Accurate measurements of complex permittivity of liquid based on a TM/sub 010/ mode cylindrical cavity method

Accurate values of complex permittivity of two kinds of liquids have been measured by using a TM/sub 010/ mode cylindrical cavity method. The conventional cavity perturbation method is improved on the basis of the rigorous analysis by the Ritz-Galerkin method, where the effects of sample insertion holes, a dielectric tube, and air-gap between a dielectric tube and sample insertion holes are taken into account. Actually, the values of the complex permittivity of ethanol and milk were measured as functions of the weight percentage of ethanol to water and the milk fat percentage, respectively. These measured results are useful to estimate the content percentage.