電機資訊學院: 電信工程學研究所指導教授: 陳士元程子恆Cheng, Tzu-HengTzu-HengCheng2017-03-062018-07-052017-03-062018-07-052016http://ntur.lib.ntu.edu.tw//handle/246246/276344在本論文中，吾人建構了用於收集溫室環境資訊之無線感測系統。所開發之硬體主要包含無線感測模組以及應用於讀取器之波束可切換之圓極化天線陣列兩大部分。 感測器模組主要採用德州儀器公司提供之MSP430G2553微控制器、Impinj Monza X-2k RFID雙介面晶片、Silicon Lab Si-7021溫濕度感測器、TAOS TSL-45315照度感測器, 以及自製之RFID標籤天線。微控制器控制所有感測電路模組的運作流程，包含感測、寫入及無線讀取。吾人所採用的感測器皆支援用於此類單一電路板內之短程訊息傳遞之I2C介面，並藉由I2C介面接收微控制器之指令，量測環境資訊，接著微控制器可將之寫入RFID晶片之記憶體內。利用RFID之Class 1 Gen 2無線介面，讀取器可在RFID晶片之記憶體未被I2C介面存取之任意時間點讀取前一次所測得之環境資訊。吾人亦提出兩款RFID標籤天線，其特色分別為微小化及高增益。兩款天線皆與感測模組電路整合，其特性亦透過量測結果和模擬結果之比較驗證。 讀取器之波束可切換天線陣列可細分為天線陣列本體及饋入網路兩部分。天線陣列部分。吾人採用L型殘段結構饋入正方形槽孔天線來產生圓極化輻射，配合金屬共振腔之包覆將波束集中在單一方向，並降低相鄰天線單元間之耦合。陣列尺寸受限於操作頻率與實驗室製作限制，本論文中僅實現一維陣列。其效能可達10 dBi以上之圓極化增益。饋入網路部分則由微帶線架構實現之十字形接面與兩個反射式相移器所組成。藉由調整十字形接面各分支線之特徵阻抗，輸出端之震幅大小可任意設計以改善陣列場型之旁波瓣位準。其中，反射式相移器由週期性附載之耦合線方向耦合器及二位元數位可調之負載電路所組成。德州儀器之MSP430G2553微控制器亦用於控制該饋入電路，使天線陣列之主波束能在四個選定方向間自動依序切換，以讀取不同方位之感測器模組之感測資料。In this thesis, a novel wireless environmental sensor system for use in advanced greenhouses is presented. The major contribution of this thesis includes the development of RFID sensor tags and the switched-beam circularly polarized (CP) antenna array as the reader antenna, both of which operate in the 902-928 MHz band. The sensor tag module consists of a Texas Instrument MSP430G2553 microcontroller (MCU), Impinj Monza X-2k RFID tag chip with dual interfaces, Silicon Lab Si-7021 integrated temperature and relative humidity sensor, TAOS TSL-45315 light sensor, and RFID tag antenna designed by ourselves. The MCU manages the whole operation procedure, including sensing, data writing, and wireless reading. All the devices in the sensor tag module are compatible with the I2C interface, commonly used in short range communication on PCB board. All the sensors can receive and follow the commands from MCU via I2C interface to measure the environmental information and then send back the data to MCU for it to write the sensing data into the nonvolatile memory (NVM) of the RFID tag chip. Through the RFID Class 1 Gen 2 air interface, RFID reader can wirelessly access the data stored in the tag chip whenever the NVM is not accessed by MCU via I2C interface. Besides, we also proposed two types of RFID tag antennas, one with a compact size and the other having a higher gain. These two antennas are integrated respectively with the sensor tag module, and their performances are verified by comparing the simulated and measured results. The proposed switched-beam CP cavity-backed slot antenna array for use as the RFID reader antenna consists of two parts: the array of radiators and its feeding network. The element radiator is a square slot backed by a metallic cavity and fed by an L-shaped strip to obtain uni-directional CP radiation and lower mutual coupling between adjacent elements. In this thesis, an one dimensional array is implemented considering the limitations imposed by our in-house fabrication process and the operating frequency of the system. The peak gain achieved is about 10 dBi. Our proposed feeding network consists of a microstrip cross junction and two reflection-type phase shifters (RTPSs). By properly choosing the characteristic impedances of the four branches of the cross junction, arbitrary current distribution at the three outputs branches can be obtained to feed into the array elements. The side-lobe level (SLL) of the switched-beam antenna array can readily be improved by implementing a tapered current distribution. The novel RTPS consists of a periodically loaded coupled-line coupler and two identical 2-bit switchable termination circuits, which is also controlled by the TI MSP430G2553 MCU. The RTPS is the key for the automatic sequential beam switching of the array between four predetermined directions.4982541 bytesapplication/pdf論文公開時間: 2021/8/26論文使用權限: 同意有償授權(權利金給回饋學校)金屬共振腔槽孔天線圓極化反射式相移器波束可切換之天線陣列無線感測網路cavity-backed aperture antennascircular polarizationreflection-type phase shiftersswitched-beam antenna arrayswireless sensor networkthesis10.6342/NTU201603250http://ntur.lib.ntu.edu.tw/bitstream/246246/276344/1/ntu-105-R03942013-1.pdf