Layered Dielectric Characterization of Human Skin in the Sub-Terahertz and Terahertz Frequency Ranges

TL;DR

This paper develops a detailed dielectric model of human skin in the sub-terahertz and terahertz ranges, enabling improved non-invasive imaging and diagnostics by accurately predicting tissue permittivity based on cellular composition.

Contribution

It introduces a comprehensive dielectric model combining multi-Debye relaxation and effective medium theories for human skin and cells across sub-THz and THz frequencies.

Findings

Model accurately predicts frequency-dependent permittivity of skin layers.

Incorporates cellular water, proteins, lipids, and ions for realistic tissue characterization.

Provides a foundation for designing advanced THz diagnostic tools.

Abstract

Sub-terahertz (sub-THz) and terahertz (THz) radiation offer unique opportunities for non-invasive diagnostics and imaging due to their sensitivity to water content and molecular dynamics in biological tissues. In this work, a comprehensive dielectric model of human skin and its cellular constituents is developed across these frequency ranges. The model combines multi-Debye relaxation theory with effective medium formulations to account for intracellular water dynamics and macromolecular relaxation processes. Key cellular parameters, including water content, protein and lipid fractions, and ionic conductivity, are integrated from experimentally validated sources. The proposed framework enables realistic predictions of frequency-dependent permittivity for different skin layers and cell types, providing a physically interpretable description of sub-THz and THz tissue interactions. This approach establishes a foundation for the design and optimization of next-generation diagnostic and imaging techniques operating in these frequency bands.