Additional Articles
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Going Beyond a Simple RIS: Trends and Techniques Paving the Path of Future RIS
31 January 2024 Kinza Shafique and Mohammad Alhassoun review recent developments in reconfigurable intelligent surfaces (RIS) technology with a special emphasis on tuning techniques, hardware concepts, RIS empowered by artificial intelligence techniques, and applications for next generation of networks. Finally, a viewpoint on the difficulties and potential directions of intelligent metasurfaces are also presented.
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Ultra-Wideband Antennas for Wireless Capsule Endoscope System: A Review
17 January 2024 Ben Li, Yifan Wang, Junchi Zhao and Jingjing Shi present a comprehensive review of different ultra-wideband UWB antenna designs for wireless capsule endoscopy (WCE) system. In-body and on-body UWB antennas are classified according to the radiative performances and structure. Particular attention is also paid to the models used in simulation and experiment, as well as some key performance parameters and technologies in the process of antenna design. This extensive summary of UWB antennas for WCE systems will help to understand the prospects and challenges in this field.
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4×4 UWB Phased Array Antenna With >51° Far-Field Scanning Range for Wireless Power Transfer Application
02 January 2024 Adnan Basir Patwary and Ifana Mahbub design a single unit antenna to achieve ultrawideband (UWB) operation while maintaining high gain and unidirectional radiation pattern. It determines the array element spacing based on the theoretical modeling and simulation and measurement based validation to achieve the highest gain, minimum coupling coefficient, and lower side lobe level (SLL). In order to achieve beam steering, each 2×2 subarray is considered as a single quadrant thus dividing the 4×4 phased array antenna into four quadrants where all 16 single elements are individually fed. The far-field radiation beam is steered by controlling the phase difference between each quadrant.
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Analytical Equations for Designing Meander Line Antennas
01 January 2024 Ngu War Hlaing, Kamilia Kamardin, Yoshihide Yamada, Takuji Arima, Masaharu Takahashi and Naobumi Michishita note that the prior self-resonant equations in Meander Line Antenna (MLA) design included only inductive reactance (XC), neglecting the capacitive reactance (XD) equation. They address the gap by introducing new design equations, presenting a newly derived XD equation and an improved Q factor expression. The inadequacies of the existing Q factor equation, reliant on the radius of a sphere encompassing the antenna, are addressed by proposing a more fitting expression that incorporates antenna structural parameters using the ratio of reactance to resistance. The overview of existing design equations sets the stage for the introduction of these newly developed equations.
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Wideband/Dual-Band Dielectric Filtering Inverted-L Antenna With Reflective and Quasi-Reflectionless Radiation Nulls
29 December 2023 Wen Zheng, Shiyan Wang, Yin Li, Zai-Cheng Guo, Gang Zhang, Li Yang, and Roberto Gómez-García propose a class of dielectric filtering inverted-L antenna with reflective- and quasi-reflectionless-type radiation nulls to achieve wideband or dual-band operation. To this aim, a dual-function dissipative branch is exploited, which is in-parallel loaded at the feedline of the microstrip-fed dielectric inverted-L antenna. This absorptive branch, which is terminated in a grounded resistor, exhibits a quasi-complementary frequency response with regard to the one of the antenna. In this manner, it can mostly absorb the out-of-band RF-signal power not radiated by the antenna, hence creating quasi-reflectionless-type radiation nulls.
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True-Time-Delay Metasurface Assisted Broadband and Planarized Resonant Cavity Antenna
29 December 2023 Tayyab A. Khan and Alex M. H. Wong planarize a recently proposed resonant cavity antennas (RCA), which achieved a broad 3dB bandwidth of over 20% using a spherically modified ground (SMG), by replacing the SMG with a true-time-delay metasurface (TTD-MS) that mimics the both reflection phase shift and time-delay of the SMG over antenna’s entire operation bandwidth. They verify the proposed method through full-wave simulations and experimental measurements that demonstrate an impedance bandwidth (S11≤−10dB) of 32% and a 3dB-gain bandwidth of 21.3% (from 11.95 GHz to 14.8 GHz), with a peak gain of 17.5 dBi.
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Nyström-Type Technique for Electromagnetic Wave Scattering in Inhomogeneous Material, Plasma and Metamaterial Slabs
28 December 2023 John L. Tsalamengas present a simple, stable, and spectrally-accurate quasi-analytical method for studying the reflection, transmission, and radiation of EM waves in the presence of single-layer or multilayer material, plasma, or metamaterial slabs that are inhomogeneous along the normal to the slab interfaces. Our approach formulates the problem as a linear Volterra integral equation of the second kind, discretized using an entire-domain Nyström method with a high-order Gauss-type quadrature.
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A Dual-Polarized and Wideband Switchable Absorption/Transmission Frequency Selective Surface With Multispectral Functionality
25 December 2023 Huangyan Li, Youyi Feng, Minxin Zhao, Xiang Wang, Danilo Brizi, Xiaoxing Fang, Jun Hu, Boyu Sima, Zhiyuan Zong, Wen Wu and Agostino Monorchio develop a microwave absorption/transmission switchable frequency selective surface (A/T-SFSS) with enhanced multispectral functionality in the visible and infrared spectra. By controlling the flowing liquid medium (pure water in this work), efficient manipulation of two opposite states, absorption and transmission, can be achieved in the microwave frequency band with a wide switchable bandwidth. When functioning as a wideband absorber, the proposed A/T-SFSS exhibits an absorption rate over 90% from 6.50 GHz to 10.48 GHz.
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SIW Sub-Array Antenna With High Isolation Offering Dual-Polarized Monopulse Patterns
25 December 2023 Maksim Kuznetcov, Symon K. Podilchak and Mathini Sellathurai present a high isolation antenna which offers dual-polarization monopulse beam patterns, making the design suitable for polarization diverse or full-duplex (FD) systems. The single-layer structure is defined by a network of 2-D sub-arrays oriented in a cross-shape configuration using series-fed slots in substrate integrated waveguide (SIW) technology. Also, the proposed design exploits dual-differential feeding to achieve a −10 dB impedance matching bandwidth (BW) from 23.2 GHz to 25.4 GHz, and measured isolation values are more than 70 dB (peaking to about 90 dB) over this same operating range.
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Low-SAR and High-FBR Patch Antenna With Small Ground Size for Wearable Devices
14 December 2023 Shu-Wei Yu, Xiao Zhang, Qiong-Sen Wu, Lei Zhu, Tao Yuan and Qing-Hua Jiang propose a high front-to-back ratio (FBR) microstrip patch antenna with small ground plane size in this article. In order to suppress the serious back lobe brought by such a small ground, a hybrid loading technique consisting of coupled branch (CB) and resistor-loaded ground slot (RLGS) is introduced. Through the hybrid loading, extra magnetic currents on the ground are excited, by which the backward radiation of the original patch could be cancelled.
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Seamless Integration Technology for Filtenna Toward 5G/6G Wireless Communications
13 December 2023 Wei Hong, Zi-Jun Guo and Zhang-Cheng Hao review the design methodologies, operational principles, and implementation strategies of filtennas with illustrated examples in this paper. Whether in the context of 5G or 6G networks, base transceiver stations (BTS) require a substantial number of radio frequency (RF) transceiver chains and antenna array, particularly in mmWave frequency bands. It is known that bandpass RF filters between antenna elements and transceivers are key components for suppressing out-of-band spurs and interference. The single board seamless integration of transceivers and antennas has become a growing trend. It means there is no extra room for a large number of filters at mmWave bands, leading to the emergence of integrated designs that combine filtering circuitry with antennas, known as filtenna or filtering antenna.
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A Design of Dual-Polarized Composite Patch-Monopole Antenna With Reconfigurable Radiation Pattern
13 December 2023 Thanh Tung Phung, Son Xuat Ta, Khac Kiem Nguyen and Nghia Nguyen-Trong describe a design of dual-polarized composite patch-monopole antenna with reconfigurable radiation pattern. The design consists of a double differential-feed patch loaded with four vertical monopoles symmetrically. The monopoles are connected to or disconnected from the ground plane (GND) by changing the ON/OFF states of p-i-n diodes. By adjusting the connections between the monopoles and GND, the pattern reconfigurability (i.e., one widebeam and three narrow-beam modes) can be achieved for each polarization. The proposed antenna can switch the beam in two dimensions separately (xz− and yz− plane). The proposed antenna is characterized computationally and validated experimentally.
