传一篇关于LNA设计的文章

l21035

【文件名】:06714@52RD_Small-Signal-Amplifier-Design-and-Measurement.pdf
【格　式】:pdf
【大　小】:2406K
【简　介】:
【目　录】:



So far device models and the parameter sets have been presented. It is now
important to develop the major building blocks of modern RF circuits and this
chapter will cover amplifier design. The amplifier is usually required to provide
low noise gain with low distortion at both small and large signal levels. It should
also be stable, i.e. not generate unwanted spurious signals, and the performance
should remain constant with time.
A further requirement is that the amplifier should provide good reverse
isolation to prevent, for example, LO breakthrough from re-radiating via the aerial.
The input and output match are also important when, for example, filters are used
as these require accurate terminations to offer the correct performance. If the
amplifier is being connected directly to the aerial it may be minimum noise that is
required and therefore the match may not be so critical. It is usually the case that
minimum noise and optimum match do not occur at the same point and a circuit
technique for achieving low noise and optimum match simultaneously will be
described.
For an amplifier we therefore require:
1. Maximum/specified gain through correct matching and feedback.
2. Low noise.
3. Low distortion.
4. Stable operation.
5. Filtering of unwanted signals.
6. Time independent operation through accurate and stable biasing which
takes into account device to device variation and drift effects caused by
variations in temperature and ageing.
It has been mentioned that parameter manipulation is a great aid to circuit
design and in this chapter we will concentrate on the use of y and S parameters for
amplifier design. Both will therefore be described.