Design of low-profile high-gain wideband circularly polarized low RCS single-layer metasurface antenna using characteristics mode analysis

In this paper, a novel circularly polarized (CP) high-gain low-profile single-layer metasurface (MTS) antenna fed by a coplanar waveguide is presented for wideband low radar cross-section (RCS) applications. Characteristics mode analysis (CMA) technique is employed to simultaneously excite the useful modes rather than using conventional technique to achieve circular polarization in the wideband. By analyzing the characteristics modes of the antenna, gain of the antenna is also improved. Experimental results verify good performance of the proposed antenna with a compact size of 0.67 lambda(0) x 0.67 lambda(0) x 0.040 lambda(0). The measured results of the antenna exhibit UWB impedance bandwidth of 96.93% in the frequency range of 3.7-10.65 GHz and 3 dB axial ratio bandwidth of about 41.8% in the frequency range of 5.3-8.1 GHz. The antenna shows a good radiation pattern with a measured peak gain of 7.9 dBic at 7.97 GHz. The proposed antenna achieves out-of-band scattering suppression in the wide range of 10-24 GHz because of MTS structure with peak RCS reduction of 19 dB at 12 GHz. The proposed antenna can be used for c- and x-band applications.