Linsmith - A tool to generate Smith Charts

Wednesday, 14 July 2010 20:20

The Smith chart, invented by Phillip H. Smith (1905-1987), is a graphical aid or nomogram designed for electrical and electronics engineers specializing in radio frequency (RF) engineering to assist in solving problems with transmission lines and matching circuits. The Smith Chart is a graphical reflection coefficient system with normalized conformal mapping of impedance or admittance coordinates. A Smith Chart is still a very useful graphics method for getting a quick grasp of the effects of system design parameters on constant or varying frequency: it's a tool used in electrical/electronic engineering that shows how the complex impedance of a transmission line varies along its length, and simplifies the design of impedance matching networks to match the line to its load. You can enter either discrete components or transmission lines, see the results on screen and/or generate Postscript output. Component values can be changed numerically or using scrollbars. LinSmith is a Smith Charting program, mainly designed for educational use. As such, there is an emphasis on capabilities that improve the "showing the effect of" style of operation. Its main features are:

Definition of multiple load impedances (at different frequencies);
Addition of discrete (L, C, parallel and series LC, and transformer) and line components (open and closed stubs, line segments);
Connection in series and parallel;
A 'virtual' component switches from impedance to admittance to help explaining (or understanding) parallel components;
The chart works in real impedances (not normalized ones);
Direct view of the result on the screen;
Ability to generate publication quality Postscript output;
A 'log' file with textual results at each intermediate step;
Load and circuit configuration is stored separately, permitting several solutions without re-defining the other.

For more information about Linsmith, click here.