BeiDou navigation terminal multi-mode asymmetric slots circularly polarized microstrip antenna

A novel multi-model, asymmetric slots microstrip antenna of BeiDou navigation system terminal is researched and proposed. It is a compact and right-handed circularly polarized (RHCP) antenna applied with reactive impedance surface (RIS) and complementary split-ring resonators (CSRR). Multi-mode is achieved by two layers stacked circular patches, fed by a single coaxial probe at axis location of patches to generate RHCP radiation by asymmetric slots. The proposed antenna results are: 10-dB impedance bandwidth (BW) =23MHz of B3 band (1250.618MHz-1286.423MHz), 10-dB impedance BW=30.9MHz of B1 band (1559.052MHz-1591.788MHz); 3dB axial ratio (AR) BW=8.6MHz of B3 band, 3dB AR BW=16.5MHz of B1 band; maximum gains are 1.94dB of B3 band at 1.27GHz and 5.4dB of B1 band at 1.58GHz. The multi-mode antenna can work in GPS and Galileo satellite navigation system terminals, apart from BeiDou navigation system. The antenna overall volume is 0.27λ0 × 0.27 λ0 × 0.035 λ0 at 1.27GHz.