Analysis of Partial Modifications on Electrically Large Bodies via Characteristic Basis Functions

The efficient analysis of multiple problems that only differ on a small portion of the entire geometry is considered in this work. The method-of-moments (MoM) matrix is compressed with the characteristic basis function method in order to reduce its size. Once the matrix related to the common part of the geometry (mother structure) has been computed and compressed, several algebraic manipulations are applied in order to speed up the solution of the final system of equations. Thus, the computation of the total structure, which comprises the mother-structure plus an additional geometric element, can be efficiently accomplished. The method is illustrated with the analysis of an on-board antenna on a helicopter, where multiple positions of the rotor blades are analyzed.