Two-port-equivalent circuits are widely used in radio frequency (RF) and microwave circuit design to describe the electrical behavior of both active and passive devices. A two-port network (whose elements are expressed through the impedance Z-parameters, admittance Y parameters, or hybrid H-parameters) is most suitable to characterize the nonlinear properties of the active devices, bipolar or field-effect transistors, when designing power amplifiers or oscillators. Transmission ABCD-parameters of a two-port network are very convenient for designing the distributed circuit as transmission lines or cascaded elements. Scattering S-parameters are used to simplify the measurement procedure.

This chapter discusses the main properties of two-port network parameters, as well as the ratios between the different systems. In addition, examples are given to illustrate how to best analyze power amplifiers and oscillators. The final part of this chapter describes the transmission line and its main parameters.

Reproduced from the book RF and Microwave Power Amplifier Design. Copyright 2005 The McGraw-Hill Companies. Reproduced by permission of The McGraw-Hill Companies. Written permission from The McGraw-Hill Companies is required for all other uses.