Novel Multi-way Broadband Differential Phase Shifter With Uniform Reference Line Using Coupled Line Structure

Conventional passive differential phase shifters (DPSs) usually require different reference lines to realize varied differential phase shifts, this results in both complex structure and bulky size for multi-way poly-phase applications. To resolve the problem, a DPS configuration with uniform reference line is proposed. It is constructed using basic coupled lines with simplicity in both design and fabrication procedures. The delay lines of the phase shifter have a similar structure and maintain desired constant phase shift compared with the uniform reference line over a wide bandwidth. To verify the proposed configuration, a four-way DPS which is comprised of 3 delay lines and a reference line, is designed, fabricated and measured. The delay lines provide the corresponding constant phase shifts (45°, 90°, 135° compared to the reference line. Over a bandwidth of 45%, excellent performance is achieved with small insertion loss and phase deviation.