Ricerc@Sapienza

This chapter deals with the vector network analyzer systems used for the study of the electromagnetic properties of materials. The focus of the chapter is not the device itself, about which plenty of literature is available, but its application in materials characterization at the microwave and millimeter wave levels. Some interesting measurement techniques are presented and discussed in detail with the help of numerous experimental results. Moreover, the measurement criteria are commented on as a function of the materials under test.

Dielectric permittivity-based measurement techniques are establishing themselves as attractive solutions for assessing the moisture content of historic masonry materials. The relative simplicity of the measurement principle and the inherent adaptability to diverse operating conditions are two of the most notable features of these techniques. In spite of these specific advantages, however, there are still some aspects that hinder the widespread use of permittivity-based moisture content measurement systems, and make their standardization difficult.