| Low noise amplifier is an important part of microwave radio systems, it is generally in the front end of the whole communication system,its main role is to communication signals received by the antenna amplifying, signal processing of r elated modulation communication system to facilitate the back. The noise coefficient size directly affects the reliability and system sensitivity of the receiving system.This paper expounds the basic theory of the amplifier, using Advanced Design System software to design a low noise device; its topology circuit is balanced. The main technical indexes of working frequency: 6GHz-12GHz; gain is greater than or equal to 25dB; the noise is less than or equal to 2.5dB less than or equal to 1.5; in Bobbi. This paper mainly includes the following contents:The first chapter introduces the development trend of communication system,expounds the significance of low noise amplifier on communication system, and describes the application and Prospect of low noise amplifier. And introduces the development trend of microwave circuit CAD.The second chapter describes the basic index of microwave circuit two port network theory and low noise amplifier and the corresponding physical significane. Introduces the design process and analysis method of microwave circuit CAD main content features and design process and ADS software.The third chapter expounds the design method of low noise amplifier steps ofbroad band, determine the choice of balanced amplifier circuit as the form of the graduation design of low noise amplifier.The fourth chapter of the whole circuit design of low noise amplifier using Advanced Design System software, a detailed analysis of each design process, finally get the various indicators have reached the requirements of the balanced low noise amplifier.The fifth chapter for the actual demand of the project is encountered, through the preparation of auxiliary software to solve the induction windingin ductance value calculation problems and gate source feedback resistan cecalculation problem.The sixth chapter on this topic make work summary. |
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