近年來，通訊頻帶寬度變得越來越窄，這意味著改善頻帶寬度的效率是必須的。為了增加分配給特定系統的頻率寬範圍的效率，迫使的現今的無線系統的數位調設計變得更複雜、更高階，導致對系統上的線性度要求越來越嚴苛。由於功率放大器通常為非線性的，這也成為在頻寬及無線功率放大器之間的主要問題，然而藉由使用各種不同的線性化技術，我們將可以改善高效率功率放大器的線性度。
在本篇論文裡面所著重的是在使用蕭特基二極體來做預失真線性化。也對一些普遍在使用的預失真技術做了介紹，除此之外也對用來表示非線性特性的方法做了簡短的討論，如雙音分析測試。也很詳細的討論二極體預失真線性器的運作過程，結果也展示出在頻率為1.8GHz 及 1.9GHz藉由蕭特基二極體預失真器所改善的交互調變失真。

Recently, communications channels are becoming increasingly crowded, which presents the need for improved bandwidth efficiency. In order to make more efficient use of the frequency spectrum analyzer(E4445A) allocated for a particular system, there is a push towards complex higher order digital modulation schemes in modern radio systems, resulting in stricter linearity requirements on the system. Since power efficient amplifiers are typically nonlinear, this poses a major problem in realizing a bandwidth and power efficient radio system. However, by employing various linearization techniques, the linearity of a high efficiency PA may be improved.
The work presented in this thesis focuses on schottky diode predistortion linearization. Background discussion on common linearization techniques available to the PA designer is presented. In addition, a discussion of methods of nonlinearity characterization is presented, for example, the use of two-tone analysis. The operation of diode predistortion linearizers is discussed in detail. Results show an improvement in intermodulation distortion ratio (IMD) due to the schottky diode predistorter in both 1.8GHz and 1.9GHz cases.

[1] Cripps, S., RF Power Amplifiers for Wireless Communications, Boston: Artech House, 1999.

[2] Rappaport, T. S., Wireless Communications, New Jersey: Prentice-Hall, 1996.

[3] Kenington, P.B., “Methods Linearize RF Transmitters and Power Amps (Part 1),” Microwaves & RF, vol. 37, no. 13, December 1998, pp. 102-116.

[4] Kenington, P.B., “Methods Linearize RF Transmitters and Power Amps (Part 2),” Microwaves & RF, vol. 38, no. 1, January 1999, pp. 79-89.

[5] Raab, F. H., Sigmon, B. E., Myers, R. G., and Jackson, R. M., “High-Efficiency L-Band Kahn-Technique Transmitter,” IEEE MTT-S Digest, May 1998, pp. 585-588.

[6] Takahashi, M., Asari, N., and Aihara, S., “A Negative Feedback Amplifier in Microwave Frequencies,” NEC Research and Development, no. 77, April 1985, pp.63-69.

[7] Moazzam, M. R. and Aitchison, C. S., “A Low Third Order Intermodulation Amplifier with Harmonic Feedback Circuitry,” IEEE MTT-S Digest, June 1996, pp. 827-830.

[8] Jing, D., Chan, W. S., Li, S. M., and Li, C. W., “New Linearization Method Using Interstage
Second Harmonic Enhancement,” IEEE Microwave and Guided Letters, vol. 8, no. 11, November 1998, pp. 402-404.

[9] PST Inc., “High Power Feed Forward Amplification Systems,” Microwave Journal, Feb. 1994, pp. 128-133.

[10] Eid, E., Ghannouchi, F. M., and Beauregard, F., “Optimal Feedforward Linearization
System Design,” Microwave Journal, November 1995, pp.78-86.

[11] Cox, D.C., “Linear amplification with nonlinear components,” IEEE Transactions on. Communications, vol. COM-22, Dec. 1974, pp. 1942-1945.

[12] Bateman, A., “The combined analogue locked loop universal modulator (CALLUM),” Proceedings of the 42nd IEEE Vehicular Technology Conference, May 1992, pp.759-763.

