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COMPUTER SCIENCE (1228 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 872 Journals sorted alphabetically
3D Printing and Additive Manufacturing     Full-text available via subscription   (Followers: 23)
Abakós     Open Access   (Followers: 4)
ACM Computing Surveys     Hybrid Journal   (Followers: 29)
ACM Journal on Computing and Cultural Heritage     Hybrid Journal   (Followers: 8)
ACM Journal on Emerging Technologies in Computing Systems     Hybrid Journal   (Followers: 16)
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: 9)
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: 18)
ACM Transactions on Computer-Human Interaction     Hybrid Journal   (Followers: 15)
ACM Transactions on Computing Education (TOCE)     Hybrid Journal   (Followers: 6)
ACM Transactions on Design Automation of Electronic Systems (TODAES)     Hybrid Journal   (Followers: 6)
ACM Transactions on Economics and Computation     Hybrid Journal   (Followers: 1)
ACM Transactions on Embedded Computing Systems (TECS)     Hybrid Journal   (Followers: 3)
ACM Transactions on Information Systems (TOIS)     Hybrid Journal   (Followers: 20)
ACM Transactions on Intelligent Systems and Technology (TIST)     Hybrid Journal   (Followers: 8)
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: 8)
ACM Transactions on Speech and Language Processing (TSLP)     Hybrid Journal   (Followers: 9)
ACM Transactions on Storage     Hybrid Journal  
ACS Applied Materials & Interfaces     Hybrid Journal   (Followers: 32)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 2)
Acta Informatica Malaysia     Open Access  
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Ad Hoc Networks     Hybrid Journal   (Followers: 11)
Adaptive Behavior     Hybrid Journal   (Followers: 10)
Advanced Engineering Materials     Hybrid Journal   (Followers: 28)
Advanced Science Letters     Full-text available via subscription   (Followers: 11)
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: 4)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 19)
Advances in Computer Engineering     Open Access   (Followers: 4)
Advances in Computer Science : an International Journal     Open Access   (Followers: 14)
Advances in Computing     Open Access   (Followers: 2)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 56)
Advances in Engineering Software     Hybrid Journal   (Followers: 28)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 14)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 22)
Advances in Human-Computer Interaction     Open Access   (Followers: 20)
Advances in Materials Science     Open Access   (Followers: 14)
Advances in Operations Research     Open Access   (Followers: 12)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Remote Sensing     Open Access   (Followers: 50)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Advances in Technology Innovation     Open Access   (Followers: 6)
AEU - International Journal of Electronics and Communications     Hybrid Journal   (Followers: 8)
African Journal of Information and Communication     Open Access   (Followers: 9)
African Journal of Mathematics and Computer Science Research     Open Access   (Followers: 4)
AI EDAM     Hybrid Journal   (Followers: 1)
Air, Soil & Water Research     Open Access   (Followers: 12)
AIS Transactions on Human-Computer Interaction     Open Access   (Followers: 6)
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: 6)
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: 12)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 13)
Annals of Pure and Applied Logic     Open Access   (Followers: 3)
Annals of Software Engineering     Hybrid Journal   (Followers: 13)
Annals of West University of Timisoara - Mathematics and Computer Science     Open Access  
Annual Reviews in Control     Hybrid Journal   (Followers: 8)
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: 3)
Applied Clinical Informatics     Hybrid Journal   (Followers: 2)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 13)
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: 6)
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: 147)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5)
arq: Architectural Research Quarterly     Hybrid Journal   (Followers: 8)
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 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: 5)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Automatica     Hybrid Journal   (Followers: 13)
Automation in Construction     Hybrid Journal   (Followers: 7)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Basin Research     Hybrid Journal   (Followers: 5)
Behaviour & Information Technology     Hybrid Journal   (Followers: 51)
Big Data and Cognitive Computing     Open Access   (Followers: 3)
Biodiversity Information Science and Standards     Open Access  
Bioinformatics     Hybrid Journal   (Followers: 315)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 20)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 35)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 49)
British Journal of Educational Technology     Hybrid Journal   (Followers: 151)
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   (Followers: 2)
Canadian Journal of Electrical and Computer Engineering     Full-text available via subscription   (Followers: 15)
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: 15)
ChemSusChem     Hybrid Journal   (Followers: 7)
China Communications     Full-text available via subscription   (Followers: 8)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
CIN Computers Informatics Nursing     Hybrid Journal   (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)
Clinical eHealth     Open Access  
Cluster Computing     Hybrid Journal   (Followers: 2)
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: 13)
Communication Theory     Hybrid Journal   (Followers: 23)
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 Information Science and Management Engineering     Open Access   (Followers: 4)
Communications in Partial Differential Equations     Hybrid Journal   (Followers: 3)
Communications of the ACM     Full-text available via subscription   (Followers: 51)
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   (Followers: 1)
Computational and Applied Mathematics     Hybrid Journal   (Followers: 3)
Computational and Mathematical Biophysics     Open Access   (Followers: 1)
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: 12)
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: 17)
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: 8)
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: 31)
Computer     Full-text available via subscription   (Followers: 103)
Computer Aided Surgery     Open Access   (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)

        1 2 3 4 5 6 7 | Last

Journal Cover
AEU - International Journal of Electronics and Communications
Journal Prestige (SJR): 0.42
Citation Impact (citeScore): 2
Number of Followers: 8  
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1434-8411
Published by Elsevier Homepage  [3155 journals]
  • Fully differential implementation of a Delta-Sigma Modulator based on the
           Pseudo-Pseudo Differential Technique
    • Abstract: Publication date: Available online 11 December 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Elena Cabrera-Bernal, Fernando Muñoz, Antonio Torralba, Clara Luján-Martínez Flicker noise and distortion are the main limitations in biomedical applications, especially for Switched Capacitor implementations, where the flicker noise is folded into the signal band. To remove the flicker noise and increase the linearity, the Pseudo-Pseudo Differential (P2D) technique has been proposed, where a single-ended signal is processed in a differential way. This paper presents the first silicon implementation of a second order Comparator-Based Switched-Capacitor (CBSC) delta-sigma modulator based on a variation of the P2D technique. Experimental results in a standard 180 nm CMOS technology show an improvement of 10 dB in the Peak SNDR, 5 dB in the DR, and 9 dB in the SFDR over its pseudo differential counterpart, which is the preferred differential implementation for CBSC circuits. Moreover, it is achieved with a reduction in the power consumption.
  • Compact Wideband MIMO Antenna for 4G WI-MAX, WLAN and UWB Applications
    • Abstract: Publication date: Available online 10 December 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Pratima.C. Nirmal, Anil Nandgaonkar, Sanjay Nalbalwar, Rajiv K. Gupta This article proposes a compact wideband MIMO antenna. The antenna comprises of two identical modified P shaped monopole radiators, spatially oriented at 180o to each other with side to side spacing of 0.075λo, where λo is the wavelength corresponding to the lowest operating frequency. To design a compact antenna, a semicircular monopole with a rectangular strip is designed instead of a circular monopole. This P shaped monopole antenna offers same impedance bandwidth with 50% size reduction. To enhance the impedance bandwidth of the antenna, the effective current path length is increased by introducing two semi-circular slots in P shaped monopole antenna. To achieve the desired impedance bandwidth of 2.5- 12 GHz, the rectangular strip is corrugated on both sides in the slotted P shaped monopole. Triangular slots and meshed metal strip are introduced in the ground plane to achieve high mutual coupling over wideband. The triangular slots act as variable length capacitance and exhibits wide band notch characteristics. A meshed metal strip acts as decoupling structure for the surface current emerging from the surface waves and also act as reflector for space waves. Those bands which are not rejected by triangular slots, are notched by meshed metal strips. Thus by employing both triangular slots and meshed metal strip, isolation> 20 dB is achieved over 2.5- 12 GHz. The proposed antenna is a novel design which has smaller dimensions and still offers isolation> 20 dB over a wider impedance bandwidth of 2.5 GHz to 12 GHz as compared to state of art antenna structures reported in literature. The band stop characteristics of proposed isolation techniques are analyzed by suspended stripline method. Mutual coupling reduction is also analyzed with the help of vector surface current density and magnetic field distribution. The proposed structure has compact dimensions of 0.25 λ0 × 0.241 λ0. The fabricated prototype antenna exhibits envelope correlation coefficient (ECC) < 0.02, diversity gain> 9.5 dB and stable radiation patterns. The antenna is suitable for 4G WI-MAX, WLAN and UWB applications.
  • Simulation Study of Hetero Dielectric Tri Material Gate Tunnel FET based
           Common Source Amplifier Circuit
    • Abstract: Publication date: Available online 8 December 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Umesh Dutta, M.K Soni, Manisha Pattanaik Tunneling Field Effect Transistor (TFET) has emerged as an alternative device to MOSFET for designing low power analog and digital integrated circuits. This paper investigates the performance of a common source amplifier circuit designed using Gate-All-Around Hetero Dielectric Tri Material Gate TFET device. HD-TMGTFET device is designed on Visual TCAD tool and a look up table-based Verilog A model has been designed to perform SPICE circuit simulations. The performance of the HD-TMGTFET based CS amplifier circuit is compared with the MOSFET based amplifier designed using 65 nm MOSFET device. Device simulation results show that HD-TMGTFET device exhibits steep subthreshold slope of 21.2 mV/decade, high ON current of 7.5x10-6A/µm and extremely low OFF state current of the order of 10-19A/µm. The device also exhibits extremely low values of miller capacitances and has maximum unity gain frequency of 124 GHz at gate voltage of 0.9 V. HD-TMGTFET device based amplifier can provide amplification of up to 3 times within the frequency range of 100 KHz to 0.1 GHz and on the other hand MOSFET based amplifier circuit provides amplification up to 1.58 times over limited frequency range of 1 MHz, clearly showing the potential of using HD-TMGTFET device in high frequency applications.
