A Novel Approach to Analyse the Band Gap of Mushroom-like Electromagnetic Band Gap Structure

In this paper, a novel approach to analyse the electromagnetic band gap (EBG) structure is proposed. The structure consists of metal through-hole, top metal patch, and dielectric medium slab. Different distribution states of surface current on metal for two adjacent units are investigated and two major resonance states are proposed. Each band gap of the structure corresponding to one resonance state at least. The simulation illustrates that a wider band gap occurs when the frequencies corresponding to the resonance states are brought closer together. Therefore, it can be used as an effective method to analyse the band gap variations based on the resonant state of the structure. The finite-difference time-domain (FDTD) method is used to calculate the distributions of finite-period surface current to verify the result.