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.