Recent Articles
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Compact High Selectivity Patch Antenna Under Triple-Mode Resonance via Loading Symmetrical Slots
19 December 2024 Mingli Sun, Qianwen Liu and Lei Zhu propose a compact filtering patch antenna on a single-layer substrate under triplemode resonance by loading two pairs of stepped slots. Initially, four straight slots are symmetrically etched along the radiation edges of a square patch radiator to reshape the radiation and resonant properties of its two higher-order TM02 and TM12 modes for bandwidth enhancement when maintaining the performances of the fundamental TM10 mode unchanged. Owing to the specific field distributions of the reshaped TM02 and TM12 modes, two radiation nulls can be produced nearby. In order to move the radiation nulls outside the desired passband for highly-sharpened wideband filtering radiation, the straight slots are then properly modified with their stepped ones in configuration.
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AMC-Based Miniaturized Waveguide With Reconfigurable Pass-Bands Below Cut-Off Frequency and Quasi-TEM Mode
18 December 2024 Vikrant Singh, Maryam Khodadadi, Mohsen Khalily, Rahim Tafazolli and Ahmed A. Kishk introduce an innovative miniaturized transverse electromagnetic (TEM) waveguide design, which is 60% smaller than conventional metal waveguides. The proposed waveguide offers two distinct electronically reconfigurable passbands well below the cutoff frequency. This has been achieved by using sidewalls composed of reconfigurable artificial magnetic conductors (AMC), optimized to operate at 3.51 GHz and 4.37 GHz. By replacing the metal sidewalls with an AMC structure, a TEM mode can be sustained within the confined space enclosed by the waveguide structure, which otherwise would not exist in a conventional metal waveguide. This eliminates typical cut-off frequency constraints that limit the size of conventional waveguides, thereby enabling a significant miniaturization of the waveguide design.
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Fluid Brilliance: Expanding the Horizons in MIMO Diversity Using Liquid Antenna
17 December 2024Viswanadh Raviteja Gudivada and Yi Huang present a six-port liquid dielectric resonator antenna designed to enhance diversity for Wi-Fi applications operating at 2.45 GHz, leveraging the fluidic properties of liquids. The proposed design incorporates both conventional and modified intrusive feeding mechanisms, specifically utilizing extended copper lines with vertical dielectric wall support. This arrangement is aimed at realizing six pattern and polarization-independent TM 02δ+1 , HEM y21δ+1 , HEM 122δ , HEM 222δ , HEM x21δ+1 , and HEM y12δ+1 higher-order modes belonging to the TM and HEM mode family.
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Compact Dual-Band, Dual-Circular Polarized Microstrip Antenna Array for K/Ka-Band Application
16 December 2024 Nohgyeom Ha, Gyoungdeuk Kim, Hyun-Cheol Bae and Sangkil Kim propose a novel dual-band and dual-circularly polarized microstrip antenna design for a small AAV or a low earth orbit (LEO) satellite applications at K/Ka-band. Utilizing arrow-shaped and T-shaped stubs, the proposed design ensures right-hand and left-hand circular polarization across two frequency bands. The design activates orthogonal modes (TM10/TM01 and TM30/TM21) simultaneously, leveraging arrow-shaped and T-shaped stubs to finely tune resonant frequencies. The dimensions of these stubs facilitate independent adjustment of each operational band, ensuring optimized antenna functionality across different frequencies.
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Electrically Large Complex Objects Recognition Based on Gated Recurrent Residual Network (GRRNet)
13 December 2024 Shangyin Liu, Lei Xing, Xiaojun Hao, Shuaige Gong, Qian Xu and Wenjun Qi propose a novel deep model based on gated recurrent residual network for electrically large complex objects recognition. It can fully exploit the data envelope information and temporal correlation to improve the system recognition performance. Electromagnetic (EM) scattering property measurements for electrically large objects are costly and time-consuming, affected by various environmental factors. The high-frequency approximate technique, namely the shooting and bouncing ray method (SBR), is introduced to quickly acquire high resolution one-dimensional range profile (HRRP) of electrically large complex objects. Both the corner reflector and the model car are measured to validate the accuracy of the SBR method. The method is employed to establish HRRP database for various vehicles in traffic scenarios. Deep learning can automatically study data deep features and show outstanding performance in various classification tasks.
