Design Of A K-band Low Noise Amplifier Based On CMOS Technology

K-band low noise amplifier is the key active amplification module of satellite communication RF receiving system.It is one of the hotspots of the next generation wireless communication technology.The noise performance of low noise amplifier will directly affect the signal-to-noise ratio of the whole receiving link,so the low noise requirement is a difficulty in the design of low noise amplifier.Therefore,maintaining a sufficiently high gain in the working frequency band is another difficulty of the low noise amplifier.Facing the application characteristics and index requirements of the next generation wireless communication technology,this paper studies the K-band low noise amplifier from the aspects of process devices,noise model,circuit structure and layout design.The main work and innovations of this paper are as follows:（1）This paper systematically studies the performance of passive devices in 65nm CMOS process,focuses on the design factors of inductance and balun,and puts forward the design scheme of inductance,capacitance,balun and other passive devices suitable for this subject from the perspective of Q value and coupling coefficient.（2）The traditional structure and innovative structure of low noise amplifier are introduced and analyzed.It is found that the capacitive cross coupling structure has obvious advantages in improving gain and reducing noise figure.（3）A new low noise amplifier structure is proposed,that is,a low noise amplifier is designed by using two-stage capacitor cross coupling cascade and balun as inter stage matching.By selecting appropriate MOS tube size,bias voltage and matching circuit,low noise,high gain and good linearity are realized.Based on the above research,a broadband low noise amplifier chip for K-band communication based on 65nm GP CMOS process is designed in this paper.The simulated working frequency band of the LNA chip is 19.4GHz～21.4GHz,the actual working frequency band is 17GHz～19GHz,In the passband,S₁₁≤-12dB,S₂₂≤-11dB,NF≤3.18dB,the maximum gain is 20dB,IP1dB≥-23dBm,and the area of the layout is 790μm×470μm.