A Wideband Double Circularly Polarized Slot Antenna with Unidirectional Patterns

A broadband double circularly polarized (CP) square slot antenna is proposed in this paper. This antenna has a simple structure and compact size. The structure of the antenna is an inverted planar structure paralleling with the ground. It has two ports to generate different CP waves. The designed antenna works around 1.5GHz, which covers the BDS, GPS and GLNOSS band. The results show good performance of impendence bandwidth (IBW) (S11<-l0dB) is approximately 57.2%, the 3-dB AR bandwidth (ARBW) is approximately 43.8%, and the peak gain is about 7.1dBic at 1.4GHz.