Intertwined spirals for metasurfaces and high impedance surfaces

A broad class of metasurfaces comprised of periodic arrays of interwoven multifilar spiral shaped strips and slots in conducting screens has been developed. The proposed array topologies with truly sub-wavelength unit cells enable efficient control of the unit cell reactance while maintaining excellent angular and polarization stability of their response over extended fractional bandwidths. The distinctive features of such conductor patterns are illustrated in the context of their applications to frequency selective and high impedance surfaces as well as to voltage controlled reconfigurable metasurfaces comprised of intertwined multifilar spirals with embedded pin and varactor diodes.