Study Of Field-localization For Application In Microwave Absorption

It has been a human dream for a long time to materialize the control of light,and it is also an important topic in the field of electromagnetic.Artificial microstructure is a new type of material that is periodic arranged with some kind of structural unit,and it has unnatural electromagnetic properties while normal media not possessed.It is generally known that there are much weird phenomenon happened when incident wave interacts with these sub wavelength periodic structures,such as negative refraction,electromagnetic cloaking,inverse doppler shift and sub wavelength diffraction,etc.In addition,the electromagnetic parameters of the metamaterial dependent on the configuration of the unit cell,the size of structure,as well as the permittivity and permeability of the medium we selected hugely.Thus,it provides us a new concept of designing artificial structures with extraordinary electromagnetic properties,and a reliable technical support for realizing the dream of electromagnetic wave manipulated.Field-localization is one of the origin of physical on tuning electromagnetic wave in artificial microstructure.Photonic crystals(PCs)is a typical artificial structures periodic composed of dielectric materials with different refractive index.In this structure,due to the interference superposition of incident wave and scatter field,the field-localization enhanced significantly in PCs.Meanwhile,metamaterial as one of the other classical artificial structure,which is mainly made of metal sheets with different configuration,As a result,the enhancement of field-localization caused by the effect of metal surface plasmon resonance is extremely strong.Two aspects of nonlinear refractive index and microwave absorber based on metamaterial are mainly studied in this paper.And then,the characteristics of field-localization in PCs and the regulation method of microwave absorption about metamaterial is also presented.All in all,The main research work and innovation of this paper is as follows.Firstly,under the condition of the effect nonlinear refractive index coefficient.On the one hand,we calculate the field-localization of a two-dimensional triangle-lattice PC TM waves in the first band based on the effective medium theory.As a result,the electric field mainly concentrated in the media with higher refractive index as square-lattice PCs,but the filling ratio is greater than the one in square-lattice PCs.On the other hand,we also show that the variation of configuration parameters and refractive index difference influence on the field-localization significantly.These two parameters may helpful for predicting the regulation of the effect nonlinear refractive index coefficient on account of the band structure of PCs.Secondly,from the aspects of field-localization and effective electromagnetic parameters,square loop effects on the absorption capacity of microwave absorbing agents is simulated.In turn,with the increasing of refractive index of the background medium,the resonant frequency of the metal microstructure towards lower frequency moving.In addition,the size and distance of the square loop,space between metal square loop and microwave absorbing agents,as well as the incident angle of electromagnetic wave influence on the local field of this composite absorber structure designed is analyzed.