Research On The Nonlinear Effects Of High-power Microwaves On Radar Receivers

The electromagnetic environment becoming more and more complex,epecially the emergence of high power microwave and other strong electromagnetic pulse environment,makes the electronic devices more vulnerable.In order to prevent various microwave pulses from affecting electronic equipments,high power microwave effect research is needed.High power microwave can directly act on the RF front end of the radar receiver and poses a threat to the radar system.Therefore,the study of high power microwave nonlinearity in radar receiver system can provide a basis for the protection and reinforcement of radar system.In this paper,the common radar receivers are investigated and classified,and the typical and universal super heterodyne radar receiver is selected as the research object.The microwave coupling channel of radar receiver is analyzed,the PIN limiter,which is the first device to receive strong EMI pulses in the coupling channel,and the most vulnerable device LNA,are selected as the key research objects of device-level high power microwave nonlinear effect,and their characteristic parameters are introduced.The method of device modeling is compared.The equivalent circuit models for PIN limiter and LNA are established,which are suitable for the study of high power microwave effect.The numerical simulation results are consistent with the experimental results.The effect pulse broadening of PIN limiter increases with the increase of injection pulse width and power.The broadening of the LNA effect pulse increases with the increase of the injection pulse power,but there is no obvious rule with the change of the injection pulse width.According to the results of simulation and experiment,the mechanism of the effect is simply analyzed.According to the results of high power microwave nonlinearity effects of devices and components,the experiments of high power microwave effects on typical receivers are carried out,and the experimental results of the system are analyzed.The experiment-tal results of system-level effects are in good agreement with the results of non-linear effects of devices and components.The paper studies the effect of high-power microwave from device to system step by step,obtains some effect laws,gives some reasonable mechanism explanations,identify the weakness of the circuit,and provides some references for the reinforcement and protection research of radar system.