L波段线性功率放大器的分析与设计
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摘要
射频功率放大器作为发射机的核心部件,其性能制约了整个通信系统的性能,特别是近年来,无线通信系统向着大容量、多载波、多电平、和高峰均比的方向发展,在此背景下,线性调制技术被广泛的应用,由于这些线性调制技术具有非恒定包络的特点,当调制信号通过射频功率放大器后将产生交调失真,导致已调矢量信号的幅度和相位出现偏差,同时导致频谱扩展,邻道信号受干扰,误码率恶化等。因此,线性射频功率放大器成为研究的热点。
论文围绕L波段线性功率放大器的设计展开,首先分析了功率放大器的基本原理和线性化技术,然后设计了在1.90GHz—2.0GHz频段上基于RF预失真方案的3级功率放大器,并进行了理论分析和性能仿真,仿真测试结果表明该功率放大器具有很好的线性度和较高的输出功率。其中,主要研究内容和有创新的工作表现在以下几个方面:
①通过对功率放大器的理论分析,针对设计需求中功率放大器输出高增益大功率的要求,确定了功率放大器3级级联的设计方案。
②针对功率放大器大信号S参数无法获得的难点,根据各级功率放大器在电路中的作用和工作状态不同,分别用小信号S参数法设计了前置级和驱动级功率放大器,用负载牵引法设计了末级功率放大器。级联后的功率放大器的输出功率34.143dBm、增益大于30dB,带内增益平坦度小于1dB,均高于设计要求。
③为了提高功率放大器的线性度,通过对比各种线性化电路的设计,确定了基于立方律的RF预失真的线性化方案。本文对立方律预失真器进行了改进,采用180°正交电桥替代T型电阻网络并引入平衡电阻网络来修正反向并联二极管对的不对称特性,从而改善了预失真器的性能。另外还设计了3dBWilkinson功率分配/合成器、衰减器和模拟移相器等组件,仿真测试表明,在功率放大器输出35dBm的功率时,加入预失真线性化电路后三阶交调失真(IMD3)小于-60dBc,较预失真前改善了27dBc。该方案有效的改善了功率放大器的线性度。
RF power amplifiers are the hard-core of the transmitter. The performance of the power amplifiers has already restricted the capability of the whole communication system. Especially in recent years, wireless telecommunication system is developing towards adding channel capability, multi-carrier, linear modulation, multi-level, widening the frequency and high PAR. Under the background, linear modulation techniques are widely used. Because linear modulated techniques have the characteristic of varying envelop, modulated signals with varying envelop will generate intermodulation distortion. The distortion results in errors in the magnitude and the phase of the modulated vector signal, enlarging the spectrum, disturbing the adjacent-channel, worsening the error-code-rate and so on. Thereby, linear RF power amplifier has been a hot spot of research.
The dissertation discusses the design of L-band linear power amplifier. First of all, it analyses the principle of power amplifier and linearization techniques. Secondly, the RF predistortion linear three stages power amplifier that work in the 1.90GHz—2.0GHz band is designed. The amplifier is simulated to test its performance. The simulation results demonstrate that the amplifier has a good linearity and high output power.
The main contents and innovation of the dissertation are as follow:
①Through analyzing the theory of power amplifier, the design scheme of three stages amplifiers cascade is confirmed, in order to meet high output power and great gain of the power amplifier.
②Because of unavailable large signal S parameters and different operating state& performance among the amplifiers, pre-stage and driver stage amplifiers are designed by the method of small signal S parameters, while last stage amplifier by load-pull design method. The cascade amplifier has 34.143dBm output power, greater than 30dB gain, and less than 1dB gain flatness. All of these performances are superior to design index.
③In order to improve the linearity of the amplifier, the plan based on the cubic law predistortion is confirmed by comparing lots of linearization techniques. And the innovative improve of the cubic law predistorter include: 1) Using the 1800 quadrature coupler instead of T-type resistance network. 2) Inserting balance resistance network to correct the asymmetry of the antiparallel diode pair. It great improves the predistorter performances. At the same time, 3dB Wilkinson power dividers/combiners, attenuator and analog phase shifter are also designed. The result shows that, when the output power of the amplifier is 35dBm, the IMD3 can be less than -60dBc by the effect of the predistortion system. The predistortion system can improve IM3 27dBc. It improves the power amplifier linearity effectively.
