakage power measured at VDD = 0.3 V. The proposed cell also shows significant improvement in the read/write performance as compared with existing 7T and 8T TFET cells. Our proposed cell also eliminates half-select disturb issue to make it suitable for bit-interleaving architecture that is a must for enhanced soft error immunity.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.029
      Issue No: Vol. 89 (2018)
  • Multiband integrated wideband antenna for bluetooth/WLAN applications
    • Authors: Kunal Srivastava; Ashwani Kumar; Binod. K. Kanaujia; Santanu Dwari; Sachin Kumar
      Pages: 77 - 84
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Kunal Srivastava, Ashwani Kumar, Binod. K. Kanaujia, Santanu Dwari, Sachin Kumar
      The paper presents an O-shape multiband monopole antenna design (Antenna-I) with different patch orientations; 90-degree (Antenna-II) and 180-degree (Antenna-III). The proposed Antenna-I is a multiband integrated wideband monopole antenna with two integrated bands supporting modern wireless services such as Bluetooth and Wireless Local Area Network (WLAN) in addition to wideband covering upper Ultra-wideband (UWB) frequencies. The first band ranges from 2.05 to 3.05 GHz and second band from 3.65 to 3.92 GHz in the −10 dB impedance bandwidth range. The wideband covers upper frequencies (5.24–10.75 GHz) in the range of Ultra-wideband. Antenna-II resonates at 2.38 GHz (2.11–2.90 GHz) covering Bluetooth band and upper UWB region 5.18–10.86 GHz. The proposed Antenna-III covers 1.96–2.33 GHz and 3.74–10.46 GHz frequency bands. The antenna gain at integrated band is around 2.8 dBi and varies from 4 dBi to 8.03 dBi in the UWB region. The measured fidelity factor is 0.89 for face to face and 0.82 for side by side. Measured results are presented to validate the antenna performances.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.027
      Issue No: Vol. 89 (2018)
  • A sub-wavelength polarization sensitive band-stop FSS with wide angular
           response for X- and Ku-bands
    • Authors: Saeed Abbasi; Javad Nourinia; Changiz Ghobadi; Mohsen Karamirad; Bahman Mohammadi
      Pages: 85 - 91
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Saeed Abbasi, Javad Nourinia, Changiz Ghobadi, Mohsen Karamirad, Bahman Mohammadi
      A sub-wavelength second-order band-stop frequency selective surface (FSS) is presented. The single layer FSS has a band reject operating mode for TE- and TM-polarizations incidence. Miniaturization of the FSS unit cell is achieved by coupling two resonators separated by single FR4 substrate. The unit cell size of the proposed FSS is 0.25λ 0 × 0.25λ 0, which λ 0 is the free space wavelength at the center frequency (10 GHz). As experimental results proved, the proposed FSS has a great angle independence up to 60°. An equivalent circuit model is illuminated the operating principle of designed FSS. The validity of FSS is obtained by comparing experimental results and full-wave simulations.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.018
      Issue No: Vol. 89 (2018)
  • A new multi-objective distributed fuzzy clustering algorithm for wireless
           sensor networks with mobile gateways
    • Authors: Maryam Abdolkarimi; Sepideh Adabi; Arash Sharifi
      Pages: 92 - 104
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Maryam Abdolkarimi, Sepideh Adabi, Arash Sharifi
      In the clustered wireless sensor networks (WSNs) studied, each cluster head (CH) transmits aggregated data from cluster members to the static base station by means of intermediate communication nodes in name mobile gateways. In order to reduce energy consumption along with reducing delays in packet delivery in the mentioned WSNs, two approaches are proposed: (1) designing a completely distributed fuzzy system to determine the eligibility of the node for being CH with two input factors, namely the general state of a sensor node in the WSN (GSoSN) and location of a sensor node relative to mobile gateway nodes (LoSNRtMG). By defining two early discussed factors, not only the accuracy of decision making in selecting the CH node enhances but also the computation overhead decreases; and (2) reducing communication overhead by applying the linear prediction method to estimate the next locations of the moving gateway nodes instead of periodical broadcasting of their location messages. The experimental results demonstrate that the proposed idea has better performance in terms of reducing both energy consumption and delays in packet delivery metrics.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.020
      Issue No: Vol. 89 (2018)
  • Analysis and design of a new COA-based current-mode instrumentation
           amplifier with robust performance against mismatches
    • Authors: Leila Safari; Shahram Minaei; Giuseppe Ferri; Vincenzo Stornelli
      Pages: 105 - 109
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Leila Safari, Shahram Minaei, Giuseppe Ferri, Vincenzo Stornelli
      In this paper, analysis and design of a new current-mode instrumentation amplifier (CMIA) circuit is presented. The proposed circuit employs two Current Operational Amplifiers (COA) as active building blocks, one resistor and two transistors operating as variable resistors to electronically control the differential-mode gain. The main feature of the proposed CMIA is that unlike most previously reported CMIAs, its CMRR has negligible sensitivity to mismatches. In addition, in the proposed circuit both active building blocks operate in negative feedback loop which results in an overall enhanced performance. SPICE simulation results using 0.18 μm TSMC CMOS parameters and supply voltage of ±0.9 V show a constant CMRR of about 51 dB regardless of mismatches and wide bandwidth ranging from 14.8 MHz to about 3 MHz for differential-mode gains between 3 and 18 dB, respectively.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.021
      Issue No: Vol. 89 (2018)
  • A compact CPW-based dual-band filter using modified complementary split
           ring resonator
    • Authors: Dilip Kumar Choudhary; Raghvendra Kumar Chaudhary
      Pages: 110 - 115
