Millimeter-Wave Bowtie Excited Cavity-Backed Antenna With Improved Aperture

A broadband millimeter-wave cavity-backed antenna, excited by a rounded bowtie dipole, is reported in this letter. To improve the radiation patterns and the broadside gains, its aperture is optimized by cutting the sections with higher-order modes at lower frequencies away from a large aperture, forming a specific open cavity structure. Simulations show that the antenna can present an impedance bandwidth from 28 to over 50 GHz for SWR ≤ 2, and a bandwidth from 28 to 49 GHz for -10-dB sidelobe level. Measurements agree reasonably well with simulations. Comparisons between the antennas with and without the improved aperture in terms of electric field distribution and radiation patterns clearly show performance enhancement.