Millimeter wave power density in aqueous biological samples

Power density distribution inside a water sample placed between two paralle l lossy dielectric plates (Polystyrene) was calculated using Fresnel equati ons for the frequency range of 42.25-53.57 GHz. Due to the multiple interna l reflections from the sample boundaries, the distribution of the power den sity within the thin sample is more uniform than that within a semi-infinit e medium. The power density in a sample depends on the thicknesses of the s ample and the adjacent dielectric plates. For the given frequency range the sample thickness optimal for power density uniformity varies between 0.28 and 0.33 mm. The front plate has a significant effect on the magnitude of t he power density within the sample but little effect on the power density d istribution. The thicker the rear plate, the greater is the non uniformity of the power density distribution within the sample. Based on the calculate d data, we determined the dimension of an exposure chamber providing the op timal power density distribution uniformity for mm-wave irradiation. (C) 20 01 Wiley-Liss, Inc.