Thermal Distribution based Investigations on Electromagnetic Interactions with the Human Body for Wearable Wireless Devices

With increasing interest in the usage of wearable wireless communication technologies at 1.8 & 2.4GHz and 5 & 8.9GHz band of frequencies, investigations on the human body interaction with these devices are becoming important. This paper provides a microstrip-based multi-band monopole antenna for body Wearable Wireless Devices (WWD), covering licensed and license-free wireless technologies at UHF/UWB when placed on human body. Five parts of the body were considered to evaluate the electromagnetic ( EM) effects on the body. Specific Absorption Rate (SAR) values were found to range from 0.09-0.25 W/kg by using numerical modeling. The thermal effects were investigated experimentally using infrared thermography, and temperature changes not exceeding 1 degrees C were noticed. Analyses of numerical, simulated and experimental results show that infrared thermography, a temperature-based technique, can be used to evaluate the compliance of WWDs with safety exposure limits for various wireless applications.