Subjects -> ENGINEERING (Total: 2688 journals)
    - CHEMICAL ENGINEERING (229 journals)
    - CIVIL ENGINEERING (237 journals)
    - ELECTRICAL ENGINEERING (176 journals)
    - ENGINEERING (1325 journals)
    - ENGINEERING MECHANICS AND MATERIALS (452 journals)
    - HYDRAULIC ENGINEERING (56 journals)
    - INDUSTRIAL ENGINEERING (98 journals)
    - MECHANICAL ENGINEERING (115 journals)

ENGINEERING (1325 journals)            First | 1 2 3 4 5 6 7 | Last

Showing 201 - 400 of 1205 Journals sorted alphabetically
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 8)
Control Engineering Practice     Hybrid Journal   (Followers: 46)
Control Theory and Informatics     Open Access   (Followers: 9)
Corrosion Science     Hybrid Journal   (Followers: 23)
CT&F - Ciencia, Tecnología y Futuro     Open Access  
CTheory     Open Access  
Current Applied Physics     Full-text available via subscription   (Followers: 4)
Current Applied Science and Technology     Open Access  
Current Journal of Applied Science and Technology     Open Access  
Current Research in Nanotechnology     Open Access   (Followers: 23)
Current Science     Open Access   (Followers: 116)
Dams and Reservoirs     Hybrid Journal   (Followers: 3)
Data-Centric Engineering     Open Access  
Decision Making : Applications in Management and Engineering     Open Access   (Followers: 1)
Design Journal : An International Journal for All Aspects of Design     Hybrid Journal   (Followers: 33)
Designed Monomers and Polymers     Open Access   (Followers: 1)
Designs     Open Access  
Designs, Codes and Cryptography     Hybrid Journal   (Followers: 7)
Development Engineering     Open Access   (Followers: 3)
Diálogos Interdisciplinares     Open Access  
Diffusion Foundations     Full-text available via subscription   (Followers: 4)
Digital Signal Processing     Hybrid Journal   (Followers: 34)
Dinamisia : Jurnal Pengabdian Kepada Masyarakat     Open Access  
Discrete Optimization     Full-text available via subscription   (Followers: 7)
Dokuz Eylül Üniversitesi Denizcilik Fakültesi Dergisi     Open Access  
Düzce Üniversitesi Bilim ve Teknoloji Dergisi / Duzce University Journal of Science & Technology     Open Access  
Dyes and Pigments     Hybrid Journal   (Followers: 1)
Dynamical Systems : An International Journal     Hybrid Journal  
E&S Engineering and Science     Open Access  
e-Phaïstos : Revue d’histoire des techniques / Journal of the history of technology     Open Access  
EAU Heritage Journal Science and Technology     Open Access   (Followers: 1)
El-Cezeri Fen ve Mühendislik Dergisi / El-Cezeri Journal of Science and Engineering     Open Access  
Electromagnetics     Hybrid Journal   (Followers: 13)
Electrophoresis     Hybrid Journal   (Followers: 18)
Elkawnie : Journal of Islamic Science and Technology     Open Access  
Emerging Science Journal     Open Access   (Followers: 1)
Emitter : International Journal of Engineering Technology     Open Access  
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations     Open Access  
Energies     Open Access   (Followers: 4)
Energy and Power Engineering     Open Access   (Followers: 23)
Energy Conversion and Management     Hybrid Journal   (Followers: 15)
Energy Conversion and Management : X     Open Access   (Followers: 1)
Energy Engineering     Full-text available via subscription   (Followers: 8)
Energy for Sustainable Development     Hybrid Journal   (Followers: 13)
Energy Science & Engineering     Open Access   (Followers: 6)
Energy Science and Technology     Open Access   (Followers: 10)
Energy Sources, Part A: Recovery, Utilization, and Environmental Effects     Hybrid Journal   (Followers: 1)
Energy Sources, Part B: Economics, Planning, and Policy     Hybrid Journal   (Followers: 7)
Energy Systems     Hybrid Journal   (Followers: 11)
EnergyChem     Hybrid Journal   (Followers: 1)
Engenharia de Interesse Social     Open Access  
ENGEVISTA     Open Access  
Engineer : Journal of the Institution of Engineers, Sri Lanka     Open Access  
Engineering     Open Access   (Followers: 1)
Engineering & Technology     Hybrid Journal   (Followers: 22)
Engineering Analysis with Boundary Elements     Hybrid Journal   (Followers: 2)
Engineering Computations     Hybrid Journal   (Followers: 3)
Engineering Economics     Open Access   (Followers: 4)
Engineering Economist, The     Hybrid Journal   (Followers: 4)
Engineering Failure Analysis     Hybrid Journal   (Followers: 68)
Engineering Geology     Hybrid Journal   (Followers: 16)
Engineering Journal of Research and Development     Open Access  
Engineering Management in Production and Services     Open Access  
Engineering Management Research     Open Access   (Followers: 6)
Engineering Optimization     Hybrid Journal   (Followers: 19)
Engineering Reports     Open Access  
Engineering Science and Technology, an International Journal     Open Access   (Followers: 1)
Engineering Sciences     Open Access  
Engineering Studies     Hybrid Journal   (Followers: 1)
Engineering With Computers     Hybrid Journal   (Followers: 5)
Engineering, Technology & Applied Science Research     Open Access   (Followers: 1)
ENP Engineering Science Journal     Open Access  
Entramado     Open Access  
Entre Ciencia e Ingeniería     Open Access  
Entropy     Open Access   (Followers: 5)
Environmental & Engineering Geoscience     Full-text available via subscription   (Followers: 5)
Environmental and Ecological Statistics     Hybrid Journal   (Followers: 7)
Environmetrics     Hybrid Journal  
Épités - Épitészettudomány     Full-text available via subscription   (Followers: 1)
EPJ Photovoltaics     Open Access   (Followers: 2)
Ergonomics in Design: The Quarterly of Human Factors Applications     Hybrid Journal   (Followers: 21)
ESAIM: Control Optimisation and Calculus of Variations     Open Access   (Followers: 2)
ESAIM: Mathematical Modelling and Numerical Analysis     Open Access   (Followers: 5)
ESAIM: Proceedings     Open Access  
eScience     Open Access   (Followers: 1)
Estuaries and Coasts     Hybrid Journal   (Followers: 22)
EUREKA : Physics and Engineering     Open Access  
Euro-Mediterranean Journal for Environmental Integration     Hybrid Journal  
European Journal of Combinatorics     Full-text available via subscription   (Followers: 3)
European Journal of Engineering Education     Hybrid Journal   (Followers: 9)
European Journal of Lipid Science and Technology     Hybrid Journal   (Followers: 1)
European Journal of Mass Spectrometry     Hybrid Journal   (Followers: 16)
European Physical Journal - Applied Physics     Full-text available via subscription   (Followers: 19)
European Transport Research Review     Open Access   (Followers: 22)
Evolutionary Intelligence     Hybrid Journal   (Followers: 2)
Evolving Systems     Hybrid Journal  
Experimental and Computational Multiphase Flow     Hybrid Journal  
Experimental Techniques     Hybrid Journal   (Followers: 51)
Experiments in Fluids     Hybrid Journal   (Followers: 17)
Farm Engineering and Automation Technology Journal     Open Access  
Fibers and Polymers     Full-text available via subscription   (Followers: 4)
FIGEMPA : Investigación y Desarrollo     Open Access   (Followers: 1)
Filtration & Separation     Full-text available via subscription   (Followers: 4)
Finite Fields and Their Applications     Full-text available via subscription   (Followers: 5)
