X-Band Broadband MMIC LNA Research

This paper discusses the total design flow of X-band MMIC LNA.The principles of MMIC LNA design,the design of circuit and layout,the EM simulation and test result is introduced.The LNA test result shows that this MMIC LNA is leading in China.The X-band MMIC LNA design based on 0.15μm GaAs Low Noise PHEMT process which provided by WIN semiconductors corp.A structure with three cascaded circuits is used for low noise figure(NF) and high gain.Bias circuits are designed for each stage.Input and output ports are both matched to 50ohm.After each stage achieves design demand,cascade of three-stage circuits proceed optimization.Then design the layout of the circuit and do the EM simulation to optimize the layout.A feedback network is used in the last state to obtain a better gain flatness and enough gain.Source feedback and stable decay structure is used to keep the circuit stability.Optimize the sensitivity of the circuit to obtain a good yield.The X-band broadband MMIC LNA here exhibits a good performance over 8-12GHz,the test results achieves that a typical noise figure is 1.2dB,a gain of over 25dB with flatness of less than±1dB,an input and output VSWR less the 1.5.The results show that it achieves the design demands.