RF/Photonic antenna for high capacity wireless communications

This paper proposes the integration of an antenna with a photodetector for high capacity wireless communications. The side-illuminated waveguide photodetector (WGPD) is used to convert the RF-modulated optical power into a microwave signal, which in turn is fed to an antenna. The WGPD is a standard p-i-n device grown oil a semi-insulating InP substrate and fabricated using conventional techniques. The performance of this RF/photonic antenna in the frequency range 17-20 GHz is studied theoretically and experimentally. An equivalent circuit model for tile WGPD is developed to estimate the photodetector impedance as a function of frequency to assist in the impedance matching between the photodetector and the antenna. The agreement between measurement and circuit model results for the WGPD impedance is very good. It is envisioned that a large number of such RF/Photonic antenna elements could be networked together into a star configuration, feeding in and out of a radio hub.