應用Metamaterial空腔之無線傳能系統及其關鍵電路設計

A Wireless Power Transmission System Using Metamaterial Cavity and Its Key Components Design

李明龍(Ming-Lung Lee)

指導教授 ： 毛紹綱

國立臺北科技大學/電資學院/電腦與通訊研究所/碩士(2012年)

摘要

本論文提出兩個應用於metamaterial空腔之無線傳能系統的高功率且高效率的射頻整流器。由於矽製程的蕭特基二極體的低崩潰電壓特性，無法在高功率下操作，因此分別利用串聯式與並聯式功率分配變壓器，將輸入功率平均分配至四個全波橋式整流器，以降低跨接於二極體的偏壓。在耦合線段的實現部分，分別利用方形與同心圓形式的鑿空地面結構，增加其耦合係數。由量測結果可知，其輸入功率可操作在36 dBm以上，且在10 歐姆的重載條件下，其串聯式功率分配變壓器與並聯式功率分配變壓器構成的整流器，其量測的效率分別為59 % 與 73 %。為了降低功率傳輸的過程會經由空氣或物質作傳遞而產生傳輸功率的衰減及高功率電磁干擾的問題，本論文將應用一個封閉且具有產生強耦合特性的metamaterial空腔，用以提升系統的傳輸特性及改善電磁干擾的問題。
最後，將利用設計的兩個高功率射頻整流器，透過應用metamaterial空腔的無線傳能系統作手機充電的實驗，經由實驗結果可知設計的兩個高功率射頻整流器不僅達到高功率且高效率的特性，且能夠實際應用在行動裝置的無線充電技術中。

關鍵字

功率分配變壓器 ； 射頻整流器 ； 無線功率傳輸 ； metamaterial空腔

並列摘要

Two critical components are proposed for a wireless charging system of mobile handset, i.e. a metamaterial cavity using artificial magnetic conductor surfaces and a RF rectifier with high-power and high-effieency characteristics.
This wireless charging system demonstrates broad bandwidth, small size, long transmitting range, high transferring efficiency and EMI-free features.
To overcome the low breakdown voltage limit of silicon-based schottky diode, the series and parallel dividing transformers are employed to couple the high input RF power from single-ended into four differential-type bridge diodes. The proposed rectifiers are developed to withstand up to 36 dBm of input power before reaching the breakdown limit of Schottky diode, and their corresponding RF-to-DC power conversion efficiency is 59 % and 73% at operating frequency 920 MHz and the load resistance is 10 Ω.

並列關鍵字

power-dividing transformer ； RF rectifier ； wireless power transmission ； metamaterial cavity

參考文獻

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