Comparison between three radiation pattern using butler matrix for beamforming network

Abstract

Butler Matrix is a beamforming network (BFN), functioning as a feeding network of antenna array. It provides multiple values of progressive phase different of excitation current to an antenna array. By integrating Butler Matrix with antenna array, multiple beams on radiation pattern could be created. In this work, three different types of antenna array have been integrated with the same Butler Matrix and the radiation patterns of each configuration have been compared. The chosen antenna types in this project are 4 × 1 proximity feed square patch antenna array, 4 × [4 × 2] antenna array and 4 × 1 monopole antenna array. They are chosen as each of them has different radiation pattern characteristic. The obtained results show that four independent beams with different angles are generated by individual array where square patch antenna array has Half Power Beamwidth (HPBW) about 30° for each beams and manage to cover 120° of coverage area, [4 × 2] antenna array has HPBW about 7° and cover 30° while monopole antenna produce two kind of beams, broader and narrower beams. The comparison between the measured and computed radiation pattern of each antenna array are presented.