## The Book End

Green's Function, Finite Elements and Microwave Planar Circuits

J. Helszajn

John Wiley & Sons Ltd.
259 pages; \$65

Applying Green's function to planar microwave circuits is well accepted as a fundamental tool in electromagnetic analysis. This book presents comprehensive and detailed methods for describing practical microwave circuits numerically using various modern mathematical techniques. Planar resonators, gyromagnetic circuits and junction isolators are some examples analyzed using Green's function. In addition, the text provides a detailed explanation of finite element method (FEM) techniques used for determining the solution of planar isotropic and gyromagnetic circuits.

The book begins with descriptions of planar circuits, and governing differential equations and associated boundary conditions. The Green's function and its application to regular microwave circuits are described, including its use with rectangular patch and ring geometry. Green's description of open-circuit parameters in regular circuits is discussed with examples of one- and two-port rectangular patches.

Interpolation using finite elements is explained with an introduction to simplex polynomials and a detailed description of the triangular and rectangular elements used in the FEM. Finite element calculations are described with their associated matrix evaluations. FEM techniques are then employed to analyze a cloverleaf resonator with three- and four-fold symmetry. The eigenvalues of planar resonators with an electric rather than magnetic wall are described, as well as resonators with a mix of both magnetic and electric boundaries. A three-port junction circulator is used as an example of Green's function analysis using the FEM. Other subjects covered include the contour integral method; network parameters of reciprocal planar and N-port nonreciprocal circuits; energy functionals of gyromagnetic waveguides; and matrices, quadratic forms and energy functions.

This book offers a highly specialized treatment of a fundamental microwave analysis tool. The book was written specifically for engineers and post-graduate researchers engaged in the analysis and development of planar circuits.

To order this book, contact: John Wiley & Sons Ltd., Baffins Lane, Chichester, West Sussex PO19 1UD, UK (01243) 770463.

FINCAD: Fin-line Analysis and Synthesis for Millimeter-wave Applications

S. Raghu Kumar, Anita Sarraf
and R. Sathyavageeswaran

Artech House Inc.
48 pages plus software; \$300, £250

The fin line is one of the most important transmission media for mm-wave ICs, offering several distinct advantages over other types of transmission media such as microstrip. Basically, the fin line is a slot line inserted in the E-plane of a waveguide perpendicular to the broadside of the waveguide. The structure supports a hybrid transmission mode with the conducting pattern printed on either side of the dielectric substrate using MIC techniques. The advantages are low loss, waveguide compatibility and less stringent dimensional tolerances. Fin lines have been used succesfully from 30 to 170 GHz.

The software and associated operating manual enable microwave and mm-wave design engineers to analyze and synthesize a variety of fin-line structures. The software generates complete dispersion and propagation details, including normalized guide wavelength and characteristic impedance. The program also synthesizes any fin-line configuration for a given set of propagation characteristics by utilizing the spectral domain technique.

The fin-line software package is equipped with a built-in root-finding routine and a powerful graphics tool that gives users the freedom to zoom in on visuals. The program is user friendly with on-screen instructions and sophisticated on-line help.

The associated instruction manual provides an introduction to fin lines and a description of the software program capabilities. The manual details the various functions the software performs, including calculating dispersion characteristics, and analyzing and synthesizing a given fin-line structure. Methods of manipulating the graphics display are described and the various utility functions are explained.

Primarily, the software is a tool for fin-line component designers at microwave and mm-wave frequencies. The software provides an easy and efficient method of analyzing and synthesizing fin-line structures.

To order this book, contact: Artech House Inc., 685 Canton St., Norwood, MA 02062 (617) 769-9750, ext. 4002; or Portland House, Stag Place, London SW1E 5XA, UK +44 (0)171 973 8077.