AbstractThis paper deals with a cascade decomposition of a passive 2n‐port network. after a basic discussion relative to complex‐ and unit‐normalized scattering matrices, necessary and sufficient conditions are presented under which given lossless 2n‐portsD1andD2are simultaneously extractable from the front‐ and back‐ends of the passive 2n‐portN, respectively, to leave a passive 2n‐port remainder Ne. Based on these conditions, some relations between the individual and simultaneous extractability ofD1andD2fromNfor both degenerate and non‐degenerate remaindersNeare discussed. the results are presented in terms of scattering as well as impedance matrices and can be considered as an extension of those giv