Iterative Physical Optics Algorithm For Open Cavity RCS

With the development of electromagnetics and the demand for military applications,especially the research on stealth and anti stealth technology,the analysis and prediction of the target Radar Cross Sections(RCS)has long been an important subject in the field of electromagnetic field theory.Open cavity structure is one of the main sources of scattering of the target,particularly concerned about its RCS analysis.Therefore,analysis and prediction RCS open cavity has become a very challenging problem of all countries in the world of stealth and anti stealth technology.This paper,based on the iterative physical optics method,combines the Forward-Backward technology,the Domain Decomposition Method(DDM)and the adaptive cross approximation(ACA)to study the RCS of the opening cavity.The main research contents are as follows:Firstly,the scattering mechanism of open cavity structures and various methods of calculating the scattering of open cavity are introduced and discussed,and the advantages and disadvantages of each algorithm are analyzed.The principle and program realization of Iterative Physical Optics(IPO)are discussed and studied.Secondly,The IPO method based on RWG basis function expansion and its program implementation are deeply studied,which lays the foundation for the realization of the following IPO fast algorithm.Aiming at the slow convergence of IPO method,the forward and backward technology is used to accelerate the convergence of iteration.Then,combined with DDM,the effective calculation of the open cavity with the inner shadow area is realized.The numerical example proves the correctness of the above method.Finally,the ACA subsection compression technique is introduced to accelerate the filling of IPO matrix and the solution of the equations,and the consumption of computational memory is significantly reduced.As a compression method for fast filling matrix elements,ACA algorithm has been widely used in the analysis of electromagnetic scattering problems in recent years.This method is not directly related to the geometry of the cavity,the form of integral and the selection of basic functions.It is a pure mathematical method to improve the computing speed by linear algebra operation of the matrix.The NURBS modeling method is used to group the ACA,so that the shape of the group is regular and the boundary is clearer.The numerical example shows that when the ACA threshold value is reasonable,the method can guarantee the accuracy of the calculation and reduce the memory consumption and the calculation time significantly.