ADS NF<1

xiats

我用ADS仿真LNA，得到的噪声系数居然小于1，请问可能是什么原因？

xiats

电路图

请看一下这个电路，我用ADS仿真得到NF<1，不知是哪出了问题？

goodsilicon

要是小于1dB，也是正常啊。又不是小于0dB.

xiats

回复 3# goodsilicon

谢谢回复，不是1dB, 就是1啦。

严皮皮

噪声系数小于1正常啊，或者你说的是噪声因子小于1？

严皮皮

噪声系数小于1正常啊，或者你说的是噪声因子小于1？

xiats

回复 6# 严皮皮

是NF，ADS的输出nf（2）。真是很奇怪，我想把电路图上载，不知有没有大侠愿意看看，需要TSMC_018_v2的库。

梦飘远方

最后找出来原因了吗？求解答

fangtaocome

Noise Figure
The parameter nf(k) in the dataset is the noise figure at output port k. You can view results using the Data Display. The noise figure for each port will appear in the variables list as nf(1), nf(2), and so on. nf displays noise figures for all ports.

When noise figure is calculated at a port, the other ports in the network are terminated in their respective impedances.

For a 2-port circuit, the noise figure is the signal-to-noise ratio at the input, divided by the signal-to-noise ratio at the output. It has default units of dB. For a circuit with more than two ports, the noise figure is the ratio of the total noise at the output port to the transmitted input noise. The total noise is the transmitted input noise plus the noise contributed by the network. The transmitted input noise represents the portion of the incident thermal noise (kTB, where k=Boltzmann's constant, 1.381...x10-23 J/K, T=290 K, B=1 Hz) which passes through the system.