Fırat University Turkish Journal of Science & Technology     Open Access  
Fire Science Reviews     Open Access   (Followers: 12)
Flexible Services and Manufacturing Journal     Hybrid Journal   (Followers: 2)
Flow, Turbulence and Combustion     Hybrid Journal   (Followers: 30)
Fluid Dynamics     Hybrid Journal   (Followers: 27)
Fluid Phase Equilibria     Hybrid Journal   (Followers: 4)
Focus on Catalysts     Full-text available via subscription  
Focus on Pigments     Full-text available via subscription   (Followers: 3)
Focus on Powder Coatings     Full-text available via subscription   (Followers: 5)
Focus on Surfactants     Full-text available via subscription   (Followers: 2)
Food Engineering Reviews     Hybrid Journal   (Followers: 2)
Food Science and Technology     Open Access   (Followers: 2)
Forces in Mechanics     Open Access   (Followers: 4)
Formación Universitaria     Open Access   (Followers: 4)
FORMakademisk - forskningstidsskrift for design og designdidaktikk     Open Access   (Followers: 2)
Formal Methods in System Design     Hybrid Journal   (Followers: 6)
Forschung     Hybrid Journal   (Followers: 1)
Forschung im Ingenieurwesen     Hybrid Journal  
Foundations and Trends in Systems and Control     Full-text available via subscription   (Followers: 4)
Foundations and Trends® in Communications and Information Theory     Full-text available via subscription   (Followers: 6)
Foundations and Trends® in Electronic Design Automation     Full-text available via subscription   (Followers: 1)
Foundations of Science     Hybrid Journal   (Followers: 1)
Frontiers in Aerospace Engineering     Open Access   (Followers: 20)
Frontiers in Energy     Hybrid Journal   (Followers: 4)
Frontiers in Nanotechnology     Open Access   (Followers: 1)
Frontiers of Environmental Science & Engineering     Hybrid Journal   (Followers: 3)
Fuel and Energy Abstracts     Full-text available via subscription   (Followers: 7)
Fuel Cells     Hybrid Journal   (Followers: 8)
Fuel Cells Bulletin     Full-text available via subscription   (Followers: 9)
Fusion Engineering and Design     Hybrid Journal   (Followers: 6)
Fuzzy Information and Engineering     Open Access   (Followers: 2)
Fuzzy Sets and Systems     Hybrid Journal   (Followers: 3)
Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards     Hybrid Journal   (Followers: 8)
Géotechnique     Hybrid Journal   (Followers: 27)
Geothermics     Hybrid Journal   (Followers: 7)
Glass Technology - European Journal of Glass Science and Technology Part A     Full-text available via subscription   (Followers: 1)
Global Journal of Engineering Research     Full-text available via subscription  
Global Transitions Proceedings     Open Access  
GPS Solutions     Hybrid Journal   (Followers: 28)
Graphs and Combinatorics     Hybrid Journal   (Followers: 4)
Grass and Forage Science     Hybrid Journal   (Followers: 4)
Groundwater for Sustainable Development     Full-text available via subscription   (Followers: 5)
Heat Transfer - Asian Research     Hybrid Journal   (Followers: 11)
Heat Transfer Engineering     Hybrid Journal   (Followers: 36)
Heat Treatment and Surface Engineering     Open Access  
High Voltage     Open Access  
Himalayan Journal of Science and Technology     Open Access  
Historical Records of Australian Science     Hybrid Journal   (Followers: 2)
Human Behavior and Emerging Technologies     Hybrid Journal   (Followers: 1)
Human Factors in Ergonomics & Manufacturing     Hybrid Journal   (Followers: 12)
Human-Intelligent Systems Integration     Hybrid Journal  
I+D Revista de Investigaciones     Open Access  
IBM Journal of Research and Development     Hybrid Journal   (Followers: 16)
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 112)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 88)
IEEE Communications Magazine     Full-text available via subscription   (Followers: 140)
IEEE Embedded Systems Letters     Hybrid Journal   (Followers: 60)
IEEE Engineering Management Review     Full-text available via subscription   (Followers: 117)
IEEE Geoscience and Remote Sensing Letters     Hybrid Journal   (Followers: 151)
IEEE Geoscience and Remote Sensing Magazine     Hybrid Journal   (Followers: 6)
IEEE Industry Applications Magazine     Full-text available via subscription   (Followers: 82)
IEEE Instrumentation & Measurement Magazine     Hybrid Journal   (Followers: 148)
IEEE Journal of Biomedical and Health Informatics     Hybrid Journal   (Followers: 14)
IEEE Journal of Oceanic Engineering     Hybrid Journal   (Followers: 11)
IEEE Journal of Selected Topics in Quantum Electronics     Hybrid Journal   (Followers: 7)
IEEE Journal of Selected Topics in Signal Processing     Hybrid Journal   (Followers: 43)
IEEE Journal of Solid-State Circuits     Full-text available via subscription   (Followers: 24)
IEEE Journal on Selected Areas in Communications     Hybrid Journal   (Followers: 39)
IEEE Latin America Transactions     Full-text available via subscription   (Followers: 2)
IEEE Magnetics Letters     Hybrid Journal   (Followers: 7)
IEEE Microwave and Wireless Components Letters     Hybrid Journal   (Followers: 35)
IEEE Microwave Magazine     Full-text available via subscription   (Followers: 63)
IEEE Nanotechnology Magazine     Hybrid Journal   (Followers: 45)
IEEE Open Journal of Engineering in Medicine and Biology     Open Access   (Followers: 1)
IEEE Open Journal of Nanotechnology     Open Access   (Followers: 1)
IEEE Potentials     Full-text available via subscription   (Followers: 42)
IEEE Reviews in Biomedical Engineering     Hybrid Journal   (Followers: 19)
IEEE Signal Processing Letters     Hybrid Journal   (Followers: 60)
IEEE Solid-State Circuits Magazine     Hybrid Journal   (Followers: 11)
IEEE Spectrum     Full-text available via subscription   (Followers: 221)
IEEE Technology and Society Magazine     Full-text available via subscription   (Followers: 8)
IEEE Transactions on Advanced Packaging     Full-text available via subscription   (Followers: 8)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 79)
IEEE Transactions on Applied Superconductivity     Hybrid Journal   (Followers: 5)
IEEE Transactions on Automation Science and Engineering     Full-text available via subscription   (Followers: 13)
IEEE Transactions on Autonomous Mental Development     Hybrid Journal   (Followers: 8)
IEEE Transactions on Biomedical Engineering     Hybrid Journal   (Followers: 35)
IEEE Transactions on Broadcasting     Hybrid Journal   (Followers: 11)
IEEE Transactions on Circuits and Systems II: Express Briefs     Hybrid Journal   (Followers: 20)
IEEE Transactions on Components and Packaging Technologies     Full-text available via subscription   (Followers: 17)
IEEE Transactions on Control Systems Technology     Hybrid Journal   (Followers: 111)
IEEE Transactions on Education     Hybrid Journal   (Followers: 11)
IEEE Transactions on Electronics Packaging Manufacturing     Hybrid Journal   (Followers: 21)
IEEE Transactions on Energy Conversion     Hybrid Journal   (Followers: 16)
IEEE Transactions on Engineering Management     Hybrid Journal   (Followers: 74)

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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: 88  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1536-1225
Published by IEEE Homepage  [228 journals]
  • IEEE Antennas and Wireless Propagation Letters

    • Free pre-print version: Loading...