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Dilip Kumar Choudhary, Raghvendra Kumar Chaudhary
      In this paper, a compact coplanar waveguide (CPW) based dual-band bandpass filter has been proposed. The modified complementary split ring resonator (CSRR) structure at CPW ground plane is investigated for designing of dual-band bandpass filter with minimum insertion loss. The zeroth order resonance (ZOR) frequency depends on shunt parameter due to open ended boundary condition. The dual-band bandpass filter with return loss 21 and 20 dB, insertion loss 0.5 and 0.4 dB at 1.8 and 3.2 GHz, respectively, are simulated and measured. The measured 3 dB fractional bandwidths are 92.7% and 18.8% with respect to their centre frequencies of passbands. The simulated and measured results are showing good agreement in the passband. The electrical size of designed filter is 0.10λ 0 × 0.09λ 0 × 0.007λ 0, where λ 0 is the free space wavelength at the resonance frequency of first pass band. It is suitable for a global system for mobile (GSM) and long term evolution (LTE) in different service bands of 900, 1800, 1900 and 2300 MHz wireless communication applications.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.032
      Issue No: Vol. 89 (2018)
  • Gysel power divider with efficient second and third harmonic suppression
           using one resistor
    • Authors: Elham Moradi; Ali-Reza Moznebi; Kambiz Afrooz; Masoud Movahhedi
      Pages: 116 - 122
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Elham Moradi, Ali-Reza Moznebi, Kambiz Afrooz, Masoud Movahhedi
      A Gysel power divider/combiner with the second and third harmonic suppression using one resistor is proposed. Three open-circuit stubs are used to suppress the second and third harmonics. To calculate the values of the design parameters, the closed-form design equations are derived. A sample power divider is designed at 1 GHz to verify the design procedure. The measured results are nearly in agreement with the simulation results. The proposed Gysel power divider provides a high power-handling advantage over Wilkinson power divider. Moreover, it has a fractional bandwidth of 30% and harmonic suppression of 25 and 35 dB at the second and third harmonics, respectively.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.011
      Issue No: Vol. 89 (2018)
  • A novel monostatic concurrent multiband radar front-end architecture and
           its dual-band implementation
    • Authors: Mingxing Li; Yongle Wu; Lingxiao Jiao; Yuanan Liu
      Pages: 123 - 130
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Mingxing Li, Yongle Wu, Lingxiao Jiao, Yuanan Liu
      This paper proposes a novel monostatic concurrent multiband radar front-end architecture that can work in several independent bands simultaneously. Compared with the conventional single-band radar, multiband radar has the potential to support different modulation modes in independent frequency bands and multi-functional integration, and has a good ability to adapt to complex electromagnetic environment and flexible applications. In order to demonstrate the validity of this proposed multiband radar front-end architecture, the corresponding dual-band radar and two single-band radar prototypes are fabricated and measured. A good agreement of measured results between the dual-band and two single-band radar front-ends validates the effectiveness and reliability of the proposed new radar architecture.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.030
      Issue No: Vol. 89 (2018)
  • A new hidden chaotic attractor with extreme multi-stability
    • Authors: Sajad Jafari; Atefeh Ahmadi; Abdul Jalil M. Khalaf; Hamid Reza Abdolmohammadi; Viet-Thanh Pham; Fawaz E. Alsaadi
      Pages: 131 - 135
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Sajad Jafari, Atefeh Ahmadi, Abdul Jalil M. Khalaf, Hamid Reza Abdolmohammadi, Viet-Thanh Pham, Fawaz E. Alsaadi
      The topic of hidden attractors is a very hot topic in nonlinear dynamics. Multi-stability is another important topic in that area. One recent important category of multi-stable systems is “systems with extreme multi-stability”. In this paper we introduce a new five-dimensional chaotic system with both hidden attractors and extreme multi-stability. Such systems are very rare in literature. Also, we show its feasibility by the help of electronic circuit implementation.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.037
      Issue No: Vol. 89 (2018)
  • A novel electronically controlled Schmitt trigger with clockwise and
           anticlockwise hystereses
    • Authors: Bhartendu Chaturvedi; Atul Kumar
      Pages: 136 - 145
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Bhartendu Chaturvedi, Atul Kumar
      A novel circuit of Schmitt trigger employing a prototype of dual-X current conveyor transconductance amplifier and one grounded resistor is proposed in this paper. The main focus of the paper is towards the practicality of the proposed Schmitt trigger using the prototype of DXCCTA which is realized using commercially available ICs. The proposed circuit is easily cascadable. Both clockwise and anticlockwise hystereses are achievable simultaneously from the proposed circuit. The threshold levels and amplitudes of output currents are independently and electronically controllable. The non-ideal and parasitic studies of the proposed Schmitt trigger are investigated. Moreover, the application of Schmitt trigger as zero crossing detector is explored which enriches the applicability of the proposed circuit. Experimental results are depicted to verify the proposed Schmitt trigger circuit. Measured results show the good tuning of amplitude of output current for a wide range of 50 µA to 1.5 mA.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.015
      Issue No: Vol. 89 (2018)
  • Top-down random channel generator for the narrowband power line
    • Authors: Héla Gassara; Fatma Rouissi; Adel Ghazel
      Pages: 146 - 152
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Héla Gassara, Fatma Rouissi, Adel Ghazel
