Spatial domain Green's functions for planar multilayered structures

This paper presents a robust approach for calculating spatial‐domain Green's functions on the interface or close to the interface of planar multilayered microstrip structures with lossless or lossy dielectric materials for a wide range of frequencies and layer thicknesses. We compute the mixed potential Green's functions for distance ρ for 200 points from 0.1 to 10 wavelengths. The CPU is less than 30 s for each frequency on a Pentium‐IV 2.4‐GHz PC. In the case of moderate layer thickness, the fast Fourier transform (FFT) method is introduced to the half‐space extraction method in order to calculate all ρ values of the different radial source‐to‐field separations simultaneously. For thin layers, the results are computed by the contributions of the vertical‐branch cut and the addition of a surface‐wave pole. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 86–91, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20555