Local exposure system for rats head using a figure-8 loop antenna in 1500-MHz band.

Cellular phones are used in the vicinity of the human head, resulting in localized exposure to this part of the body. To simulate exposure during cellular phone use, microwave energy absorption should be focused within the head region of laboratory animals. In this paper, we developed an exposure system using a figure-8 loop antenna to permit localized exposure of a rat head to 1500-MHz microwave fields, simulating human head exposure to cellular phones. We have numerically estimated the specific absorption rate (SAR) in a rat exposed to microwave fields via our new exposure system. The high ratio of SAR averaged over the target tissue (i.e., the brain) to that averaged over the whole body suggests that the figure-8 antenna can realize greater localized exposure than the previously used exposure system. We have also confirmed the effectiveness of our proposed system experimentally.