Impedance Matching and Transmission Lines
A matching network optimizes the transfer of power from a source to a load by maximizing the power delivered to the load while meeting other performance specifications. For small-signal RF circuits, the power delivered to the load is maximized by conjugate-matching it to the source with a matching network. For power amplifiers, a matching network transforms the load impedance into Vmax/Imax, the ratio of the maximum rated voltage of the active device divided by the maximum current it can deliver. In any case, maximum power transfer is just one aspect of the design of an RF circuit. Others include noise performance, stability, and linearity. In any case, maximizing the power delivered to the load is just one aspect of the design of an RF circuit. As a result, optimizing a matching network in order to meet all the design specifications requires multiple iterations, which can become very laborious and tedious even with the aid of a circuit simulator. The use of the Smith Chart or a Mathca...
Circuit Sage Tools
MATHCAD/MATLAB
Simple Mathcad high-pass matching network routine:
Simple Mathcad routine to design an LC high-pass matching network given source and load impedances

Simple Mathcad high-pass matching network routine (.pdf):
.pdf file of Mathcad high-pass LC matching routine

Comprehensive Mathcad high-pass matching network routine:
Analysis of high-pass LC network, includes S-parameters plots and Smith Chart analysis

Comprehensive Mathcad high-pass matching network routine (.pdf):
.pdf file of comprehensive Mathcad high-pass LC matching routine

Simple Mathcad low-pass matching network routine:
Simple Mathcad routine to design an LC low-pass matching network given source and load impedances

Simple Mathcad low-pass matching network routine (.pdf):
.pdf file of Mathcad low-pass LC matching routine

Comprehensive Mathcad low-pass matching network routine:
Analysis of low-pass LC network, includes S-parameters plots and Smith Chart analysis

Mathcad Smith Chart impedance matching routine:
Mathcad routine for graphical impedance matching with a Smith Chart

Mathcad Smith Chart impedance matching routine (.pdf):
.pdf of Mathcad impedance matching routine

Mathcad Smith Chart impedance matching routines:
Collection of impedance matching networks

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Online Tools
MATHCAD/MATLAB
Interactive matching spreadsheet:
5th from the top, interactive Excel tool with circuit schematics

Smith Chart for Excel:
Plotting on a Smith Chart using Excel

Professor Reinhold Ludwig's MATLAB files:
From his book RF Circuit Design. Great stuff! Click on M-files on the left frame.

Mathcad routine for spiral inductors from UNC-Charlotte:
Mathcad routine for spiral inductors from UNC-Charlotte

SOFTWARE
Lance Lascari's Smith Chart program:
Matching network and filter synthesis

ZZMatch:
LC impedance matching design and analysis, for PC's. Includes Monte Carlo. $500, free to try for 20 days

RFMatch (FREE):
Freeware uses Smith Chart to do impedance matching. Very popular!

Wmatch:
From Michael Hutt, impedance matching over a range of frequencies using cascaded LC sections

LINC2 suite:
$500, differential filter design and many other features

RF Netwok Designer:
$119, design many types of networks

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Online Articles
Professor Reinhold Ludwig's course notes at WPI:
Very good reference for transmission lines and matching, 28 lectures in .pdf with plots and equations

Motorola application note on RF power matching:
Practical article on matching for power amplifiers

Broadband HF antenna matching :
By William Sabin, using ARRL Radio Designer software

Philip H. Smith: A Biography:
Very interesting biography of the Smith Chart creator

SS-Mag's Smith Chart resources page:
Software and links to other pages about the Smith Chart

How to build a Smith Chart with Mathcad:
Using Mathcad to draw Smith Charts and solve matching problems

Maxim's tutorial:
Tutorial on RF impedance matching, presents equations used to build the Smith Chart

Impedance matching class notes:
Various note sets on impedance matching. Very nice.

Modelling skin effects in SPICE:
Simulation technique to model skin effect in SPICE, verified with experiment

Time-domain model of dispersion transmission line thesis:
Master's thesis uisng APLAC software

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Books
RF Circuit Design, Second Edition by Chris Boswick:
Very good RF resource. From a reviewer: "...An excellent, concise, introduction to RF circuit design. The emphasis is on the practical aspects relating to RF circuit design..."

Microwave Transistor Amplifiers: Analysis and Design by Guillermo Gonzalez:
Essential for RF amplifier design

Electromagnetic Waves and Antennas by Sophocles J. Orfanidis (FREE!):
FREE online book from Rutgers, chapters 10, 12, and 13 with great information on Smith Chart, impedance matching, and transmission lines

Digital Transmission Lines: Computer Modelling and Analysis with CD-ROM by Kenneth Granzow:
from description: "...The text's most significant feature is its method of simulating crosstalk between closely spaced traces on a circuit board and providing design tools for its control. The author explains methods that he has successfully used to simulate multi-wire transmission line signal propagation; provides explanations that enhance students' understanding of propagation and crosstalk; and uses mathematical algorithms for their numerical evaluation..."

Signal Integrity - Simplified by Eric Bogatin:
Very good reviews

Electromagnetics Explained by Ron Schmitt:
from a review:"...Many engineers face a large gap between the elegant simplicity of Maxwell's equations and the practical aspects of electromagnetic issues. Electromagnetics Explained by Ron Schmitt bridges that chasm..."

High Speed Digital Design: A Handbook of Black Magic by Howard Johnson:
from description: "...this comprehensive volume will help engineers who work with digital systems, shorten their product development cycles, and fix their latest high-speed design problems...."

High Speed Signal Propagation: Advanced Black Magic by Howard Johnson:
very good reviews

Transmission Lines and Communication Networks by Richard Matick:
Re-issue of 1969 classic

Foundations for Microwave Engineering by Robert Collin:
Re-issue of 1992 book that is highly regarded by many

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Henry Nguyen

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