• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.2
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• pp.108-114
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• 2016

This paper presents a 2.6 GHz Doherty power amplifier IC to enhance the back-off efficiency. In order to apply to small-cell base stations, the Doherty power amplifier was fabricated using GaN-HEMT process for high power density. In addition, the implemented Doherty power amplifier was mounted on a QFN package. The implemented GaN-HEMT Doherty power amplifier was measured using LTE downlink signal with 10 MHz bandwidth and 6.5 dB PAPR for verification. A power gain of 15.8 dB, a drain efficiency of 43.0 %, and an ACLR of -30.0 dBc were obtained at an average output power level of 33.9 dBm.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.172-175
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• 2010

본 논문에서는 GaN HEMT를 이용하여 Jamming용 System에 사용될 수 있는 고효율 및 고출력 특성을 가지는 광대역 Amplifier를 제작하였다. Jamming System에서 핵심이 되는 Amplifier는 넓은 범위의 주파수에서 통상적으로 사용되는 출력 신호에 비해 보다 높은 출력의 신호를 구현하는 것이 중요하다. 본 논문에서는 GaN HEMT에 안정적인 전원 공급을 위한 음 전원 Bias 제어 회로와 Sequence 회로 및 온도에 따른 Gain 보상 회로를 구현하였으며, 500~2500MHz의 광대역에서 동작하면서 50W 이상의 출력을 낼 수 있도록 설계하였다. 출력 전력이 향상과 안정적인 동작을 위해 Main 출력 단은 60Watt 급의 GaN HEMT 소자와 광대역 Coupler를 이용하여 Balanced Structure로 설계하였다. 제작된 광대역 Amplifier는 30V 단일 전원에서 동작하도록 설계되었고, 크기는 140*90mm이다. 동작주파수 대역(500~2500MHz)에서 Small Signal Gain 63dB와 Gain Flatness ${\pm}$2dB, -10dB 이하의 Input Return Loss를 가진다. CW(Continuous Wave) Signal을 이용하여 측정하였으며, 50Watt 이상의 Saturation Power에서 최대 45%, 최소 28% 정도의 효율 특성을 보였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.5
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• pp.71-78
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• 2011

In this paper, we describe the design and implementation of a high efficiency and broad-band Class-J mode power amplifier using gallium nitride(GaN) high-electron mobility transistor(HEMT). The matching circuit of proposed class-J mode power amplifier for 2nd harmonic impedance designed to provide pure reactance alone. The measurement results show that output power of $40{\pm}1$ dBm, power-added efficiency of 50%, and drain efficiency of 60% for a continuous wave signal at 1.4 to 2.6 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.6
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• pp.540-545
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• 2015

This paper presents the design, fabrication and measurement results of a S-band internally-matched power amplifier using Gallium Nitride High Electron Mobility Transistor(GaN HEMT) die. In order to fabricate the S-band internally-matched power amplifier, a high dielectric substrate and alumina were used for input/output matching circuits. The measured output power is 55.4 dBm, the drain efficiency is 78 % and the power gain is 11 dB under pulse operation at the frequency of 3 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.11
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• pp.1064-1073
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• 2013

In this paper, a compact 370 W high efficiency GaN(Gallium Nitride) HEMT(High Electron Mobility Transistor) power amplifier(PA) using internal harmonic manipulation circuits is presented for cellular and L-band. We employed a new circuit topology for simultaneous high efficiency matching at both fundamental and 2nd harmonic frequency. In order to minimize package size, new 41.8 mm GaN HEMT and two MOS(Metal Oxide Semiconductor) capacitors are internally matched and combined package size $10.16{\times}10.16{\times}1.5Tmm^3$ through package material changes and wire bonded in a new package to improve thermal resistance. When drain biased at 48 V, the developed GaN HEMT power amplifier has achieved over 80 % Drain Efficiency(DE) from 770~870 MHz and 75 % DE at 1,805~1,880 MHz with 370 W peak output power(Psat.). This is the state-of-the-art efficiency and output power of GaN HEMT power amplifier at cellular and L-band to the best of our knowledge.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.1
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• pp.76-79
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• 2016

