Electrostatic analysis of multiconductor transmission lines using an eigenmode projection technique

An eigenmode project technique is adopted to analyze multiconductor transmission lines. The electrostatic capacitance matrix of the tranmission line is directly related to matrix of the quasi-analytical proposed formulation without the need to specify the conductor voltages in a specific sequence to determine the capacitances in a column-wise fashion as in other fully numerical techniques. The proposed technique consists in expanding the static electric field in terms of a complete set of irrotational eigenmodes of a fictitious canonical conducting cavity. The expansion is then used in Maxwell's divergence equation to determine the eigenmode coefficients upon enforcing the boundary conditions of the actual problem (the actual cavity and transmission line conductor surfaces). Results are compared with finite-difference based solution and show excellent agreement.