RF heating and power absorption in heterogeneous child models under Wi-Fi exposure

Abstract

The proliferation of wireless technologies, particularly Wi-Fi systems and mobile networks has significantly increased anthropogenic electromagnetic (EM) pollution. This expansion increasingly disrupts the natural EM background, raising critical concerns regarding the long-term biological consequences of continuous exposure to high-frequency fields. Because the interaction between radiofrequency (RF) radiation and biological structures is highly complex and frequency-dependent, accurately quantifying this interaction has become a fundamental challenge in biomedical engineering and public health safety.

This study presents a comprehensive numerical assessment of the thermal effects induced by EM fields at 2.1 GHz, 5 GHz, and 6 GHz. The primary focus is on a child anatomical model, as children are hypothesized to be more sensitive to EM fields due to their higher tissue hydration levels and developing physiological systems compared to adults. Utilizing the FDTDLab software suite, which implements the finite-difference time-domain (FDTD) method, we simulated EM wave propagation and subsequent dielectric heating within heterogeneous anatomical models.

The exposure scenarios were derived from real-environment field measurements; in areas where elevated field strengths were observed, spectral analysis identified the dominant frequencies. While the 2.1 GHz frequency served as the core of the urban exposure simulation, the inclusion of 5 GHz and 6 GHz frequencies reflects the modern integration of Wi-Fi 6 and 6E standards. Energy deposition was quantified using the whole-body average Specific Absorption Rate (SAR), as well as localized SAR averaged over 1g and 10g tissue masses. In parallel, thermal modeling was performed to estimate both localized temperature hotspots and systemic thermal stress. Finally, the resulting numerical data were evaluated against international safety guidelines established by the IEEE and ICNIRP. Ultimately, this study provides essential insights into EM safety, with a specific focus on vulnerable younger populations.