1. A method of modeling capacitance for a subject structure comprising a pair of long conductors surrounded by a dielectric material and supported by a substrate, wherein the capacitance of the conductors is a function of current frequency, wherein the method includes the steps of: characterizing the surrounding dielectric material as a first dielectric with a first permittivity (ε 1 ) and the substrate as a second dielectric with a second permittivity (ε 2 ); determining a reflection coefficient for the subject structure and a basis structure based on the first and second permittivities (ε 1 , ε 2 ); determining a minor capacitance for the basis structure; and computing a capacitance of the subject structure based on the reflection coefficients and the mirror capacitance.