Derivative-Based Envelope Design Technique for Wideband Envelope Tracking Power Amplifier with Digital Predistortion

doi:10.12142/ZTECOM.2022S1004

ZTE Communications ›› 2022, Vol. 20 ›› Issue (S1): 22-26.DOI: 10.12142/ZTECOM.2022S1004

• Research Paper • Previous Articles Next Articles

Derivative-Based Envelope Design Technique for Wideband Envelope Tracking Power Amplifier with Digital Predistortion

YI Xueya¹, CHEN Jixin¹, CHEN Peng¹, NING Dongfang², YU Chao¹()

^1.State Key Laboratory of Millimeter Waves, Southeast University, Nanjing 210096, China
^2.ZTE Corporation, Shenzhen 518057, China

Online:2022-01-25 Published:2022-03-01
About author:YI Xueya received the B.E. degree in electronic and information engineering from Xidian University, China in 2018. She is currently pursuing the M.E. degree in electromagnetic fields and microwave technology at the State Key Laboratory of Millimeter Waves, Southeast University, China. Her current research interests include bandwidth reduction and shaping of envelope and digital predistortion for wideband envelope tracking power amplifiers.|CHEN Jixin received the B.S. degree in radio engineering from Southeast University, China in 1998, and the M.S. and Ph.D. degrees from Southeast University in 2002 and 2006, respectively, all in electromagnetic field and microwave technique. Since 1998, he has been with the State Key Laboratory of Millimeter Waves, Southeast University. He is currently a professor with the School of Information Science and Engineering and Director of the Department of Electromagnetic Field and Microwave Engineering. His research interests include microwave and millimeter-wave circuit design and monolithic microwave integrated circuit (MMIC) design. Dr. CHEN is the winner of 2016 Keysight Early Career Professor Award and 2016 National Natural Science Prize Second Prize. He has served as TPC Chair of RFIT2019, and TPC Co-Chair of HSIC2012 and UCMMT2012.|CHEN Peng received the B.E. degree in communication engineering and the M.E. degree in electronic engineering from Harbin Institute of Technology, China in 2010 and 2012, respectively, and the Ph.D. degree in electronic engineering from University College Dublin, Ireland in 2016. From 2017 to 2020, he was a research associate with Centre for High Frequency Engineering, Cardiff University, UK. Since 2020, he has been with the State Key Laboratory of Millimeter Waves and is currently a lecturer with the School of Information Science and Engineering, Southeast University, China. His current research interests include the design and optimization of high-efficiency power amplifiers.|NING Dongfang received the M.S. and Ph.D. degrees in control science and engineering from Northwestern Polytechnical University, China in 2016 and 2019. He is currently a senior RF algorithm architect in ZTE Corporation, working in nonlinear system behavioral modeling and linearization for wireless and RF systems.|YU Chao (chao.yu@seu.edu.cn) received the B.E. degree in information engineering, the M.E. degree in electromagnetic fields and microwave technology from Southeast University (SEU), China in 2007 and 2010, respectively, and the Ph.D. degree in electronic engineering from University College Dublin, Ireland in 2014. He is currently a professor with the State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, SEU. His research interest includes microwave and millimeter wave power amplifier modeling and linearization, and 5G massive MIMO RF system design.
Supported by:
the National Natural Science Foundation of China (NSFC)(62022025);the Natural Science Foundation of Jiangsu Province(BK20200065);ZTE Industry-University-Institute Cooperation Funds(HC-CN-20191121016)

Abstract

Abstract:

A novel envelope design for an envelope tracking (ET) power amplifier (PA) based on its derivatives is proposed, which can trade well off between bandwidth reduction and tracking accuracy. This paper theoretically analyzes how to choose an envelope design that can track the original envelope closely and reduce its bandwidth, and then demonstrates an example to validate this idea. The generalized memory polynomial (GMP) model is applied to compensate for the nonlinearity of ET PA with the proposed envelope design. Experiments are carried out on an ET system that is operated with the center frequency of 3.5 GHz and excited by a 20 MHz LTE signal, which show that the proposed envelope design can make a good trade-off between envelope bandwidth and efficiency, and satisfactory linearization performance can be realized.

Key words: bandwidth reduction, envelope tracking, shaping function, supply modulator

YI Xueya, CHEN Jixin, CHEN Peng, NING Dongfang, YU Chao. Derivative-Based Envelope Design Technique for Wideband Envelope Tracking Power Amplifier with Digital Predistortion[J]. ZTE Communications, 2022, 20(S1): 22-26.

Figures/Tables 7

Figure 1 Proposed envelope design with monotonous derivative: (a) envelope design; (b) monotonous derivative

Figure 2 Example of the proposed envelope design: (a) envelope design; (b) derivative of the S function for s=3 and s=10; (c) time domain waveforms; (d) normalized power spectral density of the S envelope

Table 1 Bandwidth and NMSE of the S envelope and traditional envelopes

Parameter	S Envelope				Traditional Envelopes
Parameter	s=3	s=5	s=10	s=16	Wilson	2.ord.PET	N6
BW	1.6×	2.1×	2.6×	3.0×	1.6×	1.6×	3.0×
NMSE/dB	-6.8	-7.0	-7.7	-7.9	-6.6	-6.7	-7.9

Figure 3 Test bench setup

Figure 4 Experiment for validation: (a) plot of samples of the S10 and Wilson envelopes versus the original envelope; (b) normalized power spectrum density of the S10 and Wilson envelopes