  • Dissimulation-based and load-balance-aware routing protocol for request
           and event oriented mobile wireless sensor networks
    • Abstract: Publication date: Available online 8 December 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Bournane Abbache, Sofiane Aissani, Mawloud Omar, Farah-Sarah Ouada, Nawel Yessad, Mohamed Azni, Abdelkamel Tari Mobile Wireless Sensor Network (MWSN) is a set of interconnected mobile sensor devices forming a dynamic network without a fixed administration. MWSN is used in various domains, such as disaster detection, medical systems, military applications, vehicular communications, and in other sensitive applications. Compared to the classical sensor networks, MWSNs involve an additional constraint consisting of the topology change frequency caused by the mobility of sensor devices. This influences highly the energy consumption and consequently the network reliability. In this paper, we take in charge this important issue and we contribute by the proposition of an efficient and energy-aware routing protocol. The proposed protocol operates for both request and event oriented MWSN applications. It introduces the sensor device mobility history in order to build-up stable routing paths, and incorporates a novel technique of dissimulation in order to exchange the mobility control messages without overhead. We have evaluated the performances of the proposed protocol through simulations, in which it provides effective results in terms of energy consumption and load-balancing.
  • A CT ΔΣ Modulator Using 4-Bit Asynchronous SAR Quantizer and
           MPDWA DEM
    • Abstract: Publication date: Available online 5 December 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Sahel Javahernia, Esmaeil Najafi Aghdam, Pooya Torkzadeh The current paper aims at presenting a low-power second-order input-feedforward continuous-time (CT) ΔΣ modulator for audio applications. It uses a 4-bit asynchronous successive approximation register (SAR) quantizer which is more power efficient than the usual flash converter. Furthermore, in order for the proposed modulator to reduce the noise stemming from the component mismatches of the feedback digital-to-analog converter (DAC), it applies a modified partitioned data weighted averaging (MPDWA) dynamic element matching (DEM) so as to solve the DWA DEM-in band-tone problem. Despite the implementation of MPDWA, no further delay caused in the ΔΣ feedback loop compared to the conventional DWA. The implementation of the above-mentioned DEM in the modulator and required reforms have led to a new design with better performance and favorable figure of merit (FOM) value. The designed modulator which is simulated using 0.18µm CMOS technology, achieves 84.17 dB SNDR for 20 KHz signal bandwidth and dissipates 54 µw while its FOM is obtained about 143 fJ/conv.-step.
  • Approximation of Peak-to-Average Power Ratio of Generalized Frequency
           Division Multiplexing
    • Abstract: Publication date: Available online 4 December 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Sudhir Kumar Mishra, Kishore Damodar Kulat Generalized frequency division multiplexing (GFDM) is a generalized form of the multi-carrier system with a flexibility to vary the number of subcarriers, the number of time slots and the associated pulse shaping filter for achieving desired performance. Peak to average power ratio (PAPR) is a crucial parameter to be considered while designing systems for low power consumption devices. It has been found in the literature that the PAPR of a GFDM system is higher as compared to the versatile orthogonal frequency division multiplexing (OFDM) systems for the same number of subcarriers.This paper presents a simple intuitive methodology based on order-statistics to derive an expression for the PAPR of a GFDM system. The expression of the PAPR for a simple square root companded GFDM system is also derived based on the same principle. The derived PAPR expressions for both these cases are validated through extensive Monte-Carlo simulations. The derived expressions can be useful to the research community to evaluate the PAPR of GFDM system for a given number of subcarriers K, the number of time slots M, and the considered pulse shaping filter. The PAPR results also conform to the simulation results presented by other researchers in the literature.
  • A new dual band 4 x 4 butler matrix with dual band 3dB quadrature branch
           line coupler and dual band 45° phase shifter
    • Abstract: Publication date: Available online 30 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Aijaz M. Zaidi, Syed A. Imam, Binod K. Kanaujia, Karumudi Rambabu, Kunal Srivastava, Mirza Tariq Beg A new dual band 4 × 4 butler matrix (BM) without crossover has been proposed, implemented and analyzed in this paper. A new dual band 45° phase shifter has also been proposed. The dual band BM, dual band 3dB quadrature branch line coupler (BLC) and dual band 45o phase shifter have been designed using Keysight Technologies’ Advanced Design System (ADS) software and implemented on the Rogers 2.33, having a thickness of 0.787 mm for 1.0 GHz and 2.5 GHz operating frequencies. Before the implementation of the proposed BM, the dual band 3dB quadrature BLC and dual band 45° phase shifter have been designed, implemented and analyzed. The proposed dual band 4 × 4 BM has been developed by placing four dual band 3dB quadrature BLCs and two dual band 45° phase shifters at their appropriate positions. Circuit parameters variation of the proposed BLC, phase shifter and BM with frequency ratios have been studied in this paper. The measured and simulated results of the dual band BM validated the design methodology. A performance analysis comparing the proposed BM with the existing butler matrices has also been carried out.
  • 2D anAlytical moDeling and SIMULATION of DUal material DG MOSFET for
           BIOSENSing application
    • Abstract: Publication date: Available online 30 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Buvaneswari Balakrishnan, Neerathilingam Balasubramanian Balamurugan In the recent times, the performance of MOSFET in the nanoscaled region attains improvisations through several alternative device structures. Amongst many advanced MOSFET structures, the Double Gate (DG) MOSFET is one such structure which mitigates short channel effects because of its excellent scalability. Among the various structures, FET- based biosensors have shown an accelerated growth recently. Even though many analytical models are available for the Dual Material DG (DMDG) MOSFET structures, this work endeavours to introduce an analytical modeling of nanocavity embedded DMDG structure for the first time. The expression for surface potential is obtained by solving the 2-D Poisson’s equation using a parabolic-potential approach. The threshold voltage is determined from the minimum surface potential model. Sensitivity is computed in terms of relative change in the threshold voltage and it is derived using the model. The influence of various device geometrical parameters like length and thickness of the nanocavity on the sensitivity has been investigated. Further, a comparison of the sensitivity of DG MOSFET and DMDG MOSFET has also been made and the derived results are validated against TCAD simulation results.
  • On Development of a MIMO Antenna for Coupling Reduction and WiMAX
           Suppression Purposes
    • Abstract: Publication date: Available online 28 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): B. Azarm, J. Nourinia, Ch.Ghobadi, Maryam Majidzadeh, N. Hatami A multiple-input multiple-output (MIMO) WiMAX band-notched antenna with reduced mutual coupling is proposed for ultra-wideband (UWB) applications. The proposed MIMO structure consists of two square monopole antennas with two modified L-shaped slots, a rectangular ground plane structure, and a rectangular parasitic structure for increased isolation. Simulation and measurement studies are used to probe the antenna performance in terms of s-parameters, isolation between the two input ports (S21), antenna gain, group delay, ECC, 2D and 3D radiation pattern. Results show a bandwidth with S11 , S22 ≤ -10 dB, S21 ≤ -20 dB, and frequency ranged from 2.8 to 10.9 GHz excluding a rejected band from 3.4 to 3.9 GHz, focusing on WiMAX frequency band. The MIMO antenna prototype with a compact size of 18×36 mm2 is fabricated and measured. Based on the obtained experimental results, the proposed MIMO antenna could be regarded as a good candidate for UWB MIMO antenna with band-notch characteristics.
  • fRobust Cyclic Beamforming against Cycle Frequency Error in Gaussian and
           Impulsive Noise Environments
    • Abstract: Publication date: Available online 26 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Fangxiao Jin, Tianshuang Qiu, Tao Liu A robust cyclic array beamforming method is proposed for cyclostationary signals to counter against the cycle frequency error (CFE) in Gaussian and impulsive noise environments. In this approach, the maximum correntropy criterion (MCC) is employed as the cost function to compute an appropriate weight vector for performing cyclic adaptive array beamforming. We show that a closed form solution of weighting vector yields a weighted least-square-like formulation by using the MCC. The corresponding performances of unbiasedness and consistency are evaluated. Further, in order to solve the performance degradation caused by the CFE, an optimization method is developed based on the fact that the correntropy-based correlation (CRCO) function of the output signals will approach its maxima without any CFE. Finally, a robust iterative algorithm without the prior knowledge of the direction vector of the signal of interest (SOI) is proposed for robust adaptive array beamforming.
  • CFOA based Low pass and High Pass Fractional Step Filter Realizations
    • Abstract: Publication date: Available online 26 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Rakesh Verma, Neeta Pandey, Rajeshwari Pandey This contribution puts forward a new proposal for Current Feedback Operational Amplifier (CFOA) based Low pass (LP) and High Pass (HP) Fractional Step Filters (FSFs). The proposed filters are designed by approximating the fractional Laplacian operator by an appropriate integer order transfer function. Subsequently, functional block diagram (FBD) approach is used for CFOA based realization of LP and HP FSFs of order (1+α). Higher order FSFs are realized by cascading FSF of order (1+α) with higher integer order filters. To illustrate this, CFOA based LP (HP) FSFs of order (5+α) are obtained by cascading LP (HP) FSFs of order (1+α) with proposed leapfrog realization of 4th order LP (HP) filter. The proposal is verified through SPICE simulations and experimentation. Stability, sensitivity and non-ideal analyses are also included.
