A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z  

  Subjects -> ELECTRONICS (Total: 207 journals)
The end of the list has been reached or no journals were found for your choice.
Similar Journals
Journal Cover
IEEE Antennas and Wireless Propagation Letters
Journal Prestige (SJR): 1.047
Citation Impact (citeScore): 4
Number of Followers: 90  
 
  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 Publication Information

    • 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: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Editorial Status of AWPL

    • Free pre-print version: Loading...

      Authors: Christophe Fumeaux;
      Pages: 1 - 3
      Abstract: Presents the editorial for this issue of the publication.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Design and Rectangular Waveguide Validation of 2-Bit Wideband
           Reconfigurable Reflective Metasurface Element in X-Band

    • Free pre-print version: Loading...

      Authors: Xiangjin Ma;Jiaqi Han;Tong Wang;Silong Chen;Yajie Mu;Haixia Liu;Long Li;
      Pages: 4 - 8
      Abstract: This letter presents a new design and rectangular waveguide validation of a wideband 2-bit reconfigurable reflective metasurface (RRM) element in the X-band. The element consists of a U-slot microstrip patch, a ground plane, and a 2-bit reflection-type phase shifter (RTPS) controlled by four p-i-n diodes. The direct circuit (DC) biases are elaborated for the 2-bit RTPS so that only two DC bias lines are required to regulate the four p-i-n diodes. The proposed RRM element has a wideband 2-bit phase resolution from 9.1 to 10.85 GHz and can be recognized with great angle stability. The rectangular waveguide experiment was conducted to prove the effectiveness of the proposed element further. The experimental results show that the 17.5% relative bandwidth is achieved under a total phase difference of 270° ± 20° with reflection losses less than 3 dB.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Compact Hybrid Choke Rings for Dual-Band Circularly Polarized GPS Antenna

    • Free pre-print version: Loading...

      Authors: Mengmeng Sun;Jingyi Qian;Xudong Bai;Liguo Zhou;Yanting Lv;Fanwei Kong;Weiren Zhu;Ronghong Jin;
      Pages: 9 - 13
      Abstract: This letter presents the compact hybrid choke rings for the dual-band circularly polarized global positioning system (GPS) antenna, in order to suppress the surface wave propagation and reduce the back lobe levels. The designed dual-band circularly polarized antenna is center-fed and composed of two radiation patches. The novel compact hybrid choke rings are introduced to reduce the radiation back lobes and improve the front to back ratio effectively. The measured results show that the return loss of the antenna is greater than 10 dB and the bandwidth covers GPS L2 from 1.168 to 1.238 GHz and GPS L1 from 1.543 to 1.599 GHz. In the working bands, the front to back ratio of the proposed antenna is greater than 30 dB.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • A Polarization-Insensitive Dual-Band FSS With High Selectivity and
           Independently Switchable Characteristics

    • Free pre-print version: Loading...

      Authors: Bixiao Jiang;Haoquan Hu;Jing Tian;Shiwen Lei;Menglong Chen;Bo Chen;
      Pages: 14 - 18
      Abstract: The investigation of dual-band frequency selective surface (FSS) has attracted a great deal of attention over the past few decades. However, the existing reconfigurable dual-band FSSs exhibit first-order responses with poor frequency selectivity. In this letter, a polarization-insensitive dual-band FSS with a rotationally symmetrical receiver–transmitter unit-cell configuration that exhibits a second-order response is presented. p-i-n diodes are loaded on separate layers to achieve the independent switching of two passbands. The full-wave simulation results are presented, and an equivalent circuits model is also presented to analyze the operation principle of the proposed FSS. The measurement results of our fabricated prototype indicate that the device exhibits two independently switchable polarization-insensitive transmission bands centered at 3.06 and 4.33 GHz. The shape factors representing the selectivity of the transmission band are 2.44 and 2.46, respectively, which are approximately 1/4–1/2 times that of the existing reconfigurable dual-band FSSs. The proposed FSS exhibits angular stability up to 40$^{circ }$ below 5 GHz. This work paves the way toward high selectivity reconfigurable dual-band FSS.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Diversity Order and Measure of MIMO Antennas in Single-User, Multiuser,
           and Massive MIMO Wireless Communications

    • Free pre-print version: Loading...

      Authors: Rakhesh Singh Kshetrimayum;Mohit Mishra;Sonia Aïssa;Shiban K. Koul;Mohammad S. Sharawi;
      Pages: 19 - 23
      Abstract: In this letter, the diversity order (DO) and the diversity measure (DM) of multiple-input multiple-output (MIMO) antennas in generic single-user, multiuser, and massive MIMO wireless communications are calculated for several practical case studies. These performance metrics are calculated from the antenna correlation coefficient (ACC) matrix. The DO is calculated from the rank of the ACC matrix, and the DM is obtained from the trace and Frobenius norm of the ACC matrix. Numerical results are provided. In particular, it is shown that though the DM is always less than the DO, it incorporates the effect of antenna correlation on the diversity gain in a better way.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Array Decomposition Method for Arbitrary-Element Regular Arrays Using
           Higher Order Basis Functions

    • Free pre-print version: Loading...

      Authors: Magnus Brandt-Møller;Michael Mattes;Olav Breinbjerg;Min Zhou;Oscar Borries;
      Pages: 24 - 28
      Abstract: The full-wave array decomposition method for regular antenna arrays with arbitrary elements using higher order hierarchical basis functions is investigated. We show that the use of higher order basis functions results in significantly reduced memory consumption and computation time for a $mathbf {10!times!10}$ element conical horn array with an aperture size of $22!times!22lambda$, without the need for analytical nor numerical approximations. In addition, we demonstrate that by employing higher order basis functions, the far-field error is considerably lower than by using common first-order basis functions for the same total number of unknowns.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Circularly Polarized V-Band Orthomode Transducer

    • Free pre-print version: Loading...

      Authors: Shoukry Shams;Abdullah Muhammad Mahfouz;Mahmoud Elsaadany;Mohamed A. Moharram Hassan;Ghyslain Gagnon;Ahmed A Kishk;
      Pages: 29 - 33
      Abstract: A compact septum-based orthomode transducer (OMT) is designed to provide dual circularly polarized states for horn antennas. The OMT is backfed by two rectangular ports separated by a stepped tapered septum from thick to thin walls toward the common port. The OMT covers 16.7% fractional bandwidth in the V-band (55–65 GHz), which coincides with the fifth generation and beyond (5 GB) communications standards and intersatellite communications. The OMT performance is evaluated by measuring the back-to-back scattering parameters. Measured insertion loss is below 1.3 dB, whereas the isolation between the rectangular ports remains beyond 17 dB in the operating band.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Low-Frequency Dual-Driven Magnetoelectric Antennas With Enhanced
           Transmission Efficiency and Broad Bandwidth

    • Free pre-print version: Loading...