Figure 5 Comparison experiment: (a) amplitude-modulation to amplitude-modulation (AM/AM) and amplitude-modulation to phase-modulation (AM/PM) curves; (b) normalized PSD without and with DPD under S10 function; (c) AM/AM and AM/PM curves; (d) normalized PSD without and with DPD under Wilson function

Table 2 Efficiency and nonlinearity performance of the measured ET system

ACLRs/dBc

( $\pm 20 ? M H z$ )

NMSE/dB

ACLRs/dBc

( $\pm 20 ? M H z$ )

Table 2 Efficiency and nonlinearity performance of the measured ET system

Shaping Function

Efficiency/%

Without DPD

With DPD

ACLRs/dBc

( $\pm 20 ? M H z$ )

NMSE/dB

ACLRs/dBc

( $\pm 20 ? M H z$ )

NMSE/dB

S10

43.8

-31.3/-31.6

-21.2

-51.2/-51.8

-38.5

Wilson

-33.3/-33.5

-23.6

-54.0/-54.3

-40.5

References 14

1	GILABERT P L, MONTOTORO G, VEGAS D, et al. Digital predistorters go multidimensional: DPD for concurrent multiband envelope tracking and outphasing power amplifiers [J]. IEEE microwave magazine, 2019, 20(5): 50–61. DOI: 10.1109/mmm.2019.2898021 DOI URL
2	MA J G. RF Front-End Designs of MIMO Systems for 5G and Beyond [J]. ZTE technology journal, 2020, 26(4): 50-576. DOI：10.12142/ZTETJ.202004012 DOI
3	ASBECK P, POPOVIC Z. ET comes of age: envelope tracking for higher-efficiency power amplifiers [J]. IEEE microwave magazine, 2016, 17(3): 16–25. DOI: 10.1109/mmm.2015.2505699 DOI URL
4	WU R L, LI Y, LIE Y C. Design technologies for silicon-based high-efficiency RF power amplifiers: a brief overview [J]. ZTE communications, 2011, 9(3): 28–35
5	KWAN A, YOUNES M, DARRAGI R, et al. On track for efficiency: concurrent multiband envelope-tracking power amplifiers [J]. IEEE microwave magazine, 2016, 17(5): 46–59. DOI: 10.1109/mmm.2016.2525118 DOI URL
6	MONTOTORO G, GILABERT P L, BERTRAN E, et al. A method for real-time generation of slew-rate limited envelopes in envelope tracking transmitters [C]//IEEE International Microwave Workshop Series on RF Front-ends for Software Defined and Cognitive Radio Solutions (IMWS). IEEE, 2010. DOI: 10.1109/IMWS.2010.5441005 DOI URL
7	JEONG J, KIMBALL D F, KWAK M, et al. Wideband envelope tracking power amplifiers with reduced bandwidth power supply waveforms and adaptive Digital predistortion techniques [J]. IEEE transactions on microwave theory and techniques, 2009, 57(12): 3307–3314. DOI: 10.1109/tmtt.2009.2033298 DOI URL
8	YI X Y, CHEN J X, LI H T, et al. Integrated bandwidth reduction and shaping technique for wideband millimeter wave envelope tracking power amplifier with digital predistortion [C]//International Wireless Symposium (IWS). IEEE, 2020. DOI: 10.1109/IWS49314.2020.9360052 DOI URL
9	KWAN A K, YOUNES M, HAMMI O, et al. Linearization of a highly nonlinear envelope tracking power amplifier targeting maximum efficiency [J]. IEEE microwave and wireless components letters, 2017, 27(1): 82–84. DOI: 10.1109/lmwc.2016.2629983 DOI URL
10	HAMMI O, KHALIFA M O, ABDELHAFIZ A, et al. A dual-input two-box model for digital predistortion of envelope tracking power amplifiers [J]. IEEE microwave and wireless components letters, 2016, 23(5): 361–363. DOI: 10.1109/Lmwc.2016.2548984 DOI URL
11	GILOVANNELLI N, VLASITS T,CIDRONALI A, et al. Efficiency and linearity enhancements with envelope shaping control in wideband envelope tracking GaAs PA [C]//International Workshop on Integrated Nonlinear Microwave and Millimetre-Wave Circuits (INMMiC). IEEE, 2011. DOI: 10.1109/INMMIC.2011.5773331 DOI URL
12	WANG Z C. Envelope tracking power amplifiers for wireless communications [M]. London, England: Artech House, 2014: 216–224
13	OLAVSBRATEN M, GECAN D. Bandwidth reduction for supply modulated RF PAs using power envelope tracking [J]. IEEE microwave and wireless components letters, 2017, 27(4): 374–376. DOI: 10.1109/lmwc.2017.2679046 DOI URL
14	MORGAN D R, MA Z X, KIM J, et al. A generalized memory polynomial model for digital predistortion of RF power amplifiers [J]. IEEE transactions on signal processing, 2006, 54(10): 3582–3860. DOI: 10.1109/tsp.2006.879264 DOI URL

Derivative-Based Envelope Design Technique for Wideband Envelope Tracking Power Amplifier with Digital Predistortion

RichHTML

PDF

Knowledge

Abstract

Cite this article

share this article

Figures/Tables 7

References 14

Related Articles 1

Recommended Articles 0

Metrics