李學智臺灣大學：電信工程學研究所陳建宇Chen, Jian-YuJian-YuChen2007-11-272018-07-052007-11-272018-07-052006http://ntur.lib.ntu.edu.tw//handle/246246/58787在本篇論文中，對於射頻辨識 (RFID)系統中標籤回傳的信號，我們提出了兩種不同的偵測方法來解調：非同調偵測法與同調偵測法。在射頻辨識系統中，因為反射場的量比起環境產生的雜訊要小的多；所以在提出的同調偵測法之中，反射場的大小與相位都將被利用來解調變信號，如此讀取機的偵測能力將得以增加。 我們架設了一個反射場的量測系統，並用其來量測與分析在不同天線負載、不同傳送接收天線與不同傳送能量下反射場的辨識能力。我們模擬並量測真實射頻辨識系統的回傳信號，利用提出的兩種偵測識方法做辨識；同調偵測的表現會比非同調偵測好。除此之外，我們利用不同的阻抗值來做負載阻抗調變(Impedance loading)。在不同的負載阻抗與不同的標籤反射天線下，偵測回傳信號的能力將會有所區別。根據以上得到的結果，我們提出了一種新的標籤天線架構，用以增加標籤的辨識率。 另一方面，標籤天線阻抗與晶片阻抗之間的匹配狀態是標籤天線設計中一個很重要的課題。因此，在本論文的最後，我們設計實驗並進行量測，並利用得到的結果分析匹配狀態與反射信號振幅差距的關係。In this thesis, we propose two detection methods for RFID system: the incoherent detection and the coherent detection. In the RFID system, the amount of the backscattered field is very small compared to the field introduced by the environment and we can increase the detection capability by considering both the magnitude and the phase information of the backscattered field, which is the basic principle of the coherent detection method. We construct a system for the measurement of the backscattered field of the RFID system. When discussing the detection capability, the effects of utilizing different types of antennas and adopting different transmitting power are investigated. We generate and measure the backscattered signal and the two detection methods proposed are used for the demodulation. The performance of the coherent detection is better than the incoherent detection. Besides, the effects on detection capability with different loading impedances are also discussed. In addition, the matching state between the tag antenna and the IC is another important issue in the design of the tag antenna. Therefore, the relation between the matching state and the level difference of the backscattered signal is also investigated.Abstract Ⅰ Contents Ⅲ List of Figures Ⅶ List of Tables XI Chapter 1 Introduction 1 1.1 Development of RFID 1 1.2 RFID Transmission Concept 2 1.3 Motivation and Organization of the Thesis 3 Chapter 2 Background 5 2.1 Signal Transmission in RFID 5 2.2 RCS (Radar Cross Section) Analysis 6 2.3 Principles of Impedance Loading 11 Chapter 3 RFID Backscattered Field Measurement and Detection Analysis 15 3.1 Theory of the Backscattered Field 15 3.1.1 The Model of the Backscattered Field 15 3.1.2 Vector Relations between the Antenna mode Component and the Residual Mode Component 18 3.1.3 Measurement Result of Backscattered Field Using Monopole Antenna as the Backscattering Antenna 21 3.2 Backscattered Field Measurement System 24 3.2.1 Measurement System Description 24 3.2.1.1 System Architecture 24 3.2.1.2 Signal Transmission of the Measurement 26 3.2.1.3 Operation Principles of Switch 27 3.2.2 Measurement System Settings 27 3.2.2.1 Measurement System Parameters 28 3.2.2.2 Switch Settings and the Measurement Procedures 30 3.3 Measurement Result for Range Detection 32 3.3.1 Measurement Result Utilizing Monopole Antennas as Transmitting and Receiving antennas under 0 dBm Transmitting Power 33 3.3.2 Measurement Result Utilizing Horn Antennas as Transmitting and Receiving antennas under 0 dBm Transmitting Power 38 3.3.3 Measurement Result Utilizing Horn Antennas as Transmitting and Receiving antennas under 10 dBm Transmitting Power 43 Chapter 4 Analysis and Measurement of Backscattered Signal Detection 49 4.1 Incoherent and Coherent Detection Methods 49 4.1.1 Received Signal Model 50 4.1.2 Incoherent Detection Method 52 4.1.3 Coherent Detection Method 55 4.1.4 Comparison between Coherent Detection and Incoherent Detection 58 4.2 Measurement and Analysis for Detection 59 4.2.1 Measurement System Architecture 59 4.2.2 Measurement Result for the Anechoic Chamber 63 4.2.3 Measurement Result for the Corridor 64 4.2.4 Analysis for Detection 66 4.3 Design of Tag Structure 69 4.4 Detection Analysis for EPCglobal Class-1 Generation-1 System 71 Chapter 5 Effect of Impedance Loading on Tag Antenna of RFID System 77 5.1 Signal Transmission in EPCglobal Class-1 Generation-1 and Generation-2 RFID Systems 78 5.1.1 Signal Transmission in Generation-1 RFID System 78 5.1.2 Signal Transmission in Generation-2 RFID System 79 5.2 Theory of Measurement 83 5.3 Measurement Setup 86 5.4 Measurement Result for Generation-1 System 88 5.4.1 Measurement Setting 88 5.4.2 Measurement Result for First Constant Resistance Circle 89 5.4.3 Measurement Result for Second Constant Resistance Circle 92 5.5 Measurement Result for Generation-2 System 95 5.5.1 Measurement Setting 95 5.5.2 Measurement Result for First Constant Resistance Circle 96 5.5.3 Measurement Result for Second Constant Resistance Circle 98 Chapter 6 Conclusion 101 References 1056256823 bytesapplication/pdfen-US射頻辨識負載阻抗調變雷達截面積波型匹配濾波器反射場同調偵測非同調偵測Radio Frequency IdentificationRFIDImpedance loadingRadar Cross Sectionmatch filterbackscattered fieldcoherent detectionincoherent detectionthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/58787/1/ntu-95-R93942012-1.pdf