Low Noise Amplifiers and Local Oscillators for Wireless Communications Receivers

摘要

Noise and interference limit the quality of reception of radio signals in caseswhere the useful signal is week. While this holds true in all radio receivers, this thesis focuses more on digital communication receivers. There are a number of distinct types of noise sources in all practical electronic components that radio receivers are made of. There are also great many different mechanisms of how the noise may mask the useful signal before the final detection or the decision making of weather a logic 'zero' or a 'one' was received. Types of interfering signals are also many; they may be in-hand, out-of-band, even co-channel and they may be generated internally or externally. The work behind this thesis introduces new engineering techniques for reducing noise and interference in radio receiver circuits and thereby improving the quality of reception. This thesis starts with a brief introduction to the subject field and the typical associated problems. This is followed by a short description of fixed, mobile, and satellite radio communications systems. Then radio receiver architectures, their main building blocks and their performance parameters are discussed. Basic principles of low noise amplifier and oscillator design are summarized followed by introduction of semiconductor device technologies for these circuits. 60-GHz LNAs were developed using commercially available GaAs/InGaAs PHEMT transistors. The tolerance of bond wire length which could have serious degraded the performance of the design, was compensated off by using a novel technique.