Mushroom High-Impedance Metasurfaces for Perfect Absorption at Two Angles of Incidence

In this letter, we study the possibility to achieve perfect absorption of TM-polarized plane electromagnetic waves for two incidence angles at the same frequency. The effect was obtained in a high-impedance surface (HIS) also called a mushroom metasurface due to a combination of two types of dissipation losses inside each unit cell of the HIS, dielectric losses, and resistance of lumped loads. The dual-angle perfect absorption is a narrowband resonance effect. It was shown analytically that one can completely suppress the reflection at two predefined angles of incidence. This result was confirmed by numerical simulations of a practical (realistic and affordable) structure.