Measurements of Complex Dielectric Constant of Human Sera and Erythrocytes

A method for measuring the complex permittivity of biological liquids at microwave frequencies is presented. The calibration needs three reference materials; this method allows measurements to be made very quickly, using only very small amounts of material. Measurements were made on human erythrocytes, obtaining their inner conductivity using Fricke's equation, and on human sera of normal and sick individuals. Using an optimization technique, some parameters related to the water bound to the serum proteins were identified, showing differences possibly related to the presence of certain diseases.