      Authors: Ning Xiao;Yao Wang;Lei Chen;Guoqiang Wang;Yumei Wen;Ping Li;
      Pages: 34 - 38
      Abstract: Low frequency (LF) dual-driven magnetoelectric (i.e., DDME) antennas are proposed, which include a pair of self-biased magnetoelectric (ME) heterostructures (i.e., Ni/Metglas/ [Pb(Zr,Ti)O3]5/Metglas/Ni) wrapped with small coils. For the DDME transmitter, the [Pb(Zr,Ti)O3]5 layers are designed as a piezoelectric transformer. This enhances the transmitted magnetic field significantly due to the dual-driven mode: the generated magnetic field of transmitting coils driven by the transformer at the magneto-mechanical resonance (MMR) and magnetization oscillation of magnetostrictive layer driven by the mechanical stress of inverse piezoelectric effect. Meanwhile, the DDME receiver consists of a self-biased ME heterostructure wrapped with search coils, whose signal-to-noise ratio (SNR) is improved due to the synergistically induced voltage of Faraday law's induction and ME effects. The nonmonotonic inductance of search coils near MMR broadens the bandwidth (1904 kHz) due to the LC resonances at multiple frequencies. The letter indicates that the DDME antenna achieves a communication distance of 11 m with power consumption of 212.7 mW, whose operation distance and channel capacity (12.54 kbit/s) are 1.69 times and 10.62 times larger than that of ME antenna (i.e., Ni/Metglas/[Pb(Zr,Ti)O3]5 /Metglas/Ni). The communication distance can be further increased to 170 m with a larger DDME antenna. Furthermore, the DDME antenna can realize more robust ASK modulation compared to ME antenna.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • A Broadband Circularly Polarized Planar Antenna Array Using
           

    • Free pre-print version: Loading...

      Authors: Qingquan Tan;Kuikui Fan;Weiliang Yu;Yufeng Yu;Guo Qing Luo;
      Pages: 39 - 43
      Abstract: This letter proposes a Ka-band broadband circularly polarized (CP) planar array based on the magneto-electric (ME) dipole structure. The antenna element consists of linearly polarized (LP) ME-dipole and two rotationally symmetrical bent strips. The two strips are connected to the opposite side of the LP ME-dipole to obtain a rotating electric field required by CP radiation. A feed structure of microstrip is implemented to excite the antenna element through an H-shaped coupling slot. The tightly coupled array technique is adopted to enhance the axial ratios (ARs) of the element. The proposed CP element realizes an AR bandwidth of 28%. Then, an 8 × 8 array with a 1-to-64 full-corporate feeding network is designed for experimental validation. The test results indicate that the 8 × 8 array prototype exhibits an impedance bandwidth of 50% covering 24 to 40 GHz, a 3 dB AR bandwidth of 28% covering 26.7–35.3 GHz, a gain between 20.6 and 22.1 dBic over the whole overlapped bandwidth, and a radiation efficiency higher than 75%. Attributed to the excellent CP performance and ease of integration with front-end circuits, the designed array is a good select for Ka-band wireless and satellite communications.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Synthesis of Thinned Planar Arrays Based on Precoded Subarray Structures

    • Free pre-print version: Loading...

      Authors: Jiehuan Zhang;Xiaolian Mao;Miao Zhang;Jiro Hirokawa;Qing Huo Liu;
      Pages: 44 - 48
      Abstract: A thinning method based on precoded subarray structures is proposed for planar arrays. It introduces the matrix descriptions, including the subarray structure matrix S and the coefficient vector K, and transforms the thinning of a planar array into the arrangement of predetermined subarrays with specified thinning rates. This process effectively leads to order reduction and achieves fast optimization. We apply the evolutionary algorithm to accomplish the ideal radiation performance iteratively. The dependence of the array performance on S and K is also investigated. For demonstration, the 10×20- and 23×23-element arrays are optimized. By comparing with the traditional thinning methods, it is verified that the proposed method not only provides us with lower sidelobes and narrower beamwidth but also avoids the random element arrangement. In addition, the introduction of precoded subarrays may further reduce production and maintenance costs, especially from engineering implementation and mass production perspectives.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • A Low-Profile Flexible Dual-Band Antenna With Quasi-Isotropic Radiation
           Patterns for MIMO System on UAVs

    • Free pre-print version: Loading...

      Authors: Hong Tang;Cory J. Bulger;Tom Rovere;Bowen Zheng;Sensong An;Hang Li;Yunxi Dong;Mohammad Haerinia;Clayton Fowler;Stephen Gonya;Wei Guo;Hualiang Zhang;
      Pages: 49 - 53
      Abstract: In this letter, a low-profile flexible dual-band quasi-isotropic antenna based on half-wavelength crossed dipoles is developed for unmanned aerial vehicle (UAV) applications. Specifically, to decrease the antenna profile, a coaxial structure is used to feed the antenna and no external balun is applied. Theoretical and numerical analyses of the designed antenna were conducted. To validate the design concept, an antenna prototype was fabricated and characterized. Good agreements have been observed between simulations and measurements. The measured radiation patterns show that the gain deviations across the whole spherical radiation surface are less than 7.5 dBi at 2.4 GHz and less than 8.7 dBi at 4.6 GHz. For the purpose of system demonstration, a 2 × 2 multiple-input–multiple-output (MIMO) system employing the proposed antenna was assembled. The resulting dual-band MIMO system was deployed on a UAV for ground test, validating its potential for performance improvement of UAV communications.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Born Iterative Method Based on Convolutional Dictionary Learning for
           Inverse Scattering Problems

    • Free pre-print version: Loading...

      Authors: Longhao Xie;Yao Huang;Jianjian Huo;Qing Zhao;
      Pages: 54 - 58
      Abstract: In this letter, a Born iterative method based on convolutional dictionary learning is proposed to solve inverse scattering problems. The method is inspired by compressed sensing, which indicates that the contrast can be represented by nonzero expansion coefficients with respect to expansion bases. The inverse scattering problem is changed from solving the contrast to solving the nonzero expansion coefficients under the expansion bases. In our method, the bases are obtained by convolutional dictionary learning from a set of training data, which learn and characterize the intrinsic laws of the local contrast. The performance of the proposed method is verified using simulated data. We compare it with the Born iterative method and the contrast source inversion method, and the results show that the proposed method can get better results.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Dual-Polarized Dual-Band-Notched Frequency-Selective Absorber With High
           Design Freedom

    • Free pre-print version: Loading...

