Dual-band circularly polarized stacked microstrip antenna over RIS for GPS applications

A compact, dual band, circularly polarized (CP) multilayered stacked microstrip antenna over reactive impedance surface (RIS) is studied and presented in this paper. The CP radiation with compact antenna size is achieved by placing two asymmetric slit square patch (ASSP) and cross-shaped slotted square patch (CSSP) radiators over the RIS. Dual band is achieved by using the CSSP and ASSP stacked patches placed over RIS, fed by a coaxial probe at proper location to generate CP radiation. The measured results of the proposed antenna are 1.61% (1.235-1.255 GHz): L2 band and 1.25% (1.585-1.605 GHz): L1 band for 3-dB axial ratio bandwidth (BW), 2.00% (1.235-1.260 GHz): L2 band and 1.57% (1.580-1.605 GHz): L1 band for 10-dB impedance BW, and 2.68 dBic: L2 band and 4.46 dBic: L1 band for gain at the boresight for compact antenna overall volume of 0.26λ_o × 0.26λ_o × 0.018λ_o at 1.2 GHz.