A W-Band SPDT Photoconductive Evanescent-Mode Waveguide Switch

Abstract

This letter presents the design, fabrication, and measurement of a silicon micromachined photoconductive evanescent (EVA)-mode waveguide switch operating in a single-pole double-throw (SPDT) configuration. Two EVA-mode waveguides loaded with silicon posts are placed in a Y configuration with a common feeding waveguide. In the absence of photoexcitation, the dielectric posts and EVA channel exhibit a bandpass filter response that allows low-loss propagation of signals on the order of 2.0 dB at 96.7 GHz. When photoexcited, the low conductive posts and EVA channel yield a very high isolation of 36.5 dB up to 102.4 GHz within <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$W$ </tex-math></inline-formula> -band. The proposed design shows promise for 5G and 6G communication backhaul devices.