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An X-Band Linear-to-Circular Polarizer With High Refractive-Index Metamaterials
13 December 2023 Yat Sing To, Xue Ren, Quan-Wei Lin and Hang Wong present a novel wideband low-profile linear-to-circular polarizer based on high refractive-index metamaterials in the X band. The proposed design is a multilayer structure that is built from two kinds of metamaterial unit cells consisting of 4-H-shaped strips and 1-H-shaped strips. Combining the two unit cells realizes the flexible and independent control of the refractive index difference between two orthogonal E-field components and thus achieves a consistent 90-degree phase delay over a wide bandwidth.
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Compact Omnidirectional Circularly Polarized Antenna via Alford Loop and Wire-Patch Structure Combination
08 December 2023 Francesco Positano, Luca Santamaria, Robert Staraj and Leonardo Lizzi present a compact single-fed omnidirectional circularly polarized (OCP) antenna. The circular polarization is obtained by combining an Alford Loop (AL) and a Wire-Patch (WP) radiating structures, which are used to generate two orthogonal E-field components. The antenna exhibits a clear right-handed circular polarization (RHCP) with a dipole-like omnidirectional radiation pattern. A prototype has been realized using two FR-4 printed circuit boards (PCBs) and experimentally tested.
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The Path Reduction Factor for the Prediction of Rain Attenuation Affecting Short EHF Terrestrial Links
08 December 2023 Francesco Capelletti, Carlo Riva, Giuseppe Roveda and Lorenzo Luini Investigate the path reduction factor (PRF), a key element of semi-empirical rain attenuation statistics prediction models, to shed some light on its value for links shorter than 1 km. PRF is here calculated from simulations underpinned by the use of the Enhanced Synthetic Storm Technique (E-SST) to take into account the rain rate spatial distribution along the path. This novel approach, in contrast with the more customary one of inferring a PRF model from measurements, offers the advantage of avoiding considering any unwanted additional attenuation not due to precipitation, but typically linked to system-induced effects.
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High-Permittivity Dielectric Half-Loop Yagi-Uda Antenna With End-Fire Radiation
07 December 2023 Wen Zheng, Shiyan Wang, Mengjiao Tang, Gang Zhang, Wang Ren and Changzhou Hua propose a kind of half-loop Yagi-Uda antenna made of high-permittivity dielectric to realize end-fire radiation. As two typical materials with high permittivity, low-loss zirconia ceramic and liquid pure water are here employed for the proposed antenna to attain high radiation efficiency and support the characteristic of pattern reconfigurability, respectively. The thin dielectric waveguide with high permittivity is here used as the metal wire of conventional wire antennas, due to its traveling-wave radiation under TM01 mode. The different radiation characteristics of the electrically small loop and full-wave loop antennas are discussed.
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Characteristic Modes Analysis for Circularly Polarized 1-Bit Dual-Layer Transmitarray Design
07 December 2023 Francesco Alessio Dicandia and Simone Genovesi present a novel approach for designing a circularly polarized (CP) transmitarray (TA) by resorting to the characteristic modes analysis (CMA) . Two miniaturized dual-layer polarization-insensitive unit cells are tailored to provide the two copolar transmission coefficient phase states that act as a 1-bit spatial phase shifter in the TA. The exploitation of a pair of characteristic modes (CMs), radiating either right-handed CP (RHCP) or left-handed CP (LHCP) scattered field, is at the basis of the TA operation.
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Sparse Array Mutual Coupling Reduction
05 December 2023 C. Larmour, N. Buchanan, V. Fusco and M. Ali Babar Abbasi provide a concise overview of recent developments in sparse antenna arrays, with a specific focus on techniques for reducing mutual coupling in this article. It explores the concept and definitions of sparse arrays in different applications, highlighting their historical significance in antenna theory. The paper addresses the mutual coupling problem and presents reduced coupling geometrical configurations through illustrative examples. Various mutual coupling compensation techniques are discussed. The paper conducts a comprehensive comparison of multiple array design optimisation techniques, including genetic algorithm, covariance matrix adaptation evolution strategy, particle swarm optimisation, trust-region framework, Nelder-Mead simplex algorithm, interpolated Quasi-Newton, and classic Powell.
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Linearly Scanning Spoof Surface Plasmon Polaritons Leaky-Wave Antenna With High Scanning Rate
3 December 2023 Yue Wang, Shengying Liu, Chunsheng Guan, Hao Yu, Jinxiang Wang, Qun Wu, Changfei Zhou and Xumin Ding propose a wide-angle linearly scanning leaky-wave antenna (LWA) based on spoof surface plasmon polaritons (SSPPs) with a very high scanning rate. A sine curve period is introduced to construct the SSPPs transmission line in the form of a sine curve, which can transform the dispersion curve to the fast wave region to realize the desired dispersion properties for linearly high scanning rate LWA. The simulated results show that the proposed LWA achieves a scanning angle range of 109° over a narrow operation bandwidth of 7.73–8.13 GHz, implying high linearity, and a high scanning rate.
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Dual-Linearly Polarized Magneto-Electric Dipole Antenna for In-Band Full-Duplex Applications
01 December 2023 Qian Tan and Kwai-Man Luk propose a dual-linearly polarized (DLP) magneto-electric (ME) dipole antenna for the in-band full-duplex (IBFD) application. It is formed by ME dipoles with a shared central part, giving a compact and symmetrical antenna structure. It has four isolated channels, two for dual-LP transmitting (TX) and the other two for dual-LP receiving (RX). Due to the symmetrical structure, it can provide similar radiation patterns for both the TX and RX ports. Good isolation between any two of all four ports is obtained over a wide frequency range by modifying the antenna structure without introducing any additional complex feeding structures.
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User Effects on Mobile Phone Antennas: Review and Potential Future Solutions
29 November 2023 Igor Syrytsin, Gert Frølund Pedersen and Shuai Zhang explore the significant impact of human proximity on antenna design evolution in mobile communication from GSM to LTE and future 5G technologies. The paper offers a comprehensive view of the challenges posed by human interactions in current antenna designs, alongside modern solutions to mitigate these issues.
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Design of a Dual-Branch Resonator End-Launcher for Low-Loss WBAN Communications Using Wearable Waveguide Surfaces
28 November 2023 Maria El Bacha, Fabien Ferrero and Leonardo Lizzi propose a compact 30 mm x 30 mm dual-branch resonator end-launcher to enable communication through a waveguide surface manufactured with textile-compatible material at 2.4GHz. A 25 mm x 25 mm clearance zone area is respected for electronic component integration. The end-launcher topology uses a balanced dual-branch configuration to maximize electromagnetic coupling with the flexible waveguide surface. A design methodology is proposed to co-design the end-launcher and the waveguide surface.
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Wideband and Wide Beam Scanning Dual-Polarized Phased Array Antenna-in-Package Design for 5G Applications
27 November 2023 Haoran Zhang and Atif Shamim utilize multiple design strategies, such as employing stacked patch topology, electromagnetic band gap (EBG) structures, and the rotation of elements to obtain a true wideband performance. The single element of the phased array was a dual linear polarized stacked patch antenna with notched corners. Compared to a standard patch antenna, the bandwidth was enhanced by 15.3%. The undesired mutual coupling between elements was minimized by rotating nearby elements and introducing EBG structures between the adjacent elements.
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Bandwidth Enhancement of H-Plane MIMO Patch Antennas in Integrated Sensing and Communication Applications
20 November 2023 Lina Ma, Zijian Shao, Jun Lai, Changzhan Gu and Junfa Mao propose a low-cost compact decoupled bandwidth enhancement technique to address the high mutual coupling issue between wideband closely-spaced multiple-input and multiple-out (MIMO) patch antennas. The wideband decoupling property is realized by combining two decoupling circuits introduced by defected ground structure (DGS) and coplanar decoupling structure, respectively. An equivalent circuit is given to clarify the decoupling mechanism and provide physical insight. To validate the feasibility of the proposed design scheme, two prototypes of decoupled wideband patch arrays based on coplanar-fed and probe-fed schemes are simulated, fabricated, and measured in the 5.8 GHz ISM band, respectively.
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A Compact, Circularly-Polarized, Substrate-Integrated Waveguide, Millimeter-Wave Beamsteering System for 5G Mobile Terminals
17 November 2023 Khaled Al-Amoodi, Rashid Mirzavand, Mohammad Mahdi Honari, Jordan Melzer, Duncan G. Elliott and Pedram Mousavi propose a compact, circularly-polarized (CP), end-fire, 4×1 continuous beamsteering antenna array implemented using substrate-integrated waveguides for 5G mobile terminals. The purpose of this system is to complement the radiation patterns of planar phased arrays on the faces of a typical mobile terminal. The proposed system seamlessly integrates previously-presented antennas and polarizers, with adjustable phase shifters and a feeding network in a multi-layered, single stack, printed circuit board (PCB) for continuous beamsteering in a compact package.
