Some Tools for the Analysis and Representation of Linear Two-Port Networks

The so-called image quantities of a two-port network are often found useful when treating power flow and input impedance under different load conditions. The formal analogy between a symmetric reciprocal two-port network and a uniform transmission line is here extended to unsymmetric networks by means of a wave-symmetric transmission line model. If the network is nonreciprocal it can be decomposed into a reciprocal part cascaded with an antireciprocal transition having simple impedance and power transfer properties. It is further shown that by adding reactances in series with a two-port network its image impedances can be made either real or imaginary. The so reactively modified network has an image attentuation that directly determines the maximum power efficiency of the original network.