High-gain mmWave shorted rectangular ring antenna with complementary segmented-cavity backed structure

Abstract

An efficient gain-enhancement technique for millimeter wave (mmWave) planar patch antennas (PPAs) using a novel slot-loaded and segmented-cavity backed structure is newly proposed in this study. By incorporating a main radiator with a rectangular slot and employing a muli-layered segemented-cavity, the proposed antenna design significantly increases antenna gain beyond conventional approaches. Unlike traditional patch antennas or those with shorting pin structures, our gain-enhanced PPA utilizes the rectangular slot to electrically expand the radiation aperture, while the addition of substrate integrated pillars acorss multiple segmented ground layers markedly improves antenna directivity. The strategric use of a segmented cavity not only facilitates flexible impedance matching but also ensures consistent performance within the n257 band, accompanied by minimal gain variation. To verify the gain enhancement from the conventional patch, the proposed antenna was fabricated with a size of 1.03 λ0 × 1.03 λ0 × 0.1 λ0 at 28 GHz. The measured 10-dB impedance bandwidth was 12.14 % with a maximum measured gain of the 11.28 dBi at 28 GHz. Compared to the measured gain of the conventional PPA with the same size, the gain was 39.6 % higher, which represents the highest gain per total antenna volume observed for a single PPA in the mmWave spectrum for high-gain applications, to the best of our knowledge.