摘要
从异质结晶体管(HBT)的小信号模型着手,得到了几种不同反馈形式下HBT的S参数解析表达式。通过对比不同反馈形式的仿真结果,分析了各种反馈形式对S参数的影响,并着重研究了反馈技术对电路稳定性以及对超宽带低噪声放大器(UWB LNA)增益平坦度的影响。结果表明,采用串联电阻和电感或并联电阻和电容的电抗性负反馈,可以使S21的幅度随着频率的增大而逐渐上升,从而补偿了晶体管本身高频增益的下降,同时,也提高了整个电路的稳定性。采用这种反馈结构,设计了一款3～10 GHz超宽带低噪声放大器。仿真结果表明,该放大器在整个频带范围内无条件稳定,传输增益较高,增益平坦度较好,噪声系数较低,是一款无条件稳定并有着较好增益平坦度的超宽带低噪声放大器。
Based on small signal models of hetero-junction bipolar transistors（HBTs） with different feedback circuits,the expressions for S parameters of the device were derived to analyze the influence of different feedback technologies on the amplifier performance,especially on the stability and the gain flatness of the ultra-wideband low noise amplifier（UWB LNA）.When the serial resistor and inductor or the parallel resistor and capacitor are added into the feedback circuits to induce the reactive feedback,the amplitude of S21 increases gradually as the frequency increases,the HBT inherent gain decreasing in high frequency is compensated,and a good stability performance can also be reached simultaneously.With the feedback structure,a 3-10 GHz UWB LNA was designed.The simulation results show that throughout the whole frequency band,the amplifier remains unconditionally stable and has a high transmission gain,good gain flatness and low noise figure.
出处
《半导体技术》
CAS
CSCD
北大核心
2011年第3期218-222,共5页
Semiconductor Technology
基金
国家自然科学基金项目(60776051
61006059
61006044)
北京市自然科学基金项目(4082007)
北京市教委科技发展计划项目(KM200710005015
KM200910005001)
北京市优秀跨世纪人才基金项目(67002013200301)
模拟集成电路国家重点实验室基金项目(51439010804QT0101)
北京市属市管高等学校人才强教计划资助项目
