Frequency Response Analysis and Bandwidth Extension of the Doherty Amplifier

Bathich, Khaled; Markos, A. Z.; Boeck, Georg

doi:10.1109/tmtt.2010.2098040

Cited by 180 publications

(100 citation statements)

References 15 publications

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“…However, in practical DPAs, the limits imposed by these networks are hardly reached, since bandwidth is actually defined by the devices' output capacitances. In fact, as frequency moves away from the centre (design) value, the impedance seen from the Main drain at back-off deviates from its optimum value due to parasitic effects, and load modulation in the Doherty region results in being sensibly different from the theoretical one [74,75].…”

Section: Bandwidthmentioning

confidence: 98%

High Efficiency Power Amplifiers for Modern Mobile Communications: The Load-Modulation Approach

et al. 2017

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Abstract:Modern mobile communication signals require power amplifiers able to maintain very high efficiency in a wide range of output power levels, which is a major issue for classical power amplifier architectures. Following the load-modulation approach, efficiency enhancement is achieved by dynamically changing the amplifier load impedance as a function of the input power. In this paper, a review of the widely-adopted Doherty power amplifier and of the other load-modulation efficiency enhancement techniques is presented. The main theoretical aspects behind each method are introduced, and the most relevant practical implementations available in recent literature are reported and discussed.

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Section: Bandwidthmentioning

confidence: 98%

High Efficiency Power Amplifiers for Modern Mobile Communications: The Load-Modulation Approach

et al. 2017

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“…To improve efficiency at large OBO power level, Doherty power amplifiers (DPA) has been widely used due to its high efficiency at the reduced power condition [2,3,4,5,6,7,8]. To meet the increasing demand on information capacity, the signal modulation formats are becoming more and more complicated.…”

Section: Introductionmentioning

confidence: 99%

Bandwidth enhancement of three-device Doherty power amplifier based on symmetric devices

Cheng

Zhang

et al. 2018

IEICE Electron. Express

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This paper proposes a method for extending the bandwidth of a three-device Doherty power amplifier (DPA) based on symmetric devices. λ/4 transmission lines are inserted between each peaking amplifier output and carrier amplifier output to compensate load impedance of carrier amplifier. In order to achieve perfect load modulation, carrier amplifier output circuit total electrical length is designed to 90 degrees, and the peak amplifier output total electrical length is designed to 180 degrees. The proposed method is demonstrated by designing a three-device broadband DPA using three 10-W packaged GaN HEMT devices. Measurement results show that over 40% drain efficiency is achieved at 9-dB back-off power, over the frequency band of 1.45-2.35 GHz, accounting for 46% fractional bandwidth.

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“…Among others, the frequency-sensitive output combining network, input and output offset lines, as well as the frequency-dependent input impedance of the peaking device are dominant factors which limit the bandwidth capability of this amplifier architecture. Nevertheless, solutions have been recently proposed to extend the bandwidth of the Doherty amplifier [5][6][7][8][9][10][11][12][13][14]. Low-Q output combining network was implemented in [5] to extend the bandwidth up to 42%.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, solutions have been recently proposed to extend the bandwidth of the Doherty amplifier [5][6][7][8][9][10][11][12][13][14]. Low-Q output combining network was implemented in [5] to extend the bandwidth up to 42%. In [6,7], a technique was used to absorb the impedance degradation effect of the output combining network, resulting in high and more flat back-off performances over the targeted design bandwidths.…”

Section: Introductionmentioning

confidence: 99%

“…In Section III, an analysis of the bandwidth capability of the output combining network of asymmetrical Doherty amplifier will be derived and discussed. The derived expressions represent a generalized analysis of the output combining network that applies not only for 6 dB back-off operation as in [5] but also for any arbitrary back-off level configuration. Moreover, a compensation technique will be applied to absorb the effect of the output combining network over the targeted design band.…”

Section: Introductionmentioning

confidence: 99%

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Design and analysis of 80-W wideband asymmetrical Doherty amplifier

Bathich

Boeck

2014

Int. j. microw. wirel. technol.

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Design and analysis of 80-W wideband asymmetrical Doherty amplifier khaled bathich and georg boeckThis paper presents the analysis and design of a wideband asymmetrical Doherty amplifier. The frequency response of the output combining network of the Doherty amplifier with arbitrary back-off level configuration is analyzed. Other bandwidthlimiting factors were discussed and analyzed as well. A number of performance enhancement techniques were taken into consideration to obtain high and flat back-off efficiency over the amplifier design band of 1.7-2.25 GHz. The designed Doherty amplifier had, at 8.0-9.9 dB output back-off, a minimum efficiency of h ¼ 50% [power-added efficiency of 45%], measured near 40 dBm of output power, and over 28% bandwidth. Using digital predistortion (DPD) linearization, an adjacentchannel leakage ratio (ACLR) of 243 dBc was obtained for a single-carrier W-CDMA signal, at 40.9 dBm and 46% of average output power and drain efficiency, respectively. The designed amplifier represents the first wideband Doherty amplifier reported over extended power back-off range.

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Frequency Response Analysis and Bandwidth Extension of the Doherty Amplifier

Cited by 180 publications

References 15 publications

High Efficiency Power Amplifiers for Modern Mobile Communications: The Load-Modulation Approach

High Efficiency Power Amplifiers for Modern Mobile Communications: The Load-Modulation Approach

Bandwidth enhancement of three-device Doherty power amplifier based on symmetric devices

Design and analysis of 80-W wideband asymmetrical Doherty amplifier

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