Equivalent Circuits for Nonsymmetric Reciprocal Two Ports Based on Eigenstate Formulation

Equivalent circuit topologies for two-port reciprocal nonsymmetric structures are proposed as an extension of the well-known symmetric lattice network. An eigenstate formulation approach that allows the separation of the eigenmodes in the equivalent circuit, as in the symmetric lattice network, is adopted. Four topologies based on series or parallel immittances with the combined use of some transformers are proposed. Particular cases, such as symmetric networks and parallel and series single elements, are derived from the proposed topologies. Moreover, power dissipation in these topologies is also analyzed. A modification in the reference planes is further introduced to achieve power dissipation orthogonality in the two branches of the circuit, as happens in the symmetric lattice network. Additionally, real transformation ratios for the transformers and nonnegative real parts for the immittances are obtained. Finally, the equivalent circuit is extracted for a complementary strip slot with different degrees of asymmetry. This illustrative example confirms the usefulness of the proposed topologies, which can be regarded as an extension of the symmetric lattice network, since they preserve the eigenstate decomposition.