An L/S Multi-Band Shared-Aperture Circularly Polarized Antenna

In this paper, an L/S multi-band shared-aperture circularly polarized antenna is proposed. Generally, a circularly polarized wave can be implemented by feeding four radiation patches with 90° phase difference in turn. For each frequency band (B1 and B3) in the L-band, four patches are fed by probes connected to their feeding network respectively, which is composed mainly of three Wilkinson power dividers. In S-band, four patches are also fed by probes connected to a feeding network, but, the feeding network is composed of two directional couplers and two Wilkinson power dividers to realize dual-frequency dual-circularly-polarization. The centrosymmetric structure keeps the antenna having a good axial ratio. The simulation results show that the gain of the L/S-band antenna at frequency band of B3 (1.266~1.34 GHz), B1 (1.556~1.566 GHz), Sd (2.05~2.15 GHz) and Su (2.2~2.35 GHz) is more than 3dBi. The impedance bandwidth (VSWR<2) in B3 / B1 / Sd / Su band is about 19.5% / 47.0% 128.8% / 17.8%, respectively.