Miniaturized Low Noise Amplifier Development Of Beidou S-band Receiver

The low noise amplifier(LNA)is a key component of the receiver,which can be widely used in electronic countermeasure,radar detection,microwave communication and satellite navigation etc.The performance of the LNA is of great importance on reducing noises and improving communication quality.With the popularization of handheld devices,users propose more strict requirements on the size of products,requiring the LNA to be developed in the orientation of miniaturization and low voltage.The LNA researched and developed in this paper works in Beidou S-band,where the center frequency is 2491.75MHz;bandwidth is 8 MHz;working voltage is 3.3V;working electric current is less than 40 mA and the size is 58mm×30mm×10mm.This project adopts theoretical analysis combined with simulations to discuss toward the LNA.The LNA is designed from aspects such as selection of amplification circuit forms,design of matching circuit,structural selection of biasing circuit and stability analysis etc.Advanced Design System(ADS)is utilized to conduct simulation of schematic circuit diagrams and analyze problems of the LNA such as transmission gain,VSWR,noise figure and stability etc.Protel is utilized to design PCB diagram.Finally,the layout design of S-band LNA and a series of circuit processing and debugging are completed;the LNA applied for Beidou S-band receiving system is developed.The achieved indicators are: transmission gain at 39±2dB,noise figure less than 1.5dB,input VSWR less than 1.5 and output VSWR less than 2.0.The testing result indicates that the developed LNA satisfies the requirements of indicators,conforms to the market requirements and is suitable for mass production.