ABSTRACT
This chapter focuses on biological materials. Complex permittivity measurements of biological materials are of particular importance since interest exists to understand the interaction of electromagnetic energy with biological tissues up to millimeter wave frequencies. The therapeutic, dosimetric, or other applications require knowledge of dielectric properties of the tissues. From the electromagnetic engineering point of view, studying the bulk dielectric properties remains the most direct way of characterizing any substance. From a macroscopic view, in electromagnetic problems dielectric properties of materials are quantified by their bulk complex permittivity. The electrical properties of a material exposed to electromagnetic fields are in general frequency dependent. A material, which demonstrates significant permittivity changes in the frequency range of interest is referred to as a dispersive one in that range. More studies are needed to characterize the electromagnetic field interactions with biological systems in millimeter wave frequencies, by characterization of various tissues at these frequencies.
