Abstract
An L-shaped probe with a surrounding aperture such as a waveguide can generate circular polarization (CP) waves. Circular waveguide antennas using an L-shaped probe have broadband characteristics both in axial ratio (AR) and in input impedance, however cross-polarization (XPOL) is easily generated due to its asymmetrical structure resulting in a radiation pattern that has narrow CP azimuth range. In this paper, design techniques to reduce the XPOL generated from a circular waveguide antenna using an L-shaped probe are proposed. As a result, XPOL is reduced by around 10 dB, and CP is radiated over a wide angle range of 120 - 150 ° covering frequencies from 7.35 to 9.75 GHz.
