Skip to main content Accessibility help
×
Home

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

  • Ludovic Bacque (a1), Gregoire Nanfack-Nkondem (a2), Philippe Bouysse (a1), Guillaume Neveux (a2), Jean Michel Nebus (a2), William Rebernak (a3), Luc Lapierre (a4), Denis Barataud (a2) and Raymond Quéré (a1)...

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).

Copyright

Corresponding author

Corresponding author: P. Bouysse Email: philippe.bouysse@xlim.fr

References

Hide All
[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), 633642.
[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), 4951.
[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, 2125.
[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), 38483856.
[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), 11321141.
[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), 10771081.
[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, 247250.
[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.
[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-453III-456.
[10]Besbes, H.; Le-Ngoc, T.: A fast adaptive predistorter for nonlinearly amplified M-QAM signals. IEEE Global Telecommun. Conf., 1 (2000), 108112.
[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.
[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), 21272130.
[13]Wang, Y.: A class-S RF amplifier architecture with envelope delta-sigma modulation, in Radio and Wireless Conf., RAWCON, 11–14 August 2002, 177179.
[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, 253256.
[15]Nanfack Nkondem, G. et al. , Characterization of Galileo Signal Correlation Losses Caused by Non Linear Power Amplification with Memory. IMS2008 Atlanta. session THP2H.
[16]Savitzky, A.; Golay, M.: Smoothing and differentiation of data by simplified least squares procedures. Anal. Chem., 36 (1964), 16271639.

Keywords

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

  • Ludovic Bacque (a1), Gregoire Nanfack-Nkondem (a2), Philippe Bouysse (a1), Guillaume Neveux (a2), Jean Michel Nebus (a2), William Rebernak (a3), Luc Lapierre (a4), Denis Barataud (a2) and Raymond Quéré (a1)...

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed