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Session: WE2F10:10 AM Wednesday, May 26, 2010 Room: 208AB |
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Session: WE2F | Power Amplifier System Concepts. |
Chair: | John Wood, Freescale Semiconductor, Inc. |
Co-Chair: | Fadhel Ghannouchi, University of Calgary |
Abstract: | In this session, advanced concepts in the architectures and linearization of power amplifiers will be presented. The papers include developments in analog and digital pre-distorters, a technique for achieving high efficiency using second harmonic injection, and new developments in modulator design for envelope tracking power amplifiers. |
| | WE2F-1 | Behavioral Modeling and Digital Predistortion of Power Amplifiers with Memory using Two Hidden Layers Artificial Neural Networks | 10:10 AM-10:30 AM | F. Mkadem1, M. Ben Ayed1, S. Boumaiza1, J. Wood2, P. Aaen2, 1University of Waterloo, Waterloo, Canada, 2Freescale Semiconductor, Inc., Tempe, United States |
(1685) | This paper presents a novel Two Hidden Layers Neural Networks (2HLANN) model for behavioral modeling and linearization of RF PAs. Starting with a feedback loop principle model of a PA, an appropriate structure is deduced. This structure was then optimized to form a 2HLANN based model capable of predicting the nonlinear behavior and the memory effects of PAs. The validation of the proposed model in mimicking the behavior of a DUT is carried out in terms of its accuracy in predicting the output spectrum, dynamic AM/AM and AM/PM and the NMSE. In addition, the 2HLANN model was used to linearize two 250 Watt PEP Doherty PAs (DPAs) driven with 20 MHz bandwidth signals. The linearization of these DPAs using the 2HLANN enabled attaining an output power of 46.8 dBm and an average efficiency of up to 47.5% coupled with an ACPR higher than 50 dBc. When compared to some published behavioral and DPD schemes, the 2HLANN model demonstrated an excellent modeling accuracy and linearization capability | | |
WE2F-2 | High Accuracy Wide Band Analog Predistortion Linearizer for Telecom Satellite Transmit Section | 10:30 AM-10:50 AM | J. Villemazet, H. Yahi, D. Lopez, M. Perrel, J. Maynard, J. Cazaux, Thales Alenia Space France, Toulouse, France |
(1242) | This paper proposes a new predistortion linearizer module for TWTA allowing to reach high linearity performance on a wide frequency bandwidth for Telecom satellite transmit section. This linearizer module includes a new advanced shape tuning capability associated with an embedded limiting function. A C/I3 improvement of more than 16dB at –7dB IBO per carrier and a NPR increase of 5dB at -3dB OBO were for instance obtained thanks to this new linearizer architecture on the overall 10.7 – 12.75GHz Ku-band (2.05GHz bandwidth). NPR performance is now very close to the optimal theoretical response of the “ideal limiter”. | | |
WE2F-3 | Novel Wide Band High-Efficiency Active Harmonic Injection Power Amplifier Concept | 10:50 AM-11:10 AM | A. AlMuhaisen, P. Wright, J. Lees, P. Tasker, S. Cripps, J. Benedikt, Cardiff University, Cardiff, United Kingdom |
(1647) | This paper introduces a novel approach for the realization of wide band ( octave) high-efficiency ( 95%) high Power Amplifiers (PAs). The proposed concept utilizes active harmonic injection to achieve the appropriate waveform shaping of the voltage/current waveforms necessary to deliver simultaneously both high power and high efficiency operation. The new PA structure thus consists of two parallel PAs where the main PA generates fundamental power and an auxiliary PA injects a harmonic signal at the output of the main PA to perform waveform shaping. An active harmonic injection PA circuit designed around the 10W GaN transistor is demonstrated, along with the basic mathematical analysis and computer simulation of this new mode of operation. The measured performance of the PA demonstrator realized at 0.9 GHz provided a drain efficiency of 74.3% at P1dB, validating the concept and its potential. | | |
WE2F-4 | High Efficiency Envelope Tracking Supply Voltage Modulator for High Power Base Station Amplifier Applications | 11:10 AM-11:30 AM | T. M. Aitto-oja, Nokia Siemens Networks, Oulu, Finland |
(1072) | Wideband supply voltage modulator with efficiency of 85.1% with 7.5dB PAPR (Peak to average power ratio) (WCDMA, LTE, MC-GSM signals), 120W average output power and 91.7% with 0dB PAPR (GSM applications), 130W output power signals was built. Supply voltage modulator consists of parallel linear amplifier and switching stage. Linear amplifier is controlled by envelope signal, and novel method for controlling switching stage is presented, resulting in high efficiency and low sensitivity to component variations. New control achieved over 20%-unit efficiency improvement in back-off, and measured efficiency was above 80% over 14dB average power range with 7.5dB PAPR test signal. Modulator achieved 20MHz operation fulfilling linearity requirements. | | |
WE2F-5 | Wideband High Efficiency Digitally-Assisted Envelope Amplifier with Dual Switching Stages for Radio Base-Station Envelope Tracking Power Amplifiers | 11:30 AM-11:50 AM | C. Hsia1, D. F. KImball1, S. Lanfranco2, P. M. Asbeck1, 1University of California, San Diego, La Jolla, United States, 2Nokia Siemens Networks, Mountain View, United States |
(1332) | This paper presents a novel envelope amplifier architecture to improve the overall efficiency of wideband high linearity envelope tracking power amplifiers (PAs). We show here a technique to increase the efficiency of the envelope amplifier while maintaining the amplifier’s bandwidth. The overall system was demonstrated using a GaAs high voltage HBT PA. For a variety of signals ranging from 6.6dB to 9.6dB PAR and up to 10MHz bandwidth, the overall system PAE reached above 50%, with a normalized RMS error below 5% and ACLR1 of -50dBc with memory-less digital pre-distortion, at an average output power above 19W and gain of 10dB. The efficiencies obtained are the best ever reported, to our knowledge, for envelope tracking base station amplifiers for these signals. | | |
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