Dipole antennas used with all-dielectric, woodpile photonic-bandgap reflectors: Gain, field patterns, and input impedance

A slab of “woodpile” photonic-bandgap (PBG) material is examined as a planar, all-dielectric reflector for a dipole/monopole antenna. Gain, field patterns, and input impedance are obtained using full electromagnetic calculations based on the finite-difference time-domain (FDTD) method and measurements. Of particular interest is the dependence of these parameters on the distance of the monopole in front of the PBG slab and the location of the monopole relative to the structure of the unit cell of the PBG material. The previously introduced “reflection plane concept” for the PBG material is shown to be a useful design tool for this type of antenna. Additional measured results demonstrate that radiation from an antenna is indeed reduced to a low level when it is placed within a finite volume of PBG material and excited at a frequency within the bandgap of the material.