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  Subjects -> ELECTRONICS (Total: 188 journals)
Showing 1 - 200 of 277 Journals sorted alphabetically
Acta Electronica Malaysia     Open Access  
Advances in Electrical and Electronic Engineering     Open Access   (Followers: 7)
Advances in Electronics     Open Access   (Followers: 90)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 8)
Advances in Power Electronics     Open Access   (Followers: 38)
Advancing Microelectronics     Hybrid Journal  
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (Followers: 335)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 26)
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)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 30)
Bioelectronics in Medicine     Hybrid Journal  
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 20)
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: 293)
ECTI Transactions on Computer and Information Technology (ECTI-CIT)     Open Access  
ECTI Transactions on Electrical Engineering, Electronics, and Communications     Open Access  
Edu Elektrika Journal     Open Access   (Followers: 1)
Electrica     Open Access  
Electronic Design     Partially Free   (Followers: 117)
Electronic Markets     Hybrid Journal   (Followers: 7)
Electronic Materials Letters     Hybrid Journal   (Followers: 4)
Electronics     Open Access   (Followers: 97)
Electronics and Communications in Japan     Hybrid Journal   (Followers: 10)
Electronics For You     Partially Free   (Followers: 100)
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 Materials     Full-text available via subscription   (Followers: 3)
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: 204)
Haptics, IEEE Transactions on     Hybrid Journal   (Followers: 4)
IACR Transactions on Symmetric Cryptology     Open Access  
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 99)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 80)
IEEE Journal of Emerging and Selected Topics in Power Electronics     Hybrid Journal   (Followers: 49)
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: 72)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 71)
IEEE Transactions on Automatic Control     Hybrid Journal   (Followers: 58)
IEEE Transactions on Circuits and Systems for Video Technology     Hybrid Journal   (Followers: 26)
IEEE Transactions on Consumer Electronics     Hybrid Journal   (Followers: 42)
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: 12)
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: 55)
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: 70)
Industrial Technology Research Journal Phranakhon Rajabhat University     Open Access  
Industry Applications, IEEE Transactions on     Hybrid Journal   (Followers: 35)
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: 11)
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: 6)
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: 3)
Journal of Advanced Dielectrics     Open Access   (Followers: 1)
Journal of Artificial Intelligence     Open Access   (Followers: 11)
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: 32)
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: 173)
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: 29)
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: 27)
Nanotechnology Magazine, IEEE     Full-text available via subscription   (Followers: 41)
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: 15)
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: 3)
Recent Advances in Electrical & Electronic Engineering     Hybrid Journal   (Followers: 9)
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: 78)
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  
Universal Journal of Electrical and Electronic Engineering     Open Access   (Followers: 6)
Ural Radio Engineering Journal     Open Access  
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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Journal Cover
IEEE Transactions on Antennas and Propagation
Journal Prestige (SJR): 1.309
Citation Impact (citeScore): 5
Number of Followers: 71  
  Full-text available via subscription Subscription journal
ISSN (Print) 0018-926X
Published by IEEE Homepage  [191 journals]
  • IEEE Transactions on Antennas and Propagation
    • PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • IEEE Transactions on Antennas and Propagation
    • PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Institutional Listings
    • PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Generating Circularly Polarized Vortex Electromagnetic Waves by the
           Conical Conformal Patch Antenna
    • Authors: Fei Shen;Jiangnan Mu;Kai Guo;Zhongyi Guo;
      Pages: 5763 - 5771
      Abstract: The generation of vortex electromagnetic (EM) waves carrying orbital angular momentum (OAM) has attracted more and more attention due to its special characteristics and potential applications. In this paper, the circularly polarized vortex EM waves with different OAMs have been generated at 2.4 GHz by a novel conical conformal patch antenna (CCPA) consisting of a conical substrate, a correspondingly conformed circular-ring metallic patch, and a single-feed point. First, we analyze the radiated field of a standard circular-ring patch, in which a circularly polarized TM $_{nm}$ mode excited by two coaxial feeds can generate the circularly polarized OAM wave with the topological charge of $l = (n - 1$ ). Then, a pair of the slot is added to the CCPA for obtaining a simpler structure with a single feed point. By adjusting the size of the slot and the angle between the slot and the single-feed point, two orthogonal modes with the same amplitude and a relative 90° phase shift can be obtained for generating the circularly polarized vortex wave. In addition, we have also tried to use an additional conical horn outside of the CCPA for enhancing the performance of the antenna. Finally, in order to validate the theoretical results, we have also fabricated and measured the CCPA, from which we can confirm that our design is efficient for generating the vortex waves.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • An Extremely Low-Profile Wideband MIMO Antenna for 5G Smartphones
    • Authors: Da Qing Liu;He Jia Luo;Ming Zhang;Huai Lin Wen;Bin Wang;Jun Wang;
      Pages: 5772 - 5780
      Abstract: A low-profile MIMO antenna is proposed for applications in mobile devices. The antenna is designed by placing multiple inverted-F antennas (IFAs) on an artificial magnetic conductor (AMC) ground. The IFAs excite two distinct modes on the AMC, i.e., the local resonant mode and the TM0 surface-wave mode. By combining the two modes, a fractional bandwidth of 12% is realized with a profile of $0.01lambda _{0}$ , where $lambda _{0}$ is the free-space wavelength at the center frequency. Within the working band, the radiation efficiencies are higher than 50%, the mutual couplings among antennas lower than −10 dB, and envelope correlation coefficients (ECCs) lower than 0.2. To validate the antenna design, a MIMO antenna with eight elements is fabricated and measured. The antenna can work from 3.4 to 3.8 GHz. The total thickness of the antenna is only 0.97 mm, which can be integrated into smartphones as their back-covers without occupying the inner space of the device. The throughput achieved by the antenna in an outdoor environment is also tested using a fifth-generation (5G) MIMO system. The MIMO performance will be discussed and compared with traditional antennas.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • $S$+ /Ka/+$D$+ -Band+Antennas+in+LTCC+With+a+Cylindrical+Radome+for+Triband+Applications&rft.title=IEEE+Transactions+on+Antennas+and+Propagation&rft.issn=0018-926X&;&rft.aufirst=Jiawei&;Min+Tang;Qi+Chen;Yao-Ping+Zhang;Junfa+Mao;">Integration of $S$ /Ka/ $D$ -Band Antennas in LTCC With a Cylindrical
           Radome for Triband Applications
    • Authors: Jiawei Qian;Min Tang;Qi Chen;Yao-Ping Zhang;Junfa Mao;
      Pages: 5781 - 5789
      Abstract: This paper presents the integration of ${S}/textit {Ka}/{D}$ -band antennas in a low-temperature cofired ceramic (LTCC) package. Three types of antennas, microstrip patch, grid array, and step-profiled horn, operating at different bands are compactly assembled in the same substrate. For electromagnetic isolation, a specific layout and extra-shielding structures, such as fences of metallic vias and air cavities, are designed to reduce the unwanted coupling between antennas. In addition to the antennas, a cylindrical radome is introduced closely attached to the surface of the LTCC substrate. Since radome acts as a dielectric superstrate, its influence on radiation performance is also taken into consideration, especially for ${D}$ -band operation, where a ring-shaped cavity is introduced to suppress the detrimental propagation of surface waves inside radome and enhance the gain as a consequence of dielectric loading effect. Measured results agree well with simulation. Proposed triband antennas, working at three frequencies 3, 30.5, and 120 GHz, achieve broadside gains of 6.51, 9.74, and 13.36 dBi with −10 dB fractional impedance bandwidths of 15.3%, 6.1%, and 6.5%, respectively.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Millimeter-Wave Substrate Integrated Gap Waveguide Leaky-Wave Antenna for
           WiGig Applications
    • Authors: Mohammad Reza Rahimi;Nima Bayat-Makou;Ahmed A. Kishk;
      Pages: 5790 - 5800
