Slot Array Research Articles

Design of the Monopulse Feeding Network for a Slotted Waveguide Array on an Annular Disk

Design of a monopulse feeding network including a compact power distribution network and a monopulse comparator for a dual polarization slotted waveguide array fabricated on an annular disk is presented in this paper. As the slotted waveguide array is arranged on an annular disk, the feeding network is more complicated than that of a regular array such as a rectangular array. The design details of some key waveguide components, such as the compact assembly of H-plane T-junctions and E-plane elbows used to connect power distribution networks and radiation waveguides, are provided. Quasiplanar magic tees are designed and used to construct the compact sum and difference comparator. The antenna system contains two comparators, which are used to generate sum and difference beams for horizontal polarization and vertical polarization, respectively. Finally, the monopulse slotted waveguide array antenna is divided into two modules, a comparator module and an antenna module (including power distribution network), and fabricated with the layered processing and bonding process. The comparator module is measured using a network analyzer to verify its amplitude-frequency characteristics and phase-frequency characteristics. Screwing the comparator module and the antenna module together, a monopulse slotted waveguide array antenna is obtained, and the sum beam and difference beam characteristics of the antenna are measured in a microwave chamber and presented.

Planar slotted waveguide antenna array for monopulse radar

In monopulse radar, along with mirror and lens antennas, slotted waveguide antenna arrays (SWA) are often used, especially in those cases when it is required to have a flat non-protruding shape and compact dimensions. The design and manufacturing of such antennas have specialties associated with the use of non-standard feeding systems of radiating waveguides, which are considered in this paper as the example of creation of a flat SWA intended for use in a monopulse search and tracking radar. The aim of the article is calculating and modeling a slotted waveguide antenna array based on a hollow metal waveguide with a given level of side lobes and main lobe width of the radiation pattern. The developed SWA contains a radiating and feeding part. The radiating part, with 24 linear resonant waveguide-slot antennas with longitudinal slots on the wide wall of the waveguide, is divided into two subarrays to realize the monopulse mode. Each subarray is fed from the feeding waveguide through slanted slots cut in the wide wall of the waveguide. The antenna design calculation has been carried out in the MathCad, and the modeling has been performed in CAD Ansys HFSS. The energy method has been used to calculate the coordinates of the longitudinal slots on the wide wall of the radiating waveguide as well as the inclined slots on the wide wall of the feeding one. The calculated radiation patterns of the developed antenna array in the E- and H-planes in sum and difference modes have been shown. The paper outlines the methodology for designing a monopulse antenna system using a SWA. The system forms a beam directed perpendicular to the antenna plane. During the design process, the slotted waveguide antenna array based on a hollow waveguide has been modeled and researched to obtain the required characteristics specified in the technical requirements. The proposed approach can be applied to practical antenna design for monopulse radars.

Differentially-Fed Slot Array Antenna Backed With High-Order Resonating Cavity Loading Slow-Wave Top–Bottom Double Pins

Differentially-Fed Slot Array Antenna Backed With High-Order Resonating Cavity Loading Slow-Wave Top–Bottom Double Pins

Efficiency enhancement of a circularly polarised slotted waveguide antenna array for Sub-THz applications

Efficiency enhancement of a circularly polarised slotted waveguide antenna array for Sub-THz applications

Generation of OAM beams with quasi omnidirectional pattern using simple slotted waveguide array

Theory and design aspects of the Slotted Waveguide Antenna (SWA) array for the simultaneous generation of Orbital Angular Momentum (OAM) modes are proposed in this paper. The proposed method is a novel approach to OAM generation that uses a simple feeding scheme and has better performance, especially in terms of mode purity. Due to its all-metallic structure, the high-power OAM beams with first-order modes (+1&-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ +1 \\, \\& \\,-1$$\\end{document}) can be generated simultaneously along the propagation axis but in opposite directions, which improves the coverage and makes the proposed SWA be used in applications like radar target detection by mounting it on a mechanically rotating platform. The proposed theory is verified by the electromagnetic (EM) simulations, followed by the experimental verification done on the laboratory prototype. The near-field characteristics of the proposed antenna confirm the generation of first-order OAM beams with high mode purity. The far-field characteristics show the high gain and quasi-omnidirectional radiation pattern. Transmission of high-power OAM beams with good far-field characteristics makes the proposed antenna mitigate the issues of long-range OAM communication to a certain extent. However, the proposed antenna can be served well in strategic applications where the mostly high-power microwave is involved.

