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  Subjects -> ELECTRONICS (Total: 194 journals)
Showing 1 - 200 of 277 Journals sorted alphabetically
Acta Electronica Malaysia     Open Access  
Advanced Materials Technologies     Hybrid Journal  
Advances in Electrical and Electronic Engineering     Open Access   (Followers: 8)
Advances in Electronics     Open Access   (Followers: 94)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 8)
Advances in Power Electronics     Open Access   (Followers: 39)
Advancing Microelectronics     Hybrid Journal  
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (Followers: 353)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 27)
Annals of Telecommunications     Hybrid Journal   (Followers: 9)
APSIPA Transactions on Signal and Information Processing     Open Access   (Followers: 9)
Archives of Electrical Engineering     Open Access   (Followers: 14)
Australian Journal of Electrical and Electronics Engineering     Hybrid Journal  
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Batteries     Open Access   (Followers: 7)
Batteries & Supercaps     Hybrid Journal  
Bell Labs Technical Journal     Hybrid Journal   (Followers: 30)
Bioelectronics in Medicine     Hybrid Journal  
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 22)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 38)
Biomedical Instrumentation & Technology     Hybrid Journal   (Followers: 6)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 13)
BULLETIN of National Technical University of Ukraine. Series RADIOTECHNIQUE. RADIOAPPARATUS BUILDING     Open Access   (Followers: 1)
Bulletin of the Polish Academy of Sciences : Technical Sciences     Open Access   (Followers: 1)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 47)
China Communications     Full-text available via subscription   (Followers: 9)
Chinese Journal of Electronics     Hybrid Journal  
Circuits and Systems     Open Access   (Followers: 15)
Consumer Electronics Times     Open Access   (Followers: 5)
Control Systems     Hybrid Journal   (Followers: 301)
ECTI Transactions on Computer and Information Technology (ECTI-CIT)     Open Access  
ECTI Transactions on Electrical Engineering, Electronics, and Communications     Open Access   (Followers: 2)
Edu Elektrika Journal     Open Access   (Followers: 1)
Electrica     Open Access  
Electronic Design     Partially Free   (Followers: 123)
Electronic Markets     Hybrid Journal   (Followers: 7)
Electronic Materials Letters     Hybrid Journal   (Followers: 4)
Electronics     Open Access   (Followers: 104)
Electronics and Communications in Japan     Hybrid Journal   (Followers: 10)
Electronics For You     Partially Free   (Followers: 103)
Electronics Letters     Hybrid Journal   (Followers: 26)
Elkha : Jurnal Teknik Elektro     Open Access  
Embedded Systems Letters, IEEE     Hybrid Journal   (Followers: 55)
Energy Harvesting and Systems     Hybrid Journal   (Followers: 4)
Energy Storage     Hybrid Journal  
Energy Storage Materials     Full-text available via subscription   (Followers: 3)
EPE Journal : European Power Electronics and Drives     Hybrid Journal  
EPJ Quantum Technology     Open Access   (Followers: 1)
EURASIP Journal on Embedded Systems     Open Access   (Followers: 11)
Facta Universitatis, Series : Electronics and Energetics     Open Access  
Foundations and Trends® in Communications and Information Theory     Full-text available via subscription   (Followers: 6)
Foundations and Trends® in Signal Processing     Full-text available via subscription   (Followers: 10)
Frequenz     Hybrid Journal   (Followers: 1)
Frontiers of Optoelectronics     Hybrid Journal   (Followers: 1)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (Followers: 217)
Haptics, IEEE Transactions on     Hybrid Journal   (Followers: 4)
IACR Transactions on Symmetric Cryptology     Open Access  
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 100)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 81)
IEEE Journal of Emerging and Selected Topics in Power Electronics     Hybrid Journal   (Followers: 51)
IEEE Journal of the Electron Devices Society     Open Access   (Followers: 9)
IEEE Journal on Exploratory Solid-State Computational Devices and Circuits     Hybrid Journal   (Followers: 1)
IEEE Power Electronics Magazine     Full-text available via subscription   (Followers: 75)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 73)
IEEE Transactions on Automatic Control     Hybrid Journal   (Followers: 59)
IEEE Transactions on Circuits and Systems for Video Technology     Hybrid Journal   (Followers: 26)
IEEE Transactions on Consumer Electronics     Hybrid Journal   (Followers: 44)
IEEE Transactions on Electron Devices     Hybrid Journal   (Followers: 19)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 26)
IEEE Transactions on Power Electronics     Hybrid Journal   (Followers: 78)
IEEE Transactions on Signal and Information Processing over Networks     Full-text available via subscription   (Followers: 13)
IEICE - Transactions on Electronics     Full-text available via subscription   (Followers: 12)
IEICE - Transactions on Information and Systems     Full-text available via subscription   (Followers: 5)
IET Cyber-Physical Systems : Theory & Applications     Open Access   (Followers: 1)
IET Energy Systems Integration     Open Access  
IET Microwaves, Antennas & Propagation     Hybrid Journal   (Followers: 35)
IET Nanodielectrics     Open Access  
IET Power Electronics     Hybrid Journal   (Followers: 57)
IET Smart Grid     Open Access  
IET Wireless Sensor Systems     Hybrid Journal   (Followers: 18)
IETE Journal of Education     Open Access   (Followers: 4)
IETE Journal of Research     Open Access   (Followers: 11)
IETE Technical Review     Open Access   (Followers: 13)
IJEIS (Indonesian Journal of Electronics and Instrumentation Systems)     Open Access   (Followers: 3)
Industrial Electronics, IEEE Transactions on     Hybrid Journal   (Followers: 74)
Industrial Technology Research Journal Phranakhon Rajabhat University     Open Access  
Industry Applications, IEEE Transactions on     Hybrid Journal   (Followers: 38)
Informatik-Spektrum     Hybrid Journal   (Followers: 2)
Instabilities in Silicon Devices     Full-text available via subscription   (Followers: 1)
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (Followers: 13)
International Journal of Advanced Research in Computer Science and Electronics Engineering     Open Access   (Followers: 18)
International Journal of Advances in Telecommunications, Electrotechnics, Signals and Systems     Open Access   (Followers: 12)
International Journal of Antennas and Propagation     Open Access   (Followers: 11)
International Journal of Applied Electronics in Physics & Robotics     Open Access   (Followers: 4)
International Journal of Computational Vision and Robotics     Hybrid Journal   (Followers: 5)
International Journal of Control     Hybrid Journal   (Followers: 11)
International Journal of Electronics     Hybrid Journal   (Followers: 7)
International Journal of Electronics and Telecommunications     Open Access   (Followers: 13)
International Journal of Granular Computing, Rough Sets and Intelligent Systems     Hybrid Journal   (Followers: 3)
International Journal of High Speed Electronics and Systems     Hybrid Journal  
International Journal of Hybrid Intelligence     Hybrid Journal  
International Journal of Image, Graphics and Signal Processing     Open Access   (Followers: 16)
International Journal of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 10)
International Journal of Nanoscience     Hybrid Journal   (Followers: 1)
International Journal of Numerical Modelling: Electronic Networks, Devices and Fields     Hybrid Journal   (Followers: 4)
International Journal of Power Electronics     Hybrid Journal   (Followers: 25)
International Journal of Review in Electronics & Communication Engineering     Open Access   (Followers: 4)
International Journal of Sensors, Wireless Communications and Control     Hybrid Journal   (Followers: 10)
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 4)
International Journal of Wireless and Microwave Technologies     Open Access   (Followers: 6)
International Transaction of Electrical and Computer Engineers System     Open Access   (Followers: 2)
JAREE (Journal on Advanced Research in Electrical Engineering)     Open Access  
Journal of Biosensors & Bioelectronics     Open Access   (Followers: 4)
Journal of Advanced Dielectrics     Open Access   (Followers: 1)
Journal of Artificial Intelligence     Open Access   (Followers: 12)
Journal of Circuits, Systems, and Computers     Hybrid Journal   (Followers: 4)
Journal of Computational Intelligence and Electronic Systems     Full-text available via subscription   (Followers: 1)
Journal of Electrical and Electronics Engineering Research     Open Access   (Followers: 36)
Journal of Electrical Bioimpedance     Open Access  
Journal of Electrical Bioimpedance     Open Access   (Followers: 2)
Journal of Electrical Engineering & Electronic Technology     Hybrid Journal   (Followers: 7)
Journal of Electrical, Electronics and Informatics     Open Access  
Journal of Electromagnetic Analysis and Applications     Open Access   (Followers: 8)
Journal of Electromagnetic Waves and Applications     Hybrid Journal   (Followers: 9)
Journal of Electronic Design Technology     Full-text available via subscription   (Followers: 6)
Journal of Electronics (China)     Hybrid Journal   (Followers: 5)
Journal of Energy Storage     Full-text available via subscription   (Followers: 4)
Journal of Engineered Fibers and Fabrics     Open Access   (Followers: 2)
Journal of Field Robotics     Hybrid Journal   (Followers: 3)
Journal of Guidance, Control, and Dynamics     Hybrid Journal   (Followers: 182)
Journal of Information and Telecommunication     Open Access   (Followers: 1)
Journal of Intelligent Procedures in Electrical Technology     Open Access   (Followers: 3)
Journal of Low Power Electronics     Full-text available via subscription   (Followers: 10)
Journal of Low Power Electronics and Applications     Open Access   (Followers: 10)
Journal of Microelectronics and Electronic Packaging     Hybrid Journal  
Journal of Microwave Power and Electromagnetic Energy     Hybrid Journal   (Followers: 3)
Journal of Microwaves, Optoelectronics and Electromagnetic Applications     Open Access   (Followers: 11)
Journal of Nuclear Cardiology     Hybrid Journal  
Journal of Optoelectronics Engineering     Open Access   (Followers: 4)
Journal of Physics B: Atomic, Molecular and Optical Physics     Hybrid Journal   (Followers: 30)
Journal of Power Electronics & Power Systems     Full-text available via subscription   (Followers: 11)
Journal of Semiconductors     Full-text available via subscription   (Followers: 5)
Journal of Sensors     Open Access   (Followers: 26)
Journal of Signal and Information Processing     Open Access   (Followers: 9)
Jurnal ELTIKOM : Jurnal Teknik Elektro, Teknologi Informasi dan Komputer     Open Access  
Jurnal Rekayasa Elektrika     Open Access  
Jurnal Teknik Elektro     Open Access  
Jurnal Teknologi Elektro     Open Access  
Kinetik : Game Technology, Information System, Computer Network, Computing, Electronics, and Control     Open Access  
Learning Technologies, IEEE Transactions on     Hybrid Journal   (Followers: 12)
Magnetics Letters, IEEE     Hybrid Journal   (Followers: 7)
Majalah Ilmiah Teknologi Elektro : Journal of Electrical Technology     Open Access   (Followers: 2)
Metrology and Measurement Systems     Open Access   (Followers: 6)
Microelectronics and Solid State Electronics     Open Access   (Followers: 28)
Nanotechnology Magazine, IEEE     Full-text available via subscription   (Followers: 42)
Nanotechnology, Science and Applications     Open Access   (Followers: 6)
Nature Electronics     Hybrid Journal   (Followers: 1)
Networks: an International Journal     Hybrid Journal   (Followers: 5)
Open Electrical & Electronic Engineering Journal     Open Access  
Open Journal of Antennas and Propagation     Open Access   (Followers: 9)
Optical Communications and Networking, IEEE/OSA Journal of     Full-text available via subscription   (Followers: 16)
Paladyn. Journal of Behavioral Robotics     Open Access   (Followers: 1)
Power Electronics and Drives     Open Access   (Followers: 2)
Problemy Peredachi Informatsii     Full-text available via subscription  
Progress in Quantum Electronics     Full-text available via subscription   (Followers: 7)
Pulse     Full-text available via subscription   (Followers: 5)
Radiophysics and Quantum Electronics     Hybrid Journal   (Followers: 2)
