Next we’ll go through some examples of material fits and discuss how to modify the settings
in each case to obtain a better fit, as well as some fitting tips.
In the first example, we can see the fit does not match the data well.
The quality of the fit can be improved by increasing the number of coefficients from
4 to 10.
Next, suppose we want a better fit for the imaginary part of the permittivity.
Currently, we can see the fit to the real part is much better than the imaginary part.
This is simply because the real part is larger, so it contributes more to the RMS.
To improve the fit to the imaginary part, click Show advanced and increase the Imaginary
weight from 1 to 30.
This will put more emphasis on getting a good fit to the imaginary part, possibly at the
expense of a slightly worse fit to the real part.
The fit is now much closer to the imaginary data.
In this example, the fit initially looks fine, but a careful inspection shows some extra
peaks in the fit.
The experimental data contains some noise, and the fitting routine is attempting to fit
Assuming this feature is noise, and not the real material property, it is best not to
include this feature in the material fit.
This feature can be removed by reducing the number of coefficients from 15 to 4.