Once an answer is obtained through the graphical constructions described below, it is straightforward to convert between normalised impedance (or normalised admittance) and the corresponding unnormalized value by multiplying by the characteristic impedance (admittance). A Vector Network Analyzer and Smith Chart are used. with rectangular graphs, Smith Charts, polar grids, and antenna plots. This example matches a 2.4GHz chip antenna that could be used for ZigBee, Wi-Fi, or.
However, the antenna cannot be adjusted to 50 Ohm and. The return loss in the blue curve is better than -35 dB. The blue curve shows the attempt to simulate matching. The most commonly used normalization impedance is 50 ohms. The data cursor for the Smith Chart can display trace information as impedance. The red curves show the antenna not matched to 50 Ohm in the return loss diagram and in the Smith chart. A main goal of antennas impedance matching is compensating for capacitive or inductive reactance and transforming the impedance as. Normalised scaling allows the Smith chart to be used for problems involving any characteristic or system impedance which is represented by the center point of the chart. the observation point and the terminals of the device under study, whether that be an antenna or a transistor. It was't until about twenty years ago when I started researching the chart did I find the truth. In my younger days I was told that Carl Smith, of the consulting engineering firm Smith Electronics, Cleveland, Ohio, was the inventor. These are often known as the Z, Y and YZ Smith charts respectively. The Smith Chart was created by an RF engineer at R.C.A. 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.
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