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. Measurements show that the antenna can present a bandwidth from 56.2 to 65 GHz for a reflection coefficient S11 ≤ -10 dB as well as for an axial ratio (AR) ≤ 3 dB, and the 10.03-dBi average gain is achieved. This design yields good directional radiation patterns. Studies on several critical parameters are performed for practical designs.