Compact High Efficiency Terahertz Filtering Antenna with Low Cross-Polarization Based on the Mixed-Mode Cavity

This paper investigates a D-band high-efficiency filtering antenna with low cross-polarization, which consists of a mixed-mode cavity, a TE440-mode cavity and a slot array. The mixed-mode cavity is deployed for achieving filtering power dividing. Hence, a compact size and high radiation efficiency are achieved for terahertz antenna applications. For verification, a 140-GHz 4×4 filtering slot array is fabricated and measured. The measured gain varies from 17.4 to 18.51 dBi within 16.72 FBW (125.7-148.63 GHz), and the peak aperture and radiation efficiencies are about 77.25% and 96.46%. In addition, the suppression level in stopband is higher than 39 dB.