【摘要】：無源超高頻射頻識別(UHF RFID)技術可以在非接觸的條件下實現(xiàn)對目標對象的自動識別,是物聯(lián)網(wǎng)的核心支撐技術之一。閱讀距離遠、通信速率快、適應物體高速運動等優(yōu)點,是工作于超高頻頻段的射頻識別系統(tǒng)相對于其它頻段的射頻識別技術而言所具有的優(yōu)勢。本文首先對UHF RFID的系統(tǒng)組成、工作原理進行了簡單的介紹,并對正向和反向的能量與數(shù)據(jù)傳輸方式進行了介紹,再此基礎上,通過分析計算,得出了標簽芯片的功耗是限制通信距離的主要因素。然后,本文提出了一種完整的標簽芯片系統(tǒng)方案,并分別對射頻前端、模擬前端、數(shù)字基帶和存儲器做了詳細的介紹。特別的,本文提出了一種全CMOS超高效率的閾值補償倍壓整流電路,其在可能的輸入能量范圍內(nèi),倍壓整流電路的效率值都不低于50%。通過分析計算,結合存儲器的需求,得出存儲器讀操作高壓管控制電壓是限制芯片通信距離的主要因素,在此基礎上,提出了一種帶有倍壓功能的穩(wěn)壓電路,使標簽的讀取距離由5.1米擴展到了6.8米。當射頻識別技術與傳感器技術相結合時,其應用場合將會得到非常大的擴展�；诖�,在分析了傳統(tǒng)溫度傳感器應用于UHF RFID標簽芯片中時面臨的問題后,本文提出了一種適用于UHF RFID標簽芯片的溫度傳感器,采用了雙振蕩器的結構,提高了傳感器的魯棒性。并且,采用了時分模式,在系統(tǒng)上電和命令到來之間的時間間隙進行溫度檢測,因此并不影響標簽的通信距離。通過測試,在不影響通信距離的前提下,溫度傳感器在-40℃到85℃范圍內(nèi),最大誤差為±1.5℃。再次,考慮到通信的安全性,本文在分析了常用的幾種數(shù)字方式產(chǎn)生隨機數(shù)的方案,并總結出其缺點后,提出了兩種適用于UHF RFID應用的隨機數(shù)發(fā)生器。一種采用電阻的熱噪聲作為隨機源,通過放大器,由D觸發(fā)器進行采樣輸出。放大器采用低功耗技術,整體隨機數(shù)發(fā)生器的功耗僅為800nW。另一種隨機數(shù)發(fā)生器是在前文提出的溫度傳感器基礎上,利用時鐘抖動得到隨機數(shù),與溫度傳感器類似,采用時分模式,并不影響標簽通信距離。最后,本文提出的標簽芯片在中芯國際CMOS 0.18μm EEPROM 2P4M工藝下,采用多項目晶圓(MPW)的方式來實現(xiàn)。采用兩種方式對芯片進行了詳細的測試。首先,采用芯片綁定在印制版(COB)封裝,標簽與閱讀器采用有線的方式進行連接,通過示波器對波形進行觀察,給出了一些關鍵信號的波形。其次,采用倒裝封裝,模擬真實應用場景,對標簽進行測試,結果顯示,最遠讀取距離大于6.8米,最大可寫入距離為1.8米,平均讀取速率達到了66個/s。
[Abstract]:Passive UHF radio frequency identification (UHF RFID) technology is one of the core supporting technologies in the Internet of things (IoT), which can realize the automatic identification of the target object under the condition of non-contact. The advantages of long reading distance, fast communication rate and high speed motion of objects are the advantages of RFID system which works in UHF band compared with other RFID technology. In this paper, the system composition and working principle of UHF RFID are introduced briefly, and the forward and reverse energy and data transmission modes are introduced. It is concluded that the power consumption of the tag chip is the main factor limiting the communication distance. Then, a complete tag chip system is proposed, and the RF front-end, analog front-end, digital baseband and memory are introduced in detail. In particular, a threshold compensated double voltage rectifier circuit with full CMOS ultra-high efficiency is proposed. In the range of possible input energy, the efficiency of voltage doubling rectifier circuit is not less than 50. Through analysis and calculation, combined with the demand of memory, it is concluded that the control voltage of high voltage tube in memory read operation is the main factor limiting the communication distance of chip. On the basis of this, a voltage stabilizing circuit with voltage doubling function is proposed. Extended the read distance of the tag from 5.1 m to 6.8 m. When RFID and sensor technology are combined, the application of RFID will be greatly expanded. Based on this, after analyzing the problems of traditional temperature sensor applied in UHF RFID tag chip, this paper presents a temperature sensor suitable for UHF RFID tag chip, which adopts the structure of double oscillator. The robustness of the sensor is improved. Moreover, time division mode is used to detect the temperature between the time interval between the power supply and the arrival of the command, so the communication distance of the label is not affected. The results show that the maximum error of the temperature sensor is 鹵1.5 鈩，

本文編號：2401378