Recent Advances in Communications and Networking Technology     Hybrid Journal   (Followers: 4)
Recent Advances in Electrical & Electronic Engineering     Hybrid Journal   (Followers: 10)
Research & Reviews : Journal of Embedded System & Applications     Full-text available via subscription   (Followers: 5)
Revue Méditerranéenne des Télécommunications     Open Access  
Security and Communication Networks     Hybrid Journal   (Followers: 2)
Selected Topics in Applied Earth Observations and Remote Sensing, IEEE Journal of     Hybrid Journal   (Followers: 56)
Semiconductors and Semimetals     Full-text available via subscription   (Followers: 1)
Sensing and Imaging : An International Journal     Hybrid Journal   (Followers: 2)
Services Computing, IEEE Transactions on     Hybrid Journal   (Followers: 4)
Software Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 79)
Solid State Electronics Letters     Open Access  
Solid-State Circuits Magazine, IEEE     Hybrid Journal   (Followers: 13)
Solid-State Electronics     Hybrid Journal   (Followers: 9)
Superconductor Science and Technology     Hybrid Journal   (Followers: 3)
Synthesis Lectures on Power Electronics     Full-text available via subscription   (Followers: 3)
Technical Report Electronics and Computer Engineering     Open Access  
TELE     Open Access  
Telematique     Open Access  
TELKOMNIKA (Telecommunication, Computing, Electronics and Control)     Open Access   (Followers: 9)
Transactions on Electrical and Electronic Materials     Hybrid Journal   (Followers: 1)
Universal Journal of Electrical and Electronic Engineering     Open Access   (Followers: 7)
Ural Radio Engineering Journal     Open Access   (Followers: 1)
Visión Electrónica : algo más que un estado sólido     Open Access   (Followers: 1)
Wireless and Mobile Technologies     Open Access   (Followers: 6)
Wireless Power Transfer     Full-text available via subscription   (Followers: 4)
Women in Engineering Magazine, IEEE     Full-text available via subscription   (Followers: 11)
Електротехніка і Електромеханіка     Open Access  

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Similar Journals
Journal Cover
IEEE Antennas and Wireless Propagation Letters
Journal Prestige (SJR): 1.047
Citation Impact (citeScore): 4
Number of Followers: 81  
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1536-1225
Published by IEEE Homepage  [191 journals]
  • IEEE Antennas and Wireless Propagation Letters
    • Abstract: Provides a listing of current staff, committee members and society officers.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Miniaturized UHF/UWB Tag Antenna for Indoor Positioning Systems
    • Authors: Xiaoyong Shan;Zhongxiang Shen;
      Pages: 2453 - 2457
      Abstract: A miniaturized ultrahigh frequency (UHF)/ultra-wideband (UWB) dual-band tag antenna with a geometrical dimension of 34.6 mm × 21.5 mm × 6 mm is presented for indoor real-time positioning systems. A small patch is employed as the UWB radiator, and two U-shaped striplines are used for the UHF band. A quarter-wavelength metallic strip is introduced under the UWB patch to create an extra resonance to further expand the operation bandwidth. The antenna is backed by a ground plane to reduce the backside radiation and to improve the antenna gain in the UWB band. The measured bandwidth covers the frequency range from 919 to 931 MHz in the UHF band and 3.28 to 6.95 GHz in the UWB band with VSWR better than 2:1. The measured radiation patterns within the above-mentioned UHF and UWB frequency bands are very stable. The attractive features of compact size and wide bandwidth make it a very competitive candidate of tag antenna for indoor positioning systems.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Plastic-Filled Dual-Polarized Lens Antenna for Beam-Switching in the
    • Authors: Resti Montoya Moreno;Juha Ala-Laurinaho;Ville Viikari;
      Pages: 2458 - 2462
      Abstract: This letter presents a circular lens antenna for wide-angle beam steering and for dual-polarized operation at millimeter-wave (mm-wave) frequencies (27–30 GHz). The lens consists of a dielectric disc and two parallel plates, whose vertical spacing is varied linearly to achieve a suitable effective refraction index profile for the polarization parallel to the plates. The desired refraction profile is that of the Luneburg lens. The variation in plate spacing has negligible effect on the polarization perpendicular to the plates, and therefore, the dielectric material is selected such that the circular shape of the lens approximates the dimensions of the extended hemispherical lens. This way, the lens provides focusing or collimation for both linear polarizations. The lens is fed with square waveguides supporting both polarizations. Several feeding waveguides allow beam switching over a wide angular range. The designed lens antenna was fabricated, and the simulation and measurement results agree well and show that the proposed antenna concept is a valid solution for the upcoming 5G technologies, for instance as the access-point antenna. The antenna provides a $pm text{50}{^circ }$ beam-scanning range in both polarizations, and the realized gain is mostly between 9 and 12 dBi for the main beam. The measured reflection coefficient is mainly below $-$10 dB for both polarizations across the whole frequency band.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • High-Transmittance Absorptive Structure Based on Effect of
           Electromagnetically Induced Transparency
    • Authors: Zhefei Wang;Jiahui Fu;Qingsheng Zeng;Mingxin Song;Tayeb Ahmed Denidni;
      Pages: 2463 - 2467
      Abstract: In this letter, a novel absorptive structure with a high-transmittance bandpass behavior is proposed based on the electromagnetically induced transparency-like effect. The desired response is achieved by employing cascaded lossy π-shaped and lossless dual-band reflective arrays. The lossy array consists of radiative and subradiant resonators. A resistor is loaded on the radiative resonator to consume the excited current within the stopband. The bright-dark mode coupling contributes to a transparency window with an insertion loss of 0.07 dB. By combining with the reflective array, two absorption bands are obtained at both sides of the passband, and the maximum absorptivity is above 98%. Meanwhile, the 10 dB reflection reduction behavior is realized within the operating band, and a good stealth performance is provided. The fabricated prototype is measured, and the simulation and experimental results are in a good agreement.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • A Closed-Form Formula of Radiation and Total Efficiency for Lossy
           Multiport Antennas
    • Authors: Min Wang;Tian-Hong Loh;Yongjiu Zhao;Qian Xu;
      Pages: 2468 - 2472
      Abstract: This letter proposes a closed-form expression of the radiation and the total efficiency for the entire lossy multiport antenna system with simultaneous excitations. The equivalent circuit model and the detailed analysis process of the two-element lossy multiport antennas as well as a generalized expression for N-element lossy multiport antennas were considered. The required inputs to the closed-form expression are S-parameters, embedded radiation efficiency of each antenna element, and radiation efficiency of the entire antenna pair with identical simultaneous excitations. This method can be used for the analysis of multiple-input–multiple-output (MIMO) and antenna arrays, when the multiple elements are simultaneously excited with arbitrary amplitude and phase. To validate the proposed method, two different lossy MIMO antennas, namely, a pair of parallel end-fed dipoles and 4 × 1 layout printed bowtie antennas, were studied with various amplitude- and phase-feeding schemes. Full-wave numerical simulations were performed to provide inputs to the closed-form expression. Excellent agreement was observed between the radiation efficiencies of these antennas obtained through the closed-form expression and the full-wave numerical simulations, which demonstrates accuracy of the proposed closed-form expression. Furthermore, the proposed method can significantly reduce the total number of measurements for charactering the efficiency of the entire simultaneously excited lossy multiport antennas.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Low-Profile Circularly Polarized Patch Antenna With Wide 3 dB Beamwidth
    • Authors: Mrityunjoy Kumar Ray;Kaushik Mandal;Nasimuddin Nasimuddin;
      Pages: 2473 - 2477
      Abstract: In this letter, a low-profile circularly polarized (CP) narrow-slots slotted-patch antenna for wide 3 dB axial-ratio beamwidth (ARBW) performance is presented. It consists of two pairs of narrow slots along the diagonal lines of a square patch with a single feed. These pairs of narrow slots are conceived and placed to serve as magnetic dipoles with quarter-wavelength separation, forcing the amplitude of the orthogonal electric field components to be equal across a wide angle. The 3 dB ARBW of the CP antenna is a strong function of the mutual magnetic field, which is feasible to alter with different parameters of the slot. The location, dimensions, and gap between the slots are tuned to achieve wide 3 dB ARBW. Measured results of the fabricated prototype exhibit 3 dB ARBW of 226° with ARmin of 0.52 dB and 198° with ARmin of 1.61 dB in two principal planes at $boldsymbol{varphi } = text{0}^circ $ and $boldsymbol{varphi } = text{90}^circ $, respectively. The antenna offers impedance bandwidth of 85 MHz (2.448–2.533 GHz) and CP bandwidth (CPBW) of 23 MHz (2.474–2.497 GHz). The minimum peak gain is 3.87 dBic in the broadside direction.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Channel Correlation-Based Approach for Feedback Overhead Reduction in
           Massive MIMO
    • Authors: Frédéric Challita;Pierre Laly;Marwan Yusuf;Emmeric Tanghe;Wout Joseph;Pierre Degauque;Martine Liénard;Davy P. Gaillot;
      Pages: 2478 - 2482
      Abstract: For frequency-division duplex multiple-input–multiple-output (MIMO) systems, the channel state information at the transmitter is usually obtained by sending pilots or reference signals from all elements of the antenna array. The channel is then estimated by the receiver and communicated back to the transmitter. However, for massive MIMO, this periodical estimation of the full transfer matrix can lead to prohibitive overhead. To reduce the amount of data, we propose to estimate the updated channel matrix from the knowledge of the full correlation matrix at the transmitter made during some initialization time and the instantaneous measured channel matrix of smaller size, characterizing the link between the user and a limited number of reference array elements. The proposed algorithm is validated with measured massive MIMO channel transfer functions at 3.5 GHz between a $9 times 9$ uniform rectangular array and different user positions. Since measurements were made in static conditions, the criteria chosen for evaluating the performance of the algorithm are based on a comparison of the predicted channel capacity calculated from either the measured or estimated channel matrix.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • On the Contribution of Dense Multipath Components in an Intrawagon
           Environment for 5G mmW Massive MIMO Channels
    • Authors: Frédéric Challita;Vicent M. Rodrigo-Peñarrocha;Lorenzo Rubio;Juan Reig;Leandro Juan-Llácer;Juan Pascual-García;José-María Molina-García-Pardo;Martine Liénard;Davy P. Gaillot;
      Pages: 2483 - 2487
      Abstract: In this letter, the dependence of the specular multipath components (SMC) and dense multipath components (DMC) to the interuser spatial correlation and sum-rate capacity of a massive multiuser multiple-input--multiple-output (MU-MIMO) setup is evaluated from measurements conducted inside an underground subway wagon at the 25–40 GHz candidate frequency bands for 5G systems. The radio channel consists in a 7 × 7 uniform rectangular array (URA) acting as access point for eight users uniformly distributed in the wagon. The DMC power ratio is observed to be distance- and frequency-dependent as the SMC and DMC exhibit different propagation mechanisms. Remarkably, it is reported that the interuser spatial correlation computed with DMC offers the best favorable propagation for a massive MIMO setup, whereas SMC contribute to the users correlation. Hence, correlation is found to be strongly dependent on the DMC ratio frequency characteristics. In addition, better interuser correlation and sum-rate capacity values are obtained as the frequency is increased. These results highlight the need to include DMC in 5G massive MIMO channel models and emulators to improve their accuracy at the system level.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • A Two-Dimensional Multibeam Lens Antenna for Hydrologic Radar Application
