Low-noise performance of SiGe heterojunction bipolar transistors

We have demonstrated, for the first time, a microwave noise figure below 1 dB at 10 GHz from a heterojunction bipolar transistor. The current and frequency dependence of the results obtained agree with the well-established Hawkins theory for bipolar transistor noise performance. An enhanced equivalent noise circuit including major parasitics provides valuable insight for the optimization of these devices for low-noise operation. Typical applications may include integrated RF front-ends where low-noise amplification is desired in addition to low phase-noise oscillation and mixing which typically benefit from bipolar devices.<
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