High Electron Mobility Transistors Power Amplifier Research Articles

Design of a wideband highly efficient GaN HEMT power amplifier for multiband applications

AbstractA distributed basic matching network (MN) designed method that can achieve multioctave bandwidth and highly efficient power amplifier (PA) for multiband applications is presented in this letter. The distributed network unit with a left-rotating T-type structure is employed to construct the wideband MN, whose topology and circuit parameters are acquired through optimization. Finally, the impedance realized by the designed MN falls into the target impedance region obtained by using multi-harmonic bilateral pull technique in the desired frequency band. For the proof of the method, a broadband highly efficient PA has been designed, fabricated, and measured using commercialized GaN high electron mobility transistors (HEMT). The measured results show that the implemented PA achieves a bandwidth of 137.8% from 0.7 to 3.8 GHz. The drain efficiency is between 59% and 70% with an output power of greater than 39 dBm and a gain ranging from 9 to 12.1 dB.

A 50 W dual‐band high‐efficiency gallium nitride high electron mobility transistor power amplifier with three‐stage L‐type DC bias circuit at 1.8 and 2.6 GHz

AbstractA 50 W dual‐band high‐efficiency gallium nitride (GaN) high electron mobility transistor (HEMT) power amplifier with a three‐stage L‐type DC bias circuit capable of individually adjusting second‐harmonic impedances is proposed for 1.8 and 2.6 GHz frequencies. The output network of this power amplifier is composed of an output matching network comprising five‐stage transmission lines and a three‐stage L‐type DC bias circuit with three L‐type circuits and one transmission line. The one‐stage L‐type circuit comprises a series transmission line and a quarter‐wavelength open‐ended shunt stub. For the high‐efficiency performance of the power amplifier, the output matching network is matched to the optimum impedances of the fundamental frequencies, and the DC bias circuit optimizes the impedances individually at the second‐harmonic frequencies without affecting the matched fundamental frequency impedances in the output matching network. Measured results show that the proposed dual‐band GaN HEMT power amplifier achieved gains of 15.6 and 13.8 dB as well as maximum power‐added efficiencies of 70.5% and 66.3% with 47 dBm output power at 1.8 and 2.6 GHz, respectively.

Guidelines for Reduced-Order Thermal Modeling of Multifinger GaN HEMTs

Abstract The increasing demand for tightly integrated gallium nitride high electron mobility transistors (HEMT) into electronics systems requires accurate thermal evaluation. While these devices exhibit favorable electrical characteristics, the performance and reliability suffer from elevated operating temperatures. Localized device self-heating, with peak channel and die level heat fluxes of the order of 1 MW cm−2 and 1 kW cm−2, respectively, presents a need for thermal management that is reliant on accurate channel temperature predictions. In this publication, a high-fidelity multiphysics modeling approach employing one-way electrothermal coupling is validated against experimental results from Raman thermometry of a 60-finger gallium nitride (GaN) HEMT power amplifier under a set of direct current (DC)-bias conditions. A survey of commonly assumed reduced-order approximations, in the form of numerical and analytical models, are systematically evaluated with comparisons to the peak channel temperature rise of the coupled multiphysics model. Recommendations of modeling assumptions are made relating to heat generation, material properties, and composite layer discretization for numerical and analytical models. The importance of electrothermal coupling is emphasized given the structural and bias condition effect on the heat generation profile. Discretization of the composite layers, with temperature-dependent thermal properties that are physically representative, are also recommended.

A $V$ -Band Stacked HEMT Power Amplifier With 25-dBm Saturated Output Power in 0.1- $\mu \text{m}$ InGaAs Technology

A stacked high-electron mobility transistor (HEMT) power amplifier (PA) has been designed and implemented in a commercial 0.1- $\mu \text{m}$ InGaAs pHEMT process to increase gain and output power at millimeter-wave frequencies. The stability problem of the stacked HEMT has been analyzed. A new layout of the stacked HEMT for improving the high frequency stability is proposed and used in the PA design. Measurements on the three-stage PA with parallel devices verify the saturated output power of 25 dBm and the maximum power added efficiency of 15% at 61 GHz, which is the highest reported output power of stacked HEMT PAs. The chip size measures 3.2 mm2 which makes this the most power dense $V$ -band amplifier reported from GaAs with 100 mW/mm2.

