超寬頻 CMOS 低雜訊放大器

近年來，自從美國聯邦電信委員會(FCC)將頻譜上 3.1GHz 到 10.6GHz 的頻段分配給 UWB無線通訊系統後，UWB 無線系統的發展受到學術界與工業界的高度關注。UWB 系統是一種低耗電、高傳輸速率的無線通訊技術，其應用領域很廣，包括影像系統、穿透牆壁或地面的雷達顯像、追蹤與監視裝置、以及商業上與家庭娛樂的無線高速傳輸系統等等。而位在 UWB 接收系統的第一級電路，就是低雜訊放大器，由於低雜訊放大器是接收系統的第一級，所以在操作頻率範圍內必須具有很小的雜訊指數(大約3dB)並且要提供夠大的增益(大約20dB)，而如何設計一個適用在 UWB 無線系統的寬頻低雜訊放大器，則成為了一個新的挑戰。本論文主要研究如何設計具有寬頻操作的低雜訊放大器，並且使用UMC 0.18um CMOS 製程，實現此一超寬頻(UWB)積體低雜訊放大器。本論文之寬頻低雜訊放大器使用網路合成的設計理論，藉由設計帶通濾波器來實現寬頻匹配網路。並利用增益補償理論，設計中間級匹配電路，補償電晶體隨頻率上升而下降的增益，以維持寬頻放大器的增益平坦度。最後，結合了負回授技術實現一個 3.0-7.5 GHz 的超寬頻低雜訊放大器積體電路。電路操作在 1.8V 偏壓，功率消耗為 32mW，從 3.1GHz 到 7.5 GHz，放大器量測的雜訊指數皆小於 3.8 dB，而增益為 19dB。

關鍵字

寬頻低雜訊放大器；網路合成；增益補償理論；負回授

並列摘要

Ultra-wideband (UWB) radio is a new wireless technology that can be used for high-speed data transmission at low cost with relative power. One of the most critical components in an UWB radio system is the front-end low-noise amplifier (LNA) because it needs to provide low noise figure (~3 dB) and high gain (~20 dB) over a very broad frequency range. It is a new and difficult challenge to design an usable broadband low- noise amplifier for UWB transceiver. This thesis presents the systematic design approaches to realizing a low-noise amplifier over a wide operation frequency range. The resistor shunt-feedback is used to constitute the broadband matching conditions for both noise and gain performance. The network synthesis is an approach of realizing broadband matching network by designing a bandpass filter. The gain compensation technique is applied on the interstage network to provide compensation for the gain roll-off of the active devices. A fully-integrated 3.0-7.5 GHz UWB low-noise amplifier is implemented using UMC 0.18μm CMOS technology. The measured noise figure is lower than 3.8 dB from 3.1 to 7.5 GHz. Operated on a 1.8V supply, the LNA delivers 19dB power gain and dissipates 32mW of power.

並列關鍵字

Broadband LNA ； Network Synthesis ； Gain compensation theory ； Feedback

參考文獻

[1] A. Ismail and A. Abidi, “A 3-10-GHz Low-Noise Amplifier With Wideband LC-Ladder Matching Network,” IEEE J. Solid-State Circuit, vol. 39, no. 12, pp. 2269-2277, Dec. 2004.

[2] A. Bevilacqua and A. M. Niknejad, “An Ultrawideband CMOS Low-Noise Amplifier for 3.1-10.6-GHz Wireless Receivers,” IEEE J. Solid-State Circuit, vol. 39, no. 12, pp. 2259-2268, Dec. 2004.

[3] D. T. Mellor and J. G. Linvill, “Synthesis of Interstage Network of Prescribed Gain Versus Frequency Slopes,” IEEE Trans. Microwave Theory Tech., vol. 23, no. 12, pp. 1013-1020, Dec. 1975.

[4] R.-C. Liu, et al., “A 0.6-22GHz Broadband CMOS Distributed Amplifier,” IEEE RFIC Symp. Dig., pp. 103-106, Jun. 2003.

[5] C.-W. Kim et al., “An Ultra-wideband CMOS Low Noise Amplifier for 3-5-GHz UWB System,” IEEE J. Solid-State Circuit, vol. 40, no. 2, pp. 544-547, Feb. 2005.

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超寬頻 CMOS 低雜訊放大器

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