Design And Realization Of The UHF RFID Reader Based On Independent Standard

The Radio Frequency Identification, especially UHF RFID technology, is playing an important role in military logistics management, equipment protection and maintenance.etc. In 2011, our country promulgated the RFID air interface military standard. Because of the incompatibility of standard, the existing RFID reader has not been able to use. So the research on the RFID equipment which is based on the independent standard is carried out. This paper focus on the key problems such as the power amplifier predistortion and carrier suppression in the design and realization of the UHF RFID reader. The research has been applied to the UHF RFID reader currently.Firstly, the paper described the operating principle of the UHF RFID system, and analyzed the energy delivering between readers and tags. Then the general scheme of UHF RFID reader and the key issuses, such as amplifier predistortion, carrier suppression, receive sensitivity and system integration are studied.Secendly, the amplifier distortion in UHF RFID system has been researched. Through the comparison of several common methods of amplifier predistortion and considering the characteristic of UHF RFID reader, the paper proposed a new adaptive, LUT and FPGA based digital predistortion method. Simulation and experimental results show that the method can effectively solve the non-linear and characteristics drift problem due to temperature, humidity and other causes in power amplifier, improve the emission spectrum of 10 d B.Finally the paper researched the carrier leakage in UHF RFID system in-depth. Through the analysis of the mechanism of the carrier leakage, this paper presented a carrier suppression method with fast convergence, 360-degree phase shift, and no-noise introduce. The method used passive network, which reduced the receiver noise significant without worsen the SNR of received signal.. The experimental results has shown that this method can suppress the leaking signal of 40 d B with 28 d Bm transmit power, resulted in improved the sensitivity of 14 d B with BER of 10-5.