A robust method for the computation of new closed‐form Green's functions for microstrip structures

A robust approach for the computation of new closed‐form Green's functions is considered to calculate the symmetrical microstrip Green's functions. In this method, the surface‐wave poles are first extracted using a recursive contour integration method. Then, the remainder is approximated by a series of complex exponentials using the Prony's method or the generalized pencil‐of‐function method (GPOF) along the extended rooftop shaped path in k_ρ‐plane. Subsequently, an analytical identity is employed to obtain the new spatial‐domain Green's functions. It is observed that this method can evaluate the spatial‐domain Green's functions accurately and efficiently for both near and far fields. In addition, there is no erroneous results in the near‐field region when z ≠ z′ and ρ → 0. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.