ABSTRACT
This chapter focuses on the analysis of doubly periodic metallic arrays to obtain a bandgap from a structure. The control of the bandgap is governed by array parameters such as the type of element, physical dimension, lattice parameters, and dielectric constants of the substrates. The chapter describes the theory of frequency-selective surface (FSS) and planar electromagnetic bandgap (EBG). It discussed the propagation of electromagnetic fields in all planar directions within the bandgap frequencies. For cases at certain frequencies, the photonic crystal will prohibit propagation of an electromagnetic wave at any incident angle, direction, and polarization; this is termed as the absolute photonic bandgap. Research has extended to metallodielectric EBG, which is replacing the periodic high dielectric constant cavities of the photonic crystal with periodic metallic elements. The unique properties and practical uses of FSSs realized over many years have produced an extensive body of work in both academic and industrial sectors.
