Waveguide-Floquet Mapping Using Surface Susceptibilities for Passive and Active Metasurface Unit-Cell Characterization

• Published in: IEEE transactions on antennas and propagation Vol. 72; no. 9; pp. 7110 - 7121
• Main Authors: Sakyi, Papa, Dugan, Jordan, Kundu, Debidas, Smy, Tom J., Gupta, Shulabh
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.09.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Angle of reflection; Antennas and propagation; Floquet modes; generalized sheet transition conditions (GSTCs); Incidence angle; Mapping; metasurface; Metasurfaces; Optical waveguides; Planar waveguides; Rectangular waveguides; Resonators; Scattering; surface susceptibilities; Surface waves; Unit cell; unit-cell simulations
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2024.3433601

A simple waveguide-Floquet mapping is proposed and theoretically investigated that links the scattering response of a sub-wavelength metasurface unit cell under an infinite periodic array configuration and when measured inside a shielded rectangular waveguide environment. This mapping is based on extracting the effective surface susceptibilities as the fundamental constitutive parameters of the cells, via the generalized sheet transition conditions (GSTCs) of the unit cell using the waveguide measurements, and then reconstructing the unit-cell response at an arbitrary incidence angles. Using two examples of a transmissive Huygens' metasurface and a purely reflective metasurface, the proposed waveguide-Floquet mapping is numerically confirmed to determine the complete angular scattering of the unit cells. The proposed waveguide-Floquet mapping thus represents a simple technique to experimentally determine the angular scattering characteristics of the unit cell using a low-cost effective waveguide measurements.