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Dual-Band Shared-Aperture Base-Station Antenna Array With Dual Polarization Using Filtering Magnetoelectric Dipole Antenna
17 November 2023 Zhi Jing Xiao, Yun Fei Cao, Jia Sheng Lin, Yu Lan and Quan Xue present a dual-band shared-aperture antenna array using a filtering magnetoelectric (ME) dipole antenna for the application of mobile-communication base station. It is realized by interleaving a lower-band (LB) filtering ME dipole antenna operating from 1.7 to 2.8 GHz and four higher-band (HB) patch antennas in the band of 3.3-3.9 GHz. The filtering performance of the proposed ME dipole antenna is realized by U-shaped slots etched on the radiating arms and a cross-shaped microstrip line inside the aperture of the magnetic dipole, and used to realize a high cross-band isolation.
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A Slot-Connected Cavity Design With Corresponding Equivalent Circuit Model Analysis for Fully Metallic 3-D Vivaldi Antenna for Wireless Power Telemetry Applications
16 November 2023 Sunanda Roy, Karthik Kakaraparty and Ifana Mahbub present the design of fully metallic 3D Vivaldi antenna that can be used for wireless power transmission applications. The 3D antenna consists of 1) a tapered profile, 2) a rectangular cavity, and 3) a horizontal slot cut that is used as a transition between the cavity and the tapered profile. The proposed antenna design is fabricated using two distinct approaches, the first of which is a 3D metal additive manufacturing (AM scheme) with a sequential material layer addition technique. The second version is based on the CNC milling (CNCM) technique implemented by selectively removing material in a controlled way.
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On Performance Characterization of Harmonic Transponders
15 November 2023 Milan Polivka and Jeff Frolik show that harmonic transponders’ conversion loss is dependent jointly on interrogation power, interrogation frequency, and interrogation angle. This coupled nature of the device’s behavior necessitates performance metrics that capture these characteristics. They present a methodology to generically test these devices and propose metrics that capture the noted dependencies.
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Dual-Polarized Magneto-Electric Dipole for 5G 28-GHz Phased Array Applications
15 November 2023 Giuseppe Scalise, Emilio Arnieri, Giandomenico Amendola, Mohadig W. Rousstia, Sergio Pires and Luigi Boccia report a low-profile dual-polarized magneto electric (ME) dipole antenna configuration implemented on standard multilayer PCB technology. The proposed radiator is conceived for dual-polarized 28 GHz 5G phased array applications. Wideband operation is achieved by applying several low-frequency techniques which allow to fulfil the 5G requirements without increasing the dielectric core thickness. A 4×8 ME-dipole phased array is then designed, fabricated, and tested. The measured beam scanning range without the blindness in the E-plane is ±55° for the vertical polarization. Stable radiation patterns and a gain of up to 22 dBi are also achieved.
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A Lightweight Spherical Generalized Luneburg Lens Antenna With Low Cross-Polarization Over a Wide Range in Azimuth and Elevation
14 November 2023 Maral Ansari, Oskar Zetterstrom, Nelson J. G. Fonseca, Oscar Quevedo-Teruel and Y. Jay Guo present a novel dual-slant polarized three-dimensional (3D) periodic Luneburg lens with a diameter of 390 mm (4.6λ0 at 3.55 GHz). Copper-plated cubes with truncated corners are placed in a body-centered cubic (BCC) lattice and held together with layers of Rohacell foam. The sizes of the cubes are varied to realize the gradient refractive index (GRIN) profile of a generalized Luneburg lens at a low cost, with a low weight and loss.
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Enhancing Gain Through Optimal Antenna Element Distribution in a Thinned Array Configuration
08 November 2023 Michael Ortiz, Md Nazim Uddin, Marisol Roman Guerra and Elias A. Alwan present an array thinning approach for a 25-element antenna array arranged in a 5×5 grid at 5.4 GHz. Our goal is to eliminate a maximum number of antenna elements with minor gain loss and hence reduce the array size, weight, cost, and power requirements. Consequently, the space saved by the thinned array configuration presents opportunities to integrate additional antennas and hardware, allowing for a low-profile antenna-in-package. Our study showed that a 64% array reduction (from 25 to 9 probe-fed patch antennas) achieved an array gain comparable to a full array configuration.
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Dispersion Characteristics and Applications of Higher Order Isosceles Triangular Meshes in the Finite Element Method
08 November 2023 Yuhua Niu, Jinbo Liu, Wen Luo, Zengrui Li and Jiming Song proposed research shows that under the same order, the equilateral triangular meshes have the most uniform dispersion distribution. The isosceles triangles with equal base and height have more uniform dispersion error than the square meshes, while the maximum phase error is similar. Taking the rectangular waveguide as an example, the relative errors in the cut-off frequency are analyzed based on different meshes.
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Accurate Determination of Antenna Gain in the 300-GHz Band Using Amplitude Center Estimated From Electrooptic Near-Field Measurements
07 November 2023 Yuta Hayashi, Yu Katsuue, Yusuke Tanaka and Shintaro Hisatake propose and demonstrate an accurate antenna-gain determination method using the distance between the amplitude centers (ACs) of the antennas determined from the spatial phase distribution of the near field measured based on an electrooptic technique. Employing a WR-3.4 horn antenna, we show that at 286 GHz, the proposed method determines antenna gain with the same level of error even when the antenna separation distance is 1/5 shorter than that obtained using the conventional method that employs the physical distance between the antenna apertures in the Friis equation.
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Application of Coherently Radiating Periodic Structures for Feeding Subarrays in Limited-Scan Arrays
07 November 2023 Elizvan Juarez, Marco A. Panduro, David H. Covarrubias, Alberto Reyna and Carlos Del Rio present a new design technique to improve the reduction of phase shifters using sub-arrays and CORPS (coherently radiating periodic structures) technology. The CORPS network generates the values of cophasal excitation with reduced input ports. These values feed an optimal sub-arrays structure. Furthermore, fixed and variable amplifiers allow a low SLL (side lobe level) by using a raised cosine amplitude distribution along sub-arrays inputs. The theoretical model of CORPS-Subarrays, numerical and experimental results of several design cases are presented. The proposed design achieves a ±14° scanning range with a higher reduction of phase shifters than other techniques presented previously in the state of art.
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Efficient Calibration of Colocated MIMO Radar
06 November 2023 Ricard L. Grove and Jørgen Dall present a calibration technique that reduces the number of measurements required to obtain adequate calibration coefficients, compensating for all system imperfections that can be described in matrix form. This includes channel imbalance and mutual coupling under the assumption of minimum scattering antennas. The proposed technique estimates the calibration matrix for the transmit and receive array separately, by canceling out the element radiation pattern and effects from the other array through normalization.
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UTD-Type Solution of Physical Optics Approximation for Reconfigurable Intelligent Surface Modeled by a Continuous Planar Surface
02 November 2023 Xin Du, Chechia Kang and Jun-Ichi Takada propose a UTD-type solution of the physical optics approximation (PO) for RIS modeled by a continuous planar surface in a two-dimensional environment. The authors validate the proposal under different scenarios in an indoor environment (0.1−20 m) at the terahertz bands (100−300 GHz), by comparing them with those computed using the Fresnel approximation, the Fraunhofer approximation, PO, and the full-wave approach based on the method of moment (MoM). The simulated results show that compared to MoM, the proposal and PO achieve good accuracy with a smaller error of less than 1 dB, while the Fresnel and Fraunhofer approximations present imperfect accuracy with an error of larger than 1 dB in the near-field region.
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Increasing the Bandwidth of Wideband Antennas Using the Frequency Pulling Technique
02 November 2023 Anastasios G. Koutinos, Constantinos L. Zekios and Stavros V. Georgakopoulos address the limitation of frequency pulling technique (FPT) by (1) extending FPT to wideband designs, (2) using feeding points located at different planes, and (3) designing feeding networks as unequal power dividers. The networks not only simplify the design complexities associated with the traditional approach but also offer the capability to apply FPT to non-planar designs (e.g., 3D antenna configurations). To demonstrate the latter, they engineer a triangular tapered slot antenna, feeding it with a coupled microstrip line. As a result, the bandwidth of our modeled antenna increases from 34.51% to 78.25%, demonstrating excellent agreement between simulated and measured results.