This paper describes the successful development and the performance of X-band 50 W pulsed power amplifier using a 50 W GaN-on-SiC high electron mobility transistor. The GaN HEMT with a gate length of $0.25{\mu}m$ and a total gate width of 12 mm were fabricated. The X-band pulsed power amplifier exhibited an output power of 50 W with a power gain of 6 dB in a frequency range of 9.2~9.5 GHz. It also shows a maximum output power density of 4.16 W/mm. This 50 W GaN HEMT and X-band 50 W pulsed power amplifier are suitable for the radar systems and related applications in X-band.

• Journal of IKEEE
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• v.23 no.2
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• pp.425-430
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• 2019

This work describes the design and characterization of a X-band power amplifier (PA) monolithic microwave integrated circuit (MMIC) using a $0.25{\mu}m$ gate length gallium nitride (GaN) high electron mobility transistor (HEMT) technology. The developed X-band power amplifier MMIC has small signal gain of over 22.7 dB and saturated output power of 43.02 dBm (20.04 W) over the entire band of 9 to 10 GHz. Maximum saturated output power is a 43.84 dBm (24.21 W) at 9.5 GHz. Its power added efficiency (PAE) is 41.0~51.24% and the chip dimensions are $3.7mm{\times}2.3mm$, generating the output power density of $2.84W/mm^2$. The developed GaN power amplifier MMIC is expected to be applied in a variety of X-band radar applications.

• Journal of electromagnetic engineering and science
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• v.17 no.4
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• pp.178-180
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• 2017

This study presents a 2-20 GHz monolithic distributed power amplifier (DPA) using a $0.25{\mu}m$ AlGaN/GaN on SiC high electron mobility transistor (HEMT) technology. The gate width of the HEMT was selected after considering the input capacitance of the unit cell that guarantees decade bandwidth. To achieve high output power using small transistors, a 12-stage DPA was designed with a non-uniform drain line impedance to provide optimal output power matching. The maximum operating frequency of the proposed DPA is above 20 GHz, which is higher than those of other DPAs manufactured with the same gate-length process. The measured output power and power-added efficiency of the DPA monolithic microwave integrated circuit (MMIC) are 35.3-38.6 dBm and 11.4%-31%, respectively, for 2-20 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.7
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• pp.620-626
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• 2015

In this paper, a 2~6 GHz wideband GaN power amplifier MMIC is designed and fabricated using a second-order all-pass filter for input impedance matching and an LC parallel resonant circuit for minimizing an output reactance component of the transistor. The second-order all-pass filter used for wideband lossy matching is modified in an asymmetric configuration to compensate the effect of channel resistance of the GaN transistor. The power amplifier MMIC chip that is fabricated using a $0.25{\mu}m$ GaN HEMT foundry process of Win Semiconductors, Corp. is $2.6mm{\times}1.3mm$ and shows a flat linear gain of about 13 dB and input return loss of larger than 10 dB. Under a saturated power mode, it also shows output power of 38.6~39.8 dBm and a power-added efficiency of 31.3~43.4 % in 2 to 6 GHz.

• Journal of IKEEE
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• v.26 no.4
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• pp.722-727
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• 2022

In this paper, we present the design and characterization of a power amplifier (PA) monolithic microwave integrated circuit (MMIC) in the X-band. The device is designed using a 0.25 ㎛ gate length AlGaN/GaN high electron mobility transistor (HEMT) on SiC process. The developed X-band AlGaN/GaN power amplifier MMIC achieves small signal gain of over 21.6 dB and output power more than 46.11 dBm (40.83 W) in the entire band of 9 GHz to 10 GHz. Its power added efficiency (PAE) is 43.09% ~ 44.47% and the chip dimensions are 3.6 mm × 4.3 mm. The generated output power density is 2.69 W/mm². It seems that the developed AlGaN/GaN power amplifier MMIC could be applicable to various X-band radar systems operating X-band.