2-D Leaky-Wave Radiation from 3-D Dielectric Woodpile Electromagnetic Band-Gap Lattices

An original model is here proposed for highly directive radiation from three-dimensional (3-D) Electromagnetic Band-Gap (EBG) dielectric structures excited by an embedded point source. First, a rigorous semi-analytical method for the dispersive analysis of 3-D periodic woodpile crystal is presented and validated. Then, an optimized 3-D periodic woodpile lattice is suitably designed to have a total band-gap region with the higher band edge corresponding to Bloch waves that propagate along the vertical direction of stratification. Furthermore, the modal dispersion in an open 2-D periodic woodpile waveguide composed by a finite number of cells along the vertical dimension has been thoroughly analyzed and its relevant passband and stopband regimes accurately investigated. Finally, the directive radiation of a horizontal dipole embedded within both laterally infinite and laterally truncated open woodpile waveguides has been fully described and characterized in terms of 2-D leaky waves propagating radially from the source within the total bandgap of the 3-D woodpile. The present study provides both physical insight and an effective design tool to new kinds of highly directive 2-D leaky-wave antennas based on 3-D EBG lattices with applications from microwaves to THz.