1. Objectives and choice of measurement technique

As early as 1940, Von Hippel defined measurement techniques for homogeneous materials. These include guided techniques (rectangular waveguide, coaxial guide, open guide, microstrip line, triplate, etc.), cavities, open or closed resonators and free-space techniques. The latter have only been introduced in the last forty years, after equipment manufacturers had defined and produced highly stable microwave sources and highly sensitive, highly dynamic receivers. We could also add radar-equivalent surface measurement techniques conducted in anechoic chambers, and non-destructive...