A Leaky-Wave Approach to Directive Radiation in 3-D Dielectric Woodpile Lattices

In this contribution, the leaky-wave nature of radiation from 3-D periodic dielectric woodpile lattices is demonstrated. First, an investigation of the dispersion properties and total band gap in a Body-Centered Tetragonal (BCT<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>) macro cell is performed. Then, the geometrical parameters of the BCT<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> are optimized in order to locate the upper edge of the band gap at the Z-point of the irreducible Brillouin diagram, corresponding to normal propagation with respect to the woodpile stratification. Finally, the radiative properties of the open woodpile waveguide are analyzed in a transversely truncated structure, when a horizontal electric dipole is properly placed into the lattice, and the enhanced radiation at broadside is explained in terms of a highly directive leaky mode.