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Electromagnetic Imaging System Calibration With 2-Port Error Models
01 November 2023 Seth Cathers, Joe LoVetri, Ian Jeffrey and Colin Gilmore introduce a novel approach to calibration that models the antennas and field propagation as 2-port networks (rather than scalars or a comprehensive model), for which common network theory and de-embedding techniques can be applied. The accuracy of the proposed 2-port method is experimentally tested against the scalar calibration technique on a 2D imaging system. The use of both metallic and dielectric calibration objects is tested, and the inversion performance is compared for the calibration techniques.
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Tuning-Range Extension Strategies for Varactor-Based Frequency-Reconfigurable Antennas
01 November 2023 Quoc Hung Dang, Nghia Nguyen-Trong, Christophe Fumeaux and Shengjian Jammy Chen present tuning range extension strategies for varactor-based frequency-reconfigurable planar patch antennas. The three tuning range optimization methods described in the paper include co-optimization of antenna dimensions and varactor properties, exploitation of multiple radiation modes, and reduction of parasitic capacitance. The first two strategies are emphasized by briefly reviewing two previously reported wide tuning range frequency-agile planar antennas.
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Decoupling for Millimeter-Wave Array Antennas Using Near-Field Shrinking Dielectric Superstrate
31 October 2023 Shengyuan Luo, Yiming Zhang, Peng Mei, Gert Frølund Pedersen, and Shuai Zhan propose a decoupling concept of near-field shrinking dielectric superstrate (NFSDS) for large-scale, wideband, and dual-polarized mm-wave arrays. An NFSDS with a thickness of 4 mm ( 0.32λ0 at 24 GHz) is mounted seamlessly above the array, which shrinks the near field of the array elements to reduce the space wave coupling while slightly increasing the surface wave coupling of the arrays. By loading a superstrate with a certain thickness and low permittivity, the total coupling of the mm-wave arrays is reduced significantly.
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2 × 2 Lens Array Antenna Using Square-Bottom Concave-Convex Lens in 300-GHz Band
17 October 2023 Bazilah Baharom, Yoshiki Sugimoto, Bakar Rohani, Kunio Sakakibara, Nobuyoshi Kikuma, Yoshihide Yamada and Nurul Huda Abd Rahman proposes a 2×2 lens array antenna composed of square-bottom lenses with a concave-convex lens shaping design to improve the uniformity and aperture efficiency. The measured results of the proposed 2×2 square-bottom concave-convex lens array antenna with a lens height of 9.74 mm achieved a boresight gain of 34.9 dBi, and the lowest sidelobe level observed was greater than −12 dB in the 300-GHz band.
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Synthesis of Plane-Wave Generator in 3-D Sphere Quiet Zone for Advanced Antenna Measurement by Hybridizing LSM and GA
11 October 2023 Haidong Chen, Weijun Zhong, Mu Tan, Zhaoling He, Ting Li, Quan Xue and Wenquan Che hybridize the Least Square Method (LSM) and Genetic Algorithm (GA) to efficiently synthesize the linear and planar array Plane Wave Generator (PWG) to create a 3-D Quiet Zone (QZ) with high performance for the antenna pattern measurement in a chamber with limited space. Based on the PWG with an 8-element linear array, the amplitude and phase deviations of 0.89 dB and 14.50° are obtained in a circular QZ with a diameter of 7λ , and that with an 8×8 -element plane array achieves 1.09 dB and 14.89° deviations in a 3-D sphere QZ.
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New Analysis and Design Techniques for Arbitrary Reactance Trap Dipoles
05 October 2023 Paul R. Winniford, Adrian L. Bauer, Hjalti H. Sigmarsson and Jessica E. Ruyle present a significantly revised analysis of a classic resonator loaded antenna– the trap dipole. The authors demonstrate in calculation, simulation, and measurement that trap dipoles antennas are not matched or resonant at the same frequency as the trap load resonance. The new analysis unites traditional high impedance trap loads with a wide variety of resonant and reactive loads to achieve multiband antenna performance with quasi-first order field distributions at the operating frequencies.
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Impact of 3-D Antenna Radiation Pattern in UAV Air-to-Ground Path Loss Modeling and RSRP-Based Localization in Rural Area
05 October 2023 Sung Joon Maeng, Hyeokjun Kwon, Ozgur Ozdemir and İsmail Güvenç investigate the impact of 3D antenna patterns on a UAV air-to-ground path loss model, utilizing datasets obtained from a measurement campaign. They conducted UAV experiments in a rural area at various fixed heights, while also characterizing the 3D antenna radiation pattern by using an anechoic chamber facility. By analyzing reference signal received power (RSRP) using path loss models that account for antenna patterns, the team observed that the measurement results, obtained at different UAV heights, aligned well with the two-ray path loss model when incorporating the measured antenna pattern.
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Low Sidelobe Pattern Synthesis of Array Antennas With a Triangular or Skew Lattice Using the IFT Method
05 October 2023 Will P. M. N. Keizer describes how the present 2D FFTs, direct and inverse, only applicable for rectangular lattices, can be modified in a simple way to make them suitable for the processing signals arranged along a triangular or skew grid. These two modified FFTs are subsequently implemented in the IFT method. The IFT method, updated in this way, is then very suited for the low sidelobe pattern synthesis of array antennas with a triangular lattice or skew lattice.
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A Global Optimization Method for Wideband and Small Supergain Arrays Design Using Artificial Neural Network
04 October 2023 Abdellah Touhami, Sylvain Collardey and Ala Sharaiha introduce an efficient approach for compact, wideband and supergain arrays design using artificial neural network (ANN) based optimization. The proposed method optimize at the same time the distance inter-elements of the array antenna, its input impedance as well as its directivity. Such global optimization considerably improves the performances of superdirective arrays in terms of gain, bandwidth and efficiency. The proposed method is used afterwards to synthesize a three-elements array using two different unit elements.
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Equivalent Circuit to Overcome Thévenin Limit for Receiving Lossy Dipole Antennas Motivated by the Poynting Streamline Analysis
27 September 2023 Junming Diao and Lu Liu propose to overcome the limitation of the Thévenin equivalent circuit in determining the loss and scattered powers when dealing with a lossy antenna that is near a large load impedance. They model and analyze the antenna directly as a receiver and visualize the flow of field energy around the antenna through generating streamlines of the Poynting vector field. Motivated by the Poynting streamline analysis, a new equivalent circuit for receiving lossy electric and magnetic dipole antennas is introduced in response to an incident plane wave, which addresses the shortcomings of the traditional Thévenin equivalent circuits.
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Compact and Broadband Substrate Integrated Dielectric Resonator Antenna Suitable for 5G Millimeter-Wave Communications
27 September 2023 Jie-Er Zhang, Qinfang Zhang, Wei Qin, Wen-Wen Yang and Jian-Xin Chen propose a compact and broadband substrate-integrated dielectric resonator antenna (SIDRA) suitable for 5G millimeter-wave band applications. Four operating modes from three resonators, including TE111 and TE131 modes from the DR, slot mode from the H-shaped feeding slot, and patch mode from the inserted ring patch, are excited to achieve a bandwidth of 61.9% (24-45.5 GHz) with a compact size of 0.37λ0×0.37λ0×0.125λ0.
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Excitation Diversity in Adaptively Thinned Arrays for Microwave Sensing Applications
26 September 2023 Sandra Costanzo and Giovanni Buonanno propose an excitation diversity technique included in thinned arrays design to overcome the unacceptable discrepancy between the actual radiation pattern and the desired one, especially for small to medium-sized arrays, after reducing the complexity of the feeding network. Data distributions achieved with the above approach are averaged to obtain potential high-quality final images. Moreover, the proposed methodology can be easily implemented in real-time adaptive arrays.
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Design of Compact and High Isolation Dual-Polarized Antenna Array via Plasmonic Meta-Structure
20 September 2023 Zhang Wen Cheng, Shimeng Wang, Yue Teng Chen, Ji Ran Chen, Jing Cheng Liang, Feng Gao, Shuai Luan, Xin Liu, Hui Feng Ma and Tie Jun Cui propose a compact and high isolation dual-polarized antenna array based on plasmonic meta-structure operating at 2.58 GHz. The compact principle of the dual-polarized antenna is mainly based on spoof surface plasmon polariton (SSPP) radiation patch to support SSPP modes, which is fed by spatially coupled excitation. The cross-polarization coupling between two polarization ports can be improved to below −32 dB, showing high isolation characteristics.