A novel nonlinear large‐signal statistical model of GaN HEMT used in S‐band power amplifier design and yield estimation

SummaryA novel GaN high‐electron mobility transistor (HEMT) nonlinear large‐signal statistical model based on empirical equivalent circuit is proposed in this paper. Thirty‐four GaN HEMTs from 10 batches are measured, and all the parameters of the large‐signal model are extracted by in‐house parameter extraction program. We choose six most sensitive parameters of the drain‐source current model and the gate charge model. The statistical method is modeled by using a symbolic processing method to change the range of the six parameters. The statistical model is implemented in Agilent ADS software for validation. A S‐band GaN HEMT power amplifier is designed by using the established statistical model for demonstration purpose. The results show that good accuracy has been achieved by comparing measured and simulated output power (Pout) and power added efficiency (PAE). So it has been proven that this method is suitable for GaN HEMT power amplifier design and yield estimation. Copyright © 2016 John Wiley & Sons, Ltd.

Design of Ku‐band GaN HEMT power amplifier based on multi‐bias statistical model

AbstractA design method for microwave GaN high‐electron mobility transistor (HEMT) power amplifier based on equivalent circuit parameters multi‐bias statistical models is presented. The statistical modeling method includes principal component analysis, factor analysis, and multiple regressions modeling techniques. The statistical model is validated by comparing original and Monte Carlo‐simulated means, standard deviations, correlation matrix, and S‐parameters. A Ku‐band GaN HEMT power amplifier is designed with high drain efficiency by using the established statistical model for demonstration purpose. The simulated results are statistically indistinguishable from the measured results. This method is suitable for GaN HEMT power amplifier design and yield analysis. Copyright © 2015 John Wiley & Sons, Ltd.

내부 고조파 조정 회로로 구성되는 고효율 370 W GaN HEMT 소형 전력 증폭기

본 논문에서는 내부 고조파 조정 회로로 구성되는 셀룰러와 L-대역용 소형의 고효율 370 W GaN(Gallium Nitride) HEMT(High Electron Mobility Transistor) 소형 전력 증폭기(PA)를 구현하였다. 원천 및 2차 고조파 주파수에서 동시에 높은 효율을 내기 위해 새로운 회로 정합 형태를 적용했다. 소형화를 위하여 새로운 41.8 mm GaN HEMT와 2개의 MOS(Metal Oxide Semiconductor) 캐패시터를 구성 물질의 변화를 이용하여 열 저항을 개선한 <TEX>$10.16{\times}10.16{\times}1.5Tmm^3$</TEX> 크기의 새로운 패키지에 와이어 본딩으로 결합하였다. 드레인 바이어스 48 V 인가 시, 개발된 GaN HEMT 전력 증폭기는 370 W 포화 출력 전력(Psat.)과 770~870 MHz에서 80 % 이상, 1,805~1,880 MHz에서 75 % 이상의 드레인 효율(DE)을 나타내었다. 이는 지금까지 보고된 셀룰러와 L대역에서 GaN HEMT 전력 증폭기 중 최고의 효율과 출력 전력 특성이다. 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 <TEX>$10.16{\times}10.16{\times}1.5Tmm^3$</TEX> 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.

Compact hybrid broadband GaN HEMT power amplifier based on feedback technique

A broadband hybrid power amplifier using a gallium nitride (GaN) high electron mobility transistor (HEMT) is presented. A discrete GaN HEMT bare die with 1.25 mm of gate width is used, and a compact size of 8.3 × 12.7 mm is achieved by using a feedback technique based on lumped elements. The power amplifier operates from 100 to 1000 MHz, and shows more than 12.8 dB gain and higher than 30.7 dBm output power in the overall bandwidth. Power added efficiency of 61.3% was acquired at the mid-band frequency and more than 54.5% throughout the bandwidth.

