Selective Manipulation of Microwaves by a Cascade of Independent Metasurfaces Based on Planar Spirals

We propose a multifunctional cascade metasurface designed for manipulating electromagnetic waves in the microwave frequency range with comprehensive theoretical analysis, design optimization, and experimental validation. A set of electrically thin metasurfaces based on planar spirals with free space impedance is used to manipulate electromagnetic waves. The metasurfaces simultaneously generate distinct, independent, and mutually compatible wave transformations at various frequencies. A multifunctional cascade metasurface integrates several functional devices, including a reflective cross-polarizer, a transmissive cross-polarizer, and a nonreflective absorber. Each designed metasurface has a free space impedance over a sufficiently wide frequency range that encompasses the operating frequencies of all metasurfaces. This attribute guarantees the autonomous and mutually noninterfering functioning of all metasurfaces in the cascade.