      Abstract: A new design of an H-polarized leaky-wave antenna (LWA) based on the substrate integrated gap waveguide (SIGW) technology is introduced. The antenna shows good scanning capability from the backward to a near broadside direction (from −36° to −15°) with a peak gain of 17.67 dBi within 1.3 dB variation over 57–64 GHz and a wide impedance bandwidth. A pair of LWAs is parallelly excited through a Y-power divider and terminated with the other end in series providing an additional 3 dB gain compared to the single LWA. Both designs show over 88% radiation efficiency and over 86% total efficiency. The fabricated prototypes of both antennas are made of multi-layered PCB technology. The measurement results show a good agreement with the simulations.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Coupled-Resonator Theory of Isolation in Multi-Mode Antennas
    • Authors: David R. Hendry;Amin M. Abbosh;
      Pages: 5801 - 5811
      Abstract: The literature currently maintains the assumption that mutual coupling is the mechanism that leads to the degradation of isolation between the active ports of antenna arrays. However, this paper shows that a coupled-resonator model with series-coupled mutual coupling breaks down when applied to multi-mode/multi-port antenna arrays and limits the achievable isolation. An improved model based on parallel-coupled modes is presented. This model suggests that poor isolation is more accurately caused by unbalanced antenna modes. Using this model, several novel examples of simple and compact dual- and triple-mode antennas show how to maximize isolation in multi-mode antennas by balancing the modes’ resonant frequencies and radiation bandwidths. For comparison, the mutually coupled assumption limits isolation to around 20 dB in the proposed novel structures, whereas 40–70 dB is possible when parallel-coupled modes are considered. Based on the developed concept, a compact triple-mode two-pole-filtering antenna is fabricated at 3500 MHz with 160 MHz of bandwidth and more than 40 dB of isolation between the antenna ports.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Characterization and Performance of an Ultra-Wideband Wide-Coverage
           Multimode MIMO Antenna
    • Authors: David S. Prinsloo;Andrés Alayón Glazunov;Rob Maaskant;Marianna V. Ivashina;Vitalii Kukush;Petrie Meyer;
      Pages: 5812 - 5823
      Abstract: A new ultra-wideband multimode (MM) antenna design that enables the detection/transmission of two orthogonal field components over a nearly hemispherical coverage area is presented in this paper. It integrates and colocates two perpendicularly oriented bow-tie dipole elements, a short convex monopole and four horizontally oriented tapered slot antenna (TSA) elements (formed by the dipoles) in order to produce four decoupled and complementary gain patterns. The antenna feeding structure includes four single-ended transmission lines supporting the desired set of individual excitation modes. Experimental verification confirms the predicted negligible coupling between the antenna operating modes and orthogonality of the corresponding radiated field patterns. These unique features can be exploited in applications where pattern and polarization diversity are of importance. In this study, we have evaluated the proposed antenna as a MIMO base station antenna and characterized it in two different propagation scenarios. For this example, it has been shown that the utilization of the additional monopole and TSA modes plays an important role in maximizing MIMO efficiency in line-of-sight (LOS) scenarios and at the same time provides additional independent data streams in rich scattering scenarios. In both considered scenarios, the antenna is shown to have a MIMO frequency bandwidth of 85%.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Design and Research of a Broadband High-Gain Low-Profile Antenna
    • Authors: Chengwei Zhao;Xiaoping Li;Chao Sun;He Huang;
      Pages: 5824 - 5832
      Abstract: A broadband high-gain low-profile array antenna with a brick structure is presented in this paper. The array antenna is arranged in a $2 times 4$ configuration, and a printed dipole antenna is taken as the element. Two elements along the E-plane are printed on a substrate as a subarray, and four subarrays along the H-plane are arranged orthogonally to the four-way power divider, meaning that the array is a brick structure. The proposed antenna can provide a relative bandwidth of 40% in the frequency range 1.2–1.8 GHz with return loss (RL) greater than 13 dB, a gain greater than 14 dBi, and a height less than 4/10 of the wavelength of the center frequency. The radiation efficiency of the proposed antenna is between 40% and 80% across the operating bandwidth as well as the horn antenna, and the height is only 1/8 of the horn antenna with the same aperture. Finally, a high-gain low-profile antenna with 17 and 20 dBi is provided, which has the same radiation efficiency as the horn, and this design is verified to be equally applicable to antennas with a higher gain.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Compact Folded-Patch With Orthogonal Tuning Slots for On-Metal Tag Design
    • Authors: Kunalen Thirappa;Eng-Hock Lim;Fwee-Leong Bong;Boon-Kuan Chung;
      Pages: 5833 - 5842
      Abstract: A highly miniaturized semi-flexible tag antenna, with dimensions 23 mm $times ,, 7.5$ mm $times ,, 3.2$ mm ( $0.0702lambda times 0.0229lambda times 0.0098lambda $ ), is designed for tagging small metallic objects. It consists of three patches and two foams which are tactfully folded to form a very compact three-layer structure. Multiple slots are etched on the top and middle patches for increasing the current paths, where the slots on the top patch are made orthogonal to those in the middle one so that the currents on the two patches do not affect each other. This enables the currents on the two patches to be tuned independently without affecting the tag performances. Despite its small size, the proposed tag is able to generate sufficient antenna resistance to match the impedance of the microchip. As a result, it is able to achieve a good conjugate match with a power transmission coefficient of ~1. The tag has a very compact size of $sim lambda $ /14. It can be read from a distance of 5.0 m when tested on a metal surface with reference to a transmitted power of 4 W effective isotropic radiated power. To the best of our knowledge, as compared to most of the contemporary tags, this is the best performing tag antenna in terms of size-ratio (read distance/tag volume).
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Miniaturized Dual Band Antennas for Intra-Oral Tongue Drive System in the
           ISM Bands 433 MHz and 915 MHz: Design, Safety, and Link Budget
    • Authors: Muhammad Zada;Hyoungsuk Yoo;
      Pages: 5843 - 5852
      Abstract: An intraoral tongue drive system (iTDS) is an assistive technology that enables paralyzed people to improve their lifestyle by allowing them to navigate their wheelchairs and access computers using tongue gestures. In this paper, we present two dual-band antennas: a meandered dipole antenna and a meandered planar inverted-F antenna (PIFA). We designed the proposed antennas to operate at industrial, scientific, and medical (ISM) bands 433 and 915 MHz to mitigate the external interference issue, which can severely affect frequency bands. Our proposed antenna footprints are $17.25 times 8 times 0.635$ mm3 and $42times 10 times 0.635$ mm3 for the PIFA and dipole antenna, respectively. Initially, we designed and analyzed the proposed antennas in multilayer mouth models. The performances of the antennas were validated in a realistic human head phantom. We analyzed the performances of the antennas in terms of the reflection coefficient, gain, efficiency, bandwidth, and link budget for wireless communication in four scenarios. Additionally, to address safety concerns, we calculated the specific absorption rates (SARs) for both antennas and found them to be safe according to the IEEE C95.1.2005 guideline. Finally, we measured the reflection coefficient in the more realistic environment of a 26 year-old subject’s mouth. The radiation pattern was measured in a 3-D head model and minced pork muscle, which approximated the open and closed mouth scenarios, respectively. The measurement results were in reasonable agreement with the simulation results.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Analytic Model of a Coax-Fed Planar Cavity-Backed Metasurface Antenna for
           Pattern Synthesis
    • Authors: Insang Yoo;Mohammadreza F. Imani;Laura Pulido-Mancera;Timothy Sleasman;David R. Smith;
      Pages: 5853 - 5866
      Abstract: We present an analytic model of a coax-fed planar cavity-backed metasurface antenna for radiation pattern synthesis. The metasurface antenna consists of a printed cavity loaded with metamaterial elements which is excited by a coaxial connector. Each metamaterial element radiates a portion of the reverberating fields in the cavity, contributing to an overall beam pattern. To synthesize a desired pattern, the elements need to be arranged in an aperture and radiate with proper weights at their locations. The weight of each element is jointly determined by the geometry of the cavity and the metamaterial element’s resonant response. To predict and achieve the required weights, we first provide a full analytic description of the interaction of the cavity and the metamaterial elements. After verifying the analytical model through numerical simulations, we utilize it in an iterative scheme to solve for the metasurface structure that generates a prescribed pattern. Using the outlined procedure, three different antennas are designed, fabricated, and examined in experiments. Excellent agreement between measured and designed patterns is demonstrated, verifying the proposed analysis and synthesis process. Cavity-backed metasurface antennas with either static or dynamically reconfigurable radiation patterns may find application in communications, imaging and sensing.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Circularly Polarized Fabry–Perot Antenna Using a Hybrid Leaky-Wave
