Month: October 2024

Insertion Loss does not imply any specific conversion of energy to heat discussed an example of a lossless 100pF series capacitor in a 50Ω two port network context. This article presents measurement using a VNWA3E in a suitable fixture of a practical capacitor, an experiment that readers should be able to replicate.

This measurement set includes s21. NanoVNA does not natively correct load mismatch, so s21 measurements are tainted by that error. For that reason, the VNWA3E is used here.

The capacitor used is a 100pF silver mica capacitor, and it this configuration, we might expect Loss of the order of 0.001dB. It is a challenging measurement, and uncertainty prevents determining loss to that accuracy, but the objective is to show that InsertionLoss is almost entirely due to MismatchLoss in this example.

Above, marker frequency has been set so that capacitor reactance is ~100Ω. Continue reading Insertion Loss does not imply any specific conversion of energy to heat – measurement of the example

Firstly, for clarity let’s define Insertion Loss:

Insertion Loss is the ratio of power into a matched load (to mean that the load impedance is the complex conjugate of the Thevenin equivalent source impedance) to the power in the load with the subject network / device inserted.

Let’s calculate the InsertionLoss of a lossless 100pF series capacitor of reactance 100Ω @15.91MHz (\(\frac{1}{2 \pi 100e-12 \cdot 100}=15.91 \text{ MHz}\)).

We can do this by mental arithmetic: Continue reading Insertion Loss does not imply any specific conversion of energy to heat