Design Of Anti-interference Low-noise Amplifier Applied To Satellite Navigation System

In recent years,the satellite navigation system has become a rapidly developing international high-tech industry,which has been used in many fields such as military and civilian fields.When the satellite navigation system works in an extreme electromagnetic environment,it is inevitably interfered by various electromagnetic signals.The low-noise amplifier is the first active module of the navigation receiver,whose function is to amplify the weak signal from the antenna and to suppress the noise effect of the circuit module in the next stage.Considering that the receiver cannot use external shielding structure,studying the anti-electromagnetic interference of low-noise amplifier has become an urgent issue.This thesis first introduces the performance indicators of low-noise amplifiers,analyzes the three basic structures of low-noise amplifiers,and summarizes the advantages and disadvantages of the each circuit structure.The second part of the work briefly introduced satellite navigation receivers working in extreme electromagnetic environments,analyzed the types of interference signals,summarized the existing methods for improving electromagnetic compatibility performance,and proposed the interference signal modeling used in this article which is verified the preliminary results following.The next step is circuit design.The performance indicators and the overall circuit structure are determined firstly.After calculation and preliminary simulation,the confirmed values of the component parameters are obtained and the performance indicators of the low-noise amplifier are simulated and analyzed to verify meeting the design specification.The final step is the interference signal quatification,simulation and analyzation for the interference signal impaction on the performance indicators of the low noise amplifier adding the interference signal source,and finally the layout of the low noise amplifier is designed.Based on the TSMC 0.18?m CMOS process,this thesis completed the simulation for the performance index of the low noise amplifier in Cadence.The simulation results show that when the operating frequency is 1.575GHz,the gain S₂₁is 24.36d B,the noise factor NF is 2.02d B,the input and output reflection coefficients are-11.31d B and-12.75d B,1d B compression point and third-order intermodulation point are-17.794d Bm and-15.672d Bm,linearity meets the design specification.The simulation adding the interference signal shows that the interference signal has an impact on the noise,gain and linearity of the amplifier,and the noise performance and linearity has the most severely affection.The area of the layout for this low-noise amplifier is 267*211?m².