      This paper proposes a random channel generator for the narrowband power line communication (PLC). Based on the top-down approach, an analytical formulation with a limited set of parameters is established for the PLC channel transfer function in the frequency band below 500 kHz. Then, the extracted parameters deduced from measurements are fitted with proper distribution functions. The top-down random channel generator is validated through the comparison between measured and generated channels in terms of time–frequency characterization metrics, especially the average channel attenuation, the root mean square (RMS) delay spread and the coherence bandwidth. Obtained results show the good agreement between the proposed modeled channels and the experimental ones with very close mean values and distributions of the main metrics.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.003
      Issue No: Vol. 89 (2018)
  • Separable transmit beampattern design for MIMO radars with planar
           colocated antennas
    • Authors: Alireza Pakdaman; Hamidreza Bakhshi
      Pages: 153 - 159
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Alireza Pakdaman, Hamidreza Bakhshi
      Multiple-input multiple-output (MIMO) radar transmit beampattern design for one-dimensional arrays has been widely studied in literatures. In this paper, transmit beampattern design is considered for two-dimensional (2D) arrays. As the size of the array is increased, the computational complexity and time for pattern optimization are increased drastically. To overcome these problems, we introduced the conditions upon which the 2D beampattern design for uniform rectangular arrays (URA) can be achieved via the product of two perpendicular transmit beampatterns of uniform linear arrays (ULA). The transmit beampattern design is accomplished under special characteristics such as minimum integrated sidelobe level or special 3 dB beamwidth in azimuth and elevation with much lower computation time.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.028
      Issue No: Vol. 89 (2018)
  • Absorptive frequency selective surface with switchable passband
    • Authors: Qihui Zhou; Peiguo Liu; Ke Wang; Hanqing Liu; Dingwang Yu
      Pages: 160 - 166
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Qihui Zhou, Peiguo Liu, Ke Wang, Hanqing Liu, Dingwang Yu
      An active absorptive frequency selective surface (AFSS) is proposed in this paper, which is comprised of a switchable bandpass screen and a periodic resistive surface separated by a foam layer. The switchable bandpass screen embedded with PIN diodes achieves the shift of transmission and reflection in the operating band by controlling the bias voltage. The resistive surface consists of several resonance loops inserted with lumped resistors. At the both sides of the operating band, the entire AFSS performs as an absorber with the switchable bandpass screen playing the role of ground plane. The absorption bands range from 1.3 to 6 GHz and 9.5 to 12.5 GHz with a transmission window at 8.2 GHz, which can be removed with little impact on the absorbing properties. A prototype of the structure is fabricated to verify the numerical simulation. Moreover, the simulated results also show that the proposed AFSS exhibits stable performance for different polarized waves due to the symmetric structure.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.034
      Issue No: Vol. 89 (2018)
  • Adaptive spatial modulation and thresholds optimization for MIMO systems
           in correlated Rayleigh channels
    • Authors: Xiangbin Yu; Qing Pan; Yang Li; Yaping Hu; Tao Liu
      Pages: 167 - 173
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Xiangbin Yu, Qing Pan, Yang Li, Yaping Hu, Tao Liu
      Spatial modulation (SM) is a simple and spectral efficient modulation technique that has received much interest recently. In this paper, an adaptive SM (ASM) scheme is presented by combining adaptive modulation with conventional SM. The performance of ASM is analyzed in spatially correlated Rayleigh fading channels. In order to reduce the computational complexity of average bit error rate (BER), an approximate expression of error probability of the antenna index estimation, which contributes one of two components of the average BER, is derived by using the fitting method and matches well with simulation results in the SNR range of interest. With the above results, the closed-form spectrum efficiency (SE) and overall average BER are obtained, respectively. Besides, the optimized switching thresholds for maximizing SE under an average BER constraint are achieved by means of the Karush Kuhn Tucker conditions, and the resultant SE performance can be improved greatly when compared to the ASM system with fixed thresholds. Simulations indicate that the theoretical SE and BER are effective and agree well with the corresponding simulations. Moreover, the SE and BER performance of ASM under spatially correlated channel are poorer than those under spatially independent channel because of the influence of spatial correlation.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.04.001
      Issue No: Vol. 89 (2018)
  • On the cyclostationarity of Universal Filtered Multi-Carrier UFMC
    • Authors: Kawtar Zerhouni; Raja Elassali; Fouzia Elbahhar; Khalid Elbaamrani; Noureddine Idboufker
      Pages: 174 - 180
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Kawtar Zerhouni, Raja Elassali, Fouzia Elbahhar, Khalid Elbaamrani, Noureddine Idboufker
      In order to meet the explosion of connected devices with their heterogeneous applications, the upcoming 5G systems focus on the design of spectrally efficient waveforms. Universal Filtered Multicarrier (UFMC) is one of the major waveforms contenders that offers low out of band emissions, compatibility with the existing Multiple Input Multiple Output techniques as well as multiple services support. In this paper, we propose to couple UFMC with Cognitive Radio (CR) to make better use of the available spectral resources. To perform spectrum sensing for the CR, we rely on cyclostationary detection. UFMC cyclostationarity characteristics have not been researched before. Hence in the present work, we first derive the explicit theoretical m-th order cyclic cumulants of UFMC, considering a multipath channel, frequency and timing offsets. Our analysis reveals that the per-subband filtering used in this waveform produces distinctive cyclostationary signatures. Then we exploit these signatures for signal detection. The obtained results are compared to those of the well studied Orthogonal Frequency Division Multiplexing (OFDM). Detection probability of UFMC outperforms the one of OFDM specially when the used Cyclic Prefix (CP) is low.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.016
