200GHz broadband proximity coupled patch antenna

In this paper, we have successfully designed a broadband elevated patch antenna using a new feeding technique. The antenna scheme offers a large operational bandwidth, compatibly with MMICs, eliminates the undesired substrate effects, and maximizes antenna performance on high dielectric substrates. A rectangular patch, elevated above the high dielectric substrate (semi-insulating-GaAs), is used as the main radiator. The patch is excited by electromagnetic coupling using a loop slot, which is formed in the antenna ground plane and located below the patch at the end of the 50 Omega CPW feed line. With this configuration a broadband patch antenna can be realized, and a low dielectric substrate constant can be created, since the antenna substrate is essentially air which is the lowest possible dielectric constant. The antenna was designed to operate at 200 GHz for G-band applications. The simulation and measurement data have shown superior performance over conventional designs with a 10 dB bandwidth of about 13 GHz, from 190.8 GHz to 203.8 GHz, with nearly constant broadside radiation pattern over antenna bandwidth.