Bandwidth-Enhanced Design of Compact High-Order-Mode Cavity-Backed Slot Antenna

This letter presents an enhanced bandwidth design of a compact high-order-mode (HOM) cavity-backed slot antenna array for V-band communication systems. Pairs of small-distance parallel slots are utilized as radiating elements, which have the merits of enhancing bandwidth by generating electric field perturbations in the cavity. Furthermore, four shorting pins are loaded around the coupling slot to enhance bandwidths as well as to improve the gain of the antenna. Based on studies on the electric field and important parameters, the operation principles of the bandwidth enhancement are analyzed. For the proof of concept, a HOM cavity-backed slot antenna array prototype with four subarrays is fabricated and measured. The measured impedance and 3 dB gain bandwidths are 12.04% [(58.16 to 65.61) GHz] and 13.03% [(58.35 to 66.48) GHz], respectively, with a measured maximum gain of 18.69 dBi and maximum aperture efficiency of 58.1%. The measured results are consistent with simulated results.