In this paper, it is shown that in the solution of the double matching problem given by Carlin and Yarman there does not exist a one-to-one correspondence between the output impedance Zq(s) and the transducer power gain function when the matching network contains the complex transmission zeros contributed by the common factors of the numerator and denominator of Zq(s). Also Youla’s conditions imposed on the chain parameters are extended and applied to the passive, lumped, lossless, and nonreciprocal two-port networks. Based on the above discussion, a CAD method using the chain parameters is proposed to solve the double matching problem where the equalizer may have complex transmission zeros. The result permits us to design a general doubly-matched network, the amplitude and phase of which are both required to be matched. Finally, an example is given to describe the iterative approximation process and its computations.
