Ultra-Thin Metasheet for Dual-Wide-Band Linear to Circular Polarization Conversion With Wide-Angle Performance

Satellite communication systems require dual-band circularly polarized (CP) waves to integrate receiving and transmit antennas into one dual-band terminal. Polarization converters play an important role in such a scenario to convert the incoming linearly polarized (LP) signal into the transmitted CP signal. Wide-band and wide-angle performance for the transmission based dual-band polarization converters has been a challenge. In this paper, a transmission-based linear polarization to circular polarization (LP-to-CP) converter is presented using a very simple and thin metasurface based structure. The proposed metasheet is uni-layered, patterned with a circular diagonal split ring enclosed in the square ring. The idea for dual-band polarization conversion is verified with an example in which x(y) polarization is converted into LHCP(RHCP) in Ku-band (15.25~18.9 GHz), and RHCP(LHCP) in Ka-band (29.7~36.7GHz). The converter performs polarization conversion for both bands over 21% of bandwidth which is very wide. Moreover, it maintains performance over wide-angled oblique incidences. Dual-band performance is analyzed theoretically, numerically, and experimentally. The equivalent circuit model is also presented for the unit cell. This metasheet has simple and low-cost design, wide polarization conversion bandwidths, polarization diversity, and wide-angle performance which are very promising for future communication systems.