The Design And Implementation Of RF Front-end Circuit That Conforms To Multi–protocol UHF Accord

As the basis of information standardization and a high technology that can collect and process the data precisely, rapidly and in real time, RFID technology has been acknowledged as one of the most important technologies in 21 st century worldwidely. the publishment of new national standards play a crucial role in promoting the development of the independent RFID industry in our country.This paper aims to design the transceiver of RF front end that conforms to national standards and ISO/IEC18000-6c protocol at the same time. The transceiver adopts the circuit structure of combining transmitter with receiver. The transmitter adopts ASK quadrature modulator, the frequency is 920MHz~925MHz, output power is 3 dBm~33dBm, the precision of frequency is 174 Hz,the step frequency is 250 KHz,the step power is 0.5dB,output three order intercept point is 32.74 dBm. the receiver adopts direct conversion structure,the sensibility of the receiver is-80 dBm,the dynamic range is 78.97 dB,noise figure is 20.28 dB, input three order intercept point is-2.674 dBm,input 1dB compression point is-2.5dBm.This paper mainly talks about the design, simulation and test of the frequency synthesizer circuit and tranceiver. Through the learning of theoretical knowledge and reading of the relevant papers, RFID system, two protocols and the structure of the frequently-used transmitter and receiver are introduced theoretically. Besides, transceiver circuit index designed in this paper is presented, the link budget and simulation of the transceiver are also conducted by using ADS, including power control and linearity of the transmitter and the noise figure, linearity, dynamic range of the receiver and so on. Moreover, the frequency synthesizer circuit is analyzed according to daily accumulation, the design and simulation of frequency synthesizer circuit used in this transceiver are conducted, including the analysis of loop filter, phase noise, spurs and so on. Meanwhile, the specific circuit modules of this transceiver are introduced in this paper, including isolation adjustment, power amplifier, ASK modulation, power detection circuit, PCB design and so on. At last, the test of the actual RF circuit is conducted, the test result is presented and analyzed.