An ultra-wideband high gain antenna with embedded sleeves and hexagonal cavity

Radar detection and imaging systems need ultra-wideband, high-gain antennas to improve depth resolution and detection range. This paper proposes an ultra-wideband high gain differential patch antenna having a peak gain of 12.9 dBi and an average gain of 11.3 dBi in the bandwidth from 7.2 and 26 GHz. Two sleeves are added around the feeding probes to attain ultra-wideband impedance matching that is explained with an equivalent circuit. A hexagonal cavity with two M-shaped cutouts improves the gain in the broadside direction by redistributing the current and reshaping the antenna's radiation patterns at different frequencies. The antenna's measured S-parameter validates the design and confirms it has an ultra-wide bandwidth. The ultra-wide bandwidth along with the high gain values make the antenna a promising candidate for high-resolution radar systems.