Millimetre-wave beam-steering array antenna by emphasising on improvement of Butler matrix features

Abstract

To conquer troubles such as disruptive effects in mm-wave frequency, many researches have been challenged. Beam-steering antennas, especially with Butler matrix feed network, are a good suggestion to solve the aforementioned problem. In this study, an innovative design of the Butler matrix fed network is presented to drive patterns of the antenna. Moreover, a broadband Butler matrix feed network is achieved by a 1 × 4 aperture coupled zeroth-order resonance elements which increases beam-width of array pattern to triumph short-range effect. Also using aperture fed, stable broadside pattern is obtained. The offered Butler matrix composes of four 90° couplers which have a combination of edge and patch techniques in the coupler, and two broadband stepped 45° phase shifters. The proposed compactness beam-steering antenna covers an impedance bandwidth from 33.20 to 37.15 GHz and scans solid angle about ∼94° with the peak gain of 12 dBi.