      Abstract: Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Triple-Band Dual-Polarized SIW Cavity-Backed Differential Slot Antenna

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      Authors: Gunjan Srivastava;Akhilesh Mohan;Amitabha Bhattacharya;
      Pages: 858 - 862
      Abstract: A differential triple-band dual-polarized cavity-backed substrate-integrated waveguide (SIW) slot antenna is presented in this letter. The hybrid TE130, TE320, and TE140 modes of the square SIW cavity are excited by differential feed for a triple-band realization. The proposed antenna exhibits dual-polarized radiations at 9.06, 11.86, and 14.23 GHz. An isolation better than 40 dB in all the three frequency bands between the differential ports is obtained. The proposed structure exhibits the differential gain of 5.4, 10.7, and 9.5 dBi at 9.06, 11.86, and 14.23 GHz, respectively. To validate the design approach, the proposed antenna is fabricated and its characteristics are measured.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • A Transmission Line Transition to Extend the Transmission-Line-Excited
           Magnetoelectric Dipole Antenna Array

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      Authors: Xuexuan Ruan;Kai Wang;Kai Xu Wang;
      Pages: 863 - 867
      Abstract: A differentially driven transmission-line-excited magnetoelectric dipole (ME-dipole) array antenna is designed for fifth-generation (5G) applications. It is derived from our previous work using a single-layered printed circuit board (PCB) with plated-through-hole technology. The proposed antenna is composed of a 2 × 4 ME-dipole array surrounded by a rectangular cavity. A pair of differential ports feed the antenna. Experiments show that the proposed antenna presents an impedance bandwidth of 26.8% from 55.3 to 72.4 GHz, a 3 dB gain bandwidth of 25% from 55.4 to 71.2 GHz, and a peak gain of 15.3 dBi at 62 GHz. Moreover, the proposed antenna retains all the salient features of the ME-dipole in symmetric radiation patterns and low cross-polarization and back radiation levels.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Dual-Band Aperture-Shared Fabry–Perot Cavity-Integrated Patch Antenna
           for Millimeter-Wave/Sub-6 GHz Communication Applications

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      Authors: Jianfeng Zhu;Yang Yang;Shaowei Liao;Shufang Li;Quan Xue;
      Pages: 868 - 872
      Abstract: This letter presents a dual-band antenna with a large frequency ratio of 11.7 (2.4 GHz/28 GHz) by integrating an mm-wave Fabry–Perot cavity (FPC) antenna into a sub-6 GHz patch antenna. The patch with periodic slots functions as both the 2.4 GHz radiator and the partially reflective surface (PRS) of the 28 GHz FPC antenna. By properly tuning the length of the periodic slot, the PRS's reflection can be easily adjusted. As the periodic slot's length and width operating at 28 GHz are much smaller than the wavelength at 2.4 GHz, periodic slot operating at 28 GHz have little impact on the radiation of the patch. Furthermore, because of the Fabry–Perot resonance, the antenna can have a peak gain reaching 15 dBi at 28 GHz band with an easy feeding structure. For demonstration, a prototype is fabricated and experimentally verified. Note that the frequency ratio is not limited to the proposed design (11.7 for demonstration). It can be easily adjusted based on the same principle.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Direction Finding Using a Single Antenna With Blade Modulation

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      Authors: Kai Ren;
      Pages: 873 - 877
      Abstract: A single top-hat antenna using blade modulation is presented for direction finding (DF). Unlike conventional DF techniques requiring an antenna array with multiple elements, the fixed single antenna is utilized to receive incoming signals. To enhance radiation pattern diversity and perform direction of arrival estimation, four rotating blades are placed around four corners of the antenna. The antenna is designed to operate at the frequency where the incoming wave is in resonance with the metallic blades. The incoming signals are recorded as blades rotating with an angle from 0$^circ $ to 180$^circ $. To validate the radiation pattern diversity at the resonant frequency and out of the operational frequency band, correlation coefficients of amplitude and phase of complex radiation patterns between the antennas with different blade rotation angles are investigated. DF accuracy in azimuth directions of the proposed single antenna with blade modulation is demonstrated by Cramer–Rao bound using the complex radiation patterns at different frequencies.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Broadband Radar Cross Section Reduction Binary Metasurface With a
           High-Efficiency Intraband Transmission Window

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      Authors: Yu-Feng Fu;Jiang-Dong Ji;Ying-Jie Wang;Fang-Kun Zhou;Chen Wang;Ping Chen;
      Pages: 878 - 882
      Abstract: In this letter, a broadband radar cross section (RCS) reduction binary metasurface with a high-efficiency intraband transmission window is proposed and implemented based on multilayered elements combining the Jerusalem cross and cross-slot patterns. Electromagnetic responses of such structures are investigated by the equivalent circuit method. The results indicate that the metasurface consisting of elements with two types of Jerusalem crosses can invoke diffused scattering to reduce the RCS of metallic targets. Meanwhile, the metasurface has a high-efficiency transmission window since the bandpass cross-slot pattern is deployed here. The simulation results indicate that the metasurface can achieve a −10 dB RCS reduction from 3.5 to 11.5 GHz and transmission with an insertion loss of 0.72 dB at 8.4 GHz. The performances of the proposed metasurface are verified experimentally. Our design may find potential applications in the low-RCS antenna or the stealth radome for wireless facilities.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Wideband Open-Ended Ridge Gap Waveguide Antenna Elements for 1-D and 2-D
           Wide-Angle Scanning Phased Arrays at 100 GHz

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      Authors: Yingqi Zhang;Artem R. Vilenskiy;Marianna V. Ivashina;
      Pages: 883 - 887
      Abstract: A new antenna element type based on the open-ended ridge gap waveguide (RGW) is proposed for phased array applications. This element type is of a particular interest at high millimeter-wave frequencies ($geq$ 100 GHz) owing to a contactless design alleviating active beam-steering electronic integration. The key challenge addressed here is a realization of a wide fractional bandwidth and a wide scan range with high radiation efficiency. We demonstrate a relatively simple wideband impedance matching network comprised of an aperture stepped ridge segment and a single-pin RGW section. Furthermore, the $E$- and $H$-plane grooves are added that effectively suppress antenna elements’ mutual coupling. Results demonstrate a wide-angle beam steering ($geq text{50}^circ$) over $geq {20%}$ fractional bandwidth at the $W$-band with $geq {89%}$ radiation efficiency that significantly outperforms the existing solutions at these frequencies. An experimental prototype of a 1 × 19 $W$-band array validates the proposed design concept through the embedded element pattern measurements.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • The Save-the-Rhino Antenna: A Horn-Mounted Wire-Based Monopole

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      Authors: Guy A. E. Vandenbosch;Jiahao Zhang;Sen Yan;Vladimir Volski;
      Pages: 888 - 892
      Abstract: A new antenna topology dedicated to being mounted on the horn of an adult rhino is proposed. The curved topology of the horn, the material characteristics of the horn material, mechanical aspects when being mounted, and the typical behavior of rhinos in the wild are taken into account in the design process. The results are extremely promising. It is illustrated that this antenna is much better than antennas already operational in tracking networks targeting rhinos. In this way, it may contribute to the rescue of this endangered species.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Fast Prediction of Quasi-Periodic Array Using Dynamical Graph
           Convolutional Neural Networks

