Hostname: page-component-586b7cd67f-tf8b9 Total loading time: 0 Render date: 2024-11-24T21:01:18.886Z Has data issue: false hasContentIssue false
  • English
  • Français

High linearity lead-lag style envelope modulator for RF power amplifiers

Published online by Cambridge University Press:  01 April 2015

Gavin T. Watkins  and
Konstantinos Mimis
Gavin T. Watkins*
Affiliation:
Toshiba Research Europe Limited, 32 Queen Square, Bristol, BS1 4ND, UK. Phone: +44 117 906 0740
Konstantinos Mimis
Affiliation:
Toshiba Research Europe Limited, 32 Queen Square, Bristol, BS1 4ND, UK. Phone: +44 117 906 0740
*
Corresponding author: G. T. Watkins Email: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

A new split frequency envelope modulator for envelope tracking radio-frequency power amplifiers is proposed based on a lead-lag network. By mathematically deriving the transfer functions of the lead-lag modulator and the conventional split frequency type, the lead-lag is shown to have a significantly flatter phase response. The frequency response of the two modulators is verified by simulation, where the phase transient of the lead-lag is significantly less than the 360° of the conventional type. They are further simulated with a 3 MHz bandwidth 3GPP long-term evolution (LTE) signal and the lead-lag shown to reduce the modulator's normalized root-mean-square error (NRMSE) from −27.3 to −39.2 dB. A practical demonstrator was developed around an existing high-efficiency modulator architecture. To maintain system efficiency synthetic impedance was incorporated in the low-frequency switched mode power supply (SMPS) path. This was achieved with voltage and current feedback around the SMPS. The dynamic wideband signal response was investigated by applying a 3 MHz LTE envelope signal to the modulator and comparing the input and output signals. The measured NRMSE was improved from −27.5 to −30.0 dB by adopting the lead-lag structure and the dynamic frequency response verifies correct operation.

Keywords

Active array antennas and componentsPower amplifiers and linearizers
Type
Research Paper
Information
International Journal of Microwave and Wireless Technologies , Volume 8 , Issue 3: Journee Nationale des Micro-ondes (JNM) 2015 , May 2016 , pp. 463 - 470
Copyright
Copyright © Cambridge University Press and the European Microwave Association 2015 

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]Kahn, L.R.: Single-sideband transmission by envelope elimination and restoration. Proc. IRE, 40 (7) (1952), 803–806.CrossRefGoogle Scholar
[2]3GPP TS 36.211 E-UTRA specifications.Google Scholar
[3]Habler, F.; Ellinger, F.; Jorges, U.; Wolf, R.; Lindner, B.: A high-speed buck converter for efficiency enhancement of W-CDMA power amplifiers. Int. J. Microw. Wireless Technol., 4 (5) (2012), 505–514.Google Scholar
[4]Augeau, P.; Bouysse, P.; Martin, A.; Nebus, J.M.; Quéréa, R.; Lapierrea, L.; Jardela, O.; Piotrowicz, S.: A new GaN-based high-speed and high-power switching circuit for envelope-tracking modulators. Int. J. Microw. Wireless Technol., 6 (1) (2014), 13–21.CrossRefGoogle Scholar
[5]Raab, R.H.: Split-band modulator for Kahn-technique, in 2004 IEEE MTTS Int. Microwave Symp. Digest, Fort Worth, USA, 2 (2004), 887–890.Google Scholar
[6]Yousefzadeh, V.; Alarcon, E.; Makismovic, D.: Efficiency optimization in linear-assisted switching power converters for envelope tracking in RF power amplifiers, in IEEE Int. Symp. on Circuits and Systems, ISCAS 2005, Kobe, Japan, 2005, 1302–1305.Google Scholar
[7]Egan, W.F.: Frequency Synthesis by Phase Loop. John Wiley & Sons, USA, 1981, ISBN 0-471-08202-3, 177–180.Google Scholar
[8]Watkins, G.T.: Wideband class B amplifiers for split frequency envelope modulated RF power amplifiers, in 2013 Spring Automated RF & Microwave Measurement Society (ARMMS) Conf., Steventon, UK, 2013, 1–9.Google Scholar
[9]Hong, Y.; Mukai, K.; Gheidi, H.; Shinjo, S.; Asbeck, P.M.: High efficiency GaN switching converter IC with bootstrap driver for envelope tracking applications, in IEEE Radio Frequency Integrated Circuits Symp., Seattle, USA, 2013, 353–356.CrossRefGoogle Scholar
[10]Kato, T.; Funahashi, Y.; Yamaoka, A.; Yamaguchi, K.; Jiafeng, Z.; Morris, K.; Watkins, G.T.: Performance of a frequency compensated EER-PA with memoryless DPD, in Asian Pacific Microwave Conf. Proc. (APMC), 2010 Asia-Pacific, Yokohama, Japan, 2010, 9–12.Google Scholar
[11]Hassan, M.; Larson, L.E.; Leung, V.W.; Asbeck, P.M.: Effect of envelope amplifier nonlinearities on the output spectrum of Envelope Tracking Power Amplifiers, in IEEE 12th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems (SiRF), Santa Clara, USA, 2012, 187–190.CrossRefGoogle Scholar
[12]Jordan, V.: Save 3 dB of output power using feedback to set the output impedance. EDN, 56 (10) (2011), 44–46.Google Scholar
[13]Cantrell, W.H.: Circuit to aid tuning of class-E amplifier, in 2000 IEEE MTTS Int. Microwave Symp. Digest, Boston, USA, vol. 2, 2000, 787–790.Google Scholar
[14]ZVN2110A switching MOSFET transistor, datasheet available from http://www.diodes.comGoogle Scholar
[15]PD85004 RF LDMOS transistor, datasheet available from http://www.st.comGoogle Scholar
[16]Hsia, C.; Zhu, A.; Yan, J.J.; Draxler, P.; Kimball, D.; Lanfranco, S.; Asbeck, P.M.: Digitally assisted dual-switch high-efficiency envelope amplifier for envelope tracking base-station power amplifiers. IEEE Trans. Microw. Theory Tech., 59 (11) (2011), 2943–2952.CrossRefGoogle Scholar
[17]Kim, J.H.; Son, H.S.; Kim, W.Y.; Park, C.S.: Envelope amplifier with multiple-linear regulator for envelope tracking power amplifier. IEEE Trans. Microw. Theory Tech., 61 (11) (2013), 3951–3960.CrossRefGoogle Scholar
[18]Aitto-Oja, T.: High efficiency envelope tracking supply voltage modulator for high power base station amplifier applications, in 2010 IEEE MTTS Int. Microwave Symp. Digest, Anaheim, CA, 2010, 668–671.CrossRefGoogle Scholar
[19]Wang, Z.: Nested and multi-nested supply modulator for an envelope tracking power amplifier. RF Technol. Int., 1 (10) (2012), 22–30.Google Scholar
[20]Yan, J.J.; Theilmann, P.; Kimball, D.F.: A high efficiency 780 MHz GaN envelope tracking power amplifier, in IEEE Compound Semiconductor Integrated Circuit Symp., La Jolla, USA, 2012, 1–4.CrossRefGoogle Scholar
[21]Warr, P.A.; Morris, K.A.; Watkins, G.T.; Horseman, T.R.; Takasuka, K.; Uedo, Y.; Kobayashi, Y.; Miya, S.: A 60% PAE WCDMA handset transmitter amplifier. IEEE Trans. Microw. Theory Tech., 57 (10) (2009), 2368–2377.CrossRefGoogle Scholar