A 24 W Ku band GaN based power amplifier with 9.1 dB linear gain

A Ku-band power amplifier is successfully developed with a single chip 4.8mm AlGaN/GaN high electron mobility transistors (HEMTs). The AlGaN/GaN HEMTs device, achieved by E-beam lithography г-gate process, exhibited a gate-drain reverse breakdown voltage of larger than 100V, a cutoff frequency of fT=30GHz and a maximum available gain of 13dB at 14GHz. The pulsed condition (100μs pulse period and 10% duty cycle) was used to test the power characteristic of the power amplifier. At the frequency of 13.9GHz, the developed GaN HEMTs power amplifier delivers a 43.8dBm (24W) saturated output power with 9.1dB linear gain and 34.6% maximum power-added efficiency (PAE) with a drain voltage of 30V. To our best knowledge, it is the state-of-the-art result ever reported for internal-matched 4.8mm single chip GaN HEMTs power amplifier at Ku-band.

An over 100 W AlGaN/GaN enhancement‐mode HEMT power amplifier with piezoelectric‐induced cap structure

AbstractA novel piezoelectric‐induced cap structure in an AlGaN/GaN high electron mobility transistor (HEMT) was developed for enhancement‐mode (E‐mode) operation with high maximum drain current density (Idmax), high breakdown voltage (BVgd) and small current collapse. Our developed cap structure consists of a thin GaN/AlN/ GaN triple‐layer, which reduces the sheet resistance (Rsh) due to conduction band bending. The threshold voltage (Vth) is +0.25 V with a high Idmax of 520 mA/mm, a high BVgd of 336 V and small current collapse by using the developed cap structure and a gate recess technique. The single‐chip AlGaN/GaN E‐mode HEMT amplifier achieved a high output power of 126 W at 2.5 GHz with improved distortion characteristics. This is the first report of an AlGaN/GaN E‐mode HEMT with an output power of over 100 W. (© 2009 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

A high-efficiency class-E GaN HEMT power amplifier at 1.9 GHz

A single stage class-E power amplifier in GaN high electron mobility transistor (HEMT) technology is reported. The circuit operates at 1.9 GHz. At 30-V drain bias, a power-added-efficiency (PAE) of 57% and a maximum output power of over 37dBm was achieved, corresponding to a power density of 5.25W/mm. At 40-V drain bias, an output power of 38.7dBm is achieved at 50% PAE corresponding to a power density of 7.4W/mm

Annealing temperature stability of Ir and Ni-based Ohmic contacts on AlGaN∕GaN high electron mobility transistors

Ti ∕ Al ∕ Ir ∕ Au Ohmic contacts on AlGaN∕GaN high electron mobility transistors (HEMTs) show promising electrical performance, with lower specific contact resistance than obtained with the more conventional Ti∕Al∕Ni∕Au metallization. HEMTs with both types of metallization have been measured up to 550°C. We find that the dc performance of devices with Ir-based contacts is significantly better at each temperature up to this maximum value, with higher transconductance (gm), saturated drain-source current (IDSS), and more stable threshold voltage (Vth). These contacts look very promising for HEMT power amplifier applications involving high temperature operation.

Effects of output harmonic termination on PAE and output power of AlGaN/GaN HEMT power amplifier

The authors experimentally investigate and discuss the effects of output harmonic termination on power added efficiency (PAE) and output power of an AlGaN/GaN high electron mobility transistor (HEMT) power amplifier (PA). The AlGaN/GaN HEMT PA with gate periphery of 1 mm was built and tested at L-band. Large-signal measurements and comparisons of the PAE and output power were carried out at different DC bias conditions from 50% of saturated drain current (I/sub dss/) to 1% of Id., for the PA with and without output harmonic termination. For class-AB operation at 25% of I/sub dss/, an increase of about 10% in peak PAE and 1 dBm in output power were observed in saturated output power range. Improvements of up to 9% in PAE and 1.2 dBm in output power were achieved over the measured DC bias conditions provided the output harmonics are properly terminated.