Thermal Impact Assessment of Mobile Communication Frequencies: Novel SAR Formulation and Temperature Prediction in Human Tissue through Integrated Electromagnetic-Bioheat Modelling

Abstract

The widespread deployment of mobile communication technologies within the 700 – 900 MHz and 1.8 – 2.6 GHz frequency bands has raised concerns about electromagnetic wave exposure’s thermal effects on human tissues. This study investigates radiofrequency (RF) interactions with biological tissues. Use is made of Maxwell’s equations, the Cole-Cole dielectric dispersion model, and the Pennes’ bioheat transfer equation to derive relevant expressions needed for investigation of RF interactions with human tissue. Simulation results confirm a direct correlation between exposure duration and RF energy absorption. Lower frequencies penetrate deeper, depositing more energy per unit volume. After 60 minutes of exposure within a tissue volume, the absorbed thermal energy was 2.799 J (700 MHz), 2.729 J (900 MHz), 2.548 J (1.8 GHz), and 2.358 J (2.6 GHz). The corresponding peak temperature increases were 0.032°C, 0.026°C, 0.014°C, and 0.0085°C, respectively. Penetration depths were inversely proportional to frequency. Conductivity data showed increasing frequency leading to shallower penetration and more surface absorption. Indeed, at 5 mm penetration for example, SAR values calculated are (0.1130, 0.0881, 0.0334, and 0.0118 (W/kg)) for the four respective frequencies adopted here. The proposed computational framework provides an efficient and physically consistent approach for predicting SAR and tissue temperature under normal-incidence mobile communication exposure and may serve as a practical tool for future electromagnetic safety assessments.