SiGe heterojunction bipolar transistors—The noise perspective
| Autor: | Hermann Schumacher, Wolfgang Durr, U. Erben |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Noise temperature
Materials science business.industry Noise spectral density Electrical engineering Y-factor Condensed Matter Physics Noise figure Low-noise amplifier Electronic Optical and Magnetic Materials Noise generator Hardware_INTEGRATEDCIRCUITS Materials Chemistry Optoelectronics Effective input noise temperature Flicker noise Electrical and Electronic Engineering business |
| Zdroj: | Solid-State Electronics. 41:1485-1492 |
| ISSN: | 0038-1101 |
| Popis: | Si/SiGe heterojunction transistors with high germanium concentration in the base layer are capable of microwave noise figures below 1 dB at X-band frequencies, because of their low base resistance. We review critical device parameters which influence the minimum noise figure, location of the noise-optimum source reflection coefficient, and associated gain at noise match, including both low-parasitic double-mesa and highly manufacturable box-shaped HBT devices in our considerations. A higher associated gain can be obtained when the base-collector feedback capacitance is reduced. Using larger transistors, both the magnitude of the noise-optimum source reflection coefficient and the equivalent noise resistance will be reduced, making input matching easier and less lossy. Low-frequency noise results show 1/ f corner frequencies below 1 kHz in microwave devices. Two circuit examples, a d.c.-18 GHz amplifier and a low-noise active antenna at 5.8 GHz, demonstrate that device capabilities can be translated into superior circuit performance. |
| Databáze: | OpenAIRE |
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