A Two stage x-band low noise amplifier optimized for minimum noise application

Low Noise Amplifiers (LNA) are used as the first stage of any radio frequency receiver or any sensitive application requiring detection of very small signals with the minimum possible additional noise in order to get maximum signal-to-noise ratio at the output which also provide large enough gain to supersede the noise added by the following stages. An X-Band two stage low noise amplifier operating in the 8.2-8.4 GHz frequency band with active bias network by using microstrip technology is studied. The first stage of the LNA is designed to minimize the noise figure and the second stage of the amplifier is designed to obtain the necessary gain. The input match is optimized for better noise figure and to obtain reasonable input coupling. Total gain is kept above a certain value in order not to degrade the total noise figure of the whole cascaded system. Stability is obtained without sacrificing the in-band gain. Agilent’s ADS tool is used to simulate and Altium Designer tool is used for PCB design. The measurement results are compared with simulation results and the comparison shows good agreement.