A K-Band Ultra-Wideband Binary Phase Shifter for Phase Modulating Applications in Radar

In this letter, a 180 degrees rat-race coupler-based binary phase shifter is investigated for use in modern radar applications, such as phase-modulated continuous-wave (PMCW) and encoded radars. This phase shifter utilizes a two-section rat-race coupler, along with fast switching p-i-n diodes and microstrip RF chokes, to create a wideband system that includes two active states with a near-180 degrees phase difference between them, equal power usage, and less than 10 dB of insertion loss. The performance of this design is directly compared to a single-section rat-race couplerbased binary phase shifter that employs the same reflective loading structure. For this design, the operating bandwidth is 10.37 GHz, across which the binary state phase error between active states is less than +/- 10 degrees, making it suitable for full-band radar applications.