Sample Thickness Does Not Affect Split-Cylinder Resonator Measurements (40 GHz, PP)

Measurement Results

Key Point!

• When material properties are the same, thin and thick samples produce the same measurement results.

We are sometimes asked whether dielectric measurements change when samples of the same material have substantially different thicknesses. With the EM labs split-cylinder resonator, thin and thick samples produce the same result as long as the material properties are the same.

To demonstrate this, ten specimens were cut from a large 20 micrometer polypropylene film. Results from individual specimens were compared with results obtained by stacking them. No significant difference was observed between measurements at approximately 20 and 200 micrometers. If samples described as the same material give different results at different thicknesses, their material properties are likely not actually identical.