# smith chart

The Smith chart is plotted on the complex reflection coefficient plane in two dimensions and is scaled in normalised impedance (the most common), normalised admittance or both, using different colours to distinguish between them. These are often known as the Z, Y and YZ Smith charts respectively.[7] Normalised scaling allows the Smith chart to be used for problems involving any characteristic impedance or system impedance, although by far the most commonly used is 50 ohms. With relatively simple graphical construction it is straighforward to convert between normalised impedance (or normalised admittance) and the corresponding complex voltage reflection coefficient.

The Smith chart has circumferential scaling in wavelengths and degrees. The wavelengths scale is used in distributed component problems and represents the distance measured along the transmission line connected between the generator or source and the load to the point under consideration. The degrees scale represents the angle of the voltage reflection coefficient at that point. The Smith chart may also be used for lumped element matching and analysis problems.

Use of the Smith chart and the interpretation of the results obtained using it requires a good understanding of AC circuit theory and transmission line theory, both of which are pre-requisites for RF engineers.

As impedances and admittances change with frequency, problems using the Smith chart can only be solved manually using one frequency at a time, the result being represented by a point. This is often adequate for narrow band applications (typically up to about 5% to 10% bandwidth) but for wider bandwidths it is usually necessary to apply Smith chart techniques at more than one frequency across the operating frequency band. Provided the frequencies are sufficiently close, the resulting Smith chart points may be joined by straight lines to create a locus.

**Online smith chart**

This graphics-intensive program is a valuable transmission-line calculator for both advanced and beginning users. Based on the venerable and highly intuitive Smith chart, it provides high-accuracy computations without recourse to paper, compass or straightedge.

Here are the highlights of this program:

Uses the full graphics capabilities of the Windows ® operating system for network entry, analysis controls and displayed results. Most notable are the extensive zooming and panning capabilities of the chart display.

Allows real-time interaction with the analysis computation in a seamless, intuitive manner with changes in component values and operating frequency immediately displayed.

Analyzes networks composed of transmission lines, stubs and lumped components (L’s, C’s and R’s) in both series-connected and shunt-connected configurations.

Program setups, including network configurations, are stored offline for immediate retrieval in an open, text-based format.

Analysis results are displayed over impedance or admittance coordinates or over readily-apprehended overlays of both.

Numeric readout of any point on the chart in terms of impedance, admittance, complex reflection coefficient, VSWR and return loss is available at any time with a mouse click.

In addition to displaying the results of sweeping the operating frequency, those results are also available in tabular form for input to other analysis and synthesis programs.

As an aid to designing impedance-matching networks, a constant-VSWR circle and constant-Q curves may be displayed.

visit http://www.tonnesoftware.com/supersmith.html for free download

**additional links**

Smith chart – The Smith chart, invented by Phillip H. Smith (1905-1987), [1] [2] is a graphical aid or nomogram designed for electrical and electronics engineers specializing … The Smith chart is plotted on the complex reflection coefficient plane in two dimensions and is scaled in normalised impedance (the most common), normalised … Normalised scaling allows the Smith chart to be used for problems involving any characteristic impedance or system impedance, although by far the most commonly … Overview – Mathematical basis – Using the Smith chart to solve …

http://en.wikipedia.org/wiki/Smith_chart

A Collection of Smith Chart Resources This page provides a collection of some of the BEST Smith Chart, s-parameter, impedance, admittance, matching circuit and related RF or microwave … The Smith Chart was originally created many years ago as an RF engineering aid by Phillip Smith of RCA. Actually, Smith may not have been the first … This article explains RF fundamentals such as transmission lines and the Smith chart, leading to the concepts of reflection, transmission and S-parameters. All …

http://sss-mag.com/smith.html

Agilent | Smith Chart This interactive animation introduces the Smith Chart and demonstrates how it can be used to relate a transmission line reflection coefficient to the load impedance., If we know the reflection coefficient, we can determine the characteristic impedance of the load by using a Smith Chart. The … The Smith Chart can help us translate the reflection coefficient into impedance. First, measure the reflection coefficient with a network analyzer (or invent …

