Waveguide Slot Array Antenna Research Articles

Correction: A novel design of non-bending narrow wall slotted waveguide array antenna for X-band wireless network applications

Correction: A novel design of non-bending narrow wall slotted waveguide array antenna for X-band wireless network applications

Effective bandwidth improvement of Travelling-Wave waveguide array antennas using double Parallel-Slot radiating elements

The effective bandwidth of a travelling-wave slotted waveguide array antenna is improved by using a proposed broadband single radiating element based on a pair of longitudinal slots CNC-machined in the broad wall of the waveguide. The TE10 mode excites two resonances generated by each slot, providing an effective bandwidth improvement. As a proof of concept, an array antenna formed by 16 double longitudinal parallel-slot elements is designed. A prototype has been manufactured in printed technology in order to experimentally validate the antenna performance. Measurements show high stability of efficiency, maximum gain and radiation patterns in a broadband higher than 20% in the K-band.

A novel design of non-bending narrow wall slotted waveguide array antenna for X-band wireless network applications

A novel design of non-bending narrow wall slotted waveguide array antenna for X-band wireless network applications

A Circularly Polarized Non-Resonant Slotted Waveguide Antenna Array for Wide-Angle Scanning.

A compact circularly polarized non-resonant slotted waveguide antenna array is proposed with the aim of achieving wide-angle scanning, circular polarization, and low side-lobe levels. The designed antenna demonstrates a scanning range of +11° to +13° in the frequency domain and a beam scanning range of -45° to +45° in the phase domain. This design exhibits significant advantages for low-cost two-dimensional electronic scanning circularly polarized arrays. It employs a compact element that reduces the aperture area by 50% compared to traditional circular polarization cavities. Additionally, the staggered array method is employed to achieve an element spacing of 0.57λ within the azimuth plane. Isolation gaps were introduced into the array to enhance the circular polarization performance of non-resonant arrays. The Taylor synthesis method was employed to reduce the side-lobe levels. A prototype was designed, fabricated, and measured. The results indicate superior radiation efficiency, favorable VSWR levels, and an axis ratio maintenance below 3 dB across the scanning range. The proposed antenna and methodology effectively broaden the beam scanning angle of circularly polarized slotted waveguide array antennas.

In-band dual-polarization RCS reduction of waveguide slot array antenna integrated with AMC and PEC chessboard structure

An in-band low radar cross section (RCS) waveguide slot array antenna (WSAA) is proposed by using a chessboard structure composed of artificial magnetic conductor (AMC) and perfect electric conductor (PEC), which serves as the antenna radiator. The method for RCS reduction is the reflection energy cancellation. Standing wave array is used to achieve higher energy efficiency and more compact antenna structure. Experimental results show that the in-band monostatic RCS is sufficiently reduced with the chessboard structure application for both co- and cross-polarized incident waves, where 10-dB RCS compression is realized among the frequency range of 9.7–9.91 GHz for co-polarization and 9.5–9.85 GHz for cross-polarization with maximum RCS reductions of −13.3 dB and −11.9 dB, respectively. Meanwhile, the designed WSAA maintains the high gain characteristics of the original WSAA. The paper provides a simple, practical and effective strategy for stable RCS compression in the operation band of waveguide antenna array, which has potential applications in stealth platforms.

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.

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.

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.

A Low RCS Waveguide Slot Antenna array with Metamaterial Absorber

We propose a novel design to reduce the radar cross section (RCS) of ridged waveguide slot antenna array with metamaterial absorber (MMA). The MMA consists of metallic pattern and solid metal on sides of a dielectric slab, of which the absorbing characteristics and mechanism are analyzed. The PEC ground plane of a ridged waveguide slot antenna array is covered by MMA. Both the simulated and measured results show that compared with the waveguide slot antenna array with a PEC ground plane, the RCS of proposed antenna array are reduced dramatically without degradation of antenna performance. Combining with the bandpass frequency selective surfaces technology, the guideline illustrated by the proposed examples will serve as a good candidate for the future design of low RCS antenna.

A Compact Slotted Waveguide Array Antenna With a Cubic Post Radiator for Aerial Vehicle Applications

A Compact Slotted Waveguide Array Antenna With a Cubic Post Radiator for Aerial Vehicle Applications

Ultra-low SLL slotted waveguide antenna array using Chebyshev aperture distribution function for MM-wave tracking radar applications

