Reconfigurable electromagnetic frequency selective surface with high Q-factor transmission resonance

We analyze a planar array composed from a normally magnetized ferrite substrate and metallization in the form of two concentric metal rings in a square cell. This structure possesses a high Q-factor transmission resonance and can be projected with two types of electromagnetic control. The first type is shifting of the resonance frequency of the trapped-mode and the second one is switching from a very high to a low level of transmission by a dc magnetic field. The characteristics of the array are investigated firstly by group theoretical methods and then some numerical results are presented using two different full-wave numerical methods.