Someone might be able to explain it in a simpler way, but you won't be able to use it per se. I'm not trying to scare you away from the possibility of comprehending this chart, I'm just giving you some perspective on what you're dealing with. Without this base knowledge you can't really understand the smith chart, at least in an EE sense. How about some EE stuff: do you know what resistances, impedances, reactances, or admittances are? Do you know what a transmission line is? How familiar are you with waves and reflection? How well do you understand complex (imaginary) numbers? Do you know what it means to express them in rectangular and polar form? They are called complex numbers and they have properties that make them very convenient for engineering. The i and j just tell you this is the second coordinate, so instead write it as (A,B). Įdit Forgot to add that when he gives you it will typically look like or. Each half-rotation is and you can confidently tell your boyfriend you know the input impedance for any load impedance on a transmission line with characteristic. When you rotate you go clockwise or towards the generator. We called it L above and most of the time it is a fraction multiplied by this symbol lambda.

Now you need to know how far you want to go. Next grab yourself a ( (drafting)#Construction) and put the spike end at the center of the Smith Chart and draw a circle passing through your point. Draw that point on your Smith Chart ( print one out btw). We'll call that (normalized load impedance). This is really easy, just divide each coordinate of by. We need to move into our Smith Chart coordinate system by normalizing the values. Next, you need to get a coordinate, we'll call it (load impedance). This is usually called (characteristic impedance). Here are the steps:įirst you need to know what your reference value is. In this case we are going to move a coordinate by a distance L. The curve B = 1 is the curve that ends up pointing straight up, B = -1 is the one pointing straight down.Ī Smith Chart has a ton of uses, but we'll just go with the simplest and if you get that we can talk about it in more detail. B varies from 0 (the line from the left center to right center, cutting the circle in half) to infinity (the right point). There are positive arcs (starting from the right center they curve up to the top) and negative arcs (curving towards the bottom). The second coordinate is the arcs of doom (we'll call B). A = 1 is the circle with left edge at the center and right edge at the right. A varies from 0 (the entire circle) to infinity (the point on the right).

The first coordinate (we'll call A) are circles with the right edge passing through the right center point. It's a coordinate system just like you would find on graph paper, except now it's curved.

Smith chart