    • Authors: Bing Zhang;Li Wu;Yanping Zhou;Yang Yang;Huacheng Zhu;Fei Cheng;Qian Chen;Kama Huang;
      Pages: 2488 - 2492
      Abstract: A K-band multibeam lens antenna is reported for hydrological radar applications. It is designed with a shared aperture and drifted feeds on elevation and azimuth. The feeds shift off the focal point of the lens onto a planar plane, which generates multibeam by refraction, meanwhile easing the mounting of the lens on a smooth surface. A conical horn array is designed as the feed for increased gain and better power capacity. Both dielectric and metallic three-dimensional printing technologies are adopted for fabrication. Measurement results agree with simulation, showing an impedance bandwidth of 18–25 GHz. The boresight gain lies in the range of 24–29 dBi. It radiates seven beams ±34° symmetrically on elevation and azimuth. Mutual coupling between adjacent ports is below −30 dB. The proposed multibeam lens enriches the choices for hydrological radar applications, in which a large area or multiple targets shall be looked upon from distance away.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Composite Scattering Analysis of the Ship on a Rough Surface Based on the
           Forward Parametric Scattering Center Modeling Method
    • Authors: Kai Huang;Si-Yuan He;Yun-Hua Zhang;Hong-Cheng Yin;Zhi-Dan Bian;Guo-Qiang Zhu;
      Pages: 2493 - 2497
      Abstract: A novel forward method to establish the three-dimensional parametric scattering center models is developed to extract scattering centers from the combined target/rough surface models. Both scattering centers from the ship, including single-order and higher order scattering contributions, and from the multiple interactions between the ship and random rough sea surface would be described concisely with physically relevant parameters by this proposed method. Due to the statistical nature of the random rough surface for the Monte Carlo simulation, we acquire a large number of realizations for estimations of the amplitude and position parameters to overcome the problem that single realization cannot extract scattering centers effectively. This method is validated through parametric models of the ship in free space and on the sea surface, and a good agreement has been demonstrated between the constructed and simulated radar characteristics. Furthermore, we analyze the composite target/surface model's physics and feature stability in a visually spatial range and direct connections between scattering centers and scattering sources, which would be valuable to future target recognitions and classifications. Finally, we quantitatively calculate and analyze the coupling scattering centers from interactions between the ship and the ocean-like surface that provide more abundant contour information of the inverse synthetic aperture radar (ISAR) image to facilitate contour detections.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Differentially Inserted-Fed Compact Dual-Band Circularly Polarized
           Dielectric Resonator Antenna
    • Authors: Chang-Wu Tong;Hui Tang;Wei Qin;Wen-Wen Yang;Xue-Feng Zhang;Jian-Xin Chen;
      Pages: 2498 - 2502
      Abstract: In this letter, a differentially inserted-fed compact dual-band circularly polarized dielectric resonator antenna (DRA) is proposed. To realize a compact design, the inserted differential feeding structure composed of a pair of arc-shaped strips connecting with coaxial probes plays dual roles. It not only excites the fundamental mode HEM111 of the DRA, but also brings an additional resonant mode to form the second band. Besides, the lower and upper bands of the DRA are independently controlled by the DR and the strips, facilitating the design process of the dual-band DRA. For demonstration, a prototype is designed, fabricated, and measured. Measured results show that the proposed DRA with the profile of 0.34 $lambda _{g}$ achieves impedance bandwidth (|Sdd11|
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • A Low-Profile Third-Order Half-Mode SIW Filtering Antenna With Low H-Plane
           Cross Polarization and Good Sideband Suppression
    • Authors: Lei Li;Di Pang;Yongbo Feng;Qing Wang;Zhenya Lei;
      Pages: 2503 - 2507
      Abstract: A new type of low-profile filter antenna with low H-plane cross polarization (cross-pol) and good suppression of sidebands is proposed using multifunction single slot and five shorting pins integrated into half-mode substrate integrated waveguide (SIW). Initially, the TM1,3/2 mode, the TM1,5/2 mode, and the TM3,1/2 mode have been excited successively in the low H-plane cross-pol SIW. Then, in order to realize third-order half-mode radiation of the antenna, the five shorting pins and the key slot have been used to reallocate those modes above. In addition, the slot also introduces two transmission zeros at 4.94 and 6.12 GHz to improve the filtering characteristic and to suppress the sidebands of the antenna. Finally, the filtering antenna is designed at 5.16 GHz with 2.5% impedance bandwidth for WLAN wireless communication application. The attenuation for lower sideband is always below 30 dBi, while the corresponding bandwidth for upper sideband achieves high out-of-band suppression levels of 20 dBi is about 1.52 GHz. The cross polarization can reach below –30 dB; meanwhile, its gain in frequency band is 6.79 dBi above. In addition, the low-profile property has been obtained with the height of 0.0087 free-space wavelength.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Switchable Broadband Dual-Polarized Frequency-Selective
    • Authors: Guangxu Qian;Junming Zhao;Xiaomei Ren;Ke Chen;Tian Jiang;Yijun Feng;Ying Liu;
      Pages: 2508 - 2512
      Abstract: This letter presents a switchable dual-polarized frequency-selective rasorber/absorber at low microwave frequency based on double-layered metallic resonant structure array loaded with lumped elements. It consists of an absorbing layer and a bandpass frequency-selective surface layer loaded with PIN diodes, sandwiched with an air-spacer between them. The operating principle is analyzed with the help of an equivalent circuit model. By biasing the PIN diodes on or off, it can be easily switched between the rasorber and absorber modes. When in the rasorber mode, it exhibits a passband at 1.6 GHz with 1.7 dB insertion loss between two neighboring absorption bands. While switched to the absorber mode, it achieves more than 80% absorptivity ranging from 0.8 to 3.4 GHz, corresponding to a fractional bandwidth of 124%. The total thickness is less than 8% of the free-space wavelength at the lowest operating frequency. A prototype of the proposed structure is fabricated and measured, where reasonable agreements between simulations and measurements are observed.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Finger-Worn UHF Far-Field RFID Tag Antenna
    • Authors: Paul S. Taylor;John C. Batchelor;
      Pages: 2513 - 2517
      Abstract: This letter presents the design and measurement of an experimental passive UHF radio frequency identification (RFID) tag worn as a ring with applications particularly in healthcare or secure environments. Three sizes of rings were designed for the European UHF RFID band over two different substrates at varying heights off the skin. Designing effective body-mounted antennas for passive RFID is very challenging, particularly when mounted directly upon the skin. The rings were simulated with a commercial electromagnetic simulation software and then constructed and tested on an adult male ring finger over several angles of RF illumination so that read ranges and directivity could be determined. Main beam read distances between 2 and 5 m were achieved dependent on the ring substrate height.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Thin-Profile Wideband and High-Gain Microstrip Patch Antenna on a Modified
    • Authors: Jean de Dieu Ntawangaheza;Liguo Sun;Chen Yang;Yingying Pang;Gerard Rushingabigwi;
      Pages: 2518 - 2522
      Abstract: A low-profile, high-gain, and broadband U-slot cut artificial magnetic conductor (AMC) loaded patch antenna is presented in this letter. The wideband performance is achieved by strategically cutting two rectangular slots and inserting four strips onto a conventional AMC ground plane. Moreover, a defected ground structure is used to reduce the antenna size. As a result, four reflection zeroes are obtained within the antenna |$S_{11}$| curve. The antenna is characterized by a low profile ($boldsymbol{h}/{boldsymbol{lambda }_0}sim 0.05$, ${boldsymbol{lambda }_0}$ is the free-space wavelength at the center frequency), wide bandwidth 58.6%, light weight, low cost, and wide 10 dBi gain bandwidth. The presented antenna is suitable for C-band satellite (3.7–4.2 GHz), 5.15–5.35 GHz WLAN, and the 5G in 3–6 GHz band applications.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • A Compact Circularly Polarized Antenna With Directional Pattern for
           Wearable Off-Body Communications
    • Authors: Ubaid Ullah;Ismail Ben Mabrouk;Slawomir Koziel;
      Pages: 2523 - 2527
      Abstract: This letter presents a geometrically simple and compact circularly polarized antenna with unidirectional radiation characteristics for off-body communications. The proposed antenna is based on a microstrip-line monopole extension from a coplanar waveguide and a protruded stub from one side of the coplanar ground plane along the length of the monopole. The orthogonal components of equal amplitudes required for circular polarization are induced using the vertical stub and the horizontal edge of the coplanar ground plane. To control the radiation of the antenna towards the human body, a flexible, high-permittivity laminated substrate is used as a reflector. The topological simplicity of the antenna permits a small number of adjustable variables and therefore a reduced computational cost of the parameter tuning process. The total footprint of the proposed antenna is only $0.23lambda _{o},times, 0.24lambda _{o}$ = 0.05 $boldsymbol{lambda }_{bf{o}}^2$ at the lowest operating frequency. The antenna is numerically and experimentally characterized in the free space and on a real human volunteer. The simulated and measured reflection coefficient indicates that the operating range of the antenna extends from 5.16 to 6.13 GHz range with 100% bandwidth overlap between the impedance bandwidth and the axial-ratio bandwidth. The peak gain of the antenna is 6.22 dBic with a stable radiation pattern in the +z-direction, high efficiency of 90%, and 0.131 W/g specific absorption rate (SAR). The antenna can be used for Unlicensed National Information Infrastructure (U-NII) worldwide band and Industrial, Scientific, and Medical (ISM) 5.8 GHz band.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • A Simplified Model for Predicting the Installed Performance of Circularly
           Polarized Antennas
    • Authors: Igor A. Baratta;Alexis F. Tinoco-S.;Elson Jose Silva;
      Pages: 2528 - 2532
      Abstract: We propose a simplified equivalent model for predicting the installed performance of circularly polarized (CP) antennas. We use a set of infinitesimal sources to represent the irradiated fields of an antenna of interest; however, instead of using infinitesimal dipoles, our source is composed of a set of infinitesimal crossed dipoles, the most basic radiator that generates CP waves. This choice facilitates the optimization process and still maintains the analytical aspect of the model; the irradiated fields can be described analytically. We achieve a reduction in computational cost when comparing to direct modeling, without impairing the accuracy of the model during the antenna placement task, and a reduction of optimization time when comparing to classical dipole models. Also, the equivalent model building step has reduced a computational cost for CP antennas. In order to validate our model, we construct a scaled model of a circular cylinder with a top-mounted GPS antenna, and we measure its radiation pattern in an anechoic chamber. The experimental results are in remarkable agreement with those simulated using the proposed equivalent model.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Dual-Beam Periodic Leaky-Wave Antenna With Reduced Beam Squinting
    • Authors: Yuefeng Hou;Yue Li;Zhijun Zhang;Zhenghe Feng;
      Pages: 2533 - 2537
