A compact wide-band EBG structure utilizing embedded resonant circuits

This letter presents a wide-band electromagnetic bandgap (EBG) structure designed utilizing embedded resonant circuits (ERCs). The EBG structure is a periodic material whose unit cell is composed of a number of small resonant LC circuits. For EBG composed of single resonant LC circuits above the resonant frequency, the structure behaves as a negative permeability material that provides the bandgap behavior. To design a compact wide-band EBG, a structure constructed of three layers of ERC, each having different resonant frequencies separated by layers of impedance inverters, is proposed. The impedance inverter layer is designed using I-shaped metallic inclusions printed in the host medium to achieve a high dielectric material so as to physically reduce the thickness of the quarter wavelength inverters. The design and performance characteristic of a complete EBG structure with isotropic bandgap behavior almost independent of incident angle and polarization state is also demonstrated.