    • Authors: Antoine Calleau;María García-Vigueras;Hervé Legay;Ronan Sauleau;Mauro Ettorre;
      Pages: 5867 - 5876
      Abstract: This paper presents the spectral Green’s function (GF) to analyze Fabry–Perot antennas to generate circular polarization (CP). The structure consists of a single cavity created between a partially reflective surface and a high impedance surface, fed by a low directive, linearly polarized source. Elements in the antenna are characterized by tensor impedances. It allows conceiving a circularly polarized antenna supporting a single hybrid leaky-wave mode. Residue analysis is used to demonstrate that a single hybrid leaky-wave mode is sufficient to generate CP. The tool is validated by an antenna design matched over a relative bandwidth of 28.5% with an axial ratio lower than 3 dB.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Isolation Improvement and Beam Manipulation of Dual-Polarized RIS-Halved
           Lens Antennas for Compact Transceiver Systems
    • Authors: Yuanyan Su;Zhi Ning Chen;
      Pages: 5877 - 5884
      Abstract: A pair of mirror-symmetrical half-lens antennas separated by two finite back-to-back reactive impedance surfaces (RISs) is proposed to improve the isolation between the transmitting and receiving high-gain dual-polarized antennas for a compact monostatic transceiver system. By introducing the desired surface wave and reducing the interference between the source and its image, the RIS is able to manipulate the deflected boresight beam and suppress the increased sidelobes for TM-polarized waves, while TE-polarized performance is maintained as in the case where a perfect electrical conductor (PEC) is used. The effects of RIS properties and feeder orientation on antenna isolation and far-field performance are discussed and compared with the PEC cases. To validate this method, two identical ${X}$ -band half plano-convex dielectric lenses with a diameter of 237 mm and a thickness of 154 mm integrated with two 32°-rotated feeders and RISs of $479times258.3$ mm2 with a characteristic impedance of $text{j}189~Omega $ are designed as an example. The measured results show that the isolation of >51 and >36 dB over a 10dB return loss bandwidth of 2 GHz is achieved for TE and TM polarization, respectively. Compared to the PEC case, the boresight beam correction reaches 7.5° and the first sidelobe close to the adjacent antenna even vanishes in TM polarization when using the RIS. A boresight gain of 20 dBi/21 dBi at 10 GHz is realized for TE/TM polarization, respectively. Hence, the proposed method is a good option for radar systems requiring compact high-performance transceivers.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Compact Endfire Coupled-Mode Patch Antenna With Vertical Polarization
    • Authors: Haozhan Tian;Lijun Jiang;Tatsuo Itoh;
      Pages: 5885 - 5891
      Abstract: Coupled-mode patch antenna (CMPA) is able to reform the beam by manipulating the phase of the fringing fields at the edges. In this paper, a method is proposed to realize endfire radiation with vertical polarization based on the concept of CMPA. Besides the phase controlled by the coupling, the asymmetric feeding introduces additional phase shift to one of the radiation slots, which makes the beam pointing to the forward endfire direction within the whole band. The ground of the antenna is truncated to be the same size of the top patch, which eliminates the undesired effect of the ground edge and ensures the symmetric patterns pointing around endfire direction. The size of the antenna itself is only $0.26lambda _{0} times 0.44lambda _{0}$ , where $lambda _{0}$ is the free-space wavelength at the center operating frequency. In order to block the unwanted common mode current outside the feeding coaxial cable, a quarter-wavelength balun is applied in the implementation. The fabricated antenna sample has highly selective two-pole $S_{11}$ response with center frequency of 2.41 GHz and 10 dB fractional bandwidth of 2.5%. The simulated and measured patterns confirm the endfire radiation of the proposed antenna. The measured 3 dB bandwidth of realized gain at forward endfire is 2.5% at center frequency of 2.41 GHz, where the realized gain is 2.8 dBi and the front-to-back (F/B) ratio is 17.1 dB. The proposed endfire antenna with vertical polarization has the advantages of its inexpensive and friendly fabrication, compact and simple configuration, and high selectivity.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Novel Reliable and Practical Decoupling Mechanism for Strongly Coupled
           Antenna Arrays
    • Authors: Soufiane Tebache;Adel Belouchrani;Farid Ghanem;Ali Mansoul;
      Pages: 5892 - 5899
      Abstract: In this paper, a novel antenna decoupling approach is investigated. The introduced concept is based on expelling the currents flowing between the closely spaced antennas through a tapered slot etched on the array ground plane. The method is free from extra-reactive components and transmission lines. Although they are closely spaced and strongly coupled, the technique allows a high improvement in port isolation. A practical implementation of this mechanism is applied to a monopole array of two elements working at 2.45 GHz and closely packed ( $0.069lambda _{0}$ ). The obtained results are very attractive, and a decoupling of about 40 dB is achieved with good impedance matching. Moreover, radiation diversity is obtained with a gain of 1.9 dBi. Furthermore, the decoupled array is integrated in a real receiving system, and the proposed decoupling technique is checked through the array signal processing. Hence, the obtained results confirm the effectiveness of the proposed decoupling mechanism. In addition to its efficient port isolation, the most attractive features of the proposed decoupling technique are simplicity and ease of implementation in compact multiantenna devices.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • The Two-Port Transmission Method With Applications to Microstrip Phased
    • Authors: Enver Adas;Nicolaos G. Alexopoulos;Franco De Flaviis;
      Pages: 5900 - 5907
      Abstract: A novel method is presented to investigate substrate leaky and/or surface wave mode effects within microstrip antenna arrays. The proposed methodology provides accurate modal analysis for the array elements, while including all metallic and different material inclusions, regardless of geometrical shape. Furthermore, the proposed methodology is very general because it accounts for all phenomena and design requirements including arbitrary excitation of the antenna elements in amplitude and phase, the effect of the substrate modes, mutual coupling, and scan blindness. Substrate waves can be studied directly from the same setup with an operating microstrip phased array. One additional significant advantage of this approach is that interelement antenna array spacing can be larger than half a wavelength in the design of phased arrays, thus, overcoming heretofore limitations in the study of scan blindness.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Reflectarray Antennas for Independent Dual Linear and Circular
           Polarization Control
    • Authors: Ciaran Sean Geaney;Mehdi Hosseini;Sean Victor Hum;
      Pages: 5908 - 5918
      Abstract: This paper presents a dual-polarization reflectarray unit cell for wideband applications based on stacked Jerusalem crosses with a quarter-wavelength cell period. While unit cells with reduced interelement spacings can suffer from a reduction in phase range, the proposed cell exhibits a phase range of over 500° while maintaining a very independent response to two orthogonal linear polarizations. The unit cell is then integrated with a linear-to-circular polarizer to form a low profile fully planar structure which facilitates independent dual-circular polarization control using a modular design approach. Two prototypes, sized $13.3lambda _{0}$ by $19.9lambda _{0}$ at 20.5 GHz, are fabricated and measured, experimentally demonstrating the proposed concepts.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Large-Scale Phased Array Calibration
    • Authors: Jack J. Schuss;Thomas V. Sikina;Joseph E. Hilliard;Patrick J. Makridakis;Jeffrey Upton;Joseph C. Yeh;Stephen M. Sparagna;
      Pages: 5919 - 5933
      Abstract: One challenge in fielding large-scale phased array antennas is calibration of the antenna system, so that RF radiated beams can be accurately formed and steered. Here, we describe two new methods for calibrating large phased arrays, namely, the mobile Fourier gauge (MFG) and satellite-based calibration (SatCal) that permit rapid calibration of large phased arrays on site and that remove the need for expensive near-field facility testing that limits the size of the array sections that can be RF aligned. The MFG utilizes a known short RF line source that can be sequentially moved across the array using an existing crane; RF coupling measurements between this RF line source and the array elements made at different RF line source positions are vector summed, so as to form a known virtual RF line source that stretches the length of the array. A second independent method, SatCal, is presented that uses reflections from orbiting satellites to calibrate the array, either at the subarray or radiating element level. These calibration methods have been demonstrated on a large ${S}$ -band phased array and have resulted in array calibrations equivalent to within 5°, 0.7 dB rms (element level), or 4°, 0.6 dB rms (subarray level).
