Electromagnetic Property Characterization of Biological Tissues at D-Band

Abstract

This paper presents, for the first time, measured complex dielectric and magnetic properties of liquid and solid biological tissues taken from human arteries in the frequency range 110-170 GHz. The complex permittivity and permeability are extracted from scattering parameters of a waveguide capsule loaded with biological tissue. The estimation of the dielectric properties was done by the Nicholson-Ross-Weir conversion process. A D-band waveguide setup for measuring with temperature stabilization at 37 °C was developed and is described herein. Results show large differences between dielectric properties of blood (10.7 + j2.9), adipose tissue (2.5 + j0.3), calcified tissue (3.2 + j0.84), and fibrous tissue (8.8 + j3.3). While calcified tissues and adipose tissues show relative permeability higher than 1 (1.8 - 1.4 + j0.2), fibrous tissues show μ r of 1 + j0.4 and blood proves to be diamagnetic with 0.7 + j0.5. The measured blood refractive index follows the frequency trend of the Cole-Cole model extrapolated data of previously measured blood at lower frequencies.