      Abstract: In this letter, a dual-beam periodic leaky-wave antenna with a low beam-squinting character is presented. It has a simple and low-profile configuration, which consists of 15 slot radiating elements and one microstrip feedline. The slot radiating element creates nulls in the pattern at forward and backward endfire. By properly arranging the radiating elements with a small separation, the higher order spatial harmonics are suppressed. Fed by an air-substrate microstrip line working on the non-dispersion transverse electromagnetic (TEM) mode, the antenna has a moderate phase constant leading to a stable endfire array factor. By integrating the almost unchanged array factor and element pattern, the dual-beam radiation pattern with reduced beam squinting is obtained. To verify the design strategy, a prototype was designed, fabricated, and measured. Over the operating bandwidth from 2.7 to 3.2 GHz, the antenna exhibits a small measured beam squint of 6.8°.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Calibration of Stochastic Radio Propagation Models Using Machine Learning
    • Authors: Ramoni Adeogun;
      Pages: 2538 - 2542
      Abstract: This letter proposes a machine learning-based method for the calibration of stochastic radio propagation models. Model calibration is cast as a regression problem involving mapping of the channel transfer function or impulse response to the model parameters. A multilayer perceptron is trained with summary statistics computed from synthetically generated channel realizations using the model. To calibrate the model, the trained network is used to estimate the model parameters from channel statistics obtained from measurements. The performance of the proposed method is evaluated with propagation graph and Saleh–Valenzuela models using both simulated data and in-room channel measurements. Results show accurate estimation of the parameters of both models.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Compact UWB Uniplanar Four-Port MIMO Antenna Array With Rejecting Band
    • Authors: Ricardo Gómez-Villanueva;Hildeberto Jardón-Aguilar;
      Pages: 2543 - 2547
      Abstract: A compact uniplanar four-port multiple-input–multiple-output (MIMO) antenna array is presented. The antenna covers a small area of 38.3 × 38.3 mm2 and is developed on a single layer of a laminate of $varepsilon _r=4.5$ and width 0.8 mm. The MIMO array has an impedance bandwidth of 3–13.2 GHz with an average gain of 4.1 dBi and efficiency between 72% and 97%. The main decoupling technique used in this MIMO array was polarization diversity. Additionally, a set of slits was etched in the ground plane to reduce the ECC to 0.02 and less in the operative bandwidth. A distinctive characteristic of the proposed array is that it is uniplanar and can be easily implemented in mobile terminals where the antennas are printed in only one face of a dielectric surface that is not completely flat.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • An Ultrawideband Capsule Antenna for Biomedical Applications
    • Authors: Jiangli Shang;Ying Yu;
      Pages: 2548 - 2551
      Abstract: This letter presents a symmetrical dual-loop antenna with ultrawideband performance and operating in the Industrial Scientific, and Medical (ISM, 2.4–2.4835 GHz) band for use in wireless endoscopy applications. The antenna is composed of two identical loops located symmetrically around the center, a feeding patch at the center of the feeding loop, and a parasitic patch connected to another loop. A simulated ultrawideband of 143%, ranging from 1.11 to 6.03 GHz, can be achieved in the ISM band by adding two rectangular patches at the center of these two loops and rotating the feeding direction by 90°. Finally, the proposed antenna is measured in pork, and a measurement bandwidth of 124% is obtained.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • A Miniature High-Sensitivity Active Electric Field Probe for Near-Field
    • Authors: Zheng Min;Zhaowen Yan;Wei Liu;Jianwei Wang;Donglin Su;Xin Yan;
      Pages: 2552 - 2556
      Abstract: A noncontact active electric field probe with miniature size and high sensitivity is designed for the noise location in electronic systems from 9 kHz to 1 GHz. This probe is fabricated in a multilayer printed circuit board (PCB) (dielectric constant of 4.2 and loss tangent of 0.02). The minimum width of the probe is 4 mm, and the length is 48 mm, which allows it to be used in compact and complex space like the PCB and the integrated circuit. The dual-stage amplifier circuit and the door-shaped structure are applied to the probe design, which improves the transfer gain of the probe 40–50 dB higher than that of an equivalently sized passive electric field probe. The spatial resolution is 0.6 mm, while the height of the probe tip above the device under the test is 0.3 mm. The proposed probe is verified with three-dimensional electromagnetic simulation and near-field measurement.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Design Method for Capacity Enhancement of Pattern-Reconfigurable MIMO
           Vehicular Antennas
    • Authors: Jerzy Kowalewski;Joerg Eisenbeis;Magnus Tingulstad;Zsolt Kollar;Thomas Zwick;
      Pages: 2557 - 2561
      Abstract: This letter presents a novel design and evaluation procedure for capacity-enhancing multiple-input–multiple-output (MIMO) antenna systems for mobile communication. Based on channel simulations, optimized patterns are defined prior to an antenna design. A multiple-antenna system is proposed, which switches between patterns covering desired directions. This antenna system is then evaluated in an urban environment at 2.49 GHz based on 2 × 2 MIMO channel simulation and measurement results. An improvement of the channel capacity exceeding 1 b/s/Hz compared to an omnidirectional antenna system is confirmed by both simulation and measurement.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Time-Reversal Processing for Downlink-Limited Passive UHF RFID in Pulsed
           Wave Mode
    • Authors: Mingshan Zhang;Chengran Fang;Pavlos Doanis;Julien Huillery;Arnaud Breard;Yvan Duroc;
      Pages: 2562 - 2566
      Abstract: This letter provides experimental evidence that, in a complex environment, a time-reversal processing of electromagnetic waves can increase the energy efficiency of the reader to tag communication and, hence, can increase the activation range of a passive ultrahigh frequency (UHF) radio frequency identification (RFID) system. A first experiment performed in a free-space environment shows that in addition to the classical continuous wave (CW) mode, a type AD222 passive UHF RFID tag can successfully operate in a pulsed wave (PW) mode using pulses with half-width 5 ns and period 35 ns. In a second experiment performed in a complex multipath environment, it is shown that the energy efficiency of the RFID system in the PW mode can be increased by applying a time-reversal (TR) processing strategy. Furthermore, it is shown that both PW and TR strategies involve less energy to activate the tag than the classical CW mode does. As a consequence, given a fixed amount of energy, TR processing can increase the activation range of the RFID system.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Antenna Correlation Under Geometry-Based Stochastic Channel Models
    • Authors: Yilin Ji;Wei Fan;Pekka Kyösti;Jinxing Li;Gert Frølund Pedersen;
      Pages: 2567 - 2571
      Abstract: Antenna correlation is an important measure for designing multiple-input–multiple-output (MIMO) antenna systems. A lower antenna correlation indicates a better MIMO performance that can be achieved with the underlying antenna systems. In the antenna design community, it is very common to evaluate the antenna correlation with isotropic or nonisotropic (e.g., Gaussian-distributed) angular power spectrum (APS) as baselines. On the other hand, antenna correlation can also be evaluated via channel transfer function (CTF) under the given propagation channel, e.g., drawn from the bidirectional geometry-based stochastic channel model. In this letter, the analytic forms for the antenna correlation based on the APS and the CTF are derived, respectively, with their similarities and differences explained. Moreover, a numerical example is also given with a standard channel model to support our findings.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Washing Durability of PDMS-Conductive Fabric Composite: Realizing Washable
           UHF RFID Tags
    • Authors: Roy B. V. B. Simorangkir;Duc Le;Toni Björninen;Abu Sadat Md. Sayem;Maxim Zhadobov;Ronan Sauleau;
      Pages: 2572 - 2576
      Abstract: In this letter, we present experimental investigations on washing durability of a polydimethylsiloxane (PDMS)-conductive fabric composite to validate its applicability for the realization of flexible wearable antennas that can withstand multiple washing cycles. For this purpose, we designed an ultrahigh-frequency (UHF) radio frequency identification (RFID) passive tag antenna and fabricated several prototypes using such materials combination. Understanding the challenge of having a robust integration of a lumped electronic component (e.g., RFID IC) on a flexible antenna, a new way to improve the interconnection has also been investigated. The tag prototypes were subjected to recurrent machine-washing tests, and after each washing cycle, their performance was analyzed mainly in terms of the read range. The results reveal that, with a proper treatment on the antenna–IC fixture interconnection, the tag antennas developed with the PDMS–conductive fabric composite can maintain their performance very well, showing a minimum degradation in the read range after 15 cycles of washing.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Liquid-Crystal-Based Fully Dielectric Lateral Wave Beam-Steering Antenna
    • Authors: Henning Tesmer;Roland Reese;Ersin Polat;Matthias Nickel;Rolf Jakoby;Holger Maune;
      Pages: 2577 - 2581
      Abstract: This letter presents a fully dielectric beam-steering lateral antenna operating at the V-band (50 GHZ). The antenna consists of a semicircular Rexolite body with an embedded liquid crystal (LC) cavity. An electrode network is used in order to align the LC molecules such that they form reconfigurable areas of high and low permittivity. The area of high permittivity is used to steer the direction of the beam. Due to the dielectric nature of the antenna, it shows enhanced fabrication simplicity and a weight reduction factor of 21 when compared to previous work. In addition, the bias electrodes may have arbitrary shape and are easily accessible, ensuring a high versatility for future designs. The steering mechanism is nearly frequency-independent, and the antenna is matched throughout the whole frequency range. Beam-steering angles of 17$^circ$ are reported with a gain of 16 dBi and a maximum sidelobe level of $-$7.6 dB.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Holey Metasurface Prism for the Reduction of the Dispersion of Gap
           Waveguide Leaky-Wave Antennas
    • Authors: Nafsika Memeletzoglou;Eva Rajo-Iglesias;
      Pages: 2582 - 2586
      Abstract: Leaky-wave antennas are dispersive, meaning that the direction of maximum radiation is a function of frequency. This behavior, called “beam squinting effect” can be reduced by introducing a dispersive metamaterial prism. In this letter, a holey metasurface prism is combined with a leaky-wave antenna in gap waveguide technology. The dispersion characteristics of the hole unit cell are studied in order to achieve the reduction of the main beam steering aiming to $pm 1^{circ }$ or less variation. A prototype designed at the Ka-band is measured and compared with the simulation results.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Dual-Band Circular Polarizers Based on a Planar Chiral Metamaterial
    • Authors: Rike Jie;Handan Jing;Shiyong Li;Yu Xiao;
      Pages: 2587 - 2591
      Abstract: A novel dual-band chiral metamaterial (CMM) circular polarizer is proposed based on a dual-armed wheel-like structure. The proposed CMM can convert a linearly polarized electromagnetic wave into a circularly polarized (CP) mode. The simulation and measured results show, with good consistency, that the CMM exhibits good CP characteristics, such as a polarization isolation higher than 18 dB and an axial ratio lower than 1 dB. In addition, our studies show that all the resonance frequencies of this CMM structure are independent. Finally, a simple design method is presented and verified by a simulation to change the resonance frequencies of the proposed dual-band CMM circular polarizers.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Three-Dimensional Higher Order PML Based on Alternating Direction Implicit
