90° and 180° phase shifter using an arbitrary phase-difference coupled-line structure

Abstract

In this paper, an arbitrary phase-difference structure using short-circuit stubs and coupled-line with weak coupling is presented. Compared with conventional coupled-line phase shifters, the proposed coupled-line configuration covers a wide phase range over a broad band. The simulation exhibits a phase range from 15° to 180°. To verified the configuration, 90° and 180° phase shifters are fabricated and measured. According to the measurement results, both 90° and 180° phase shifters achieve bandwidths over 60% with in-band performance of return loss greater than 10 dB, insertion loss less than 1 dB, and phase deviation less than ±5°.