Linearity and Efficiency Characterization of AlGaN/GaN and InAlGaN/GaN HEMTs devices using Multi-tone Large Signal Measurements

In this paper, the linearity and efficiency of 2 different technologies of HEMT transistors (AlGaN/GaN and InAlGaN/GaN) has been performed using multi-tone large signal measurement in C-band. The transistors size is 8x50µm with 0.15µm gate length. This nonlinear characterization has been carried out using a multi-tone signal with a particularly property: it doesn't exist overlapping between the signal tones and all the third order intermodulation products (IM3) allowing to measure the C/I characteristic in few milliseconds. Moreover, the statistical properties of this signal (probability density function -PDF, Peak to Average Power Ratio -PAPR, …) can mimic those of complex modulation signals used in telecommunications (QAM, OFDM, …). To do that an Unequally Spaced Multi-Tone (USMT) test signal is generated by means of IQ modulated synthesiser. Note that the great interest of this signal is the lack of demodulator at reception which simplifies the C/I measurement. After measuring the DC characteristic of each device (IV, PIV, current leakage), the C/I, PAE, Gain and low frequency drain current of these HEMT transistor will be performed with a load-pull setup to reach the optimum load in terms of PAE.