SAR calculation & temperature response of human body exposure to electromagnetic radiations at 28, 40 and 60 GHz mmWave frequencies

Abstract

The fast development of millimeter wave (mmWave) wireless communications and the associated concerns of potential negative impact on human health instigates the study on effects of mmWave frequency on the human body after exposure to electromagnetic field in terms of specific absorption rate (SAR) and temperature rise in computer simulation technology (CST). SAR distributions due to radiating source antenna were investigated using the finite difference time domain (FDTD) method in single and layered human tissues by examining the 1 g SAR (gram mass averaging) and point SAR (without mass averaging) at mmWave frequencies of 28, 40 and 60 GHz. The bioheat equation was used to find the temperature elevation in tissues. The FDTD grid size used in the computation was 1.00, 0.75, and 0.50 mm at 28, 40 and 60 GHz, respectively. The results concluded that at the radiated power of 20 and 24 dBm, SAR levels (without mass averaging) in the tissues at 28 GHz were less than 40 and 60 GHz. It was found that the temperature increase in the three layer model was 2–3 times higher than that in the single layer model. However, the temperature elevation never exceeded 1◦C in all the determined cases which was well below the threshold value for the generation of any adverse thermal effects in the tissues. Moreover, the effect of distance between the source and tissue model was investigated. It was found that the SAR decreased as the distance increased from the radiating source. The results presented here will assist researchers in examining and simulating the performance of upcoming mmWave wireless networks in terms of exposure to human tissues.