Back in the days when I had a lot more energy and a lot less sense, I wrote
the first edition of this book. I had just finished writing Microwave Mixers,
and friends kept asking me, “Well, are you going to write another one?”
Sales of Mixers were brisk, and the feedback from readers was
encouraging, so it was easy to answer, “Sure, why not?” After a year of
painful labor, Nonlinear Microwave Circuits was born.

The first edition of Nonlinear Microwave Circuits was published in
1988. It was well received and continued to sell well, even in a reprint
edition, for the next 13 years. Now, it is out of print, and properly so:
nonlinear circuit technology has advanced well beyond the material in the
first edition of that book. In 1988, general-purpose harmonic-balance
simulators had just become available, a workstation computer with an 8-
MHz processor and 12 megabytes of memory was the state of the art, cell
phones were the size of a shoebox, and the term microwave bipolar
transistor was an oxymoron. My point isn’t that we’ve come a long way;
you know that. My point is that the book was clearly due to be updated.

Nonlinear Microwave Circuits has been almost completely rewritten,
mainly to update its specific technical information. The general
organization of the book, with the first half presenting theory, and the
second design information, is unchanged. A couple of chapters, notably
Chapters 4 and 5, are essentially unchanged, for obvious reasons. Chapter
2, on device modeling, is almost twice as long as in the original edition,
and I easily could have made it longer. Chapter 3, on harmonic-balance
analysis, is likewise much longer. The last seven chapters, which are design
oriented, are completely new. In particular, design examples have been
modernized, so they show how modern circuit-analysis software can best
be exploited to produce first-class components.