A Transmittive-type Metasurface for Dual-band Linear to Circular Polarization Conversion

In this paper, a transmittive-type dual-band linear (LP)-to-circular Polarization (CP) converter has been reported. The structure can convert the incident LP wave into right-handed circularly polarized wave in two non-adjacent frequency ranges of C and Ku bands. It bears a tri- layer configuration of three concentric square shape split ring resonators having slits oriented along 45° with each other. The simulated results show that the axial ratio of the proposed converter is under 3-dB over the frequency ranges of 4.07-4.15 GHz and 14.19-14.51 GHz. The ellipticity of the structure is - 0.98 and -0.99 at 4.1 GHz and 14.3 GHz, respectively; thereby confirming the right-handed CP nature of the transmitted wave. This transmittive-type metasurface can be easily mountable to a simple dual-band LP antenna to obtain the desired dual-band CP wave for satellite communication system. The structure has the periodicity of λ/5 while maintaining thickness of λ/6.6 w.r.t. the center frequency of the first conversion band.