  • New Dual Material Double Gate Junctionless Tunnel FET: Subthreshold
           Modeling and Simulation
    • Abstract: Publication date: Available online 22 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): G. Lakshmi Priya, N.B. Balamurugan A subthreshold analytical model for Dual Material Double Gate Junctionless Tunnel FET (DMDG JLTFET) is developed. To analyze the behavior of short channel device, relevant parameters such as surface potential, electric field, threshold voltage, drain current, transconductance-to-drain current ratio, subthreshold slope and subthreshold swing are extracted from the 2-D analytical solution of Poisson's equation. Relating DMDG JLTFET to Junctionless MOSFETs, the results show significant reduction of Short Channel Effects (SCEs) at the drain end. The analytical model for DMDG JLTFET is effective due to the combined supremacy of uniform doping in the channel, usage of high-K gate dielectric material and work function engineering in the gate metal. The results obtained from the analytical model are simulated and validated using 2-D Sentaurus TCAD device simulator.
  • Design and Analysis of Seven-Bands-Slot-Antenna with Small Frequency Ratio
           for different Wireless Applications
    • Abstract: Publication date: Available online 22 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Praveen Chaurasia, Binod Kumar Kanaujia, Santanu Dwari, Mukesh Kumar Khandelwal In this paper, a low profile planar multiband slot antenna covering numerous wireless applications is presented. The proposed antenna resonates for seven frequency bands corresponding to centre frequencies 2.54 GHz, 3.48 GHz, 4.02 GHz, 4.34 GHz, 5.1 GHz, 5.54 GHz and 6.24 GHz. The antenna also shows circular polarization in the two frequency bands ranging from 3.42 to 3.68 GHz and 6.2 to 6.94 GHz. A very small frequency ratio of 1.37007, 1.15517, 1.0796, 1.17511, 1.0862 and 1.1263 is realized between the two consecutive bands. The designing of the proposed antenna is carried out by means of Ansys HFSS and simulated results are found in good agreement with the measured results.
  • Realization of ASK/BPSK Modulators and Precision Full-Wave Rectifier Using
    • Abstract: Publication date: Available online 20 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Atul Kumar, Bhartendu Chaturvedi This paper introduces two new circuits which are capable of realizing digital modulation schemes namely, amplitude shift keying (ASK) and binary phase shift keying (BPSK). First circuit named as ASK/BPSK modulator-1 employs one dual-X second generation current conveyor (DXCCII), three MOS switches and three resistors. On the other hand, second circuit named as ASK/BPSK modulator-2 comprises one DXCCII, three MOS switches and one grounded resistor. Both ASK and BPSK schemes are simultaneously realizable with both proposed circuits. In communication systems, both ASK and BPSK schemes are commonly used. Furthermore, a little modification in ASK/BPSK modulator-1 enables the realization of full-wave precision rectifier. The circuit of rectifier comprises one DXCCII, two resistors and two MOS switches. The non-ideal considerations of proposed circuits including non-ideal transfer gains as well as parasitic of DXCCII are also explored. HSPICE simulation results using IBM CMOS technology of 0.13 µm are given to validate proposed circuits.
  • Communication Technologies and Security Challenges for Internet of Things:
           A Comprehensive Review
    • Abstract: Publication date: Available online 20 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Prachin Bhoyar, Parul Sahare, S.B. Dhok, R.B. Deshmukh ’Internet of things’ (IoT) realize a network of millions of connected devices like sensors, actuators and transceivers. Being a composite system, IoT must deal with the associated problems while meeting throughput, latency, energy consumption, and security criteria. In this work, wireless technologies have been classified based on the mechanisms of physical layer, media access control layer, and network layer. The fundamentals of wireless communication and all the non-trivial interests associated with these three layers are summarized with respect to the criteria imposed by IoT. Various security threats at these layers and vulnerabilities of the standards against such attacks have also been listed out. To mitigate these problems, instead of relying on any one particular solution, more emphasis is given on the integrated approach where layer-wise solutions are provided. Thereafter, a brief analysis of the available wireless communication standards and their salient features are discussed. Research scope and challenges in IoT applications ranging from low power, low data rate, short range to extended coverage are identified, followed by possible directions to be taken. Additionally, the third generation partnership project for low-power wide area solutions to meet the IoT requirements are analyzed in detail.
  • New Approximate Expressions of Average Symbol Error Probability,
           Probability of Detection and AUC with MRC over Generic and Composite
           Fading Channels
    • Abstract: Publication date: Available online 20 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Puspraj Singh Chauhan, Sandeep Kumar, Sanjay Kumar Soni The present work covers the wide range of distributions and proposes the moment generating function (MGF) based analytical framework to derive the average symbol error probability (SEP), the average probability of detection (PD), and the average area under the receiver operating characteristic curve (AUC) for the wireless system with maximal ratio combining (MRC) diversity. The proposed solutions are expressed in terms of Fox’s H and bivariate Fox’s H-functions which are widely being used in the current literature. Finally, the analytical framework, thus proposed has been used in applications, such as ultra-wideband (UWB) single-input-single-output (SISO) and multiple-input-multiple-output (MIMO) system and the impact of the number of transmitting and receiving antennas for MIMO system over the average SEP has been analysed. The correctness of the proposed solutions has been corroborated by comparing them with Monte-Carlo simulation.
  • Efficient DOA Estimation based on Difference-set Table Traversal Searching
           for the Generalized Coprime Array
    • Abstract: Publication date: Available online 20 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Xiang-Dong Huang, Jing-Wen Xu, Tian-Lei Nian, Qian Lin This paper aims to achieve both high degree-of-freedom (DOF) and high efficiency in direction-of-arrival (DOA) estimation. On one hand, to realize high DOF, this paper optimizes the interelement spacings and the displacement of the generalized coprime sparse array. On the other hand, to achieve high efficiency, a series of approaches are proposed: Firstly, a normalized-coordinate representation is formulated to explore the conversion relationship between the covariance matrix of the physical sparse array and that of the expected virtual Nyquist uniform linear array (ULA); Secondly, a difference-set table traversal searching method is proposed to guide this conversion; Thirdly, the mapping relationship between the element coordinates in the observation covariance matrix and a lag of the Nyquist-ULA is built up, from which the DOAs can be readily estimated through MUSIC decomposition. Deep analysis shows that the proposed estimator saves approximately O((MN+1)3) times of multiplications involved in the spatial smoothing based estimator. Numerical results also confirms that our proposed estimator does not pay the cost of performance attenuation, which presents vast potentials in radar, communication and sonar systems etc.
  • A Wearable Piezoresistive Microaccelerometer with Low Cross-axis
           Sensitivity for Neurological Disease Diagnosis
    • Abstract: Publication date: Available online 20 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Sonali Biswas, Anup Kumar Gogoi Inertial MEMS sensors having high performance play a key role in several biomotion applications. However, in addition to high performance, there is a demand for wearable sensors in medical diagnostic purposes to be of small size and light weight. Tremor(2Hz-18Hz) and Seizure(0.5Hz-29Hz) occurs in patients suffering from several neurological disorders having acceleration value from almost 0g signifying fall to maximum ±6g signifying jerks. In order to capture such low g signals, reduced cross axis sensitivity is required, which is still a challenge in the available ones. This paper presents the design and analysis of such a wearable microaccelerometer of piezoresistive type for the diagnosis of neurological disorders having an area of about 25mm2and mass of around 6 mg. The sensitivity obtained for a dynamic range of ±6g is 0.33 mV/V/g, noise floor is 7.65 μg/Hz and cross axis sensitivity is 0.48%.
  • Inverted-A based UWB MIMO Antenna with Triple-band Notch and Improved
           Isolation for WBAN Applications
    • Abstract: Publication date: Available online 17 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Irene Suriya, Rajesh Anbazhagan A compact ultra wideband multiple–input multiple-output (UWB-MIMO) antenna with inverted-A monopole and band notch characteristics of LTE-A 43 band (3.8 GHz), C-band (3.9 – 4.2 GHz) and the IEEE 802.11ac band (5.1 – 5.85 GHz) with microstrip line feeding is proposed. The suppression of the inevitable mutual coupling for improved isolation is achieved by using a combination of techniques like orthogonal polarization, defected ground structure (DGS). The antenna has wideband impedance matching with S11 < -10 dB in the UWB frequency range from 3.1 to 10.6 GHz and has a low mutual coupling with S21 < -17 dB which can be inferred from the simulated and measured results. The antenna has a fractional bandwidth of 109.48 %, envelope correlation coefficient of 0.035 and capacity loss of 0.358, which proves the diversity characteristics of proposed MIMO antenna.
