Design of one-dimensional dielectric and magnetic photonic crystal filters with broad omnidirectional filtering band

A new kind of one-dimensional (1D) photonic crystal (PC) filter is reported in this paper. This kind of a filter is a dimerlike heterostructure constructed by two 1D dielectric and magnetic PCs. Compared with traditional filters based upon 1D pure dielectric PCs, the new one has the advantage of extending the omnidirectional filtering (ODF) band and simplifying the structure due to its large wave impedance contrast between the composites and the reasonable arrangement of the layer thicknesses and the number of periods. To design such a filter, we adopted a combined method by the transmission matrix method and the decimal genetic algorithm, and finally we obtained a high-precision 1D PC filter design which not only shows a very broad relative ODF band of 1.496, but also has a simple structure with less total number of layers and less total thickness. The simplification of structure is conductive to device fabrication. Besides, an example with low dispersive and low dissipative magnetic material for microwave application is also discussed.