A measuring system for the accurate determination of material characteristics ε'r, μ'r tan δε, tan δμ in dielectrics and ferrites at microwave frequencies

摘要

Chemists and microwave engineers require instruments which permit the electromagnetic parameters of complex dielectric and permeable media to be continuously determined over wide frequency ranges in the VHF, UHF and SHF region with high accuracy. The manufacturers of ceramic insulants must know the electrical values of their products if these are to be used in special capacitors or as supports or components in high frequency systems. Measurement of the material characteristics is of vital importance in production testing as well as in the development of new materials. If insulating materials are used, whether they be ceramics, glass or plastic materials such as polystyrene, polythylene, Teflon, nylon etc., accurate knowledge of the values ε' and tan d is necessary for the compensation of electric discontinuities. Similarly the study of the behavior of ferrites in the microwave region is becoming increasingly important. For the chemical industry, the electrical characteristics are important not only for describing a product but also in basic investigations of solid and liquid materials where they may give valuable aid for distinguishing structure and arrangement of molecules when chemical analysis is insufficient.