適用於廣頻無線接取系統之互補式金氧半多頻帶射頻前端電路架構設計

支援多頻帶且多系統的收發機由於具有多樣化的功能，提高使用上的便利性，在現今的無線傳輸應用上越來越受到注目。一般而言，實現多頻帶收發器的方式即是使用多組的射頻模組，然而，這種方法增加了電路的複雜度，也提高晶片面積及成本。為了解決這個問題，本論文提出適用於都會型區域網路系統多頻帶射頻接收機的架構，利用電路共用的概念，在2.4 GHz，3.5 GHz及5.2 GHz三個頻帶中，使用一組射頻電路做頻帶切換。在說明這個多頻帶射頻電路前，先介紹低雜訊放大器和混波器的設計考量，及「輪廓圖方法」的設計步驟。根據這個流程，設計且使用CMOS 0.18μm製程實現一個適用於IEEE 802.11a系統的低雜訊放大器。這個低雜訊放大器所占面積為0.6x1.29 mm2，並在1.8 伏特的供給電壓下，消耗功率為5.8毫瓦。接下來介紹本論文所提出的多頻帶射頻前端電路架構，包括一個多頻帶低雜訊放大器，及雙降頻摺疊式混波器。此多頻帶低雜訊放大器採用切換多端點電感的方式達成頻帶的選擇。除了簡省面積外，切換電感可使各頻帶皆有較佳的Q值。此三頻帶低雜訊放大器以CMOS 0.18μm製程實現，面積為1.2x1.5 mm2，不考慮緩衝級下，操作頻率在2.4 GHz時消耗14.6毫瓦，在3.5 GHz和5.2 GHz時消耗24.9毫瓦。整個接收機射頻前端電路以CMOS 0.18μm製程實現，所占面積1.28x1.76 mm2，在1.8伏特電壓下，總消耗功率在2.4 GHz為25.3毫瓦，3.5 GHz為51.2毫瓦，在5.2 GHz為39.2毫瓦。

關鍵字

無線都會區域網路；多頻帶接收機；多頻帶射頻電路；低雜訊放大器

並列摘要

Multi-band and multi-standard transceivers attract more and more attention for their flexibility and functionality. Typically, the transceivers are realized by using two or more sets of RF blocks, which can handle the desired bands. However, this approach may increase chip area, the number of components, and the cost. A way to alleviate these problems is to use one set of RF block which can be tuned for multiple bands. In this thesis, a multi-band receiver architecture, operating at 2.4 GHz, 3.5 GHz and 5.2 GHz, is proposed for IEEE 802.16-2004 sub-11 GHz applications. The receiver RF front-end can achieve maximum hardware sharing while reducing chip area and cost. Before going on the circuits of front-end, the design flows and considerations of RF blocks, i.e. LNA and mixer, are discussed. A technique called “Contour-plot methodology” has been published for LNA design, which can clearly provide designers the relations between design parameters and device size. The design flow of mixer is also presented using the contour-plot technique. Based on this methodology, a 5.2-GHz LNA with fully on-chip matching for WLAN systems is designed and implemented. Using a CMOS 0.18μm process, the LNA occupies an area of 0.6x1.29 mm2 and dissipates 5.8 mW from a 1.8 V power supply. A tri-band LNA for the multi-band receiver RF front-end adopts a inductor-switching technique with a multi-tap inductor to select one of the three desired bands. Inductive switching is superior to capacitive switching since it can achieve better quality factors for each frequency band. Fabricated in CMOS 0.18μm technology, the tri-band LNA has an area of 1.2x1.5 mm2 and dissipates 14.6 mW in 2.4-GHz band and 24.9 mW in 3.5-GHz and 5.2-GHz band without buffer. The proposed mixer uses a dual-conversion folded topology, which is composed of a single-balanced Gilbert-type mixer cascaded by two additional double-balanced PMOS switching pairs. System simulation shows that this topology can alleviate the noise and linearity requirements. The RF front-end occupies an area of 1.28x1.76 mm2 and dissipates 25.3 mW in 2.4 GHz, 51.2 mW in 3.5 GHz and 39.2 mW in 5.2 GHz, respectively.

並列關鍵字

BWA ； 802.16 ； WMAN ； WiMAX ； multi-band receiver ； multi-band RF front-end ； multi-band LNA

參考文獻

[5] Part 16: Air Interface for Fixed Broadband Wireless Access Systems. IEEE Std 802.16-2004, June 2004.

[10] B. Razavi, RF Microelectronics, Prentice-Hall, 1998.

[12] T. Pollet, M. Van Bladel, and M. Moeneclaey, “BER Sensitivity of OFDM Systems to Carrier Frequency Offset and Wiener Phase Noise,” IEEE Trans. Comm., vol. 43, pp. 191-193, Feb./Mar./Apr. 1995.

[14] Jacques C. Rudell, Jia-Jiunn Ou, Thomas Byunghak Cho, George Chien, Francesco Brianti, Jaffrey A. Weldon, Paul R. Gray, “A 1.9-GHz Wide-band IF Double Conversion CMOS Receiver for Cordless Telephone Applications,” IEEE J. Solid-State Circuits, vol. 32, no. 12, pp. 2071-2088, Dec. 1997.

[15] Choa-Shiun Wang, Wei-Chang Li and Chorng-Kuang Wang, “A Multi-band Multi-standard RF Front-end for IEEE 802.16a and IEEE 802.11a/b/g Applications,” in IEEE Int. Symp. on Circuits and Systems (ISCAS’05), May 2005 (accepted).

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適用於廣頻無線接取系統之互補式金氧半多頻帶射頻前端電路架構設計

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