Optenni Lab — Visualizing impedance trace

The impedance trace feature visualizes how the components of a matching circuit transform the originial impedance to the input impedance at one frequency. The visualization shows how series components rotate the impedance along the constant resistance circles of the Smith chart and parallel components rotate the admittance along the constant conductance circles.

Consider the pictures below showing a three-component matching circuit, the S-parameters through the matching circuit and the corresponding Smith chart plot showing the original impedance, impedance through the matching circuit, impedance trace and also the admittance chart.

 

trace_circuit

 

trace_mainplot_small

 

trace_smith

 

The Smith chart plot shows at the selected frequency (1.922 GHz) how the parallel (red lines) and series (black lines) components move the impedance from the original impedance curve (violet curve, circle marker) to the input impedance (blue curve, cross marker).

 

The impedance trace feature is very instructive as it shows how the different components affect the impedance. You can gain more insight into the operation of the matching circuit by changing the frequency where the trace is calculated (by dragging the vertical dashed line on the S parameter plot) or by tuning the component values (by moving sliders in a separate tuning window). The effect of both operations is shown in real time on the Smith chart and S parameter plots. Thus, the impedance trace visualization helps to understand the operation of the matching circuit and is also a great tool for teaching.