scholarly journals Asymmetric Doherty Power Amplifier with Input Phase/Power Adjustment and Envelope Tracking

Electronics ◽  
2021 ◽  
Vol 10 (19) ◽  
pp. 2327
Author(s):  
Fei Yang ◽  
Jun Li ◽  
Hongxi Yu ◽  
Sen Yan ◽  
Anxue Zhang ◽  
...  
Keyword(s):  
Power Amplifier ◽  
Dynamic Range ◽  
High Electron Mobility Transistors ◽  
Input Power ◽  
High Electron ◽  
Envelope Tracking ◽  
Electron Mobility Transistors ◽  
Power Adjustment ◽  
Doherty Power Amplifier ◽  
Load Pull

In this paper, the design and implementation of a Doherty power amplifier (DPA) are proposed using gallium nitride high electron mobility transistors (GaN HEMTs). Class-F and Class-C modes are combined to obtain an asymmetric DPA. The precise active load-pull controlling of fundamental and harmonic terminations of the DPA is simulated and analyzed, including the parasitics of the transistors. The measurements of the DPA with the phase difference, input power ratio adjustment, and envelope tracking of the auxiliary PA are discussed in detail in order to achieve a competitive performance. A greater than 63% drain efficiency is obtained within the 10-dB input power dynamic range at 2.1 GHz. The peak of the drain efficiency reaches 73%, with a corresponding output power of 46 dBm.

Optical Emission End-Point Detection for Via Hole Etching in InP and GaAs Power Device Structures

1993 ◽  
Vol 324 ◽  
Author(s):  
S. J. Pearton ◽  
F. Ren ◽  
C. R. Abernathy ◽  
C. Constantine
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Optical Emission ◽  
High Electron Mobility Transistors ◽  
Input Power ◽  
Bipolar Transistors ◽  
High Electron ◽  
Non Invasive ◽  
Electron Mobility Transistors ◽  
Via Holes ◽  
Point Detection

AbstractNarrow (∼30 μm ϕ) via holes have been etched in both InP and GaAs substrates using either C12/CH4/H2 /Ar or BC13/C12 discharges, respectively. High density (∼5×1011 cm−3), low pressure (1 mTorr for C12/CH4/H2/Ar or 15 mTorr for BC13/C12) conditions, combined with sidewall passivation obtained using AZ 4620 photoresist masks, produce the correct profiles for subsequent metallization to complete the via connection. Optical emission monitoring of the 417.2 nm Ga line during GaAs etching or of the 325.6 nm In line during InP etching provided a sensitive, non invasive and reliable indicator of endpoint for both types of substrates. The intensity of these lines was proportional to the microwave input power at fixed dc bias and pressure. The via holes are suitable for a range of InP and GaAs microwave power devices, including Heterojunction Bipolar Transistors and High Electron Mobility Transistors.

scholarly journals Electrical performances of AlInN/GaN HEMTs. A comparison with AlGaN/GaN HEMTs with similar technological process

2011 ◽  
Vol 3 (3) ◽  
pp. 301-309 ◽  
Author(s):  
Olivier Jardel ◽  
Guillaume Callet ◽  
Jérémy Dufraisse ◽  
Michele Piazza ◽  
Nicolas Sarazin ◽  
...  
Keyword(s):  
High Frequency ◽  
Continuous Wave ◽  
High Electron Mobility Transistors ◽  
High Electron ◽  
Power Added Efficiency ◽  
Electron Mobility Transistors ◽  
X Band ◽  
Gan Hemts ◽  
Load Pull ◽  
Interesting Alternative

A study of the electrical performances of AlInN/GaN High Electron Mobility Transistors (HEMTs) on SiC substrates is presented in this paper. Four different wafers with different technological and epitaxial processes were characterized. Thanks to intensive characterizations as pulsed-IV, [S]-parameters, and load-pull measurements from S to Ku bands, it is demonstrated here that AlInN/GaN HEMTs show excellent power performances and constitute a particularly interesting alternative to AlGaN/GaN HEMTs, especially for high-frequency applications beyond the X band. The measured transistors with 250 nm gate lengths from different wafers delivered in continuous wave (cw): 10.8 W/mm with 60% associated power added efficiency (PAE) at 3,5 GHz, 6.6 W/mm with 39% associated PAE at 10.24 GHz, and 4.2 W/mm with 43% associated PAE at 18 GHz.

High Electron Mobility Transistors with Optically Processed Refractory Silicide Metallizations: Thermal and Microwave Analysis

1991 ◽  
Vol 240 ◽  
Author(s):  
P. F. Tang ◽  
M. S. Fan ◽  
A. A. Illiadis
Keyword(s):  
High Temperature ◽  
Ohmic Contacts ◽  
Temperature Stability ◽  
High Electron Mobility Transistors ◽  
Input Power ◽  
Junction Temperature ◽  
High Electron ◽  
High Temperature Stability ◽  
High Electron Mobility ◽  
Electron Mobility Transistors

ABSTRACTThe enhanced high temperature gate metallizations consisting of sputtered TiWSi or TiWN were investigated in order to attain high temperature stability at temperatures in excess of 250°C. The TiWN/Au system resulted in a sheet resistance of only 11.5 mΩ/□ while TiWSi/Au resulted in 75.0 mΩ/□. The HEMTs and FETs processed with additional stable ohmic contacts of epitaxial Ge/Pd structures exhibited a stable transconductance of 160 -180 mS/mm at temperatures of 300°C. Thermal analysis indicated the peak junction temperature increase with an input power of 200mW to be less than 18°C at substrate temperature of 60°C.

