A Review of ABCD ParametersA Review of ABCD Parameters By David Thorson Phonex Corporation his article reviews transmission matrices (ABCD parameters), their definition, and their application in microwave circuit analysis. It presents their relationship to scattering parameters and demonstrates their use by analyzing a popular transistor amplifier circuit. Several parameter sets exist for characterizing linear two-port networks. The most common parameter sets include admittance (y), impedance, (z), hybrid (h), and scattering (s) parameters. Although these sets can be used to describe a linear network with an arbitrary number of ports, this article will only discuss two-port networks. The terminal characteristics of a given two-port are represented by any of these parameter sets as a 2 × 2 matrix with each element ge……