A non-uniform aperture distribution slotted waveguide antenna is presented. The slotted waveguide antenna array is chosen for its ease for aperture distribution control and the flexibility of gain adjustment. Multiple aperture distribution functions, including uniform, binominal, Chebyshev, and Blackman, have been extensively investigated to achieve the best possible side lobe suppression. These distribution functions have been converted to slot displacement from the center line of the antenna. Number of slots in the proposed array is chosen to be eight to satisfy the required gain for mm-wave radar tracking application. The proposed antenna is simulated and optimized using the full wave simulator package (CSTMWS). Rounded edge slots are adapted instead of the sharp ones, as they are more applicable for the CNC fabrication process. An eight-slot waveguide antenna is fabricated and gold-plated, considering the Chebyshev distribution approach. The proposed design achieves very stable radiation characteristics and performance over the operating bandwidth, which extends from 33.6 GHz up to 35.9 GHz. At 35 GHz, the total realized gain of the overall antenna is found to be 13.4 dBi, with an overall radiation efficiency of 95.21 %. An obvious low SLL of −30 dB is obtained at the frequency of 35 GHz. The low side lobe level parameter is very crucial for radar applications as it enhances the overall target SNR and reduces false target observations. The pre-stated antenna characteristics make it a good candidate for mm-wave radar applications and point-to-point communications (P2P).

A Substrate Integrated Waveguide Slotted Antenna

Introduction. Slotted waveguide antenna arrays are widely used across centimeter- and millimeter-wavelength ranges due to numerous advantages, including their good directional properties, compact dimensions, flat shape, convenience of power supply, and high efficiency. At the same time, the current trend toward miniaturization of electronic devices and their integration requires new solutions, such as the development of devices based on wave-guides integrated into the substrate (Substrate Integrated Waveguide – SIW).Aim. To simulate a SIW-based slotted antenna with characteristics similar to those of a conventional antenna array based on a hollow metal waveguide.Materials and methods. The Ansys HFSS software was used to simulate the structure under study and to carry out electro-magnetic modeling and analysis of its directional properties. The energy method was used to determine the coordinates of longitudinal slots on the wide wall of the SIW waveguide. Macros were developed in the Visual Basic Scripting Edition language to automate routine operations for creating and deleting objects of the same type when constructing a model. The Arlon AD300C microwave material was used to manufacture a printed version of the SIW waveguide.Results. The process of developing a SIW slotted antenna was carried out in the following stages: construction of a reference model based on a hollow metal waveguide followed by creating a transition model based on a waveguide completely filled with a dielectric and the final SIW-based model. At each stage, the radiation pattern was monitored to obtain the directional properties of the SIW slotted antenna with characteristics identical to those of an antenna based on the reference hollow metal waveguide.Conclusion. A SIW slotted antenna with the required characteristics was simulated and tested in the Ansys HFSS environment. Such an antenna employs one of the main advantages of the SIW technology, i.e., the possibility of integrating all components on a single substrate, including antenna arrays, passive components, and active elements. This approach provides the basis for reducing the size of microwave devices and their miniaturization.

Compact Additively Manufactured Conformal Slotted Waveguide Antenna Array

In this work we present the design and fabrication in metallic 3D-printing of a compact conformal slotted waveguide antenna array operating in the Ku-band. The application objective, although not limited only to this, is the optimisation of an antenna element which by stacking will be able to form a quasi-cylindrical sector. A beamforming network will be used for beam-steering in the elevation plane as coverage in the azimuthal plane is guaranteed by the conformal geometry. The compact design of the antenna element is therefore of great significance. For this reason, a direct feeding scheme by a coaxial connector is adopted. The antenna has been optimized following multiple parametric analyses of its geometrical parameters for the enhancement of the bandwidth, return losses and realized gain. The antenna was fabricated with Selective Laser Melting in aluminium and the experimental results agree well with the numerically calculated ones. The proposed CSWAA exhibits a reflection coefficient below -10 dB, realized gain above 14 dBi, as well as good cross-polarization and side-lobe level over a relative bandwidth of 8%.

Low-Profile High-Efficiency Transmitarray Antenna for Beamforming Applications

A low-profile high-efficiency transmitarray antenna (TA) for beamforming applications is proposed and investigated in this paper. The partial H-plane waveguide slot array antenna is employed as the compact low-profile feeding structure of the beamforming TA. The designed TA can achieve a high taper efficiency due to the multi-array sources and the compactness of the partial H-plane waveguide. Moreover, the proposed TA can inherently have a high spillover efficiency because the frequency selective surface (FSS) for beamforming is located just above the radiating slot. The FSS with a transmission phase variation of 2π is designed by a square patch array and used to manipulate the wave-front of the transmitted electromagnetic wave instead of a complicated feed network and phase shifters. To verify its beamforming characteristic, three types of FSSs to operate a forming angle of −40°, −20°, 0°, +20°, and +40° are designed at 12 GHz. The distance between the FSS and the slot array antenna is 0.1λ0, and the aperture efficiency is measured to be about 69%. The measured results, such as the reflection coefficient and the far-field radiation pattern, are in good agreement with the simulated results. From the measured results, the proposed TA is confirmed to have good beamforming characteristics and high aperture efficiency.