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • A W-Band Circular Box-Horn Antenna Array Radiating Sum and Difference
           Beams With Suppressed Sidelobe
    • Authors: Rong Shen;Xiuzhu Ye;Jinhua Xie;Zhijiao Chen;Cheng Jin;
      Pages: 5934 - 5942
      Abstract: A circular aperture box-horn array antenna operating in W-band, with sum and difference radiation beams, is presented in this paper. The circular aperture provides maximum usage efficiency of the area, which is well suited for a rotational platform. Nonuniform power distribution is applied for the radiating elements, contributing to a radiation pattern with suppressed sidelobe. In order to fit into the circular aperture, the feed networks are optimally arranged on a compact two-planar layer with four quadrants fed by the sum–difference network. The antenna array, along with its full-corporate feed networks, has a low profile and is easy to be machined. Measured results show that the peak gain is over 35.6 dBi from 92 to 94 GHz, with up to −21 dBi sidelobe level. In addition, the sum–difference contradictions are less than 4 dB, and the nulls of difference beams are below −25 dB.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Synthesis of Monopulse Antenna Patterns for Elliptical Phased Array
           Antennas With Different Peak Sidelobes Along the Principal Planes
    • Authors: Will P. M. N. Keizer;
      Pages: 5943 - 5950
      Abstract: This paper deals with the synthesis of monopulse antenna patterns, sum and difference ones, for planar phased array antennas with an elliptical aperture boundary featuring unequal ultra-low peak sidelobe levels (PSLLs) for the two principal planes of its far field. The used synthesis method is the iterative Fourier transform (IFT) approach. The elliptical planar phased array antenna involved in this synthesis contains 3656 open-ended waveguide radiating elements arranged in a triangular element grid and has an aperture width and height of $50lambda _{text {o}}$ and $25lambda _{text {o}}$ , respectively, where $lambda _{text {o}}$ is the wavelength at X-band center frequency 1.0fo. The simulated monopulse pattern results will be compared with those of a 4680-element rectangular planar phased array antenna having the same width, height, radiator type and triangular grid as the elliptical array antenna. The monopulse patterns of the rectangular array antenna meet the same unequal ultra-low PSLL requirements as those of the elliptical array antenna. It will be shown that the elliptical array antenna with a slightly enlarged aperture containing 4170 elements features on receive comparable or even better far-field performance characteristics as that of the rectangular array antenna. All reported far-field pattern simulations take mutual coupling between the array elements into account.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Deterministic Constrained Synthesis Technique for Conformal Aperiodic
           Linear Antenna Arrays—Part I: Theory
    • Authors: Diego Caratelli;Giovanni Toso;Oleg V. Stukach;Nikolay V. Panokin;
      Pages: 5951 - 5961
      Abstract: A deterministic approach to the synthesis of a general aperiodic arc or ring antenna array is presented and thoroughly detailed in this paper. The proposed technique, which is based on the auxiliary array pattern (AAP) concept, is aimed at the semianalytical determination of the optimal excitation tapering and array element angular distribution for mimicking a given radiation pattern mask, without resorting to any optimization procedure. This, in turn, enables a dramatic reduction in design times. The developed technique is validated by application to the synthesis of antenna arrays featuring different radiation pattern masks typically adopted in satellite communications and radar applications; the relevant results are reported in Part II.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Deterministic Constrained Synthesis Technique for Conformal Aperiodic
           Linear Antenna Arrays—Part II: Applications
    • Authors: Diego Caratelli;Giovanni Toso;Oleg V. Stukach;Nikolay V. Panokin;
      Pages: 5962 - 5973
      Abstract: The aim of this paper is to illustrate the application of the antenna placement methodology introduced in Part I for the deterministic synthesis of general conformal aperiodic arrays subject to multiple concurrent design constraints on the relevant layout and excitation tapering, as it is typically the case in satellite communications and radar applications. Antenna mutual coupling is not considered in the developed methodology; hence, to assess the sensitivity of the design procedure to such nonideality, a dedicated investigation has been conducted using rigorous full-wave electromagnetic modeling and experimental measurements collected on physical prototypes. The obtained results demonstrate the effectiveness and versatility of the proposed array synthesis approach, even in operative scenarios in which a significant deviation from the desired antenna operation is observed.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • An FSS-Backed Broadband Phase-Shifting Surface Array With Multimode
    • Authors: Xianjiang Zhong;He-Xiu Xu;Lei Chen;Wentao Li;Hao Wang;Xiaowei Shi;
      Pages: 5974 - 5981
      Abstract: This paper presents a novel broadband phase-shifting surface (PSS) element with frequency-selective surface (FSS) backing, which could independently control the phase of transmitted/reflected waves at high/low frequencies. Using the appealing features of basic building block, a high gain planar array antenna is designed and implemented by employing a set of these spatially varied phase-shifting elements. Fed by a Vivaldi antenna, the fabricated array is composed of $9 times 9$ elements, each carefully designed to exhibit the desired transmission/refection phase at high/low frequencies. Numerical and experimental results indicate that the fabricated array is capable of showing the functionalities of transmitarray and reflectarray at different frequencies. The peak gain of either transmission or reflection beam was found to be 18.8 dB, which was at least 10 dB higher than that of bare feed source.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Series- and Corner-Fed Planar Microstrip Antenna Arrays
    • Authors: Rinkee Chopra;Girish Kumar;
      Pages: 5982 - 5990
      Abstract: Linear arrays along radiating (E-plane) and nonradiating (H-plane) edges are designed for broadside radiation pattern at 5.8 GHz using U-shaped series- and corner-feed configurations, respectively. U-shaped feedlines are used to reduce the interelement spacing and size of the array. A 25-element radiating edge linear array provides 19.9 dBi gain with sidelobe level (SLL) and cross polar (X-pol) level of less than −15.3 and −33.8 dB, respectively. Nonradiating edge linear array is designed up to 31 elements using the corner-feed configuration to achieve 18 dBi gain with SLL and X-pol level of less than −15.2 and −22.5 dB, respectively. Furthermore, a planar array is designed using the series and corner feeds in E- and H-planes. A $15 times 15$ -element array is designed to achieve 24.4 dBi gain with SLL and X-pol level of less than −14.7 and −18.8 dB, respectively, in both the E- and H-planes. This array eliminates the need of complex-, multilayer-, and lossy-feed network and improves SLL and X-pol level. A planar array of $9 times 9$ elements is fabricated, and the measured results are in agreement with the simulated results.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Perfect Absorption by an Array of Lossy Dipoles Located Close to a Ground
    • Authors: Ofer Markish;Daniel Silverstein;Yehuda Leviatan;
      Pages: 5991 - 5996
      Abstract: This paper presents a thin absorbing structure comprising an array of finitely conductive terminal-loaded dipoles spaced about half a wavelength apart and located above a ground plane. We show that if the antennas are terminated with proper load impedance, instead of a conjugate-matched one, a perfect absorption can be attained even when the array lies close to the ground plane. We also identify a threshold height below which the absorption efficiency rapidly drops and perfect absorption cannot be realized. The idea is illustrated via a concrete example of array of dipoles printed with conductive ink technology on a Kapton HN flexible film backed by a rigid Rogers 4350B substrate. The array is designed for perfect absorption at 3.45 GHz when it is located one-tenth of a wavelength above the ground plane. Good agreement between simulation and measurement results is demonstrated.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Efficient Evaluation of Gradient Transmit-Arrays Through an Equivalent
           Dispersive Dielectric Description
    • Authors: Parinaz Naseri;Sérgio A. Matos;Eduardo B. Lima;Jorge R. Costa;Carlos A. Fernandes;Nelson J. G. Fonseca;
      Pages: 5997 - 6007
      Abstract: The growing popularity of transmit-arrays (TAs) for various antenna applications is calling for effective analysis and optimization methods. TAs are, usually, electrically large, comprising thousands of unit-cells formed by subwavelength metallic scatterers. Full-wave optimization cycles needed to meet stringent specifications in terms of gain, cross-polarization, bandwidth, scan-loss, etc., may be impaired by unrealistically required computational time and memory resources. To overcome this, we propose a modified homogenization method that, unlike other approaches, captures the internal reflections in the unit-cells and its resonances for each polarization, thus, correctly describing unit-cells’ frequency response in the band of interest. We define equivalent dispersive anisotropic media for gradient TAs. These surrogate models enable fast analysis and optimization of TAs without compromising the accuracy. As an example, we analyze a TA composed of phase rotation (PR) unit-cells. PR unit-cells present wideband low axial ratio for a TA but challenge the validation of existing homogenization methods. Detailed general description of the method is provided so that it can be applied to other unit-cells and avoid training time and resources required for machine learning-based methods. Using the surrogate cells, the full-wave analysis time and memory of the TA reduces 13 and 4 times, respectively.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Defocused Cylindrical Luneburg Lens Antennas With Phased Array Antenna
