#### Time-domain Computer Analysis of Non-Linear Hybrid Systems

Wenquan Sui
CRC Press
396 pages; \$99.95, £69.99
ISBN: 0-8493-1396-1

This book is a summary and review of research work on finite-difference time-domain (FDTD) co-simulation for hybrid electromagnetic systems. The numerical co-simulation methods that are described and used in various applications show great potential for many aspects of future electrical system design and analysis. The book includes many of the recent developments in the time-domain co-simulation of hybrid electromagnetic systems and concentrates on techniques for integrating time-domain field solutions, analog circuit analysis and a lumped-in-nature foreign system (like an n-port nonlinear circuit) in a unified solution scheme. The book should serve as a useful reference for researchers, practicing engineers and graduate-level students.

After a general introduction, Chapter 2 introduces the theorems that make up the electromagnetic field theory. Most of the basic field equations are given for easy reference. Since circuit theory is approximated from field theory, the transition from field to circuit is derived and highlighted in Chapter 3. This chapter emphasizes and illustrates the link between field and circuit theories. In Chapter 4, the finite-difference method for approximating first- and second-order derivatives is derived from Taylor's series. Chapter 5 introduces the Yee cell grid and includes the FDTD expressions for uniform and non-uniform formulations in both homogeneous and inhomogeneous media. Chapter 6 gives a simplified introduction to a SPICE-like analog circuit simulator. As the main theme of the book, general equations from Maxwell's equations for various types of current-contributing subsystems are discussed in Chapter 7. Chapter 8 gives details about the interface between FDTD and a lumped circuit simulator and general n-port system, described by its frequency domain S-parameters or port behavioral model. Chapter 9 demonstrates the applications of the circuit-field and multi-port co-simulation models in some high frequency circuits. Chapter 10 describes a generalized formulation for extending the FDTD analysis technique to nonlinear optical systems.

To order this book, contact: CRC Press LLC, 2000 NW Corporate Blvd., Boca Raton, FL 33431-9868 (800) 272-7737.

#### Distortion in RF Power Amplifiers

Joel Vuolevi and Timo Rahkonen
Artech House Inc.
252 pages; \$89, £62
ISBN: 1-58053-539-9

The goal of this book is to improve the conceptual understanding needed in the development of power amplifiers (PA) that offer sufficient linearity for wideband, spectrally efficient systems while still maintaining reasonably high efficiency. Since efficiency and linearity are mutually exclusive specifications in traditional power amplifier design, some type of linearization has to be employed. The main goal of linearization is to apply external linearization to a reasonably efficient but nonlinear PA so that the combination of the linearizer and PA satisfy the linearity specifications. This may seem simple enough, but in practice, several higher order effects seriously limit its effectiveness. The main emphasis of the book is on developing a detailed understanding of the physics underlying distortion mechanisms.

After a short introduction to the subject, Chapter 2 discusses certain theoretical aspects related to amplifier circuits and introduces a direct calculation method, based on the Volterra series, for deriving equations for the spectral components generated in nonlinear, bandwidth dependant circuits. Chapter 3 first discusses memory effects from the linearization point of view. Some of the most common linearization techniques are presented and then the chapter highlights the harmful memory effects in more detail. Chapter 4 discusses transistor/amplifier models and introduces problems related to PA modeling. Chapter 5 discusses the characterization of the Volterra model. The DC characterization is briefly covered for the sake of clarity, before shifting the focus on a new technique based on a set of small signal S-parameters measured over a range of bias voltages and temperatures. Chapter 6 presents a new simulation technique that offers insight into both amplitude and modulation frequency-dependant memory effects. Chapter 7 introduces three techniques for canceling memory effects: impedance optimization, envelop filtering and envelop injection.

To order this book, contact: Artech House Inc., 685 Canton St., Norwood, MA 02062 (781) 769-9750 ext. 4030; or 46 Gillingham St., London SW1V 1HH, UK +44 (0) 207 596-8750.