      Issue No: Vol. 89 (2018)
  • Efficient compressive sensing based sparse channel estimation for 5G
           massive MIMO systems
    • Authors: Imran Khan; Dhananjay Singh
      Pages: 181 - 190
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Imran Khan, Dhananjay Singh
      Massive MIMO (multiple-input-multiple-output) is one of the key technologies of 5G mobile cellular networks, which can form a huge antenna array by providing a large number of antennas at the cell base station. It will greatly improve the channel capacity and spectrum utilization and has become a hotspot in the field of wireless communications in recent years. Aiming at the high complexity of channel estimation algorithm for massive MIMO system, a sparse channel estimation algorithm with low complexity is proposed based on the inherent sparsity of wireless communication channel. The algorithm separates the channel taps from the noise space on the basis of the traditional discrete Fourier transform (DFT) channel estimation, so that the channel estimation only needs to calculate the part of the channel tap, so the computational complexity of the algorithm is greatly reduced. The simulation results show that the proposed algorithm can achieve near minimum mean square error (MMSE) performance while maintaining low complexity. Moreover, the Bit Error Rate and Inter-Cell Interference also indicates that the proposed improved algorithm shows better overall performance than the conventional algorithms which makes it suitable from practical perspective.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.038
      Issue No: Vol. 89 (2018)
  • Optimized mobile sink based grid coverage-aware sensor deployment and link
           quality based routing in wireless sensor networks
    • Authors: Seema Dahiya; P.K. Singh
      Pages: 191 - 196
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 89
      Author(s): Seema Dahiya, P.K. Singh
      Mobile sink (MS) has been used in wireless sensor networks (WSN) to increase the network lifetime by changing the location over time. The major quality of service given by WSN is coverage energy consumption (EC) and network lifetime. There are many methods implemented for enhance the coverage hole restoration and reduce the EC. We propose a novel MSCOLER (MS based Coverage Optimization and Link-stability Estimation Routing) protocol for Optimal Coverage restoration and Link stability Estimation. An optimization algorithm is used to optimize the coverage hole and move the redundant node besides the hole. During the routing process, link quality based routing is used to discover the relay nodes with the estimation of link stability to enhance the entire network lifetime and practically make the perfect transmission distance for energy saving. Experimental results demonstrate that proposed protocol can solve the coverage restoration problem, decrease the EC and reduce the network lifetime. The performance is evaluated regarding Average of residual energy (ARE), Receiving packets ratio (RPR), Moving energy consumption (MEC), Network lifetime (NL), Percentage of coverage (%C) and Average Energy Consumption (AEC).

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.031
      Issue No: Vol. 89 (2018)
  • Modelling and validation of microwave LPF using modified rectangular split
           ring resonators (SRR) and defected structures
    • Authors: Sarbani Sen; Tamasi Moyra; Dwipjoy Sarkar
      Pages: 1 - 10
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 88
      Author(s): Sarbani Sen, Tamasi Moyra, Dwipjoy Sarkar
      We propose a design of lowpass filter (LPF) using modified rectangular split ring resonator (SRR) that acts as a unit cell of metamaterials. Initially, a conventional LPF of 4.5 GHz is designed and the low impedance line is replaced to produce a sharp cut-off with a modified SRR structure. A brief parametric study is done to establish a relationship between the inner perimeter of the SRR to the cut-off frequency of the proposed LPF. Same study is also done for the outer perimeter. Using this relationship, another LPF of 2.4-GHz cut-off frequency is obtained. Defected ground structures (DGS) and microstrip structures (DMS) are incorporated with the 2.4-GHz LPF structure for the removal of harmonics and better pass-band characteristics. The IE3D simulation results and the circuit simulation results are in good agreement with the measured results. The obtained structure can thus be used for several useful applications such as in Bluetooth, Wi-Fi, cordless phones, computers, and other wireless communication devices.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.02.009
      Issue No: Vol. 88 (2018)
  • Two new analog multipliers/dividers employing single current differencing
           buffer amplifier
    • Authors: Suvajit Roy; Tapas Kumar Paul; Saikat Maiti; Radha Raman Pal
      Pages: 11 - 19
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 88
      Author(s): Suvajit Roy, Tapas Kumar Paul, Saikat Maiti, Radha Raman Pal
      This paper presents two new analog multipliers/dividers using a new universal active element, called the current differencing buffered amplifier (CDBA). The reported circuits are suitable for monolithic chip realization for use in battery-powered, portable electronic equipments. The circuits can be used as a multiplier and divider without changing circuit topologies. The workability of the proposed configurations is tested through different applications with PSPICE simulations using TSMC 0.35 μm CMOS process parameters. The simulated results show that: for ±2.5 V power supply, the total harmonic distortions are less than 3.1% and 2.25% for the first and second configuration respectively. It also shows that the −3 dB bandwidths are 59.09 MHz and 68.55 MHz and static power dissipations are 0.28 mW and 0.23 mW respectively. The sensitivity of the output of the circuits is low with respect to temperature variations.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.002
