Electrothermal and trapping effects characterisation of AlGaN/GaN HEMTs

This paper presents a systematic analysis of the two kinds of traps encountered in AlGaN/GaN HEMTs. It is shown that passivation is very efficient to minimize the surface trap effects but has little effect on the buffer traps. Those ones can only be eliminated through the development of high purity substrates. Moreover thermal I-V and microwave behaviour of such transmissions is investigated through the use of a pulse-measurement system

Modelling of a 4-18GHz 6W flip-chip integrated power amplifier based on GaN HEMTs technology

This paper reports on the design of a cascode GaN HEMT distributed power amplifier demonstrating significant improvement of the best power performances reported to date. The active device is a 8x50µm AlGaN/GaN HEMT grown on siSiC. The distributed power amplifier integrates 4 cascode cells capacitively coupled to the gate line for power optimization. The active part made of the 4 cascode cells is implanted on a GaN-based wafer while the distributed passive part made of the interconnection lines is implanted on an AlN substrate. Finally, the GaN-based wafer integrating the active part is flip-chipped onto the AlN substrate via electrical and mechanical bumps. The flip-chip integrated circuit demonstrates a mean gain of 10dB and input/output matching lower than –10dB over the 4-18GHz bandwidth. At an input power of 29dBm (1db comp.), power simulations exhibit a mean output power of 37.6dBm with a standard deviation of 0.3dB, a power gain of 8.6dB and 16% of PAE over the band. At an input power of 31dBm (2dB comp.), the distributed amplifier achieves a mean output power of 38.6dBm, a power gain of 7.6dB and 18% of PAE

Large Signal Characterization of Microwave Power Devices

This paper presents an overview of nonlinear measurement techniques of microwave power devices and amplifiers. Several useful measurement techniques of nonlinear components available in Europe are described. Trends, especially in the area of high power and time domain measurements, are discussed. Finally, a summary of the TARGET measurement related tasks is proposed, in order to show how TARGET can improve the European capabilities in terms of nonlinear measurements

An electrothermal model for AlGaN/GaN power HEMTs including trapping effects to improve large-signal simulation results on high VSWR.

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A drain-Lag Model for AlGaN/GaN Power HEMTS

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A new nonlinear HEMT model for AlGaN/GaN switch applications

International audienceWe present here a new set of equations for modeling the IV characteristics of Field Effects Transistors (FETs), particularly optimized for AlGaN/GaN HEMTs. These equations describe the whole characteristics from negative to positive breakdown loci, and reproduce the current saturation at high level. Using this model enables to decrease the modeling process duration when a same transistor topology is used for several applications in a T/R module. It can even be used for switches design, which is the most demanding application in terms of IV swing. Moreover, particular care was taken to accurately model the first third orders of the current derivatives, which is important for multione applications. We also focused on an accurate definition of the nonlinear elements such as capacitances for power applications. There are 18 parameters for the main current source (and six for both diodes Igs and Igd). This can be compared to Tajima's equations-based model (13 parameters) or to the Angelov model (14 parameters), which only fit the IV characteristics for positive values of Vds. We will detail here the model formulation, and show some measurements/modeling comparisons on both IV, S-parameters and temporal load-pull obtained for a 8 75 m GaN HEMT, with 0.25 m gate length

Power Performance Evaluation of AlGaN/GaN HEMTs through Load Pull and Pulsed I-V Measurements

A systematic evaluation of power performances of AlGaN/GaN HEMTs has been performed by means of CW on wafer Load Pull measurements at X band. Those measurements have been correlated to the results obtained through I-V and S-parameters pulsed measurements and a strong correlation has been found between the two types of measurement. Power up to 6Watts has been measured on a 1.2 mm device that can be further improved if trapping effects can be removed. A non linear electrical model of the 0.25x 1200 µm² transistor taken from the I-V and the S-parameters pulsed measurements is validated by CW load pull measures

Spaceborne L Band High Efficiency 65W SSPA Demonstrator for Navigation and Radar Applications

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