Analytical Approach for Dielectric Property Measurements of Biological Tissues Based on Transmission Phase-shift Method

This paper presents an analytical approach for dielectric property measurements for biological tissues using a WR90 type X-band waveguide. The irregular shape of biological tissue as a specimen is overcome by placing it into a thin container to obtain a flat surface and then put it in inside of the waveguide. The dielectric property focused in this work is complex relative permittivity which is extracted from S-parameters and analyzed using transmission phase-shift (TPS) method. To verify the proposed method, several widely known materials are measured and compared with the Nicholson-Ross-Weir (NRW) method. In addition, it is demonstrated that the thickness of sample has a critical point to be considered in measuring a specimen with high relative permittivity.