      Authors: Xin Jie Hao;Xian Qi Lin;Xin Mi Yang;Yi Hong Su;Yao Yao;Yu Lei Yang;
      Pages: 59 - 63
      Abstract: A dual-polarized frequency selective absorber (FSA) with dual notch bands is proposed in this letter, in which the lower notch-band and upper notch-band can be adjusted independently and mechanically. The proposed design is a dual-layer structure consisting of two dielectric substrates with etched metal patterns, separated by an air layer in the middle. A bowtie-shaped metal array on the top layer provides broadband absorption. The dual-band-notched with high design freedom property is achieved by dual square loops with parasitic L-shaped elements on the bottom layer and the U-slot etched on the bow-tie-shaped metal pattern. A prototype of FSA exhibits good absorption from 4.58 to 6.8 GHz, 8.52 to 12.5 GHz, and 13.73 to 15.15 GHz, whereas two typical reflective bands are obtained from 7.11 to 7.66 GHz and 12.95 to 13.59 GHz. The center notch-frequency tunable range is from 6.88 to 7.78 GHz and 12.05 to 13.36 GHz, for the lower and upper notch, respectively. Furthermore, an equivalent circuit model is presented. Good agreement is obtained among simulation results, circuit analysis, and final measured response.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Frequency-Reconfigurable Antenna With Wide- and Narrowband Modes for Sub-6
           GHz Cognitive Radio

    • Free pre-print version: Loading...

      Authors: Truong Khang Nguyen;Cong Danh Bui;Adam Narbudowicz;Nghia Nguyen-Trong;
      Pages: 64 - 68
      Abstract: This letter presents a frequency-reconfigurable antenna for cognitive radio application in sub-6 GHz 5G band. The proposed antenna consists of a wideband (WB) monopole integrated with a narrowband microstrip patch in a single-layer substrate. Two PIN diodes are employed to switch between the WB sensing mode and narrowband (NB) communication mode. Three varactor diodes are implemented on the patch to continuously tune the operating frequencies in the NB mode. The proposed antenna produces a wide bandwidth of 54.2% (3.19–5.56 GHz) for the sensing mode and a continuously tunable bandwidth of 44% (3.4–5.32 GHz) for the communication mode. Both modes present good radiation characteristics with peak measured realized gains of 6.02 and 5.37 dB, respectively.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Design of Switchable Frequency-Selective Rasorber With A-R-A-T or A-T-A-R
           Operating Modes

    • Free pre-print version: Loading...

      Authors: Xiangkun Kong;Xin Jin;Xuemeng Wang;Weihao Lin;He Wang;Zuwei Cao;Steven Gao;
      Pages: 69 - 73
      Abstract: This letter presents a switchable frequency-selective rasorber (SFSR) with two operating modes. Switching from transmission to reflection can be achieved by appropriately adding feeders and PIN diodes based on cascaded two-dimensional lossy and lossless frequency-selective surface screens. The proposed SFSR can realize out-of-band absorption. Analysis of the equivalent circuit model can be useful for achieving a switchable rasorber. As the state of the PIN diodes changes, the working state of the SFSR can be switched from low-frequency reflection and high-frequency transmission to low-frequency transmission and high-frequency reflection, respectively. In the final-revision simulation of the working band of the SFSR, in the on state, reflection and transmission peaks of −0.55 dB at 4.06 GHz and −0.52 dB at 5.97 GHz, respectively, are achieved; in the off state, the transmission and reflection peaks of −0.31 dB at 4.04 GHz and −0.26 dB at 6.01 GHz, respectively, are obtained. A prototype sample is developed and validated. The results are in good agreement with those of the final-revision simulations. The proposed design can be used in intelligent antijamming communication.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Miniaturized Triple-Band Circular- Polarized Implantable Patch Antenna for
           Bio-Telemetry Applications

    • Free pre-print version: Loading...

      Authors: Yara Ashraf Kamel;Hesham A. Mohamed;Hala ELsadek;Hadia Mohamed ELhennawy;
      Pages: 74 - 78
      Abstract: This letter presents a triple-band antenna with circular polarization (CP) behavior embedded in a lossy tissue for bio-telemetry applications. The triple bands are the Industrial, Scientific, and Medical (868–868.6 MHz and 2.4–2.4835 GHz) bands and the midfield band (1.824–1.98 GHz). These bands are used for physiological information telemetry, power-saving, and wireless power transfer in medical devices. CP behavior at three bands is the key feature of the designed implantable antenna, compared with literature dual-band CP antennas. Moreover, the size of the designed antenna is compact of 50.8 mm$^{3}$. Finally, the specific absorption rate and link margin are calculated for the consideration of health safety and reliable communication aspects.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Low-Profile Laptop Antenna Design for Wi-Fi 6E Band

    • Free pre-print version: Loading...

      Authors: Chow-Yen-Desmond Sim;Jayshri Kulkarni;Shr-Hua Wang;Shi-Ying Zheng;Zhi-Hao Lin;Shu-Chuan Chen;
      Pages: 79 - 83
      Abstract: In this letter, a low-profile (3.5 mm) dual-band operation laptop antenna designed for wireless fidelity 6E (2.4/5/6 GHz) bands is proposed. The proposed antenna is a double-slit loaded modified inverted-L antenna (ILA) structure that can excite multifrequency mode, allowing it to fully cover the desired 5 and 6 GHz bands (5150–7125 MHz). To further cover the 2.4 GHz band (2400–2485 MHz), a C-shaped coupling strip is further printed behind the modified ILA. Besides exhibiting a small planar size of only 22.3 mm × 3.5 mm that allows it to be applied in a narrow screen bezel laptop, the proposed antenna can still yield desirable measured 10 dB bandwidths of 2.4–2.485 and 4.74–7.26 GHz, with good antenna efficiency of more than 40% and 61%, respectively.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • A Low-Cost 3-D Printed THz Open Resonator Antenna

    • Free pre-print version: Loading...

