文档介绍：Chapter 2
Low-Noise Amplifiers in CMOS Wireless
Receivers
Introduction
This chapter aims to e the reader to the world of low-noise amplification in wireless
receivers. The most important RF concepts are introduced in Section . These concepts include
the quality factor of reactive elements, different types of matching, power gain and distortion.
Topics that will return and gain significance in various discussions further on.
Section introduces the device models that will be used in hand calculations. Hand cal-
culations will be applied throughout the text to give intuitive insight in the behavior of different
circuits and circuit aspects. The models have been fit in advance to numerical simulation results.
Also an extended MOS model is introduced that has been used in conjunction with the numerical
simulators. The mon noise sources in CMOS IC’s are discussed together with their
physical origin in Section . In Section , the LNA is described in its function and func-
tionality within the receiver chain. The coherence and mutual dependence of the LNA with the
other receiver blocks is investigated. Based on that, the main design criteria and performance
requirements are derived.
To conclude this chapter, the mon LNA topologies in CMOS are classified and in-
troduced with a simple —but not irrelevant— performance model in Section . Already a swift
comparison can be made. Some specific and interesting designs, published in open literature but
falling beyond theabove classification are clarifiedbriefly.
Some Important RF Concepts
Quality Factor of Reactive Elements and Series-Parallel Transfor-
mation
A few concepts that will ur often are the resonance, quality factor and series-parallel trans-
formation of reactive elements. For a purely reactive element the current through the element is
10 Low-Noise Amplifiers in CMOS Wireless Receivers
90 degrees out of phase with the voltage over it. Hence no power is consumed in the el