Broadband Fixed Phase Shifter for C-band Applications

The design of a broadband fixed phase shifter for C-band applications is presented. The proposed device is composed of two parts: a quadrature 3 dB directional coupler, which is based on the edge-coupled microstrip lines with a slotted ground plane, and the Wilkinson combiner. The phase shifter presented in this paper shows a 45degplusmn5deg fixed phase shift across the band 4 GHz to 8 GHz with less than 1 dB insertion loss and better than 12 dB return loss at the centre of the C-band. The designed device also shows a flat group delay, which enables its use in a narrow pulse transmission/reception and in the high data rate systems. The designed phase shifter has a compact size with dimensions of 30 mmtimes35 mm.