Variational method for coplanar waveguide with anisotropic substrates

Abstract
Lower- and Upper- bound stationary expressions are derived for the line capacitance of the general structure of a coplanar waveguide (CPW) with layered anisotropic media for the first time. Numerical examples show the efficiency of the method, and how the margins of error can be contained within a very small range by the lowerand upper-bound calculations.