A Low-Profile Sub-Terahertz Transmit-Array Antenna with High Gain Enhancement

A compact transmit-array (TA) antenna with reduced profile and improved radiation gain is proposed in this paper. The proposed transmitting surface, with a thickness of 0.127 mm (0.042 $\lambda_{0}$ @105 GHz), is employed here to adjust the phase distribution across the aperture of a shortened feed horn. The full TA prototype is fabricated and measured. A 3-dB gain bandwidth of 9.52%, from 100 GHz to 110 GHz, is achieved. The measured maximum gain at 105 GHz is 22.76 dBi, which gets an 8-dB enhancement with respect to the primary feed, without expanding the radiation aperture size. This method considerably reduces the complexity of TA and achieves a much more compact structure.