论文围绕L波段线性功率放大器的设计展开,首先分析了功率放大器的基本原理和线性化技术,然后设计了在1.90GHz—2.0GHz频段上基于RF预失真方案的3级功率放大器,并进行了理论分析和性能仿真,仿真测试结果表明该功率放大器具有很好的线性度和较高的输出功率。其中,主要研究内容和有创新的工作表现在以下几个方面:
①通过对功率放大器的理论分析,针对设计需求中功率放大器输出高增益大功率的要求,确定了功率放大器3级级联的设计方案。
②针对功率放大器大信号S参数无法获得的难点,根据各级功率放大器在电路中的作用和工作状态不同,分别用小信号S参数法设计了前置级和驱动级功率放大器,用负载牵引法设计了末级功率放大器。级联后的功率放大器的输出功率34.143dBm、增益大于30dB,带内增益平坦度小于1dB,均高于设计要求。
③为了提高功率放大器的线性度,通过对比各种线性化电路的设计,确定了基于立方律的RF预失真的线性化方案。本文对立方律预失真器进行了改进,采用180°正交电桥替代T型电阻网络并引入平衡电阻网络来修正反向并联二极管对的不对称特性,从而改善了预失真器的性能。另外还设计了3dBWilkinson功率分配/合成器、衰减器和模拟移相器等组件,仿真测试表明,在功率放大器输出35dBm的功率时,加入预失真线性化电路后三阶交调失真(IMD3)小于-60dBc,较预失真前改善了27dBc。该方案有效的改善了功率放大器的线性度。
RF power amplifiers are the hard-core of the transmitter. The performance of the power amplifiers has already restricted the capability of the whole communication system. Especially in recent years, wireless telecommunication system is developing towards adding channel capability, multi-carrier, linear modulation, multi-level, widening the frequency and high PAR. Under the background, linear modulation techniques are widely used. Because linear modulated techniques have the characteristic of varying envelop, modulated signals with varying envelop will generate intermodulation distortion. The distortion results in errors in the magnitude and the phase of the modulated vector signal, enlarging the spectrum, disturbing the adjacent-channel, worsening the error-code-rate and so on. Thereby, linear RF power amplifier has been a hot spot of research.
The dissertation discusses the design of L-band linear power amplifier. First of all, it analyses the principle of power amplifier and linearization techniques. Secondly, the RF predistortion linear three stages power amplifier that work in the 1.90GHz—2.0GHz band is designed. The amplifier is simulated to test its performance. The simulation results demonstrate that the amplifier has a good linearity and high output power.
The main contents and innovation of the dissertation are as follow:
①Through analyzing the theory of power amplifier, the design scheme of three stages amplifiers cascade is confirmed, in order to meet high output power and great gain of the power amplifier.
②Because of unavailable large signal S parameters and different operating state& performance among the amplifiers, pre-stage and driver stage amplifiers are designed by the method of small signal S parameters, while last stage amplifier by load-pull design method. The cascade amplifier has 34.143dBm output power, greater than 30dB gain, and less than 1dB gain flatness. All of these performances are superior to design index.
③In order to improve the linearity of the amplifier, the plan based on the cubic law predistortion is confirmed by comparing lots of linearization techniques. And the innovative improve of the cubic law predistorter include: 1) Using the 1800 quadrature coupler instead of T-type resistance network. 2) Inserting balance resistance network to correct the asymmetry of the antiparallel diode pair. It great improves the predistorter performances. At the same time, 3dB Wilkinson power dividers/combiners, attenuator and analog phase shifter are also designed. The result shows that, when the output power of the amplifier is 35dBm, the IMD3 can be less than -60dBc by the effect of the predistortion system. The predistortion system can improve IM3 27dBc. It improves the power amplifier linearity effectively.
引文
[1] Antes T, Conkling C. RF chip set fits multimode cellular/PCS handsets[J]. Microwave RF, 1996: 177-186.
[2]亢树军,马云霞,刘伦才.一种高线性SiGe HBT宽带低噪声放大器[J].微电子学报, 2006, 36(5): 1-4.
[3] Molavi R, Mirabbasi S, Hashemi M. A wideband CMOS LNA design approach[J]. IEEE Transactions on Circuits and Systems, 2005, 5: 5107-5110.
[4] Andrei G.射频与微波功率放大器设计[M].张玉兴译.北京:电子工业出版社, 2006.
[5] Gray P R, Hurst P J, Lewis S H.模拟集成电路的分析与设计,第四版[M].北京:高等教育出版社, 2005.
[6]戈稳.雷达接收机技术[M].北京:电子工业出版社, 2005.
[7] Ulrich L R, David P N. RF/Microwave Circuit Design for Wireless Applications [M]. New York: John Wiley&Sons Inc, 2000: 923-924.
[8] Steve C C. RF Power Amplifiers for Wireless Communications[M]. Boston: ARTECH HOUSE Inc, 1999.
[9]宋利艳. 2GHz线性功率放大器的分析与设计[D].南京:南京理工大学, 2008.
[10] Curtice W R, Ettenberg M. A nonlinear GaAs FET model for use in the design of output circuits for power amplifier[J]. IEEE MTT, 1985, 33(12): 1384-1394.
