Waveguide Butler Research Articles

Compact Multibeam Antenna Array Facilitated by Miniaturized Slow Wave Substrate Integrated Waveguide Butler Matrix

Compact Multibeam Antenna Array Facilitated by Miniaturized Slow Wave Substrate Integrated Waveguide Butler Matrix

Design and Fabrication of PTFE Substrate-Integrated Waveguide Butler Matrix for Short Millimeter Waves

We attempt to design and fabricate of a 4×4 Butler matrix for short-millimeter-wave frequencies by using the microfabrication process for a polytetrafluoroethylene (PTFE) substrate-integrated waveguide (SIW) by the synchrotron radiation (SR) direct etching of PTFE and the addition of a metal film by sputter deposition. First, the dimensions of the PTFE SIW using rectangular through-holes for G-band (140-220 GHz) operation are determined, and a cruciform 90 ° hybrid coupler and an intersection circuit are connected by the PTFE SIW to design the Butler matrix. Then, a trial fabrication is performed. Finally, the validity of the design result and the fabrication process is verified by measuring the radiation pattern.

Wideband mm-wave high-gain multibeam antenna array fed by 4 × 4 groove gap waveguide butler matrix with modified crossover

This paper presents a wideband millimeter wave (mm-Wave) high-gain multibeam antenna array fed by Butler Matrix (BM) based on groove gap waveguide (GGW) technology. First, the components of 4 × 4 GGW BM have been designed and analyzed, especially the proposed modified crossover, which greatly improves the performance of BM as feeding network. Then a 2 × 2-element subarray with three layers has been proposed, combined with the 4 × 4 GGW BM to form a 1 × 4 broadside antenna array. Finally, the prototype of high-gain wideband four-beam antenna array has been manufactured and measured. The measured results verify the superior performance of the multibeam antenna array between 26.3-29.7 GHz. The return loss (RL) can reach 15 dB and isolation between ports is also less than 15 dB, and the measured maximum gain of radiation patterns and the maximum radiation efficiency can also reach 19.05 dBi and 86.8%, respectively. The measured results have a good agreement with the simulated results.

A compact size wide‐angle 3 × 3 substrate integrate waveguide Butler matrix for Ku‐band applications

In this paper, an array antenna fed by a novel double layer 3 × 3 Butler matrix for Ku-band application was presented. An antipodal Vivaldi antenna (AVA) with dielectric lens was suggested as radiating elements. AVA has a broadband specification along with directive stable patterns at operational bandwidth. Combinational structure of substrate integrated waveguide topology by modified radiating element (AVAs) results to miniaturized size and acceptable radiation efficiency in whole of Ku-Band. Presented array covers frequency range of 13–17.5 GHz (30%) with average gain of 14.2 dBi. The proposed beam-steering antenna with compact size and good performance is capable to cover an angle range from −39 to 38° in whole operation frequency. This structure with unique configuration and specification can be a good candidate for beam-forming application for wireless devices.

Design of a 4×8 Substrate Integrated Waveguide Butler Matrix with Sidelobe Suppression at 60 GHz

Design of a 4×8 Substrate Integrated Waveguide Butler Matrix with Sidelobe Suppression at 60 GHz

Design and evaluation of a vertically integrated passive two‐dimensional beam switching antenna array at 60 GHz

A millimeter-wave two-dimensional (2D) beam switching planar microstrip patch antenna array excited by a 4 × 4 substrate-integrated waveguide Butler matrix (BM) is presented in this article. The BM architecture is modified to feed the planar array in a vertically integrated multilayer design to minimize parasitic effects due to junction discontinuity and reduce the radio frequency (RF) front-end footprint. This feed architecture enables the designer to control the phased array inputs to achieve a set of beam directions in four quadrants of radiation space at a desired elevation angle. For verification of beam switching via over-the-air measurements at 60 GHz, a bench-top anechoic chamber with proper transmitter and receiver antenna positioners was designed and fabricated using in-house laboratory resources. 2D beam steering was confirmed in the intended four quadrants of radiation space at ϕ0 = 50°, 140°, 220°, and 300° and θ0 = 30° ± 5°, meeting the design specifications with a very good margin. Each switched beam demonstrated between 5 and 6 dBi gain at 60 GHz, which is within 1 dB deviation from the simulated results.

V-Band Wideband Circularly Polarized Endfire Multibeam Antenna With Wide Beam Coverage

A V -band wideband circularly polarized (CP) endfire multibeam antenna array with the wide beam coverage is presented in this letter. First, a wideband compact endfire CP element with the wide axial ratio (AR) beamwidth is proposed. The design procedure and working principle of the element are discussed in detail. Besides, connected holes are used to reduce the mutual coupling and improve the AR performance. After that, a wideband substrate integrated waveguide Butler matrix is designed to feed the antenna array. Finally, the multibeam antenna is fabricated, measured and investigated. The measured results demonstrated that the proposed multibeam antenna provides a wide −10 dB impedance bandwidth of 28.5% (55.5 to 74 GHz) and a wide 3 dB AR bandwidth of 24.6% (57 to 73 GHz). Additionally, a wide beam coverage ranging from 45°–66° is achieved. Good agreement achieves between measured results and simulated ones.

