Electromagnetic Analysis Of Finite And Curved FSS With Sub-entire Domain Method

To implement the full-wave electromagnetic analysis of finite and curved Frequency SelectiveSurfaces (FSS), the simplified sub-entire domain (SSED) basis function method is modified in thispaper. Cylinders, cones, pyramids and other periodic structures are established by transforming androtating the original element, and several kinds of SSED basis functions are obtained column bycolumn or area by area. Meanwhile, it is easy for SSED method to analyze the electromagneticproperties of large-scale periodic structures due to the advantage of less computing unknowns and lowmemory consumption. Many kinds of FSSs with different elements, different sizes, differentfrequencies of incident wave and different incident angles are analyzed, and the results calculated bythe modified SSED method agree well with those of commercial software, which verifies theeffectiveness and applicability of our modified method. An approximate method based on engineeringmeasurements, which uses the far-field scattering of equivalent plate to normalize the far-fieldscattering of FSS, is introduced to calculate the reflection and transmission coefficients.To discuss the accuracy and efficiency in the electromagnetic scattering analysis of cylindricallycurved periodic structures, some other SED methods with different basis functions including extendedSED (ESED) and accurate SED (ASED) basis functions are modified and compared with themodified SSED method. The advantages and disadvantages of these modified methods are discussedtheoretically through a serious of numerical results. Drawing on the idea of ESED, a new processingtechnique called Tearing SED (TSED) has been proposed, and it can improve the calculation accuracyby dividing the single element into several sub-units so that the number of current basis functions onsingle element is increased.Moreover, as the the finite element method (FEM) is robust in modeling of complex media, thebybrid method named SSED-MoM/FEM has been introduced to analyze periodic structures ofcomplex geometry or complex dielectric composite objects, which expands the application field ofSED methods. The bistatic Radar Cross Sections (RCSs) of some cylindrically curved arraysconsisting of dielectric plates with different patches on top and dielectric FSSs with cross patches aregiven, which verifies the effectiveness of the new hybrid method.