X-band Radio Frequency Receiving Front-end Design

The project background is based on the wide application of the current X band radar receiver.Due to the characteristics of its band and the current development of radio frequency technology,the application of X band radar is diversified.The application system,broadcast satellite,fixed satellite communications business,earth exploration satellite,meteorological satellite applications in satellite;in military applications,application of X band radar(X Band is Radar,abbreviated as XBR),including the fire control,target tracking radar.The receiver is the main function of the signal received by the antenna such as limiting amplitude,frequency conversion,filtering,amplifying and demodulation processing,at the same time,the receiver must stray signals to external interference and internal noise signal to suppress the signal as much as possible to keep the amount of information and pure as much as possible,so as to the signal for the next step of data processing.The receiver consists of RF circuit,control circuit and digital circuit components,RF front-end receiver module is the most important component,determines the main indicators of noise coefficient,the receiver dynamic range of the receiver.In this thesis,we need to design a RF front component for X band radar receiver.In the design process,a method of adding an isolator at the input of the component is proposed to increase the input reverse isolation.This design method makes the input VSWR of the component reach 1.5.In the process of gain allocation,the design method of RF gain and intermediate frequency gain is adopted.When the component meets the gain index,it improves the noise figure index better.The components were assembled after the completion of the project,and the reliability of the components was verified under different test conditions.The final design met the reliability requirements.Finally,the test results of the X band RF front design meet the requirements.The gain test results meet the requirements of 21 ±1dB index,the noise index is less than 5dB,VSWR is less than 1.5,the output of P-1 is larger than 16dBm,the test results satisfy requirements.The low noise design of the component can provide a pure signal ratio for the whole radar,and the higher gain can provide high sensitivity for receiving system.The output P-1 and the gain level guarantee the linear dynamic level of the reception.The product has experienced several environmental screening tests to ensure the application of the product in every bad environment.Airborne,vehicular,shipboard,adaptable to different use requirements,cold and tropical,components can work normally at different ambient temperatures.The reliability of the product is improved,and the prospect of application is quite wide.