      Authors: Yuan-Long Li;Kwai-Man Luk;
      Pages: 84 - 88
      Abstract: We propose a design of an open resonator antenna to fulfill the requirements of high gain and low cost at 0.1 THz. A planar cavity with a loaded phase-shifting periodic structure is used to imitate a spherical cavity, which helps to support higher order modes and, hence, widen the bandwidth. The design procedure is introduced in detail. With the help of high-precision three-dimensional printing technology, the periodic structure can be manufactured with a relatively lower cost and complexity. Measurements were carried out to prove that the proposed antenna can achieve a 3 dB gain bandwidth of 13% and a peak gain over 16.8 dBi.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Reflect–Transmit-Array Antenna With Independent Dual Circularly
           Polarized Beam Control

    • Free pre-print version: Loading...

      Authors: Jichao Feng;Zehong Yan;Shuyang Yang;Fangfang Fan;Tianling Zhang;Xiaosong Liu;Xiaofei Zhao;Qinglin Chen;
      Pages: 89 - 93
      Abstract: In this letter, we propose a dual circularly polarized reflect–transmit-array (RTA) antenna with independent beam control. It can transmit left-hand circularly polarized (LHCP) wave as transmitarray antenna and reflect right-hand circularly polarized (RHCP) wave as reflectarray antenna at 8.7–10.2 GHz. In addition, 360° phase shift for each circularly polarized wave can be achieved by rotating the top and bottom patches. A 20 × 20-unit cell RTA is designed, fabricated, and measured. For the LHCP radiation, the measured results show that the 3 dB gain bandwidth and axial ratio (AR) bandwidth are 13.7% (8.8–10.1 GHz) and 15.9% (8.7–10.2 GHz), respectively. For the RHCP radiation, the measured 3 dB gain bandwidth and AR bandwidth are 11.4% (9.1–10.2 GHz) and 12.6% (8.9–10.1 GHz). The peak aperture efficiencies for LHCP and RHCP radiations are 45.5% at 9.2 GHz and 41.8% at 9.6 GHz, respectively.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Study on Propagation Properties of Orbital Angular Momentum Modes in
           Plasma Sheath Turbulence for Power-Exponent-Phase Airy Beams

    • Free pre-print version: Loading...

      Authors: Chaoxu Chen;Wei Chen;Qingqing Deng;Lixia Yang;Wenzhe Deng;Mengru Zeng;Qiqi Ma;Zhixiang Huang;
      Pages: 94 - 98
      Abstract: The theory of random phase screen is adopted to establish the propagation model of power-exponent-phase airy (PEPA) beams in plasma sheath turbulence (PST) conditions. The propagation model can determine the changes in intensity, phase, and orbital angular momentum (OAM) mode distribution of PEPA beams under PST. Simulation results reveal that PEPA beams in multiple OAM modes at the source field can better suppress PST than the conventional vortex beams because the influence of turbulence is dispersed in different OAM modes. Moreover, compared with power-exponent-phase Laguerre–Gaussian (PEPL) beams, PEPA beams are better suited for transmission under plasma turbulence because of their self-focusing and self-healing properties. The results provide a theoretical basis for studying communication problems during PST.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • An Ultralow-Loss and Lightweight Cellulose-Coated Silica Foam for Planar
           Fresnel Zone Plate Lens Applications in Future 6G Devices

    • Free pre-print version: Loading...

      Authors: Mikko Kokkonen;Petra S. Pálvölgyi;Rafal Sliz;Heli Jantunen;Krisztian Kordas;Sami Myllymäki;
      Pages: 99 - 103
      Abstract: Several passive components of fifth-generation (5G) and future sixth-generation (6G) telecommunication devices require substrate materials of very low dielectric permittivity and losses to avoid wave absorption, reflection, and interference. Apart from their dielectric properties, these materials shall be also affordable and sufficiently robust to enable postprocessing and integration of functional electrical components. Herein, we demonstrate a Fresnel zone plate lens for operation at 300 GHz, whose structure is supported on substrate made of an ultraporous silica foam with a nanocellulose thin film coating. The effective dielectric permittivity and loss of the substrate (ϵr = 1.018 ± 0.003 and tan δ < 3 × 10−4 at 300 GHz) is close to that of air. Experiments show that the fabricated Fresnel zone plate lens connected to a waveguide with total gain of 20 dB and angular beamwidth of 2.9° in good agreement with microwave simulations. The proposed lens structure has additional advantages such as small volume, ultralight weight, and simulations indicate 60 GHz bandwidth making it particularly appealing for radio front-ends of future 6G devices.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Dual-Polarized SIW Leaky-Wave Antenna Based on Mode-Multiplexed Feeding
           Structure

    • Free pre-print version: Loading...

      Authors: Zhenzhong Chen;Dongfang Guan;Zuping Qian;Wen Wu;
      Pages: 104 - 108
      Abstract: This letter presents a novel dual-polarized leaky-wave antenna (LWA) based on mode-multiplexed feeding structure (FS). Substrate integrated waveguide with groove arrays is exploited to achieve mode-multiplexed FS and two working modes are excited at the same frequency range utilizing different feeding methods. Thirteen dumbbell-shaped patches are placed above the proposed FS and fed through coupling, achieving leaky-wave radiation. When the FS is excited by the microstrip line port, even-mode is obtained and the LWA works in horizontal polarization. With the slotline port excitation, odd-mode is excited and the LWA works in vertical polarization. Therefore, a dual-polarized LWA is realized by using one single transmission line with one type of radiating elements, leading to mode multiplexing in feeding structure and polarization multiplexing in radiating part. A prototype was fabricated and tested for verification. Measured results reveal that the beams can scan from backward to forward under two polarizations. Within the working bandwidth, the cross polarization below −20 dB is realized in the beam-scanning plane.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Modified Slotted Patch Antenna With Metasurface as Superstrate for
           Dual-Band Applications

    • Free pre-print version: Loading...

      Authors: Diptiranjan Samantaray;Sambit Kumar Ghosh;Somak Bhattacharyya;
      Pages: 109 - 113
      Abstract: This letter presents the design, circuit model analysis, and realization of a novel metasurface-based low-profile slotted patch antenna for dual-band applications in the C and X-bands. The antenna prototype comprises a modified slotted patch and a 7×7 array of periodic metasurface (MS) as superstrate configuration. Both the radiating patch and the MS layer have been designed over FR4 dielectric substrate while the overall dimension of the proposed antenna being 1.03λ0×1.03λ0×0.15λ0 only, where λ0 is the free-space wavelength at 8.62 GHz. The −10 dB impedance bandwidth of the proposed antenna has been realized at two distinct frequency bands ranging from 4.18 to 4.44 GHz and 8.11 to 11.14 GHz. The fractional bandwidths of 6.1% and 35.15% have been achieved at 4.26 and 8.62 GHz, respectively. The equivalent circuit model of the proposed prototype has been sequentially developed to validate the electromagnetic simulated results. The antenna radiates in the boresight direction, with a maximum realized gain of 8.72 dBi at 10.99 GHz and radiation efficiency of 91%. The proposed prototype has also been fabricated and the experimentally measured results are in good resemblance with the simulated one.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • A Wideband Low-Profile Dual-Polarized Hybrid Antenna Using Two Different
           Modes

    • Free pre-print version: Loading...

