Design And Implementation Of Microwave Transistor Low Noise Amplifier

Microwave low-noise amplifier (LNA) is a key component of front-end of receiver, which is widely used in microwave communication, radar, electronic countermeasure and every kind of Precision microwave measurement system. It is essential to develop LNA with excellent performance because its performance has a direct impact on the performance of the entire receiving system.This paper mainly studies the design and implementation of the low-noise amplifier. First of all the article introduces the design theory of LNA, which is composed of the analysis of microwave transistors, the technical indicators of LNA and electromagnetic compatibility (EMC) design consideration. And then the design of LNA is simulated and optimized using Advanced Design System (ADS) which is provided by Agilent Company.Firstly a LNA working from 4.4GHz to 5.0GHz is designed. It achieves the two-stage structure according to gain requirenment. First-class is matched with best noise figure and the second level is designed with MMIC low noise block which has high gain taking the noise into account. The layout is designed by AutoCAD based on the guidelines of the general RF PCB board design. The accuracy of layout design is verified through the co-simulation of schematic and momentum by ADS. The measured performance meets to the design requirements. In addition, a LNA working from 1.7GHz to 2.0GHz is designed. A source negative feedback inductance is used to enhance the stability of amplifier in this design. LC components are used for match networks. Because of having the strong distribution effect in the high frequency the high frequency equivalent circuits of lumped elements are analyzed. The accuracy of the simulation is greatly increased when it is simulated by using the actual model of lumped elements. Test results meet the design specifications.The paper studies the design of the broadband LNA. The performance and the structural characteristics of the several common broadband technologies are analysed and compared. Balance and negative feedback are used to design 3.5~5.5GHz and 0.2~1.3GHz LNA respectively. The test performance is good.