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      Authors: Wei Xiang;Zhe Zhang;Xiaolu Yang;Zhenguo Liu;Wu Yang;Jiaqi Li;Wenming Zheng;Weibing Lu;
      Pages: 893 - 897
      Abstract: In this letter, a novel approach based on dynamic graph convolutional neural networks (DGCNNs) is proposed to analyze the quasi-periodic array consisting of the cells with different geometric parameters. Each vertex node in a graph represents a cell in quasi-periodic array and the features of each vertex node are determined by the geometric parameters of the corresponding cell. The connections in graph are initialized and dynamically updated to learn the mutual coupling among cells. DGCNNs are constructed and trained such that the neural networks can obtain the relationships among cells. The trained DGCNNs can predict the S-parameters of a quasi-periodic array and the numerical experiments demonstrate the accuracy and efficiency of our method.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Vertically Polarized 360° Azimuth Scanning Array

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      Authors: Jiadong Hu;Yue Li;Zhijun Zhang;
      Pages: 898 - 902
      Abstract: In this letter, a vertically polarized 360° azimuth scanning phased array based on a wide beamwidth element is proposed. The proposed array consists of two back-to-back linear arrays. The broadside and endfire scanning modes are combined to realize 360° beam scanning in the azimuth plane (H-plane). A 2 × 8 array working at 3 GHz has been fabricated and measured. The array scans from −180° to 180° in the H-plane with the measured peak gain of 10.8 dBi, the measured gain fluctuation less than 2 dB. The total height of the proposed array is 0.32 λ, showing its potentials in aircraft-based application.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Enhanced Path Loss Model by Image-Based Environmental Characterization

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      Authors: Lina Wu;Danping He;Bo Ai;Jian Wang;Dongliang Liu;Fusheng Zhu;
      Pages: 903 - 907
      Abstract: Accurate path loss (PL) models are critical for the design and optimization of wireless communication systems. The selection between empirical models and deterministic models are usually a tradeoff between accuracy and efficiency. In this letter, a novel environmental characterization method is defined by considering clutter information in the vector-based and image-based structures. Three PL models are proposed with different artificial neural network (ANN) architectures and two environmental characterizations. Comparative analysis shows that an image-based environmental characterization, which can reduce the influence of interference types, is better than a vector-based characterization. The combination of an image-based environmental characterization method and ANNs can enhance PL prediction in both accuracy and efficiency.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Dimension-Reduced Optimization for Uniform Near-Field Synthesis of
           Irregular Arrays

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      Authors: Shang Guo;Deshuang Zhao;Bing-Zhong Wang;
      Pages: 908 - 912
      Abstract: A novel optimization method of a significantly reduced optimizing dimension is presented to quickly synthesize the uniform near fields of irregular arrays. In this method, the element excitations of the array are no longer executed as the direct optimization parameters. Instead, we build a new search space made of the smooth reference masks (SRMs) and perform the optimization directly based on the parameters of the SRMs rather than the element excitations. To obtain the desired uniform near fields, only two critical parameters of the SRMs need to be optimized. Comparing the direct element-excitation optimizations, the proposed method significantly reduces the optimizing dimension and makes the synthesis much more efficient and faster. Several numerical examples and their comparisons with the well-developed convex optimization algorithm were presented. The results demonstrate the effectiveness and the significant reduction of time consumption of the proposed method.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • A Wideband Circularly Polarized Folded Reflectarray Antenna With Linearly
           Polarized Feed

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      Authors: Pan-Pan Zhang;Xi-Cheng Zhu;Yun Hu;Zhang-Cheng Hao;Guo-Qing Luo;
      Pages: 913 - 917
      Abstract: The design and implementation of a wideband circularly polarized folded reflectarray antenna (CPFRA) with a linearly polarized (LP) feed antenna is presented in this letter. The subreflector of the proposed CPFRA is in the form of a polarization-sensitive frequency selective surface (FSS) based on the antenna-filter-antenna (AFA) technology other than the traditional polarizing grid. The AFA FSS is designed to convert the LP incident wave into circularly polarized (CP) wave within its passband and reflect the orthogonal LP incident wave over a wide frequency band. Futhermore, the sequential rotation technique is applied in the design of main reflectarray and subreflector to greatly enhance the axial ratio (AR) bandwidth of the CPFRA. An antenna prototype has been fabricated and measured at X-band. Good agreement between the measured and simulated results has been achieved by the wideband CPFRA. The measured results show that the maximum antenna gain reaches up to 28.2 dBic at 10.2 GHz with its aperture efficiency of 43.3%. The 3 dB gain frequency band is from 9.1 to 10.6 GHz and the 3 dB AR frequency band from 8.7 to 11.2 GHz, respectively.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • A Fractal-Based Time-Modulated Multiband Linear Array for Interband
           Communication

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      Authors: Ananya Mukherjee;Sujit K. Mandal;Rowdra Ghatak;
      Pages: 918 - 922
      Abstract: A novel method of utilizing the repetitive self-similar propertyof the cantor set fractal (CSF) pattern in synthesizing a time-modulated linear array (TMLA) with multiband characteristics, applicable for interband communication, is proposed. The fractal pattern of different growth stages is used to constitute subarrays (SAs) and each group of the subarrayed elements is periodically modulated via a single radio frequency (RF) switch. A closed-form array factor (AF) expression of the proposed CSF–TMLA is derived, and through representative results, it is shown that a Pth stage CSF-TMLA is eligible to be functional at “P” intercommunication bands with power patterns of the same sidelobe level. It is further investigated that the number of RF switches and, hence, the unknown optimization variables essentially entailed to synthesize the array are drastically reduced.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Antenna Diagnostics Based on Infinitesimal Dipole Modeling With Limited
           Measurement on Antenna Aperture

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      Authors: Ju-Ik Oh;Sung Jun Yang;Sol Kim;Jong-Won Yu;Young Dam Kim;
      Pages: 923 - 927
      Abstract: This letter presents an antennadiagnosis method using infinitesimal dipole modeling. For antenna diagnosis, it is important to estimate the current distribution of the antenna aperture. By using the measured near-field data of the antenna, the infinitesimal dipole current distribution that can generate the same near-field measurement result is extracted. This current distribution can be considered as a back-projection image on the antenna aperture. Using the infinitesimal dipole modeling, accurate antenna diagnosis is possible even by using only the measured near-field which is limited over the antenna aperture. We compared the results of the conventional antenna diagnosis method based on Fourier transform and the proposed method for the near-field measurement results of the standard gain horn antenna. Although the limited near-field measurement over the antenna aperture, the back-projection image for the antenna diagnosis of the proposed method has a very high resolution.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Compact High-Isolated MIMO Antenna Module With Chip Capacitive Decoupler
           for 5G Mobile Terminals