http://education.tm.agilent.com/index.cgi?CONTENT_ID=5

Impedance Matching and the Smith Chart: The Fundamentals – Maxim Abstract: Tutorial on RF impedance matching using the Smith chart. Examples are shown plotting reflection coefficients, impedances and admittances. A … A Smith chart is a circular plot with a lot of interlaced circles on it. When used correctly, matching impedances, with apparent complicated structures, can … A Smith chart is developed by examining the load where the impedance must be matched. Instead of considering its impedance directly, you …

http://www.maxim-ic.com/appnotes.cfm/an_pk/742/

How does a Smith chart work? – 2006-03-07 02:00:00 EST | Test … The Smith chart appeared in 1939 as a graph-based method of simplifying the complex math (that is, calculations involving variables of the form x + jy … Although calculators and computers can now make short work of the problems the Smith chart was designed to solve, the Smith chart, like … Although the Smith chart can look imposing, it’s nothing more than a special type of 2-D graph, much as polar and semilog and log-log scales constitute …

http://www.tmworld.com/…/323044-How_does_a_Smith_chart_work_.php

Smith Chart Basics – Microwave Encyclopedia – Microwaves101.com We’ve got our own Smith chart tutorial here, thanks to a fan from Florida, Mike Weinstein, who really knows this subject, and is a fine writer too. If … The Smith chart was developed by Philip Smith at Bell Telephone’s Radio Research Lab during the 1930s. Be sure to check out our entry on Philip Smith in … The Smith chart contains almost all possible impedances, real or imaginary, within one circle. All imaginary impedances from – infinity to + infinity …

http://www.microwaves101.com/encyclopedia/Smithchart.cfm

Smith Chart Display a sequence of normalized impedance, admittance or reflection coefficient in a circle of unity radius commonly known as a Smith Chart …

http://www.eecircle.com/applets/006/JSmith.html

Smith Chart Smith Chart. The Smith chart is one of the most useful graphical tools for high. frequency circuit applications. The chart provides a clever way to … From a mathematical point of view, the Smith chart is a 4-D. representation of all possible complex impedances with respect to … is also the domain of the Smith chart. In the case of a general lossy line, the. reflection. coefficient. might. have. magnitude larger than one, due to the. complex …

http://www.amanogawa.com/archive/docs/G-tutorial.pdf

The Smith Chart The SMITH chart is a graphical calculator that allows the relatively complicated mathematical calculations, which use complex algebra and numbers, to be replaced with … The SMITH chart lets us relate the complex dimensionless number gamma at any point P along the line, to the normalised load impedance zL = ZL/Zo which causes the … In this way, we can get away with a single SMITH chart calibration for all possible line characteristic impedances. As …

http://www.antennex.com/preview/Folder03/Oct4/smith.htm

**Related**

COMMENTUncategorizedThe Smith Chart, invented by Phillip H. Smith (1905-1987).

The Smith Chart can be used to represent many parameters including impedances, admittances, reflection coefficients, S_{nn}, scattering parameters, noise figure circles, constant gain contours and regions for unconditional stability.The Smith Chart is most frequently used at or within the unity radius region. However, the remainder is still mathematically relevant, being used, for example, in oscillator design and stability analysis.

The Smith Chart 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. Use of the Smith Chart utility has grown steadily over the years and it is still widely used today, not only as a problem solving aid, but as a graphical demonstrator of how many RF parameters behave at one or more frequencies, an alternative to using tabular information. The Smith Chart can be used to represent many parameters including impedances, admittances, reflection coefficients, scattering parameters, noise figure circles, constant gain contours and regions for unconditional stability. The Smith Chart is most frequently used at or within the unity radius region. However, the remainder is still mathematically relevant, being used, for example, in oscillator design and stability analysis.