New Analytical Model for the Dielectric Loss of Microstrip Lines on Multilayer Dielectric Substrates: Effect of Conductor-Dielectric Interphase

Abstract

The existing CAD formulae for dielectric loss of microstrip lines on substrate are complicated and inaccurate at high frequencies. In particular, no closed-form expression has been obtained for the dielectric loss of microstrip lines on multi-layer dielectric substrate by including the conductor-substrate interphase effect, although attempts have been made to study the finite thickness effect of the conductor and dielectric substrate. The present work represents the first attempt to obtain a closed-form CAD formula for the dielectric loss of microstrip lines on dielectric substrates by considering the effect of conductor-substrate interphase. Our simple and accurate model systematically considers the effect of the interphase between the microstrip line and substrate by using a quasi-TEM approach and is shown to be supported by the available experimental data.