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  本文選題：無線射頻識別技術 + 超高頻近場系統(tǒng)��； 參考：《杭州電子科技大學》2015年碩士論文

【摘要】：隨著互聯(lián)網(wǎng)和通信技術的日益成熟，物聯(lián)網(wǎng)（IoT）這個新興概念越來越多的被人所提及，而作為物聯(lián)網(wǎng)核心技術的無線射頻識別技術（RFID）也被廣泛的應用于物流、制造、公共安全等領域中。一直以來，RFID技術的應用方向分為超高頻的托盤級識別和高頻/低頻的物品級識別，在同一頻段同時實現(xiàn)托盤級識別和物品級識別一直備受關注，超高頻近場系統(tǒng)被認為是解決這一難題的主要方案。 天線是RFID系統(tǒng)中的一個重要組成部分，直接影響著整個系統(tǒng)的工作性能。本項目的近場系統(tǒng)工作在天線的感應場區(qū)，采用電感耦合的工作方式，以環(huán)天線理論和半波偶極子天線理論為基礎，分別對近場系統(tǒng)的標簽天線和讀寫器天線展開研究： （1）通過分析超高頻近場標簽天線電路模型，提出偶極子天線加載電小環(huán)天線的天線結構。但由于尺寸的限制，單個偶極子臂有效長度不足以達到諧振頻率所對應的四分之一波長，故無法保證天線工作頻率達到設計要求；而且近場標簽要有較強的環(huán)境適應能力需要有塊狀結構形成大電容以增強儲存能量的能力。因此，提出一種特殊結構電小環(huán)集成圓弧形偶極子臂的天線結構，并用HFSS進行建模仿真，優(yōu)化設計后得到最優(yōu)結構和尺寸，最終仿真結果顯示天線中心頻率為910MHz，與芯片阻抗匹配，，電壓駐波比小于1.5。 （2）以讀寫器天線近場區(qū)域能夠產(chǎn)生均勻的電磁場分布為設計核心，提出反向電流對加載開口諧振環(huán)的天線結構：用偶極子臂構建反向電流對，用電小環(huán)天線構建開口諧振環(huán)，并用HFSS進行建模仿真，優(yōu)化設計后得到最優(yōu)結構和尺寸，仿真結果顯示讀寫器近場區(qū)域內(nèi)電磁場分布均勻，且具有較強的電場強度和磁場強度，天線中心頻率為920MHz，與50歐姆實現(xiàn)阻抗匹配，電壓駐波比小于1.5。 最后，對該超高頻RFID近場系統(tǒng)測試，測試結果顯示該系統(tǒng)閱讀性能良好，可達6.5cm；系統(tǒng)具有較強的環(huán)境適應性，貼附在各種材質(zhì)上的閱讀距離均可大5cm，但在金屬環(huán)境中使用時需離開金屬表面至少1cm。
[Abstract]:With the development of Internet of things and communication technology, the new concept of IoT has been more and more mentioned, and RFID, the core technology of Internet of things, has been widely used in logistics and manufacturing. In areas such as public safety The application of RFID technology has been divided into ultra-high frequency pallet level identification and high frequency / low frequency object level identification. UHF near-field system is considered to be the main solution to this problem. Antenna is an important part of RFID system, which directly affects the performance of the whole system. The near field system of this project works in the inductive field region of the antenna. Based on the theory of loop antenna and half wave dipole antenna, the label antenna and reader antenna of the near field system are studied by inductively coupled mode. 1) by analyzing the circuit model of UHF near-field tag antenna, the antenna structure of electric small loop antenna loaded with dipole antenna is proposed. However, due to the limitation of size, the effective length of a single dipole arm is not enough to reach the 1/4 wavelength corresponding to the resonant frequency, so it is impossible to guarantee the antenna working frequency to meet the design requirements. In addition, the near field tag needs to have a large capacitance to enhance the energy storage ability to have a large block structure to be able to adapt to the environment. Therefore, an antenna structure with a special structure, the electric small ring integrated circular arc dipole arm is proposed, and the optimal structure and size are obtained by HFSS modeling and simulation. The simulation results show that the center frequency of the antenna is 910MHz, which matches the chip impedance, and the VSWR is less than 1.5. Taking the near-field distribution of electromagnetic field in the near field of reader antenna as the design core, an antenna structure with reverse current pair loaded with open resonant ring is proposed: the reverse current pair is constructed by dipole arm, and the open resonant ring is constructed by electric small loop antenna. Using HFSS to model and simulate, the optimal structure and size are obtained after optimized design. The simulation results show that the electromagnetic field in the near field region of the reader is uniform, and has a strong electric and magnetic field intensity. The center frequency of the antenna is 920MHz, and the impedance is matched with 50 ohms. The VSWR is less than 1.5. Finally, the test results of the UHF RFID near-field system show that the reading performance of the system is good, which can reach 6.5 cm, and the system has strong environmental adaptability. The reading distance attached to various materials can be 5 cm, but when used in metal environment, it must be at least 1 cm off the metal surface.
【學位授予單位】：杭州電子科技大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TP391.44

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