GreenTensor Library: Tool for Calculate Scattering Diagrams and Bistatic RCS in Multilayered Spherical Structures

The article describes the GreenTensor library developed by the authors, which is an open-source tool. The library aims at implementing calculations in the problems of diffraction and excitation of electromagnetic waves on inhomogeneous spherical bodies, in particular, when considering multilayer spherical structures. As an example that allows us to describe the library's operation, the problem of diffraction on a Luneburg lens is considered. The library allows the researcher to specify various electro-physical parameters of a spherical (including layered) structure to calculate both two-position scattering coefficients (RCS) and the corresponding scattering diagrams. The authors also provide a solution to the problem under consideration based on the Ansys Electronics Desktop (HFSS Design) software. This was done to compare the results obtained using the library with the results obtained in HFSS Design. In addition, the authors provide a comparative analysis of the results obtained using the library with the results of fundamental research presented in one of the works of the authors of the last century. The paper provides a link to the library available on the GitHub resource. The specified repository contains examples of executable files implemented in Python. The subfolders with examples contain HFSS models, on the basis of which the calculation results were carried out. The library is not limited to the implementation of the diffraction problem only on the Luneburg lens; it allows you to operate with other various spherical structures - lenses, such as the Maxwell lens, the Eaton-Lipman lens, etc. The problems of absorption of a dielectric on a metal sphere can also be considered.