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Over the last several decades, modern filter theory has been
significantly embellished by many contributors. In Zverev¡¯s [l]
words ¡°This search for useful theories has led to some of the
most elegant mathematics to be found in the practical arts.¡±
Excitement over this elegance is tainted by sophistication more
suited for the filter mathematician than the engineer whose
work is often less specialized. This book is directed to the
engineer and not the mathematician. We do so in full reverence
of the mathematicians who provided the tools to work with in
the trenches.For completeness, a review of which predates WW II.
more recent and some is of classic material is included, some
Of course most of the material is 1original. It is at times a strange
mixture, but always directed at the practical application of the
art to today¡¯s real-world problems.
Chapters 1 through 5 cover fundamental concepts. Although
this book emphasizes microwave filters, the first few chapters
cover lumped element concepts more heavily than distributed
elements. This is for two reasons. First, even at several
gigahertz, lumped elements are useful when size is important,
when stopband performance is critical and for MMIC processes.
Second, much of the lumped element theory, with suitable
modification, is applicable to distributed filter development.
Many engineers now at the peak of their careers began with
slide rules. Less than one floating point multiply per second is
performed to about three digits of precision using a slide rule.