Research On Characteristics Of An S-band Crossed Field Amplifier

Crossed field amplifier(CFA)is a vacuum electronic device that uses electrons to move in mutually perpendicular electric and magnetic fields and exchange energy with a microwave field to amplify the signal.It is developed on the basis of magnetrons.It has the advantages of small size,low operating voltage,stable phase,high efficiency,wide bandwidth,etc.Amplifier products have a large number of applications,and are widely used in radar systems such as target search and tracking.CFA have an irreplaceable role in many microwave tubes.This article mainly conducts basic theoretical analysis and simulation research on the S-band crossed field amplifier.Theoretical research mainly includes the movement of electrons in the crossed field amplifier in the static field and the high-frequency field the dispersion characteristics of the slow wave structure and the coupling impedance.In the simulation study,in order to ensure the accuracy of the results,different software was used to model and analyze the slow-wave structure,input-output structure and the whole tube of the crossed field amplifier.The simulation study firstly determines the slow wave structure,and selects the short tube support zigzag line as the slow wave structure.In order to make the slow wave structure meet the design requirements,the dispersion characteristics and coupling impedance of the slow wave structure are analyzed,and the slow wave structure is studied.The effect of size parameters on high frequency characteristics.The second is to analyze the transmission characteristics.First,the CST software is used to build the model,select a simple coaxial structure as the input and output structure,adjust the connection between the input and output structure and the slow wave structure to achieve good coupling,and finally make the standing wave ratio less than 1.65,and the energy transmission effect obtained from the S parameter is good.In order to verify the accuracy,the CHIPIC software is used to perform a cold simulation on the whole tube structure.From the input and output power diagrams,it can be seen that the signal transmission effect is good.Through the simulation of the cold state by two kinds of software,the correctness of the model establishment and meshing is determined,which lays the foundation for the thermal state analysis.Based on the success of cold simulation,CHIPIC and CST electromagnetic simulation software were used to conduct particle simulation research on S-band crossed field amplifier.Firstly,the overall model was established,and the anode and cathode spacing and end caps were analyzed and optimized.Secondly,study the state under the zero input signal.When there is no signal input,noise will be generated.When there is an appropriate signal input,the noise can be effectively suppressed.Finally,two kinds of electromagnetic simulation software are used to conduct particle simulation research on the entire crossed field amplifier.CHIPIC simulation software results show that when the working voltage is 18.3kV and the magnetic field strength is 0.175 T,the gain reaches more than 13 dB in the 2.66-2.95 GHz band,the spectrum is pure,the output power reaches the maximum at 2.83 GHz,the gain is 14.2dB,and the electronic efficiency 60%.CST simulation results show that under the same working conditions,the gain is greater than 13 dB in the 2.66-2.95 GHz band,the output power is maximum at the frequency point of 2.83 GHz,the gain is 14.9dB,the electronic efficiency is 62%,and the signal-to-noise ratio is greater than 40 dB,which meets According to the requirements of the control system.