Hostname: page-component-78c5997874-8bhkd Total loading time: 0 Render date: 2024-11-10T12:26:06.509Z Has data issue: false hasContentIssue false
  • English
  • Français

Implementation of dynamic bias and digital predistortion to enhance efficiency and linearity in a 100 W RF amplifier with OFDM signal

Published online by Cambridge University Press:  22 June 2009

Ludovic Bacque ,
Gregoire Nanfack-Nkondem ,
Philippe Bouysse ,
Guillaume Neveux ,
Jean Michel Nebus ,
William Rebernak ,
Luc Lapierre ,
Denis Barataud  and
Raymond Quéré
Ludovic Bacque
Affiliation:
XLIM – CNRS IUT GEII, 7 rue Jules Valles, 19100 Brive la Gaillarde, France.
Gregoire Nanfack-Nkondem
Affiliation:
XLIM – CNRS 123, Avenue Albert Thomas, 87060 Limoges Cedex, France.
Philippe Bouysse*
Affiliation:
XLIM – CNRS IUT GEII, 7 rue Jules Valles, 19100 Brive la Gaillarde, France.
Guillaume Neveux
Affiliation:
XLIM – CNRS 123, Avenue Albert Thomas, 87060 Limoges Cedex, France.
Jean Michel Nebus
Affiliation:
XLIM – CNRS 123, Avenue Albert Thomas, 87060 Limoges Cedex, France.
William Rebernak
Affiliation:
THALES Communications – 160 Boulevard de Valmy, 92704 Colombes, France.
Luc Lapierre
Affiliation:
CNES Toulouse – 18 Avenue Edouard Belin, 31055 Toulouse, France.
Denis Barataud
Affiliation:
XLIM – CNRS 123, Avenue Albert Thomas, 87060 Limoges Cedex, France.
Raymond Quéré
Affiliation:
XLIM – CNRS IUT GEII, 7 rue Jules Valles, 19100 Brive la Gaillarde, France.
*
Corresponding author: P. Bouysse Email: philippe.bouysse@xlim.fr
Get access Rights & Permissions [Opens in a new window]

Abstract

This paper presents a technique that enables both efficiency and linearity enhancements of power amplifiers (PA) used in communication systems. It consists in the implementation of a dynamic bias control combined with digital base-band predistortion. The aim of this paper is to describe a methodology and successive steps of the design procedure to reach optimum performances in terms of power added efficiency (PAE) and linearity. It is here applied to a 100 W wide-band lateral diffused metal oxide semiconductor (LDMOS) push–pull amplifier (50–500 MHz) driven by orthogonal frequency division multiplexing (OFDM) signals. When the amplifier is driven by a continuous wave (CW) signal and operates at a constant 28 V drain bias voltage, it exhibits 100 W output power and 60% PAE. When it is driven by an OFDM signal, a 10 dB output power back-off is necessary to have a −25 dBc adjacent channel power ratio (ACPR) and PAE decreases down to 10%. By properly implementing an envelope tracking bias system, 40 W output power along with 38% PAE and −27 dBc ACPR have been reached. Applying base-band digital predistortion provides additional linearity improvements at high PAE (for only one point PAE lost, a 5 dB improvement is obtained for ACPR).

Keywords

Smart power amplifierEnvelop trackingPower added efficiencyLinearityDigital predistortion
Type
Original Article
Information
International Journal of Microwave and Wireless Technologies , Volume 1 , Special Issue 4: European Microwave Week 2008 , August 2009 , pp. 261 - 268
Copyright
Copyright © Cambridge University Press and the European Microwave Association 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

