“…They have emerged as a direct analog to photonic band-gap (PBG) materials used in the optical regime [1], [2], and have been investigated extensively in recent years with regard to applications in the microwave frequency range [3]. EBG materials composed of periodic metallic elements have been studied [4]- [8] as an alternative to photonic crystals formed by inhomogeneities in a dielectric host medium. Resonant periodic arrays of metallic dipoles and tripoles on low loss dielectric substrate have been recently investigated as EBG filters for microstrip patch antennas and printed circuit applications [9].…”