應用於毫米波被動式射頻辨識電子標籤之高敏感度射頻能量攫取器

Abstract

物聯網的概念最早於1990年代被提出來，近年來由於無線通訊技術的演進讓物聯網開始變得熱門，進一步激發我們對於未來生活有了新想像。實現物聯網主要技術在於射頻辨識系統(簡稱RFID系統)，而RFID系統已經發展一段時日，應用於許多生活中像是ID卡、存取控制、電子通行收費等。在RFID系統中，RFID電子標籤扮演一個關鍵角色。目前常見的RFID電子標籤運作在特高頻段(902-928MHz)，因為運作頻段的緣故，此類電子標籤採用的晶片外天線之體積和尺寸相對較大。為了縮小RFID電子標籤整體體積，將電子標籤的運作頻段抬升是一個顯然的發展方向。然而，一旦運作頻段上升，電磁波傳遞過程中的能量消耗會變大。因此，尤其針對全被動式RFID電子標籤，能量攫取的研究主題吸引了許多關注和興趣。 在此篇論文中，以同相位閘極增益整流器為基礎，提出一個強化能量攫取的創新電路架構，此電路架構額外包含了電源管理器和直流升壓轉換器，希望可以推進能量攫取器之整體敏感度。進一步此能量攫取器將會整合進35GHz全被動式RFID電子標籤，希望可以達到RF對DC轉換效率增加和低功耗無電池之標籤系統運作。

The concept of Internet of Things (IOT) was proposed first in 1990s. IOT has become popular in recent years because the evolution on wireless communication prompts people to envision a new life with IOT in the future. The main technology to realize IOT is the radio frequency identification (RFID) system which is well-developed and applied on such as ID cards, access control, and electronic toll collection in the past years. In the RFID system, a RFID tag plays a critical role and it needs to operate driven by a power source. Current RFID tags operate in the UHF frequency band (902-928MHz) and have a larger physical size due to the off-chip antenna which is corresponding the operation frequency. In order to shrink down the tag size, raising the operation frequency is an obvious development direction. However, the power loss of the electromagnetic wave becomes larger with the increase of the operation frequency. Especially for passive battery-less RFID tags, the energy harvesting issue has attracted increasing attention and interests. In this thesis, based on the in-phase gate-boosting rectifier design [Wang 2014], a novel circuitry structure of energy harvester including a power-on reset circuit and a boost converter is proposed to improve the sensitivity for the energy scavenging with 35-GHz RF input power. Further, this energy harvester is utilized on a 35-GHz passive RFID tag to target the main two issues: 1. Performance of RF-DC conversion. 2. Low power battery-less system operation.