| Space and Groud Integrated Information Network is a major project listed in the Outline of the 13th Five-Year Plan and the 13th Five-Year Plan for National Scientific and Technological Innovation.It can realize regional high capacity communication,high reliable and safe communication.In the broadband communication system based on this background,the noise performance and working bandwidth of low noise amplifier have a crucial impact on the sensitivity and signal transmission rate of the whole RF receiving front-end.In order to ensure its stability and reliability in space,the low noise amplifier needs to maintain good performance at room temperature and extreme low temperature.Therefore,in-depth research on low noise amplifiers that can work in ultra-wide bands,different temperatures and have a small noise figure has important significance and application value for the development of space science.SiGe Heterojunction Bipolar Transistor(SiGe HBT)has become an ideal choice for broadband and wide temperature range low noise amplifier because of its excellent frequency,noise and gain characteristics under wide temperature conditions.Because the lowest applicable temperature of commercial device model is 218K,the noise model of SiGe HBT device at 77K～218K is studied in this thesis to guide the low-temperature simulation of wideband low noise amplifier.Aiming at the problem that the traditional SPICE model ignores the correlation of shot noise,an improved SiGe HBT low temperature noise model is proposed in this thesis.The transition time is introduced to characterize the correlation of shot noise.The comprehensive simulation results and test results show that the improved noise model can significantly improve the fitting accuracy of noise parameters at low temperature.Based on the commercial room temperature device model and the improved low temperature noise model of SiGe HBT,a broadband and wide temperature range low noise amplifier that can work in 6～30GHz is designed in this thesis.The amplifier is a three stage amplifier structure,in which the first stage adopts a common emitter structure.Aiming at the disadvantages of the traditional emitter inductor negative feedback structure in broadband application,an improved Miller Capacitor Broadband Matching Technology is innovatively proposed in this paper.The technology is realized by the Miller capacitance of SiGe HBT in the common emission amplification stage,the first stage load is incorporated into the input matching network for design.It realizes broadband input matching and have good low noise performance.The latter two stages are cascode structures using parallel peaking technology to improve broadband gain flatness.The overall chip area is only 0.88mm~2.The joint simulation results show that the gain of the low noise amplifier can reach up to 23.5d B in the frequency range of6～30GHz and temperature conditions of 77K,218K and 300K,and the in-band gain flatness is less than±1.9d B.The noise figure is less than 2.66d B,which can be as low as 1.4d B at 77K.The reflection coefficient of the input and output ports is less than-10d B,the DC power consumption of the circuit does not exceed 38.7m W.The broadband quality factor(Fo M)of this low-noise amplifier is higher than 10,indicating that the amplifier has excellent comprehensive performance and can be applied to radio frequency receiving systems,which can work in broadband and wide temperature range. |
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