Abstract: In order to overcome the problems of narrow band and poor performance existed in the current design of multi beam switched antenna, this paper studies the butler matrix based design methods of feed network and the fast design technique of the differential phase shifter. The results realized the broadband multi beam synthetic networks with a 23% bandwidth. The bandwidth of microstrip array's unit is increased by using the V shaped slot loaded by rectangular patch and the distortion of double shaped stub to coupled feeding. As a consequence, we obtain a broadband, high gain, and multibeam mobile communication antenna system. The measured results show that this antenna system can generate four beams covering 900 working area seamlessly. The VSWR is less than 1. 5dB and the gain can reach 16dBi.