AN ALGORITHM FOR CALCULATING GREEN’S FUNCTIONS OF PLANAR, CIRCULAR CYLINDRICAL, AND SPHERICAL MULTILAYER SUBSTRATES

Abstract

We introduce an algorithm for calculating spectral domain Green’s functions of planar, circular, cylindrical, and spherical multilayer structures. The three spectral domain problems are interpreted as multilayer spatial domain problems with electromagnetic sources in the forms of current sheets, tubes, and shells, respectively, and with harmonic spatial variation. The algorithm, which is the same for all three geometries, is based on dividing these three field problems into appropriate subproblems by using equivalence, and on determining the tangential field components at the interfaces between the layers of the structure. The algorithm is implemented into three versions of a Fortran routine called G1DMULT, one version for each geometry. The only difference between the three versions is in two subroutines which calculate the fields due to harmonic current sheets, tubes, and shells, respectively, located in an infinite homogeneous material. We have tested the routine by calculating the properties of microstrip patch antennas and periodic structures.