Slotted-Waveguide Antenna Array Development by Means of Complementarity оf CST Microwave Studio and Compass 3D Programs

The main steps of the methodology for complex slotted-waveguide antenna arrays development using the complementary application of the COMPASS 3D design program and electromagnetic modeling CST Microwave Studio are considered. The presentation of the technique steps is carried out on the example of a structurally complex slotted-waveguide antenna array of the Ka-band with dimensions (117 mm ´ 30 mm) and two-dimensional array of 64 (2 ´ 8 ´ 4) slotted emitters. To facilitate the synthesis of the design parameters of such grids, it is proposed to use a three-stage process: 1) design of slotted antenna emitting modules with adjustment to a given operation frequency range; 2) development of harmonized multichannel power divider for them; 3) combining the antenna modules and the branched power divider into an effective antenna array with additional adjustment of their coordination parameters. According to this sequence, in the illustrated example, on the first step, the antenna emitter module with four slits is designed in the CST Microwave Studio program. Afterwards, on the second stage, a complex multi-channel waveguide power divider was designed. It is first drawn in COMPASS 3D and then imported and analysed in CST Microwave Studio. On the final third stage, the entire slotted-waveguide antenna array was assembled and simulated in CST Microwave Studio. At the same time, the obtained radiation pattern of the antenna array, the functions of electromagnetic field distribution in the waveguide path and other electromagnetic characteristics corresponded to the required ones. Equally, there was a slight shift in the standing wave ratio (SWR) of the operating frequency matching, as well as some deterioration in the SWR. This is explained by the fact that the links between the models of antenna emitters and the waveguide power distributor were carried out 'in ideal ports'. Meanwhile, the real values of the input resistances in these planes of the assembled structure are somewhat different from the ideal ones. Therefore, to complete the process of structural synthesis of the antenna-slot array, two approaches should be used: 1) it is better to complete design parameter optimization according to the criterion of improving the harmonization, if required to shift the operating frequency, 2) to reduce the SWR value, it is better to improve the coordination of the antenna array at its input by adjusting the matching device.

Design of Dual-Stopband Rectangular Waveguide Slot Array Antennas

A dual-stopband rectangular waveguide slot array antenna is presented in this paper. Firstly, a rectangular filtering waveguide with dual stopbands is realized by periodically loading a row of T-type resonators and a row of Π-type resonators on the bottom broad wall of the rectangular waveguide, and its dual-stopband characteristic is verified by analyzing the equivalent circuit and dispersion curve. Secondly, a dual-stopband rectangular waveguide slot array antenna is obtained by etching radiation slots on the top broad wall of the filtering waveguide. To verify the proposed concept, a dual-stopband rectangular waveguide four-slot array antenna is designed, fabricated, and measured. The measured results are in good agreement with the simulation ones. The results show that, compared with the conventional waveguide slot antenna, the proposed waveguide slot antenna has almost the same radiation performance in the –10 dB impedance bandwidth of 5.51–5.95 GHz, and achieves additional suppressions of greater than 24.5 dB in 6.6–7.1 GHz and 34.6 dB in 8.4–9.3 GHz, respectively, without occupying extra space.

A Massively Parallel Preconditioned FEM–BEM Method for Accurate Analysis of Complex Electromagnetic Field Problems

In this letter, a parallel preconditioned FEM-BEM method is presented for the solution of challenging electromagnetic (EM) field problems, especially for calculating the radiation characteristics of electrically large radome antenna systems. A preconditioner that combining the absorbing boundary condition (ABC) with the improved additive schwarz method is first proposed for the FEM-BEM system to improve the convergence. Then, an efficient parallel framework based on message passing interface (MPI) and open multi-processing (OpenMP) is designed to achieve massively distributed parallelization of the method. Numerical results demonstrate the benefits of the proposed preconditioner over traditional additive schwarz method, as well as the accuracy and parallel scalability of the implemented method. Finally, a complex EM system consisting of a waveguide slot antenna array and a dielectric radome with more than 127 medium wavelengths is simulated to verify the capability and effectiveness of the presented method.

A dual‐band dual‐polarized shared‐aperture SIW slot antenna array with beam scanning

AbstractThis letter proposes a low‐profile dual‐band dual‐polarized (DBDP) substrate‐integrated waveguide (SIW) slot antenna array with beam scanning. By stacking the SIW transverse slot array (TSA) above the longitudinal slot array (LSA) in one aperture, two orthogonal polarizations are generated at two bands. To avoid the radiation slots of the LSA and the TSA from overlapping, the LSA is developed based on the proposed LSA unit whose collinear‐slot arrangement is realized by introducing metallized vias. Two planar parabolic reflectors based linear source generators (LSGs) are integrated to feed the shared‐aperture radiation array. By moving two independent SIW horns, the proposed antenna can obtain the steering angles of ±34° and ±27° at the central frequencies of 11.2 and 13 GHz, respectively. Two beams with orthogonal polarizations scan in the same plane. The simulated results have been validated by the experimental ones. The proposed antenna has low profile and is a potential candidate for satellite and wireless communications.