High gain circularly polarized slot antenna based on microstrip-ridge gap waveguide technology

This paper presents a novel circular polarized slot antenna design using microstrip-ridge gap waveguide technology, it possesses the easy manufacturing since it realizes the gap waveguide with PCB process. The antenna is composed of two substrates, by using the ring slot with a shorted strip on the upper substrate and the EBG textures located on the lower substrate, the circular polarized characteristic of the antenna is obtained, the simulated results with CST simulation software show the antenna has the impedance bandwidth of 13.8% (72.1GHz-82.8GHz, |S11|<;-10dB), and the axial ratio is from 75.2GHz-79.9GHz (AR<;3dB) with 6% circular polarization bandwidth. And also the microstrip slot antenna is designed and compared with the antenna in this paper. The compared results give the strong evidence that the microstrip-ridge gap waveguide circular polarized slot antenna has wider bandwidth and higher gain.