降低行動電話對人體頭部電磁特定吸收率之研究

Reduction of Specific Absorption Ratio inside the Head of a Cellular-Phone User

邱維毅(Wei-YI Chiou)

指導教授 ： 陳 興 義 ； 周 錫 增

元智大學/工程學院/電機工程學系/碩士(2002年)

摘要

本論文利用時域有限差分法 (FDTD) 來研究手機材料對於人體頭部內感應之電磁特定吸收率 (SAR) 的影響。根據台灣成年人頭部的解剖圖，非均勻人體頭部模型是由邊長2.5毫米共450,872細胞立方塊所組成。有許多不同類型的手機模型包含半偶極天線、均勻手機機身和不均勻手機機身被使用來當作手機的模型。手環抱在手機下半部的三邊上和且手的組成以骨頭為核心再圍繞著一層的肌肉，此模型被當作來模擬真實使用手機的情況。在研究中將展示出具有不同材料手機輻射所感應於人體頭部內之局部最大SAR值。從研究的結果中可以發現到用較小介電常數和導電率的手機可以降低較多感應於人體頭部之SAR值。從研究中亦發現到用介電材料和導磁材料混合製造的手機可以明顯降低人體頭部內感應之SAR值。其中也發現到用介電材料製造不同大小尺寸的手機不是影響人體頭部內感應SAR值的主因。然而用導電材料製造的大尺寸手機可以感應出比較大的人體頭部SAR值。最後，本研究所得結果將可提供作為手機設計時寶貴的參考資料。

關鍵字

時域有限差分法 ； 電磁特定吸收率 ； 半偶極天線 ； 均勻手機機身 ； 不均勻手機機身 ； 介電常數 ； 導電率 ； 導磁材料

並列摘要

In this thesis, the Finite-Difference Time-Domain (FDTD) method is used to study the material effectiveness of cellular phones for reducing specific absorption rate (SAR) induced inside a human head model. Based on the anatomical chart of Taiwanese adult head, the inhomogeneous human head model is constructed with 450872 cubical cells of dimension 2.5mm. Many different models including half-wave dipole antenna, homogeneous phone body, and inhomogeneous phone body are used for modeling the cellular phone. A hand wrapping around three sides of the lower half of cellular phone and consisting of a core of bone surround with a layer of muscle is adopted for the simulations for practical use of cellular phone. Results of maximum local SAR’s induced inside a human head model under the irradiation of cellular phones with different materials are presented. From the obtained results, it is found that cellular phones with smaller dielectric constants and conductivities can reduce much more SAR induced inside a human head model. It is also found that cellular phones manufactured with dielectric material mixed with magnetic material can remarkably reduce SAR induced inside a human head. It is also found that the size of a cellular phone manufactured with dielectric material is not key factor of the affection of SAR induced inside a human head. However, a larger cellular phone manufactured with conducting material can be induced larger SAR inside a human head. Results obtained from this study provide a valuable knowledge for cellular phone design.

並列關鍵字

Finite-Difference Time-Domain ； specific absorption rate ； half-wave dipole antenna ； homogeneous phone body ； inhomogeneous phone body ； dielectric constants ； conductivities ； magnetic material

參考文獻

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