Design and Implementation of Low Noise Amplifiers and Distributed Amplifiers

• Main Authors: Mu-Tsung Lai, 賴木聰
• Other Authors: 曹恆偉
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/93676376242758027042

碩士 === 國立臺灣大學 === 電子工程學研究所 === 96 === In the receiving path, low noise amplifier (LNA) is a very important building block at the front end of the communication system. Because the received signal is amplified through LNA, which is behind the antenna, it dominates the noise figure (NF) and input voltage standing-wave ratio (VSWR) of the overall system. On the other hand, wideband amplifiers are widely used in high-speed optical communication systems, microwave/millimeter-wave communications, sensor systems, or wideband instruments. Distributed amplifiers (DA) provide very high gain-bandwidth products, together with lower input and output return losses for broadband applications. This thesis is divided into three parts. First, some fundamental concepts of UWB wireless communication systems and wideband circuit techniques are introduced. Second, the design and performance of a K-band LNA using standard CMOS process is presented. Finally, two distributed amplifiers are described. Some important fundamental theories of UWB wireless communication and wideband circuit techniques are reviewed. Some essential circuit performance specifications are also introduced. Also presented in this thesis is the design of a K-band LNA using a modified folded cascade structure that achieved a measured gain of 12.4 dB at 34.76 GHz with associated power consumption of 74.8mW. Finally, two broadband amplifiers are implemented using distributed circuit techniques. A 3.2~6.57 GHz DA architecture with a modified folded cascade gain stage achieves a measured gain of 12.6 dB. Another DA with gain-enhancement in its gain stage achieves a simulated 23 dB gain with a bandwidth of 41.7 GHz bandwidth and power consumption of 136 mW.