  • A Compact Low-Side Lobes Three-Layer Array Antenna for X-Band Applications
    • Abstract: Publication date: Available online 17 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Hossain Mardani, Javad Nourinia, Changiz Ghobadi, Maryam Majidzadeh, Bahman Mohammadi This paper proposes a low-side lobe lightweight array antenna for X-band applications with center frequency of 9.5 GHz. The proposed array antenna, being composed of 144 (12×12) single antenna elements, is designed in a three-layer configuration with total size of the 30cm×30cm. Technically speaking, it is composed of two substrates and three conductive layers on the top, bottom, and between the substrate layers. The main part of the feeding network is located on the bottom side of the antenna structure while the radiating patches are printed on the top side. The ground plane is placed in the middle layer between the two substrates. Isolation of the feed network from the radiating patches, which is realized by the embedded ground plane, yields cross-polarization and side lobe levels (SLLs) reduction. Besides, the feeding system excites the top side patches by connecting to them through vias. Moreover, 1 to 6 power dividers in the feeding system are connected to each other to form the complete 144-element array configuration. Adopting this technique provides easy development of a planar 2n×2n element array antenna. To achieve low side lobes, the Dolph-Chebyshev amplitude taper coefficients are used in the design process.
  • A new microstrip coupling system for realization of a differential
           dual-band bandpass filter
    • Abstract: Publication date: Available online 17 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Gholamreza Karimi, Mohsen Amirian, Ali Lalbakhsh, Mahnaz Ranjbar In this paper, a new Differential Dual-Band Wide-Bandpass Filter (DDWBF) using a new coupling system is presented. The adjustable coupling system composed of Two Coupled U-Shaped Structures (TCUSs) which create and control two initial passbands. Four TCUSs are then placed in four ports and connected through a defected fractal-based low impedance transmission line. Third order of Sierpinski fractal is applied on the transmission line to improve the out of band rejection of the differential mode along with common mode suppression. An analytical analysis is also presented to calculate the transmission zeros and poles of the DDWBF which verifies the authenticity of the design procedure. A prototype of the filter has been fabricated and tested which shows a very good agreement with the predicted results. According to the measured results, two wide passbands with fractional bandwidths of 45% and 13.5% at central frequencies of 4.32 and 8.61 GHz, respectively, have been achieved. The differential mode return loss is higher than 15 dB in both bands and the common mode suppression level is better than 14.85 dB. ‘
  • Minkowski, Giuseppe Peano and Koch Curves based Design of Compact Hybrid
           Fractal Antenna for Biomedical Applications using ANN and PSO
    • Abstract: Publication date: Available online 17 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Manpreet Kaur, Jagtar Singh Sivia In this work, an Artificial Neural Network (ANN) and Particle Swarm Optimization (PSO) techniques are used to compute the feed position of projected Minkowski, Giuseppe Peano and Koch curves based hybrid fractal Antenna (MGKA).The structure of projected MGKA is obtained by the combination of three different fractal geometries i.e. Minkowski, Giuseppe Peano and Koch. Different fractal geometries are combined to enhance the performance characteristics and to achieve better miniaturization. The projected MGKA consists of 1.6mm thick, low cost FR4 substrate whose relative permittivity is 4.4 and loss tangent value is 0.02. A set of 70 MGKAs with different dimensions is designed to obtain a data dictionary for the implementation of ANN and PSO techniques. The prototype is fabricated and then tested with Vector Network Analyzer (VNA). From the measured results, it is depicted that the resonant frequencies are 2.44 GHz and 5.84 GHz along with S (1, 1) values -18.23 dB and -12.71 dB. The fabricated prototype also provides excellent gains of 4.69 dB and 15.11 dB and operates within the Industrial, Scientific and Medical (ISM) frequency bands i.e. (2.4-2.5 GHz) and (5.82-5.85 GHz). The results of proposed ANN model and PSO techniques are well matched with the simulated and experimental values.
  • Printed Millimeter-Wave MIMO-Based Slot Antenna Arrays for 5G Networks
    • Abstract: Publication date: Available online 15 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Ayman Ayd R. Saad, Hesham A. Mohamed In this work, a broadband millimeter-wave (mm-wave) multiple-input–multiple-output (MIMO) antenna system for upcoming fifth generation (5G) networks is presented. The MIMO antenna system is two ports and realized using two antenna arrays, aligned in opposite directions. Each array consist of three elements in each, as each element is a simple recognized printed wide-slot antenna proximity excited by microstrip line with a widened tuning stub; manipulated for operating in the Ka-band, which includes the 28 and 38 GHz bands, as potential candidates for 5G communications. An electromagnetic band-gap (EBG) reflector is placed behind the antenna structure toward the feeding network to decrease backward radiation and improve the front-to-back (F/B) ratio. Results show that the proposed MIMO antenna system with EBG reflector provides wideband impedance bandwidth>27 GHz (from 22.5 to>50 GHz) and good radiation characteristics with a total realized gain up to 11.5 and 10.9 dBi at the two frequencies of interest, respectively. The envelope correlation coefficient (ECC) and diversity gain (DG) were evaluated and showed good MIMO performance. These remarkable features with the benefits of design simplicity and easily expansion to large-scale antenna system make the proposed design suitable for mm-wave communications.
  • A New 2 D Mathematical Modeling of Surrounding Gate Triple Material Tunnel
           FET using halo Engineering for Enhanced Drain Current
    • Abstract: Publication date: Available online 15 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): P. Vanitha, T.S. Arun Samuel, D. Nirmal In this paper, an analytical model is developed for new modified Surrounding Gate Triple Material Tunnel FET with halo doping engineering. The benefits of halo engineering and triple material surrounding gate SG-TFET are incorporated into a novel structure called Surrounding Gate Triple Material Tunnel FET with halo doping (H-SGTMTFET) has been proposed. A two dimensional analytical model is created by comprehending the Poisson’s equation utilizing parabolic approximation method with appropriate device boundary conditions. The various electrical parameters such as potential, electric field along the channel, vertical direction electric field and drain current of the H-SGTMTFET are derived and analyzed. The performance analysis is done for various gate material work functions and different halo lengths namely 10nm, 15nm and 20nm. It has been found that H-SGTMTFET structure gives very low leakage current IOFF (10-13A/µm), remarkable improvement in ON current (10-4A/µm) and the ION/IOFF ratio is 109. Also the ON current (ION) improves by 3 orders of magnitude compared with the Surrounding gate TFET. This new device undoubtedly, proves to be the best alternate for next generation low power and high speed applications. The analytical model has been compared with the simulator TCAD and an excellent conformity is achieved.
  • Adaptive Pilot Reuse Scheme for Nonzero Neighborhood Structured Downlink
           Channel in Massive MIMO
    • Abstract: Publication date: Available online 15 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Sanaz Rezvani Kenarsari, Mahmoud Ferdosizade Naeiny This study investigates the pilot contamination (PC) effect as the main bottleneck of time division duplex (TDD) massive multi-input multi-output (MIMO) systems. Based on sparsity properties of the angular representation of channel, a compressed sensing (CS)-based algorithm is proposed to estimate the channel response. It is demonstrated that the proposed channel estimation method can efficiently eliminate PC under certain conditions. To provide the PC elimination conditions, an adaptive pilot assignment (PA) scheme is designed based on non-zero neighborhood (NZN) structure of channel in beam domain. Despite of previous PA schemes, where a pilot sequence is surly reused by users of different cells, the proposed method assigns the same pilot sequence to the users with non-overlapped NZN, despite of being at the same cell or not. In the proposed PA method, the required length of pilot is adaptively obtained based on the PC severity in the system. Simulation results illustrate that compared to previous PA algorithms, the proposed scheme achieves better performance in terms of sum rate and the average pilot length.
  • Transparent cross-polarization converter with anomalous refraction
    • Abstract: Publication date: Available online 14 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Hongyu Shi, Jianxing Li, Shitao Zhu, Anxue Zhang, Zhuo Xu This paper proposed a cross-polarization converter, which can fully control the transmission phase and then manipulate the direction of refracted wave. A multi layered unit cell was designed and the transmission phase is continuously controlled by a single geometric parameter, which brings great convenient for simultaneously manipulating the polarization and propagation direction of the transmitted wave. The cross-polarized transmittance of the proposed polarization converter is higher than 0.9. In addition, the transmitted wave has an extremely low co-polarized component. Thus, the polarization conversion ratio is nearly 100%. Anomalous refraction was also realized by configuring a designed transmission phase distribution on the aperture of the cross-polarization converter. The proposed device was demonstrated by both simulation and measurement.
  • GO Aperture and Radiated Fields of Classical Omnidirectional
           Axis-Displaced Dual-Reflector Antennas
    • Abstract: Publication date: Available online 13 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Rafaela Neves de Barros Carvalho, Tcharles Vinícius Bernardes de Faria, Fernando José da Silva Moreira, Cássio Gonçalves do Rego This work presents the vector geometrical optics (GO) aperture field of classical omnidirectional dual-reflector antennas with an arbitrary main-beam direction in the elevation plane. These antennas are composed of two axially symmetric reflectors generated by axis-displaced conic sections and are capable of operating in the microwave and millimeter wave bands. By using the aperture method (ApM), a formulation to obtain the electric far field radiated by all classical configurations is also derived. Some case studies are analyzed by the method-of-moments (MoM) technique in order to validate the proposed GO-ApM analysis procedure.
