日本人モデルを用いた無線機器の胴体装着時におけるSARと温度上昇評価

摘要

日本人数値モデルを用いて無線機器の胴体装着時における10g平均SAR（Specific Absorption Rate）と温度上昇について検討を行った．波源は通常良く用いられる半波長ダイポールとし，胴体内部に生ずる電界をFDTD（Finite-Difference Time-Domain）法を用いて求め，10g平均SARを算出した．また，得られたSARを用いて生体熱輸送方程式にて胴体内部における温度上昇を求めた．吏に用いた周波数は，現在携帯電話で用いられている900，1950MHz帯に加え，将来第4世代で使用が予定されている3500MHzとした．その結果，10g平均SARと温度上昇ともに1950M比が一番高く，今回着目したより高い周波数の3500MHzでは10g平均SARおよび温度上昇とも1950MHzより高くならないことがわかった．また，10g平均SARと温度上昇の間によい相関があることを確認した．%l0g average SAR (Specific Absorption Rate) and temperature evaluation are investigated using the Japanese numerical anatomical models when devices are mounted on the body. A half-wave dipole is assumed as a radiation source and generated electrical field and the SAR are calculated by the FDTD (Finite-Difference Time-Domain) method. Then the bio-heat equation is solved to obtain the temperature elevation based on SAR distribution derived by the FDTD method. The frequencies used in the study are 900 MHz and 1950 MHz, which have been used for the cellular phone. In addition, 3500 MHz is used because this frequency has been reserved for the IMT-advance. As a result, .the lOg average SAR and the temperature elevation at 1950 MHz are higher than those at the other frequencies, hi addition, it is clear that those at 3500 MHz are lower than that at 1950 MHz even though the frequency is higher. It is shown that there is a good correlation between the 10g average SAR and the temperature elevation.