WAVE-GUIDE CAVITY PERTURBATION METHOD FOR MEASURING COMPLEX PERMITTIVITY OF WATER

An accurate method of measuring the complex permittivity of high-loss liquids like water by use of a waveguide perturbation technique is presented. The sample taken in a thin capillary tube of low-loss material is inserted in the S-band waveguide cavity. Resonance frequency and frequency shift are measured with a H.P. network analyzer and the complex permittivity is calculated. This method is particularly useful in the case of high-loss liquids. Another advantage of this method is that only a very small quantity of liquid is needed for the study.