Book excerpt: Theory and Design of Broadband Matching Networks centers on the network theory and its applications to the design of broadband matching networks and amplifiers. Organized into five chapters, this book begins with a description of the foundation of network theory. Chapter 2 gives a fairly complete exposition of the scattering matrix associated with an n-port network. Chapter 3 considers the approximation problem along with a discussion of the approximating functions. Chapter 4 explains the Youla's theory of broadband matching by illustrating every phase of the theory with fully worked out examples. The extension of Youla's theory to active load impedance is taken up in Chapter 5. This book will be useful as a reference for practicing engineers who wish to learn how the modern network theory can be applied to the design of many practical circuits.