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A Quad-Polarization and Beam Agile Array Antenna Using Rat-Race Coupler and Switched-Line Phase Shifter
18 September 2023 Maodudul Hasan, Eisuke Nishiyama and Ichihiko Toyoda propose a quad-polarized microstrip array antenna with beam steering capability. The proposed antenna consists of two patch elements, one rat-race coupler, and two 90° switchable phase shifters. With the aid of just four PIN diodes, the two 90° phase shifters can provide four different diode arrangements for each port of the rat-race coupler. The array elements are excited by using orthogonal feed lines. Due to the combination of the rat-race coupler and phase shifters, different phase conditions are generated between the patch elements or orthogonal modes of the patches.
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A Multi-Port Pattern Diversity Antenna With High Isolation
18 September 2023 Nghia Nguyen-Trong and Christophe Fumeaux propose a pattern-diversity antenna with 7 ports for multiple-input multiple-output (MIMO) applications. Orthogonal modes are utilized to achieve high isolation among all 7 ports in a relatively compact shared volume. As distinguishing feature from previous works, the concept of tripolarization is generalized, allowing to design antennas with a large number of orthogonal patterns in a single multi-port device.
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Ultra-Wideband Tightly Coupled Dipole Array Fed by a Tapering Meandered Balun
15 September 2023 Matthew W. Nichols, Michail O. Anastasiadis, Malcolm E. Taaffe, Elias A. Alwan and John L. Volakis present an ultra-wideband (UWB) phased array operating from UHF to C-bands (0.14 to 5.85 GHz). This design employs an integrated, compact tapered spline balun in conjunction with a triple-layer semi-resistive frequency selective surface (FSS) network. Notably, the integration of the meandered balun within a dual-polarized tightly-coupled dipole array (TCDA) allowed for a contiguous bandwidth of 40:1 with VSWR < 2.5 at broadside.
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Broadband Multi-Shaped Metasurface Circularly Polarized Antenna With Suppressed Non-CP Radiation Modes
13 September 2023 Nathapat Supreeyatitikul, Titipong Lertwiriyaprapa, Nonchanutt Chudpooti, Monai Krairiksh and Chuwong Phongcharoenpanich propose a multi-shaped metasurface broadband circularly polarized (CP) patch antenna with parasitic elements for 5G new radio (NR) applications. The proposed metasurface CP patch antenna comprises triple-layered substrates without air gap. The upper layer sits with multi-shaped metasurface elements and parasitic patches. The middle layer consists of an L-shaped slot functioning as the ground plane, and the lower layer contains a microstrip and a fan-shaped stub functioning as the feed line. The proposed metasurface CP patch antenna with parasitic elements is evaluated using characteristic mode analysis (CMA).
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Synthesis of Symmetric, Two-Element Biomimetic Antenna Arrays Using Singular Value Decomposition
04 September 2023 Son Vu, Saeid Jamilan, Barry D. Van Veen, Hung Luyen and Nader Behdad present a method for determining the four-port S-matrix of the external coupling network (ECN) for symmetric, two-element biomimetic antenna arrays (BMAAs) by employing singular value decomposition (SVD). The presented approach greatly facilitates the synthesis procedure of symmetric, two-element BMAAs and allows all possible scattering matrices of a four-port network realizing the ECN to be easily determined.
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Efficient Optimization Design of Large Circular Phased Arrays With Low Sidelobes for Beam Scanning
04 September 2023 Yi-Xuan Zhang, Tian-Ye Gao, Li Zhang, Yong-Chang Jiao and Tao Ni propose an efficient optimization design method for large circular phased arrays with low sidelobes for beam scanning. Based on the differential evolution algorithm (DE), each layer’s radius and element number are optimized to obtain the required element arrangement. If the main beam scans from the Z-axis, it is difficult for designers to find the maximum sidelobe.
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Low-Cost Hybrid Implementation of an Efficient E-Band Array Based on Stepped and Ridged Slots
01 September 2023 Sherif R. Zahran, Emilio Arnieri, Stefano Moscato, Matteo Oldoni, Dario Tresoldi, Giandomenico Amendola and Luigi Boccia present an 8×8 waveguide antenna array composed of stepped and slotted radiators for E-band applications. The proposed array architecture, including the feeding network, can be realized through the integration of a single metallic block adhered with an additional top photo-etched sheet. This approach effectively reduces manufacturing complexity, resulting in a low-cost solution that can be easily fabricated using standard market-ready technologies.
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Multi-Mode Antennas for Ultra-Wide-Angle Scanning Millimeter-Wave Arrays
28 August 2023 Gabriele Federico, Zhe Song, Guilherme Theis, Diego Caratelli and A. Bart Smolders present a novel multi-mode millimeter-wave antenna array with enhanced scan range and reduced scan losses. The individual array element consists of a differentially fed microstrip patch on top of which a cylindrical dielectric resonator is integrated. The radiation pattern of the antenna element can be reconfigured by changing the phase offset between the feeding ports of the patch and the dielectric resonator to excite two distinct radiating modes.
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A Dual-Band Dual-Polarized Base Station Antenna Array With Isolation Enhancement
28 August 2023 Lei Ge, Yinhui Wang, Mingye Du, Weiyang Liu and Yue Zhao design a dual-band dual-polarized antenna with isolation enhancement. The proposed antenna operates in the frequency range of 3.4–3.6 GHz and 4.8-5 GHz, where the center frequency of the high band (HB) is 1.4 times that of the low band (LB). Two radiating patches are placed in different layers to create the two distinct resonances and the bottom patch which is shorted to the ground by four metal posts acts as the ground for the top patch antenna. A metal wall is introduced between LB feeding probes to enhance the polarization isolation to more than 25 dB. Complementary split-ring resonator (CSRR) structures are etched on the feedlines to improve the cross-band isolation to over 25 dB.
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Near-Field Calibration Methods for Integrated Analog Beamforming Arrays and Focal Plane Array Feeds
11 August 2023 Roel X. F. Budé, Kevin A. P. Van Hastenberg, Ulf Johannsen and A. Bart Smolders propose a near-field calibration method for millimeter-wave analog beamforming array antennas and focal plane array antennas. Nonidealities of the beamformer integrated circuits with vector modulators are taken into consideration, and a way to reduce the measurement set for vector modulators with high resolution is proposed. This method is both practical and achieves a good calibration as evidenced by measurements of the radiation patterns, and it is suitable for use in an automated factory calibration setup.
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Coupled Array of Diverse Elements for Wideband High Spherical Coverage
10 August 2023 Quangang Chen, Veli-Pekka Kutinlahti, Jaakko Haarla, Anu Lehtovuori and Ville Viikari propose a flexible cluster array concept utilizing diverse antenna elements and the mutual coupling among them to improve the spherical coverage. This innovative approach can not only enhance the impedance matching but also improve the beamforming performance across a wide frequency band by adjusting excitation amplitudes and phases. Equations are derived to achieve specific objectives such as minimizing the total active reflection coefficient or maximizing the realized gain of an antenna array.
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Analysis and Experimental Demonstration of Reflectarray Antennas in Quasi-Regular Lattices
09 August 2023 Borja Imaz-Lueje, Juan Córcoles, Marcos R. Pino and Manuel Arrebola present investigations on reflectarray antennas using non-periodic element distributions. The study involves the analysis and design of two reflectarrays based on quasi-periodic lattices with rectangular and pentagonal profiles, whose performance is compared with equivalent reflectarrays comprised of regular grids of elements. The characterization of these antennas is performed using a tailored analysis technique for reflectarrays with periodical and quasi-periodical grids. The proposed technique uses the Method of Moments under local periodicity conditions (MoM-LP) to compute the field on the surface of each cell and then the far field radiated by the aperture.
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Shared Impedance Noise Coupling in Radio Receivers
08 August 2023 Yihong Qi and Yunlong Luo elucidates a shared impedance noise coupling mechanism, which sheds light on how passive antennas can introduce excess noise into the wireless system. This article introduces the general theory of antenna noise temperature, providing an explanation for the mechanism of noise coupling through a shared impedance path. Additionally, a mathematical expression for radiated sensitivity is presented.
