Research And Design Of RF Front-end ICs For 900MHz-RFID Receiver

Since 1990s, Radio Frequency Identification technology(RFID), as known as electronic tags, is interpreted as an automatic identification technology, which uses radio frequency signals through space coupling to achieve a non-contact transmission of information, and achieves the target recognition through the information.RF transceiver is the core of RFID systems, consisting of receiver and transmitter. This paper studied the RF front-end circuit of the receiver. Based on SMIC 0.18?m RF CMOS process, the main modules of the receiver have been designed and simulationed. The main contents are as follows:(1)The background of RFID technology, current research and its applications are introduced. And then the structure and working principle of each part of a RFID system are studied. Three classical RFID architecture and their structure and properties are introduced. Finally the performance metrics of the RF front-end are analyzed in detail.(2)A two-stage low noise amplifier is designed out. The first stage can obtain better noise figure due to the source inductance feedback amplifier, and the use of the cross coupling capacitance of the first stage drain terminal signals respectively coupled to the second stage gate terminal again enlarged, effectively reduce the noise. Cascode structure amplifier is used as the second stage, which makes noise figure and gain of the circuit improved effectively. Simulation results show that the LNA exhibits the input reflection coefficient of-20.6dB, gain of 16.1dB, noise figure of 2.84 dB and the input 1dB compression point of-13.92 dBm.(3)A classic Gilibert active double balanced mixer is designed. The simulation results show that the performance parameters such as noise figure and conversion gain of the mixer are not ideal. So an improved Gilibert active dual balanced mixer is used to improve the performace of the circuit. It improves the circuit noise and conversion gain by using the static current injection and the local oscillator buffer technique, and the buffer of the output is added to enhance the mixer conversion gain and linearity. The simulation results show the Mixer exhibits the noise figure of 12.9dB, conversion gain of 11 dB and the input 1dB compression point of-1.32 dBm.(4)Zero IF receiver architecture is implemented based on the designed circuit module, circuit is constituted by the low noise amplifier and two I/Q branches of mixers, low noise amplifier of RF signal amplification and into I/Q mixer with two inputs, respectively with the local oscillator signal of frequency mixing and finally output 1MHz frequency signal. The simulation results show that the RF front-end delivers 19.14 dB gain with 8.31 dB noise figure,and the input 1dB compression point of 2.37 dBm. It meets the design requirements of RF front-end in 900MHz-RFID receiver.