  • Low Voltage Operated Current-Mode First-Order Universal Filter and
           Sinusoidal Oscillator Suitable for Signal Processing Applications
    • Abstract: Publication date: Available online 13 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Atul Kumar, Bhartendu Chaturvedi, Jitendra Mohan This paper introduces a current-mode first-order universal filter which is realized using single dual-X current conveyor transconductance amplifier and two capacitors only. The circuit configuration is appropriate to monolithic integration. The circuit enjoys benefits of low input and high output impedances making the circuit easily cascadable, electronically tunable pole frequency and low operating supply voltages. The non-ideal and parasitic analyses of the circuit are explored. The cascadability of proposed first-order filter is verified by realizing a second-order all-pass filter. Additionally, one application of proposed first-order universal filter in terms of voltage-mode sinusoidal oscillator is also presented. The oscillator circuit provides two 180° out of phase voltage signals, simultaneously. The output voltage signals are obtainable from low impedance terminals. To validate the proposed circuits, HSPICE simulations are depicted. Moreover, to explore the practical aspects of proposed circuits, experimental results of first-order universal filter for all-pass function and second-order all-pass filter, are carried out by using commercial chips.
  • Tunable Transmission-Line Transformer with Two Varactors and Its
           Application for Wilkinson Power Divider
    • Abstract: Publication date: Available online 13 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Xiaolong Wang, Naoki Shinoda, Zhewang Ma, Masataka Ohira A tunable transmission-line transformer (TLT) is newly introduced in this paper. It consists of two transmission lines (TLs), one parallel varactor and one series varactor. The design formulas are newly derived in closed-form, and its design procedure is also summarized in a flowchart. Because two TLs provide different characteristic impedances and electrical lengths, the tunable TLT can be designed much more flexible with different phase responses. By using this TLT topology, a novel Wilkinson power divider circuit could provide a wide tunable frequency range. The simulated and experimental S-parameters match very well. It is also proved that, although the phase responses of the proposed TLT are shifted from 77.22o to 90.72o in the tunable range 0.5 GHz - 1.3 GHz, its Wilkinson power divider application is still working well, and S22, S33 and S32 are still lower than – 20 dB in the total tunable range.
  • Ultra-wideband pose detection method based on TDOA positioning model for
           boom-type roadheader
    • Abstract: Publication date: Available online 13 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Shichen Fu, Yiming Li, Kai Zong, Chao Liu, Dan Liu, Miao Wu In deep and dangerous coal seam tunnelling, the autonomous navigation control system (ANCS) of the boom-type roadheader is the core that realises unattended work. The remote pose detection of the boom-type roadheader is the key task of the ANCS. In this study, an ultra-wide band (UWB) pose detection system (UPDS) for boom-type roadheaders is designed which realises the remote measurement of position and attitude parameters (heading, roll, and pitch angles) of the boom-type roadheader in a narrow and long enclosed roadway space. Based on the time difference-of-arrival (TDOA) positioning model, three UPDS positioning algorithms are proposed: Indirect positioning algorithm (IPA-D), Taylor series expansion algorithm (Taylor-D), and Chan positioning algorithm (Chan-D). A complete calculation process is deduced from the three UDPS positioning algorithms. Their accuracies are analysed based on the measured data of a P440 UWB ranging module in a narrow and long roadway. The positioning accuracy of IPA-D behaves better than those of Taylor-D and Chan-D: Within 95 m of the roadway, IPA-D can achieve values at a centimetre scale and the positioning error increases with increasing measurement distance. The calculated UPDS attitude angle error based on IPA-D increases with increasing measurement distance of up to 95 m; The roll angle error is approximately 0.05°, and the pitch and heading angles are approximately 0.15°. The presented UPDS meets the accuracy requirements for the pose detection of boom-type roadheaders in a fully mechanised excavation face and provides a reliable theoretical basis for ANCSs of boom-type roadheaders.
  • Horizontally Polarized Wideband Antenna Based on Quarter-Wavelength Slot
    • Abstract: Publication date: Available online 13 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Xi-Wang Dai, Guo-Qing Luo, Xiao Hong Zhang, Bin You, Hua Yan Jin A horizontally polarized (HP) wideband antenna is designed and analyzed for wireless communication in this communication. The HP antenna is a combination of four quarter-wavelength slot elements, and fed by a wideband power divider with equal amplitude and zero phase difference output signals. Equivalent to the current loop, four slot elements rotate around the center of proposed structure, which gives rise to a monopolar radiation pattern. A prototype is designed, fabricated and measured. The results show that a deep null more than 20dB appears in the broadside of the elevation plane radiation pattern. And a small ripple less than 2dB in azimuth plane radiation pattern is obtained. The antenna has a wide impedance band of 33.3% for S11
  • Miniaturized Circularly Polarized Patch Antenna Using Coupled Shorting
           Strip and Capacitive Probe Feed
    • Abstract: Publication date: Available online 12 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Hongyu Shi, Junwei Shi, Jianxing Li, Juan Chen, Zhiyuan Li, Shitao Zhu, Tayyab Ali Khan, Anxue Zhang This paper proposes a single-feed miniaturized circularly polarized (CP) patch antenna aimed to cover Chinese BeiDou navigation satellite system (BDS) B3 band (1268.52±10.23 MHz). Four unbalanced circular patches as perturbation elements are loaded onto corners of a square patch radiator to ensure CP property. To simultaneously realize miniature size and adequate CP bandwidth, each circular patch is coupled to an L-shaped shorting strip consisting of a horizontal arc-shaped strip connected to the ground plane through a vertical shorting pin. In addition, a capacitive probe feed fulfilled by embedding an annular gap is used to compensate large probe inductance due to thick substrate, and therefore good impedance matching can be obtained. The antenna occupies an overall size of λ0/8 × λ0/8 × λ0/13.6, where λ0 denotes the free space wavelength at 1268 MHz. Experimental results show that it achieves a 10-dB return loss impedance bandwidth of 75 MHz (1237 MHz – 1312 MHz) and a 3-dB axial ratio (AR) bandwidth of 31 MHz (1253 MHz – 1284 MHz). The measured 3-dB AR beamwidth and CP gain are above 170° and 4.0 dBic, respectively, across the entire BDS B3 band.
  • Optimum Beam Forming in Selective-relay Cooperative Communication Using
           Effective Capacity Approach
    • Abstract: Publication date: Available online 9 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Abdulhamid Zahedi Cooperative communication is a precious approach to overcome the interference of multiuser communication and increase data rate of communication system. Many papers are focused on this issue to achieve more efficiency of relay-based communication in view of QoS parameters. Effective capacity is a desired quality parameter that allows maximum constant data rate with guaranteeing delay. Beam forming coefficients are the main factors of transmitted power from relays and the purpose of the paper is to find maximum effective capacity due to the optimum beam forming coefficients allocated to the best-selected relays in Amplify and Forward (AF) strategy. Minimization of outage probability and transmitted power are the constraints of optimization process to keep the quality requirements. After considering effective capacity maximization and generating optimization problem, Lagrange multipliers are used to gain the optimum answer. Simulation results show that optimal power allocation is achievable using the proposed scheme which causes effective capacity maximization in cooperative communication system. Quantitatively stating, using the proposed method, BER is less than other similar AF or DF (Decode and Forward) cooperative strategies in similar systems. Moreover, the transmitted power is at least 1 dBw less than other efficient methods in larger SNR as shown in simulation results.
  • CPW-fed ultra-wideband slot antenna with broadband dual circular
    • Abstract: Publication date: Available online 8 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Zhenya Li, Xiaosong Zhu, Chengyou Yin A novel coplanar waveguide(CPW) fed ultra-wideband slot antenna with broadband dual circular polarization is proposed, fabricated and measured. The antenna structure is simple and consists of two CPW-fed ports to achieve both right-hand circular polarization and left-hand circular polarization at the same frequency band with the overall size of 48×48×1mm3. The design process of the proposed antenna is given and the circular polarization mechanism is analyzed from the surface current distribution. The variation of return loss, port isolation and axial ratio(AR) with antenna parameters is simulated. By optimizing the radiation patch and improving the ground plane, the ultra wide impedance bandwidth and broad axial ratio bandwidth are achieved. The measured impedance bandwidth is 153.1% (1.9-14.3GHz) with return loss better than 10dB, and the measured 3dB axial ratio bandwidth is 102.6% (1.9-5.9GHz). The gain and port isolation are better than 3dB and 15dB, respectively, within the AR band.
  • A new Approach for 10-bit Pipeline analog-to-digital converter Design
           based on 0.18 µm CMOS Technology
    • Abstract: Publication date: Available online 8 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Arash Rezapour, Mohammad Bagher Tavakoli, Farbod Setoudeh This paper presents a new structure for designing a pipeline analog-to-digital convertor with a speed of 100 MS/s, based on TSMC 0.18 µm CMOS technology. With this structure, we extracted primary bits from the input signal directly in the first block and sampling was also conducted in the same time. In this new structure that it used for Analog to Digital Converter (ADC) implementation, the first 3 bits are extracted simultaneously with sampling. The simulation results show that, the signal-to-noise ratio for a 10 MHz input is 54.4 dB and the total power consumption with power supply of 1.8 v is 19.7 mW.
  • Design of quad core photonic crystal fibers with flattened zero dispersion
    • Abstract: Publication date: Available online 7 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Pranaw Kumar, Vikash Kumar, Jibendu Sekhar Roy Two photonic crystal fiber structures with quad-core have been investigated in this paper. Both the structures are geometrically similar but have different background materials. Both PCF structures exhibit very high birefringence. However, structure with silica background material reports birefringence of the order 10-2. It is to be noted that, this PCF structure has also shown zero dispersion behavior over a wide range of telecommunication wavelength. Moreover, the other structure with lead silicate as background material has also reported very low dispersion. Thus both the PCF structures simulated show ability to mitigate the effect of polarized mode dispersion. Besides this, other propagation characteristics like confinement loss, normalized frequency and non linear coefficient have been reported.