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Uncertainty Analysis Methodology for Measurements of Dynamic Millimeter-Wave Channels
01 August 2023 Robbert Schulpen, A. Bart Smolders, Ulf Johannsen, and L. A. Bronckers present a novel uncertainty analysis methodology to quantify uncertainties of condensed parameters in measurements of dynamic millimeter-wave channels. The bandwidth limitation and multipath threshold are identified as important impairments. Therefore, the methodology provides three uncertainty metrics for condensed parameters, namely a standard uncertainty to quantify the impact of random variations; a bias due to the multipath threshold; and a total bias including the impact of the bandwidth limitation.
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End-to-End Channel Modeling and Generation Software Based on Statistical mmWave Channel Model
28 July 2023 Yusuke Koda, Ruiting Ouyang and Hiroshi Harada develop an end-to-end software to automatically perform channel modeling and simulation with statistical validity just by inputting measured power profiles. The developed software involves comprehensive algorithms to reach channel parameter extraction, such as multi-path component (MPC) extraction, MPC clustering, and maximum-likelihood estimations for respective parameters. They highlight that channel parameters reported by the IEEE 802.15.3c task group (TG) do not necessarily fit the original power profiles, highlighting the need to examine the validity of the existing parameters by leveraging the developed software.
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Design of a Compact 4-Element GNSS Antenna Array With High Isolation Using a Defected Ground Structure (DGS) and a Microwave Absorber
25 July 2023 Abdullah Madni, and Wasif Tanveer Khan presents a compact (125 mm diameter) wideband 4-element antenna array with a high isolation level for global navigation satellite system (GNSS) applications. The array consists of four right hand circularly polarized (RHCP) single feed rectangular patch antennas that can cover BeiDou B1 band (1561.098 MHz), GPS L1 band (1575.42 MHz), Galileo E1 band (1575.42 MHz) and GLONASS G1 band (1602 MHz) of the GNSS upper L-band (1559 - 1610 MHz). The proposed array has a wide frequency bandwidth of 80 MHz with an axial ratio of less than 3 dB. The patch elements are designed on a substrate which has a high dielectric constant to achieve a compact size.
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A Study on mm-Wave Propagation in and Around Buildings
20 July 2023 Leonardo Possenti, Marina Barbiroli, Enrico M. Vitucci, Franco Fuschini, Mattia Fosci, and Vittorio Degli-Esposti analyze in depth the peculiar characteristics of mm-wave propagation, joint measurement and simulation campaigns in indoor and outdoor microcellular environments. The investigation highlights that the assumption that mm-wave NLoS connectivity is hardly feasible is not necessarily true as significant reflections, scattering and even transmission mechanisms can provide good NLoS coverage in the considered indoor and outdoor scenarios. This is also reflected in the limited angle-spread differences between LoS and NLoS locations in some cases.
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Dual-Port RHCP Compact Antenna at 868 MHz Using a 120° Hybrid Coupler
19 July 2023 Fabien Ferrero, and Le Huy Trinh present the design of a compact dual-port circularly polarized antenna based on the new coupler topology. The antenna can radiate a right-hand circular polarization (RHCP) in two opposite directions depending on the input port. In the proposed structure, the radiating system has three inverted F antennas connected to a 120° hybrid coupler. The modeling and design of the 5-ports hybrid coupler are described and experimentally validated.
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Compact U6G Massive MIMO Antenna Arrays With Double-Layer Partial Reflective Decoupling Layers for Mutual Coupling Suppression
18 July 2023 Ting Liu, Jiayue Jiang, Luyu Zhao, Ge Zhao, Huiqing Zhai, Yuan-Ming Cai, Teyan Chen, and Wenwei Xu utilize a systematic decoupling strategy of two partial reflective decoupling layers (PRDLs) and dummy decoupling probes (DDPs) to suppress the complicated couplings in a ±45° dual-polarized, compact antenna array operating at Upper 6 GHz (U6G, 6425–7125 MHz) bands. Finely engineered neutralization electromagnetic waves are introduced by two PRDLs to counteract the original couplings. Two layers of PRDLs are placed above the antenna array in a step-by-step manner to gradually cancel out several major couplings while DDPs are placed around the antenna elements to reduce the remaining couplings.
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Wide-Angle Beam Scanning Phased Array Antennas: A Review
18 July 2023 Ming Li, Shu-Lin Chen, Yanhui Liu, and Y. Jay Guo investigate and discuss several challenges that hinder wide-angle beam scanning (WABS) for conventional phased array antennas (PAAs), including the strong mutual coupling, narrow beamwidth of the element antenna, etc. in this review. They then review and summarize a variety of innovative techniques to overcome these challenges, and analyze potential research gaps of WABS PAAs for future emerging applications.
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Airborne Reflector-Based Ground Penetrating Radar for Environmental and Archaeological Studies
17 July 2023 Zayed Mohammad, and Andrew M. Chrysler design and propose a wideband airborne reflector-based ground penetrating radar (GPR). It consists of 15 discrete panels, each panel supported by a single multi-rotor unmanned aerial vehicle (UAV). A lightweight, wideband Vivaldi antenna was developed as the feed structure. The antenna operates within the frequency range of 100–500 MHz and has a bandwidth of 387 MHz. The proposed antenna will possess a penetration depth of 2 m.
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Feed Integration and Packaging of a Millimeter-Wave Antenna Array
17 July 2023 Matthew W. Nichols, Stavros Koulouridis, Satheesh B. Venkatakrishnan, Elias A. Alwan, and John L. Volakis present and demonstrat a novel approach for integrating a wideband vertically fed antenna array at Millimeter-Wave (mm-Wave) frequencies. Specifically, a novel cost-effective Antenna-In-Package (AiP) fabrication approach is presented, then a prototype operating from 55 GHz to 64 GHz is built while predicted performance is verified via measurements. This approach relies on separating fabrication into- the array and
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A 3-D Printed Ultra-Wideband Achromatic Metalens Antenna
17 July 2023 Yu-Xuan Xie, Geng-Bo Wu, Wen-Qiang Deng, Shu-Yan Zhu, and Chi Hou Chan propose a millimeter-wave achromatic metalens antenna using three-dimensional (3D) printing technology to reduce the dispersion effect and enlarge its bandwidth. The proposed ultra-wideband achromatic metalens antenna consists of a convex-liked metalens (VLM) and a concave-liked metalens (CLM) integrated as a metalens group.
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A Technique to Realize Aperture Coupled Microstrip Patch as a Truly Low Cross-Polar Antenna by Mitigating the Major Issues Over its Skewed Radiation Planes
14 July 2023 Sk Rafidul, Chandrakanta Kumar, and Debatosh Guha address and resolve the limitation of the low cross-polarized (XP) radiations of aperture-fed microstrip patch by introducing a pair of additional printed loops adjacent to the radiating patch.Detailed investigations leading to the design insight have been presented. A C-band rectangular patch promises as much as 7 dB suppression in the diagonal plane XP level keeping the overall performance across the principal radiation planes unchanged.
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Antenna Design for the Arctic Weather Satellite Microwave Sounder
14 July 2023 Roland Albers, Anders Emrich, and Axel Murk propose an antenna design for the Arctic Weather Satellite (AWS), a prototype mission for an operational constellation of microwave sounders, complimenting existing meteorological sounders. The AWS is a microsatellite with a single cross-track scanning radiometer operating in the 54, 89, 183 and 325 GHz bands. Due to the small platform size, the core design focus of the radiometer’s quasi-optics is less complexity and a more compact setup than comparable spaceborne microwave sounders. The main challenge for instrument performance is that only one of the four horns can be located in the focus of the scanning reflector. Consequently, scan angle dependent spillover variations and beam asymmetries can occur. This paper details the simulation and optimisation efforts of the quasi-optics to minimise the aforementioned effects.
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Tuning the Angular Characteristics of Biomimetic Antenna Arrays
11 July 2023 Ines Dorsch Dominik Schwarz, Sarah Forster, and Christian Waldschmidt present the concept and the design process of a tunable Biomimetic Antenna Arrays (BMAA). By electronically tuning varactor diodes, such an array can adapt its angular characteristics depending on the direction-of-arrival (DoA) and signal strength of a radar target. The theoretical requirements for the desired task are examined with general S-parameter simulations. Extensive circuit simulations of a proposed architecture unveil a variety of achievable designs of tunable BMAAs. Radar measurements of different implementations in the 77 GHz range and the theoretical analysis are in good agreement.
