High efficiency and high gain indium tin oxide optical transparent antenna based on Fabry–Perot cavity

Integrating optical transparent antenna (TA) into glass facilities can strengthen the intelligent interaction of indoor infrastructure and release spatial and aesthetic constraints. This paper proposes the first fully transparent Fabry–Perot cavity (FPC) antenna using indium tin oxide (ITO) film and glass substrates to improve the efficiency and gain. The theory for FPC with lossy transparent partially reflecting surfaces (PRSs) is proposed. The TA is composed of a high efficiency transparent monopole feeding antenna (TMFA) and two transparent PRSs. The PRSs are optimised based on the proposed theory. Additionally, the structure of the TA is optimised to get a good compromise between transparency and radiation efficiency. Multi-resonance cells on the PRSs are designed to improve the bandwidth. The proposed transparent FPC antenna obtains an overall optical transparency of 84% and a peak efficiency of 70.4%. A peak gain of 11.7 dBi is achieved with an aperture size of 2.2$\times 2.2{\lambda }_0^2$, and the 3 dB gain bandwidth spans from 4.9 GHz to 6.3 GHz. Furthermore, the transparent cavity structure makes the proposed antenna can be integrated with indoor double glazing seamlessly.