High-Gain, Low-Profile, Integrable Planar Lens Antenna at 275 GHz

Terahertz communications require compact, high-gain antennas that can be integrated with sources, as alternative to traditional lenses, which have bulky sizes and lack design flexibility. This paper introduces a high-gain, low-profile silicon cavity antenna integrated with a WR-3 waveguide feed. The antenna consists of a 2-mm thick silicon wafer with non-uniform hole arrays designed to locally control the effective permittivity. The holes are laser-etched on both sides of the silicon wafer, to overcome phase coverage limitations caused by the tapered side walls of the air hole during fabrication. Experimental results confirm a gain of 19 dBi at 275 GHz, with a 3-dB bandwidth of approximately 29%. We further demonstrate that the high-gain antenna can be integrated with a quarter-wave plate for circularly polarized (CP) radiation.