Wideband and High-Gain Q-Band Substrate Integrated Cavity Antenna and Array

A novel substrate integrated cavity (SIC) antenna element featuring wideband and high-gain performance is presented for millimeter-wave communication in this letter. To acquire a stable radiation performance and wide bandwidth, the
$\mathrm{T}{{\mathrm{M}}_{{211}}}$
mode is utilized in the cavity, and its electromagnetic field distribution is maintained over the operating frequency by an H-shaped patch loaded on the open-ended SIC. The antenna element and a 4 × 4 array are designed and manufactured for the proof of concept. The proposed antenna element has a measured wide bandwidth of 35.67% from 31.31 to 44.91 GHz and a measured peak gain of up to 11.3 dBi. The measured impedance bandwidth of the array is 32.71%, with a maximum gain of 21.8 dBi occurring at 40 GHz. Stable boresight radiation patterns are obtained, and the measured levels of cross polarization are achieved below −30 dB.