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Receive Mode Time-Modulated Antenna Array Incorporating Subsampling—Theoretical Concept and Laboratory Investigation
07 July 2023 Edward A. Ball, Sumin David Joseph and Alan Tennant present an eight element Subsampling Time Modulated Array (STMA) operating in receive mode with a carrier at 2.4 GHz using bespoke Radio Frequency (RF) hardware. Each STMA cell incorporates subsampling functionality, with the sampling frequency significantly below the carrier frequency and requiring minimal additional hardware. By using this concept, the hardware required for a receiver incorporating an antenna array can be reduced and costs saved. STMA design equations and architecture strategies are presented, and a prototype hardware demonstrator is introduced.
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A Dual Wide-Band Mushroom-Shaped Dielectric Antenna for 5G Sub-6-GHz and mm-Wave Bands
05 July 2023 Reza Shamsaee Malfajani, Hamed Niknam, Sampada Bodkhe, Daniel Therriault, Jean-Jacques Laurin and Mohammad S. Sharawi present the design and implementation of a dual wide-band mushroom-shaped antenna. The antenna consists of a cylindrical dielectric resonator (cDRA), a cylindrical dielectric rod as a waveguide (cDR), and a dielectric lens (DL). The cDRA in conjunction with the DL acts as a sub-6-GHz antenna. At the mm-wave band, the small cDR acts as a waveguide, which transfers the wave from the feed toward the larger cDRA and the DL in order to produce a high gain.
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A Diffusion Model for Multi-Layered Metasurface Unit Cell Synthesis
04 July 2023 Chen Niu, Mario Phaneuf, and Puyan Mojabi propose a deep learning approach based on a diffusion model to yield metasurface unit cell designs. This method takes desired two-port scattering parameters along with the frequency of operation in an attempt to synthesize three-layered metasurface unit cells. The core of this approach lies in casting the three-layered unit cell synthesis process as conditional three-channel binary image synthesis. The conditions are governed by the desired scattering parameters at a given frequency whereas the binary nature implies the presence and absence of metallic traces.
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A Deep Learning-Based Approach to Design Metasurfaces From Desired Far-Field Specifications
04 July 2023 Chen Niu, Mario Phaneuf, Tianke Qiu and Puyan Mojabi develop a deep learning neural network model in conjunction with a method to incorporate auxiliary surface waves for the macroscopic design of transmitting metasurfaces. The main input to the neural network model is the user-defined desired far-field specifications. This network is used to calculate the required tangential electromagnetic fields on the metasurface. These fields will then be augmented by incorporating auxiliary surface waves along the metasurface for power redistribution to satisfy the requirement for having lossless and passive metasurfaces.
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Statistical Evaluation of the Role of GNSS Signal Propagation Orientation in Low-Latitude Amplitude Scintillation Severity
30 June 2023 Alison Moraes, Jonas Sousasantos, Bruno J. Affonso, Paulo R. P. Silva, Eurico R. De Paula and João F. G. Monico perform an analysis considering aspects of the orientation of the propagation of the radio signals through the plasma bubbles structures to evaluate how this geometry can affect the scintillation profile. The dataset covers five months of records from three stations over the Brazilian region during the last solar cycle maximum. The initial results indicate that propagation paths fully aligned are consistently related to larger values of S4 and more severe scintillation.
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Physics-Based Coherent Modeling of Long-Range Millimeter-Wave Propagation and Scattering in Rain
12 June 2023 Behzad Yektakhah and Kamal Sarabandi present a fast and accurate numerical method for phase coherent modeling of wave propagation and scattering in random media, like rain. In this approach, the random medium is divided into sufficiently large finite slabs and each slab is modeled as a network with multiple input/output ports where ports represent rays with different polarizations propagating in different directions entering and leaving the slabs. The proposed method considers multiple scattering among all scatterers and thus the entire physics of wave-particle interactions is accounted for.
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Bandwidth Enhancement of Low-Profile Metasurface Antenna Using Nonuniform Geometries
08 June 2023 Hayden A. Banting and Carlos E. Saavedra investigate artificial magnetic conductor metasurface antennas using a robust, surrogate-assisted, differential evolution optimization technique. Using a uniform metasurface array configuration as a starting point, multiple array configurations are parameterized and the differential evolution optimizer yields nonuniform array geometries exhibiting wideband performance. Two prototypes are fabricated and characterized to experimentally confirm the advantages of proposed designs.
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Post-Fabrication Technique to Manage Material Variations in 3-D Printed Microstrip Antenna Substrates
08 June 2023 Zere Iman, Zubair Akhter, Yiyang Yu and Atif Shamim present a post-fabrication technique capable of compensating for variations in the εr of 3D printed substrates, focusing on microstrip patch antennas (MPAs). The proposed technique, suitable for correcting the fr of a single microstrip patch antenna, uses either a single blind via or an array of vias in the 3D-printed substrate. Two MPAs were fabricated on a 3D-printed substrate and it is shown that their fr values can be shifted upward or downward by following the proposed guidelines.
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3D Printed Hemispherically Radiating Antenna for Broadband Millimeter Wave Applications
23 May 2023 Lukas Engel, Danti Khouri, Konstantin Lomakin, Andreas Hofmann, Micha Kleinlein, Ingrid Ullmann, Martin Vossiek, and Gerald Gold present a 3D printed monolithic antenna for millimeter wave-sensing applications with a full hemispherical coverage. The antenna is designed as an ensemble of a waveguide horn antenna and a differentially fed dipole antenna. The slotted waveguide approach was utilized to improve the manufacturing quality on the waveguide inside.
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Reflectarray Feeds Augmented With Size-Reducing GRIN Lenses for Improved Power Handling and Aperture Efficiency
19 May 2023 Eric B. Whiting, Galestan Mackertich-Sengerdy, Ryan J. Chaky, Colin A. Mussman, Sawyer D. Campbell, Pingjuan L. Werner, and Douglas H. Werner demonstrate highly effective approaches for optimizing GRIN lenses to achieve different design objectives including high gain radiation with a compact feed as well as improved aperture efficiency and power handling. Additive manufacturing is employed to fabricate the lenses, and measured results agree well with simulations.
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Analytic Approximation of In-Body Path Loss for Implanted Antennas
15 May 2023 Mingxiang Gao, Zvonimir Sipus, and Anja K. Skrivervik present a simplified model of an implanted antenna that provides closed-form approximate expressions to estimate EM radiation from the implant. In particular, they extend the expressions for the reactive near-field losses to both deep and shallow implants, by taking into account the implantation depth.n The proposed approximate method is verified by comparing the results obtained with the full-wave simulations in the case of a miniature implanted antenna, and with both simulated and measured results from two practical examples found in the literature.
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3-D Printable Synthetic Metasurface to Realize 2-D Beam-Steering Antenna
10 May 2023 Foez Ahmed, Touseef Hayat, Muhammad U. Afzal, Shiyu Zhang, Karu P. Esselle, and William G. Whittow present highly radio-frequency (RF) transparent phase gradient synthetic metasurfaces made of sub-wavelength-sized 3D printable meta-atoms with tailored permittivity that cannot be achieved with off-the-shelf, commercially available materials. The synthesized meta-atoms design uses one dielectric block of PREPERM ® ABS 1000 material with air and metallic inclusions to make low- and high-permittivity materials. The inclusions’ size and height are varied to achieve a complete phase range from 0 to 360°, while maintaining transmission magnitudes greater than −3.0 dB.
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A 3D-Printed Encapsulated Dual Wide-Band Dielectric Resonator Antenna With Beam Switching Capability
09 May 2023 Reza Shamsaee Malfajani, Hamed Niknam, Sampada Bodkhe, Daniel Therriault, Jean-Jacques Laurin, and Mohammad S. Sharawi present the concept of encapsulated dielectric resonator antennas (E-DRAs). In E-DRAs, smaller-sized DRAs with a specific permittivity is embedded inside a larger DRA with a lower permittivity allowing for simultaneous efficient radiation at two widely separated and widely covered frequency bands. The proposed E-DRAs cover both the sub-6-GHz band (with a large size DRA) and mm-wave band (with smaller sized DRAs) for 5G and beyond applications.
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3-D Printed All-Dielectric GRIN Lens Antenna With an Integrated Feeder
05 May 2023 Anastasios Paraskevopoulos, Francesca Maggiorelli, Ilir Gas Hi, Cristian Della Giovampaola, Matteo Albani, Stefano Maci present the design, fabrication, and experimental verification of a new type of Graded-index (GRIN) lens antenna with an integrated feeder. The continuously varying refractive index distribution is chosen appropriately to offer the rays collimation at the lens aperture. It is practically implemented by varying the material density in a host medium, thus realizing a new type of all-dielectric high gain antenna, entirely using 3D printing. This solution can find application to high gain wireless communication and measurement systems.
