射頻辨識系統(RFID)中的標籤，一般都有限定使用的材質，因為當標籤貼附於各種不同材質的表面時，標籤天線會因為材質的不同，產生高頻的效應，而天線阻抗有相當大範圍的改變，此變化將造成標籤天線與標籤系統電路間有著嚴重的阻抗不匹配，因而降低了能量的傳輸。在此論文中，為了能夠使標籤的使用的材質範圍更廣，我們希望材質的介電常數變化是由1到10，而提出一個低複雜度的適應性阻抗匹配電路(Adaptive Impedance Matching Network)，此阻抗匹配電路不採用電感，而都是由電容所組成，目的是希望能夠減少在晶片製作上的面積，此電路的功能，在於能夠透過電容的串、並聯，以補償天線與晶片間，阻抗不匹配的情形，促使讀碼系統接或標籤系統都能夠接受或者發射更多的能量。為了完成此電路的設計，我們首先針對標籤天線的阻抗做單一頻率分析，當所貼附的材質其介電常數增加時，觀察標籤天線阻抗在915(MHz)下的變化情形，找出一個趨勢。再者針對阻抗的變化，透過電容的串聯或並聯將輸入阻抗補償至最佳的匹配點，電容值的選擇是以二進位的方式安排，至於電容的各數，將視阻抗變化而定。最後功率效率的模擬，我們會將標籤在有適應性阻抗匹配時的能量與沒有匹配電路時的能量加以計算分析，當有適應性阻抗匹配電路時的能量傳輸效率遠優於沒有匹配時的情形。由於天線與匹配電路是各自獨立的，因此即使將天線改變了，適應性阻抗匹配電路，依舊可以使用。

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