A new structure based on a semi-circular photonic crystal is proposed to achieve asymmetric light propagation. The semi-circular photonic crystal structure proposed in this paper is a deformation of a two-dimensional conventional square photonic crystal. Through the directional bandgap of the semi-circular photonic crystal, the light from one direction can transfer to the other side, but the light from the opposite direction cannot. A high contrast ratio is obtained by designing the constitutive parameters of the photonic crystal and choosing the suitable light frequency. This structure promises a significant potential in optical integration and other areas.
A combined ME composite structure is made of several cylindrical layered composites in series or parallel connection.Due to the cylindrical structure,the combined structure does not need more space.The characteristics of multi-resonance frequencies have been studied.Each resonance frequency of the structure can be adjusted by changing the cylinder diameter of the corresponding cylindrical layered composites.The number of resonance frequencies increases as the number of cylindrical layered composites increases.The multi-resonance frequencies behavior makes these cylindrical layered composite structures suitable for applications in multifuctional devices with multi-frequencies operation.
