Broadband Millimeter-Wave Short Backfire Antenna With Bowtie Exciter

A broadband millimeter-wave short backfire antenna with a rounded bowtie exciter is reported in this letter. Simulations and measurements show that the bowtie exciter can provide good illumination to a large antenna aperture, and the elliptical composite cavity can enhance the operating bandwidth to the most extent. Investigations show that the antenna can present a bandwidth from 27.6 to 42.5 GHz for -10-dB sidelobe level (SLL), from 27.6 to over 50 GHz for standing-wave ratio (SWR) ≤ 2, and a broadside gain of 14.3 ~ 18.2 dBi. Electric field distributions over the antenna aperture are given to clearly show its operating principles. Studies on six critical parameters are performed for practical designs.