Evaluation of microstrip Green function

A new technique for the evaluation of the microstrip Green function, which is generally represented by time-consuming Sommerfeld integrals, (SIs) is introduced. The Bessel function argument-multiplication theorem is used to expand the integrals into a power series. This representation can drastically improve the convergence of SIs. Numerical examples studied indicate that this series-form of Green function gives extremely accurate results, <0.1% error for all substrates and source-observer distances, using a few terms in the summation series