      Issue No: Vol. 88 (2018)
  • A novel digital programmable multi-scroll chaotic system and its
           application in FPGA-based audio secure communication
    • Authors: De Chang; Zhijun Li; Mengjiao Wang; Yicheng Zeng
      Pages: 20 - 29
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 88
      Author(s): De Chang, Zhijun Li, Mengjiao Wang, Yicheng Zeng
      In recent years, information security is an increasingly vital problem. In this paper, we introduce an audio encryption scheme based on the novel digital programmable multi-scroll chaotic system. The chaotic system is described by three differential equations with piecewise nonlinear functions. More interesting, the number of scrolls of the proposed chaotic system is programmable and can be changed real-time. The system is discretized by Euler method and the digital implementation is provided. Based on this, a chaos-based audio secure communication system is developed by using feedback drive-response synchronization. The number of scrolls changes randomly by extracting control signals from the encrypted data. A series of security analyses are applied, showing good performance of the method. The system is verified through experiment on an Altera Cyclone IV FPGA platform, which effectively confirms the theoretical analysis.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.007
      Issue No: Vol. 88 (2018)
  • A unified modeling approach for DC-DC converters based on the three-state
           switching cell
    • Authors: Wesley H. Maciel; José Augusto R. Carvalho; Fernando L. Tofoli
      Pages: 30 - 37
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 88
      Author(s): Wesley H. Maciel, José Augusto R. Carvalho, Fernando L. Tofoli
      This paper proposes a general small-signal model for the representation of dc-dc converters based on the three-state switching cell (3SSC) operating in continuous conduction mode (CCM). Even though such power electronic converters present distinct behaviors depending on the duty cycle range i.e. 0 < D < 0.5 and 0.5 < D < 1, the developed analysis effectively shows that the derived model is valid in either case. An approach similar to the PWM (pulse width modulation) switch is employed, being this a fair, simple, and straightforward technique if compared with other similar ones e.g. average state-space modeling. Dc and ac small-signal models can then be obtained in order to provide relevant expressions associated to the converters e.g. the static gain and several transfer functions used in the implementation of closed-loop control. A dc-dc buck converter is also investigated, whose model is properly represented by mathematical expressions that are validated by simulation tests for both operating conditions of the 3SSC.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.009
      Issue No: Vol. 88 (2018)
  • Miniaturized wideband dual linearly and circularly polarized printed
           square slot antenna for multiradio wireless systems
    • Authors: Ashok Kumar; Jitendra Kumar Deegwal; Mahendra Mohan Sharma
      Pages: 44 - 51
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 88
      Author(s): Ashok Kumar, Jitendra Kumar Deegwal, Mahendra Mohan Sharma
      A dual symmetrical coplanar waveguide (CPW)-fed small size wideband printed square slot antenna (SSA) with dual linearly and circularly polarized radiation capability is presented. The antenna is composed using a square slot, two symmetrical orthogonal CPW feed lines connected to horizontal and vertical arm of L-shaped radiator, an embedded parasitic inverted-L strip at the lower left corner of the square ground slot and engraving slots in the ground plane. Circular polarization (CP) is achieved due to two orthogonal CPW feed lines and a common L-shaped radiator. Isolation between ports is improved by engraving slots at the lower left corner of ground plane and embedded parasitic inverted-L strip. The sense of dual-polarization can be changed in pass-band by changing the port excitation. Measured antenna reveals that an 84.4% (4.6 GHz, 3.15–7.75 GHz) −10 dB impedance bandwidth (IBW) and about 33% (2.03 GHz, 5.12–7.15 GHz) 3-dB axial ratio bandwidth (ARBW). Isolation between ports <−16 dB is achieved over usable CP band.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.006
      Issue No: Vol. 88 (2018)
  • Secure communication with a chaotic system owning logic element
    • Authors: Serdar Çiçek; Uğur Erkin Kocamaz; Yılmaz Uyaroğlu
      Pages: 52 - 62
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 88
      Author(s): Serdar Çiçek, Uğur Erkin Kocamaz, Yılmaz Uyaroğlu
      In recent years, various chaotic systems have been introduced in literature to be used in different branches of science. In the field of secure chaotic communication, more complex chaotic systems are proposed, such as high dimensional (4D, 5D), multi-scroll, surface equilibrium point, to enhance communication security level. In this study, a chaotic system owning logic element is used for increasing the level of security of chaotic communication system, which has not been previously implemented for this purpose in the literature. The used chaotic system includes signum functions, maximum function and absolute operation term. Also, there are analog devices and digital device in the electronic circuit of this chaotic system. These properties increase the complexity of the chaotic system and the security level. Sliding mode control method is preferred for the synchronization part of the secure communication. In this regard, numerical analysis and electronic circuit design of the secure chaotic communication system by using the chaotic system owning logic element have been performed successfully.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.008
