90 Degrees And 180 Degrees Phase Shifter Using An Arbitrary Phase-Difference Coupled-Line Structure

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 degrees to 180 degrees. To verified the configuration, 90 degrees and 180 degrees phase shifters are fabricated and measured. According to the measurement results, both 90 degrees and 180 degrees 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 degrees.