All-Dielectric Tapered Rod Antenna With Subwavelength Grating for Terahertz Waves

Dielectric antennas with moderate gain are important in short-range terahertz communication applications. However, achieving moderate gain while maintaining a small antenna footprint is challenging. This letter presents an alldielectric tapered rod antenna with non-uniformly distributed sub-wavelength grating operating over 220 GHz to 330 GHz. The antenna is monolithically integrated with a low-loss substrateless silicon effective-medium-clad waveguide platform. The proposed antenna supports two orthogonal fundamental modes, i.e., the inplane and out-of-plane polarizations. The measured result shows that the realized gain for the two polarizations ranges from 12.7 to 15.5 dBi. Notably, the antenna with grating achieves an average gain enhancement of 1.82 dB compared with the bare tapered rod antenna with the same footprint. This method for improving gain holds great promise for terahertz communications.