    • Authors: Peng-Yu Feng;Shi-Wei Qu;Shiwen Yang;
      Pages: 6008 - 6016
      Abstract: In this paper, a defocused cylindrical Luneburg lens antenna with phased array antenna (PAA) feed operating at 10 GHz is proposed. After equivalent and defocusing procedures, a defocused lens is developed, effectively dispersing the energy over the focal area. Furthermore, a 19-element dipole PAA, which has been partitioned into three linear subarrays, illuminates the defocused lens with the weighted excitation coefficients optimized by the introduced active element-lens pattern (AELP) method. Comprehensive analyses of the AELP method and classical conjugate field matching (CFM) method on deploying the PAA feed excitation coefficients are also performed. The simulated results show that the proposed PAA-fed defocused lens features a high-precision scanning across an ultra-wide angular range of ±81° with a 21.1 dBi peak gain, 3/7.5 dB gain drops as scan to 75°/81°, respectively. Besides, against traditional cylindrical Luneburg lens with switched feed elements, 5.4–3.3 dB gain enhancements and 11.9–6.6 dB effective isotropic radiated power (EIRP) improvements are obtained as the beam scans from 0° to 74°, except for the expansion of the maximum scan angle to 81°. In the experiment, the AELPs, as well as the whole PAA-fed defocused lens integrated with active modules for broadside scan, are measured, accurately evaluating the proposed design.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Synthesizing Uniform Amplitude Sparse Dipole Arrays With Shaped Patterns
           by Joint Optimization of Element Positions, Rotations and Phases
    • Authors: Foxiang Liu;Yanhui Liu;Kai Da Xu;Yong-Ling Ban;Qing Huo Liu;Y. Jay Guo;
      Pages: 6017 - 6028
      Abstract: This paper presents a novel method for synthesizing sparse dipole arrays with shaped patterns by joint optimization of element positions, rotations and phases. Such joint optimization exploits maximum available degrees-of-freedom under the assumption of uniform amplitude excitations to improve the shaped power pattern synthesis performance, and it leads to a reduced number of elements and simpler feeding network without using unequal power dividers for the array. The copolarization (COP) and cross-polarization patterns for a rotated dipole array are derived in a 2-D case, and then the vectorial shaped pattern synthesis problem is formulated as finding the optimal solution by maximally approaching the desired COP pattern shape under multiple constraints on the sidelobe level (SLL) and cross-polarization level (XPL). In addition, an asymmetric mapping method is incorporated into the proposed joint optimization, so that the minimum element spacing constraint can be also used for the synthesis of planar sparse dipole arrays. The comprehensive learning particle swarm optimization (CLPSO) algorithm is adopted to optimize the element positions, rotation angles and phases. A set of synthesis experiments including linear and planar rotated dipole arrays with a different pattern shape requirements are conducted to validate the effectiveness and robustness of the proposed approach. Synthesis results show that the proposed approach can save about 17.24% – 55.86% elements as well as many unequal power dividers for test cases.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Far-Field and Near-Field Physics of Extraordinary THz Transmitting
           Hole-Array Antennas
    • Authors: Miguel Camacho;Rafael R. Boix;Sergei A. Kuznetsov;Miguel Beruete;Miguel Navarro-Cía;
      Pages: 6029 - 6038
      Abstract: Despite three decades of effort, predicting accurately extraordinary transmission through subwavelength hole arrays has proven challenging. The lack of quantitative design and modeling capability to take into account the inherent complexity of high frequency instrumentation has prevented the development of practical high-performance components based on this phenomenon. This paper resorts to the Method of Moments to provide not only such missing quantitative prediction but also a theoretical framework to understand and shed more light on the far-field and near-field physics of the extraordinary terahertz (THz) transmission through subwavelength hole arrays under different illumination and detection conditions. An excellent agreement between the numerical and experimental results with various illumination and detection setups is obtained, demonstrating the suitability of this computationally efficient modeling tool to predict the response of extraordinary transmission structures in practical situations.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Broadband Frequency-Selective Rasorber With Varactor-Tunable
           Interabsorption Band Transmission Window
    • Authors: Lijie Wu;Shuomin Zhong;Jifu Huang;Taijun Liu;
      Pages: 6039 - 6050
      Abstract: In this paper, we present a frequency-selective rasorber with tunable transmission window located within the absorption band. The rasorber maintains a low reflectivity, which is less than −10 dB in broadband during the tuning process. An equivalent circuit model is provided as a guideline for the tunable rasorber design. Based on the model, a varactor-tunable rasorber composed of three stacked metallic layers is constructed and investigated. These layers include a frequency selective surface (FSS) loaded with resistors and varactors, a wire grid and a varactor-loaded bandpass FSS. The wire grids in the middle and bottom layers in combination with metallic vias provide the bias and grounding for the varactors, respectively. This configuration avoids using two separated bias networks for varactors on different layers, thus, averting undesirable responses associated with having more bias grids. A tunable rasorber prototype was fabricated and measured, showing that the passband can be tuned from 2.2 to 3.3 GHz by changing bias voltage from 4 to 22 V, with an insertion loss between 6.6 and 3.3 dB. A wide low-reflectivity band under normal incidence for double polarizations from 1.9 to 5.4 GHz is realized. This tunable rasorber has promising applications in broadband stealth facilities with integrated hopping communication functionality.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • PCB Laminates for Automotive Radar Antenna Modules Under Different
           Environmental Conditions
    • Authors: Jonathan Mayer;Manuel Martina;Thomas Gottwald;Thomas Zwick;
      Pages: 6051 - 6058
      Abstract: Radar systems have become more important in the automotive field, especially for autonomous driving. A crucial part of the hardware is the antenna which is connected by lines to the radar chip. These components are usually built on printed circuit boards (PCBs) that have to fulfill high automotive requests under all environmental conditions. As a consequence, material properties are a critical factor for the functionality and reliability of systems, like-wise new materials are available in the market. Fourteen interesting materials of different classes [polytetrafluorethylene (PTFE), polyphenyl ether (PPE), epoxy-based resin, and liquid crystal polymer (LCP)] were evaluated in this work at their initial state, while heating to 125 °C and after storage with 85% relative humidity (RH) at 85 °C. It is shown that there are new candidates for millimeter wave applications beyond the PTFE materials. Nevertheless, it is necessary to test each material individually for its properties and optimize the parameters in simulation because they differ from the values in the datasheet. In addition, the properties depend on the used line setup, in this work microstrip lines. For the measurements, multiline thru-reflect-line (TRL) calibration and ring resonators were used and give a good overview by loss and effective permittivity depending on the environmental condition.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Active Frequency Selective Surface to Switch Between Absorption and
           Transmission Band With Additional Frequency Tuning Capability
    • Authors: Ratanak Phon;Saptarshi Ghosh;Sungjoon Lim;
      Pages: 6059 - 6067
      Abstract: This study realized a polarization-insensitive active frequency selective surface (AFSS) that simultaneously exhibited mode switching and frequency tunable capacity. Its geometry comprised periodic metallic patterns printed on opposite sides of a dielectric substrate, with varactors and p-i-n diodes mounted on the top and bottom layers, respectively. The proposed AFSS switches between transmission and absorption modes by regulating the p-i-n diodes (OFF and ON states). Transmission and absorption frequencies can also be continuously tuned by changing the bias voltage across the varactor diodes. To realize polarization independence, metallic patterns, lumped components, and biasing configurations were symmetrically patterned. The equivalent circuit and parametric studies were considered to explain AFSS switching and tuning behaviors. The proposed multifunction and frequency tuning responses were experimentally demonstrated by fabricating a prototype with $17 times 17$ unit cells. The bandpass frequency can be tuned from 3.70 to 4.27 GHz with a 1.96–4.30 dB insertion loss in the transmission mode, and the absorption frequency can be regulated from 4.28 to 5.12 GHz with 78.77%–90.78% absorptivity.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Near-Field Multibeam Generation by Tensorial Metasurfaces
