Study On Theory Of Metamaterials And Design Of Exterior Anti-cloaks

Metamaterial is a macroscopic composite of three-dimensional periodic or pseudo-periodic cellular architecture,which gains its novel electromagnetic properties from its structure rather than directly from its composition.In this dissertation,gradient,index device,invisible cloak and anti-cloak is designed based on relevance fundamental theory in metamaterial reserch fields.Some numerical simulation and experiments in the microwave range have been made to verification the correctness of the theory design.The following aspects are studied:According to the effective medium theory,an algorithm of the effective permittivity of a materials with gradient index is presented.The packing in the capacitor are perforated with periodic circular hole array.By analyzing the effective capacitance of a basic structure,the formulas of effective permittivity are derived.Then compare the computing result with simulation result use the finite difference time domain solver CST Microwave Studio.Combine with the theory of geometeical optics,deflecting lens and focusing lens have been designed with the drilling-hole medium.Numericial simulation results verified the Correctness of the theory design.Based on optical transformation theory,we designed invisible cloak and anti-cloak in cylindrical coordinate.Based on invariant transformations of Maxwell's equations,the transform equation of electromagnetic parameter between virtual space and physics space are drived.In order to avoid singular value of constitutive parameter in cylindrical coordinate and closed object in interior cloak and anti-cloak device,we propose exterior cloak and anti-cloak device in bipolar coordinate,and they perform well and gain ideal results in numerical simulation.Under the constraint of effective medium theory,theoretical analysis and numerical simulation shows that Our study shows using capacitor that metamaterials combining with the theory of effective capacitance caculate effective permittivity a fairly accurate method.Using this very method,combining with the theory of geometeical optics,we designed gradient index device with excellent perfoamance.Meanwhile,transformation optics is a powerful method which can manipulation electromagnetic wave.Based on transformation optics,we desiged invisible cloak and anti-cloak under different orthogonal coordinates,which gachieve desired effect.These deviceextended the research on manipulation electromagnetic wave in metamaterial fileds and have a certain practical application value.