Closed-form expressions for the even-mode capacitance of thick coupled microstriplines

Closed-form expressions for the even-mode capacitance of the coupled microstriplines with finite strip thickness are derived. The expressions are mainly useful in conductor loss evaluations and are suitable for direct use in computer-aided procedures. The approach used utilises the results that were obtained earlier by conformal mapping techniques. The accuracy of these expressions has been checked against numerical results.