Optically switched multiband antenna based on Vivaldi structure

In this study, an optically frequency-reconfigurable antenna with multiband characteristics is proposed utilizing photodiodes. It is developed on the basis of a Vivaldi antenna structure, while the composite radiation structure is realized by introducing three parallel branches in the antenna slot. Three photodiodes on the branches function as photoconductive switches to make the antenna reconfigurable at multiple low frequencies and stable at high frequencies. When the illumination irradiates different photodiodes, the proposed antenna is capable to switch between three narrowband modes, including 300 MHz, 677 MHz, and 1.02 GHz. The radiation gain is measured to reach 0.91 dB, 1.69 dB, 2.96 dB, respectively, while the variation in illumination states is 6.82 dB, 9.93 dB, 17.13 dB, respectively. Meanwhile, this antenna can continue to work stably at 3.2–3.8 GHz and 5.1–6.5 GHz regardless of illumination, with the maximum gain of 7.51 dB. Both simulation and experimental results substantiate the feasibility of the proposed design. This antenna design can transmit and shield the signal of specific frequency with optical control, and has good working characteristics at both high and low frequencies. In the future, it has promising application potential of communication and radar integration.