Circularly-polarized slotted-patch antennas fed with microstrip-to-slotline baluns

A design for circularly polarized (CP) patch antennas fed with a microstrip-to-slotline balun is described. The CP radiation of the antenna is generated by embedding a cross slot with unequal lengths into the radiating patch, and the balun serves as a differential feeding scheme for the CP slotted-patch antenna. Both simulated and measured results demonstrate that the proposed antenna can offer more symmetrical radiation patterns and lower cross polarization as compared to a same-size patch antenna with an unbalanced feed.