A 220 GHz High-Gain Low-Cost Slot Array Antenna With Integrated Fabry–Perot Cavity

A 220 GHz High-Gain Low-Cost Slot Array Antenna With Integrated Fabry–Perot Cavity

A Wideband High-Gain Sawtooth Slot Array Antenna with Frequency-Scanning at Lower Frequency and Fixed-Beam at Higher Frequency

A Wideband High-Gain Sawtooth Slot Array Antenna with Frequency-Scanning at Lower Frequency and Fixed-Beam at Higher Frequency

Research into the Impact of Phase Shifter Failures on the Characteristics of Slotted Waveguide Array Antenna

Introduction. Currently, the impact of phase shifter (PS) failures on the characteristics of phased antenna arrays, slotted waveguide array antenna (SWAA) in particular, represents a significant problem. A review of publications shows that insufficient attention has been paid to PS failures.Aim. To investigate the characteristics of a SWAA in the event of PS failures, when their phase takes a value equal to zero instead of the required value.Materials and methods. The methods of statistical modeling methods were used to study the impact of failures on SWA characteristics. Calculations were carried using the Mathcad 15 software package.Results. An algorithm for statistical modeling of the impact of PS failures on SWAA characteristics is proposed. A relationship that connects the radiation pattern with the volume of the statistical sample and the number of failed PSs is given. The malfunctions of emitters from 5 to 35 out of 50 elements were studied. Changes in the following characteristics were obtained: standard deviation – from 0.064 to 0.18, radiation pattern width – from 8 to 18 %, the level of side lobes – from 13 to 59 %, radiation power – from 0.9 to 0.3.Conclusion. The results obtained can be used in radio-electronic systems with antenna arrays at the stage of their development. Future work will address PS failures with phases being established randomly and with random values, as well as the case of PS failures where power does not pass into the emitter. Another important direction concerns compensation of distortions resulting from failures of antenna elements.

Ultra-Compact 60-GHz Near-Field Focusing Configuration Using SIW Slot Array Loaded by Transmission Coding Metasurface Lens

Ultra-Compact 60-GHz Near-Field Focusing Configuration Using SIW Slot Array Loaded by Transmission Coding Metasurface Lens

A segmented periodic slot array leaky‐wave antenna for beamforming applications

AbstractA segmented periodic slot array leaky‐wave antenna (LWA) is proposed for beamforming applications. The LWA consists of segments, each with a unique propagation constant achieved through varying periodicity and slot size. By using segments with different propagation constants, the proposed LWA can achieve beamforming such as flat‐top beams and side‐lobe level (SLL) reduction. The LWA is based on a substrate‐integrated waveguide with periodic double transverse slots in the broad wall of the waveguide. The double slots allow for reflection‐canceling to suppress the broadside stopband and hence can achieve beamforming capabilities in the backward, broadside, and forward directions. Full‐wave simulations are used to demonstrate the proposed concept for flat‐top beamforming in the mm‐wave band at 30 GHz. Experimental demonstration is conducted using two prototypes for flat‐top beams and SLL reduction, with good agreement with full‐wave simulations.

Bandwidth Limits of Connected Slot Arrays

Bandwidth Limits of Connected Slot Arrays

A low radar cross section antenna array based on a liquid metal metasurface

AbstractA low RCS (radar cross section) slot array antenna based on a liquid metal metasurface is proposed. The metasurface consists of 6 × 6 nested ring‐shaped element. The inner ring with a checkerboard distribution can realise 180° ± 37° phase difference, which can effectively reduce the scattering performances for the slot array. The outer and inner ring together can excite more energy from the slot array, thus resulting in increased radiation gains. Therefore, by changing the layout of liquid metal on the metasurface, scattering and radiation enhancement modes can be switched. The measured results show that in the scattering mode, the RCS can be reduced from 8.1 to 17 GHz. While in the radiation enhancement mode, the proposed array with the metasurface can achieve a −10‐dB impedance bandwidth of 9.4–11.2 GHz (17.4%) with a maximum gain of 8.12 dBi. Compared with the slot array without the metasurface, the realised gain is enhanced by 1.2 dBi from 6.9 dBi. The measured results correspond well with the simulated ones.

