Numerical Evaluation of Specific Absorption Rate in Human Brain Tissues at 24 and 40 GHz 5G Millimeter-Wave Bands

The deployment of fifth-generation (5G) wireless communication systems has led to the increased use of millimeter-wave (mmWave) frequencies, rising scientific and public interest regarding potential health implications of human exposure to non-ionizing electromagnetic radiation (EMR). In this paper, the Specific Absorption Rate (SAR) distribution within the human brain is numerically assessed under exposure to 5G mmWave radiation in the 24–40 GHz 5G band. A high-resolution, anatomically realistic human head model comprising multilayer tissues—including skin, skull, cerebrospinal fluid, gray matter, and white matter—is employed for mathematical calculations. To evaluate SAR inside human brain (scalp) due to non ionizing electromagnetic radiation (EMR) mathematical modeling is used. the Localized and spatially averaged SAR values are evaluated for realistic near-field exposure scenarios representative of handheld 5G devices. The results indicate that maximum SAR occurs predominantly tissues, with rapid attenuation toward deeper brain regions due to the limited penetration depth of mmWave radiation. The Brain tissue maximum SAR values are found to be significantly lower than those values reported for mm wave frequencies of 5 G bands and remain well below the limits prescribed by international safety guidelines which are given by ICNIRP, NCRP, WHO, etc. However, localized SAR enhancement is observed near tissue interfaces, emphasizing the need for detailed anatomical modeling. The findings contribute to a refined understanding of mmWave energy deposition in the human brain and provide scientific support for exposure compliance assessment and safety evaluation of emerging 5G technologies.