Comparison of Harmonic Balance Simulated and Measured Ultra-short Low Frequency/Microwave Transients in Pulse to Pulse Characterization of GaN transistors

Abstract

This paper describes, for the first time to our knowledge, a comparison of Pulse to Pulse (P2P) performances of an AlGaN/GaN HEMT obtained, experimentally on the one hand thanks to an on-wafer fully calibrated characterization system and on the other hand, from a Harmonic Balance (HB) simulation of a foundry-based model of the transistor. The measurements and the HB simulations allow the simultaneous and coherent extraction of, on the one hand, the complex envelopes of the microwave (RF) voltages and currents and, on the other hand, the Low Frequency (LF) drain current generated by the non-linearities of the measured/simulated components. The complex voltage and current envelopes at both ports of the Devices Under Test (DUT) and the LF drain voltage and current have been simultaneously measured/simulated with a periodic irregular radar burst excitations composed of ultra-short transient pulses. The main originality of this work lies in the fact that the generated RF time-domain waveforms used for the measured and simulated excitation of the transistors have been corrected to strongly reduce the emergence of the Gibbs phenomenon [1]. Lanczos/Fejér series have already been implemented in general-purpose simulator but, to our knowledge, this is the first time that they are directly used to generate a useful excitation signal in a microwave characterization system and in a HB simulation.