Effect of input phase mismatch in Doherty power amplifiers

Aydın, Ömer; Palamutcuogullari, Osman; Yarman, Binboğa Sıddık

doi:10.1587/elex.13.20160870

Cited by 6 publications

(4 citation statements)

References 23 publications

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“…Input matching is critical since it governs the DPA efficiency, gain flatness and linearity through the correct AUX amplifier turn-on. A slow AUX turn-on often leads to a significant gain drop in both back-off and the Doherty region [6,18,21]. In conclusion, the DPA design is affected by several competing constrains calling for advanced optimization methods, most recently including neural networks [22][23][24] and digital control [25,26].…”

Section: Introductionmentioning

confidence: 99%

“…Simulations show that the AUX stage cannot be matched over the whole power range, since the input reflection coefficient varies significantly with power. Matching the AUX at peak power, we show that the phase of the AUX power source, akin to an input offset line [21], can be used to find the best compromise in terms of efficiency, gain and linearity. The MAIN stage is input-matched in back-off [6], where the gain is higher because of the higher load resistance with only 0.5 dB gain penalty at higher power.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Doherty Power Amplifier Matching Assisted by Physics-Based Device Modelling

2023

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The Doherty Power Amplifier represents one of the most promising solutions for the design of high-efficiency power stages. In the widely adopted ABC scheme, the Doherty Amplifier design critically depends on the accuracy of the device model in different operating conditions, ranging from class AB to class C. For the class C case, library models are often inaccurate, while experimental characterization is difficult since it must be carried out in large signal conditions and with varying gate bias. In this paper, we propose an alternative approach, based on physics-based Technological CAD (TCAD) simulations of the complete Doherty amplifier along with the analysis of its individual MAIN (class AB) and AUXILIARY (class C) stages. TCAD simulations seamlessly provide an accurate modelling of the device behavior in all operation classes, including the device turn-on and the nonlinear capacitances, and easily account for the cross-loading effects of the MAIN and AUXILIARY devices through the output network and the effect of the device feedback (gate-drain) capacitance on the input matching. Analyzing a GaAs Doherty stage at 12 GHz, we show that the input phase of the auxiliary stage can be exploited for the Doherty power amplifier optimization in terms of gain, linearity and efficiency, showing a 9 dB gain with less than 1 dB gain variation from back-off to peak power with a power-added efficiency exceeding 45% over a Doherty region extending to a more than 6 dB output power back-off.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analysis of Doherty Power Amplifier Matching Assisted by Physics-Based Device Modelling

2023

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“…However, this also results in a problem that the peak-toaverage power ratio (PAPR) of the signal increases significantly to about 8-12 dB, which requires the power amplifier to maintain high efficiency at a large output power back-off (OPBO) range [6,7,8,9]. The techniques that can improve the efficiency at OPBO are important issues in the research [10,11,12,13,14]. So, several Doherty power amplifiers (DPAs) have been investigated and developed [15,16,17,18,19].…”

Section: Introductionmentioning

confidence: 99%

Design of a 12dB back-off asymmetric Doherty power amplifier using reactive output impedance

Xia

Zhang

Cai

et al. 2020

IEICE Electron. Express

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This paper presents a method to extend the back-off range of an asymmetric Doherty power amplifier (DPA) to 12 dB using a reactive output impedance of the peaking amplifier. An analytical method is employed to determine the desired reactive output impedance for specific output power back-off (OPBO) range. Then, a peaking output matching network is designed to achieve the desired impedance to enlarge the efficiency of the carrier amplifier. When compared with conventional design, the OPBO range can be improved by about 2 dB using the proposed method. For verification, a 3.4-3.6 GHz asymmetric DPA with enhanced OPBO range was designed using 10 and 30 W GaN HEMT transistors. The measured efficiencies of 47%-49% at 12 dB back-off and 63%-66% at saturation are obtained over the whole frequency range. For a 40 MHz LTE signal at 3.5 GHz, the adjacent channel leakage ratio is −50 dBc after linearization with an average efficiency of higher than 50%.

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“…To amplify these signals efficiently, the power amplifiers (PAs) require efficiency enhancement at back-off powers [1]. Thus, the Doherty power amplifier (DPA) has been extensively used due to its simple implementation and significant efficiency enhancement [2,3,4,5,6,7,8,9]. To further improve the efficiency, the harmonic controlled DPAs based on class-F and class-J modes have been presented [10,11].…”

Section: Introductionmentioning

confidence: 99%

A harmonic controlled symmetric Doherty power amplifier with extended back-off power range

Xia

Zhu

Ding

et al. 2018

IEICE Electron. Express

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This paper proposes a harmonic controlled symmetric Doherty power amplifier (DPA) for large back-off applications. For efficiency enhancement, the harmonic impedances of the carrier and peaking amplifiers are controlled in the continuous class-F mode. To extend the back-off range, unlike the traditional DPA, the output impedance of the peaking amplifier locates far away from infinity at the edge of the Smith chart, which can further improve the efficiency of the carrier amplifier. For verification, a 3.3-3.8 GHz symmetric DPA was designed and measured. The designed DPA can deliver an efficiency of 45%-48% at 9 dB back-off power over the whole frequency band with a maximum output power larger than 44 dBm. When driven by a 40-MHz modulated signal, the DPA exhibits an adjacent channel leakage ratio of better than -50 dBc after linearization at an average output power of 36.5 dBm.

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Effect of input phase mismatch in Doherty power amplifiers

Cited by 6 publications

References 23 publications

Analysis of Doherty Power Amplifier Matching Assisted by Physics-Based Device Modelling

Analysis of Doherty Power Amplifier Matching Assisted by Physics-Based Device Modelling

Design of a 12dB back-off asymmetric Doherty power amplifier using reactive output impedance

A harmonic controlled symmetric Doherty power amplifier with extended back-off power range

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