中文摘要：

对SiGe HBT的高频噪声进行了模拟。频率f、载流子正向延迟时间τF、集电极电流等因素都对高频噪声有影响。当频率高于高频转角频率时，最小噪声系数NFmin随着频率的增大而线性增大，而不是与f^2成正比关系，且NFmin随着集电极电流的增大先减小后增大。结果表明，噪声最小时的最佳偏置电流所对应的特征频率fT并不是最大特征频率，约为最大特征频率的50％。

英文摘要：

High frequency noise characteristics of SiGe HBTs were simulated. Many factors, such as frequency, carrier forward delay time τF and collector current, have influence on high frequency noise characteristics. When the frequency was higher than high-frequency comer frequency, the minimum noise figure NFmin was directly proportional to f but not f^2 ; NFmin decreased at low collector current and then increased as the collector current increases. Result from simulation shows optimum collector current of minimum noise figure is not the maximum fT,