Analysis of three multi-layer parallel-coupled lines

A spectral-domain analysis is performed on three multi-layer parallel-coupled lines. The self and mutual capacitances of the structure, the per-unit-length capacitance matrix elements, and the three quasi-TEM mode per-unit-length capacitances are derived explicitly for the first time in terms of capacitances corresponding to arbitrary excitations. The mode impedances of the lines are found to be unequal for lines of equal width unlike previously reported.