M. A. Collett , C. D. Gamlath, and M. J. Cryan, "An Optically Tunable Cavity-Backed Slot Antenna", IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 2017

Abstract—There is a growing pressure 1 on antenna designers
2 to provide ever increasing operating bandwidth, efficiency, and
3 flexibility. Emerging communications standards are requiring
4 operation over wide frequency ranges, often with multiple,
5 separated bands of operation. This paper proposes and demon6
strates an optically tunable cavity backed slot antenna. Through
7 the incorporation of four silicon bridging pieces and a fiber
8 coupled laser, the operating frequency can be tuned between
9 4.2 and 6 GHz. Antenna efficiency has been measured and
10 ranges between 36% and 62% depending upon the combination
11 of frequency and tuning state, with the gain taking values
12 between 4.3 and 6.9 dBi. An effective fabrication process for
13 the incorporation of silicon into the antenna has been described,
14 as well as methods for effectively simulating the optically gen15
erated conductivity. Simulations and measurements show good
16 agreement, and several proposed improvements are proposed for
17 this novel and flexible tuning technology.