Circularly polarized broadband waveguide antenna using L-shaped probe

An L-shaped probe can generate circular polarization, combining with surrounding aperture, such as waveguides. And the waveguide antenna using L-shaped probe has broadband characteristics in axial ratio (AR) and input impedance, however cross-polarization (XPOL) is easily generated due to its asymmetrical structure resulting in a narrow azimuth range for circular polarization. This paper discussed a design technique to reduce XPOL generated from a circular waveguide antenna using the L-shaped probe.