A Loaded Line 2-Bit Phase Shifter Using RF MEMS DC/Capacitive Switches

This letter presents the fabrication and measurement of a novel loaded line phase shifter design providing four different phase shifts using only two RF MEMS switches. The flexibility of choosing DC or capacitive load depending upon the phase shift required in a single RF MEMS switch makes the phase shifter compact and requires less number of proposed switches. The RF MEMS switch has been designed to provide isolation better than 10 dB in both DC and capacitive states from 16 to 45 GHz. Due to the designed RF MEMS beam switching between DC and capacitive loading, the proposed phase shifter provides a 2-bit phase shift using only two switches. The measured phase shifter has the maximum insertion loss of 0.8 dB with a bandwidth of 8 GHz from 16 to 24 GHz. The return loss is better than 10 dB for all four states. The maximum Root-Mean-Square (RMS) insertion loss error is 0.28 dB, and the phase shift error is 0.98°. The proposed phase shifter is fabricated using the surface micromachining on the sapphire substrate and occupies an area of 3.931 mm2. © 2023, Electromagnetics Academy. All rights reserved.