      Issue No: Vol. 88 (2018)
  • Elliptical slot loaded partially segmented circular monopole antenna for
           super wideband application
    • Authors: Piyush Okas; Anand Sharma; Gourab Das; Ravi Kumar Gangwar
      Pages: 63 - 69
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 88
      Author(s): Piyush Okas, Anand Sharma, Gourab Das, Ravi Kumar Gangwar
      This article inspects partially segmented circular monopole with elliptical slot for super wideband applications. Two significant characteristics of proposed antenna design are: (i) partially segmented circular monopole, notch loaded elliptical ground plane along with tapered microstrip line provides super wide bandwidth; (ii) elliptical slot in between the partially segmented circular monopole reduces the lower operating frequency (1.07 GHz–0.96 GHz), which in turn enhance the bandwidth dimension ratio (BDR). For verifying the simulated outcomes, antenna prototype is practically constructed and measured. The proposed antenna design attains frequency range from 0.96 GHz to 10.9 GHz (VSWR < 2) with bandwidth ratio of 11.35:1 and percentage bandwidth of 167.22%. Bandwidth dimension ratio of proposed radiator is 6975.22. Frequency as well as time domain analysis of proposed radiator approves its applicability for super wideband wireless applications.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.004
      Issue No: Vol. 88 (2018)
  • A novel dual-band tunable notch filter with controllable center
           frequencies and bandwidths
    • Authors: Samaneh Sedighi Maragheh; Massoud Dousti; Mehdi Dolatshahi; Behbod Ghalamkari
      Pages: 70 - 77
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 88
      Author(s): Samaneh Sedighi Maragheh, Massoud Dousti, Mehdi Dolatshahi, Behbod Ghalamkari
      This article proposes a new dual-band tunable bandstop filter. This tunable filter is composed of two separate parts, the transmission line, and coupled stubs that each connect to three varactors. The center frequency and bandwidth in each band can be controlled individually. Moreover, the LC equivalent circuit of the proposed filter is calculated, and the results are simulated. In the proposed filter, the simulations show that the first stopband can be tuned in a frequency range from 1.2 to 1.9 GHz with 10-dB absolute bandwidth 310 ± 30 MHz, whereas the second stopband varies from 2.5 to 3.3 GHz with the 10-dB absolute bandwidth 720 ± 20 MHz. These two stopbands can also be tuned independently. Furthermore, the bandwidth of each fixed center frequency can be changed easily. The fabricated proposed filter validates the simulation results. The compact filter has an effective size of 9 × 27.5 mm2.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.02.018
      Issue No: Vol. 88 (2018)
  • A reconfigurable parasitic antenna with continuous beam scanning
           capability in H-plane
    • Authors: Vikas V. Khairnar; Bhushan V. Kadam; C.K. Ramesha; Lucy J. Gudino
      Pages: 78 - 86
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 88
      Author(s): Vikas V. Khairnar, Bhushan V. Kadam, C.K. Ramesha, Lucy J. Gudino
      A reconfigurable microstrip Yagi antenna is proposed to realize continuous and improved beam scanning from −40 ° to 40 ° in the H-plane. The antenna is designed using a square shaped driven patch and two hexagonal slotted tunable parasitic elements placed in the H-plane. The mutual coupling between the driven and tunable parasitic elements is controlled by changing the capacitance of varactor diodes loaded in the hexagonal slot. The relative lead and lag of current due to change in the dimension of tunable parasitic patch causes phase distribution across the elements resulting in continuous scanning of the main beam. The performance of the antenna is measured in three operating modes namely Reflector-Director (RD), Director-Reflector (DR) and broadside. In RD and DR mode, the main beam is continuously scanned from 14.4 ° to 40 ° and −14.4 ° to −40 ° respectively. The main beam is directed to 0 ° in the broadside mode with a gain of 3.36 dBi. The antenna achieves overall bandwidth from 2.43 to 2.47 GHz in all the operating modes without any impedance matching network. The reflection and radiation performance of the fabricated antenna shows good agreement with the simulation results.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.02.014
      Issue No: Vol. 88 (2018)
  • A novel adaptive real-time detection algorithm for an area-efficient CMOS
           spike detector circuit
    • Authors: Shashank Dwivedi; Anup K. Gogoi
      Pages: 87 - 97
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 88
      Author(s): Shashank Dwivedi, Anup K. Gogoi
      For implantable neural detection and recording systems, computationally simple methods are preferred over complex algorithms for power efficiency. Amplitude threshold is the simplest and the most widely employed method for neural spike detection. However, this conventional method for setting the threshold is sensitive to the spike firing rate and spike amplitude. In this work, a novel approach is described for a real-time calculation of the detection threshold in a way that is robust to the change in spike firing rate as well as spike amplitude. An algorithm is proposed that adaptively sets the threshold from background activity by approximating the nonlinear energy operator (NEO). The detection method can distinguish neural spikes accurately with firing rate greater than 100 Hz. The spike detector circuit dissipates 5.1  μ W of power per channel and occupies 0.018 mm2 of layout area when implemented in 0.18  μ m CMOS process.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.02.023
      Issue No: Vol. 88 (2018)
  • Efficient GLRT/DOA spectrum sensing algorithm for single primary user
           detection in cognitive radio systems
    • Authors: Hager S. Fouda; Amr H. Hussein; Mahmoud A. Attia
      Pages: 98 - 109
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 88
      Author(s): Hager S. Fouda, Amr H. Hussein, Mahmoud A. Attia
