Design Charts for Inhomogeneous Coupled Microstrip Lines

Owing to the bear variation of the odd- and even-mode capacitances in terms of the dielectric constant epsilon_r, of the substrate, it has been possible to obtain formulas giving all the electrical characteristics of the Iines for given values of the ratios, width w and separation s of the lines upon height h of the dielectric substrate. Conversely, by means of charts, it is possible to obtain the geometrical dimensions of the Iines, whatever the value of epsilon_r, for the imposed matching impedance and coupling coefficient. The use of these charts is very easy, and the results are the closest to experimental data published to date.