Annular slot fed cavity antenna

Abstract

Annular slot antenna is a good planar antenna, but the side lobe level in E-plane is very high and aperture efficiency is lower than 30%. It was shown that by modifying the antenna structure and adding a dielectric radome and conductor ring above the slot, the radiation characteristics will improve significantly. A new structure of combination of annular slot antenna and microstrip patches inside an open cavity is introduced which can be optimized to reduce the amount of back radiation. By changing the dimension of patches, one can equalize the radiation patterns in the two principle planes.