Microstrip antenna array with four port Butler matrix for switched beam base station application

Abstract

In this paper, the design of a microstrip antenna array with four port Butler matrix is presented. The Butler matrix is used as a beamforming network and it produces orthogonal beams that can be steered in different directions. Simulated butler matrix has 10 dB return loss bandwidth of 20%. This matrix feeds four single element microstrip antennas that can be operated from 2.412GHz to 2.484GHz. The circuit is designed by considering a single layer microstrip structure that makes it simpler. The design of wide band microwave devices such as branch-line coupler; cross-coupler and phase-shifters are also incorporated. The switched beam antenna is designed for 2.4GHz band Wi-Fi (Wireless Fidelity) system.