    • Authors: Pei Yu Wu;Hao Lin Jiang;Yong Jun Xie;Li Qiang Niu;
      Pages: 2592 - 2596
      Abstract: Based on the alternating direction implicit finite-difference time-domain (ADI-FDTD) algorithm, a higher order perfectly matched layer (HO-PML) is proposed to solve the problems in a three-dimensional computational domain. The proposed scheme can not only take advantage of the HO-PML for improving the absorbing performance but also has the advantage of the ADI-FDTD algorithm in terms of the unconditional stability. A dielectric resonator antenna example is carried out to validate its effectiveness. The results show that the Courant–Friedrich–Levy limit can be eliminated and the absorbing performance can be further enhanced.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • A Dual-Passband Frequency Selective Surface for 5G Communication
    • Authors: Yi Li;Peng Ren;Zheng Xiang;
      Pages: 2597 - 2601
      Abstract: In this letter, a new frequency selective surface is proposed, which is mainly applied to 5G communication. The equivalent circuit method is used to provide assistance for structural design. This structure can generate dual-frequency passbands and achieve double resonant frequencies 28.1 and 39.5 GHz. It acquires large enough bandwidths to cover 27.5–28.35 and 38.6–40 GHz, which are bands of 5G communication. In addition, this structure is a multi-layer structure composed of one metallic layer and two dielectric layers, and its unit size is 0.56λ × 0.56λ, where λ is the wavelength corresponding to the first resonant frequency. Simulated results show that this structure has excellent filtering properties with respect to polarization stability as well as angular stability. Finally, the prototype of this structure is fabricated. The measured results and simulated results have consistent filtering characteristics within the tolerance of error.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Wideband Microwave Absorber With Dynamically Tunable Absorption Based on
           Graphene and Random Metasurface
    • Authors: Bei-Bei Xing;Zhen-Guo Liu;Wei-Bing Lu;Hao Chen;Qing-Dong Zhang;
      Pages: 2602 - 2606
      Abstract: A wideband microwave absorber with dynamically tunable absorption is proposed in this letter. It consists of a few layers of large-area graphene and a layer of random metasurface. Through the superimposition of a few layers of graphene, the tunable range of graphene sheet resistance is lowered to 80–380 Ω/sq, which is more suitable as the resistance film of broadband microwave absorber, because it is easier to match the impedance of free space. In addition, by choosing 12 proper elements of metasurface and distributing them randomly, more resonance frequencies and phase responses can be achieved, thus improving the bandwidth of the microwave absorber and reducing its profile simultaneously. By tuning the sheet resistance of graphene via bias voltage, the absorbance of proposed absorber can be tuned from 80% to 50% in a wide bandwidth from 5 to 31 GHz. The prototype of proposed absorber is fabricated and measured. The reasonable agreement between the simulated and measured results verifies the accuracy of our approach.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Suppression of Antenna Backscatter on a Nanosat Using a Resistively Loaded
           FSS Absorber
    • Authors: Gabriel G. Machado;Robert Cahill;Vincent Fusco;Gareth A. Conway;
      Pages: 2607 - 2611
      Abstract: A very thin microwave absorber that can be integrated into the outermost layer of thermal blankets is proposed as a means to electromagnetically decouple payload antennas from spacecraft platforms. The effectiveness of this concept is evaluated for a critical test case where a linearly polarized dipole antenna working at 10 GHz is placed at three different distances above the surface of a $text{10 cm}$ Nanosat mock-up. This scenario is chosen as the dipole will radiate into both half spaces and any reflections from the vehicle onto which it is mounted will significantly affect its behavior. A resistively loaded frequency selective surface (FSS) absorber is employed to supress the energy contained in the antenna backlobes, and it is shown that the installed performance for all three geometries closely resembles the beam shape of the antenna in isolation. Experimental results have been obtained for one arrangement to confirm that the directive gain is increased by 18 dB in the boresight direction. The FSS absorber is composed of an array of resistively loaded hexagonal patches that are patterned on a 1.12 mm ($lambda /25$) thick foil-backed polyethylene terephthalate sheet to replicate the physical construction of commercially available space blankets.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • A Simple-Topology Compact Broadband Circularly Polarized Antenna With
           Unidirectional Radiation Pattern
    • Authors: Ubaid Ullah;Slawomir Koziel;Ismail Ben Mabrouk;
      Pages: 2612 - 2616
      Abstract: In this letter, a geometrically simple, reflector-backed single-point-fed circularly polarized (CP) antenna with unidirectional radiation pattern is presented. The structure comprises a simple coplanar waveguide feeding circuit with an open slot etched on one side of the coplanar ground. The enhanced CP bandwidth is obtained by combining the loop mode, the slot mode, and the asymmetrical configuration of the coplanar ground planes along the feedline. All parameters are optimized at the full-wave level of description for the best impedance and axial-ratio (AR) bandwidth. The antenna footprint is only 0.35λo × 0.39λo at the lowest CP operating frequency of 3.1 GHz. The measurement results indicate 82% impedance bandwidth (from 3 to 7.2 GHz) and 80% AR bandwidth (from 3.1 to 7.2 GHz). A unidirectional right-hand circular polarization radiation pattern in the +z-direction is also achieved by adding a reflector. The peak realized gain of the antenna is 6.7 dBic, and the peak radiation efficiency is 98%.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • L/S Multiband Frequency-Reconfigurable Antenna for Satellite Applications
    • Authors: Mingyu Sun;Zhe Zhang;Fan Zhang;Aixin Chen;
      Pages: 2617 - 2621
      Abstract: A novel multiband frequency-reconfigurable antenna is presented. The designed antenna can realize L-band single-frequency operation and S-band dual-frequency operation through electronic tuning. Annular ring and sawtooth patches are used as radiators for L/S-band operation and are excited by a broadband reconfigurable orthogonal network through the coupling of a T-shaped slot and a ring slot in the ground plane, respectively. By changing the bias of the p-i-n diodes loaded on the feed network, the operating frequency can be switched between the navigation state and the satellite link receiving state. A high tuning frequency ratio (1.64:1) is obtained. The simulated and measured results show good agreement. Good impedance matching (VSWR $< $ 1.3) and circular polarization characteristics (AR $< $ 3) are obtained in all three operating bands. Achievement of a highly reconfigurable frequency ratio of a circularly polarized antenna provides solutions for multifunction CP antenna aperture sharing.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Axial Ratio Enhancement of a Single-Layer Microstrip Reflectarray
    • Authors: Roger Lorenzoni Farias;Custódio Peixeiro;Marcos V. T. Heckler;Edson R. Schlosser;
      Pages: 2622 - 2626
      Abstract: This letter presents a new approach for the enhancement of the axial ratio (AR) of a single-layer circularly polarized reflectarray antenna based on a circular microstrip patch with phase delay-line stubs unit cell. The AR improvement is achieved by inserting insets around the two stubs, changing the orientation of one of them and using a mirror symmetry arrangement. Two prototypes have been designed, fabricated, and tested to proof the proposed concept in K-band. A good agreement has been obtained between numerical simulations and experimental results. The measured results confirm a remarkable AR improvement with values below 1 dB and 3 dB gain and AR bandwidths larger than 23.7%.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Drone-Based Forest Propagation Measurements for Ground-to-Air EMI
    • Authors: Jerry R. Hampton;Steve Yao;Trevor Kroeger;Candace Carducci;Corry Murphy;
      Pages: 2627 - 2631
      Abstract: This letter describes measurements of path loss caused by a leafless, mid-Atlantic deciduous forest on ground-to-air (G-A) paths using a drone-based measurement system. The focus of these measurements is on slant paths with low elevation angles (
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Dual-Band Frequency Selective Surface on Aperture-Coupled Patch Resonators
           With Different Polarization Rotation
    • Authors: Jin-Ming Xie;Bo Li;Yun-Peng Lyu;Lei Zhu;
      Pages: 2632 - 2636
      Abstract: In this letter, a dual-band frequency selective surface (FSS) based on aperture-coupled patch resonators is proposed to achieve different angles of polarization rotation, that is, 90° and 0°. The dual-band response is achieved by periodically arranging two independent subelements consisting of back-to-back patch resonators with coupling apertures etched on the middle metallic layer. Herein, the first passband is realized by the crossed patch resonators with a pair of rectangular apertures etched beneath the edges of the crossed patches. It can produce 180° phase difference between the two orthogonal components of a linearly polarized incident wave oriented to the diagonal of the FSS elements, thus rotating the incident polarization to its orthogonal one in this first passband. The second passband is caused by the square patch resonators with crossed apertures etched beneath the center of the square patches, thereby maintaining the incident polarization unchanged in this second passband. The operation principle is, then, extensively analyzed and discussed. To validate the design concept, the proposed FSS is designed, fabricated, and measured. A good agreement between the measured and simulated results is achieved to reveal the attractive dual-band and dual-polarization features of the proposed FSS.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Highly Efficient 2.4 and 5.8 GHz Dual-Band Rectenna for Energy Harvesting
    • Authors: Kapil Bhatt;Sandeep Kumar;Pramod Kumar;Chandra Charu Tripathi;
      Pages: 2637 - 2641
      Abstract: In this letter, highly efficient dual-band rectenna at 2.4 and 5.8 GHz for energy harvesting is presented. A new sickle-shaped antenna is designed to operate at both frequencies. Rectenna shows the maximum RF–DC conversion efficiency of 63% and 54.8% at 2.4 and 5.8 GHz, respectively. The impact of matching network and output filter on RF–DC conversion efficiency at both frequencies is analyzed. The output dc voltage of 3 and 2.6 V is measured for 2.4 and 5.8 GHz correspondingly at a 600 Ω load resistance. The rectenna can be utilized for various low-power applications.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Design and Evaluation of Planar Bifilar Helical Antennas for Radio
           Frequency Identification Tags
    • Authors: Weikang Chen;Zhenyi Niu;Mengyuan Li;Zhuo Li;Qian Xu;Changqing Gu;
      Pages: 2642 - 2646
      Abstract: In this letter, planar bifilar helical antennas with varied turns for ultrahigh-frequency radio frequency identification (RFID) tags are proposed. The bifilar helix, formed using printed strips with straight-edge connections implemented by plated via-holes, is employed to match the complex impedance of the chip. The structures of the two-turn, one-turn, half-turn, and quarter-turn helical antennas are simulated and optimized. The simulation results show that the gain of the antenna is improved as the turn number increases. The gain of the quarter-turn helical antenna is 3 dB lower than that of the two-turn helical antenna, but the size of the quarter-turn helical antenna is only 3.1% of that of the two-turn helical antenna. Thereafter, the impedance, efficiency, and mutual coupling of these fabricated antennas are investigated in a reverberation chamber. The simulated and measured results show that the coupling between two stacked quarter-turn helical antennas is 15 dB lower than that of the commercial tags Alien 9662 in the operating frequency band. The proposed tags can achieve a maximum read range of over 40 cm in free space and 36 cm in dense environment. The radiation efficiencies of the tags are more than 55% at 920–925 MHz (China RFID band).
