In this work the quasi-static spectral domain approach (SDA) applicable to a lossy multilayer CPW that incorporates
two-layer model of a conductor thickness and the concept of effective permeability due to magnetic field penetration in an imperfect conductor is used to account low frequency dispersion analysis. The accuracy of formulation is comparable to that of HFSS and CST, without using complex and time consuming full-wave methods. The results of CST for epsilonƐ<sub>eff</sub> , Z<sub>o</sub> of multilayer CPW, in the frequency range 100 MHz – 10 GHz, deviate from results of HFSS up to 1.34% and 2.37% respectively; whereas corresponding deviations of present formulation are 4.15% and 2.22%.
In this paper we have presented a modified dispersion model which is applicable from DC to THz frequency range for
microstrip line. We have accounted the finite strip thickness in dispersion formula of Kirschning and Jenson. We have
compared the results of this model with EM simulator HFSS and the average deviation is within 1%.