Research On Metamaterial Device For Manipulation Of Waves Based On Optics Transformation

Based on the form-invariance of Maxwell's equations under coordinate transformations,optics transformation theory can realize manipulation of electromagnetic waves by converting space transformation to equivalent constitutive paramters tranformation.Optics transformation theory has attracted more attentions of scientists in optics and electromagnetics since it was proposed,and has supplied people with effective approach and method to design metamaterial device with special electromagnetic properties.Based on theory of optics transformation,various devices for manipulation of waves have been proposed.These devices could possess potentional applications in military camouflage and electromagnetic engineering fields.However,the constitutive parameters of the devices based on theory of optics transformation are complicated,and need approximated and simplified process to practically realize.Therefore,meanwhile exploring the devices with different electromagnetic properties,people also focus on simplifying the parameters of devices previously proposed.Research on metamaterial device for manipulation of waves based on theory of optics transformation is carried out in this thesis,including mechanism analysis and verification.The main contents are as following:1.Simplification of constitutive parameters for electromagnetic cloaks is investigated.First,different methods are employed to simplify the parameters of cylindrical complementary cloaks,and invisible properties of the cloaks with simplified parameters are analyzed.Second,design and simplification for polygonal cavity cloak with homogenous medium is elaborated,and invisible properties of cloak with ideal and simplified parameters are analyzed.In addition,the sample constructed with normal dielectrics FR4 and F4 B is prepared and measured to experimentally validate the invisible performance.2.Multifunctional devices based on optics transformation are investigated.First,multifunctional devices with cylindrical and polygonal structure,which can be used as cloak,transparent device and transformation device,are proposed.Meanwhile,the implementation of polygonal multifunctional device using layered isotropic medium is analyzed based on effective medium theory.Finally,full wave simulations are carried out to validate the electromagnetic invisibility,transparency and transformation properties of multifunctional devices,and effects of loss tangents on the electromagnetic properties are also investigated.3.Based on optics transformation,the devices which can make the scattering field of object rotatable and transformed are proposed.First,two structures of rotatable and magnified device with complementary and positive medium are proposed.These devices can make the scattered fields of coated objects equivalent to that of magnified object with given rotatable angle.Second,rotatable and minified device which can visually rotate and minify the coated objects by manipulating scattered fields is proposed.Finally,full wave simulations are carried out to validate the electromagnetic properties of above devices.4.Based on composite optics transformation,shifted and transformed devices are proposed.Four kinds of devices with different transformation functions are investigated.These devices not only can make the scattering fields of coated object equivalent to that of object with same,linearly magnified,minified or another shape respectively,but also can make the scattering fields of coated object shifted in two dimensions.Finally,constitutive parameter of shifted device with positive medium is simplified,which can lay theoretical foundation for practical realization of shifted devices.5.Based on finite embedded optics transformation,wave bender,splitter and waveguide bending connector with complementary medium are designed and investigated.To solve the problems of small bending angle with long tip,the volume of waveguide bending connector is compressed by using two steps of optics transformation.Finally,full wave simulations are carried out to validate the properties of manipulating wave bending of above devices.These research results broaden the applications of optics transformation in fields of wave manipulation,strengthen the comprehension of the mechanism of the wave manipulation,and provide fundamental basis for transformation of the metamaterial device to practical application.