A Novel S-Band Butler Matrix for Mobile Telecommunication Satellite

A Novel S-Band 8×8 Butler Matrix employing miniaturized micro-strip branch-line directional coupler is proposed and implemented in this paper. The circuit is fabricated with a standard double side PCB process. The total size of the Butler Matrix is 155mm×145mm. The differ of the output phase shift is less than ±3^°. The variety of the IL is less than ±0.2dB. Thus, it is a good candidate for beam-forming networks of microwave multi-beam antennas for satellite. The detailed design process and the measured results are presented.