Noise and Linearity Improvement Techniques for CMOS RF Front-end

• Main Authors: Shih-Chieh Chou, 周士傑
• Other Authors: Po-Chiun Huang
• Format: Others
• Language: en_US
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/82338836439704824027

碩士 === 國立清華大學 === 電機工程學系 === 96 === This research works on the circuit development with noise and linearity improvement for wideband RF front-end circuits. The driving vehicle is mobile TV standards, such as DVB-H system at UHF band from 470 to 890MHz. This system presents many technical challenges especially low noise and high linearity over wide bandwidth. The power consumption is of great concern due to the limited battery capacity for handheld receivers, and the use of low cost CMOS is desirable. In this research three different circuits are developed. First is a LNA with multiple gain setting and noise cancellation. With the wideband nature of shunt feedback structure, the input matching over a wide bandwidth can be sustained. Second is a LNA with a new noise reduction strategy. Instead of using feedforward cancellation, this work uses a feedback topology for noise suppression. With the signal-nulling feature, the linearity constraint of feedforward cancellation technique can be broken. Third is the noise and linearity improvement for wideband LNA and mixer integration. The proposed circuit configuration can apply both feedforward noise cancellation and multi-gate distortion cancellation. With the breakthrough of the tradeoff between power consumption and linearity, a good noise and linearity performance can be obtained under decent power dissipation for a front-end design. These techniques developed in this research can be applied to different front-end circuit topologies to achieve a better noise and linearity performance.