Explicit expressions for geometrical dimensions of symmetrical coupled striplines

It is shown how the inverse solution of certain wave-impedance problems can be found explicitly by using Jacobi´s theta functions. It is possible to find directly the geometrical dimensions, given the transmission-line wave-impedance parameters. Inverse formulas for a shielded single stripline and coupled symmetrical striplines are presented. The numerical computations are simplified by the excellent convergence properties of Jacobi´s theta functions.