AlGaN-Based Microwave Transmit and Receive Modules

2000 ◽  
Vol 622 ◽  
Author(s):  
John C. Zolper
Keyword(s):  
Power Density ◽  
Dynamic Range ◽  
High Electron Mobility Transistors ◽  
Material System ◽  
High Electron ◽  
High Current ◽  
Electron Mobility Transistors ◽  
Band Power ◽  
X Band ◽  
Great Progress

ABSTRACTAlGaN High Electron Mobility Transistors (HEMTs) have made great progress for solid state power amplifiers with the demonstration of an X-band power density up to 9.8 W/mm. This high power density is the result of the high current and voltage capability of this material system. Recently, it has also been shown that these devices can achieve low microwave added noise figures (NF = 0.6 dB at 10 GHz) while maintaining a large breakdown voltage (>60 V) and hence a large dynamic range. These results imply that AlGaN HEMTs can be used to perform the active transmit and receive functions in more robust, higher dynamic range modules. In this paper, the progress in AlGaN microwave HEMTs is reviewed and the issues related to AlGaN transmit and receive (T/R) modules are described.

scholarly journals Doherty Power Amplifier for LTE-Advanced Systems

Technologies ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 60 ◽  
Author(s):  
Abdulkhaleq ◽  
Yahya ◽  
Al-Yasir ◽  
Parchin ◽  
McEwan ◽  
...  
Keyword(s):  
Power Amplifier ◽  
Phase Measurement ◽  
Average Power ◽  
High Electron Mobility Transistors ◽  
Substrate Material ◽  
High Electron ◽  
Average Output ◽  
Load Impedance ◽  
Optimum Load ◽  
Doherty Power Amplifier

The design and implementation of an asymmetrical Doherty power amplifier are discussed, where two Cree GaN High Electron Mobility Transistors (HEMTs) devices are used for designing an asymmetrical Doherty power amplifier to achieve saturated power of 48 dBm and optimal back-off efficiency of 8 dB in the frequency band of 3.3–3.5 GHz. Rogers RO4350B material is used as a substrate material, a back-off of 8 dB was achieved with an average gain of 10 dB. Load-pull data are an important tool for determining the optimum load impedance that the transistor needs to see. Additionally, the measured efficiency was 50% when the designed amplifier was tested by a modulated signal of 8 dB peak-to-average-power ratio when the average output power was 40 dBm. At the same time, the linearity of the designed amplifier was measured and found 31.8 dB which can be improved using a digital pre-distorter. The gain phase measurement can be used as an indicator for compensating the phase difference between the two cells.

HVPE-GROWN AlGaN/GaN HEMTs

2003 ◽  
Vol 764 ◽  
Author(s):  
B. Luo ◽  
F. Ren ◽  
M. A. Mastro ◽  
D. Tsvetkov ◽  
A. Pechnikov ◽  
...  
Keyword(s):  
High Electron Mobility Transistors ◽  
Hydride Vapor Phase Epitaxy ◽  
Root Mean Square Roughness ◽  
High Electron ◽  
Electron Mobility Transistors ◽  
Current Collapse ◽  
Collapse Characteristics ◽  
Capacitance Voltage ◽  
Source Current ◽  
Measurement Area

AbstractHigh quality undoped AlGaN/GaN high electron mobility transistors(HEMTs) structures have been gorwn by Hydride Vapor Phase Epitaxy (HVPE). The morphology of the films grown on Al2O3 substrates is excellent with root-mean-square roughness of ∼0.2nm over 10×10μm2 measurement area. Capacitance-voltage measurements show formation of dense sheet of charge at the AlGaN/GaN interface. HEMTs with 1μm gate length fabricated on these structures show transconductances in excess of 110 mS/mm and drain-source current above 0.6A/mm. Gate lag measurements show similar current collapse characteristics to HEMTs fabricated in MBE- or MOCVD grown material.

IR Thermography for Temperature Measurements and Fault Location on AlGaN/GaN HEMTs and MMICs

2015 ◽  
Author(s):  
Lény Baczkowski ◽  
Franck Vouzelaud ◽  
Dominique Carisetti ◽  
Nicolas Sarazin ◽  
Jean-Claude Clément ◽  
...  
Keyword(s):  
Fault Location ◽  
Hot Spot ◽  
Life Time ◽  
High Electron Mobility Transistors ◽  
Junction Temperature ◽  
High Electron ◽  
Ir Thermography ◽  
Operating Life ◽  
Gan Hemt ◽  
Electron Mobility Transistors

Abstract This paper shows a specific approach based on infrared (IR) thermography to face the challenging aspects of thermal measurement, mapping, and failure analysis on AlGaN/GaN high electron-mobility transistors (HEMTs) and MMICs. In the first part of this paper, IR thermography is used for the temperature measurement. Results are compared with 3D thermal simulations (ANSYS) to validate the thermal model of an 8x125pm AIGaN/GaN HEMT on SiC substrate. Measurements at different baseplate temperature are also performed to highlight the non-linearity of the thermal properties of materials. Then, correlations between the junction temperature and the life time are also discussed. In the second part, IR thermography is used for hot spot detection. The interest of the system for defect localization on AIGaN/GaN HEMT technology is presented through two case studies: a high temperature operating life test and a temperature humidity bias test.

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