Enhancing long-range radar (LRR) automotive applications: Utilizing metasurface structures to improve the performance of K-band Longitudinal Slot Array Antennas

In this paper, we introduce a groundbreaking modification to a K-band substrate integrated waveguide (SIW) Longitudinal Slot Array Antenna for Vehicle-to-Everything (V2X) applications, particularly long-range radar (LRR) in the automotive industry. Our approach harnesses an elliptic metasurface capable of distinguishing between TE and TM modes in relation to radiation direction. By utilizing metasurfaces, we effectively address the issue of mutual coupling between antenna elements, which often results in subpar antenna performance. This modification focuses on improving various antenna characteristics, including frequency bandwidth (expanded by approximately four times), sidelobe level (reduced by 4 dB), aperture efficiency (increased to about 44%), and cross-polarization (reduced by an average of 10 dB). In essence, the results demonstrate that the increased number of longitudinal elements can be effectively enhanced by utilizing the metasurface structure, while maintaining an acceptable level of efficiency. As an illustrative case, we design a 1 × 32-element Longitudinal Slot Array Antenna using the Elliott method operating at 24.3 GHz, with the antenna size measuring 12.5 × 154 mm2. Experimental measurements validate our design, showcasing a 10 dB return loss bandwidth of 24.05–24.45 GHz, a maximum gain of 14.45 dBi, a sidelobe level of 24.5 dB, cross-polarization exceeding 30 dB, and an impressive aperture efficiency of 65%.

Effective Design of an Array of Coupling Slots with a Reflection-canceling Wall for a Parallel-plate Slot Array Antenna

Effective Design of an Array of Coupling Slots with a Reflection-canceling Wall for a Parallel-plate Slot Array Antenna

A V-Band 45° Linearly Polarized Gap Waveguide-Based Corporate-feed Slot Array Antenna with High Overall Performance and Robustness

A V-Band 45° Linearly Polarized Gap Waveguide-Based Corporate-feed Slot Array Antenna with High Overall Performance and Robustness

High-Gain Tapered Long Slot Array for Satcom Applications in PCB Technology With Folded Corporate Feed Network

High-Gain Tapered Long Slot Array for Satcom Applications in PCB Technology With Folded Corporate Feed Network

A compact high‐gain slot antenna array with a bidirectional broadside radiation pattern

AbstractA novel bidirectional broadside slot antenna array is proposed in this letter. The outstanding merits of this antenna array lie in the minimum width and the highest gain‐to‐area ratio (G/A) compared to previous works. The ingenious combination of the radiation mode and the transmission mode of slots is adopted, eliminating the design of the feed network. Thus, a simple and compact configuration is obtained. Moreover, two metal plates are added vertically at the sides of the slot array, with a more homogeneous radiation aperture and a higher G/A. With the 3D structure, a compact volume of the antenna array is ensured. For performance evaluation, our proof‐of‐concept design is fabricated with a cuboid dimension of 1.94λ0 × 0.12λ0 × 0.12λ0, where λ0 denotes the wavelength in free space at the centre frequency. An impedance bandwidth of 2.38 to 2.49 GHz is achieved, with a maximum gain of 9.7 dBi and a higher G/A of 39.5. The advantages including compact size and high G/A are paving the path for the potential application of communications in long and narrow spaces.

AI-Based Investigation and Mitigation of Rain Effect on Channel Performance With Aid of a Novel 3D Slot Array Antenna Design for High Throughput Satellite System

AI-Based Investigation and Mitigation of Rain Effect on Channel Performance With Aid of a Novel 3D Slot Array Antenna Design for High Throughput Satellite System

Wideband RCS Reduction for Circular-polarized Slot Array Antennas Based on Composite Metasurface

Wideband RCS Reduction for Circular-polarized Slot Array Antennas Based on Composite Metasurface

Connected Slot Array With Interchangeable ADL Radome for Sub-8 GHz 5G Applications

Connected Slot Array With Interchangeable ADL Radome for Sub-8 GHz 5G Applications