Low-Sidelobe Design of Comb-Line Antenna Using Slot Loading for 77 GHz to 81 GHz Radar Applications

Abstract

In this letter, a new type of traveling-wave comb-line array is proposed, which introduces slots notched at the feed part of the elements. The coupling efficiency of each element can be changed by adjusting the depth of the slots without altering the size of the elements when encountering high-conductance elements. The proposed comb-line antenna minimizes the out-of-phase radiation caused by increases in element width and achieves stable radiation patterns in a broadband. Besides, it is also easy to fabricate. The measured impedance bandwidth is 75 GHz to 80.71 GHz (7.3%). The measured sidelobe level is lower than $-$ 19.8 dB across the bandwidth range of 77 GHz to 81 GHz, and the measured peak gain is 14.59 dBi.