Location of Surface Wave Poles in Sommerfeld type Integrals: A Mittag-Leffler Expansion Approach

In this paper, the Mittag-Leffler (ML) expansion method is introduced to find surface and leaky wave poles. The ML expansion method replaces the trigonometric functions present in Sommerfeld type integrals with equivalent expansion functions. One of the many applications is to solve for multilayered media Green's functions that are needed to calculate currents on microstrip patch antennas and interconnects. The ML expansion method has been applied and tested on microstrip problems with various dielectric permittivities, for electrically thick and thin substrates and for lossless and lossy cases.