A novel tunable metasurface for filtering the electromagnetic waves

In this study, a novel tunable metasurface is designed in order to filter the electromagnetic waves. The single-frequency window-shaped structure is enhanced to have dual-frequency by loading a gap in order to filter the electromagnetic waves. An epsilon-negative (ENG) unit cell is designed to form the metasurface. The parameter retrieval for the effective permittivity and permeability is performed using a version of the Nicholson-Ross-Weir (NRW) algorithm, which is improved by implementing the Kramers-Kronig relationship. The parametric analyses are also performed as regards the geometrical and material properties. The simulations are conducted via CST Microwave Studio, which is based on Finite Integration Method (FIM).