Extra Story 2: How to find the center of power circle and efficiency circle with ADS load (source) pull
Taking source impedance matching as an example, the circuit diagram is as follows: Set
the relevant parameters according to the requirements, first of all, the basic setting parameters:
the following parameters are related to the display on the circle diagram, s11_rho is the scanning radius, and s11_center is the scanning center, and these two parameters use default values here. Z0 is the characteristic impedance, which is mainly used for the normalization of the circular graph, and it can be set arbitrarily. Here, it is set to 10 for easy calculation: click the simulation button to get the result graph: the center of the
efficiency
circle or the power circle is not found at this time, and it can be inferred that the center of the efficiency circle is in the third quadrant (refer to the trend of the circular graph displayed), so you can modify the scanning center to the following value: Run the simulation again: you can see that the center of the circle is still not found, but it is clearer than before, and fine-tune the center of the scanning circle
again
:
It can be seen from the figure above that the center of the circle has almost been found, but you can move a little towards the negative semi-axis of the imaginary axis and modify it to the following value: From the figure above, you can find the center of the power
and efficiency circle, where the center of the power circle is marked by m2, and the suitable source impedance is Z0*(0.210-J0.539), and the characteristic impedance Z0=10 can be calculated. The result of the source pull is 2.1-j5.39 ohms.