Complex relative permittivity is [defined](https://en.wikipedia.org/wiki/Relative_permittivity#Definition) as

$$\epsilon\_r = \frac{\epsilon(\omega)}{\epsilon\_0}=\epsilon\_r^{\prime}(\omega) + i\epsilon\_r^{\prime\prime}(\omega) = \epsilon\_r^{\prime}(\omega) + \frac{i\sigma}{\omega\epsilon\_0}$$

Measuring the real **static** permittivity, $\epsilon\_r(\omega=0)$, [can be done](https://en.wikipedia.org/wiki/Relative_permittivity#Measurement) by a plate capacitor, $\epsilon\_r=\frac{C\_x}{C\_0}$. But how can I get a chart like [this one](https://commons.wikimedia.org/wiki/File:Dielectric_responses.svg)?

[![enter image description here](https://i.stack.imgur.com/okZWO.png)](https://i.stack.imgur.com/okZWO.png)

**EDIT:** A practical question about the same thing was [posted on electronics.SE](https://electronics.stackexchange.com/questions/210414/how-to-measure-complex-permittivity-of-a-capacitor).