Application And Research Of The Synthetic-functions Approach In The Analysis Of Electromagnetic Scattering Of Targets

The purpose of this paper is to analyse electromagnetic scattering characteristic of targets, and the study object is synthetic basic functions method(SBFM). Firstly, method of moment(MoM) based on RWG basic function and Galerkin method is introduced and realized. Then, synthetic basic functions method(SBFM) is studied which can be used to solve surface integral equation(SIE) efficiently and accurately. Lastly, the algorithm is used for the analysis of complicated objects and antenna array.At first, based on equivalence theorem and boundary condition, surface integral equation(SIE) is deduced which is used to solve perfectly conducting objects, and combined field surface integral equation(JMCFIE) is deduced which is used to solve homogeneous electric objects and EFIE-CFIE-JMCFIE is deduced which is used to solve composite conducting and dielectric objects. Besides, theses integral eaquations are solved by using method of moment(Mo M) to analyse the corresponding electromagnetic scattering problems. About the singularity in the solving process, three methods are introduced, including singularity extraction technique, Duffy coordinate transformations and nine-point integration method. Finally, nine-point integration method is chosed to evaluate singular integral by comparing and analysing the computing result of these three methods, considering the applicability of programming as well.Then, synthetic basic functions method(SBFM) is studied intensively and introduced to analyse electromagnetic scattering of targets, based on the good understanding and realization of traditional method of moment(MoM). Firstly, the method accomplishes regional partition of the geometrical structure of the model, and brings an equivalent current source to take the coupling between elements into consideration, thus the space of the SBF is obtained from the response matrix via a procedure based on the singular-value decomposition. Compared with the conventional MoM, the method uses synthetic functions as basic functions and only a small number of these functions are required to obtain an accurate solution. Therefore, the overall number of unknowns is drastically reduced with consequent impact on storage and solution time.Besides, the characteristics of synthetic basic functions method(SBFM) are further studied. There are three parameters to set in the solving process, including the form of sources and their placement, and the threshold of singular-value ratio. Then, this paper is focused on studing how these three parameters effect the computing quantity and precision. Meawhile, the application field of the algorithm is expanded, which is used for the analysis of electromagnetic scattering of connecting arbitrary complex objects.At last, one port model and several ports model are introduced to analyse the basic scattering theory of general antenna and antenna array, and the conclusion that the scattering of antenna includes the antenna mode scattering and structural mode scattering is made. Combined with the characteristic that synthetic basic functions method(SBFM) is proper to analyse periodic structures, synthetic basic functions method(SBFM) is used to analyse electromagnetic scattering of antenna array. Besides, the way how array distance, incident frequence, incident angle and the array number effect structural mode scattering is further studied.