Investigation of a Frequency-Selective Surface Based on a Planar Mushroom-Shaped Metamaterial with an Electronically Tunable Stopband
A design of a band-stop frequency-selective surface based on a planar mushroom-shaped metamaterial with an electronically tunable stopband has been proposed and investigated. The results of numerical simulation and experimental measurements of the parameters of a finite section of the metamaterial with mounted varicaps are presented. These results illustrate the shift of the structure stopband occurring simultaneously with a change in the capacitance of the lumped elements. Frequency dependences of the inherent dielectric parameters have been obtained. They indicate the presence of negative values of the effective permittivity and effective permeability of the proposed structure and the presence of the surface impedance that significantly exceeds the free-space characteristic impedance and is frequency-tunable.