[13] Imai, N., Nojima, T., and Murase, T., “Novel Linearizer Using Balanced Circulators and Its Application to Multilevel Digital Radio Systems,” IEEE Transactions on MTT, vol. 37, no. 8, 1989, pp. 1237-1243.

[14] Zhang, W-M. and Yuen, C., “A Broadband Linearizer for Ka-Band Satellite Communication,” IEEE MTT-S Digest, May 1998, pp. 1203-1206.

[15] Yamauchi, K., et al., “A Novel Series Diode Linearizer for Mobile Radio Power
Amplifiers,” IEEE MTT-S Digest, June 1996, pp. 831-834.

[16] J. C. Pedro and N. B. Carvalho, Intermodulation Distortion Microwave and
Wireless Circuits, Artech House, Norwood, MA, 2003.

[17] F. H. Raab, et al., RF New and Microwave Power amplifier and Transmitter
Technologies, May, 2003.

[18] D. K. Chen, Field and Wave Electromagnetics, Addison-Wesley, 1989.

[19] G. Gonzalez, Microwave Transistor Amplifiers Analysis and Design.
Prentice-hall, Upper Saddle River, New Jersey: 1997.

[20] K. Yamauchi, K. Mori, M. Nakayama, Y. Mitsui, and T. Tadashi, A microwave miniatured linearizer using a parallel diode with a bias feed resistance, IEEE Trans Microwave Theory Tech MTT-45 (1997), 2431–2435.

[21] Yamakuchi, K., et al., A Novel Series Diode Linearizer for Mobile Radio Power Amplifier,” Proc. IEEE Intl. Microw. Symp., MTT-S 1996, San Francisco, CA, WE3F-6, pp. 831–834.

[22] Katz, A, et al., “Passive FET MMIC Linearizers for C, X, Ku-Band Satellite Applications,” Proc. IEEE Intl. Microw. Symp., MTT-S 1993, Atlanta, GA, WE3F-6, pp. 353–356.

[23] Kumar, M., et al., Predistortion Linearizer Using GaAs Dual-Gate MESFET for TWTA and SSPA Used in Satellite Transponders, IEEE Trans. on Microwave Theory and Technology, MTT-33, No. 12, 1985, pp. 1479–1499.

[24] Y. T. Kao, “Broad-Band Power Amplifier Design Using Equal-Length Lines and z-domain Technique,” National Taiwan University of Science and Technology, Taipei, Taiwan (2008)

[25] J. Voulevi, T. Rahkonen, and J. Manninen, “Measurement technique for characterizing memory effects in RF power amplifiers,” IEEE Trans. Microwave Theory Tech., vol. 49, pp. 1383–1389, Aug. 2001.

[26] Steve C. Cripps, Advanced Techniques in RF Power Amplifier Design, Boston: Artech House, INC., 2002

[27] Zhan Xu, MacEachern, L., “A Predistortion Circuit Design Technique for High Performance Analogue Optical Transmission,” Microsystems and Nanoelectronics Research Conference, 2008. MNRC 2008. 1st, pp. 213-216,Oct. 2008

[28] R. Neil Braithwaite“Low Cost, Low Delay UMTS Power Amplifier usinig Digital-Controlled Adaptive Analog Predistortion,” Microwave Conference, 2006. 36th Eruopean, pp. 1641-1644, Sept. 2006.

[29] Y.S Lee, M.W Lee, S.H Kam, Y.H Jeong, “Advanced design of high-linearity analog predistortion Doherty amplifiers using spectrum analysis for WCDMA applications,”Radio and Wireless Symposium (RWS), 2010 IEEE, 2010, pp. 140-143.

[30] R. Neil Braithwaite, Scott Carichner, and Matthew J.Hunton, “Data ACquistion for digital-Controlled Adaptive Analog Predistortion of a Power Amplifier,” Radio and Wireless Symposium, 2007 IEEE, pp. 411-414, Jan. 2007.

[31] Yi Liao, DongLin Su, Yi Wang, Wenqing Chen, “A Design of Analog Predistortion Linearizer for RF Power Amplifier to Reduce IMD,” Antennas, Propagetion and EM Theory, 2008, ISAPE 2008. 8th International Symposium on, pp.1154-1157, Nov. 2008