毫米波發射器線性化及十億位元無線通信系統

Millimeter-wave Transmitter Linearization and Gigabit Wireless Communication Systems

蔡政翰(Jeng-Han Tsai)

指導教授 ： 黃天偉

共同指導教授 ： 王暉(Huei Wang)

國立臺灣大學/電機資訊學院/電信工程學研究所/博士(2007年)

https://doi.org/10.6342/NTU.2007.01844

摘要

本論文研究方向是著重於研究毫米波發射器線性化及毫米波十億位元(Gigabits)無線通信系統。
隨著無線通信系統的快速發展，微波頻帶已趨近於飽和，為了能有更寬的頻譜來達成更快的傳輸速率，寬頻的毫米波無線通信系統將被需要，為了有效率的使用頻譜，現今的無線通訊系統多採用複雜的數位調變技術，期望在有限的頻譜內達到更快的傳輸速率，而這些使用數位調變技術的無線通訊系統對發射器的線性度要求非常高，加上在毫米波頻段，功率放大器每增加1dBm線性輸出功率所花費的代價是很大的，因此再此論文的第一部份我們研究了功率放大器的線性化技術，並提出了一毫米波單晶積體電路低損耗內建式的線性器架構，此線性器可以提升功率放大器的線性輸出功率，並且有低損耗，小體積，低複雜度，零功率消耗的優點，這些優點讓此線性器適合毫米波的應用。為了驗證此線性器，我們將此線性器整合到毫米波功率放大器中來達成前置失真線性化，經過前置失真線性化的放大器線性度有顯著改進，頻譜成長可以改善8 dB，線性輸出功率最高可提升3 dBm，這是首次在毫米波單晶積體電路中實現線性化的技術，此外我們設計一毫米波40 GHz至48 GHz寬頻次諧波發射器晶片，此晶片整合了一個的次諧波混頻器、一個具有濾波特姓的緩衝放大器、和一個內建式的線性器，此線性器應用在毫米波發射器中，可達成後置失真線性化，提升整各毫米波發射器的線性度，另外我們提出了在多核帝放大器中整合後置失真線性化系統，由於多核帝放大器與後置失真系統架構相似，因此我們可以在不增加面積下，同時提升毫米波功率放大器的線性度與效率。
接下來我們介紹毫米波十億位元無線通信系統，我們將設計的晶片組裝成毫米波無線收發模組，做發射與接收系統測試，並完成了毫米波收發系統展示平台。但是為了毫米波消費市場的需求，這些系統需要高效能，高整合度，低功率消耗，低成本的電路設計，因此我們用互補式金氧半導體(CMOS)製程設計了適用在直接轉換(direct-conversion)收發系統中的次諧波調變器與解調器，次諧波混頻的技術可以改善在直接轉換收發系統中，本地振盪洩漏的問題，另外為了在毫米波產生四相位的本地震盪訊號，我們在CMOS製程中設計一振盪訊號四相位分波器，接下來為了寬頻的需要，此次諧波調變器與解調器中的混頻器採用了低品質因素(Q)值的設計，最後量侧結果此次諧波調變器與解調器可以有大於十億位元的調變與解調能力。

關鍵字

線性化 ； 毫米波 ； 功率放大器 ； 發射器 ； 十億位元

並列摘要

The purpose of this dissertation is to develop millimeter-wave transmitter linearization and wireless Gigabit communication systems.
As the demands for wireless communication technology are growing rapidly recently, the microwave frequency bands have been saturated with various communication applications. For high-capacity and high-speed wireless data transmission, the communication channel needs larger bandwidth. Therefore millimeter-wave frequency bands are the solution for high data rate communication system, even wireless Gigabit applications. To enhance the spectral efficiency, modern wireless communication systems tend to use complex digital modulation schemes. These communication systems require a high-linearity MMW transmitter to minimize the spectral re-growth and maintain modulation accuracy. However linear output power of the power amplifier is an expensive resource. Therefore, in this dissertation we proposed a low-loss built-in linearizer using a shunt cold-mode HEMT. The linearizer has advantages of low insertion loss, compact die-size, and zero dc consumption and suitable for MMW linearization applications. To demonstrate the function of the linearizer, MMW power amplifier with built-in linearizaer for pre-distortion linearization has been presented. After linearization, the linearity of the power amplifier has been improved and the spectrum re-growth can be suppressed by 8 dB. For the same linearity requirements, the linear output power of the MMW power amplifier has been doubled. To the best of our knowledge, this is the first MMW power amplifier with a low-loss built-in linearizer. In addition, a MMW 40-48 GHz broadband sub-harmonic transmitter has been presented. The transmitter consists of a sub-harmonic mixer, a band-pass driver amplifier, and a built-in linearizer. The linearizer with post-distortion characteristic can enhance the linearity of the whole transmitter. Furthermore, a MMW Doherty amplifier with post-distortion linearization is presented. The topology of the Doherty amplifier is similar to a post-distortion system. Therefore we can improve the linearity and efficiency of the amplifier simultaneously without increasing the chip area.
Follow are the introduction of the MMW Gigabit wireless communication systems. For MMW system demonstration, the MMW MMIC chips were assembled to transmitter and receiver modules. The experimental results show the transmitter and receiver modules have been applied to MMW point-to-point communication system successfully. However, for MMW marketplace requirement, not only fabricating a chipset with high performance but also size and cost reductions in the transceiver are important issue. Therefore sub-harmonic modulator and demodulator are designed and fabricated using standard CMOS process for MMW direct-conversion transceiver in this dissertation. The main problem, LO leakage, can be improved by using sub-harmonically pumped mixing technique. A MMW four-way quadrature divider using 90° coupler and 180° balun have been implemented in the CMOS process to provide equal amplitude and quadrature-phases LO signals for sub-harmonically pumped modulator and demodulator. For broadband sub-harmonic modulator and demodulator designs, the low quality factor impedance matching network is design and analysis. Finally the experimental results show the sub-harmonic modulator and demodulator MMIC feature Gigabit modulation and demodulation quality for MMW wireless Gigabit direct-conversion applications.

並列關鍵字

Linearization ； Millimeter-wave ； Power amplifier ； Transmitter ； Gigabit

參考文獻

[2] A. Nordbotten, "LMDS Systems and their application," IEEE Communication Magazine, pp. 150-154, June 2000.

[3] D. Hayter; K. Yard, “40 GHZ MVDS parameters and planning standards [multipoint video distribution systems MVDS: The Way Forward,” IEE Colloquium on, 7 Apr. 1992, pp. 2/1-2/6.

[4] Y. Shoji, C.-S. Choi, and H. Ogawa, “70-GHz-band OFDM transceivers based on self-Heterodyne scheme for millimeter-wave wireless personal area network,” IEEE Trans. Microw. Theory Tech., vol. 54, no. 10, pp. 3664-3674, Oct. 2006.

[8] H. Ogawa, “Millimeter-wave wireless personal area network systems,” in Proc. Radio Frequency Integrated Circuits Symp. (RFIC 2006), June 2006, pp. 11-13.

[10] S. T. Choi, K. S. Yang, S. Nishi, S. Shimizu, K. Tokuda, and Y. H. Kim, “A 60-GHz point-to-multipoint millimeter-wave fiber-radio communication system,” IEEE Trans. Microw. Theory Tech., vol. 54, no. 5, pp. 1953-1960, May 2006.