An overview of dielectric properties measuring techniques

Venkatesh, M.S. and Raghavan, G.S.V. 2005. An overview of dielectric properties measuring techniques. Canadian Biosystems Engineering/Le génie des biosystèmes au Canada 47: 7.15 7.30. With a need for the development of improved sensing devices for the control and automation of several agricultural, environmental, and food processes, there is an absolute need for better understanding of the dielectric properties of materials and techniques for measuring these properties. Microwave measurements and the dielectric properties of materials are finding increasing application as new electro-technology is adapted for use in the agriculture and food processing industries. The interest in dielectric properties of materials has historically been associated with the design of electrical equipment, where various dielectrics are used for insulating conductors and other components of electric equipment. Measurement of the bulk dielectric properties (dielectric constant, dielectric loss factor) is not an end unto itself. Rather, these properties are an intermediary vehicle for understanding, explaining, and empirically relating certain physico-chemical properties of the test material. Therefore, in this paper, an attempt is made to fully explore the existing knowledge of dielectric properties (complex permittivity), their role, and importance in the agri-food sector, and the concept of various measurement methodologies and their development. We have summarized the current status of research in this area with some notes on recent developments. An extensive review of the literature on measuring techniques and the comparison and potential application of dielectric properties is reported. Readers are advised to follow the appropriate literature cited for detailed and complete reference.