![]() The only thing you need to do is enter S11 or to-be-matched impe dance and you’ll get the approximate result by following all steps. However, if you are vague to the Smith chart then you should STOP here and go back to learn the Smith Chart Basics first. Only after finishing reading the sequence and knowing all basics, you then can use this skill effectively.īased on the values of r, g, x, and b, we can roughly categorize the impedance into 4 different types:įig. 1 Four types of impedance in the Smith chart. Theoretically all these 4 types of impedance can be perfectly matched into 50Ω by using only 2 lumped elements, inductors and capacitors, if not considering the limited amount of component values we are able to get as well as their tolerances. The very basic RULES of impedance matching are: However, I would not suggest to use lumped elements for impedance matching over 5 GHz because it’s hard to find small enough elements, value and size, and the path length will play a main role for the matching process. Add a lossless element, capacitor or inductor, to get the real part of either impedance or admittance to be 1.Add the second lossless element to tune out the remaining imaginary part, reactance or susceptance, so the resultant impedance or admittance is a real number 1 (\(z=1 j0\) or \(y=1 j0\)).Matching Type #1 impedance: r ≥ 1, x any value. Type #1 impedance is located within the area of \(r=1\) circle. The process to match a Type #1 impedance into 50Ω:ġ. If return loss \(S_\) or reflection coefficient \(Γ\) is given by datasheets, then refer to this article Smith Charts-Basics, Parameters, Equations, and Plots to learn how to convert the number to impedance.Ģ. If the impedance is \(Z=R jX\), then the normalized impedance is \(z=Z/50=r jx\).ģ. Locate the impedance \(z=r jx\) in the Smith chart, point X.įig. 8 Type #2 impedance in the Smith chartĪs showed in Fig. 8, we can simultaneously read the impedance \(z\) and admittance \(y\) of point X:įollow the first basic rule of impedance matching, add a lossless element, capacitor or inductor, to get the real part of either impedance or admittance to be 1. Maxwell published his famous equations governing all electrical and electronic phenomenon (with some quantum mechanics in some cases) in 1873.The only options to satisfy this first rule is add a capacitor, Option #1, or an inductor, Option #2, in series to move the impedance \(z\) along the \(r=0.4\) circle until meeting \(g=1\) circle at points O1-S1
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