The present invention provides multidimensional stacked photonic band gap crystal structures improving the performance of current planar monolithic antennas and RF filters by forbidding radiation from coupling into the substrate thereby significantly enhancing radiation efficiency and bandwidth....http://www.google.com/patents/US5739796?utm_source=gb-gplus-sharePatent US5739796 - Ultra-wideband photonic band gap crystal having selectable and controllable bad gaps and methods for achieving photonic band gaps 
