**2. History of the Smith chart**

Phillip H. Smith, inventor of the well known Smith chart, was born in Lexington, Massachusetts, on April 29, 1905 and died in Berkeley Heights, New Jersey on August 29, 1987, at the age of 82. In 1928, after graduating from Tufts College (now Tufts University) at the top of his class with B.S. degree in electrical communications, he was offered a job at Bell Telephone Laboratories. After 42 years in this company, Phillip Smith retired in 1970 and started a small company –Analog Instruments Company in New Providence, New Jersey – which initially sold navigational instruments for light aircraft. In his lifetime Smith held 21 U.S. patents and published over 35 technical papers on antennas and transmission lines.

In 1931, by modifying J. A. Fleming's 1911 telephone equations in an effort to simplify the solution of the transmission line problem, Smith developed his first graphical solution in the form of a rectangular chart. Even though the rectangular chart was very useful, Smith knew it had some limitations, namely the amount of data that could be accommodated. In 1936, Smith constructed a new type of transmission line chart that eliminated most of the limitations in his first diagram. The new chart was a special polar coordinate diagram which

network analyzers still have displays that imitate the Smith chart. Another example is the use of Smith charts in a lot of commercial software about antennas and microwave devices, to display the simulation results. The importance of the chart is enhanced by the global

The authors believe that the use of the Smith chart by undergraduate students and engineers is an important pedagogical tool, since many aspects of the voltage, current, impedance, Voltage Standing Wave Ratio (VSWR), referred commonly as SWR, reflection coefficient and matching design problems can be easily interpreted and well visualized using the Smith

 History and use of the Smith chart and its importance in the resolution of classical transmission line problems. Justification of its current use despite the present

 Construction of this chart from basic equations and concepts. Explanation of the main parameters that can be obtained from the chart. All these aspects will be supported by *MATLAB* scripts that display, step by step, the graphical procedure

 How to use the Smith chart. How to mark a normalized impedance and from then on to get several related parameters such as, the corresponding admittance, the VSWR, the reflection coefficient, the concept of travelling toward the generator or toward the load, the impedance at a given distance etc. Again, all these transmission line concepts will be explained through step by step procedures based

 Presentation of some examples that integrates all these transmission line concepts. One example is the single stub matching. The authors developed a *MATLAB* script that display, step by step, the graphical procedure that must be used to solve this problem. Others examples will be presented, because we believe they are important

Throughout the chapter, when explaining the step by step procedure, several displays will

Phillip H. Smith, inventor of the well known Smith chart, was born in Lexington, Massachusetts, on April 29, 1905 and died in Berkeley Heights, New Jersey on August 29, 1987, at the age of 82. In 1928, after graduating from Tufts College (now Tufts University) at the top of his class with B.S. degree in electrical communications, he was offered a job at Bell Telephone Laboratories. After 42 years in this company, Phillip Smith retired in 1970 and started a small company –Analog Instruments Company in New Providence, New Jersey – which initially sold navigational instruments for light aircraft. In his lifetime Smith held 21 U.S. patents and published over 35 technical papers on antennas and transmission lines. In 1931, by modifying J. A. Fleming's 1911 telephone equations in an effort to simplify the solution of the transmission line problem, Smith developed his first graphical solution in the form of a rectangular chart. Even though the rectangular chart was very useful, Smith knew it had some limitations, namely the amount of data that could be accommodated. In 1936, Smith constructed a new type of transmission line chart that eliminated most of the limitations in his first diagram. The new chart was a special polar coordinate diagram which

generalization of personal computers and powerful calculators.

information that is possible to obtain simultaneously.

The chapter will be organized as follows:

involved in the process.

on *MATLAB* scripts.

**2. History of the Smith chart** 

so students can learn on their own.

be shown to illustrate the use of the Smith chart.

chart.

could show all values of impedance and is essentially the Smith chart used today. Smith approached a number of technical magazines for publications of his transmission line diagram, however acceptance was slow. Finally, after two years Smith's article describing his chart was published in January 1939 issue of Electronics magazine. In a second article, published in the January 1944 issue of Electronics, Smith incorporated further improvements into his chart, including its usage as an impedance chart or an admittance chart, (Inan, 2005).

An interesting historical and theoretical background of the Smith chart can be found in the article written by Aleksandar Marinčić, (Marinčić, 1997).
