Dual Circularly Polarized Tri-Resonances Ultrawideband Metasurface Antenna for C-Band Satellite Communications

A novel ultrawideband metasurface antenna with dual circular polarization is proposed in this letter. The high, low, and medium circular polarization (CP) mode frequencies of the antenna are generated through the radiation metamaterial patch, the 3/4 ring feed network, and the coupling between them, respectively. The characteristic modes of low and mid frequency exhibit a broad frequency coverage, ensuring that the antenna's entire operating band is continuous and broadband. The antenna is fed by a low dispersion annular microstrip cross slot coupling network with broadband approximate 90° phase difference. The dimensions of the proposed antenna are 0.73λ × 0.73λ × 0.066λ. The overlap impedance bandwidths in simulations and measurements are 81.01% of left-handed circular polarization (LHCP, 3.54 GHz to 8.36 GHz) and 81.92% of right-handed circular polarization (RHCP, 3.51 GHz to 8.38 GHz). The overlap axial ratio bandwidth (ARBW) is 64.74% (LHCP, 3.52 GHz to 6.89 GHz) and 62.97% (RHCP, 3.58 GHz to 6.87GHz), respectively. This broad AR bandwidth is sufficient to cover uplink and downlink transmission frequencies of C-band satellite communications.