The coordinate system of the Smith Chart is a plot of complex numbers representing
the reflection coefficient. The reflection coefficient is basically a ratio, and thus has no units.
You can read reactance and resistance from the arcs and circles that are drawn as part of the Smith Chart.
The Smith Chart itself is plotted in the complex plane, the coordinate grid is not typically shown on most
Smith Charts but could be either standard issue cartesian coordinates or polar coordinates as fully
described in Jeff's tutorial. That is the whole point of his tutorial. He makes it very clear what and how
stuff is plotted on the Smith Chart. Most Smith Chart tutorials just give the mechanics of how to use it
with a very brief mention that it involves the reflection coefficient.
Here is a brief section of the part where he describes what is being plotted:
Its impedance mismatch (as represented with its Reflection Coefficient) from our target impedance of Zo = 50 ohms calculates to be:
¦£ = 0.8 + j0.4
And we can plot its position (using Cartesian coordinates) on the complex plane:
The only thing I might add to the tutorial in this regard would be to state that the reflection coefficient has no units.
Other than that, any suggestions out there on how to improve this aspect of the tutorial?
It is a key concept, and quite confusing.
Jerry, KE7ER
On Sun, Oct 20, 2019 at 01:46 AM, Oristo wrote:
a quick skim read indicated no reference to what the x & y axes are,
which is something I have noticed with several descriptions of the Smith
Chart.
Sad, because Smith chart simply plots S11 reactance vs resistance.
