Experimental Investigation of a Photogenerated Silicon Plasma Monopole Antenna

This work investigates the photoconductive effect in high-resistivity silicon (HRS) as the radiating element of a plasma monopole antenna. A silicon chiplet forming the monopole is mounted on top of an antenna feed network patterned on a printed circuit board (PCB) substrate. By exciting the silicon chiplet with a light source supplied by optical fibers, the monopole can be changed from a dielectric to a conductor, thus making the antenna indistinguishable from typical substrates in the OFF-state and radiating in its ON-state. The experimental results show a peak broadside realized gain of −2.6 dBi at 16.9 GHz and an ON/OFF ratio greater than 17.8 dB from 14.2 to 20 GHz. The silicon plasma antenna is also shown to radiate between 43% and 62% of the broadside power in comparison to a fully copper monopole antenna with equivalent dimensions. The proposed photogenerated silicon plasma monopole antenna demonstrates significant potential as an antenna element for integration within a plasma antenna array system.