A new method to compute the fundamental mode resonant frequencies of microstrip annular rings

Abstract

The aim of this paper is the evaluation of the resonant frequencies of the fundamental mode of a microstrip annular ring resonator whose geometry is shown. We propose a new method to evaluate the resonant frequency of the fundamental mode of an annular ring; in particular we expanded the unknown current densities according to a set of functions factorising the right edge behaviour of the unknowns in order to accelerate the convergence of the series.