Bandwidth enhancement of circular polarization generated from circular waveguide and L-shaped probe

A combination of an L-shaped probe and square waveguide generates circular polarization. In this paper, the authors reports a generation by a L-shaped probe and a circular waveguide. Furthermore, a reduction of the higher-order TM mode limiting the bandwidth in axial ratio and impedance characteristics is discussed. Finally, validity as a CP-UWB antenna is also discussed.