使用同相位閘極增益整流器之毫米波被動式RFID電子標籤

Abstract

射頻電子識別標籤系統(RFID)是一個發展成熟的技術並且被廣泛的使用在我們的日常生活當中，例如：校園IC卡、電子通行證、電子收費系統等等。此論文主要在探討RFID標籤(Tag)的設計，因為標籤的大小直接地決定RFID系統應用的廣泛性。由於使用非晶片天線，現行的RFID標籤有著較大的體積，限制了應用的多樣性，因為RFID標籤並無法鑲嵌或安裝在比自身體積要小的物體上。此論文所提出的RFID標籤使用了60 GHz下行與24 GHz上行為操作頻率，以達到縮小天線面積的效果。由於此RFID標籤為被動式標籤，整流器因此成為此標籤的關鍵電路，主要的功能是將在環境中所取得的射頻訊號轉換為標籤的供給電壓。隨著頻率的上升，RFID標籤對外界射頻訊號的敏感度將會降低，因為不可避免的雜散電容嚴重的降低整流器的效能。為了克服雜散電容的影響，本論文提出了同相位閘極增益整流器。由實驗的結果得知此電路達到-7 dBm的敏感度且在輸入功率為7 dBm時射頻轉直流的轉換效率達到20.65%，此效能在目前操作於毫米波範圍的整流器領域中獨占鰲頭。

Radio-Frequency identification (RFID) system is a well-developed technique and is everywhere is our daily life, such as campus IC cards, access cards, electronic toll collection, etc. Efforts have been made mainly on a RFID tag IC design since the size of a tag directly determines the variety of RFID applications. Current RFID tag has large physical size due to the off-chip antenna, which limits the RFID applications because a tag cannot be mounted on objects smaller than itself. In this thesis, a downlink/uplink operating frequency of 60/24 GHz is used in order to reduce the antenna size. Since the proposed tag is passive, it requires a rectifier which converts RF power collected from surroundings to dc output supply voltage. A design of a robust rectifier becomes the most important task needed to be accomplished because as the frequency moves higher, the sensitivity of a RFID tag decreases due to the inevitable parasitic capacitance which impact the rectifier’s performance significantly. To overcome the parasitic effects, this thesis proposes an In-Phase Gate-Boosting Rectifier (IGR) which is a new circuit technique. The implemented IC achieves a state-of-the-art -7 dBm sensitivity with a peak power conversion efficiency of 20.65% at 7 dBm input power in the millimeter-wave rectifier circuit design domain.