Wideband Sub-Thz Evanescent-Mode Waveguide Switch Using Reconfigurable Photogenerated Solid-State Plasma Elements

The first measurement of a wideband sub-THz waveguide switch using silicon posts inside a micromachined evanescent-mode waveguide channel is presented in this paper. The reconfiguration is achieved by changing the dielectric and conductive properties of the shunt silicon posts through photogenerated solid-state plasma. By increasing the number of silicon posts within the evanescent-mode region of the waveguide switch, exceptionally high OFF-state isolation greater than 44 dB, ON-state insertion loss less than 0.4 dB, and return loss greater than 10 dB across the entire G-band from 140 to 220 GHz is achieved. Moreover, the OFF-state attenuation of the switch can be precisely controlled by varying the applied optical power demonstrating a variable attenuator. These results demonstrate the exciting potential of this high-performance switch technology for sub-THz applications in a low cost, silicon-based semiconductor platform.