Upper and lower bounds on mode capacitances for a large class of anisotropic multilayered microstrip-like transmission lines

In the paper, a simple recurrence formula to obtain the Green´s function for multilayered anisotropic structures, with rectangular boundary conditions involving electric and magnetic walls and open boundaries, allows us to present an unified variational approach in the spectral domain to find both upper and lower bounds on the mode capacitances of a large class of planar transmission structures. Very accurate results are obtained by using appropriate trial functions to approximate the surface charge density on the strips and the interface potential distribution for several significant MIC configurations.