Contactless Characterization of Metals’ Thermal Expansion Coefficient by a Free-Space RF Measurement

In this communication, a novel method to characterize the thermal dilatation of metals using a contactless measurement of the frequency-dependent reflection coefficient of a resonator is introduced. This wireless technique allows extracting the thermal expansion coefficient of the material without the need of any calibration. Two antennas, a VNA, and a scatterer fabricated with the under-test material are required. All the measurements have been achieved using a climatic chamber with absorbers to control the scatterer's temperature. The measured values for thermal expansion coefficients are in good agreement with the values provided by the manufacturer which is confirmed by a sensibility study.