Concern for the growing use of wireless devices, such as mobile phones, that expose a user’s head to electromagnetic (EM) field energy has motivated a number of studies on the effects of EM radiation on the brain. An important part of that research is to develop accurate models of the human head for simulating the effects of EM radiation on human tissues.
One research team has created a human-head model for studying the effects of different EM specific absorption rates (SARs) on the human brain. This high-resolution model allows for accurate simulation of 49 different tissues and organs within the human head. It is hoped that work with the model will lead to the design of safer multiple-band antennas for wireless electronic products.
Research on the EM head model was performed by investigators mainly in China, but also in the United States. The engineering team consists of Lei Zhao, director of the Center for Computational Science and Engineering and associate dean of the School of Mathematics and Physics of Jiangsu Normal University of China; Qin Ye, a visiting scholar at the School of Biology of Jiangsu Normal University of China; Ke-Li Wu, a professor at The Chinese University of Hong Kong; Geng Chen, a visiting student at the Center for Computational Electromagnetics at the University of Illinois; and Wenhua Yu, a visiting professor at Jiangsu Normal University of China and director of the Jiangsu Big Data Key Lab for Education Science and Engineering.
The new human-head model is meant to provide further insights into EM exposure levels from such devices as closely held cellular phones, in addition to the calculated SARs used by various regulatory bodies for determining safe EM exposure limits.
This first Chinese EM human-head model (CMODEL) was developed at The Third Military Medical University and the Chinese University of Hong Kong, initially based on photographs of a female human head. Great attention was paid to preserve the integrity of different structures and materials, such as teeth, within the head model.
Cross-sectional imaging and measurements were used to identify the different visible biological tissues. Data on a large number of tissues were provided by the U.S. Federal Communications Commission (FCC), including fat, muscle, grey matter, cartilage, blood, and spinal cord nerve tissue. Different colors were used in the head model to identify the energy paths for different tissues.
To validate the head model, three versions with different dimensions were developed and subjected to EM energy from a dual-band mobile-phone antenna operating at 900 and 1,800 MHz. The final model achieved a resolution of 0.16 × 0.16 × 0.25 mm3 for the head and 0.16 × 0.16 × 0.5 mm3 for the shoulder. The electric properties of the tissues in this model, which includes highly detailed sub models for eyes and ears, exhibit the same properties as the properties of tissues for SAR assessment, as published by the FCC. It represents another valuable tool in studying the effects of short-range EM radiation on wireless-device users.
See “A New High-Resolution Electromagnetic Human Head Model,” IEEE Antennas & Propagation Magazine, Vol. 58, No. 5, October 2016, p. 32.