  • Miniature microstrip Branch Line coupler with Folded Artifical Transmssion
    • Abstract: Publication date: Available online 7 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Denis Letavin The present work is devoted to the miniaturization of a conventional three branch line coupler device in UHF band. The procedure for designing miniature structures based on replacing the microstrip transmission line segment with equivalent structures with the same phase shift is described. These structures are placed in free space inside the coupler. The proposed coupler operates at 1 GHz (UHF band), with good specifications. The area of the manufactured prototype of the three-branch line coupler with open-circuit conditions stubs is 909 mm2, which is 76% less than the size of the conventional device and relative bandwidth is 23.7%. The area of the manufactured prototype of the three-branch line coupler with high-resistance lines with a high-resistance segment in the form of U symbol is 1169.7 mm2, which is 69.1% less than the size of the conventional device and relative bandwidth is 34.1%.
  • A new design procedure for wide band Doherty power amplifiers
    • Abstract: Publication date: Available online 7 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Mohammad Hadi Moradi Ardekani, Habibollah Abiri A generalized design procedure for Doherty power amplifier (DPA) with arbitrary output back-off power level (OBO) is proposed in this study. This method which covers many of previously reported configurations is employed to derive analytical formulas for a specific output combiner which is capable for absorbing parasitic elements of the main and auxiliary transistors. Combiner parameters can be adjusted to control operational frequency bandwidth at back-off and saturation. By considering parasitic elements in the design procedure, the needs for additional offset lines and CAD optimization are eliminated and efficiency does not degrade significantly at back-off. According to the proposed design methodology, a wide band DPA is designed, simulated and implemented with commercial packaged GaN transistor. Drain efficiency (DE) between 50-77 % at 6dB OBO and 57.5-80.4 % at saturation in the frequency band of 1.05 to 2.35 (GHz) (76.4 % fractional bandwidth) are achieved corresponding to the maximum output power and gain within 43-45.3 dBm and 11-13.3 dB, respectively. Gain fluctuation is lower than 0.6 dB for frequencies higher than 1.4 GHz. Combination of high efficiency, excellent power utilization factor and flat gain through an analytical design strategy introduces this method as a promising way to design wide band DPAs.
  • A tunable reflective analog predistorter based on variable impedance
           matching network
    • Abstract: Publication date: Available online 4 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Hailin Deng, Dewei Zhang, Dalong Lv, Dongfang Zhou, Yi Zhang This paper presents a modified reflective analog predistortion circuit to enable the tuning capability of gain and phase conversions. A variable impedance matching network based on varactor diode is introduced in the circuit to achieve the tuning function by changing its bias voltage. Based on this modified circuit, a tunable predistorter for traveling wave tube amplifier (TWTA) is designed and fabricated. The fabricated predistorter shows more than 5.5 dB tuning range of gain conversion and 49.0 ° tuning range of phase conversion in 29~31 GHz with the bias voltage varies from 0 V to 20 V. Good linearity enhancement has been obtained for a Ka-band TWTA with this predistorter.
  • Interference mitigation for a heterogeneous satellite network based on
           spatial angle and transmission power
    • Abstract: Publication date: Available online 3 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Pedram Hajipour, Ali Shahzadi, Saeed Ghazi-Maghrebi Nowadays, with the explosive growth of users and devices, it is expected that new generation satellite system will support different communication demand around the world. Therefore, by increasing demand, hybrid satellite-terrestrial networks have been developed for achieving more coverage and capacity. Thus, in this paper, a LEO satellite constellation is deployed which includes LEO satellite systems and terrestrial equipment. Also, in order to manage the interference that is one of the main challenges in this network, Stackelberg game theory is used based on power control between LEO satellite systems and mobile users. To mitigate interference, two sub-games are provided based on pricing-based algorithm and convex optimization method. Finally, simulation results show that the performance of heterogeneous satellite network will be enhanced by the presented assumptions.
  • A Bi-layered Chiral Metamaterial with High-Performance Broadband
           Asymmetric Transmission of Linearly Polarized Wave
    • Abstract: Publication date: Available online 3 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Farnaz Mirzamohammadi, Javad Nourinia, Changiz Ghobadi, Maryam Majidzadeh In this paper, a novel bi-layered chiral metamaterial (CMM) is presented to realize high–efficiency broadband asymmetric transmission (AT) of linearly polarized electromagnetic wave (EM) in the microwave region from 10.1GHz to 15.1GHz. For this purpose, a pair of modified resonators is employed on two sides of a thin dielectric substrate. The simulated and measured results confirm that linearly polarized wave in the form of x-polarized or y-polarized could be nearly converted into the orthogonal polarization after transmission through the introduced prototype which is affirmed by the polarization rotation azimuth angleθ. The polarization conversion ratio (PCR) is more than 92% at the mentioned frequency range. Full parametric simulation of modified resonators, azimuth rotation angle, and chirality parameter variable with frequency are discussed in detail. In addition, the surface current distributions of the structure have been demonstrated to investigate the physical mechanism of the cross-polarization and corresponding polarization conversion.
  • Beam Steered Linear Array of Cylindrical Dielectric Resonator Antenna
    • Abstract: Publication date: Available online 3 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Nipun K. Mishra, Soma Das, Dinesh K. Vishwakarma In the present work, linear array of four Cylindrical Dielectric Resonator Antenna having beam steering capability has been designed, investigated and validated experimentally. In order to achieve a specific progressive phase distribution, the phase coupled to each array element is controlled by changing the position of power junction feed point in the feeding network .Progressive phase shift between the elements have been achieved by the feeding network itself without the need of any phase shifter and biasing network hence making the array design simple and less costly. The proposed design with impedance bandwidth of 500MHz at 7.5GHz frequency along with the gain of nearly 10dBi could be used in radar communication and other wideband wireless applications operating in X-band for moving targets.
  • Investigation of the Pulse Radiating Performance of Resistively Loaded
           Dipole Antennas by Manipulation of the Loading Parameter
    • Abstract: Publication date: Available online 3 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Doojin Lee This paper presents the analysis of pulse radiating characteristics for variously loaded dipole antennas. The pulse radiating performance was investigated in a numerical and experimental study in terms of reflection of the feeding transmission line, radiating waveform with various angles, and transmission capacity. The calculated fidelity factor for a non-loaded dipole antenna, as well as R0/8, R0/4, R0/2 and R0loaded antennas, is 0.77, 0.81, 0.82, 0.85 and 0.87, respectively. The measured transmission characteristics, such as transmission coefficient, received waveform, boresight gain, phase response and group delay, have been explored in detail in terms of the loading parameter. A simple monostatic radar experiment of variously loaded antennas reveals that the amplitude of the reflected waveform and the second peak are closely related to the degree of the loading parameter.
  • Performance Analysis of Full-Duplex Decode-and-Forward Relay System with
           Energy Harvesting Over Nakagami-m Fading Channels
    • Abstract: Publication date: Available online 2 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Ba Cao Nguyen, Tran Manh Hoang, Phuong T. Tran In this paper, we analyze the performance of the full-duplex relay system, wherein two terminal nodes operate in the half-duplex mode and the relay node with decode-and-forward scheme operates in the full-duplex mode. We consider the replenishes energy from radio frequency (RF) for the source and the relay nodes through the power beacon (PB) combine with the case of imperfect self-interference cancellation (SIC) at the full-duplex relay. To increase the collected energy for the source and the relay, on the other hand decreasing the complexity for the high power amplifier at the PB, we assume that the PB has multiple antennas. Using theoretical analysis, we obtain the closed-form of the exact outage probability of the system over Nakagami-m fading channels. Furthermore, the exact expression for the symbol error probability of the system is derived to evaluate the system performance with different modulation schemes. Based on this analysis, the impact of the antenna numbers, m parameters, the time duration for harvesting and the residual self-interference are considered. The Monte-Carlo simulations are used to demonstrate the correctness of numerical results.
  • Memristor-Based Quinary Half Adder
    • Abstract: Publication date: Available online 1 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Ahmed H.Fouad, Ahmed G. Radwan This paper theorizes the possibilities of generalizing a memristor based ternary adder cir- cuit, to a memristor based multi-valued logic adder. The proposition tries to achieve the theoretical advantages of processing different numbering systems, increasing the density, and decreasing the processing time, by utilizing the memristor properties and dynamics. This is done using a memristor cell based circuit structure. The memristor is quantized to more levels in order to accommodate more values of logic being processed. Quinary numbering system is used to demonstrate the generalization, then a process of generalization is shown. Circuit modifications can be made to process different numbering systems.