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      Authors: Yang Ye;Xing Zhao;Junyin Wang;
      Pages: 928 - 932
      Abstract: In this letter, a compact high-isolated multiple-input–multiple-output (MIMO) antenna module based on a chip capacitive decoupler is proposed for the fifth-generation (5G) smartphones. The antenna module consists of two feeding ports, radiating metal strips, and a chip capacitive decoupler within a compact size of 16 × 6 mm2. In this design, two L-shaped metal strips are used as distributed capacitors to compress the size of the module. Meanwhile, a chip capacitive decoupler is added to improve isolation between the two feeding ports, which is realized with an analysis of common and differential modes. In addition, spiral slots are used to adjust the isolation between the modules. A prototype MIMO antenna with four such dual-port antenna modules was tested in the 3.5 GHz band. The measured –6 dB bandwidths of the two ports are 310 MHz (3.42–3.73 GHz) and 360 MHz (3.33–3.69 GHz), respectively, and the isolation is 24 dB at 3.5 GHz. The measured efficiencies are 60.5% and 52.7% at 3.5 GHz. The compact MIMO antenna module with high-isolation property provides a hopeful solution for the 5G mobile terminals.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Wideband Simulations of Periodic Structures by the Hybrid Spectral
           FDTD/TD-VFz Method

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      Authors: Samuel Gaucher;Christophe Guiffaut;Alain Reineix;Olivier Cessenat;Geneviève Mazé-Merceur;
      Pages: 933 - 937
      Abstract: The spectral finite-difference time-domain method is combined with the discrete-time time-domain vector fitting (TD-VFz) algorithm to analyze three-dimensional (3-D) periodic structures excited by oblique incident plane waves over a wide frequency band. The time signal reconstruction with TD-VFz produces an untruncated response over an infinite time window allowing an accurate spectral result, especially near the cutoff frequency separating the spectrum propagating wave region of the evanescent wave region.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Near-Field Effects on Micrometer Accurate Ranging With Ultra-Wideband
           mmWave Radar

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      Authors: Lukas Piotrowsky;Jan Barowski;Nils Pohl;
      Pages: 938 - 942
      Abstract: We investigated near-field effects on free-space ranging with ultra-wideband millimeter-wave (mmWave) radar. In this application, one often assumes far-field conditions. However, with increasing requirements of accuracy, far-field assumptions are not satisfying. The radar measurements are affected by phase variations, leading to erroneous distance estimates. To simulate and approximate these effects, we propose computational methods by means of physical optics. They were validated using a state-of-the-art frequency-modulated continuous-wave radar sensor. Sophisticated experiments show good agreement; thus, in practice, the methods can be used to correct distance estimates to achieve micron accuracy without extensive calibration in advance.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Platform-Tolerant Nested-Slot RFID Tag Antenna Based on Jigsaw-Shaped
           Metasurface

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      Authors: Qi Liu;Shuomin Zhong;Yufeng Yu;Wen-Sheng Zhao;Gaofeng Wang;
      Pages: 943 - 947
      Abstract: A novel low-profile (
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • First Sidelobe Analysis of Spatial Spectrum for Distributed Dual mmWave
           Radars

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      Authors: Ruitao Liu;Xianxiang Yu;Qinghui Lu;Wenqiang Wei;Guolong Cui;
      Pages: 948 - 952
      Abstract: This letter considers a distributed cascade of two millimeter-wave (mmWave) radars to achieve a large virtual aperture for high-resolution angle measurement. In order to explore the high sidelobe problem caused by distributed radars, we derive the general Bartlett spatial spectrum expression of the virtual array. Furthermore, we introduce four cases to describe the relationship between the radar spacing, the number of transmitters/receivers, and the sidelobe position of the spatial spectrum. Finally, numerical simulation and experiment examples are provided to verify the effectiveness of the analysis.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Wideband VHF/UHF Wing Conformal Vertical Polarized Omnidirectional
           Antenna

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      Authors: Xi Chen;Hao Wu;Guang Fu;
      Pages: 953 - 957
      Abstract: This letter proposes a novel wideband wing conformal vertical polarized omnidirectional antenna for the very high frequency/ultrahigh frequency band. The antenna adopts symmetrical radiation and feed structures to obtain quasi-omnidirectional radiation. To be conformal with the ultrathin body of the wing, this construction is realized using double-layer flexible metal films that cover the surface of the wing. Moreover, there are several symmetric grooves on the upper metal film that are beneficial to improve the efficiency of radiation. The upper and lower metal films are connected by two shorting plates with same exponential gradual outline for vertical polarization and wideband potential. The ultrawide operating band can be realized by loading resistors and inductors. A conformal prototype of the antenna was fabricated and validated. The wing thickness determines the profile, which is only 0.013 λL, where λL is the wavelength at the lowest operating frequency. Its acquired bandwidth ranges from 100 to 600 MHz; high radiation efficiency and vertically polarized quasi-omnidirectional characters are also obtained in this band.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Parameter Inversion by a Modified Reflected Signal Reconstruction Method
           for Thin-Layered Media

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      Authors: Yixuan Li;Xiaopeng Yang;Tian Lan;Renjie Liu;Xiaodong Qu;
      Pages: 958 - 962
      Abstract: Parameter estimation of layered media is an important application of ground penetrating radar (GPR). However, in the case of thin-layer detection, the limitation of GPR vertical resolution can lead to overlapping reflected signals, which seriously deteriorates the detection results. To solve this problem, a modified reflected signal reconstruction method based on reflected signal reconstruction is proposed in this letter. First, a forward model of the GPR reflected signal is constructed using the generalized reflection coefficient definition. Then, the parameter inversion is transformed into an optimization problem. The residue cost function is defined as the error square between the model and the actual reflected signal, which is minimized by using genetic algorithm. Furthermore, the generalized reflection coefficient spectrum is feasible to estimate the parameters of each layer as the initial values of the parameters required by the algorithm, thus improving the accuracy and convergence speed of the algorithm. Numerical, experimental, and field tests demonstrate that the method has a high time resolution and antinoise capability in the inversion of layered media parameters.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Observations of Anomalous Over-the-Horizon Propagation in the Evaporation
           Duct Induced by Typhoon Kompasu (202118)

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      Authors: Shuwen Wang;Kunde Yang;Yang Shi;Fan Yang;
      Pages: 963 - 967
      Abstract: Evaporation ducts, which form as a result of evaporation from the ocean, have a significant impact on electromagnetic (EM) propagation in coastal and marine environments. Theoretically, typhoons would substantially increase the mass, momentum, and heat exchanges at the air-sea interface and thus inevitably influence these EM propagation environments, including the duct conditions and propagation boundary conditions. However, the effects of typhoons on EM propagation have seldom been reported. In this study, anomalous propagation in the evaporation duct induced by Typhoon Kompasu (202118) was recorded by using an EM propagation system and automatic weather station. The length of the propagation link was 53 km, which was beyond the horizon. The evaporation duct's impact on EM propagation during Typhoon Kompasu was studied based on model simulation results. Propagation far beyond the horizon indicated that ducting was present during the typhoon passage. Furthermore, the approaching of the typhoon caused a decrease in path loss of about 20 dB. This was because the abnormal marine meteorological conditions induced by typhoons result in a high evaporation duct, which leads to a small path loss for EM propagation.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Low Sidelobe Orbital Angular Momentum Vortex Beams Based on Modified
           Bayliss Synthesis Method for Circular Array