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Compact Postwall Slotline-Based Stepped Impedance Resonator Decoupling
           Structure for Isolation Enhancement of Patch Antenna Array
    • Authors: Cheng Lu;Qiuyi Zhang;Hongye Qi;Shunli Li;Hongxin Zhao;Xiaoxing Yin;
      Pages: 2647 - 2651
      Abstract: A compact decoupling structure, implemented by the postwall slotline (PWS)-based stepped impedance resonator (SIR), is proposed for enhancing the isolation between patch antennas. A pair of SIRs is placed between microstrip antennas to cut off the coupling path, which enhances the decoupling performance greatly at resonance frequency. Meanwhile, designed with a combination of conventional slotline and the PWS, the decoupling structure has a compact profile and, thus, is suitable for miniaturized element space. A two-element patch array is designed and fabricated to verify the decoupling effectiveness of the proposed structure, by providing simulated and measured results. Measured realized gain of the antenna with proposed structure is about 5.1 dBi. High isolation of 30.4 dB at 5.7 GHz is achieved, and the edge-to-edge distance is 0.059λ0 with the decoupling structure. Moreover, with the decrease of element distance, isolation improvement will be significantly enhanced. The compact size and isolation performance show the potential of the structure to be applied in antennas arrays including multi-input–multi-output systems and adaptive arrays.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Compact GNSS Metasurface-Inspired Cavity Antennas
    • Authors: Laura Garcia-Gamez;Loïc Bernard;Sylvain Collardey;Hrvoje Covic;Ronan Sauleau;Kourosh Mahdjoubi;Patrick Potier;Philippe Pouliguen;
      Pages: 2652 - 2656
      Abstract: This letter presents an innovative circularly polarized compact cavity antenna based on metasurfaces; the proposed design is explained starting from a linearly polarized antenna based on similar concepts. The main objective is to cover three different GNSS systems, namely Galileo E1, GLONASS G1, and GPS L1, with a single antenna embedded in a metallic cavity. The aperture dimension is set to 0.26λ0 × 0.26λ0, with a central frequency of 1578 MHz. Loading the aperture with a metasurface allows an efficient radiation within such a small aperture size. Our experimental results are in a very good agreement with the simulations, with an axial ratio lower than 2 dB between 1540 and 1655 MHz.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Compact Dual-Band Dual-Mode Antenna With Omni-/Unidirectional
           Radiation Characteristics
    • Authors: Chun-Xu Mao;Douglas H. Werner;Yao Zhang;Xiu-Yin Zhang;
      Pages: 2657 - 2660
      Abstract: A novel dual-band dual-mode antenna that operates at 2.45/5.8 GHz is proposed in this letter. The antenna exhibits linearly polarized omnidirectional radiation in the low band, and circularly polarized broadside radiation in the high band. To improve the 3 dB axial-ratio (AR) bandwidth, both truncated patches and a sequential rotation technique are combined together in the antenna design. The omnidirectional radiation in the low band is achieved by exciting four open-ended slots etched in the ground plane for the first time. The four slots form a magnetic-dipole-like current distribution along the edge of the ground plane, resulting in omnidirectional radiation. The low- and high-band operations are seamlessly integrated into a common design, sharing the same structure. This work provides a novel approach for improving the versatility of a radio frequency front-end subsystem without increasing footprint. The proposed antenna is prototyped and measured, showing good results in terms of impedance/AR bandwidths, isolation, radiation, and polarization.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Nonreciprocal Yagi–Uda Filtering Antennas
    • Authors: Jiawei Zang;Xuetian Wang;Alejandro Alvarez-Melcon;Juan Sebastian Gomez-Diaz;
      Pages: 2661 - 2665
      Abstract: This letter proposes a novel and compact nonreciprocal filtering antenna based on temporal modulation. The device is composed of a third-order filtering section integrated into a Yagi–Uda planar printed antenna. Strong nonreciprocity in transmission and reception is achieved at the same operation frequency by time-modulating the resonators of the filtering section. These resonators are implemented as quarter-wavelength microstrip lines terminated with varactors located on the ground plane. Such plane is also employed as a reflector for the Yagi–Uda antenna and to host the coplanar waveguides that feed low-frequency signals to the varactors, thus leading to a very compact design. A prototype is manufactured and successfully tested at 2.4 GHz, showing isolations greater than 20 dB between transmission and reception modes in both E- and H-planes for all directions in space and a gain drop of only 3.5 dB compared to a reference antenna. The proposed devices can easily be integrated with other electronic circuits and may find exciting applications in communication, radar, and sensing systems.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Continuous Beam Steering For Phaseless Direction-of-Arrival Estimations
    • Authors: Alessandro Cidronali;Giovanni Collodi;Matteo Lucarelli;Stefano Maddio;Marco Passafiume;Giuseppe Pelosi;
      Pages: 2666 - 2670
      Abstract: This letter presents a system capable of continuous beam steering for direction-of-arrival (DoA) estimation operating at 2.45 GHz, based on the use of a digitally controlled beam-forming network and exploiting a bimodal circularly polarized patch antenna. The network is composed by a digitally controlled attenuator, a phase shifter, and a Wilkinson power divider. The specific achieved beam set constitutes the key feature that allows the DoA estimation approach, based on the phaseless magnitude data of the received signals. Experimental validation confirms a DoA estimation error as low as $0.7^circ$ within the range from $-90^circ$ to $+90^circ$, with a standard deviation of $0.6^circ$.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • A Nonredundant Sampling Representation Managing an Offset Mounting of an
           Elongated Antenna in a Spherical Near-Field Facility
    • Authors: Francesco D'Agostino;Flaminio Ferrara;Claudio Gennarelli;Rocco Guerriero;Massimo Migliozzi;
      Pages: 2671 - 2675
      Abstract: An efficient spherical near-field-to-far-field transformation (NFTFFT), which takes into account the offset mounting of an elongated antenna and employs the same nonredundant (NR) amount of near-field (NF) data as in the onset mounting case, is presented. The interest for this NFTFFT is due to the fact that, for practical reasons, a mounting where the antenna and the scan sphere centers coincide is not always possible. In this case, the amount of NF measurements required by the traditional spherical NFTFFT can significantly increase. In the developed NFTFFT, this drawback has been overcome by accurately recovering these NF data from the gathered NR probe voltage samples through a sampling expansion, attained by suitably using the NR sampling representations and assuming the antenna as enclosed in a prolate spheroid. Numerical and experimental results are reported in order to assess the efficacy of the developed technique.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Wideband Circularly Polarized Dual-Mode Vortex Beams Reflectarray Design
           Using Dual-Semi-Split-Loop Elements
    • Authors: Li Yu;Xiuping Li;Zihang Qi;Hua Zhu;Yuhan Huang;Zaid Akram;
      Pages: 2676 - 2680
      Abstract: In this letter, a wideband circularly polarized reflectarray composed of 30 × 30 unit cells is proposed to generate dual-mode vortex beams. The element consists of two back-to-back semi-split-loop structures printed on the FR-4 substrate, an air layer, and a metal ground plane. The two back-to-back semi-split-loop structures provide the multiresonance property, which can effectively increase the bandwidth. A 360° phase range is achieved by changing the spatial orientations of the element. Based on the proposed element and the superposition design method of aperture field, a dual-mode square aperture vortex beams reflectarray is simulated, fabricated, and experimentally demonstrated. The measured results confirm that two vortex beams carrying +1 and –1 mode of orbital angular momentum are successfully generated in a wide range of frequencies from 5 to 8 GHz. The size of the proposed reflectarray is 75 cm × 75 cm, and the measured maximum gain is 22.2 dBic. The measured 1 dB gain bandwidth is 33.3%.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Cavity-Backed Broadband Circularly Polarized Cross-Dipole Antenna
    • Authors: Yao Feng;Jianying Li;Bao Cao;Jie Liu;Guangwei Yang;Du-Juan Wei;
      Pages: 2681 - 2685
      Abstract: This letter presents a broadband circularly polarized (CP) cross-dipole antenna. It consists of crossed dipoles, parasitic elements, a cavity-backed reflector, and a circular ring reflector. The arms of crossed dipoles are divided into two sectors by a slit. The parasitic elements are utilized to significantly enhance the CP bandwidth. A circular ring reflector is adopted to optimize the radiation pattern and improve the gain in high frequency band. The fabricated prototype of the proposed antenna with an overall size of 0.60λ0 × 0.60λ0 × 0.21λ0 (λ0 is the free-space wavelength at the lowest CP operating frequency) yields a measured impedance bandwidth of 98.2% for |S11|
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Dielectric-Loaded Conformal Microstrip Antennas for Versatile In-Body
    • Authors: Denys Nikolayev;Wout Joseph;Anja Skrivervik;Maxim Zhadobov;Luc Martens;Ronan Sauleau;
      Pages: 2686 - 2690
      Abstract: Wireless implantable bioelectronics and accurate in vivo characterization of path loss require efficient and robust in-body antennas. Loading electric antennas with the effective permittivities higher than that of surrounding tissues are a promising solution. In this letter, proof-of-concept conformal microstrip antennas are proposed. The antennas are optimized for a standard impedance of 50 $Omega$ and operate in all high-water-content tissues. Integral ground plane shields the antenna from inner circuitry. The radiation efficiencies are 0.4%, 2.2%, and 1.2% for the (434, 868, and 1400) MHz designs, respectively, when computed in a $varnothing$100 mm spherical phantom with muscle-equivalent properties. The efficiencies are compared to the fundamental limitations and closely approach them. Specific absorption rates are evaluated, and the corresponding maximum input power levels are established. Prototypes are fabricated and characterized to validate the design.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Power-Gain Pattern Synthesis of Array Antenna With Dynamic Range Ratio