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GPS Interference Cancelation Using Metamaterials
11 December 2024 Amir Jafargholi and Romain Fleury introduces a novel passive method and structure designed to mitigate unwanted interference at the antenna in conventional Global Positioning System (GPS) applications. In contrast to traditional approaches that typically utilize high-impedance structures with limited cancelation or antenna arrays employing null-steering techniques, which often result in increased complexity and cost, this study proposes the use of a single-element circularly polarized truncated microstrip patch antenna radially loaded by a magneto-dielectric metamaterial (MTM) structure. The problem is analytically examined, and an appropriate meta cell is chosen, designed, and fabricated.
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Reflective Metasurface for Multi-Band Polarization Conversion for Satellite Applications in 6G Networks
09 December 2024 Humayun Zubair Khan, Abdul Jabbar, Jalil Ur Rehman Kazim, Jamal Zafar, Masood Ur-Rehman, Muhammad Ali Imran and Qammer H. Abbasi introduce a reflective polarization converter based on metasurface, designed to offer both Linear-to-Linear polarization (LLP) and Linear-to-Circular polarization (LCP). The design comprises two periodically arranged split ring resonators with a slotted stripe that operate in the X, Ku, and K bands. The three discrete frequency bands demonstrate over 90% Polarization Conversion Rate for LLP for oblique incidence waves up to 45°. Additionally, the proposed converter achieves Left-Hand Circular Polarization (LHCP) in two sub-bands and Right-Hand Circular Polarization (RHCP) in two sub-bands for oblique incidence waves up to 45°.
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A Numerical Integration Method for Calculating the Bit Error Rate of Time-Modulated Array
04 December 2024 Kexin Wang, Jian Zhang, Gang Xin, Xue Lei, Jun Gao and Tianpeng Li present a novel approach for computing the bit error rate of time-modulated array using the Laplace inversion integral. They express the bit error rate as a Laplace inversion integral and select the integration path using the saddle point method. The integration result is obtained through numerical integration, and they derive the upper bound of the truncation error. The time-modulated array under consideration includes a single pole double throw switch array, which can independently exist in two states. This calculation method can be readily extended to time-modulated arrays with multiple states.
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A Millimeter-Wave Single-Bit Reconfigurable Intelligent Surface With High-Resolution Beam-Steering and Suppressed Quantization Lobe
03 December 2024 Aditya S. Shekhawat, Bharath G. Kashyap, Russell W. Raldiris Torres, Feiyu Shan and Georgios C. Trichopoulos present a 1-bit reconfigurable intelligent surface (RIS) operating at millimeter-wave frequencies that suppresses the undesired grating lobes encountered in binary phase modulation schemes and achieves high resolution beam steering. They incorporate fixed, random phase delays at each unit cell of the surface which breaks the periodicity of the phase quantization error and suppresses side lobes. Additionally, the random phase delays reduce the beam pointing error – a limitation of binary RISs - which can be beneficial in applications that require high resolution beam steering. The proposed topology allows for scalable RIS apertures that are compatible with printed circuit board (PCB) fabrication technology.
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Pushing Piezoelectric Transmitters to the MHz Regime
16 September 2024 Tristan A. Wilson, Srinivas Prasad Mysore Nagaraja, Stewart Sherrit, Devin Willey, Adam Wildanger and Darmindra D. Arumugam demonstrate that transmitters driven by piezoelectric resonators are capable of radiating quasistatic electromagnetic waves in the low frequency and very low frequency (LF and VLF) bands. These devices make use of the inverse piezoelectric effect to convert continuous-wave excitation into mechanical stress and strain that is oscillatory in nature. This is the first time that radiation has been shown with lithium niobate (LiNbO3) acoustically-driven transmitters operating in the MHz regime. The measured results from a line-of-sight spatial power drop-off experiment show great promise for physically realizable transmitters much smaller than the current state-of-the-art at these frequencies. These devices offer great potential to be used as compact low-power transmitters on platforms constrained by power and volume, such as drones, quadcopters, and microsatellites.
