Design of a Broadband Circularly-Polarized Single-Layer Metasurface Antenna Using CMA

This paper presents a single layer low profile broadband circularly polarized (CP) metasurface (MTS) antenna fed through a Coplanar Waveguide (CPW). The MTS consists of 3x4 rectangular cells. Contrary to conventional technique based on plotting surface current distribution to demonstrate the CP operation, Characteristic Mode Analysis (CMA) is employed to give more insight into the MTS and explain the CP characteristic. It is revealed that modes 1 and 2 of the MTS have the potential to achieve CP along a wide frequency band. The proposed single-layer antenna has size of 1.0 lambda(0)x1.0 lambda(0)x0.05 lambda(0). The simulated results show 3-dB Axial Ratio band of 13.8% (5.6-6.43GHz), with an impedance bandwidth of 25.1% (4.86-6.26GHz) and a peak gain of 8 dBi.