| Radio Frequency Identification is an automatic technology which can realizecommunication with wireless RF signals. As collecting and processing informationrapidly and accurately, RF technology can indentify several tags at the same time andhigh speed objects. In recent years, RF technology has been widely used in the fieldsof production, logistics, transportation and so on. It is indicated that the technologywill have a good application prospect.In accordance of the understanding of the theory of RF system, this dissertationdiscusses a hardware design and realization of the ultra high frequency RFID readersatisfying EPC Gen2protocol. The reader includes three parts: RF part, control partand antenna. The RF part is based on the integrated chip AS3991, using on-boardintegrated PLL， frequency synthesizer, VCO, modulator, etc. Microcontroller PIC24Fis used to configure AS3991，while RF transformers and lumped parameter elementsare also utilized for channel matching. The drawing of the schematic and PCB of thewhole system is completed using Altium Desiner6software. The reader which has beenmanufactured and debugged can identify the tags successfully. The recognitiondistance is0.7meter when using integrated power amplifier. External power amplifieris applied in order to increase the identification distance. And it can be improved to5.5meter by means of the external power amplifier.Two kinds of RF reader CP antennas are also presented in the dissertation. Abi-directional CPW-fed antenna adopting bent monopole structure is designed.Experimental results show that the CPW-fed antenna possesses an impedancebandwidth of about20%(0.81GHz-0.989GHz) and a3dB AR bandwidth of24%(0.815GHz-1.04GHz). Another rectangular microchip antenna with rectangular cornercutting realizes circular polarization and the double layer patch structure enlarges thebandwidth. This microchip antenna reaches an impedance bandwidth of about10.2%(842MHz-932MHz) and a3dB AR bandwidth of7%(865-925MHz). |
PDF Full Text Request