Millimeter-wave cavity-backed patch-slot dipole for circularly polarized radiation

A novel millimeter-wave antenna for circularly polarized (CP) radiation is presented. The proposed antenna is composed of a patch dipole and a slot dipole, and it is realized by a plated through hole printed technique on a microwave substrate. Simulations show that the antenna can present a bandwidth from 55.8 to 65.3 GHz for a reflection coefficient (S₁₁) ≤ -10 dB as well as for an axial ratio (AR) ≤ 3dB, and the 9.6 dBi average gain is achieved. This design yields good directional radiation patterns and low fabrication cost. Studies on several critical parameters are performed for practical designs.