    • Authors: Shiwen Lei;Haoquan Hu;Pu Tang;Bo Chen;Jing Tian;Wei Yang;Xiangdong Qiu;
      Pages: 2691 - 2695
      Abstract: By directly solving the power-gain pattern synthesis (PGPS) instead of the shaped-beam pattern synthesis (SBPS), the gain of the antenna array can be improved. However, the dynamic range ratio (DRR) of the optimized results for both PGPS and SBPS are uncontrollable, which can heavily increase the cost of a real system. In this letter, the DRR control scheme for the PGPS problem is discussed. The maximum desired DRR is added, yielding a new nonconvex problem to be solved. This nonconvex DRR restriction is approximated as a linear convex restriction condition, which explicitly provides the lower and upper bounds of the array weight. Finally, with the aid of an existing PGPS-algorithm structure, the designed derivative PGPS problem can be solved effectively. The advantage and effectiveness of the proposed algorithm are validated with simulation results.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Polarization-Insensitive Metasurface Lens for Efficient Generation of
           Convergent OAM Beams
    • Authors: Xudong Bai;Fanwei Kong;Jingyi Qian;Yunzhuo Song;Chong He;Xianling Liang;Ronghong Jin;Weiren Zhu;
      Pages: 2696 - 2700
      Abstract: A novel metasurface lens made of polarization-insensitive hexagonal units with honeycomb lattice is provided for generating orbital angular momentum beams. The unit is composed of multilayer capacitive hexagonal patches coupled through middle-layer inductive snowflake wire grids for a stable bandpass response. Due to the isotropy of the hexagonal unit and the honeycomb lattice of the cell arrangement, the proposed metasurfaces are polarization-insensitive, providing stable responses under different angles and polarizations of the incident electromagnetic wave.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Engineering the Eigenspace Structure of Massive MIMO Links Through
           Frequency-Selective Surfaces
    • Authors: Debdeep Sarkar;Said Mikki;Yahia M. M. Antar;
      Pages: 2701 - 2705
      Abstract: We propose an efficient finite-difference time-domain (FDTD) computational paradigm to estimate the channel matrix of generic massive multiple-input–multiple-output (MIMO) systems. Working with a practical scenario with 196 base station (BS) elements and 6 equispaced user-equipment devices, we compute the dominant eigenspace for the uplink channel. The full-wave results are compared to conventional ray-tracing methods, with emphasis laid upon observing and understanding the electromagnetic (EM) impact of interelement mutual coupling and spherical wavefront illumination on the wireless MIMO channel properties. In particular, we investigate EM manipulation of massive MIMO channel structures by utilizing, especially, engineered wire-grid frequency-selective surfaces placed in the vicinity of the BS massive MIMO array. Using the in-house FDTD code, we demonstrate the capability of such passive structures to redistribute the illumination Poynting vector magnitude over the BS array aperture, as well as modifying the dominant eigenspace at certain design frequencies. This letter demonstrates the advantage of the synergy between rigorous EM analysis and stochastic communication theories and techniques, with expected applications in emerging wireless technologies (5G and beyond).
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Design of Wideband Implantable Antenna for Wireless Capsule Endoscope
    • Authors: Wenjie Cui;Ruipeng Liu;Lu Wang;Mengjun Wang;Hongxing Zheng;Erping Li;
      Pages: 2706 - 2710
      Abstract: In order to adapt to the applications of the wireless capsule endoscope (WCE) system, a wideband implantable antenna is designed. We engrave some slots on both the radiator and the ground plane to miniaturize the size and expand the impedance bandwidth of the antenna. The capacitance loading technique is used to improve the impedance match. The influence of different organs such as the stomach, small intestine, and colon is discussed when the antenna is embedded in the WCE system. Compared to other implantable antennas with similar performance, impedance bandwidth, radiation pattern, and specific absorption rate in one-layer skin phantom model, this design has the best performance. Finally, experiments are carried out on a chicken breast slab to validate our design. Results are shown the proposed antenna available.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Wideband Millimeter-Wave Dielectric Resonator Antenna With Gain
    • Authors: Yazan Al-Alem;Ahmed A. Kishk;
      Pages: 2711 - 2715
      Abstract: A novel technique is proposed to enhance the gain of a rectangular dielectric resonator antenna over a wideband range of frequencies. The proposed antenna structure has a relative bandwidth of 27.5% in the 60 GHz band (16 GHz of absolute bandwidth), and a peak realized gain of 12.6 dBi. The simulated antenna radiation efficiency goes up to 96%. A printed electromagnetic bandgap technology has been used to feed the antenna and eliminate any parasitic radiation from the feedline.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • A 2.4 GHz Rectenna Based on a Solar Cell Antenna Array
    • Authors: Eduardo Vicente Valdés Cambero;Humberto Pereira da Paz;Vinicius Santana da Silva;Humberto Xavier de Araújo;Ivan Roberto Santana Casella;Carlos Eduardo Capovilla;
      Pages: 2716 - 2720
      Abstract: Combined solar and radio frequency (RF) harvesting systems are drawing attention by offering self-powered ability to low-power devices, an essential aspect to the success of the Internet of Things. One of the main challenges of these harvesting systems is to improve rectennas efficiency by optimizing the individual energy collection and conversion capacity of each source. To overcome this issue, this letter presents a novel 2.4-GHz rectenna structure for solar and radio frequency energy harvesting applications based on a coplanar antenna array integrated with multicrystalline solar cells, whose aluminum rear terminals are used as radiators for the antenna array. The results obtained by simulations and measurements show that it is possible to collect energy from two different types of sources in a complementary manner, using the rectenna design proposed, making it possible to feed low-power devices remotely.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • A K-Band 3-D Printed Focal-Shifted Two-Dimensional Beam-Scanning Lens
           Antenna With Nonuniform Feed
    • Authors: Bing Zhang;Li Wu;Yanping Zhou;Yang Yang;Huacheng Zhu;Fei Cheng;Qian Chen;Kama Huang;
      Pages: 2721 - 2725
      Abstract: A K-band (18–26.5 GHz) two-dimensional (2-D) beam scanning antenna is proposed. The hyperbolic lens is fed by an array of focal-shifted horns with nonuniform aperture. The feed at the focal point of the lens generates the boresight vertical beam, while the off-focal feeds are responsible for tilted beams. The nonuniform horn aperture helps to mitigate the gain decrement from the lens aperture tapering. It is fabricated taking full advantage of dielectric and metallic 3-D printing technologies. The lens is printed by stereolithography apparatus (SLA) in resin. The feed horn array is printed by selective laser melting (SLM). Process-wise, it features low cost, short turnaround time, and the capability to implement complex geometries versus traditional computer numerical control machining and mold casting. Simulation and measurement indicate that the antenna features desirable matching below −15 dB and mutual coupling between adjacent port below −25 dB. The gain is above 23 dBi across the K-band. Multiple beams at ±32°, ±12°, and 0° are observed on E- and H-planes. The proposed design can either function as multibeam antenna or a beam-scanning antenna together with switches. It is a capable candidate for applications such as multiple target tracking and wide region monitoring.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Design of a Compact 3-D Metal Printed Ka-band Waveguide Polarizer
    • Authors: Ila Agnihotri;Satish K. Sharma;
      Pages: 2726 - 2730
      Abstract: This letter presents design, development, and characterization of compact wideband three-dimensional (3-D) printed circular waveguide-based polarizer operating in Ka-band (28–34 GHz). The polarizer structure is investigated using fundamental and higher-order modes, based on which a simplified equivalent structure is derived, giving physical insight into its mechanism of operation. The design consists of a pair of radially opposite grooves inside a circular waveguide and excited using a coaxial probe, which makes the design simple and highly compact as compared to other conventional circular polarizers. The design is compared with other existing waveguide-based polarizers in terms of electrical and physical parameters. Fabrication is done using high-resolution direct metal aluminum 3-D metal printing. The measured axial ratio is better than 3 dB over the frequency band. The design simplicity makes it attractive for application in millimeter-wave frequencies and beyond.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Earth-Effect Emulation Using Periodic Structures in Scaled-Model
           Characterization of HF Antennas
    • Authors: Kai Ren;Mohammad Ranjbar Nikkhah;Nader Behdad;
      Pages: 2731 - 2735
      Abstract: We present a technique for emulating the impact of the presence of earth on the responses of high-frequency (HF) antennas characterized using scaled-model measurements. Scaled-model measurements are routinely used to characterize the responses of HF antennas, particularly those mounted on physically large platforms. The presence of the ground in the vicinity of such antennas and its electrical parameters can significantly impact the antenna response. However, this impact is not usually taken into account in scaled-model measurements. In this letter, we demonstrate that the earth impact in such scaled-model measurements can be emulated by using a lossy periodic structure, with subwavelength unit-cell dimensions, designed to emulate the electrical properties of the ground at the scaled frequency of operation. The efficacy of this approach is demonstrated using a design example for a platform-based HF antenna operating in the vicinity of wet earth. A scaled-model prototype of the antenna and the ground-emulating periodic structure are fabricated and experimentally characterized. Measurement and simulation results demonstrate a good agreement and verify the capability of using this approach to perform more accurate, scaled-model measurement of HF antennas.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Holographic Design of Beam-Switchable Leaky-Wave Antenna
