A 90° Self-Compensating Slab Air-Filled Substrate Integrated Waveguide Phase Shifter

This paper presents a 90° self-compensating phase shifter based on a slab air-filled substrate integrated waveguide platform in Ka-band. A shorter phase shifter is obtained due to its operation mechanism. The measurement shows a relative phase shift of 88 ± 7.8°, or around 8.9% for phase error, and an amplitude imbalance of 0.06 ± 0.14 dB over Ka-band. A theoretical study is presented together with simulation to understand the operation principle of this phase shifter. Simulation and measurement results are compared and discussed.