Dual-band transmissive metasurface with linear to dual-circular polarization conversion simultaneously

Metasurfaces, as two dimensional periodic structures, are an important candidate to manipulate the polarization of electromagnetic (EM) waves. However, there are few reports on the simultaneous realization of wideband dual-circular polarization conversion using transmissive metasurfaces with one periodic structure in measurement. In this paper, we propose a dual-band dual-circular transmissive metasurface (DCT-MS) for polarization conversion. A DCT-MS simultaneously converts linearly polarized (LP) EM waves into left-hand circularly polarized (LHCP) EM waves in a lower band and right-hand circularly polarized (RHCP) EM waves in a higher band. The unit cell of a DCT-MS consists of a thin substrate and two metal patches in the shape of symmetrical arrows above and below the substrate. The simulated results show that LP waves can be converted into LHCP waves from 7.31 GHz to 10.58 GHz with the axial ratio less than 3 dB. Moreover, the RHCP waves can be realized from 14.26 GHz to 17.36 GHz with the same standard. A DCT-MS sample is measured, and the experimental results are in good agreement with the simulation results.