Maximum Frequency Range Limit of Multi-Pole Debye Models of Human Body Tissues

The maximum frequency range limit is investigated for the dielectric property of human body tissues to be fitted with the Debye dispersion of up to three poles. The dielectric properties of the human body tissues compiled by Gabriel in the form of the 4-pole Cole-Cole models are reformulated into the Debye models by means of a weighted least squares method (W-LSM). It has been found that three-pole Debye function can model permittivity over the broad frequency range of five orders of magnitude, e.g., from 1 MHz to 100 GHz or from 100 kHz to 10 GHz within the root mean square error of several %.