Optically Induced Conductivity in Silicon for Active Control of a Franklin Array Antenna

Michael Collett, Martin Cryan, Chris Gamlath

Research output: Contribution to conferenceConference Paper

Abstract

Reconfigurability of antennas is highly desirable for a wide range of applications. The ability to tune resonant frequencies, steer patterns and switch polarizations is becoming increasingly crucial to emerging communications standards and technologies. In this paper, we present a novel technique which uses a 980 nm fiber coupled laser diode to actively tune a gold microstrip Franklin array antenna on a silicon substrate. We investigate the effect of illuminating directly on to the silicon dielectric with sufficiently energetic photons to generate a plasma of free charge carriers, thereby increasing the conductivity of the illuminated regions. Measurements and simulated results show that by illuminating the phasing portion of the antenna we can adjust the antenna’s radiation pattern, resonant frequency and polarization. In particular at 6.5 GHz with illumination added, the return loss can be varied from -5 dB to -22 dB and the measured radiated efficiency of the antenna is changed from 1.35 % to 1.62 %, simulated results show that efficiencies of greater than 30% are achievable at 23GHz.
Original languageEnglish
Publication statusPublished - 11 Feb 2015

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