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Planar Array Subarray Division Method in Microwave Wireless Power Transmission Based on PSO&K-Means Algorithm
27 April 2023 Qian He Zhang and Zhao Yang Shen propose a clustering algorithm based on a combination of the particle swarm algorithm and the K-means algorithm for the subarray partitioning of planar arrays to address the problem of maximizing beam collection efficiency in microwave wireless power transmission. The effectiveness of the proposed method is evaluated by integrating the beam collection efficiency with parameters such as the receiving area and the size of the planar array.
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Fully Printed 3-D Antennas With Wideband Radiation Isotropy Based on Annular Currents Models
02 May 2023 Ruiqi Wang, Kirill Klionovski and Atif Shamim propose a theoretical model based on annular ring currents to synthesize quasi-isotropic antenna radiation patterns. The theoretical model shows that wideband radiation isotropy can be achieved by optimizing the combination of azimuthal currents. We subsequently present spherical and cubical ESA designs that achieve measured wide impedance and radiation isotropy bandwidths exceeding 10% for the GSM900 band.
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Circularly-Polarized Patch Antennas With Enhanced Bandwidth Based on Capacitively Coupled Orthogonal Patch Radiators
02 May 2023 Qiong-Sen Wu, Xiao-Yu Tang, Xiao Zhang, Lei Zhu, Gary Zhang and Chun-Bing Guo propose circularly-polarized (CP) patch antennas with enhanced bandwidth based on capacitively coupled orthogonal patch radiators Several patch radiators are alternately arranged one by one along the x - and y -direction, producing orthogonal currents and far fields. The adjacent patch radiators are coupled to each other and the coupling structure not only contributes to power distribution but also introduces 90° phase shift for circularly-polarized radiation.
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A Concept of Advanced Design Governed by Theoretically Predicted Current Distributions on the Ground Plane Beneath an Aperture-Fed Microstrip Antenna
02 May 2023 Debi Dutta, Debatosh Guha and Chandrakanta Kumar explore a way of mitigating near field issues based on theoretical analysis and propose a simple strategic approach to reform the same for a rectangular patch. A representative design, theoretical justification, and experimental studies with an S-band prototype have been presented. XP suppression by 11dB has been experimentally achieved in the diagonal (D-) plane with no considerable changes in its H- or E-plane. That eventually attains an overall XP discrimination by nearly 27dB from the perspective of 3D radiation scenario.
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Uniform Analysis of Multipath Components From Various Scenarios With Time-Domain Channel Sounding at 300GHz
02 May 2023 Johannes M. Eckhardt, Alper Schultze, Ramez Askar, Tobias Doeker, Michael Peter, Wilhelm Keusgen, and Thomas Kürner present a uniform and collaborative data evaluation of measurement sets from two different time-domain channel sounders. The channels show a great variety of characteristics depending on the scenario, the line-of-sight condition and the signal-to-noise ratio requirements of the prospective communication system. The extracted multipath components are published as research data for future analytical studies and simulations in relevant scenarios for the sixth generation of mobile systems.
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Indirect Applications of Additive Manufacturing for Antennas
10 April 2023 Jonathan D. Lundquist, Lauren Linkous, Umar Hasni, and Erdem Topsakal report the fabrication methodology of stereolithography (SLA) printed molds for metal and resin cast antennas. In the first method, a conical horn created using metal cast molds printed from a glass-filled resin utilizes a casting technique allowing for low-cost 3D printing to fabricate metal antennas. The second casting method demonstrates the interchangeability between creating parts via SLA printing with a glass-filled resin and using the same resin cast into a reusable Polydimethylsiloxane (PDMS) mold.
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3-D-Printed Spiral Leaky Wave Antenna With Circular Polarization
05 April 2023 Tomás Lira-Valdés, Eva Rajo-Iglesias, and Francisco Pizarro present the design, manufacturing and measurement of a fully dielectric leaky wave antenna operating at 18 GHz. The antenna is composed of a grounded dielectric substrate with a top dielectric Archimedean spiral corrugation, which allows obtaining a directive pencil-beam in broadside direction with circular polarization depending on the turning sense of the spiral.
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Practical Correlation-Matrix Approaches for Standardized Testing of Wireless Devices in Reverberation Chambers
30 March 2023 Kate A. Remley, Sara Catteau, Ahmed Hussain, Carnot L. Nogueira, Mats Kristoffersen, John Kvarnstrand, Brett Horrocks, Jonas Fridén, Robert D. Horansky, and Dylan F. Williams extend the autocorrelation-based approaches currently used in standards to full correlation-matrix-based approaches in order to identify correlation between both spatially adjacent and non-adjacent samples in reverberation-chamber measurements. They employ a scalar metric that allows users to identify the number of effectively uncorrelated samples in new types of stirring sequences.
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3-D Printed Dually Symmetric Orthomode Transducer and Horn Antenna at X-Band
03 April 2023 Ian Goode, and Carlos E. Saavedra present a dually symmetric orthomode transducer (OMT) and horn antenna for both single port linearly polarized operation and dual port circular polarization use. The feed uses two waveguide splitters and a feed bend to feed a four-port horn antenna that has the two groups of ports orthogonal to each other to produce a symmetric radiation pattern. The feed is printed from 316L stainless steel while the horn is printed from a plastic polymer and metallized using aluminum tape.
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Systematic Design Method for Mutual Coupling Reduction in Closely Spaced Patch Antennas
28 March 2023 Hui Deng, Lei Zhu, and Zhao-An Ouyang present a systematic design approach to reduce the mutual coupling between a pair of closely spaced microstrip patch antennas (MPAs). This method can effectively overcome the main drawback of previous two-path cancellation methods, i.e., lack a systematic design guideline and heavily rely on the time-expensive trial-and-error procedure to mitigate mutual coupling in a best-effort manner. They propose the concept and workflow of the systematic design method, and introduce the circuit-level modeling upon the proposed two coupling routes.
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Angle-Dependent Synthesis Method for Holographic Multi-Feed Antennas
27 March 2023 Thomas Frey, Maximilian Döring, Nico Riese, Christian Waldschmidt, and Tobias Chaloun present a novel synthesis method for holographic multi-feed antennas to combine all sub-holograms into an angle-dependent shared holographic aperture. In order to find the global error minimum between the shared holographic aperture and all ideal sub-holograms, a non-pixel-based genetic optimization is used. For a more accurately implementation of the analytical impedance tensor an eigenvector approach taking all tensor components into account is introduced.
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Additive Manufacturing of Linear Continuous Permittivity Profiles and Their Application to Cylindrical Dielectric Resonator Antennas
16 March 2023 Simon P. Hehenberger, Stefano Caizzone, and Alexander G. Yarovoy consider the utilization of additive manufacturing (AM) to engineer the permittivity profile of dielectric resonator antennas (DRAs). The capabilities of AM are exploited to create continuously swept permittivity profiles and applied to cylindrical DRAs. The spatial variant lattices (SVL) synthesis algorithm is implemented to create the desired permittivity profiles from a single material, and resulting geometries are manufactured using a high-permittivity material in a fused deposition modeling AM process.
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Additively-Manufactured All-Dielectric Microwave Polarization Converters Using Ceramic Stereolithography
15 March 2023 Steve M. Young, Mark Kauf, Jeffrey Kutsch, and Anthony Grbic report a class of all-dielectric, additively-manufactured polarization converters with tailored temporal frequency responses within the Ku and Ka microwave bands (15– 40 GHz). These multi-layer devices consist of cascaded, subwavelength, high-contrast gratings with different fill fractions and orientations, providing control over the effective anisotropic properties of each layer. Three example devices based on alumina/air gratings have been monolithically fabricated using ceramic stereolithography: a broadband reflective half-wave plate, a broadband isotropic polarization rotator, and a dual-band linear-to-circular polarization converter.
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Highly Efficient Calibration of Antenna Arrays by Active Targets in the Near-Field
08 March 2023 Matthias Linder, Benedikt Meinecke, Enes Halici, Dominik Schwarz, and Christian Waldschmidt propose a calibration setup employing active calibration targets (ACT) to reduce the calibration effort, hereby defined as the number of required measurements. The setup allows the storage of a multitude of data points within a single measurement. It is placed in the near-field of the array to relax the requirements on the size of the anechoic chamber. Employing multiple targets makes it challenging to compensate for the near-field effects.