    • Authors: Huan-Huan Lv;Qiu-Lin Huang;Jin-Lin Liu;Jian-Qiang Hou;Xiao-Wei Shi;
      Pages: 2736 - 2740
      Abstract: A holographic design of beam-switchable leaky-wave antenna (LWA) is presented. The proposed design consists of a holographic impedance modulated surface (HIMS) and control circuit. In this design, the HIMS, which carries impedance characteristics of four beams, is obtained by using a modified modulation method in the same aperture. Thus, the proposed HIMS can generate four switchable beams at a fixed frequency when it is excited by different reference waves. By controlling p-i-n diodes inserted along the feedline, four working states can be obtained. The proposed LWA is fabricated and measured. Four switchable beams with pitch angles of θ1 = θ2 = −30°, θ3 = θ4 = 30° and azimuth angles of ϕ1 = 0°, ϕ2 = 90°, ϕ3 = 180°, and ϕ4 = 270° are obtained at 18 GHz. The measured peak gain of each beam is better than 17.2 dBi.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Ultrawideband Antipodal Tapered Slot Antenna With Gradient Refractive
           Index Metamaterial Lens
    • Authors: Zhengwei Yang;Linyan Guo;Changli Yao;Qisheng Zhang;Ziyu Xu;Minjie Guo;Ziye Wang;
      Pages: 2741 - 2745
      Abstract: This letter proposes an ultrawideband and high-gain antipodal tapered slot antenna (ATSA) with a gradient refractive index (GRIN) lens. The GRIN lens consisting six metamaterial lenses is placed in the maximum radiation direction of the ATSA to greatly enhance its radiation capability. We found that the proposed GRIN lens antenna has a wide impedance bandwidth of 175.7% (0.84–13 GHz) and −3 dB gain bandwidth of 65.8% (5.86–11.6 GHz). Its gain is averagely increased by 4.81 dB in the whole operating band, and the maximum gain reaches 20.55 dBi at 9.5 GHz. The simulation and measured results demonstrate that the designed GRIN lens antenna has an excellent performance and is suitable for short-pulse ground penetrating radar systems.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • A Design of Wideband Circularly Polarized Antenna With Stable Phase Center
           Over the Whole GNSS Bands
    • Authors: Hongliang Zhang;Yuanyue Guo;Gang Wang;
      Pages: 2746 - 2750
      Abstract: In this letter, a simple crossed-dipole antenna with four parasitic plates is designed to realize a stable phase center. Owing to the high symmetry of crossed dipole, its phase center within a narrow solid region can remain stable. By adding parasitic plates rotationally on the reflector, beamwidth of stable phase center is widened. Both simulation and measurement of the designed antenna yield a –10 dB impedance bandwidth of 63.2% and a 3 dB axial-ratio bandwidth of 52.4%, covering all the global navigation satellite system (GNSS) bands. For each GNSS band, a phase center variation is retained below 3° above the 10° elevation. Over the whole GNSS bands, phase center deviation with frequency is retained below 1.1 mm.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Free-Space-Impedance-Matched Composite Dielectric Metamaterial With High
           Refractive Index
    • Authors: Quang M. Nguyen;Theodore K. Anthony;Amir I. Zaghloul;
      Pages: 2751 - 2755
      Abstract: In this letter, we present an all-dieletric metamaterial (ADM) design to achieve both free-space impedance matching and high refractive index in the X-band. This design is formed by two different-size of dieletric resonator cubes, which are made of strontium titanate, SrTiO3, with high permittivity and low loss. The Mie theory is used as theoretical framework to design high permittivity and high permeability, simultaneously. By scaling the size and lattice constant of the individual units, the first magnetic resonance of one cube (generating high permeability) and the first electric resonance of the other cube (generating high permittivity) can be colocated in order to achieve the free-space impedance matching. The S-parameters and the constitutive parameters are used to demonstrate that the composite cube/cube design has a transmission window with a high refractive index. Experimental measurements are carried out to verify the design concept. All-dieletric metamaterial can be presented as an alternative way to achieve the reflection-less surface, referred to as a Huygens’ surface, and create a high index of refraction at the same time.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Fully 3-D-Printed Frequency-Scanning Slotted Waveguide Array With Wideband
    • Authors: Kunchen Zhao;Jordan A. Ramsey;Nima Ghalichechian;
      Pages: 2756 - 2760
      Abstract: We report the design, fabrication, and measurement results of a fully three-dimensional (3-D) printed frequency-scanning slotted waveguide array (SWA). The antenna system is composed of an 18 × 4 nonresonant (traveling wave) array operating at 12–18 GHz (Ku-band), a wideband 1 × 4 power divider, and four 50 Ω matched loads all fabricated using a 3-D printer and wet metallization steps. The antenna system is designed to be impedance-matched with S11 less than −10 dB across the entire band. Inductive walls are added to the power divider to improve the impedance matching of closely packed waveguides. Complex yet smooth waveguides are fabricated using the PolyJet technology. Conformal in-house metallization processes consisting of nickel electroless plating and copper electroplating are established. Measurement results show beam-scanning ranges from −17° at 12 GHz to +15° at 18 GHz. The maximum measured gain is 21.4 dBi with sidelobe level of −13.4 dB at 15.8 GHz and scanning angle of 7°. Furthermore, the array maintains minimum gain of 10 dBi for most of the band ranging from 13.4 to 17.8 GHz. Our measurement results are in an agreement with the simulations. This letter demonstrates a scanning array, together with a wideband power divider, and termination loads all fabricated using a 3-D printing technology.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Simple Beam Scanning SIW Cavity-Backed Slot Antenna Using Postloaded
    • Authors: Yuan Ji;Lei Ge;Jianpeng Wang;Quangang Chen;Wen Wu;
      Pages: 2761 - 2765
      Abstract: A reconfigurable beam-scanning substrate integrated waveguide (SIW) cavity-backed slot antenna (CBSA) is presented. By adopting three transverse radiating slots and inserting four pairs of postloaded varactors, the field distributing in the SIW cavity can be moderately perturbed. To be specific, two pairs of varactors, flanked by the adjacent slots, are placed in the vicinity of the cavity longitudinal centerline; while the other two pairs are symmetrically embedded at two end parts of the bilateral slots. As such, manipulating biasing voltage applied to each pair of varactors independently could offer very fine control of the amplitude and phase of every single-slot element. Accordingly, the main beam direction of the proposed antenna is electronically controlled. A prototype was designed and fabricated to validate the proposed method. Measured results demonstrate the proposed CBSA with a beam scanning from –30° to 41° and a gain varying between 6.4 and 9.2 dBi.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • $mathcal{H}$ -LU-Based+Preconditioner+for+the+FE-BI-MLFMA+for+3-D+Scattering+Problems&rft.title=IEEE+Antennas+and+Wireless+Propagation+Letters&rft.issn=1536-1225&rft.date=2019&rft.volume=18&rft.spage=2766&rft.epage=2770&rft.aulast=Sheng;&rft.aufirst=Ming-Lin&rft.au=Ming-Lin+Yang;Bi-Yi+Wu;Hong-Wei+Gao;Xin-Qing+Sheng;">An Effective $mathcal{H}$ -LU-Based Preconditioner for the FE-BI-MLFMA for
           3-D Scattering Problems
    • Authors: Ming-Lin Yang;Bi-Yi Wu;Hong-Wei Gao;Xin-Qing Sheng;
      Pages: 2766 - 2770
      Abstract: A flexible and efficient Hierarchical LU ($mathcal{H}$-LU)-based preconditioner ($mathcal{H}$-LU-P) is presented for the hybrid finite element-boundary integral (FE-BI) multilevel fast multipole algorithm for solving three-dimensional scattering by inhomogeneous objects. The formulation of FE-BI is first approximated by using locally approximated integral operators for the BI part to construct a finite element method-absorbing boundary condition (FEM-ABC) based preconditioning matrix. Then, the preconditioning matrix equation is solved by the nested dissection accelerated $mathcal{H}$-LU-based fast direct solver. A semi-geometric clustering strategy is proposed to simplify the cluster tree-building procedure in representing the preconditioning matrix in the $mathcal{H}$-matrix form. Numerical results demonstrate that the $mathcal{H}$-LU-P outperforms other alternative preconditioners, based on multifrontal approach. The scattering by a large and complex aircraft model with a radome on its nose section is calculated, showing the capability and efficiency of the preconditioner.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • A Hybrid FETD Algorithm for Electromagnetic Modeling of Fine Structures
    • Authors: Kaihang Fan;Bing Wei;Xinbo He;Yiwen Li;Xiaolong Wei;
      Pages: 2771 - 2775
      Abstract: A novel hybrid finite-element time-domain (FETD) algorithm is proposed to solve electromagnetic modeling with fine structures. This algorithm is based on the unconditionally stable FETD (US-FETD) and the traditional FETD methods. The US-FETD is used in the subdomain containing all fine grids and parts of coarse grids adjacent to the fine grids. The traditional FETD is applied in the other subdomain. A compensation and correction scheme is used to update the fields on the subdomain boundary. The hybrid FETD can make the explicit time marching unconditionally stable with a uniform time step determined by the coarse grids in the entire computational domain. In addition, the unstable modes of the entire system in the hybrid FETD can be effectively obtained by solving the partial solutions of the eigenvalue problem in the US-FETD subdomain. In comparison with the US-FETD in the entire computational domain, the eigenvalue analysis costs less memory and time. Numerical results certify the high efficiency of the hybrid FETD.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • Corrections to “Ultrawideband Anisotropic Glide-Symmetric
    • Authors: Mahsa Ebrahimpouri;Oscar Quevedo-Teruel;
      Pages: 2776 - 2776
      Abstract: Presents corrections to the above named paper.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
  • 2019 List of Reviewers
    • Pages: 2777 - 2784
      Abstract: The publication offers a note of thanks and lists its reviewers.
      PubDate: Dec. 2019
      Issue No: Vol. 18, No. 12 (2019)
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