A Hybrid Wideband Method for Analysis of Periodic Array

In this study, the frequency and material independent reactions (FMIR) is combined with generalized single source tangential equivalence principle algorithm (GSST-EP A) to calculate the wideband RCS of finite period array structure. By Taylor series expansion of the exponent of Green function, a frequency independent matrix and a frequency dependent phase factor are generated. Therefore, the FMIR can accelerate the frequency sweep and improve the frequency sweep accuracy dynamically, while the memory requirement is large. To deal with this problem, the GSST-EPA can transfer the solution problem on the target to the equivalent surface, so it can improve the matrix condition number and decrease the number of unknowns. The characteristic basis function (CBF) is constructed on the equivalent surface to improve the efficiency of GSST-EPA. A numerical example is shown to prove the accuracy and efficiency of the method.