Mechanically reconfigurable frequency selective surface with spiral shape and metal resonant unit on-off configuration

Abstract

This invention relates to the field of frequency selective surfaces, specifically to a helical frequency selective surface with a mechanically reconfigurable on / off configuration of a metal resonant unit cell. The surface comprises a substrate and metal unit cells adhered to the substrate surface, the metal unit cells being periodically arranged on the substrate. Each metal unit cell consists of an upper metal layer and a lower insulating substrate stacked together. The metal unit cells are based on an Archimedean double helix, with two helical lines intertwined and stretched outwards by a predetermined width along the helical lines. The two helical structures do not contact each other, and both ends of the helical structures are semicircular, adhered to the substrate. Through uniaxial mechanical stretching, the Archimedean double helix structure undergoes out-of-plane buckling deformation, causing the two sets of helical structures to contact each other, forming a pathway between the metals and achieving an on / off effect. This invention utilizes mechanical stretching deformation to change the on / off configuration of the metal resonant unit cell, creating a three-dimensional helical frequency selective surface that actively and significantly modulates the electromagnetic wave transmission frequency.

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