      Authors: Changfei Zhou;Jiaxing Sun;Wen-Wen Yang;Min Li;Hang Wong;
      Pages: 114 - 118
      Abstract: The fusion of dipole and patch antennas is proposed to achieve a wide band and a low profile. By loading parasitic elements, the hybrid modes of dipole and patch are excited simultaneously with the same feeding and shared aperture. Employing a double-layer-metal artificial magnetic conductor (AMC) to replace PEC as the reflector, the height is reduced from 22.5 mm (0.165 λ at 2.2 GHz) to 17.5 mm (0.128 λ). Two shorting pins are loaded between the radiator and the reflector ground to improve the isolation within the whole band. A prototype of the proposed antenna with double-layer AMC is fabricated and measured. The measured results show that the proposed antenna has a wide impedance bandwidth of 1.68–2.84 GHz (1.16 GHz, 51.3%) and high isolation of more than 25.5 dB. In addition, a stable gain of 8.8 ± 0.2 dBi and a stable radiation pattern with a half-power beamwidth of 59.6o ± 3.45o are achieved without any ground walls.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Fast Analysis of Metasurfaces Composed of Asymmetric Scatterers Using FDTD
           With Anisotropic Surface Susceptibility Model

    • Free pre-print version: Loading...

      Authors: Xiao Jia;Fan Yang;Maokun Li;Shenheng Xu;
      Pages: 119 - 123
      Abstract: The finite-difference time-domain (FDTD) method with surface susceptibility model (SSM) had been developed to accelerate metasurfaces analysis before. However, the previous work is confined to symmetric scattering elements. This letter thus generalizes the FDTD-SSM algorithm to analyze metasurfaces composed of asymmetric scattering elements. We first classify the problem and then derive and present the corresponding FDTD-SSM equations. The validity and efficiency of the proposed FDTD-SSM algorithms are demonstrated through numerical experiments.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Wideband Wide-Beam Hybrid Dielectric Resonator Antenna Using Uniaxial
           Material

    • Free pre-print version: Loading...

      Authors: Zi-Kang Chen;Li Zhang;Zibin Weng;Rui-Yang Li;
      Pages: 124 - 128
      Abstract: In this letter, a wideband wide-beam rectangular dielectric resonator antenna (DRA) employing uniaxial anisotropic material is presented. To the best knowledge of the authors, the uniaxial anisotropic dielectric is used in wide-beam DRAs for the first time. By tuning the uniaxial permittivity tensor of the rectangular dielectric, the radiation from the top wall of the DRA is enhanced which improves the gain at low elevation angle in the E-plane. Both the feed slot mode and the fundamental $text{TE}_{{111}}^{mathrm{y}}$ mode are merged to broaden the bandwidth. When a grounded substrate is added and four trapezoidal notches are etched on the ground, the half-power beamwidth (HPBW) in the H-plane is broadened. The measured results achieve an impedance bandwidth of 35.7% over a band of 2.65–3.8 GHz with HPBWs of at least 250° and 162° in the E- and H-planes, respectively.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • An All-Metal, Simple-Structured Reflectarray Antenna With 2-D
           Beam-Steerable Capability

    • Free pre-print version: Loading...

      Authors: Shaofeng Bi;Liang Xu;Xiaoyu Cheng;Yunfei Sun;Qiang Zhang;Chengwei Yuan;
      Pages: 129 - 133
      Abstract: An all-metal reflectarray (RA) element based on the variable-rotation technique is presented in this letter. The RA element, based on an elliptical inner conductor and a circular outer conductor, exhibits continuous 360° phase coverage with negligible element loss over a wide range of incident angles and frequencies. A 10 GHz prototype with 121 manually rotated elements was simulated, fabricated, and tested. The proposed RA antenna has two-dimensional beam-steerable capability up to 45° elevation angle. The measured results agree well with the simulated counterparts. For demonstration, four different steering cases are presented as examples by manually adjusting the rotation angle of the RA elements. The maximum measured antenna gain is 26.2 dBi, corresponding to an aperture efficiency of 66%. A 1.3 dB gain drop was measured during beam scanning from 0° to 40°.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Singular Phase Characteristics of Electromagnetic Absorbers and a
           Framework for Low-RCS Target Detection

    • Free pre-print version: Loading...

      Authors: Nitish Kumar Gupta;Gaganpreet Singh;Sapireddy Srinivasu;Harshawardhan Wanare;Kumar Vaibhav Srivastava;J. Ramkumar;S. Anantha Ramakrishna;
      Pages: 134 - 138
      Abstract: We conceptualize, numerically validate, and experimentally demonstrate a scheme for distant line-of-sight detection of low-observable targets, such as those covered by metamaterial absorbers, by solely relying on their nontrivial phase characteristics. Relying upon the temporal coupled-mode theory (TCMT), first, we put forward a generalized description of open resonators where we identify the presence of a spectral inflection point in the phase response function as the signature of interest. Thereafter, a realistic phase response function has been modeled and analyzed by incorporating the propagation aspects as well as band-limited Gaussian noise. Change of curvature information owing to the resonant absorption is then ascertained from this involute phase response by developing an algorithm. For pragmatic scrutiny of our proposition, we design a singly resonant (at 12 GHz) wideband resistive sheet-based metamaterial absorber providing $-$10 dB absorption across the X- and Ku-bands and employ its de-embedded scattering parameters to confirm the existence of inflection point around 12 GHz. As a final validation, the metamaterial absorber has been fabricated using ITO/PET sheets, and its phase characteristics have been measured in a pseudomonostatic configuration. The information regarding the presence of resonant absorption has been then ascertained by the algorithm extracted phase, thereby validating our proposition.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Wideband Calibration Network for Multichannel Antenna Array Feeding
           Network

    • Free pre-print version: Loading...