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      Authors: Na Kou;Shixing Yu;
      Pages: 968 - 972
      Abstract: Electromagnetic orbital angular momentum (OAM) vortex beam patterns generated by conventional methods are always of high sidelobe level, which severely limits its application. Considering the sidelobe suppression abilities of Bayliss synthesis method for difference beams, we present a modified Bayliss synthesis procedure to obtain low sidelobe OAM vortex beams. The Bayliss synthesis method cannot suppress the sidelobe level of difference pattern to the desired value when the element number of linear array is relatively small. By modifying the original zero locations that need to be removed in Bayliss pattern, we can further suppress the sidelobe level of difference pattern. This can be called the modified Bayliss pattern. Finally, by expanding the proposed synthesis method from linear source to circular array, theoretical results show that sidelobe levels of OAM beams can be suppressed to less than −30 dB when OAM mode number varies from l = 1 to l = 10. The proposed low sidelobe OAM vortex beam can be applied in antijamming communications of near-field in the future.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Transient Analysis Method for Plasmonic Devices by PMCHWT With Fast
           Inverse Laplace Transform

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      Authors: Seiya Kishimoto;Shao Ying Huang;Yoshito Ashizawa;Katsuji Nakagawa;Shinichiro Ohnuki;Weng Cho Chew;
      Pages: 973 - 977
      Abstract: The transient analysis of electromagnetic problems is important in the designing of plasmonic devices. It is useful for clarifying physical phenomena with extremely short timescales, because transient response affects the device performance. A time-domain computational technique is proposed for the transient analysis of electromagnetic problems with nanostructures. Our method is based on boundary integral equations in the complex frequency domain and fast inverse Laplace transforms. The advantage of our method is that the objects can be modeled by surface structure, dispersive media can be easily considered, computational error analysis is simple, and the electromagnetic field at the desired observation time can be obtained.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Multiobject Design of a 3-D-Printed All-Dielectric Lens Antenna by an
           Automatic Synthesis Algorithm

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      Authors: Yan-Fang Liu;Lin Peng;Chen Wang;Xue-Mei Zheng;Qian-Kun Xu;Hao-Kai Jia;Cheng-Li Ruan;Si-Min Li;
      Pages: 978 - 982
      Abstract: Multiperformance indices of an E-band three-dimensional (3-D)-printed all-dielectric lens antenna are fulfilled by an automatic synthesis algorithm. By hybridizing particle swarm optimization and genetic algorithm optimization, the algorithm possesses the advantages of fast optimization and avoiding of local optimum. Multiobjective subfunctions are defined to realize multiperformance indices, and the objective subfunctions are customized to make the optimization process more efficient. As the all-dielectric lens is optimized, the source horn is included to direct acquire the performance indices (|S11|, axial ratio, and gain), which makes the optimization process efficient and accurate. Moreover, the optimization process is automatic as the structure modeling and sizing are performed automatically. The proposed lens antenna has good S11, axial ratio, and gain performances in the 60–90 GHz band, which shows that the algorithm is a powerful method for multiple goals.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • A Blind Adaptive Focused Antenna Array for the Unknown Target in Lossy
           Medium

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      Authors: Peng Gao;Shen-Yun Wang;Wen Geyi;
      Pages: 983 - 987
      Abstract: This letter presents a novel approach to achieve blind focusing of the electric field radiated by an antenna array on a target that is randomly distributed in lossy medium. The idea is to introduce a test receiving antenna centrally located within the antenna array and to find the excitation distribution of the antenna array by using the sensed scattering parameters between the transmitting array and the test receiving antenna. The excitation distribution of the transmitting array is calculated by using the method of maximum power transmission efficiency. An antenna array consisting of 5 × 5 rectangular microstrip patches loaded with colza oil medium is fabricated to demonstrate the blind focusing scheme with the target being a copper block that is immersed in the oil medium. The results indicate that the transmitting array can adaptively focus the radiated electric field on the copper block once the scattering parameters are sensed, without requiring any a priori knowledge of the geometry and of the electric properties of the target, as well as of its spatial position with respect to the antenna array.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Circularly Polarized Antenna Array With Suppressed Sidelobes for
           Electronic Toll Collection

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      Authors: Yan Dong;Xiao Cai;Geyi Wen;
      Pages: 988 - 992
      Abstract: In this letter, a 4×4 circularly polarized antenna array with suppressed sidelobes for electronic toll collection applications is proposed. The antenna array operates at 5.8 GHz and is designed based on the weighted constrained method of the maximum power transmission efficiency (WCMMPTE). Different constraints to control the polarization and sidelobe levels are simultaneously introduced to realize the desired polarizations and sidelobe levels. While the optimized distribution of excitations for the 4×4 antenna array is first obtained analytically by the WCMMPTE, a few elements with negligible exciting amplitudes are then removed to reduce the array size to yield a 12-element array together with a feeding network which are fabricated and tested. The measured results indicate that the fabricated array has a left-hand circular polarization gain of 15.3 dBi with sidelobe levels below –30 dB and half-power beamwidths of 30° in both ϕ = 0° and ϕ = 90° planes, which meet the requirements of ETC system. Moreover, a 3 dB axial ratio bandwidth of 720 MHz and a low axial ratio of 0.3 dB at 5.8 GHz have been achieved, which demonstrate a good circular polarization performance.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Experimental Demonstration of Test Cap Design for Space Transponder
           Applications

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      Authors: Khaldoun Alkhalifeh;Václav Valenta;Christophe Craeye;
      Pages: 993 - 996
      Abstract: Antenna test caps allow the testing of transmit and receive functionality of complete end-to-end radio frequency (RF) space systems in flight configuration outside anechoic environment. The test caps are made of two off-centered cylinders. The upper cylinder contains a probe, corresponding port, as well as a tuning screw. The lower cylinder contains absorbing material, the antenna under test. A full design and its experimental validation are demonstrated for a Martian X-band radio science payload.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • A Transmissive Frequency-Reconfigurable Cross-Polarization Conversion
           Surface

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      Authors: Peng Fei;Weihua Guo;Wei Hu;Qi Zheng;Xin Wen;Xing Chen;Guy A. E. Vandenbosch;
      Pages: 997 - 1001
      Abstract: A transmissive frequency-reconfigurable cross-pola- rization conversion surface is presented. First, two static cross-polarization conversion unit cells are proposed. Results indicate that they are both capable of transforming incoming linearly polarized waves into their cross-polarized counterparts effectively, but at different operating frequencies. Second, PIN diodes are employed to construct an active unit cell, imitating the behavior of each static unit cell, as the PIN diodes are on or off, respectively. Finally, a prototype containing 10 × 10 unit cells is designed, manufactured, and measured. Measurements show that with the PIN diodes in off or on state, a switchable cross-polarization converting band around 4.17 and 6.73 GHz is achieved, validating the proposed concept.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • A Target Deblurring Method for Frequency Diverse Array Imaging

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      Authors: Kefei Liao;Jifa Shen;Shan Ouyang;Qiaoying Yu;
      Pages: 1002 - 1006
      Abstract: The frequency diversity array (FDA) is subject to its own property, which will cause the problem of target blurring in imaging. The existing FDA deblurring target imaging method generally adopts the design of nonlinear frequency increments, but it also brings new problems associated with sidelobe increases. Aiming at the problem of frequency diversity array image deblurring, this letter proposes an FDA deblurring target imaging method. Starting from the mechanism through which the blur is caused by the mutual influence of frequency increments, a mathematical model of image domain blur is established. A deconvolution method is proposed to achieve high-quality imaging without blur under arbitrary frequency increments of FDA. What`s more, a low-error imaging method based on ripple transfer is proposed to deal with the problem of error accumulation in deblurring. Finally, the effectiveness of the algorithm is verified by experimental simulation.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • A Frequency-Reconfigurable Planar Slot Antenna Using S-PIN Diode