    • Authors: Ioannis Iliopoulos;Mounir Teniou;Massimiliano Casaletti;Patrick Potier;Philippe Pouliguen;Ronan Sauleau;Mauro Ettorre;
      Pages: 6068 - 6075
      Abstract: The generation of several beams with strict radiation requirements in the field of a radiating aperture is demonstrated here. An optimization scheme is adopted to derive the aperture-field distribution generating the required near-field radiation. The optimization tool is based on a set-theoretic approach and takes into account field constraints on the radiation profile and polarization. The challenging case of generating four independent beams in the near field of a radiating aperture and with different polarizations is then considered. A tensorial metasurface is adopted to synthesize the derived aperture field profile to fully control the amplitude and phase distribution of the radiating aperture. Measurement results at 20 GHz validate the proposed approach.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Novel FDTD Scheme for Analysis of Frequency- Dependent Medium Using Fast
           Inverse Laplace Transform and Prony’s Method
    • Authors: Jerdvisanop Chakarothai;
      Pages: 6076 - 6089
      Abstract: A novel finite-difference time-domain (FDTD) approach is proposed for the analysis of wave propagation in a general frequency-dependent medium. In the proposed method, formulation of the fractional derivatives in the time-domain representation is circumvented by using the fast inverse Laplace transform (FILT) and Prony’s method. The FILT is used to transform the dispersion expressed in a frequency-domain response into a time-domain response, and Prony’s method is utilized to extract the parameters and transform the time-domain responses into those in the z-domain so that they can be incorporated into the FDTD method directly. The update equation of the electric field in the FDTD method is then formulated by using the z-transformation. Stability analysis of the proposed scheme is also investigated by means of the root-locus method. Reflection coefficients of dispersive media, such as Debye, Cole–Cole, Davidson–Cole, and Havriliak–Negami media simulated in a 1-D domain and a three-layered biological medium of skin, fat, and muscle tissues inside a waveguide with a TE10 fundamental mode in a 2-D domain, are found to be in good agreement with those obtained by an analytical method over a broad frequency range, demonstrating the validity of the proposed FDTD scheme.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Twofold Domain Decomposition Method for the Analysis of Multiscale
           Composite Structures
    • Authors: Ping-Hao Jia;Lin Lei;Jun Hu;Yongpin Chen;Kui Han;Wei-Feng Huang;Zaiping Nie;Qing Huo Liu;
      Pages: 6090 - 6103
      Abstract: A nonconformal twofold domain decomposition method (TDDM) based on the hybrid finite element method-boundary element method (FEM-BEM) is proposed for analyzing 3-D multiscale composite structures. The proposed TDDM starts by partitioning the composite object into a closed exterior boundary domain and an interior volume domain. The interior and exterior boundary value problems are coupled to each other through the Robin transmission conditions (RTCs). Both domains are then independently decomposed into subregions to facilitate computation. Specifically, FEM-DDM with the second order transmission conditions (SOTCs) is employed for the interior domain, and BEM-discontinuous Galerkin (BEM-DG) based on the combined field integral equation (CFIE) is applied for the exterior boundary domain. The proposed TDDM allows for nonconformal discretization between any touching subdomains. Without the introduction of a stabilization term that relies on a line integral over intersection of nonmatching meshes and relevant terms involving surface-line integrals, the proposed TDDM provides an effective domain decomposition (DD) preconditioner for the global system. Numerical examples are presented, and the comparisons of the simulation results with FEM-BEM confirm the validity and accuracy of TDDM. Moreover, its ability to model practical large-scale and multiscale targets is also demonstrated.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Realistic Rain Model for the Estimation of the Rainfall Rate From Radar
    • Authors: Keyla M. Mora Navarro;Emanoel Costa;Carlos A. Morales Rodriguez;Sandra Cruz-Pol;Leyda V. León Colón;
      Pages: 6104 - 6114
      Abstract: This contribution describes a realistic rain model that considers a cluster of axis-symmetric but flattened raindrops with a specified shape–size relation, a raindrop size distribution, and a distribution of orientation angle of the symmetry axis. The backscattering cross section and specific attenuation due to the rain medium are determined by the extended boundary condition method. The model is applied to data from two X-band radars to estimate reflectivity and rainfall rate, considering attenuation effects during the two-way propagation between the radar and each sampled rain volume. The results are then compared with corresponding ones from well-established attenuation-correction methods. One of these methods, which relies on unattenuated reflectivities measured by an S-band radar, has been carefully validated by a previous study. The reasonable agreement between the two methods indicates that the proposed model may be a suitable option to estimate reflectivity and rainfall rate fields based on X-band radar data, particularly when no such references are available.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • High-Resolution ITU-R Cloud Attenuation Model for Satellite Communications
           in Tropical Region
    • Authors: Feng Yuan;Yee Hui Lee;Yu Song Meng;Shilpa Manandhar;Jin Teong Ong;
      Pages: 6115 - 6122
      Abstract: In this paper, the precipitable water vapor (PWV) data from Global Navigation Satellite System (GNSS) is introduced into ITU-R cloud attenuation model for higher temporal and spatial resolution for a tropical region. The revised model incorporates PWV value for estimation of cloud integrated liquid water content (ILWC) and then determines the cloud attenuation. In this study, ILWC along the propagation path is obtained by processing radiosonde vertical profile using the combination of a water vapor pressure cloud detection model and the Salonen and Uppala liquid water density model. From the analysis of 2 years of radiosonde data from eight sites within the tropical region, the results show that the ILWC along the path can be approximated by a power function relationship with the PWV. The estimated cloud attenuation using the improved model is compared with the values calculated using the ITU-R model and the cloud attenuation derived from a Ka-band beacon data. The results show that the proposed model is in good agreement with the ITU-R model at high percentage of time exceedance for the thin layer of stratus clouds and matches well with cloud attenuation suffered from beacon signal at low percentage of time exceedance for the thick layer of cumulonimbus clouds.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • 3-D Fadings Structure Analysis in Straight Tunnels Toward Communication,
           Localization, and Navigation
    • Authors: Carlos Rizzo;Francisco Lera;José Luis Villarroel;
      Pages: 6123 - 6137
      Abstract: Tunnels represent strong multipath environments for communications, where wireless propagation differs from regular indoor or outdoor scenarios. Moreover, with an adequate operating frequency choice, a tunnel behaves as an oversized waveguide, extending the communication range but affecting the signal with strong fadings. These fadings have been closely studied in the literature in the longitudinal dimension (tunnel length). Nevertheless, they also occur in the cross section, where they have only been analyzed statistically and on a small scale. In this paper, we present the results from an extensive measuring campaign carried out at the Somport tunnel, in Spain. We have adopted the modal theory approach to analyze the large-scale fadings (also known as slow fadings) in the longitudinal, transversal, and vertical dimensions. More specifically, the modes’ geometry allowed for the adequate placement of transmitters to create different periodic fading structures and to virtually divide the tunnel cross section into sectors, where the fadings presented a phase shift of 180°. This study enabled the development of large-scale spatial diversity schemes and navigation techniques to improve communication and localization inside these scenarios.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Physics-Inspired Convolutional Neural Network for Solving Full-Wave
           Inverse Scattering Problems
    • Authors: Zhun Wei;Xudong Chen;
      Pages: 6138 - 6148