[11] Kacprzak T, Materka A. Computer calculation of large-signal GaAs FET amplifier characteristics[J]. IEEE Trans MTT, 1985, 33(2): 129-135.
[12]袁孝康,王仕,王番等.微带功率晶体管放大器[M].北京:人民邮电出版社, 1982.
[13] Gonzalez G.微波晶体管放大器分析与设计[M].白晓东译. (第2版).北京:清华大学出版社, 2003: 185-330.
[14] David M P.微波工程[M].张肇仪,周乐柱,吴德明等译. (第3版).北京:电子工业出版社, 2006: 461-491.
[15]郑建彬,孟庆鼐,魏启辅.微波功率放大器的小信号S参数设计方法[J].合肥工业大学学报, 2005, 11(6): 17-20.
[16] Peter A, Jaime P, Daren B, et al. A wideband method for the rigorous low-impedance loadpull measurement of high-power transistors suitable for large-signal model validation[J]. IEEE Microwave Magazine, 2005, 4(10): 78-82.
[17] Griffin E L. Application of landline simulation to microwave high power amplifiers[J]. IEEE Microwave Magazine, 2000, 6(1): 58-66.
[18] Andriy V V, Peter W, Winfried B, et al. 17-GHz 50–60 mW power amplifiers in 0.13-um standard CMOS [J]. IEEE Microwave and Wireless Components Letters, 2006, 16(1).
[19] Yue T, Mahender K, Johnny K O, et al. A 900-MHz fully integrated SOI power amplifier for single-chip wireless transceiver applications [J]. IEEE Journal of Solid-State Circuits, 2000, 35(10).
[20]孙玲.高效率射频功率放大器线性化技术的比较研究[J].南通工学院学报(自然科学版), 2002, 1(3): 32-34.
[21]张玉兴.射频模拟电路[M].北京:电子工业出版社, 2003.
[22]陈邦媛.射频通信电路[M].北京:科学出版社, 2002.
[23] Stewart R D. Feed-forward linearization of 950MHz amplifiers[J]. IEEE Proeeedings, . 1988,135(10): 347-350.
[24]欧阳溢波.通信系统中功率放大器和低噪声放大器的研制[D].成都:电子科技大学,2006.
[25]艾渤,杨知行,潘长勇.高功率放大器线性化技术研究[J].微波学报, 2007, 23(l): 62-70.
[26]王伟旭,张玉兴.射频功放的立方预失真线性化技术[J].无线电工程, 2006, 36(9):44-45.
[27]石海霞.射频功率放大器的线性化一预失真线性化器的研究[D].成都:电子科技大学,2005.
[28]姚恺.射频功率放大器的线性化技术研究[D].成都:西南交通大学, 2006.
[29]李宏斌,刘辉,官伯然.一种模拟预失真线性化射频放大器[J].杭州电子工业学报, 2004, 24(6): 8-11.
[30]黄谋辉.射频功率放大器的研究与设计[D].北京:北京邮电大学, 2007.
[31] Thomas L C. Eliminating Broadband Distortion in Transistor Amplifiers[J]. Bell System Technical Journal, 1968:315-342.
[32] Katz A, Sudarsanam R, Aubert D. Reflective Diode Linearizer for Spacecaraft Applications[J]. IEEE MTT-S International Microwave Symposium Digest, 1985: 661-664.
[33] Wei Huang, Ricardo E. S. Novel Third-Order Distortion Generator with Residual IM2 Suppression Capabilities [J]. IEEE.Transactions On Microwave Thoery and Techniques, 1998,12(46):2372-2382.
[34]林强,张祖荫,郭伟.微波功率放大器非线性失真分析[J].微波学报, 2004, 20(4).
[35] Yi J, Yang Y, Park M, et al. Analog Predistortion Linearizer for High Power RF Amplifier[J]. IEEE MTT-S International Microwave Symposium Digest, 2003: 1511-1514.
[36] Stewart R D, Tusubira F F. Predistortion Linearisantion of Amplifiers for UHF Mobile Radio[J]. Conference Proceedings-European Microwave Conference, 1988: 1017-1022.
[2]亢树军,马云霞,刘伦才.一种高线性SiGe HBT宽带低噪声放大器[J].微电子学报, 2006, 36(5): 1-4.
[3] Molavi R, Mirabbasi S, Hashemi M. A wideband CMOS LNA design approach[J]. IEEE Transactions on Circuits and Systems, 2005, 5: 5107-5110.
[4] Andrei G.射频与微波功率放大器设计[M].张玉兴译.北京:电子工业出版社, 2006.
[5] Gray P R, Hurst P J, Lewis S H.模拟集成电路的分析与设计,第四版[M].北京:高等教育出版社, 2005.