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      Authors: Xiangyu Jin;Shaobin Liu;Yuning Yang;Yonggang Zhou;
      Pages: 1007 - 1011
      Abstract: A novel frequency-reconfigurable solid-state plasma chip antenna based on plane slot is proposed. The radiation slot of the antenna is embedded with a surface-PIN (S-PIN) diode and fed by a microstrip line through electromagnetic coupling. The state of the S-PIN diode can be switched by applying a forward bias voltage to realize the reconfigurable radiation slot of the antenna. The structure parameters of the S-PIN diode have been optimized. The overall size of the silicon-on-insulator (SOI) substrate is controlled at 20 × 10 × 0.35 mm. A prototype of the proposed antenna is fabricated and measured. The measured results show that the proposed antenna can realize cross-band frequency switching from 6.8 to 15.5 GHz. Meanwhile, the normalized radiation patterns show prominent reconstruction characteristics as the bias voltage changes. The proposed solid-state plasma antenna offers high integration compared with traditional reconfigurable antennas. The experiment results validate the applicability of the S-PIN diodes to manufacture reconfigurable planar slot antennas.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Direct Metal Laser Sintering Conformal Waveguide Array Antenna for
           Millimeter-Wave 5G Communications

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      Authors: Pablo Sanchez-Olivares;Eduardo Garcia-Marin;Jose Luis Masa-Campos;
      Pages: 1012 - 1016
      Abstract: An omnidirectional conformal array antenna has been implemented in air-filled waveguide technology for the 37–40 GHz band. The input port of the antenna is a standard WR28 rectangular waveguide. The TE10 mode excited in the rectangular waveguide is used to generate the TE01 mode inside a circular waveguide by means of a TE10–TE01 mode converter. The circular waveguide section is progressively widened, forming a radial waveguide structure, where the TE01 mode propagates radially through several radiating apertures. Due to the rotational symmetry of the structure, an omnidirectional radiating performance with low ripple can be achieved. This structure has been three-dimentional (3-D) manufactured using the direct metal laser sintering technology. A good agreement between simulations and measurements has been found. A reflection coefficient of below −15 dB, a low-ripple omnidirectional performance in a conical cut plane, a low cross-polar radiation, and a total efficiency higher than 83% are obtained. This conformal antenna design is proposed for fifth generation (5G) New Radio indoor applications.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • An Ultralong-Range, Wideband Planar UHF RFID Tag With Two Split Arcs

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      Authors: Weijia Meng;Yongtao Ma;Chenglong Tian;Dianfei Su;
      Pages: 1017 - 1021
      Abstract: A wideband planar passive UHF radio frequency identification (RFID) tag with an ultralong range is proposed in this letter. It is electrically small with a compact footprint of 59.6 mm × 33.3 mm (0.18 $lambda$ × 0.10 $lambda$). The tag is designed based on a T-matching network, and two split arcs are introduced to adjust the resistance and reactance of the tag for the first time. Due to the almost perfect conjugate matching, the power transmission coefficient of the proposed tag reaches 99.63$%$. Finally, it has been fabricated and tested. The measured read range of the tag is greater than 6.2 m within the whole UHF-RFID band (860–960 MHz) with a maximum value of 21.3 m at 910 MHz (with 4 W effective isotropic radiated power).
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • High-Gain and Low-Loss Dual-Polarized Antenna Array With Reduced Sidelobe
           Level Based on Gap Waveguide at 28 GHz

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      Authors: Juqing Ran;Cheng Jin;Pengyu Zhang;Weimin Wang;Yongle Wu;
      Pages: 1022 - 1026
      Abstract: In this letter, a 16×16-element dual-polarized antenna array with a reduced sidelobe level is proposed at 28 GHz for fifth-generation (5G) communication systems. The dual linear polarization operation is carried out through cross-shaped waveguide slots and multilayer feeding networks. Low-loss gap waveguide technology and Taylor distribution are applied in the feeding networks. A ridge unequal power divider with flexible power ratio and phase difference is devised and applied in the gap waveguide feeding network to reduce the complexity of unequal power structural design. A prototype of the proposed dual-polarized antenna array is manufactured by milling technology. Measured results show that the realized gains are higher than 28 dBi over the operating frequency band of 27.4–28.6 GHz. Moreover, the sidelobe level is lower than −18.5 dB for the y-direction polarization and −19.5 dB for the x-direction polarization.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • An Interlaced Grid Dual-Band Dual-Polarized Bandpass FSS With a Large Band
           Ratio

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      Authors: Peng Jiang;Wen Jiang;Wei Hu;Shuxi Gong;
      Pages: 1027 - 1031
      Abstract: Based on an interlaced grid arrangement, a dual-band dual-polarized bandpass frequency selective structure (FSS) with a large band ratio (BR) is proposed in this letter. The FSS is assembled from vertical layers arranged along x- and y-directions, and the vertical layers arranged along the two orthogonal directions are polarization independent. The grating structures printed on the vertical layers form a higher frequency passband, and by having additional wire-grid polarizers with a high-pass response, a lower frequency passband is formed. The proposed interlaced grid FSS is a combination of two square grid FSSs. Since the distance between adjacent vertical layers is smaller than that of the square grid FSS, the proposed FSS has a wider bandstop response to achieve the design of a large BR. The measured results show that for both TE and TM polarizations, the center frequencies of the two passbands are 2.5 GHz and 15.5 GHz, respectively, with a corresponding BR of 6.2.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • A Compact Dual-Mirror Design of Quasi-Optical Mode Converter for Gyrotron
           Application

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      Authors: Ming Jin;Xiang Li;Dong Xia;Yichi Zhang;Yizhang Zhu;Ming Bai;
      Pages: 1032 - 1036
      Abstract: The quasi-optical mode converter (QOMC) for high-power fusion gyrotron is a typical beam transformation and shaping device in near-field region. In this letter, the authors report their progress in designing a compact QOMC with only two reflecting mirrors. For achieving the high-efficiency conversion comparable to conventional multimirror converters, the authors exercise modification and optimization on the first mirror based on the classic quasi-elliptical design. It is shown that the optimized first mirror can fulfill multifunctions that have to be achieved by a chain of mirrors in conventional designs. Numerical results show the effectiveness of the optimization, which can be revealed by the achieved 95.97% Gaussian content in the output beam with power transmission efficiency of 99.0%.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Design Approach for a Dual-Band Circularly Polarized Slot Antenna With
           Flexible Frequency Ratio and Similar In-Band Gain

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      Authors: Yanhui Xu;Lei Zhu;Neng-Wu Liu;
      Pages: 1037 - 1041
      Abstract: This letter presents an effective approach to design a dual-band circularly polarized (CP) slot antenna with flexible frequency ratio (FFR) and similar in-band gain under the 0.5 $lambda$- and $itlambda$-mode radiation. Initially, a CP slot antenna is realized in virtue of two orthogonal slot radiators. Then, by folding both slot radiators at a 1/4 length position from the short-circuited terminal, a CP slot antenna operating at two distinct bands is successfully realized based on the 0.5 $itlambda$- and $itlambda$-mode, where stable gain with similar level for the dual working bands is achieved. After that, two pairs of slot stubs are properly introduced to effectively reallocate the higher band based on the $itlambda$-mode, thus acquiring for a wide frequency ratio ranging from 1.85 to 1.26. Finally, for experimental validation purposes, two specific CP slot antennas with distinctive frequency ratios of 1.85 and 1.26 are implemented and tested. A similar-level gain within their dual operating bands can be achieved as another merit in addition to the FFR.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Effect of Vertical Downdraft on Rain Attenuation Modeling Over an
           Earth-Space Path

