Research And Design Of Low Power High Linearity Down-conversion Mixer

With the continuous development of the Internet of things technology, wireless communication has become a key technology of the Internet of things technology development. Ultra wideband wireless and Bluetooth wireless communications have fast data transfer, low power consumption and low cost, which have much room for development in the Internet of things technology. The RF receiver is an important function module of a wireless communication system. The mixer is a key part of the RF receiver and its performance directly affect the entire wireless communication system. It is significant to research and design the high-performance mixerThis thesis briefly describes the Internet of things technology and the importance of ultra-wideband wireless and Bluetooth wireless communications in the Internet of things technology, and introduces the research of low-power mixer, high linearity mixer,3.1-10.6GHz ultra-wideband mixer and5.2GHz mixer. Then the thesis does research on the mixer of the RF receiver front-end circuit. According to two performance metrics:low power consumption and high linearity, a3.1to10.6GHz low-power ultra-wideband CMOS down-mixer is proposed which is suitable for the ultra-wideband RF receiver, and5.2GHz high linearity CMOS down-mixer is also proposed which is suitable for the Bluetooth communication system of802.11a standard. The specific work is following:A3.1-10.6GHz ultra-wideband and low-power CMOS mixer is proposed in the thesis. The mixer is optimized based on the Gilbert mixer. The mixer uses current mirror technology, current injection technique and substrate drive technology to reduce the power consumption of the circuit. The linearity of the mixer is optimized by using source inductor feedback technology, and the parallel inductance between the switch and the transconductance stage is for improving the noise performance of the circuit. The simulation results show that the power supply of the down-conversion mixer is only0.8V,power consumption is only2.1mw,conversion gain is10.6-13.5dB, double-sideband noise figure is6.6～12.1dB and linearity is1～8dB.A5.2GHz high linearity CMOS mixer is proposed in the thesis. The mixer adopts current injection technique, current reuse technique and source inductance feedback techniques to improve the linearity. The tail current source is replace by current mirror that reduces the power supply of circuit. Thus the power consumption of the circuit is reduce. It can reduce the influence of parasitic capacitance by using inductance series between the trans-conductance stage and switch level. The simulation results show that the power supply is1.2V,linearity is about27.7dB, the conversion gain is4.7dB, noise figure is7dB and the power consumption is6.7mW.