Direct connection of Uni-Traveling-Carrier Photodiodes to antennas for frequency reconfigurable Fiber-Radio transmission in the Ka band

A compact photonically-driven wireless emitter based on a Uni-Traveling-Carrier photodiode (UTC-PD) which directly connects to a planar folded dipole antenna is presented. The design exploits the dependence of the UTC-PD output impedance with the reverse bias voltage to provide maximum power transfer via conjugate impedance matching at different operative frequencies within the Ka band (26.5 - 40 GHz) with 6 dB antenna directivity and 1 GHz 10 dB return loss channel width. Electro-optical transmission measurements confirm that the photodiode responsivity is maintained throughout the whole voltage swing used for reconfigurability.