      Abstract: In this paper, to bridge the gap between physical knowledge and learning approaches, we propose an induced current learning method (ICLM) by incorporating merits in traditional iterative algorithms into the architecture of convolutional neural network (CNN). The main contributions of the proposed method are threefold. First, to the best of our knowledge, it is the first time that the contrast source is learned to solve full-wave inverse scattering problems (ISPs). Second, inspired by the basis-expansion strategy in the traditional iterative approach for solving ISPs, a combined loss function with multiple labels is defined in a cascaded end-to-end CNN (CEE-CNN) architecture to decrease the nonlinearity of objective function, where no additional computational cost is introduced in generating extra labels. Third, to accelerate the convergence speed and decrease the difficulties of the learning process, the proposed CEE-CNN is designed to focus on learning the minor part of the induced current by introducing several skip connections and to bypass the major part of induced current to the output layers. The proposed method is compared with the state-of-the-art of deep learning scheme and a well-known iterative ISP solver, where numerical and experimental tests are conducted to verify the proposed ICLM.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Design of a Portable Verification Artifact for Millimeter-Wave-Frequency
           Channel Sounders
    • Authors: Jos N. H. Dortmans;Jeanne T. Quimby;Kate A. Remley;Dylan F. Williams;Jelena Senic;Ruoyu Sun;
      Pages: 6149 - 6158
      Abstract: We developed a portable and traceable artifact to verify the millimeter-wave-frequency channel sounders (CSs) under static conditions. It is designed to create several multipath profiles with one direct path and up to two multipath components (MPCs) to be used during the verification of a CS. The verification artifact shows that the CS we tested measures extra MPCs possibly due to internal reflections in the CS. While these differences are not likely to significantly change most of the channel metrics, they do indicate nonidealities in the CS that might need to be addressed depending on the application.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Near-Field Antenna Pattern Measurements in Highly Reflective Environments
    • Authors: Josef Knapp;Thomas F. Eibert;
      Pages: 6159 - 6169
      Abstract: The far-field pattern of an antenna under test is determined from the near-field measurements in a highly reflective environment. The proposed post-processing effectively combines time gating and spatial filtering of the radiated fields. Time gating utilizes frequency diversity, while spatial filtering makes use of probe diversity and source localization. Different probe locations are used to form a virtual array, which focuses the fields at the antenna volume. The possible scatterers are illuminated as little as possible. The weighting coefficients for the virtual array are found by solving a field synthesis problem. The effects of time gating and spatial filtering are analyzed separately. A measurement setup is described in a highly reflective chamber involving fully spherical measurements with probes in up to 120 different positions and with 1001 frequencies. Time gating yields better results, but a combination of both methods is necessary to achieve an estimated accuracy of −30 dB for the considered S-band and −40 dB for the considered Ku-band antenna.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • A Design of Compact Ultrawideband Circularly Polarized Microstrip Patch
    • Authors: Chao Sun;
      Pages: 6170 - 6175
      Abstract: As it is well known, microstrip patch antennas are commonly used, because they are compact and it is easy to achieve a unidirectional radiation pattern with circular polarization. However, the bandwidth of patch antennas is quite narrow, which limits their use in ultrawideband (UWB) applications. In this communication, a wideband enhancement method based on a multimode analysis of patch antennas is proposed. By adding suitable shorting loads on the patch, the resonance frequency of the higher order modes TM20, TM30, TM40, and TM50 is decreased and combined with the dominant mode (TM10) one. These five modes provide a wide operating band. Using this bandwidth enhancement method, a compact UWB patch antenna with unidirectional radiation pattern and circular polarization is designed. The size of the patch is only $0.5lambda _{0} times 0.5lambda _{0}$ and the height is only $0.1lambda _{0}$ ( $lambda _{0}$ is the free space wavelength at the center frequency). The simulation and measured results show that the proposed antenna has a bandwidth of 85% for S11 < −10 dB and realized RHCP gain >6 dBic from 2.2 to 5.5 GHz. The proposed design method is suitable for UWB CP patch antenna applications.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • A Wideband Differentially Fed Dual-Polarized Antenna With Wideband
           Harmonic Suppression
    • Authors: Le-Hu Wen;Steven Gao;Qi Luo;Qingling Yang;Wei Hu;Yingzeng Yin;Xiaofei Ren;Jian Wu;
      Pages: 6176 - 6181
      Abstract: A wideband differentially fed dual-polarized antenna with wideband harmonic suppression is presented. The radiating structure is composed of open slots, stair-shaped strips, and a square patch. Eight open slots are etched on the four corners of the square patch to realize symmetrical radiation and low cross-polarization for orthogonal polarizations. Stair-shaped strips are not only used to excite the open slots, but also introduce the monopole resonance. In addition, patch resonance is excited on the center square patch. For matching these different resonances, shorted microstrip lines are utilized to achieve the wide impedance bandwidth. Moreover, compact stepped impedance resonators are elaborately introduced on the top of the patch to achieve wideband harmonic suppression without any increase of the antenna footprint. The proposed antenna is designed, fabricated, and measured to verify the design method. The measured results demonstrate that the proposed antenna has the impedance bandwidth of 1.70–2.81 GHz for Sdd11 < −15 dB with high isolation of 39 dB. Moreover, wideband harmonic suppression is measured from 3 to 9 GHz with the Sdd11 higher than −2.2 dB, and the corresponding harmonic gain lower than −5.3 dBi. In addition, a stable gain of 7.2–7.9 dBi and beamwidth of 63°–71° are achieved for base station applications.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • $pi$+ +-Shaped+Decoupling+Structure&rft.title=IEEE+Transactions+on+Antennas+and+Propagation&rft.issn=0018-926X&;&rft.aufirst=Saou-Wen&;Cheng-Tse+Lee;Ya-Wen+Hsiao;">Compact Two-Inverted-F-Antenna System With Highly Integrated $pi$ -Shaped
           Decoupling Structure
    • Authors: Saou-Wen Su;Cheng-Tse Lee;Ya-Wen Hsiao;
      Pages: 6182 - 6186
      Abstract: Conventional decoupling technique uses the resonator-based grounded structure that separates two antennas at a distance for improving port-to-port isolation. The decoupling structure usually requires certain space, which increases the overall antenna size. In this communication, a small $pi $ -shaped structure that can be highly integrated into a very compact two-inverted-F-antenna (IFA) system is presented. The two-IFA design occupies a size of 5 mm $times38$ mm (about $0.04lambda times 0.30lambda $ at 2.4 GHz) with two symmetrical IFAs facing each other by a gap of 2 mm only. Each IFA is capable of covering the 2.4 GHz (2400–2484 MHz) and 5 GHz (5150–5825 MHz) wireless local area network (WLAN) bands. The $pi $ -shaped decoupling structure is encircled by the IFAs and comprises two shunt capacitors and a series inductor. By properly selecting the capacitance and the inductance, the isolation between the IFAs in 2.4 GHz band can be largely enhanced. In addition, because of current null arrangements of the 5 GHz band, the proposed design is inherently decoupled over the higher band. The results show that good isolation >16 dB over the 2.4 and 5 GHz bands can be attained. It is also noted that the decoupling bandwidth of the present decoupling structure is narrow.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • A Novel Substrate-Integrated Coaxial Line Transverse Slot Array Antenna
    • Authors: Bing Liu;Yu Ma;Ren R. Zhao;Wen Q. Xing;Zi J. Guo;
      Pages: 6187 - 6192
      Abstract: In this communication, a novel transverse slot array with standing-wave excitation using substrate-integrated coaxial line (SICL) technique is proposed. The transverse series slots are arranged with a uniform spacing of one guided wavelength and centered over the inner strip of the SICL. A $5times 1$ element linear subarray is designed with suppressed sidelobe levels (SLLs). A tapering power divider is then adopted to feed eight such subarrays and finally a $5times 8,,2$ -D array is fabricated and tested for demonstration. A −10 dB impedance bandwidth (BW) from 33.87 to 35.10 GHz (3.57% at 34.5 GHz) is measured out with a peak broadside gain of 18.82 dBi. The E-plane and H-plane SLLs are −18.4 and −19.2 dB, respectively. Agreement between theory and experiment has been found to be good for both the linear array and the proposed antenna.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Gain-Enhanced Planar Log-Periodic Dipole Array Antenna Using Nonresonant
    • Authors: Guohua Zhai;Xi Wang;Rensheng Xie;Jin Shi;Jianjun Gao;Bo Shi;Jun Ding;
      Pages: 6193 - 6198
      Abstract: In this communication, a novel nonresonant metamaterial (MTM) structure is proposed to enhance the gain of the clamped-mode planar log-periodic dipole array (CMPLPDA) antenna fed by substrate integrated waveguide. The proposed MTM structures composed of a series of metallic semiring patches are printed on both sides of the antenna substrate, featuring low loss, broadband, and easy integration. Different arrangements of the nonresonant MTM with respect to the dipoles of the CMPLPDA antenna are investigated and compared. The proposed gain-enhanced method based on the nonresonant MTM has been studied through both numerical simulations and experiments. Compared to the original CMPLPDA antenna without any MTM inclusions, the proposed CMPLPDA antenna fully loaded with nonresonant MTM inclusions exhibits a gain enhancement of at least 1.6 dB (up to 4 dB at 27 GHz) within the operating band of 26–40 GHz in the simulations, which is also validated by the experiments.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • An Integrated Radiation and Scattering Performance Design Method of
