275-GHz Planar High-Gain Resonant Cavity Antenna with Effective Medium

In this paper, we present a planar high-gain resonant cavity antenna (RCA) with an integrated waveguide feed for the WR-3 frequency band from 220-330 GHz. The conventional extended hemispherical lens and resonant air cavity are replaced by two effective medium layers of cylindrical hole arrays, which can be fabricated by direct laser drilling on both sides of a high-resistivity float-zone (HRFZ) silicon wafer. The proposed design presents an advantage particularly in its low profile, with an overall thickness of only two wavelengths. The lens antenna is designed through full-wave simulations, and the achieved results suggest a maximum broadside gain of 20 dBi at 275 GHz, with a 3-dB bandwidth of around 18%.