Combined Method for the Computation of the Doubly Periodic Green's Function

Abstract

The performances of several methods used for the computation of the free space Green's function for doubly periodic arrays are investigated. We make a careful study of these methods, based on accuracy and computing time criteria. We show that none of them is able to fulfil both criteria for a large range of parameters (position in space, wavelength, periods, ... ). Fortunately, it is possible to retain three complementary algorithms. We combine them in order to implement a numerical code that automatically chooses the appropriate algorithm depending on the parameters.