Lumped Element Quadrature Hybrids

Quadrature hybrid circuits have wide application in radio frequency and microwave circuits and systems. Andrews (cofounder and technical director, Vectawave Technology) provides an introduction to the theory, design, and use of quadrature hybrids. After an overview of the various forms of quadrature hybrids and their uses, he describes basic theory, particularly with reference to lumped element forms. Issues of approximation and filter design are considered, followed by a chapter on circuit synthesis. Andrews then discusses how theoretical circuits are made in practice and concludes with an examination of special topics, including active circuits, unequal division and nonquadrature hybrids, power handling, graphical techniques for cascaded couplers, and a 50-550-MHz hybrid with sections of different topology. The reader is assumed to have a graduate-level knowledge of radio frequency and microwave circuits and theory. Annotation c2006 Book News, Inc., Portland, OR (booknews.com)