[6]戈稳.雷达接收机技术[M].北京:电子工业出版社, 2005.
[7] Ulrich L R, David P N. RF/Microwave Circuit Design for Wireless Applications [M]. New York: John Wiley&Sons Inc, 2000: 923-924.
[8] Steve C C. RF Power Amplifiers for Wireless Communications[M]. Boston: ARTECH HOUSE Inc, 1999.
[9]宋利艳. 2GHz线性功率放大器的分析与设计[D].南京:南京理工大学, 2008.
[10] Curtice W R, Ettenberg M. A nonlinear GaAs FET model for use in the design of output circuits for power amplifier[J]. IEEE MTT, 1985, 33(12): 1384-1394.
[11] Kacprzak T, Materka A. Computer calculation of large-signal GaAs FET amplifier characteristics[J]. IEEE Trans MTT, 1985, 33(2): 129-135.
[12]袁孝康,王仕,王番等.微带功率晶体管放大器[M].北京:人民邮电出版社, 1982.
[13] Gonzalez G.微波晶体管放大器分析与设计[M].白晓东译. (第2版).北京:清华大学出版社, 2003: 185-330.
[14] David M P.微波工程[M].张肇仪,周乐柱,吴德明等译. (第3版).北京:电子工业出版社, 2006: 461-491.
[15]郑建彬,孟庆鼐,魏启辅.微波功率放大器的小信号S参数设计方法[J].合肥工业大学学报, 2005, 11(6): 17-20.
[16] Peter A, Jaime P, Daren B, et al. A wideband method for the rigorous low-impedance loadpull measurement of high-power transistors suitable for large-signal model validation[J]. IEEE Microwave Magazine, 2005, 4(10): 78-82.
[17] Griffin E L. Application of landline simulation to microwave high power amplifiers[J]. IEEE Microwave Magazine, 2000, 6(1): 58-66.
[18] Andriy V V, Peter W, Winfried B, et al. 17-GHz 50–60 mW power amplifiers in 0.13-um standard CMOS [J]. IEEE Microwave and Wireless Components Letters, 2006, 16(1).
[19] Yue T, Mahender K, Johnny K O, et al. A 900-MHz fully integrated SOI power amplifier for single-chip wireless transceiver applications [J]. IEEE Journal of Solid-State Circuits, 2000, 35(10).
[20]孙玲.高效率射频功率放大器线性化技术的比较研究[J].南通工学院学报(自然科学版), 2002, 1(3): 32-34.
[21]张玉兴.射频模拟电路[M].北京:电子工业出版社, 2003.
[22]陈邦媛.射频通信电路[M].北京:科学出版社, 2002.
[23] Stewart R D. Feed-forward linearization of 950MHz amplifiers[J]. IEEE Proeeedings, . 1988,135(10): 347-350.
[24]欧阳溢波.通信系统中功率放大器和低噪声放大器的研制[D].成都:电子科技大学,2006.
[25]艾渤,杨知行,潘长勇.高功率放大器线性化技术研究[J].微波学报, 2007, 23(l): 62-70.
[26]王伟旭,张玉兴.射频功放的立方预失真线性化技术[J].无线电工程, 2006, 36(9):44-45.
[27]石海霞.射频功率放大器的线性化一预失真线性化器的研究[D].成都:电子科技大学,2005.
[28]姚恺.射频功率放大器的线性化技术研究[D].成都:西南交通大学, 2006.
[29]李宏斌,刘辉,官伯然.一种模拟预失真线性化射频放大器[J].杭州电子工业学报, 2004, 24(6): 8-11.
[30]黄谋辉.射频功率放大器的研究与设计[D].北京:北京邮电大学, 2007.
[31] Thomas L C. Eliminating Broadband Distortion in Transistor Amplifiers[J]. Bell System Technical Journal, 1968:315-342.
[32] Katz A, Sudarsanam R, Aubert D. Reflective Diode Linearizer for Spacecaraft Applications[J]. IEEE MTT-S International Microwave Symposium Digest, 1985: 661-664.
[33] Wei Huang, Ricardo E. S. Novel Third-Order Distortion Generator with Residual IM2 Suppression Capabilities [J]. IEEE.Transactions On Microwave Thoery and Techniques, 1998,12(46):2372-2382.
[34]林强,张祖荫,郭伟.微波功率放大器非线性失真分析[J].微波学报, 2004, 20(4).
[35] Yi J, Yang Y, Park M, et al. Analog Predistortion Linearizer for High Power RF Amplifier[J]. IEEE MTT-S International Microwave Symposium Digest, 2003: 1511-1514.
[36] Stewart R D, Tusubira F F. Predistortion Linearisantion of Amplifiers for UHF Mobile Radio[J]. Conference Proceedings-European Microwave Conference, 1988: 1017-1022.