Modified Infinite Sample Method for Routine Permittivity Measurements at Microwave Frequencies

A modified infinite sample method for routine permittivity measurements of granular or powder as well as liquid materials is described. The method permits continuous monitoring of the temperature, moisture content, and density of the test sample. Analytical and graphical solutions, which lead to the material permittivity from experimental data and measurement uncertainty, are presented. The method is particularly valuable when a large number of samples must be tested as a function of temperature, moisture content, and density, or when a continuous monitoring of the permittivity is required during irradiation by microwave power.