A 20-GHz-Band $64\times64$ Hollow Waveguide Two-Dimensional Butler Matrix

In this paper, a 20-GHz-band 64 x 64 hollow waveguide Butler matrix is proposed. By using two-plane short slot couplers and a modified diagram, a short-axis two dimensional Butler matrix is realized. The design method of the diagram and components is presented. The Butler matrix is composed of two plane hybrids, cross couplers and phase shifters. The designed Butler matrix is fabricated by milling and screwing together nine aluminum plates. The dimensions and weight are 86.40 mm x 74.19 mm x 396.34 mm and 7.0 kg, respectively. Transmission characteristics as a beam switching circuit are characterized by measurements, with a low insertion loss of less than 1.8 dB and an excitation error of 4-dB and 40-deg. standard deviation. Radiation characteristics as a 64-beam antenna are measured, and a wide coverage area of 40% of the hemisphere and high directivity of more than 18.7 dBi were determined by measurements.

Characterization of a 4 × 4 substrate integrated waveguide Butler matrix at 60 GHz for two‐dimensional beam steering

A 4x4 substrate integrated waveguide (SIW) Butler matrix for two-dimensional (2-D) beam steering operating at 60 GHz is developed and experimentally evaluated in this article. The SIW beamforming network is a Butler matrix that is implemented with new designs of its constituent components in order to achieve a compact design. Namely, an SIW phase shifter that uses periodic rectangular slots is introduced for the first time at 60 GHz to replace the more area-consuming meandered SIW. The phase shifter prototype, fabricated and measured as a proof of concept, demonstrates achieving an additional 20.3° of phase shift with using only 3 apertures without increasing the length or meandering the SIW line. The hybrid coupler and crossover sections of the SIW Butler matrix are also optimized to reduce the overall area of Butler matrix by 53.9%. The SIW Butler matrix prototype is fabricated and measured demonstrating achieving the differential output phase values needed to switch the beam of a 2-D array in four quadrants while keeping the insertion loss magnitude imbalance of below 1.47 dB from simulations and 3.34 dB from measurements.

Fabrication of Integrated PTFE-Filled Waveguide Butler Matrix for Short Millimeter-Wave by SR Direct Etching

Fabrication of Integrated PTFE-Filled Waveguide Butler Matrix for Short Millimeter-Wave by SR Direct Etching

SIW Butler Matrix with Modified Hybrid Coupler for Slot Antenna Array

This paper presents a substrate integrated waveguide Butler matrix with a modified hybrid coupler, operating from 28 to 32 GHz. The modified hybrid coupler is realized by using 90° hybrid coupler followed by a -45° compensating phase shifter. Thus, 45°/135° output phase differences can be obtained using this type of coupler. Compared with the equal-length unequal-width phase shifter, the compensating phase shifter exhibits better phase characteristics, with only 3° phase error over 28-32 GHz. Because the phase of compensating phase shifter is not realized by taking the phase introduced by the crossover as a reference, it gives great flexibility to the design of compensating phase shifter. Adopting the modified hybrid coupler, the designed Butler matrix features the output phases with peak to peak error of 13° and wideband performance from 28 to 32 GHz. The slot array fed by the Butler matrix can radiate four slanted beams with acceptable measured gains, in the range of 9.7~12 dBi for port 1 excitation and 8.4~11.1 dBi for port 2 excitation. The radiated beams can reach a wide azimuthal coverage between ±61°.

Ka 대역 광대역 다중 단자 증폭기를 위한 도파관 8×8 버틀러 매트릭스 설계

Herein, we design a wideband waveguide Butler matrix in order to use in a multi-port amplifiers(MPAs) at Ka-band. To achieve the broadband characteristic, we design a binomial 6-slot 3 dB directional coupler which is used to configure the Butler matrix. The measured results of the fabricated Butler matrix have low insertion loss of less than 0.3 dB, good return loss of over 26 dB and high isolation of over 35 dB within the design bandwidth of 3 GHz.

Design of a 60-GHz Substrate Integrated Waveguide Butler Matrix—A Systematic Approach

A 60-GHz substrate integrated waveguide Butler matrix designed based on a systematic approach is fabricated by a standard single-layer print circuit board process, which is more economical for mass production than are the advanced processes such as low-temperature co-fired ceramic, thick-film process, etc. The systematic approach involves design equations, simulations, and measurements. Starting with a set of explicit design equations for the short-slot couplers, one calculates the structure dimensions. The calculated dimensions are then optimized with full-wave simulation to finalize the design of the key components, including the couplers and phase shifters. With the use of a noncoaxial multiport measurement technique, the characteristics of the components are acquired through a probe station and a two-port vector network analyzer. Measurement technique plays a critical role in the systematic design approach. By measuring at the intrinsic ports or the wave ports defined in the full-wave simulations, the components are unambiguously verified and then integrated to complete the design of the Butler matrix. The resulting Butler matrix is also verified by the measured eight-port <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> -matrix, which is shown in good agreement with the simulated one. As the measured results of the Butler matrix show, for the operating bandwidth from 58 to 62 GHz, the reflections and isolations are lower than -13.5 dB and the insertion losses are below 2.5 dB. Much like the measured results of the components, the measured eight-port <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> -matrix not only verifies the design of the Butler matrix, but also will facilitate the follow-on design of a switched-beam antenna array.

Compact Designs of Waveguide Butler Matrices

Architectures of waveguide Butler matrices, for linear and planar arrays, utilizing both short-slot and top-wall hybrids, yield short path from input to output, minimize losses, save flanges, and reduces network size and weight. Novel three-dimensional (3-D) Butler matrix beamformer for volumetric multibeam from planar array is also presented.