LAUSR

A dual-band circularly polarized antenna with a lumped element for global positioning system (GPS) applications is proposed and analyzed in this communication. The proposed antenna mainly consists of a square patch with an annular-ring slot, an inductor, and a metallic reflector. The square patch with the annular-ring slot is excited by a T-shaped microstrip line. This produces the left-handed circular polarization (LHCP) in the GPS L1 (1.563–1.587 GHz) and L2 (1.215–1.240 GHz) bands with the help of the inductor and the metallic reflector. In addition, the antenna with the reflector exhibits a unidirectional radiation in both operating bands. A prototype of the antenna is fabricated and measured to verify the simulation results. The measured results show a wide −10 dB reflection coefficient bandwidth of 40.57% (1.12–1.69 GHz) and 3 dB axial ratio bandwidths of 6.56% (1.18–1.26 GHz) and 7.74% (1.49–1.61 GHz) in the lower and higher bands, respectively. LHCP gains of 7.72 and 8.11 dBic are also observed at 1.227 and 1.575 GHz, respectively.