  • Gain-Enhanced SIW Cavity-Backed Slot Antenna by Using TE410
           Mode Resonance
    • Abstract: Publication date: Available online 1 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Ziqiang Xu, Jiahao Liu, Si Huang, Yuanxun Li A gain-enhanced low profile substrate integrated waveguide (SIW) cavity-backed slot antenna is presented in this paper. By etching three parallel transverse slots on the center and both edges of the rectangular SIW cavity as the radiating elements, higher resonance mode of TE410 can be excited to achieve gain enhancement. Radiating mechanism and parameter effects of the three radiating slots have been investigated. Using the proposed multi-slot structures, an antenna is designed, fabricated and characterized, respectively. The fabricated antenna demonstrated a gain of 9.2 dBi, a front-to-back ratio of 17 dB, and a maximum cross-polarized radiation level of -19.7 dB at 10 GHz. Furthermore, the proposed antenna constructed using a single-layer printed circuit board (PCB) yields a better radiation performance and configuration advantage over that of the conventional planar antenna by taking advantage of the TE410 cavity resonance.
  • Error Probability Analysis of STBC-OFDM Systems with CFO and Imperfect CSI
           over Generalized Fading Channels
    • Abstract: Publication date: Available online 1 November 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Daljeet Singh, Hem Dutt Joshi In this paper, the closed form expressions of symbol error rate (SER) are derived for a space time block coded OFDM system subject to carrier frequency offset (CFO) under frequency-selective generalized fading scenarios. Apart from this, the effect of imperfect channel state information (CSI) is also taken into account for error rate analysis. The derived expressions are valid for any family of fading PDFs and the results of zero CFO with perfect CSI are found to be a special case. Numerical results are verified by extensive simulations.
  • Optimal Sensing, Fusion and Transmission with Primary User Protection for
           Energy-Efficient Cooperative Spectrum Sensing in CRNs
    • Abstract: Publication date: Available online 31 October 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Meenakshi Awasthi, Madhav J. Nigam, Vijay Kumar In this paper, energy efficiency for cooperative spectrum sensing in cognitive radio network is investigated and optimized. The novel mathematical formulation of energy efficiency maximization problem by considering number of secondary users, sensing time, and transmission time as design parameters with protection of primary user from SU transmission has been done. In order to solve the formulated problem, first the optimal expression for number of secondary users is formulated, then, an iterative sub optimal algorithm is proposed to obtain optimal sensing and transmission time. Numerical results and illustrative plots demonstrate the correctness and optimality of the proposed algorithm and show the improved performance over the state of arts.
  • Compact narrow/wide band branch-line couplers with improved upper-stopband
    • Abstract: Publication date: Available online 30 October 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Wei Nie, Kai-Da Xu, Mu Zhou, Liang-Bo Xie, Xiao-Long Yang This paper presents a class of compact narrow/wide band branch-line couplers with improved upper-stopband. Firstly, by analyzing stub-loaded transmission lines, it is found that the stub-loaded transmission line with a smaller size can be used to equivalently substitute the quarter-wavelength transmission line in the traditional branch-line coupler. As a result, the size of the branch-line coupler is significantly reduced. Furthermore, due to the transmission zero introduced by the open stub, the upper stopband is extended. Therefore a compact narrowband branch-line coupler with harmonic suppression can be realized. To validate the idea, the equivalent circuit model is developed, analytical closed-form equations are derived, and circuit simulation results are plotted for the analysis. Secondly, by adopting quarter-wavelength open-circuited coupled-lines at each port, a compact filtering wideband branch-line coupler with extended upper-stopband can be realized. Finally, the proposed couplers are fabricated to verify the design principles experimentally.
  • Compact Microstrip Antenna based on fractal Metasurface with low radar
           cross section and wide bandwidth
    • Abstract: Publication date: Available online 30 October 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Mahsa Ahmadi Rad, Mohammad Reza Soheilifar, Ferdows B. Zarrabi The compact antenna with wide bandwidth is important. In this paper, we have studied the microstrip slot antenna for wireless application based on the fractal structure which has covered 2.3 to 4 GHz (85% bandwidth). The circular slot antenna with four rectangular slots is considered and then six dual rings are added to the antenna. Finally, for improving the matching a disk is placed in the central part of the slot. The fractal model has been considered for low RCS, for improving the bandwidth, for amending the matching of the antenna by controlling the current distribution and it is modified for C-band application. The antenna gain is around 3.6 dB and around 90% efficiency with compact size 40×40 mm2 (0.3λ0×0.3λ0 at 2.5 GHz). The metasurface structure is reduced in the RCS around -15dB at 3.3 GHz. The antenna is simulated with two various numerical methods. The antenna is designed on FR4 as a low-cost substrate. The results show that the fractal shape is used for the bandwidth enhancement and experimental results are confirmed by our simulations. As a result, we show that how the metasurface combination with the antenna can be considered for improving the bandwidth and RCS simultaneously.
  • Analog and RF Assessment of Sub-20nm 4H-SiC Trench Gate MOSFET for High
           Frequency Applications
    • Abstract: Publication date: Available online 29 October 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Rishu Chaujar In this work, 4H-SiC Trench Gate (Recessed Channel) (4H-SiC-RC) MOSFET structure is demonstrated to have superior analog and RF Figure of Merits (FOMs) by numerical simulation. The integration of 4H-SiC with phosphorene contact on to the trench region results in higher drain current (2.3mA) and outstanding switching ratio (1016) owing to reduced off-current which leads to the lower sub-threshold slope (SS). Other electrical parameters such as electric field, electron mobility, and electron velocity are remarkably improved in 4H-SiC-RC MOSFET. Further, the high-frequency RF FOMs have also been studied, and it is observed that cut-off frequency (fT) gets doubled and maximum oscillator frequency (fMAX) increased by five times in the proposed design as compared to conventional design. Thus, the 4H-SiC-RC design is suitable for high switching, high power, and high-frequency application.
  • LOS identification for high accuracy TOA-based ranging system in tunnel
    • Abstract: Publication date: Available online 26 October 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Camelia Skiribou, Raja Elassali, Fouzia Elbahhar Boukour, Khalid Elbaamrani, Noureddine Idboufker, Aziz Benlarbi-Delai The performance of localization systems is highly sensitive to the presence of the Line-Of-Sight (LOS) path. In indoor environments, where high accuracy is required, identifying the channel conditions can be a good solution to overcome the multi-path effects and reduce the ranging error. Most of existing algorithms are based on the statistical parameters of the channel response or the range error. However, these features are limited when a single antenna is utilized. In this work, we exploit the spatial diversity of a multi-antenna system for LOS identification. In the future 5G devices, one powerful technique used for spectrum awareness is the Compressed Sensing (CS). Therefore, its implementation in our ranging system will allow us to obtain fine time resolution whilst avoiding an additional complexity in the receiver architecture. The proposed approach has been evaluated in tunnel environment and has efficiently improved the ranging accuracy.
  • A low-voltage highly linear OTA using bulk-driven floating gate MOSFETs
    • Abstract: Publication date: Available online 26 October 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Tanmay Dubey, Vijaya Bhadauria In this paper, a floating gate OTA using Flipped Voltage Follower (FG-FVF OTA) and its modified version with bulk-driven floating gate MOSFETs (BDFG-FVF OTA) are proposed. The FVF configuration is used to reduce the power consumption while the combination of bulk-driven and floating gate techniques is employed to enhance the linearity of the OTA. The proposed OTAs are compared with a floating gate OTA (FG OTA) to show the performance improvement. All the OTAs are designed and simulated in Candace Virtuoso tool using 0.18 μm CMOS process technology. The circuits are biased with ±0.5 V power supply. The simulation results show that the proposed BDFG-FVF OTA has less variation in transconductance for large range of input differential voltage as compared to FG OTA. BDFG-FVF OTA shows 8 dB improvement in HD3 for 0.2 Vpp differential voltage at 1 MHz frequency as compared to conventional FG OTA and its power consumption is 158 μW which is 36% lesser than that of FG OTA. All these improvements in proposed OTA are achieved at cost of 0.07% reduction in bandwidth. An application of proposed OTA is also presented in the form of universal Gm-C filter to ensure the workability of the proposed OTA.
  • An Ultra-Low Power, Low Voltage DC-DC Converter Circuit for Energy
           Harvesting Applications
    • Abstract: Publication date: Available online 23 October 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Elham Kordetoodeshki, Alireza Hassanzadeh In this paper a compact, fully-integrated voltage multiplier with a low start-up voltage is presented for energy harvesting applications. Two voltage doublers are cascaded with the overall conversion ratio of 2 and 4. The voltage multiplier has a 2-phase clock signal with a wide range of operating frequency from 1kHz to 1MHz. Cascading and positive feedback with cross-coupled gates have been used to increase the efficiency and conversion ratio of the converter. The DC-DC converter has an efficiency of more than 70% when operating from a 0.34V input voltage and generating 1.28V output voltage. The proposed voltage multiplier has a power consumption of 36nW to 1.24μW for input voltage range of 280mV to 450mV in 0.18μm CMOS technology.
  • Linear and Circular Polarization Radiation through a Modified 270 °
           Square Ring-Fed 2×2 Array Antenna
    • Abstract: Publication date: Available online 22 October 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Maryam Majidzadeh A novel design of a 2×2 array antenna with linear polarization (LP) and circular polarization (CP) characteristics is proposed. Each array elements is composed of a simple ground plane with an inverted L-shaped element and a modified radiating patch based on two inverted L-shaped components. The whole system is fed by a slotted feed line. The proposed single antenna operates over the frequency band of 3-4 GHz, 4.9-5.2 GHz, and 8-14 GHz, whiten which CP is seen at 3.5-4.5 GHz and LP is observed over the remained frequency bands. To improve the performance, four of aforementioned single antennas are arranged in a 2×2 array antenna. The feeding mechanism is developed based on a 270° square ring with varying widths in each quarter. Four branches, stemmed from the square ring, are connected to each of the constituent antenna elements for excitation purposes. Proper feeding strategy, suitable design of the elements positions, and wise-tuning of the dimensions of the antenna elements results in coverage of wide bandwidth ranging from 2.8-3.8 GHz, 4.5-7 GHz, and 7.3-8 GHz. As noticed, WiMAX and WLAN communication frequency bands are satisfactorily covered. Moreover, CP is attained at the frequency bands of 4.65-4.75 GHz and 5-7.2 GHz.
