The determination of the transistor dynamic I-V characteristic from large signal RF measurements

Abstract

An analysis technique has been developed that allows for the determination of the transistor dynamic IN characteristics (RFI-V) directly from CW large signal RF measurements. A key feature of this technique is that R is performed under RF operation conditions similar to those found in power amplifiers under CW RF drive conditions. Investigations have shown that these dynamic RF I-Vs are independent of initial DC bias conditions and RF drive level for the MODFET structures investigated in this paper. These dynamic RF I-Vs can be directly compared with DC IVs to allow for the investigation of phenomena's like dispersion, RF breakdown and thermal effects etc.. To demonstrate their potential capability in the area of non-linear modelling these RF Ws have been used for non-linear parameter extraction of a relatively simple large signal model. A good comparison between the simulated and measured large signal behavior even for the higher harmonies has been achieved

Dynamic Large-Signal I-V Analysis and Non-Linear Modelling of Algan/Gan HEMTS

“…A microwave transition analyser was used to measure the magnitude and phase of the fundamental and four higher harmonics of transmitted and reflected signals, yielding the RF time domain waveform information and thus the RF large-signal transfer and output characteristics (5,6). Due to the above mentioned discrepancies between DC and RF operation, these dynamic experimental data appear to be more appropriate to be used for modelling purposes.…”

“…Due to the above mentioned discrepancies between DC and RF operation, these dynamic experimental data appear to be more appropriate to be used for modelling purposes. For this, a first attempt to apply a HEMT large-signal model, which describes the current source and non-linear capacitances by analytical equations (6,7), is presented finally. The transistor under investigation consisted of a Al(0.30)Ga(0.70)N/GaN (30nm/2µm) heterostructure with an additional GaN cap layer on top of the barrier, grown on sapphire substrate by metal organic vapour phase epitaxy.…”

Advanced large-signal modeling of GaN-HEMTs

“…results obtained by an extension of an existing large-signal model [6][7][8] to account for selfheating effects. Simulations are compared with DC and broadband S-parameter measurements for validation purposes.…”

“…Theoretical description of the large-signal model As a starting point for GaN HEMT modeling including self-heating, the analytical largesignal transistor model developed for GaAs HEMTs [6][7][8] has been chosen because of its simple model equations yet excellent non-linear modelling capabilities. This original model was implemented as a user-defined model in Agilent Advanced Design System (ADS) and has already been applied for AlGaN/GaN-HEMTs.…”