      Spectrum sensing is a fundamental requirement for cognitive radio systems. In this paper, a new spectrum sensing technique with multiple antenna elements is proposed for further performance enhancement. The proposed technique is based on direction of arrival (DOA) knowledge and beamforming of the received signals. In this context, the Signal to Noise Ratio (SNR) will be significantly improved. The proposed technique is developed to detect only one primary user. Test statistics which determine the absence/presence of the Primary User (PU) are derived by using generalized likelihood ratio test (GLRT) approach. Two test statistics are developed with and without prior knowledge of noise power. Theoretical analysis for probability of detection, probability of false alarm, and their associated threshold are performed based on the statistical theory. Under a few samples scenario, simulations revealed that the proposed technique outperforms the other existing techniques particularly at low SNR regimes. In addition, it consumed less sensing time. Further, simulation results have confirmed theoretical analysis.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.012
      Issue No: Vol. 88 (2018)
  • Transition metal dichalcogenide MoS2 field-effect transistors for analog
           circuits: A simulation study
    • Authors: Baolin Wei; Chao Lu
      Pages: 110 - 119
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 88
      Author(s): Baolin Wei, Chao Lu
      As the scaling of silicon MOSFET approaches to its physical limit, research efforts have been made in exploring alternative devices. In this work, fundamental design metrics of analog circuits using two-dimensional transition metal dichalcogenide (2D-TMD) molybdenum disulfide (MoS2) transistors are systematically investigated and compared with the state-of-the-art silicon MOSFETs. Based on analytical derivation and numerical simulations, we find that the drain current efficiency and channel length modulation factor of MoS2 transistors are less relevant to the channel length. Under a condition of the same bias current and device geometry, intrinsic gains of MoS2 transistors are at least 12.3 dB higher than silicon MOSFETs. Three case studies are performed to investigate the use of MoS2 transistors in analog circuits. The key performance indicators of operational amplifiers, such as circuit area, power consumption, voltage gain, gain-bandwidth product (GBW), and tolerance to random process variation are studied. Simulation results demonstrate that MoS2 based analog circuits lead to significant improvement in performance and are more resilient to process variation. For example, when designing two-stage common source amplifiers, under an iso-GBW condition, MoS2-based design can increase voltage gain by at least 72%, save circuit area by 45–60%, and reduce power consumption by 11–58% than silicon-based designs.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.02.025
      Issue No: Vol. 88 (2018)
  • Design of stubs loaded SIR filters by reflection coefficient analysis
    • Authors: Xiuhan Liu; Weiwei Wu; Wentao Yuan; Ye Yuan; Naichang Yuan
      Pages: 120 - 125
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 88
      Author(s): Xiuhan Liu, Weiwei Wu, Wentao Yuan, Ye Yuan, Naichang Yuan
      In this paper, a new method for designing stubs loaded SIR filter is presented. We can calculate the reflection coefficient of stubs loaded resonator directly by converting the admittance to input terminal. This method replaces the transmission matrix and even-mode and odd-mode analysis. Then, genetic algorithm (GA) is applied to search the corresponding electrical parameters, which provides a more effective and intuitive way to design filters. Then, an ultra-wideband bandpass filter using short-stub loaded SIR is realized, which exhibits a good frequency selectivity from 3.1 GHz to 10.4 GHz. In addition, by applying this method, a dual-passband filter with short and open stubs is achieved. It contains two wide bands at 2 GHz and 5.8 GHz, which concerns the frequencies of GPS and WLAN. Meanwhile, the sizes of these filters are further minimized by bend structure. Finally, the filters are manufactured. As a result, the measured results are in good agreement with the calculated ones. These filters exhibit great frequency-selection characteristics: flat passbands and extremely sharp rejections around the passband. So, based on the verifications of the manufactured filters, this method can be widely used in microwave filter design field.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.001
      Issue No: Vol. 88 (2018)
  • A compact resistively-loaded dipole antenna fed by a triangular tapered
           transmission line for imaging applications
    • Authors: Doojin Lee
      Pages: 126 - 133
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 88
      Author(s): Doojin Lee
      This study proposes a compact resistively loaded dipole antenna (CRDA) for imaging applications. The triangular tapered transmission line has been introduced to feed the balanced structure of the CRDA and 78.5% of energy was successfully delivered to the end of the transmission line. The fabricated CRDA, which was fed by the triangular tapered transmission line, has been analyzed in terms of the characteristics of its reflected pulse and current distribution for image quality aspects by comparing it with a conventional dipole antenna (CDA). Using the CRDA, the imaging experiment for a perfect electric conductor (PEC) target and fabricated a multi-layered head phantom was performed. With this experiment, the target image has been successfully reconstructed by the delay and sum technique in the end.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.014
      Issue No: Vol. 88 (2018)
  • Impact of hardware impairments on large-scale MIMO systems over composite
           RG fading channels
    • Authors: Xingwang Li; Mengyan Huang; Xinji Tian; Hui Guo; Jin Jin; Changsen Zhang
      Pages: 134 - 140
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 88
      Author(s): Xingwang Li, Mengyan Huang, Xinji Tian, Hui Guo, Jin Jin, Changsen Zhang