           Low-RCS Patch Antenna Array With Different Antenna Elements
    • Authors: Ying Liu;Yongtao Jia;Wenbo Zhang;Yizhe Wang;Shuxi Gong;Guisheng Liao;
      Pages: 6199 - 6204
      Abstract: In this communication, a novel integrated radiation and scattering performance design method of patch antenna array is proposed that can realize good radiation and low radar cross section (RCS) characteristics simultaneously without any additional RCS reduction structures except for the antenna elements. Two different antenna elements, which have similar radiation performances and different reflection phases, are used to form the array. By using different feed and patch structures, both the desired radiation and scattering characteristics of the two antenna elements can be controlled separately. Thus, a similar radiation performance and a 180° reflection phase difference can be obtained simultaneously by adjusting the size of the patches and the length of the slots on the ground plane. The simulation results show that the proposed integrated design array has approximately the same radiation performances as the arrays with uniform elements. In addition, the monostatic RCS of the proposed array is significantly reduced from 4 to 8 GHz, with a maximum reduction value of 23 dB. To validate the simulation results, prototypes of the integrated design antenna array with $4times 4$ elements are fabricated and measured. The measured results are in good agreement with the simulated results.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • A 1-Bit Bidirectional Reconfigurable Transmit-Reflect-Array Using a
           Single-Layer Slot Element With PIN Diodes
    • Authors: Min Wang;Shenheng Xu;Fan Yang;Maokun Li;
      Pages: 6205 - 6210
      Abstract: The design and experiment of a single-layer reconfigurable bidirectional antenna are presented for the first time, which combines the dynamic radiation characteristics of both reconfigurable transmitarray and reflectarray. The proposed element consists of a single-layer circular ring slot etched on one side of a dielectric substrate and two PIN diodes integrated across the slot. By turning them ON or OFF simultaneously, the induced current directions are reversed, thus achieving two phase states with 180° phase difference. The bidirectional radiation is achieved by utilizing the continuity of the cross-polarized electric field on the surface. A $C$ -band $16 times 16$ reconfigurable prototype with a side length of 400 mm is designed, fabricated, and measured. The measured results demonstrate the ability to electronically scan both the transmitted and reflected beams simultaneously. The measured gains of the transmitted and reflected beams at 5.35 GHz are 17.2 dBi and 15.4 dBi, respectively. The wideband 3-dB gain bandwidths are 32% for both the transmitted and reflected beams. The proposed design can achieve high-gain large-angle electronic scanning beams with distinctive advantages of being wideband, lightweight, low cost, and easy to fabricate and, hence, is suitable for bidirectional wireless communication applications.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • An Air Cavity-Fed Circularly Polarized Magneto-Electric Dipole Antenna
           Array With Gap Waveguide Technology for mm-Wave Applications
    • Authors: Jianyin Cao;Hao Wang;Shanxiang Mou;Permanand Soothar;Jingwei Zhou;
      Pages: 6211 - 6216
      Abstract: In this communication, a low profile $4 times 8$ air cavity-fed circularly polarized (CP) planar antenna array with high performance for W-band is proposed. This antenna array is composed of two parts: low-loss gap waveguide (GWG) feeding network and high performance magneto-electric (ME) dipole antennas. The antenna elements are fed by the transverse coupling slots right above an air-filled high-mode cavity with checkerboard structure. Moreover, a four-way ridge GWG (RGWG) power divider with transition from RGWG to groove GWG (GGWG) is designed to excite the high-mode cavity. By properly arranging the position and size of coupling slots, each ME dipoles are excited with in-phase property. Periodic pins are arranged around both the GWG transmission line and the air cavity to create a stop band and resonant frequency. The high-mode air cavity is realized using shorted pins to split the electromagnetic field into shorted-end GGWG. Thus, the normal GWG feeding technology with a GWG power divider and a $2 times 2$ air cavity in different layers are combined in a single layer. The transmission loss and substrate loss of this metallic single-layer feeding network are reduced, as well as the array profile. Each CP ME dipole antenna is etched on the printed circuit board (PCB) with stable radiation pattern and wide axial ratio (AR) bandwidth performance. The proposed $4 times 8$ planar antenna array is simulated and fabricated to validate the design. A measured 3 dB AR bandwidth of 17% and a gain of up to 23 dBi have been achieved. The impedance matching is lower than −10 dB over the frequency band with an overall boresight gain of above 19 dBi.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • 90 GHz, 3-D Scattered Field Measurements for Investigation of Foreign
           Object Debris
    • Authors: Florence Nsengiyumva;Claire Migliaccio;Laurent Brochier;Jérôme Lanteri;Jean-Yves Dauvignac;Christian Pichot;
      Pages: 6217 - 6222
      Abstract: Scattering properties of millimeter waves (mmW) remain relatively unknown compared to lower frequency bands, although their study is of interest considering the increasing number of civil applications, especially in the $W$ -band. In this communication, we present an efficient measurement setup that provides scattering measurements with spatial and polarization diversities. The targeted application is foreign object debris (FOD) detection and identification for surveillance of airport runways. Most existing systems are monostatic but rapid advances in mmW technology pushes toward the deployment of multistatic radars on either side of airport runways. In the following, we investigate the contribution of multistatic measurements with a special focus on the reconstruction of glass and brake pad debris, courtesy of DGAC (French civil aviation). We also present an efficient approach for making images of FODs. For this, we process scattered field measurements with an additive (with respect to polarization) backpropagation algorithm. First images include all measured points taken from the upper hemisphere. In order to get closer to the final application, we restrict the field of view to receivers facing the transmitter. Both approaches provide very good shape reconstruction of the glass debris and the central zone of the brake pad. To the best of our knowledge, this is the first time that full-3-D measurements have been conducted on FODs in the $W$ -band. It is also the first example of a 3-D qualitative image of FOD obtained from measured data in the $W$ -band.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Single-Frequency Multipath Diagnosis in an Anechoic Chamber of a Hybrid
           Far-Field Antenna Measurement System
    • Authors: Kuan-An Chen;Hsi-Tseng Chou;
      Pages: 6223 - 6228
      Abstract: In this communication, we present an antenna radiation measurement calibration method based on a multipath diagnosis in an anechoic chamber of a hybrid near- and far-field antenna measurement system. With the near-field (NF) scan functionality of the method, one may be able to discriminate multipath signals using the measured data at various positions at a single frequency. In this technique, a virtual array of receiving (RX) probes by their grid of locations is created to collect the data for further processing by a matrix pencil method (MPM) for determining the characteristics of multipath signals. Then, a reference antenna is employed to produce a calibration matrix factor (CMF) that can be stored in a file and be directly incorporated with the measurement of the radiation of any antenna under test (AUT) to derive its corrected radiation patterns without the need for further calibration by a multifrequency scan. The simulation and measurement examples are presented to demonstrate the feasibility and utilization of this calibration methodology.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Erratum to “Fundamental Limitations for Antenna Radiation
    • Authors: Morteza Shahpari;David V. Thiel;
      Pages: 6229 - 6229
      Abstract: Recently, a fundamental limit for antenna radiation efficiency was proposed in [1]. Although valid for most antenna applications, a clarification is needed with regard to the fundamental limit expressed by [1 eqs. (14) and (15)]. This clarification is to draw the attention if one like to extend (14) and (15) to cylinders with radius in the range of skin depth. However, it does not invalidate the original work since the skin depth was assumed to be much smaller than the thickness of the object. This point was initially raised by J. Cahill from Technology Service Corporation.
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Introducing IEEE Collabratec
    • Pages: 6230 - 6230
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • IEEE Open Access Publishing
    • Pages: 6231 - 6231
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
  • Member Get-A-Member (MGM) Program
    • Pages: 6232 - 6232
      PubDate: Sept. 2019
      Issue No: Vol. 67, No. 9 (2019)
School of Mathematical and Computer Sciences
Heriot-Watt University
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