A method for computing the characteristic impedance of transmission lines using the wave cascade matrix formalism

This work deals with the characterization of the line impedance of uniform transmission lines. Using the Wave Cascade Matrix representation (WCM) of a uniform transmission line as reported by J.A. Reynoso-Hernandez (2003), a new method for determining the line impedance is presented. The method can be used fur any kind of transmission line. To demonstrate the usefulness of the proposed method, the line impedance of coplanar waveguides (CPWs), using SRO20 and SiO2 as the passivation layer is evaluated both in dark conditions and when illuminated by a visible laser.