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      Authors: Gargi Rakshit;Animesh Maitra;
      Pages: 1042 - 1045
      Abstract: The impact of vertical downdraft on rain attenuation estimation from rain rate measurements has been studied. The rain rate (R) and specific attenuation (γ) are derived from rain drop size distributions (DSD) by considering the widely accepted Gunn–Kinzer (G-K) relationship between drop size and drop fall velocity that is valid for stagnant air. In the real atmosphere, drops are carried with the vertical wind draft, and the actual fall velocity of the raindrops deviates from the G–K formulation. The ITU-R estimated rain attenuation values, based on DSDs, which are mostly valid for temperate regions, can deviate from actual rain attenuation measurements in tropical regions, especially at higher rain rates when downdraft is prominent. The present study uses disdrometer measurements of DSD, optical rain gauge measurements of rain rates, and Ku-band rain attenuation data over an earth-space path at a tropical location Kolkata (22°34′ N, 88°29′ E) to show that vertical downdrafts impact the rain attenuation estimation from rain rate measurements. At the present location, an overall representative vertical downdraft of 2 m/s needs to be considered to match the experimental attenuation measurements with the estimated values using the modified γ–R relationship in the ITU-R model.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Designing and Modeling of a Dual-Band Rectenna With Compact Dielectric
           Resonator Antenna

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      Authors: Lei Guo;Xuwang Li;Wenjian Sun;Wenwen Yang;Yangping Zhao;Ke Wu;
      Pages: 1046 - 1050
      Abstract: In this letter, a compact dual-band rectenna is modeled and developed for low radio frequency (RF) power harvesting. The proposed theoretical model can provide a comprehensive analysis of the rectenna, including the power conversion efficiency (PCE) of the diode, matching efficiency of the rectifier, and total PCE of the rectenna. In the rectenna design, a very compact omnidirectional dielectric resonator antenna (DRA) is proposed with a broad bandwidth exceeding 40%. Meanwhile, a dual-band rectifier is designed based on a single branch in the low-power range with bandwidths covering the two fifth-generation (5G) frequency bands in China (2.515–2.675 and 3.4–3.6 GHz). It was found that the theoretical model can show a high accuracy with the calculation error within 5% in analyzing the dual-band rectifier. The DRA and the dual-band rectifier are integrated to form a compact dual-band rectenna. It shows a higher PCE than those of the existing multiband designs working at similar low-power levels. It is hoped to be implemented in 5G-enabled Internet of Things (IoT) applications for powering wireless sensor nodes.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Wearable Wideband Circularly Polarized Array Antenna for Off-Body
           Applications

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      Authors: Yujun Chen;Xiongying Liu;Yi Fan;Hongcai Yang;
      Pages: 1051 - 1055
      Abstract: A wideband circularlypolarized (CP) wearable antenna for 5 GHz (5.15–5.825 GHz) wireless body area network is presented and analyzed. The emphasis of this work is on the additional resonance generated by the mutual coupling of a 2×2 compact patch array. As the proposed antenna is fed by a sequential-phase feeding network, the resonance can be used to achieve unidirectional radiation with improved CP bandwidth. To alleviate the loading effects of the human body, a modified strip feedline, comprising two pairs of arc-shaped slots cut on the bottom ground, is introduced. Moreover, the adoption of textiles as substrate and conductor provides flexibility and conformability, allowing the antenna to be integrated with garments. The prototype with the dimensions of 40 mm × 40 mm × 4 mm (0.73 λ0 × 0.73 λ0 × 0.07 λ0) was fabricated. The measured results indicate that a wide impedance bandwidth of 43% (4.25–6.63 GHz), a half-power beamwidth of 60°, and a 3 dB AR bandwidth of 34% (4.71–6.67 GHz) are achieved. Furthermore, the antenna performance is proved to be stable under structural deformation and human body loading. Finally, transmission losses and link budgets are evaluated, enabling the antenna to be a robust solution for off-body communications.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Efficient Vector Interpolation Method Based on Lebedev Quadrature for
           MLFMA

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      Authors: Xiao-Yang He;De-Hua Kong;Wen-Wei Zhang;Ming-Yao Xia;
      Pages: 1056 - 1059
      Abstract: In this letter, an efficient vector interpolation method based on Lebedev quadrature to accelerate the matrix-vector multiplications in far-field regions for the multilevel fast multipole algorithm (MLFMA) is presented. This approach avoids the singularity on sphere poles in the traditional interpolation method based on Gaussian quadrature and maintains the same accuracy without increasing computational costs. As a consequence, both memory consumption and processing time can be reduced considerably, providing a viable alternative to solve large-scale electromagnetic scattering problems using MLFMA.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • Dual-Polarized Nonuniform Fabry–Pérot Cavity Antenna With Flat-Topped
           Radiation Pattern

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      Authors: Xi Ran;Xiao-Hua Wang;Yi-Di Hu;Shi-Wei Qu;Bing-Zhong Wang;
      Pages: 1060 - 1064
      Abstract: A method to realize the flat-topped radiation pattern of Fabry–Pérot cavity antenna is proposed based on the ray-tracing model. In the design, a nonuniform partially reflective surface of dielectric substrate is proposed to reduce the sidelobe level and get a fast roll-off in the operating frequency band. Besides, a dumb source array is added around the dual-polarized feed array to minimize the disparity of beamwidth between E- and H-plane. The antenna was calculated with the proposed method, simulated by the full-wave simulation, and validated by the experiment. Compared with the traditional array synthesis method, there is no need to design a complex feed network because each coaxial port is fed equally in phase and amplitude. In addition, based on the proposed method, the aperture size is small and the flat-topped beamwidth is flexible.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
  • All-Textile On-Body Antenna for Military Applications

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      Authors: Esra Çelenk;Nurhan Türker Tokan;
      Pages: 1065 - 1069
      Abstract: An all-textile cavity-backed substrate integrated waveguide (SIW) antenna is proposed for military applications. The antenna matches standard military badge size. The aircraft-shape badge antenna that operates in X-band is designed for air force. SIW cavity and meandered slots that form the body and wing of the figure provide resonance at 8 GHz with 26% bandwidth. Symmetrical boresight patterns with very low sidelobes are observed. The measured gain and efficiency of the structure are 5.2 dBi and 79.2% at 8 GHz, respectively. This efficiency value is the highest among other SIW cavity textile-antennas. The antenna is investigated on conformal surfaces, as well. Bending of the antenna to follow body movements does not deteriorate performance of the textile antenna sensor. The peak specific absorption rate value over 10 g of tissue was 0.53 and 0.69 W/kg for 30 dBm input power for female and male breasts, which makes it suitable as an on-body antenna. The badge antenna is fabricated with standard textile fabrication techniques and its simulation performance is confirmed successfully by measurements. Usage of standard off-the-shelf parts for the assembly and fabrication with standard textile fabrication techniques enables simple and cost-effective mass production of the proposed badge antenna.
      PubDate: May 2022
      Issue No: Vol. 21, No. 5 (2022)
       
 
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