A W-Band Single-Pole Double-Throw Photoconductive Evanescent-Mode Waveguide Switch

The design, fabrication, and measurement of a novel silicon micromachined photoconductive evanescent-mode waveguide single-pole double-throw switch is presented in this paper. Two evanescent-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 evanescent channel form a Chebyshev bandpass response that allows low-loss propagation of signals on the order of 2.0 dB at 96.7 GHz. When photoexcited, the now conductive posts and evanescent channel yields very high isolation on the order of 36.5 dB up to 102.4 GHz. The proposed design shows promise for 5G and 6G communication backhaul devices.