GIFFT: A Fast Solver for Modeling Sources in a Metamaterial Environment of Finite Size

The GIFFT (Green´s function interpolation and FFT) algorithm is one of a class of fast solvers for large periodic structures. The GIFFT algorithm is a modification of the adaptive integral method (AIM), a technique based on the projection of subdomain basis functions onto a rectangular grid. This paper extends the GIFFT algorithm to allow for a complete numerical analysis of a periodic structure excited by dipole source. In addition to reducing the computational burden associated with large periodic structures, GIFFT now permits modeling these structures with source and defect elements. It is important to note that, although a metamaterial layer with a dipole antenna excitation is considered, as per the extended GIFFT algorithm, defect elements could be considered as well