Novel Broadband Slot-Spiral Antenna for Terahertz Applications

We report a novel broadband slot-spiral antenna that can be integrated with high-electron-mobility transistor (HEMT) terahertz (THz) detectors. The effect of various antenna parameters on the transmission efficiency of the slot-spiral structure at 150–450 GHz is investigated systematically. The performances of the slot-spiral antenna and the spiral antenna both integrated with HEMTs are compared. The results show that the slot-spiral structure has a better transmission and miniaturization capability than the spiral structure. A formula for the responsivity is derived based on the transmission line principle and antenna theory, and results show that the detector responsivity is correlated with the antenna absorptivity. Additionally, guidelines for HEMT THz detector design are proposed. The results of this study indicate the excellent application prospects of the slot-spiral antenna in THz detection and imaging.