Unequal-Cells-Based GaN HEMT Doherty Amplifier With an Extended Efficiency Range

Lee, Yong‐Sub; Lee, Mun‐Woo; Jeong, Yoon‐Ha

doi:10.1109/lmwc.2008.2001015

Cited by 44 publications

(24 citation statements)

References 10 publications

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“…Thus, as (7) concludes, efficiency at the TP depends on the Re{Z L,C }. As investigated in [19], the frequency dependent Re{Z L,C } can be given as in (8) for the conventional structure:…”

Section: Wideband Doherty Combinermentioning

confidence: 78%

“…However, the worst case efficiency related to the possible smallest Re{Z L,C } can be expressed in terms of the magnitude of Γ by using (7). This relation is plotted in Fig.…”

Section: Wideband Doherty Combinermentioning

confidence: 99%

“…The Doherty power amplifier (DPA) is a strong candidate for multimode multiband operation due to its low hardware complexity, wide aggregated instantaneous bandwidth and tunable efficiency characteristic for different power ranges [3][4][5]. In order to improve the efficiency, various kinds of DPA architecture, such as bias adapted DPA, asymmetrical DPA and multi-stage DPA, have been proposed [6][7][8][9][10]. There have been Doherty amplifiers reported with enhanced back-off efficiency and improved linearity by the utilization of the inter-modulation cancellation and digital predistortion techniques [11,12].…”

Section: Introductionmentioning

confidence: 99%

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Designing an Octave-Bandwidth Doherty Amplifier Using a Novel Power Combination Method

Sahan¹,

Demır²

2013

PIER B

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Abstract-In this paper, an octave bandwidth Doherty power amplifier (DPA) using a novel combiner is presented. The fundamental bandwidth limitation of the load modulation concept of a conventional Doherty structure is solved based on the proposed combination method. For verification, an octave bandwidth asymmetric Doherty architecture is implemented by using gallium-nitride (GaN) HEMT Cree CGH40010 and CGH40025 devices in the carrier and peaking amplifiers, respectively. The carrier and peaking amplifiers are designed to achieve optimal operation with 25 Ω load and source impedances. The reduced load and source impedances simplify the matching circuits for broadband operation. Key building blocks, including the proposed combiner, carrier and peaking amplifiers as well as the 50/25 Ω input power divider, are outlined. The measurement results represent higher than 37% and 52% drain efficiencies in 6 dB load modulation region across the frequency range from 0.85 to 1.85 GHz and 0.90 to 1.60 GHz, respectively. The implemented Doherty amplifier represents acceptable linearity across the whole operation frequency range. In two-tone signal characterization, the implemented DPA performs with a drain efficiency of 55% and an inter-modulation distortion (IMD) of −30 dBc at an average output power of 41.2 dBm at the center operation frequency of 1.35 GHz. In order to observe wideband signal characterization, a single carrier wideband code-division multiple access (W-CDMA) signal with a peak-to-average power ratio (PAPR) of 6.5 dB is applied and a drain efficiency of 51% with an adjacent-channel leakage ratio (ACLR) of −31 dBc is achieved at an average output power of 38.4 dBm.

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“…Thus, as (7) concludes, efficiency at the TP depends on the Re{Z L,C }. As investigated in [19], the frequency dependent Re{Z L,C } can be given as in (8) for the conventional structure:…”

Section: Wideband Doherty Combinermentioning

confidence: 78%

“…However, the worst case efficiency related to the possible smallest Re{Z L,C } can be expressed in terms of the magnitude of Γ by using (7). This relation is plotted in Fig.…”

Section: Wideband Doherty Combinermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Designing an Octave-Bandwidth Doherty Amplifier Using a Novel Power Combination Method

Sahan¹,

Demır²

2013

PIER B

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“…Eq. (4) can be satisfied with a 90°i nput phase offset line and proper input drive levels related with main and peaking amplifier's transconductance ratio [19,20]. Noting that Eq.…”

Section: Analysis Of the Basic Doherty Power Amplifiermentioning

confidence: 99%

Effect of input phase mismatch in Doherty power amplifiers

Aydın

Palamutcuogullari

Yarman

2016

IEICE Electron. Express

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In this paper, a new method is proposed to calculate transconductance ratio of the main and the peaking transistor of a Doherty power amplifier (DPA) which employs output matching circuits and offset lines. Cascade ABCD two-port parameters are used to analyze output section of the DPA. It is shown that output matching circuits has impact on the magnitude and the phase of the transconduction ratio. The effect of the input phase mismatch on the output power and efficiency is analyzed analytically. A 100 W dual drive Gallium Nitride (GaN) Doherty power amplifier is realized to experimentally verify the results. The drain efficiency measured as 68% at the correct phase, 65% for 30°input phase mismatch and 56% for 45°input phase mismatch.

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“…Recently, modulated signals in the modem communication systems have a high peak-to-average power ratio (P APR) of over 9 dB. Thus, various extended DPAs, such as N-way or multi-stage Ooherty structure, asymmetrical DPA using uneven device ratio, and so on [2]- [8], have reported to obtain high efficiency at a large BOP since the conventional DPA shows the peak efficiency at a 6-dB BOP. However, these extended DPAs have one of serious drawbacks as shown below.…”

Section: Introductionmentioning

confidence: 99%

Advanced design of a double Doherty power amplifier with a flat efficiency range

Lee

Kam

et al. 2010

2010 IEEE MTT-S International Microwave Symposium

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This paper reports a new double Doherty power amplifier (DDPA) with a flat efficiency range, which consists of two-stage amplifiers. When the two-way DPA is used as the main peaking amplifier, the driving peaking cell with c1ass-C bias turns the DPA off before the saturation of the main carrier amplifier. Three efficiency-peaking points are achieved with the additional Doherty operation by the main peaking amplifier after the saturation of the main carrier amplifier. For verifications, the driving and main amplifiers are designed and implemented with 2-W and 10-W GaN HEMTs, respectively, at 2.14 GHz. From the continuous wave (CW) results, three efficiency-peaking points are obtained at approximately 9-, 5-, and O-d8 back-off powers with over 42% drain efficiency. For one-carrier wide-band code division multiple access (WCDMA) signal, the DDPA shows good digital predistortion linearization performance.

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Unequal-Cells-Based GaN HEMT Doherty Amplifier With an Extended Efficiency Range

Cited by 44 publications

References 10 publications

Designing an Octave-Bandwidth Doherty Amplifier Using a Novel Power Combination Method

Designing an Octave-Bandwidth Doherty Amplifier Using a Novel Power Combination Method

Effect of input phase mismatch in Doherty power amplifiers

Advanced design of a double Doherty power amplifier with a flat efficiency range

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