Design of an X-band Photoconductive Metasurface with Variable Amplitude Control

An optically controlled metasurface design is presented. The unit cell of the metasurface consists of a die of high-resistive silicon mounted over a gap between two metallic patches. The switching performance of the silicon die is first investigated by transmission line measurements. Then a reflective metasurface prototype is fabricated and a waveguide experimental setup is used to verify the photoconductive ability of the metasurface when pumped by a laser source. The results show a tunable reflectivity from 2.0 dB to 14.0 dB in X-band. The proposed photoconductive metasurface is prominent with no metallic bias lines and hence can be used for reconfigurable electromagnetic interference shielding applications.