Analog type millimeter wave phase shifters based on mems tunable high-impedance surface in rectangular metal waveguide

Possibility of compact low loss analog type millimeter wave phase shifter was demonstrated. The phase shifter is controlled by a MEMS tunable high-impedance surface placed, e.g., as a backshort or as sidewall inclusions of a rectangular metal waveguide. Reflection type phase shifter can provide differential analog phase shift from 0 deg. to up to 240 deg. Reliable and tunable MEMS based high-impedance surface has been demonstrated for the first time. The insertion loss of the fabricated MEMS tunable high-impedance surface varies from 0.7 dB to a maximum of 3.5 dB (at a resonance frequency), which is a dramatic improvement over our previous non-tunable prototype.