A Compact Dual-Band Circularly-Polarized Antenna with Wide Axial-Ratio Beamwidth for Vehicle GPS Satellite Navigation Application

A compact circularly polarized patch antenna with wide axial-ratio beamwidth (ARBW) operating at dual bands compatible for GPS satellite navigation application is proposed in this paper. The antenna consists of two stacked patches, which account for GPS L 1 band (1575 ± 2 MHz) and L 2 band (1228 ± 2 MHz). To realize significant size miniaturization, four pillars are introduced and strongly coupled to the lower patch. To adjust the beamwidth response of the far-field components, the antenna is backed by a modified metallic cavity, which in turn widen the 3-dB ARBW at two operating bands effectively Finally, the proposed design with excellent performance is realized in a size of 0.368 λ 0 (diameter) and 0.105 λ 0 (height). Simulated and measured results show that the ARBWs at L 1 and L 2 bands are as wide as 173° and 133°, respectively. For practical application, its satisfactory GPS signal receiving capability is also verified by outdoor positioning test.