      Authors: Wenjie Feng;Chengzhi Wang;Wenquan Che;Quan Xue;
      Pages: 139 - 143
      Abstract: In this letter, a wideband calibration network using multilayer coupler is proposed for X-band antenna array feeding network. A high performance coupler is designed to ensure consistency for the coupling of the series-fed structure. By using a serpentine feedline and making all channels the same length, phase imbalance is decreased. To reduce lateral leakage, cross-talk and mutual coupling, the vias-shielded structure and metal spacer are used. To validate the proposed calibration network design, a wideband calibration network is fabricated and measured. Measured results show that the coupling amplitude fluctuates mainly in the range of 29–37 dB with phase imbalance less than 5°, the isolation of all ports is better than 38 dB and voltage standing wave ratio is less than 1.7.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Transmission-Band-Switchable Absorptive/ Transmissive Frequency Selective
           Surface Using Liquid Metal

    • Free pre-print version: Loading...

      Authors: Weigang Liu;Peng Li;Zhihua Zhang;Qunbiao Wang;Wanye Xu;
      Pages: 144 - 148
      Abstract: A transmission-band-switchable absorptive/transmissive frequency selective surface (ATFSS) based on liquid metal is proposed herein. The ATFSS realizes C-band absorption, and the transmissive Ku-band can be turned on or off using loaded or unloaded liquid metal and by changing the spacing between the lossy layer and the transmission layer. The simulation shows that the ATFSS maintains an absorption rate of>80% at 3.1–8.9 GHz; when the transmission band is opened, the |S21| < 3 dB band is 10.7–17.22 GHz. When the transmission band is closed, all the electromagnetic waves at the Ku-band are reflected. An ATFSS prototype was fabricated, and the measurement results effectively validated the above design. Moreover, the ATFSS could be used in high-temperature environments owing to the good thermal conductivity of liquid metal.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Short Asymmetrical Inductive Dipole Antenna for Direct Matching to High-Q
           Chips

    • Free pre-print version: Loading...

      Authors: C. Ballesteros;S. Vega;M. C. Santos;L. Jofre-Roca;
      Pages: 149 - 153
      Abstract: A planar antenna structure based on a folded asymmetrical dipole is presented, whose geometrical parameters are seen to independently determine either the real or the imaginary parts of the complex radiation impedance. This unique feature allows very efficient and wideband conjugate matching coupling to nonconventional RF sources of arbitrary internal impedance, i.e., small resistance with large and negative reactance. The antenna theoretical framework is developed and an optimized design to match a photodiode is manufactured and measured. The results show a fractional bandwidth of about 20% in the 28 GHz band.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Dual-Band Dual-Sense High-Gain Circularly Polarized Metasurface Antenna
           Using Characteristic Mode Analysis

    • Free pre-print version: Loading...

      Authors: Chao Huang;Chen-Jiang Guo;Yi Yuan;Jun Ding;
      Pages: 154 - 158
      Abstract: A novel dual-band dual-sense circularly polarized (CP) metasurface (MTS) antenna with high-gain performance is designed. A 2 × 3 square patch array, as the basic MTS, is investigated at first. We observe that besides the two fundamental modes with desired broadside patterns, the basic MTS also possesses two higher order modes with high-level sidelobes. The sidelobes are yielded by the reverse currents on the middle patches of the MTS, which can be canceled by modifying the middle patches into poor radiators. Then, two coupled-fed slots are employed to excite two fundamental modes and two higher order modes of the modified MTS. Moreover, the fields of the four orthogonal broadside modes are adjusted to meet the magnitude and phase requirements of the CP wave. All the mentioned processes are under the guidance of the characteristic mode analysis. Finally, the proposed MTS antenna is fabricated and measured. The measured results agree well with the simulations, showing 3 dB axial ratio bandwidths of 4.37–4.45 and 6.03–6.24 GHz with CP waves in different handedness. The measured peak gains in the lower and higher bands are 10.22 and 10.72 dBic, respectively.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Low-Scattering Dipole Antenna Using Mushroom-Shaped Structure for
           Applications in Dual-Band Shared-Aperture Array

    • Free pre-print version: Loading...

      Authors: Guosheng Su;Wenquan Che;Wanchen Yang;Quan Xue;Bin-Long Bu;Peitao Liu;Litao Chen;
      Pages: 159 - 163
      Abstract: A low-scattering dipole antenna by loading mushroom-shaped electromagnetic structures is proposed and employed to design an aperture-shared antenna array with low blockage effect. The arm of the proposed dipole element consists of a square ring and a short branch, and the mushroom structure is loaded on the arm to realize low scattering characteristics. The low scattering low band (LB) element is used for a dual-band shared-aperture array; the results indicate the pattern distortion of the high band (HB) array caused by the LB element can be greatly reduced accordingly. Compared with HB antenna alone, the simulated maximum gain decrease is 1.55 dB and the maximum beamwidth deviation is 27.4° after adding the reference LB dipole without loading the mushroom-shaped structure. Meanwhile the two values are reduced to 0.55 dB and 6.4°, respectively, after the mushroom-shaped structure is loaded. For demonstration, an aperture-shared antenna array operating in the LB of 0.698–0.96 GHz and the HB of 3.4–3.8 GHz is designed and fabricated. The measured results show that the S-parameters and the pattern of the HB subarray with the proposed LB dipole change slightly, indicating that the proposed LB dipole can effectively suppress the scattering on the HB antenna. The results indicate the proposed design is suitable for multiband aperture-shared antennas in modern communication systems.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Polarization-Insensitive Absorptive/Transmissive Reconfigurable Frequency
           Selective Surface With Embedded Biasing

    • Free pre-print version: Loading...

      Authors: Patinavalasa Megh Sainadh;Aditi Sharma;Saptarshi Ghosh;
      Pages: 164 - 168
      Abstract: In this letter, a polarization-insensitive absorptive/transmissive reconfigurable frequency selective surface (RFSS) using p-i-n diodes is presented. The RFSS structure incorporates two periodically arranged metallic patterns on both sides of an FR4 dielectric substrate, where the p-i-n diodes are aligned symmetrically on the bottom surface. Depending upon the diode biasing conditions, the geometry behaves as a radar absorber and a bandpass filter under different working states. The simulated response exhibits a near-unity absorption response (having absorptivity of 93.51%) at 6.93 GHz during on state of the diode, whereas the incident electromagnetic wave gets transmitted through the structure at 5.62 GHz during off state. An embedded biasing circuitry has also been developed comprising metallic vias and inductors, such that the geometry displays polarization-insensitive and angularly stable responses for both states. The structure has been analyzed with the help of circuit modeling and other parametric variations to explain the switching methodology. A prototype has been fabricated and measured using the parallel-plate waveguide technique, which results in a good agreement with the simulated responses. Such RFSSs can be marked as a potential element for various radome applications.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Design of Dual-Port Pattern-Reconfigurable MIMO Antenna With Four
           Operating States Using the TCM

    • Free pre-print version: Loading...

