超宽带SiGe HBT低噪声放大器的设计和分析

摘要

设计了一款具有电阻反馈的新型超宽带(UWB)SiGe HBT低噪声放大器(LNA).因为摒弃了使用占片面积大的电感,所以极大节省了放大器的芯片面积和制作成本.在新型放大器的反馈支路中,使用了复合分布式电阻和隔直流电容,代替了传统的单一电阻.用这种方式设计的LNA,仅通过调整与电容串联的电阻就可以极大地改善放大器的端口匹配,同时不牺牲偏置.最终设计出的LNA版图面积仅为0.144mm2.仿真实验显示,在3.1～10GHz超宽频带内,新型UWB LNA实现了低于4.5dB的噪声系数、高达20dB的增益(增益平坦度仅为1.032dB),小于1.637的输出端驻波比,大于2.3的稳定因子.此研究成果对设计开发低成本、高性能的单片UWB LNA具有重要指导意义.%A novel ultra-wideband (UWB) SiGe HBT low noise amplifier (LNA) with resistive feedback was designed. Due to absence of the inductor which occupies a large chip area, the total die area and the fabrication cost of the amplifier are reduced noticeably. In feedback loops of the novel amplifier, compound distributed resistors and a DC capacitor are used instead of a traditional single resistor. In this way, the output impedance matching of the novel LNA can be improved greatly only by adjusting the resistor that is in series with a capacitor, without sacrificing of biasing conditions. The layout area of the novel resistive feedback LNA is only 0. 144mm2. The simulation results indicate that, in the band of 3.110GHz, the novel UWB LNA achieves the low noise figure (NF) of less than 4.5dB, the gain of as high as 27dB with variation of only 1.032dB, the voltage standing wave radio of less than 1.637 and the stability factor of more than 2.3.The results are of great practical importance, because they provide a guide for the design and development of the low-cost and high performance monolithic UWB LNA.