GaN HEMT Based Doherty Amplifier for 3.5-GHz WiMAX Applications

Moon, Jin Young; Kim, Jangheon; Kim, Ildu; Woo, Young Yun; Hong, Sungchul; Kim, Han Seok; Lee, Jong; Kim, Bumman

doi:10.1109/ecwt.2007.4404030

Cited by 8 publications

(6 citation statements)

References 10 publications

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“…Both amplifiers comply this specification, however the DPA has a better RCE value (-34 dB) than the class AB amplifier (-26 dB). This improved linearity performance of the DPA was also reported in a recent paper [3], in which the results were based on measurements. The reason of this linearity improvement yields on the cancellation of the third-order harmonic generation (coefficient gm3) between the carrier and peaking amplifier [1][2][3].…”

Section: Stability Analysissupporting

confidence: 79%

“…Among these, the Doherty power amplifier (DPA) has received lots of attention lately due to its simple architecture, efficiency range and inherently improved linearity [1][2][3]. In its basic configuration this amplifier comprises a carrier amplifier (CA) and a peak amplifier (PA).…”

Section: Introductionmentioning

confidence: 99%

“…2. In order to correct this response an offset transmission line [1][2][3] can be added at the output. The length of this transmission line can be tuned until a proper load line is observed as shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Doherty amplifier design for 3.5 GHz WiMAX considering load line and loop stability

Medina¹,

Schreurs²,

Angelov³

et al. 2008

2008 European Microwave Integrated Circuit Conference

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Legacy Doherty amplifier is characterized by using a larger transistor for the peak amplifier such that this reaches saturation with a smaller excitation signal. However due to device availability and modelling considerations, this is not often feasible. In this paper, the design and measurement of a Doherty amplifier utilizing only single sized device is realized. Unlike previous research works, intrinsic load line is utilized to tune the offset lines, as well as to verify the actual dynamic load principle. Stability aspects are covered for this type of amplifier, which are not normally included in earlier works. Finally an assessment of its applicability and benefits for WiMAX at 3.5 GHz is realized using a class AB amplifier as a comparison basis.978-2-87487-007-1

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Section: Stability Analysissupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Doherty amplifier design for 3.5 GHz WiMAX considering load line and loop stability

Medina¹,

Schreurs²,

Angelov³

et al. 2008

2008 European Microwave Integrated Circuit Conference

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show abstract

“…Also, an increase of operating power and frequency band of the WiMAX system has strongly required GaN high electron mobility transistor (HEMT) technology because of its high-breakdown voltage, high electron saturation velocity, high frequency, and high-power performance. For efficiency improvement, lots of research groups have developed GaN-based Doherty amplifiers using load-modulation technique or switch-mode class E/F amplifiers [1][2][3]. Furthermore, the Doherty amplifiers with class E or F amplifiers have been proposed for 2.1-GHz WCDMA application [4,5] to provide further improvement of efficiency.…”

Section: Introductionmentioning

confidence: 99%

Efficiency enhancement of the Doherty amplifier for 3.5 GHz WiMAX application using class‐F circuitry

Park

Kim

Yoo

et al. 2010

Micro & Optical Tech Letters

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A coupled-defected ground structure lowpass filters using inductive coupling for improved attenuation, Microwave Opt Technol Lett 50 (2008), 1541-1543.ABSTRACT: This article presents a high-power and high-efficiency saturated Doherty amplifier using a GaN high electron mobility transistor for 3.5 GHz Worldwide Interoperability for Microwave Access application. The saturated Doherty amplifier is a Doherty amplifier based on class-F amplifiers, resulting in higher efficiency than a conventional Doherty amplifier. The distributed-type harmonic control circuit is located between a power transistor and an output matching circuit. From the measured results for a continuous wave of 3.5 GHz, the saturated Doherty amplifier attains a high P 3dB of 45 dBm and a power gain of about 8.8 dB. Also, the proposed Doherty amplifier provides a high power-added-efficiency (PAE) of 37.7% and a drain efficiency of 42.7% at 6-dB back-off output power region from P 3dB , which are 8.7% and 5.7% higher than those of the conventional Doherty amplifier. Compared to the single class-AB amplifier, we obtain 17.7% and 19.7% improvement of PAE and drain efficiency, respectively.

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“…However, a transistor operated at this bias condition provides very high efficiency at the expense of poor linearity. Current wireless communication systems are required to have high linearity because of high data transfer rates; thus, the general approach is to employ a class-AB for the main amplifier and a class-C bias condition for the peaking amplifier [4,7].…”

Section: -1 Two-way Doherty Amplifiermentioning

confidence: 99%

GaN HEMT Based High Power and High Efficiency Doherty Amplifiers with Digital Pre-Distortion Correction for WiBro Applications

Park¹,

Kim²,

Yoo³

et al. 2011

Journal of electromagnetic engineering and science

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This paper presents high power and high efficiency Doherty amplifiers for 2.345 GHz wireless broadband (WiBro) applications that use a Nitronex 125-W (P3dB) GaN high electron mobility transistor (HEMT). Two-and three-way Doherty amplifiers and a saturated Doherty amplifier using Class-F circuitry are implemented. The measured result for a center frequency of 2.345 GHz shows that the two-way Doherty amplifier attains a high P3dB of 51.5 dBm, a gain of 12.5 dB, and a power-added efficiency (PAE) improvement of about 16 % compared to a single class AB amplifier at 6-dB back-off power region from P3dB. For a WiBro OFDMA signal, the Doherty amplifier provides an adjacent channel leakage ratio (ACLR) at 4.77 MHz offset that is -33 dBc at an output power of 42 dBm, which is a 9.5 dB back-off power region from P3dB. By employing a digital pre-distortion (DPD) technique, the ACLR of the Doherty amplifier is improved from -33 dBc to -48 dBc. The measured result for the same frequency shows that the three-way Doherty amplifier, which has a P3dB of 53.16 dBm and a gain of 10.3 dB, and the saturated Doherty amplifier, which has a P3dB of 51.1 dBm and a gain of 10.3 dB, provide a PAE improvement of 11 % at the 9-dB back-off power region and 7.5 % at the 6-dB back-off region, respectively, compared to the two-way Doherty amplifier.

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GaN HEMT Based Doherty Amplifier for 3.5-GHz WiMAX Applications

Cited by 8 publications

References 10 publications

Doherty amplifier design for 3.5 GHz WiMAX considering load line and loop stability

Doherty amplifier design for 3.5 GHz WiMAX considering load line and loop stability

Efficiency enhancement of the Doherty amplifier for 3.5 GHz WiMAX application using class‐F circuitry

GaN HEMT Based High Power and High Efficiency Doherty Amplifiers with Digital Pre-Distortion Correction for WiBro Applications

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