      Authors: Guangshang Cheng;Minmin Tian;Long Zhang;Zhixiang Huang;
      Pages: 169 - 173
      Abstract: Based on the theory of characteristic modes (TCM), this letter presents a novel pattern-reconfigurable dual-port multiple-input–multiple-output (MIMO) antenna with four operating states at the 2.4 GHz ISM band. The proposed antenna consists of the rectangular platform (RP), excitation units, and reconfigurable feeding network. Four elaborated characteristic modes (CMs) of the RP can be stimulated effectively by six groups of balanced inductive exciters. By using a reconfigurable feeding network controlled by four switches, two orthogonal CMs associated with the two ports are switched, and four possible operating states for the reconfigurable MIMO antenna are generated. In order to demonstrate the proposed TCM-based conceptual design, a prototype is fabricated and the measured results agree well with the simulated ones. Furthermore, the port isolations of the proposed MIMO antenna are higher than 36 dB.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Design of Wideband Dual-Polarized ME Dipole Antenna With Parasitic
           Elements and Improved Feed Structure

    • Free pre-print version: Loading...

      Authors: Liangliang Zhao;Hailiang Zhu;Huiling Zhao;Ganyu Liu;Kai Wang;Jinchao Mou;Weiwei Zhang;Jianzhou Li;
      Pages: 174 - 178
      Abstract: A wideband dual-polarized antenna is proposed for base station applications. The proposed antenna is composed of two folded and hollowed out magnetoelectric dipoles placed crosswise, as well as a box-shaped reflector, the overall size is 0.97λ × 0.97λ × 0.27λ. Two Γ-shaped probes with a gradual change in size are used to excite the antenna. By adding parasitic elements to the feeding structure and box-shaped reflector, wide operating bandwidth from 1.59 to 3.65 GHz is realized, where the standing wave ratio is less than 2 and the fractional bandwidth is up to 78.6%. Meanwhile, stable radiation pattern, high front-to-back ratio, and steady boresight gain can also be seen over the whole band. Prototype is fabricated and the measured results verify that the proposed antenna could be a competitive candidate in base station applications.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • A Compact Wideband Low-Profile Metasurface Antenna Loaded With
           Patch-Via-Wall Structure

    • Free pre-print version: Loading...

      Authors: Dongxu Chen;Quan Xue;Wanchen Yang;Kuo-Sheng Chin;Huayan Jin;Wenquan Che;
      Pages: 179 - 183
      Abstract: This letter designs a miniaturized low-profile metasurface (MS) antenna with compact size, large bandwidth, and stable gain. First, a miniaturized MS structure using the via-wall capacitive loading is investigated. Different from the traditional square MS structure, this design loads via walls on both sides of the square patch to introduce large equivalent parallel-plate capacitance, which can reduce the size of the MS element by 50%. The stacked patches are then loaded horizontally along the side via walls to introduce additional edge capacitance for a further 10% size reduction. Finally, a miniaturized patch-via-wall MS element with small size of 0.061λ0×0.061λ0 can be obtained. For demonstration, the proposed miniaturized patch-via-wall MS structure is applied to realize a compact wideband antenna fed by a microstrip line through a coupling slot. Measured results show that the proposed patch-via-wall MS-based antenna can achieve a large impedance bandwidth of 43.1% (5.46–8.46 GHz), a small aperture size of 0.348λ0×0.348λ0 with a high gain of 6.18 dBi, and a thin thickness of 0.07λ0.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Dual-Band Antenna With Omni/Unidirectional Radiation Realized by
           Single Metal Plate

    • Free pre-print version: Loading...

      Authors: Li-Jie Xu;Zhenyu Nie;Xiaoyu Jin;Zhe Wu;Zhu Duan;
      Pages: 184 - 188
      Abstract: This letter proposes a novel dual-band antenna realized by single metal plate. The basic antenna structure is a λ/2 dipole with omnidirectional radiation pattern, operating at 1.4 GHz. To obtain a second working band with directional radiation, this dipole is folded, therefore forming an open-end slot in-between its two arms, serving as a magnetic dipole. Then, by properly exciting these two dipoles with 90° phase difference in time domain, the inherent 90° phase difference formed between the slot and the electric dipole is cancelled. As a result, cardioid radiation pattern is obtained at 3.7 GHz. The measured results show that an impedance bandwidth of 10.3% and 18.1% is achieved at these two bands, respectively, with omnidirectional radiation pattern at 1.4 GHz band, and unidirectional radiation with at 3.7 GHz with wide beamwidth.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Monolithically Integrated Coaxial Resonator-Based Filtennas Using SLA
           Three-Dimensional Printing

    • Free pre-print version: Loading...

      Authors: Kunchen Zhao;Dimitra Psychogiou;
      Pages: 189 - 193
      Abstract: This letter reports on a new class of highly-miniaturized coaxial-resonator-based filtennas alongside a monolithic integration concept using digital additive manufacturing. The filtenna approach is based on the co-design of a coaxial cavity resonator and an annular slot antenna that collectively perform as a radiating resonating node within a coupled-resonator-based bandpass filter. Beam direction can be controlled by altering the position of the radiating slot. A stereolithography apparatus (SLA) monolithic integration concept is proposed for size compactness and reduced weight. For proof-of-concept validation purposes, first-, second-, and third-order filtennas were analyzed through electromagnetic simulations. Experimental validation was performed through the manufacturing and testing of a second-order top-slot filtenna, a second-order and a third-order side-slot filtenna with the following characteristics: center frequency: 4.75 GHz, 4.8 GHz and 4.6 GHz, fractional bandwidth: 7.4%, 8.3%, and 7.6% and realized gain: 5.5 dBi, 2.6 dBi, and 2.6 dBi.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Polarization-Converting Metasurface Inspired Dual-Band Dual-Circularly
           Polarized Monopole Antennas for Off-Body Communications

    • Free pre-print version: Loading...

