A circular patch fed by a switch line balun with printed L-probes for broadband CP performance

A wideband circularly polarized microstrip patch antenna is designed, fabricated and tested. Utilizing a wideband 90° planar balun designed with switch line structure, the antenna fed by dual printed L-probes is able to provide good performance in terms of both impedance bandwidth of 45% and axial ratio bandwidth of 41%. Return loss, axial ratio, and radiation patterns are presented in the paper, and the simulated and measured results show good agreements.