A 2.6GHz band 537W peak power GaN HEMT asymmetric Doherty amplifier with 48% drain efficiency at 7dB

Deguchi, Hiroaki; Watanabe, Naoharu; Kawano, Akihiro; Yoshimura, Natsue; Ui, Norihiko; Ebihara, Koji

doi:10.1109/mwsym.2012.6258262

Cited by 17 publications

(6 citation statements)

References 6 publications

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“…Table I summarizes the measured amplifier performances and compares them with other state-of-the-art GaN FET amplifiers. These results are comparable to the best performance of the GaN on SiC FET high-power amplifiers [14]. As described above, our newly developed GaN FET on the LR Si substrate technology contributes to the coexistence of high performance and low cost in the high-power microwave GaN device.…”

Section: B 537-w Two-way Inverted Doherty Amplifiersupporting

confidence: 76%

High-Efficiency and High-Power Microwave Amplifier Using GaN-on-Si FET With Improved High-Temperature Operation Characteristics

Takenaka

Ishikura

Asano

et al. 2014

IEEE Trans. Microwave Theory Techn.

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We have successfully developed high-efficiency and high-power microwave amplifiers using a GaN field-effect transistor (FET) on a low-resistivity (LR) Si substrate for the first time. By introducing the LR Si substrate whose resistivity is less sensitive over temperature, the efficiency characteristics in high-temperature operation were significantly improved. In order to overcome the RF loss increase due to the utilization of the LR Si substrate, we have optimized the device structure of the FET by using an RC loss model accounting for drain-to-source capacitance and substrate resistance. High-efficiency characteristics were realized by optimizing the buffer structure and electrode structure. Furthermore, we have investigated efficiency improvement by second harmonic termination. The developed single-ended amplifier realized the saturation output power of 54 dBm, the linear gain (GL) of 19 dB, and the high efficiency of 33.5% at 8-dB back-off output power level under a WCDMA signal condition of 2.14 GHz at 50-V operation. The inverted Doherty amplifier using a pair of the 250-W GaN FETs delivered the of 57.3 dBm with the GL of 15.5 dB under a pulsed continuous wave signal condition of 2.14 GHz, and demonstrated the digital pre-distortion linearization characteristics with the high efficiency of 48% and the adjacent channel leakage power ratio of 55 dBc at 50 dBm. These results are comparable to the best performance among the ever reported GaN on SiC FET high-power amplifiers.Index Terms-GaN field-effect transistor (FET), high efficiency, high power, high temperature, inverted Doherty amplifier, microwave amplifiers, resistivity, second harmonic, Si substrate.

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Section: B 537-w Two-way Inverted Doherty Amplifiersupporting

confidence: 76%

High-Efficiency and High-Power Microwave Amplifier Using GaN-on-Si FET With Improved High-Temperature Operation Characteristics

Takenaka

Ishikura

Asano

et al. 2014

IEEE Trans. Microwave Theory Techn.

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“…While the Doherty architecture and its extensions (e.g., [5]- [7]) and envelope-tracking amplifier systems (e.g., [8], [9]) partially take advantage of saturated operation by utilizing saturation of the PA for a portion of the amplifier system or over a portion of the operating range, architectures that can leverage saturation (or switched-mode operation) over all or nearly all of the operating range have the potential for the highest efficiencies. Such architectures include polar amplifiers employing envelope elimination and restoration, or EER [10]- [12], amplifier systems utilizing direct load modulation of the power amplifier through electronic tuning [13]- [15], and outphasing amplifier systems [16]- [38].…”

Section: Introductionmentioning

confidence: 99%

Four-Way Microstrip-Based Power Combining for Microwave Outphasing Power Amplifiers