  • Outage Analysis for Multiuser Underlay Cognitive TWRN with Antenna
           Selection and User Scheduling
    • Abstract: Publication date: Available online 21 October 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Imtiyaz Khan, Poonam Singh This paper investigates the outage performance of cellular two-way amplify-and-forward (AF) cooperative spectrum sharing systems in the presence of primary user (PU) network and multiple secondary user (SU) destinations. A general Nakagami-m fading environment has been used, where distinct fading parameters, as well as unequal average fading powers between the interference and relaying links, are assumed. Focusing on the cooperation process among the SU nodes and making use of the underlay cognitive approach, an approximate closed-form expression for the overall outage probability (OOP) of the secondary network is derived. In this analysis, an opportunistic scheduling and transmit antenna selection (TAS) algorithm in the secondary network has been employed. Considering the interference constraints due to the presence of PU receiver, power allocation of secondary user is done. The effects of fading severity, secondary network relay placement, the number of PU & SU transmit antenna, and number of SUs on the end-to-end system performance are examined through some representative numerical plots. Moreover, to minimize the secondary network OOP, we investigate the optimization problems of relay position. Monte Carlo simulation results are presented to corroborate the proposed analysis.
  • Reconfigurable Chaotic Pseudo Random Number Generator based on FPGA
    • Abstract: Publication date: Available online 19 October 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Ahmed A. Rezk, Ahmed H. Madian, Ahmed G. Radwan, Ahmed M. Soliman This paper presents an FPGA Pseudo Random Number Generator (PRNG) that is based on the Lorenz and Lü chaotic systems. These two systems are used to generate four different 3D chaotic attractors. One attractor is generated from Lorenz while the other three attractors are generated from Lü. The output attractor of the proposed PRNG can be reconfigured during real time operation using an efficient hardwired shifting and multiplexing scheme. Furthermore, in order to exploit the proposed reconfiguration feature, the proposed PRNG has been embedded in an FPGA cascaded encryption processor that ciphers the input data from one up to four times successively. In each ciphering operation the PRNG is set to a new configuration and is initialized according to a part of the encryption key. The size of the encryption key can be varied according to the number of required ciphering operations. The proposed PRNG has been realized using VHDL, synthesized on Xilinx using the FPGA device XC5VLX50T, and analyzed using MATLAB and the NIST statistical suite. The proposed PRNG has utilized only 1.4 % from the FPGA’s slices, achieved an operating frequency up to 78 MHz, and successfully passed all the NIST statistical tests.
  • Effects of a Phantom Hand on a Non-Resonant Element for a 2.5 GHz
           Smartwatch Antenna
    • Abstract: Publication date: Available online 15 October 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Aurora Andújar, Yolanda Cobo, Jaume Anguera Smartwatches with wireless connectivity are becoming widely used and therefore, antenna engineering efforts are addressed to obtain small and efficient antenna systems. Since the space in a smartwatch is considerably small compared to other wireless devices, a non-resonant element of 12.0 mm x 3.0 mm x 2.4 mm for 2.4 GHz-2.5 GHz antenna system operation is proposed herein on a 30 mm x 30 mm ground plane. The ground clearance area is 14 mm x 5 mm, which leaves more space for facilitating the integration of other electronic components in the reduced ground plane area available for this kind of applications. Since the element is non-resonant, a matching network is used to match the antenna system when regarding the presence of a phantom hand.Several distances between the ground plane and the phantom hand are analyzed, from touching position to 6 mm distance. For each case, a new matching has been designed without the need of modifying the geometry of the antenna element. Measured total efficiency is in average (2.4 GHz-2.5 GHz) 15.1% for the worst case (touching position) and increases up to 37.0% for the 6mm case. These results are of practical interest to design smartwatch devices.
  • Fractional Order Integrator/Differentiator: FPGA implementation and FOPID
           Controller Application
    • Abstract: Publication date: Available online 13 October 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Mohammed F. Tolba, BahaaAlDeen M. AboAlNaga, Lobna A. Said, Ahmed H. Madian, Ahmed G. Radwan This paper introduces two FPGA based design approaches of the fractional order integrator and differentiator using Grünwald Letnikov (GL) definition where fixed window and linear approximation approaches are considered. The main advantage of the linear approximation method is that it reduces the huge memory of the fractional order systems. One of the top applications of fractional calculus is the fractional order Proportional Integral Derivative (FOPID) controller. It has gained a great attention in academic studies and in industrial applications. The proposed approaches have been used as building blocks to implement FOPID controller. Oscilloscope experimental results for several cases are presented for GL and the fractional order PID controller. The proposed designs have been implemented based on Verilog Hardware Description Language (HDL) and realized on Nexys 4 Artix-7 FPGA XC7A100T. Moreover, a comparison between the proposed FPGA Implementation results for the GL operator and previous work has been investigated.
  • A 28 GHz Four-Channel Phased-Array Transceiver in 65-nm CMOS Technology
           for 5G Applications
    • Abstract: Publication date: Available online 11 October 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Hesham A. Ameen, Kareem Abdelmonem, Mohamed A. Elgamal, Mohamed A. Mousa, Omaira Hamada, Yahia Zakaria, Mohamed A.Y. Abdalla A 28GHz fully integrated 4-channel TX/RX 5G beam-forming transceiver is implemented in 65-nm CMOS technology. Each TX/RX channel can be digitally controlled with 5.625° phase step and 2 dB gain step. The transceiver employs a heterodyne architecture with 6 GHz intermediate frequency (IF). The transciever works in a band of frequencies between 26GHz and 30GHz. The up/down-conversion mixers are integrated on the same chip with a shared LO chain. The phased-array power combining/splitting is done using a Wilkinson power combiner/divider. Each channel features 3.4 to 3.9 dB NF and -5 to -3.5 dBm IIP3 in RX mode, high OP1dB of 14.7 dBm and 18 dB gain in TX mode. The maximum rms amplitude and phase error for each channel is 0.25 dB and 1.5° across gain and phase states, respectively. The RFIC area is 5.29x3.4 mm2 including pads and it consumes 240 mW per channel in TX mode, 120 mW per channel in RX mode and 174 mW for the LO chain with a total power of 1.58 W from a 1.2 V supply.
  • A Compact Meta-atom Loaded Asymmetric Coplanar Strip-Fed Monopole Antenna
           for Multiband operation
    • Abstract: Publication date: Available online 10 October 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Rajeshkumar Venkatesan, Rajkumar Rengasamy, Praveen Vummadisetty. Naidu, Arvind Kumar In this paper, a compact asymmetric coplanar strip (ACS)-fed monopole antenna is presented. The proposed antenna consists of a tapered shaped radiating element and a meta-atom (complementary split ring resonator-CSRR), loaded in the ground plane which helps in obtaining multiband characteristics with proper impedance matching performance. Antenna with dimensions of 25 × 12.2 × 1.6 mm3 has been designed, fabricated and tested. The experimental result that exhibits of -10 dB impedance bandwidth by the proposed antenna at the center frequency of 2.88 GHz (1100 MHz), 5.78 GHz (1940 MHz) and 7.64 GHz (660 MHz). It covers wireless applications namely wireless local area network (WLAN) 2.4/5.2/5.8 GHz, long-term evolution (LTE) 2500 GHz, public safety applications 4.9 GHz, worldwide interoperability for microwave access (WiMAX) 5.5 GHz, wireless access for vehicular environments (WAVE) 5.9 GHz and X-band downlink frequency band 7.5 GHz. The antenna has good radiation characteristics in both E-plane and H-plane for all the operating frequencies. The proposed antenna exhibits a better performance compared to the previously reported designs to the existing antenna designs which are discussed in the literature. Moreover, the antenna possesses compact size, the total size occupied by the design is 0.20λ0 × 0.1λ0.
  • Design of Dual-band and High Gain Waveguide Slot Antenna
    • Abstract: Publication date: Available online 28 September 2018Source: AEU - International Journal of Electronics and CommunicationsAuthor(s): Dong-Ya Cheng, Jun Wang, Ya-Dong Wei, Chun-Yang Jin, Kai-Feng Cui, Min-Quan Li A new kind of dual-band and high gain waveguide slot antenna is designed in this paper. By combining a folded plate and a double-layer metal structure with four apertures on its top floor, the proposed antenna has a dual-band characteristic and its gain reaches up to 11.9dB with only 35 degrees (HPBW) of E-plane at 12.7GHz and 12.1dB with 39degrees at 15.0GHz. Compared to the conventional single-aperture flat antenna, the simulated and measured results show that the proposed antenna with resonant cavity achieves better impedance matching and low profile, meanwhile, the gain improved almost 5.2dB at 12.7GHz and 6dB at 15.0GHz, the HPBW of E-plane is reduced by 100 degrees and 108 degrees respectively.
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