Dual-band circular polarized microstrip antenna for GNSS application

A dual-band circular polarized antenna with broad bandwidth is proposed. Two circular grooves with different radii are carved on the ground to generate two frequency bands. Two rectangular slots are engraved on the outside of the circular groove. By adjusting the length of the two slots, this antenna can radiate right-handed circularly polarized (RHCP) waves at two frequency bands, which can cover GPS L5 (1.176 GHz), L2 (1.227 GHz), L1 (1.575 GHz), BDS, GALILEO, and GLONASS bands. The measured -10 dB bandwidth is 46.3 % (1.13-1.81 GHz) and 3 dB axial ratio bandwidths are 15.6 % (1.11-1.30 GHz) and 17.8 % (1.38-1.65 GHz). The measured gains are 2.51 dBi and 2.67 dBi at 1.2 GHz and 1.56 GHz, respectively.