Barton

Perreault

2014

IEEE Trans. Circuits Syst. I

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Abstract-A lossless multi-way outphasing and power combining system for microwave power amplification is presented. The architecture addresses one of the primary drawbacks of Chireix outphasing; namely, the sub-optimal loading conditions for the branch power amplifiers. In the proposed system, four saturated power amplifiers interact through a lossless power combining network to produce nearly resistive load modulation over a 10:1 range of output powers. This work focuses on two microstrip-based power combiner implementations: a hybrid microstrip/discrete implementation using a combination of microstrip transmission line sections with discrete shunt elements, and an all-microstrip implementation incorporating open-circuited radial stubs. We demonstrate and compare these techniques in a 2.14 GHz power amplifier system. With the allmicrostrip implementation, the system demonstrates a peak CW drain efficiency of 70% and drain efficiency of over 60% over a 6.5-dB outphasing output power range with a peak power of over 100 W. We demonstrate W-CDMA modulation with 55.6% average modulated efficiency at 14.1 W average output power for a 9.15-dB peak to average power ratio (PAPR) signal. The performance of this all-microstrip system is compared to that of the proposed hybrid microstrip/discrete version and a previously reported implementation in discrete lumped-element form.Index Terms-base stations, outphasing, power amplifier (PA), wideband code division multiple access (W-CDMA), Chireix, LINC, load modulation.

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“…1, if one further assumes that the PAs are outphased according the phasor relationship in Fig. 1 with all input-port voltages V A -V D having the same magnitude V S (at the combiner operating frequency), then one can solve (6) for the effective admittance Y eff,A -Y eff,D each of the PAs sees looking into the combiner as a function of the outphasing angles θ and φ with all other PAs active. As can be seen from (7), Y eff,A and Y eff,D , as well as Y eff,B and Y eff,C are complex conjugate pairs.…”

Section: A Input-port Admittance Characteristicsmentioning

confidence: 99%

“…In order to maintain high efficiency over a wide dynamic range, then, a promising approach is to exploit the saturated efficiency characteristic by continuing to operate in a saturated mode even as output power is modulated. Output power of a saturated PA can be controlled for example by modulating either the drain terminal, as in polar and envelope tracking techniques [1]- [3], modulation of the effective load impedance as in Doherty [4]- [6], outphasing [7]- [38], or direct load modulation [39]- [41] architectures, or through a combination of these approaches [42], [43]. In principle, the average modulated efficiency of these techniques is directly related to the extent to which saturated operation can be maintained.…”

Section: Introductionmentioning

confidence: 99%

Multi-Way Lossless Outphasing System Based on an All-Transmission-Line Combiner

Barton

Jurkov

Pednekar

et al. 2016

IEEE Trans. Microwave Theory Techn.

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Abstract-A lossless power combining network comprising cascaded transmission line segments in a tree structure is introduced for a multi-way outphasing architecture. This architecture addresses the suboptimal loading conditions in Chireix outphasing transmitters while offering a compact and microwavefriendly implementation compared to previous techniques. In the proposed system, four saturated power amplifiers interact through an all-transmission-line power combining network to produce nearly ideal resistive load modulation of the branch power amplifiers over a 10:1 range of output powers. This work focuses on the operation of the combining network, deriving analytical expressions for input-port admittance characteristics and an outphasing control strategy to modulate output power while minimizing reactive loading of the saturated branch amplifiers. A methodology for combiner design is given, along with a combiner design example for compact layout. An experimental four-way outphasing amplifier system operating at 2.14 GHz demonstrates the technique with greater than 60% drain efficiency for an output power range of 6.2 dB. The system demonstrates a W-CDMA modulated signal with a 9.15-dB peak to average power ratio (PAPR) with 54.5% average modulated efficiency at 41.1 dBm average output power.Index Terms-base stations, outphasing, power amplifier (PA), wideband code division multiple access (W-CDMA), Chireix, LINC, load modulation.

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A 2.6GHz band 537W peak power GaN HEMT asymmetric Doherty amplifier with 48% drain efficiency at 7dB

Cited by 17 publications

References 6 publications

High-Efficiency and High-Power Microwave Amplifier Using GaN-on-Si FET With Improved High-Temperature Operation Characteristics

High-Efficiency and High-Power Microwave Amplifier Using GaN-on-Si FET With Improved High-Temperature Operation Characteristics

Four-Way Microstrip-Based Power Combining for Microwave Outphasing Power Amplifiers

Multi-Way Lossless Outphasing System Based on an All-Transmission-Line Combiner

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