Wideband reflective half- and quarter-wave plate metasurface based on multi-plasmon resonances

In this article, a single-layer reflective anisotropic metasurface (MS) is proposed, which presents both half- and quarter-wave plate operation in different microwave frequency regimes. The unit cell of the proposed metasurface consists of a tilted rectangular plane with triangular ends accompanied by an equidistant-filled triangle on both sides. The unit cell is printed on a dielectric substrate backed by a metallic plane. The proposed meta-plate transforms horizontal polarization into vertical and vice versa in two wide frequency bands, 7.1-15.3 GHz and 19.8-21.7 GHz. Similarly, a linearly polarized (LP) wave is transformed into a circularly polarized (CP) wave and vice versa at 7.9 GHz and 21.8 GHz. The wide bandwidth is acquired through three plasmonic resonances occurring at 8.2 GHz, 12.7 GHz and 20.8 GHz, where the cross-polarization conversion ratio reaches almost 100%. Moreover, quarter and half-wave plate operations occurring at 7.9 GHz and 7.1-15.3 GHz, respectively, are robust to changes in oblique incidence angle (up to 45 degrees) both for transverse-electric (TE) and transverse-magnetic (TM) polarizations. The physical mechanism behind polarization conversion is also explained through surface current distribution. The proposed meta-plate structure is fabricated and validated through experimental measurements. The wide bandwidth, high efficiency, angular stability, and simple structure make the proposed metastructure incredible for numerous microwave applications such as antennas, radars, and satellite communication.