Liquid Metal-Based Linear Self-Complementary Phase Shifter for Phased Array Antenna

This paper proposes a liquid metal (LM)-based linear tunable phase shifter. A via-pad-slot (VPS) structure is realized by using a slot to isolate a via from the ground. The shunt inductance and capacitance are loaded on the HMSIW when the VPS structure is inserted in the HMSIW. While the capacitance will be removed when the square slot is filled by LM. The shunt inductance and capacitance have complementary phase effect which causes a small phase deviation with frequency. According to the proposed VPS structure, a X-band linear tunable HMSIW phase shifter range is 0-100° when the slots are sequentially filled by LM. The measured insertion loss (IL) is 0.85 dB, the phase shift ranges from 0 to 100° within 9.5-13 GHz (31.11%), and the average phase resolution is about 1.79°. The phase shifter offers benefits such as low insertion loss, high resolution, linear phase adjustment, and negligible phase deviation, which is attractive to passive phased array antenna design