Substrate Integrated Gap Waveguide Circularly Polarized Slot Antenna

A broadband aperture circularly polarized (CP) antenna based on substrate integrated gap waveguide (SIGW) for millimeter applications is presented. An inclined aperture is etched on the metal layer of the SIGW and excited by transmission microstrip line of SIGW. The mechanism of CP radiation is analyzed briefly in the paper. The simulated results show impedance bandwidth from 24.8 to 31.7 GHz (24.4%) and 3-dB axial ratio bandwidth from 27.3 to 28.8 GHz (5.3%). The design is validated.