| Scattering analysis of targets is an important topic in the field of computational electromagnetism.Specifically,scattering analysis of structures composed of mixed mediums is always the emphasis as well as the aporia for researchers.Based on surface integral equations(SIE),the paper analyzes scattering properties of three kinds of periodic targets: perfectly electric conductors(PEC),homogeneous dielectrics and composite metallic and dielectric structures and both method of moment(MoM)and synthetic basis functions method(SBFM)are adopted to solve these equations.As a classical algorithm,MoM is used here to validate the accuracy and efficiency of SBFM,which is the emphasis and core of this paper.All the work in the paper can be divided into the following three parts.In the first part,basical electromagnetic theories of scattering analysis are introduced.And based on this,SIEs of PECs,dielectrics and mixed structures are deduced in detail.Then,MoM is used to calculate the scattering properties of the three kinds of targets listed above in combination with EFIE,PMCHW equation and EFIE-PMCHW equation respectively.Moreover,the paper also gives some computational formulas on vectors.In the second part,the principles of SBFM are introduced firstly.Then,the paper shows how to analyze the scattering properties of targets with SBFM concretely and gives the method of constructing synthetic functions.More importantly,the paper gives the constrcting formulations of synthetic functions for different targets composed of different mediums on the basis of equivaluence principle.After that,some examples are explored under MoM and SBFM.Through which,accuracy and efficiency of SBFM are fully validated on the one hand.On the other hand,these examples also exhibite advantages of SBFM over MoM in terms of RAM cost and especially for periodic structures.Finally,the paper analyzes the influence of truncation error and external equivalent sources to SBFM’s characteristcs and gives some constructing suggestions on choosing the proper parameters.In the third part,emphasis is laid on applications of SBFM.The paper points out synthetic functions of different blocks relate only to their own geometrical shapes through theoretical analysis and numerical simulation.Then,preprocessing is putforwarded in order to make SBFM suitable for similar periodic structures.The paper also points out all the structures with similar geometrical sub-blocks can be analyzed by SBFM.Finally,the paper ends up with some specific examples.RCS of some typical microstrip patch array is measured through experiment in comparision with that of SBFM which further validates the SBFM’s effectiveness.Further,to incarnate the value of SBFM in reality,the paper introduces a problem with specific background: scattering analysis of targets hidden in jungle and solves it with SBFM. |
