Experimental Characterization of Biological Tissue Dielectric Properties through THz Time-Domain Spectroscopy

TL;DR

This work provides one of the first extended-frequency datasets of biological tissue dielectric properties, supporting realistic channel modeling for the design and development of intra-body nanosensor networks in the THz band.

Abstract

Terahertz (THz) radiation provides a non-ionizing, highly sensitive probe of the dielectric properties of biological tissues. In this study, we present a comprehensive experimental characterization of dielectric properties using pork skin tissue, a widely used surrogate for human tissue, as a biological sample. Measurements are conducted employing THz time-domain spectroscopy in the 0.1-11 THz frequency range with photoconductive antennas for both signal generation and detection. Frequency-dependent refractive indices, absorption, and complex permittivity are extracted from transmitted time-domain signals. Our results confirm strong absorption and low transmittance at low THz frequencies due to water content, while highlighting frequency-dependent dispersion and narrowband transmission features at higher frequencies. This work provides one of the first extended-frequency datasets of biological tissue dielectric properties, supporting realistic channel modeling for the design and development of intra-body nanosensor networks in the THz band.

Figures (6)

• Figure 1: Figurative diagram of the THz time-domain spectroscopy system for tissue analysis. The THz pulse, generated and detected using PCAs, interacts with the tissue, and the response is processed to reconstruct the waveform.
• Figure 2: Stages of the proposed framework. The experiment comprises three main steps: signal generation, tissue interaction, and signal detection.
• Figure 3: Experiment setup overview. a) The instrumentation was covered with plastic to avoid contamination. b) Skin samples were hooked up to wooden sticks. c) Skin samples in the instrument chamber to perform the experiments,
• Figure 4: Measured transmittance in the [0--12] THz range. A zoomed figure shows the behavior near the incident radiation frequency.
• Figure 5: a) Absorption coefficient of pig skin in the 0--12 THz range. b) refractive index of pig skin in the 0--12 THz range. A zoomed figure shows the behavior in a closed range around the frequency of the incident radiation.