手機頻率專用的電磁波吸收之設計

近年手機將資訊融入生活，日漸普及已成爲生活的必需品。當手機所產生的低輻射量電磁波大量地曝露於生活空間，可能產生電磁環境污染問題。本研究旨在降低手機所產生的電磁輻射，提出手機頻率用的電磁波吸收之解決對策並詳述電磁波吸收的設計方法。本研究分析出電磁波吸收性能與材料厚度及複數介電係數有互相依存之關係。並且分析出材料厚度與頻率是成反比例的關係。選擇d/λ=0.06將吸收材料的厚度設定爲d=2.0 cm且複數介電係數的值爲έ(下標 r)=17.7-j5.1或選擇d/λ=0.15將吸收材料的厚度設定爲d=5.0 cm且複數介電係數的值爲έ(下標 r)=3.2-j1.9時，均可在手機用頻率0.9 GHz處得到20 dB以上的電磁波吸收性能之反射衰減量。在d/λ=0.15的場合，材料厚度從5.0 cm降低至2.5 cm及2.37 cm，頻率由0.9 GHz升至1.8 GHz及1.9 GHz處均可得到28 dB相同的反射衰減量。

關鍵字

手機；電磁輻射；電磁波吸收

並列摘要

Along with scientific and technology movement, people are used to cellular phone in every aspect of the daily life, the outcome is that electromagnetic radiation increased constantly. The purpose of this research tried to reduce the electromagnetic radiation arise from the cellular phone. This paper proposed that the settlement countermeasure is electromagnetic wave absorption for cellular phone, and explain the design method of electromagnetic wave absorption in detail. This paper analyzed that electromagnetic wave absorbing performances depend on the suitable thickness and complex permittivity of material, also the relation between thickness and frequency are in inverse proportion. When the complex permittivity and the thickness of material are chosen as έ(subscript r)=17.7-j5.1 and d=2.0 cm in d/λ=0.06 or έ(subscript r)=3.2-j1.9 and d=5.0 cm in d/λ=0.15, electromagnetic wave absorbing performance obtained return loss above 20 dB at 0.9 GHz for cellular phone. In the case of d/λ=0.15, The absorbing performance obtained return loss of the same 28 dB at 0.9 GHz, 1.8 GHz and 1.9 GHz respectively when thickness is changed from 5.0 cm to 2.5 cm and 2.37 cm.

並列關鍵字

Cellular Phone ； Electromagnetic Radiation ； Electromagnetic Wave Absorption

參考文獻

Kim, K. Y.,Kim, W. S.,Hong, S. Y.(1993).A study on the behavior of laminated electromagnetic wave absorber.IEEE Transactions on Magnetics.29(3),2134-2138.