Two dimensional switched beam antenna based on cascaded butler matrix beamforming network

Abstract

This paper presents a low cost, two dimensional (2-D) millimetre wave switched-beam array antenna attained by feeding a planar array antenna with a cascaded 4 x 4 Butler matrix (BM) beam forming network (BFN). To minimise the surface current, ensure low cost and ease fabrication, a single layer has been implemented. The prototype is fabricated and measured results presented. According to the results, the maximum beam scanning of from -41ᵒ to +42ᵒ, and a maximum antenna gain of 13.8 dBi are obtained in the x-z plane. While the maximum beam scanning of from -43ᵒ to +41ᵒ and the maximum antenna gain of 13.7 dBi are realized in the y-z plane. With a single pole multiple throw switches, switching the various matrix terminals on the BM in the horizontal plane gives the beams in the x-z plane, while switching the BM in the vertical plane gives the beams in the y-z plane. All experimental and numerical results are in good agreement which can be practically used for fifth generation (5G) wireless systems. Keywords: Cascaded Butler matrix, Beamforming Network, switched-beam antenna, 5G