Closed-form asymptotic extraction method for coupled microstrip lines

Abstract

The effective dielectric constants of a symmetric coupled microstrip line operating in the dominant mode are solved by using a closed-form formula of the asymptotic part of the impedance matrix elements, Using this asymptotic closed-form solution, the finite upper limit for numerical integration in the evaluation of the impedance matrix elements is significantly reduced, This results in improved computational efficiency for determining the epsilon(reff) Of a coupled microstrip line while retaining a good accuracy compared to the conventional spectral domain approach (SDA).