Electromagnetic band-gap structures for multiband mitigation of resonant modes in parallel-plate waveguides

A novel electromagnetic band-gap structure (EBG), whose surface impedance is primarily controlled by its inductance per unit area, is presented. This EBG, which exhibits two wide forbidden band-gaps at very low frequencies, is applied to mitigating resonant modes in parallel-plate waveguides. It is shown that the two forbidden band-gaps can either be controlled independently by varying the physical separation between adjacent patches or simultaneously by varying the number of turns of the spiral inductor used in the patch of the unit cell.