A closed form analytical model for the electrical properties of microstrip interconnects

A simple model is presented based on closed-form analytical approximations for the resistance, capacitance, inductance, and conductance of a generic microstrip interconnect. Working in the frequency domain, all the low-frequency lumped circuit and high-frequency transmission line properties can be calculated. As examples, this model is applied to high-frequency reflectivity measurements on Teflon and FR4 printed circuit board microstrips. Agreement to better than 5% up to 1 GHz is obtained by using a dielectric constant of 2.20 and dissipation factor of 0.004 for the Teflon boards and a dielectric constant of 4.9 at 1 MHz with a constant dissipation factor of 0.022 for the FR4 microstrips. This model enables packaging engineers to evaluate the possibilities of an interconnect technology very simply on their personal computers (PCs)