A novel design of low profile circularly polarized antenna with high gain and wideband characteristics

A novel design of low profile circularly polarized antenna with performances of high gain and broad bandwidths is presented in this paper. Through the method of connecting the radiating patch to the ground plane by the metal wall, the peak gain of the antenna can be achieved as high as 11.8 dBi. Furthermore, In order to improve the axial ratio (AR) and impedance bandwidths, broadband 90 degrees phase-shifter is introduced as feeding network. Annular-ring structure acts as radiating patch instead of circular patch can further improve the AR bandwidths. The measured results show that the antenna possess an impedance (VSWR <= 2) bandwidths of 23.3% ranging from 1.87 GHz to 2.36 GHz, and right-handed circular polarized (RHCP) axial ratio (AR <= 3dB) bandwidths of 24.3% ranging from 1.84 GHz to 2.35 GHz relative to the center frequency of 2.1 GHz, which agree well with simulated results.