Alternative Construction of the Coupling Matrix of Filters With Non-Paraconjugate Transmission Zeros

An alternative method is proposed for constructing the coupling matrix of a filter having a transfer function with non-paraconjugate transmission zeros. The conversion formulas from the scattering matrix to the admittance matrix are derived under the only conditions of passiveness, losslessness and reciprocity. The main benefit of this method is that it allows, for the first time, to design all-pass filters using the coupling matrix technique.