The Design Of CMOS Up-conversion Mixer

With the rapid development of the wireless communication market,people's demand for highly integrated,high-performance and low-cost RF front-end is becoming increasingly urgent.CMOS process can better realize the integration of analog RF circuit modules and digital circuit modules,which meet the needs of high integration,thereby reducing power consumption and cost.As one of the key circuits of the RF front-end,Mixer's performance will directly affect the overall performance of the RF front-end,in this paper,we will study the mixer used in transmitter.The paper introduces the basic theory of mixer,including the basic principles of mixer,performance parameters and mixer's basic circuit structure and studies the most widely used double-balanced mixer,that is,the Gilbert mixer.By analyzing the circuit structure of the Gilbert mixer,the current injection technology and the source negative feedback technology are proposed and analyzed.Mixer linearity,noise figure,conversion gain improvement,and further provide the knowledge base for mixer circuit design.In this paper,TSMC 65nm CMOS process is used to realize circuit,layout and simulation of harmonic suppression,gain tunable CMOS up-conversion mixer.The simulation results show that the gain of the mixer can be tuned in the range of-12?0dB,the gain step is 6dB,the noise figure is better than 25dB at the highest gain,IIP3 is better than 20dBm,the third harmonic suppression level better than 50dB.