      In this paper, we analyze the impact of receiver hardware impairments on the achievable sum rate of multiple-input multiple-output (MIMO) systems, where the channel follows composite Rician-Gamma (RG) distribution and may be correlated at the transmitters. More specifically, we derive the analytical expressions on the lower bound for the achievable sum rate of regular and large-scale MIMO systems with zero-forcing (ZF) receivers. In order to obtain deeper insights, the asymptotic analysis for the achievable sum rate of regular MIMO systems at high signal-to-noise ratio (SNR) regime is explored. It explicitly reveals that there is a finite rate ceiling on the achievable sum rate for regular MIMO systems at high SNRs, which is irrespective of the transmit power. Additionally, for large antenna configuration, three representative cases are considered insightfully by deriving in closed-form expressions for the asymptotic achievable sum rate. It demonstrates that the finite rate ceiling vanishes for large-scale MIMO limits, which means that large-scale MIMO systems are robust to hardware impairments.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.010
      Issue No: Vol. 88 (2018)
  • Efficient error detection in soft data fusion for cooperative spectrum
    • Authors: Dost Muhammad Saqib Bhatti; Saleem Ahmed; Nasir Saeed; Bushra Shaikh
      Pages: 141 - 147
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 88
      Author(s): Dost Muhammad Saqib Bhatti, Saleem Ahmed, Nasir Saeed, Bushra Shaikh
      The primary objective of cooperative spectrum sensing (CSS) is to determine whether a particular spectrum is occupied by a licensed user or not, so that unlicensed users called secondary users (SUs) can utilize that spectrum, if it is not occupied. For CSS, all SUs report their sensing information through reporting channel to the central base station called fusion center (FC). During transmission, some of the SUs are subjected to fading and shadowing, due to which the overall performance of CSS is degraded. We have proposed an algorithm which uses error detection technique on sensing measurement of all SUs. Each SU is required to re-transmit the sensing data to the FC, if error is detected on it. Our proposed algorithm combines the sensing measurement of limited number of SUs. Using Proposed algorithm, we have achieved the improved probability of detection (PD) and throughput. The simulation results compare the proposed algorithm with conventional scheme.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.02.011
      Issue No: Vol. 88 (2018)
  • Dual head static clustering algorithm for wireless sensor networks
    • Authors: Tripatjot Singh Panag; J.S. Dhillon
      Pages: 148 - 156
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 88
      Author(s): Tripatjot Singh Panag, J.S. Dhillon
      Clustering of nodes is often used in wireless sensor networks to achieve data aggregation and reduce the number of nodes transmitting the data to the sink. This paper proposes a novel dual head static clustering algorithm (DHSCA) to equalise energy consumption by the sensor nodes and increase the wireless sensor network lifetime. Nodes are divided into static clusters based on their location to avoid the overhead of cluster re-formation in dynamic clustering. Two nodes in each cluster, selected on the basis of the their residual energy and their distance from the sink and other nodes in the cluster, are designated as cluster heads, one for data aggregation and the other for data transmission. This reduces energy consumption during intra-cluster and inter-cluster communication. A multi-hop technique avoiding the hot-spot problem is used to transmit the data to the sink. Experiments to observe the energy consumption patterns of the nodes and the fraction of packets successfully delivered using the DHSCA suggest improvements in energy consumption equalisation, which, in turn, enhances the lifetime of the network. The algorithm is shown to outperform all the other static clustering algorithms, while being comparable with the performance of the best dynamic algorithm.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.03.019
      Issue No: Vol. 88 (2018)
  • A compact dual, triple band resonators for negative permittivity
    • Authors: Dushyant Marathe; Kishore Kulat
      Pages: 157 - 165
      Abstract: Publication date: May 2018
      Source:AEU - International Journal of Electronics and Communications, Volume 88
      Author(s): Dushyant Marathe, Kishore Kulat
      We report, two different dual and triple-band designs of single negative meta-atoms based on combination of individual Z-shaped and S-shaped inclusions. The multi-band responses for proposed resonators are obtained based on combination of individual resonant structures which exhibit electric resonances at different frequencies in microwave region. Numerical simulations and parameter extractions using retrieval method for normally incident wave demonstrate negative permittivity response over frequencies 3.27–4.5 GHz and 7.37–9 GHz for metamaterial made of dual-resonant meta-atom (DRMA). Further, metamaterial made of modified version i.e., triple-resonant meta-atom (TRMA) has negative values for permittivity over frequencies 2.79–3.5 GHz, 6.4–7.5 GHz and 8.93–11.0 GHz. The magnitude of reflection and transmission coefficient obtained from numerical simulations are further validated with microwave free space measurements. The equivalent circuit model developed for TRMA is validated with numerically simulated results. The effective medium ratio ( λ 0 / p ) for proposed resonators is compared with various other metamaterial resonators to indicate compact nature. The proposed DRMA/TRMA resonators can find applications in performance improvement of multiband devices such as antennas, antenna arrays, filters and in realization of microwave sensors, detectors at microwave frequency regime.

      PubDate: 2018-04-15T08:55:29Z
      DOI: 10.1016/j.aeue.2018.02.026
      Issue No: Vol. 88 (2018)
School of Mathematical and Computer Sciences
Heriot-Watt University
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