[1]Nam, J.; Kim, B.: The Doherty power amplifier with on-chip dynamic bias control circuit for handset application. IEEE Trans. Microwave Theory Tech., 55 (2007), 633–642.CrossRefGoogle Scholar
[2]Moon, J.; Kim, J.; Kim, I.; Kim, B.: A wideband envelope tracking Doherty amplifier for WiMAX systems. IEEE Microwave Wirel. Compon. Lett., 18 (2008), 49–51.CrossRefGoogle Scholar
[3]Raab, F.H.; Rupp, D.J.: High-efficiency single-sideband HF/VHF transmitter based upon envelope elimination and restoration, in Proc. Sixth Int. Conf. HF Radio Systems and Techniques (HF '94) (IEE CP 392), York, UK, 4–7 July 1994, 21–25.CrossRefGoogle Scholar
[4]Kimball, D.F. et al. : High-efficiency envelope-tracking W-CDMA base-station amplifier using GaN HFETs. IEEE Trans. Microwave Theory Tech., 54 (2006), 3848–3856.CrossRefGoogle Scholar
[5]Forestier, S.; Bouysse, P.; Quere, R.; Mallet, A.; Nebus, J.M.; Lapierre, L.: Joint optimization of the power added efficiency and the error-vector measurement of 20 GHz PHEMT amplifier through a new dynamic bias-control method. IEEE Trans. Microwave Theory Tech., 52 (2002), 1132–1141.CrossRefGoogle Scholar
[6]Wang, N.; Yousefzadeh, V.; Makasimovic, D.; Pajic, S.; Popovic, Z.B.: 60% efficient 10-GHz power amplifier with dynamic drain bias control. IEEE Trans. Microwave Theory Tech., 52 (2004), 1077–1081.CrossRefGoogle Scholar
[7]Deng, J.; Gudem, P.; Larson, L.E.; Kimball, D.; Asbeck, P.M.: A SiGe PA with dual dynamic bias control and memoryless digital predistortion for WCDMA handset applications, in Radio Frequency Integrated Circuits (RFIC) Symp., 2005. Digest of Papers. 2005 IEEE, 12–14 June 2005, 247–250.Google Scholar
[8]Bacqué, L. et al. : high efficiency and linear power amplification for OFDM signal by combining dynamic bias and digital baseband predistortion, in EuMC 2008, Amsterdam, 2008.CrossRefGoogle Scholar
[9]Guo, Y.; Cavallaro, J.R.: A novel adaptive pre-distorter using LS estimation of SSPA non-linearity in mobile OFDM systems. IEEE Int. Symp. Circuits Syst., 3 (2002), III-453–III-456.Google Scholar
[10]Besbes, H.; Le-Ngoc, T.: A fast adaptive predistorter for nonlinearly amplified M-QAM signals. IEEE Global Telecommun. Conf., 1 (2000), 108–112.CrossRefGoogle Scholar
[11]Park, J.-Y.; Burger, J.; Titizian, J.: UHF-band long-pulse radar power amplifiers using push-pull and balanced configurations. IEEE MTT-S Int. Microwave Symp. Dig., pp. 15–18, 3–8 June 2007.Google Scholar
[12]Keyzer, J.; Hinrichs, J.; Metzger, A.; Iwamoto, M.; Galton, I.; Asbeck, P.: Digital generation of rf signals for wireless communications with band-pass delta-sigma modulation. IEEE MTT-S Int. Microwave Symp. Dig., 3 (2001), 2127–2130.Google Scholar
[13]Wang, Y.: A class-S RF amplifier architecture with envelope delta-sigma modulation, in Radio and Wireless Conf., RAWCON, 11–14 August 2002, 177–179.Google Scholar
[14]Saari, V.; Juurkko, P.; Ryyanen, J.; Halonen, K.: 13.5 MHz class-s modulator for EER transmitter, in Norchip Conf. Proc., 8–9 November 2004, 253–256.Google Scholar
[15]Nanfack Nkondem, G. et al. , Characterization of Galileo Signal Correlation Losses Caused by Non Linear Power Amplification with Memory. IMS2008 Atlanta. session THP2H.CrossRefGoogle Scholar
[16]Savitzky, A.; Golay, M.: Smoothing and differentiation of data by simplified least squares procedures. Anal. Chem., 36 (1964), 1627–1639.Google Scholar