Dosimetry and Verification for 6-GHz Whole-Body Non-Constraint Exposure of Rats Using Reverberation Chamber

Jingjing SHI  Jerdvisanop CHAKAROTHAI  Jianqing WANG  Kanako WAKE  Soichi WATANABE  Osamu FUJIWARA  

IEICE TRANSACTIONS on Communications   Vol.E98-B   No.7   pp.1164-1172
Publication Date: 2015/07/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E98.B.1164
Type of Manuscript: Special Section PAPER (Special Section on Electromagnetic Compatibility Technology in Conjunction with Main Topics of EMC'14/Tokyo)
specific absorption rate (SAR),  reverberation-chamber (RC) exposure system,  finite-difference time-domain (FDTD) method,  S-parameter measurements,  

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With the rapid increase of various uses of wireless communications in modern life, the high microwave and millimeter wave frequency bands are attracting much attention. However, the existing databases on above 6GHz radio-frequency (RF) electromagnetic (EM) field exposure of biological bodies are obviously insufficient. An in-vivo research project on local and whole-body exposure of rats to RF-EM fields above 6GHz was started in Japan in 2013. This study aims to perform a dosimetric design for the whole-body-average specific absorption rates (WBA-SARs) of unconstrained rats exposed to 6GHz RF-EM fields in a reverberation chamber (RC). The required input power into the RC is clarified using a two-step evaluation method in order to achieve a target exposure level in rats. The two-step method, which incorporates the finite-difference time-domain (FDTD) numerical solutions with electric field measurements in an RC exposure system, is used as an evaluation method to determine the whole-body exposure level in the rats. In order to verify the validity of the two-step method, we use S-parameter measurements inside the RC to experimentally derive the WBA-SARs with rat-equivalent phantoms and then compare those with the FDTD-calculated ones. It was shown that the difference between the two-step method and the S-parameter measurements is within 1.63dB, which reveals the validity and usefulness of the two-step technique.