Evaluation of Specific Absorption Rate of Microstrip and Monopole Patch Antenna on Human Forearm

The electromagnetic properties of the human bodies highly influence the performance characteristics of an antenna in a wireless body area network (WBAN). Specific absorption rate (SAR) is one of the most important criterions for the design of an antenna for WBAN. In this paper two types of antennas, the microstrip and monopole patch antennas are designed for the ISM band (2.4-2.5 GHz) application. Its performance characteristics are measured in free-space and in close proximity to the human body. In most of the cases, it becomes difficult to measure SAR due to lack of certified SAR measurement equipment, which are very costly. Hence, a simple and cost-effective SAR measurement method is also introduced to experimentally calculate SAR for different frequencies to check compliance with the safety guidelines. Finally, properties of both the antennas are compared in terms of SAR.