Necessary and sufficient conditions for compactness of reciprocal RC two-port networks

Necessary and sufficient conditions are given for the compactness of the open-circuit impedance (or short-circuit admittance) matrix of a passive reciprocal RC two-port network when the specified short-circuit admittance (or open-circuit impedance) matrix of the network is compact. The conditions are applicable to unsymmetrical as well as to symmetrical reciprocal RC two-ports.