      Authors: Nibash Kumar Sahu;Sanjeev Kumar Mishra;
      Pages: 194 - 198
      Abstract: This letter investigates a novel technique to achieve circular polarizations (CPs) at 2.45 GHz ISM and 3.5 GHz WiMAX bands. The behavior is achieved by incidenting an $x$-polarized wave from a monopole antenna (MA) on a polarization-converting metasurface (PCMS). The PCMS operates in TM$_{10}$ and TM$_{20}$ modes that generate dual frequency bands and reflect a 90° phase-shifted y-polarized wave that, when combined with the 0° phase containing $x$-polarized wave, generates CP. To attain four separate combinations of phase-shift in terms of +90° and −90° in dual bands, four distinct 2×2 PCMSs are designed, which are designated as MS$_{1}$, MS$_{2}$, MS$_{3}$, and MS$_{4}$. The MS$_{1}$-based MA (A$_{1}$) produces left-hand CP (LHCP), whereas the MS$_{2}$-based MA (A$_{2}$) produces right-hand CP (RHCP) in both frequency bands. On the other hand, the MS$_{3}$-based MA (A$_{3}$) pr-duces RHCP in the lower band (LB) and LHCP in the higher band (HB), whereas the MS$_{4}$-based MA (A$_{4}$) produces LHCP in the LB and RHCP in the HB. A$_{3}$ is fabricated and measured, and the results are very close to the simulations. Each antenna has a wide impedance bandwidth, a high gain, and high efficiency with a low specific absorption rate (SAR) in the desired bands, which justifies their suitability for off-body communication.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Wideband Pattern-Reconfigurable Antenna With Switchable Monopole and
           Vivaldi Modes

    • Free pre-print version: Loading...

      Authors: Wentao Yuan;Jingjian Huang;Xiaofa Zhang;Kaibo Cui;Weiwei Wu;Naichang Yuan;
      Pages: 199 - 203
      Abstract: A novel design for radiation pattern-reconfigurable antenna is described in this letter. The design is based on a wideband Vivaldi antenna structure. Two different radiation patterns are achieved by switching the feeding paths to obtain two antennas operation modes, monopole mode and Vivaldi mode. The reconfigurable antenna can adjust the radiation patterns by controlling the bias voltage of pin diodes. Therefore, by combining the two radiation patterns, a broad coverage of reconfigurable pattern is generated. In addition, the pattern reconfigurable antenna can operate at a wide frequency band from 2.7 to 12 GHz. Details of the simulated and experimented results for the pattern-reconfigurable antenna are shown.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • A PO-Based Uniform Asymptotic Procedure for the Scattering From a
           Magnetically Conductive Half-Screen

    • Free pre-print version: Loading...

      Authors: Giovanni Riccio;Gianluca Gennarelli;Flaminio Ferrara;Claudio Gennarelli;Rocco Guerriero;
      Pages: 204 - 207
      Abstract: This article addresses reflection, transmission, and diffraction mechanisms due to a magnetically conductive half-screen lit by an incident plane wave. The proposed method is founded on the physical optics approximation of the equivalent surface currents under the validity of proper boundary conditions and works according to the uniform geometrical theory of diffraction. Resulting formulas are presented in simple form and are easy to manage. The validation tests employ data resulting from the radio frequency unit of a full-wave numerical tool.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Generation of Multiple Nondiffracting Beams Based on Transmission
           Metasurface in Microwave-Frequency Region

    • Free pre-print version: Loading...

      Authors: Hao Tang;Shuai Ding;Zhaojun Zhu;Xiong Wang;Zhengping Zhang;
      Pages: 208 - 212
      Abstract: In this letter, a method to generate multiple nondiffracting beams by a transmission metasurface is proposed. The unit cell consists of two layers of the same circular resonant patch and a medium layer in the middle. The unit cell is rotated by different angles to obtain a 360$^circ$ transmission phase shift. The method of generating multiple nondiffracting beams on the metasurface is realized by a multibeam shared-aperture method. Multiple subarrays are used to launch nondiffracting beams that propagate in different directions in a shared-aperture manner. Each subarray is independent and complementary to control the deflection of multiple nondiffracting beams more flexibly. In accordance with the method, three nondiffracting beams are generated by the same transmission metasurface. The metasurface is fabricated and measured and the results validate the proposed design method.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • A Wideband Circularly Polarized Dielectric Patch Antenna With a Modified
           Air Cavity for Wi-Fi 6 and Wi-Fi 6E Applications

    • Free pre-print version: Loading...

      Authors: Haoyue Jiang;Ningning Yan;Kaixue Ma;Yongqiang Wang;
      Pages: 213 - 217
      Abstract: In this letter, a novel wideband circularly polarized (CP) dielectric patch antenna (DPA) featuring low profile and relatively high gain property is investigated for Wi-Fi 6 and Wi-Fi 6E applications. Multiple modes of the feeding structure are excited which produces a wide impedance bandwidth (IBW). The introduction of FR4 branches in the air cavity helps to achieve a wider IBW of 48.3% (4.63–7.58 GHz). The E-field inside the air cavity acquires perturbation from the coupling of two dielectric patches (DP), which contributes to obtaining better CP performance. It can help achieve a wide axial ratio bandwidth of 35.3% ranging from 5.15 to 7.36 GHz for the proposed DPA. As the upper dielectric patch works as a director, a measured peak gain is increased to 8.47 dBic. Based on the multilayer PCB structure, the high permittivity dielectric patches loaded are packaged inside the FR4 substrates and fixed by branches. Therefore, a low-profile DPA with a height of 0.13 λ0 is obtained and exhibits self-packaging for DP elements.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
  • Q Factor-Based Electrically Small Antenna Radiation Efficiency Measurement
           Using the Wheeler Cap

    • Free pre-print version: Loading...

      Authors: Marwan Jadid;Christophe Delaveaud;Serge Bories;Anthony Bellion;
      Pages: 218 - 222
      Abstract: In this letter, a small antenna radiation efficiency measurement method is presented. The method utilizes the antenna quality factor, where it is a modification of the original Q factor method, amended by the loss Q factor of the antenna instead of the radiation Q factor. The method is verified for two kinds of antennas: the first is designed to operate at 868 MHz having a series resonance input impedance, and a second at 433 MHz having a parallel resonance input impedance. The method shows very high accuracy and prevent errors that may occur when using the conventional Wheeler cap method if the stored energy is not treated explicitly, which is considering the same imaginary part of the input impedance or input admittance for series resonance or parallel resonance, respectively.
      PubDate: Jan. 2023
      Issue No: Vol. 22, No. 1 (2023)
       
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
 


Your IP address: 3.236.70.233
 
Home (Search)
API
About JournalTOCs
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-