Bias and frequency dependence of FET characteristics

Parker, Anthony E.; Rathmell, James G.

doi:10.1109/tmtt.2002.807819

Cited by 39 publications

(18 citation statements)

References 9 publications

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“…However despite their differences, there are some common characteristics. One of them is the output conductance (gds) and transconductance (gm) frequency dispersion, considered as one of the causes for the memory effects which cause complexity in linearization [3]. In this paper we will call this effect "the frequency dispersion phenomena".…”

Section: Modelingmentioning

confidence: 99%

New methodology for modeling, design and implementation of RF power amplifiers

Rafael-Valdivia

Ballesteros

2017

J. Microw. Optoelectron. Electromagn. Appl.

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Abstract-This work presents a new methodology for modeling, design and implementation of power amplifiers in different technologies. As result of comparison, a flowchart with a new methodology is proposed which can be useful for the designer to design and implement power amplifiers with low, medium and high power devices in different technologies. This paper is divided in 4 parts: The first one is an introduction to the importance of modeling and design techniques in the final implementation of power amplifiers for the modern communication systems. The second one details the modeling process for different technologies, which final result is a unified model. The third part is related with the characterization of high power transistors, with special emphasis on substrate characterization and final implementation of a power amplifier. Finally, in the fourth part, the new methodology is proposed based on the comparisons of previous procedures.Index Terms-microwaves, modeling, power amplifier, substrate.I. INTRODUCTION Modern communication systems require RF power amplifiers to operate with large signal in broadband conditions. For 5G systems, requirements will be more demanding; and different technologies such as GaN and LDMOS are currently under investigation. Those two technologies have improved power density compared with traditional compounds semiconductors [1]. It originates problems with power dissipation which creates dispersion and thermal effects [2]. Consequently, for the design of RF power amplifiers using these semiconductors, it is essential to use accurate models that take into account these phenomena. Furthermore, for power amplifier implementation, an accurate substrate characterization is required, in order to get the appropriate input and output impedances for the matching networks. In this paper we will show that through the use of models flexible enough to predict static and dynamic conditions, and a one-port substrate characterization technique, we can demonstrate that it is possible to implement efficiently RF power amplifiers in LDMOS technologies. Based on those steps we propose a new methodology which is summarized in Fig. 1. That methodology will be explained in the following sections. Microwaves, Optoelectronics and Electromagnetic Applications, Vol. 16, No. 3, September 2017 GaAs is a promising technology for low power and linear applications; and GaN / LDMOS for high power amplifiers for long distance communications. As these 2 technologies behave differently, it makes sense to consider different strategies for modeling. However despite their differences, there are some common characteristics. One of them is the output conductance (gds) and transconductance (gm) frequency dispersion, considered as one of the causes for the memory effects which cause complexity in linearization [3]. In this paper we will call this effect "the frequency dispersion phenomena". We characterized this effect through I/V pulsed measurements by using the DIVA system provided by Accent Technologies [4]. T...

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Section: Modelingmentioning

confidence: 99%

New methodology for modeling, design and implementation of RF power amplifiers

Rafael-Valdivia

Ballesteros

2017

J. Microw. Optoelectron. Electromagn. Appl.

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“…There is no doubt that the significant dependence of the MESFET and HEMT I-V characteristics on frequency has played a major role in this situation. The inter-dependence between trapping effects and the thermal conditions of the device (whether they be through self-heating or ambient) has also added to the simulation difficulties [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

NONLINEAR MODELING OF TRAPPING AND THERMAL EFFECTS ON GaAs AND GaN MESFET/HEMT DEVICES

Chaibi¹,

Fernández

Mimouni³

et al. 2012

PIER

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Abstract-A novel nonlinear model for MESFET/HEMT devices is presented. The model can be applied to low power (GaAs) and high power (GaN) devices with equal success. The model provides accurate simulation of the static (DC) and dynamic (Pulsed) I-V characteristics of the device over a wide bias and ambient temperature range (from −70 • C to +70 • C) without the need of an additional electro-thermal sub-circuit. This is an important issue in high power GaN HEMT devices where self-heating and current collapse due to traps is a more serious problem. The parameter extraction strategy of the new model is simple to implement. The robustness of the model when performing harmonic balance simulation makes it suitable for RF and microwave designers. Experimental results presented demonstrate the accuracy of the model when simulating both the small-signal and largesignal behavior of the device over a wide range of frequency, bias and ambient temperature operating points. The model described has been implemented in the Advanced Design System (ADS) simulator to validate the proposed approach without convergence problems.

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“…For small-signal, narrowband signals of a frequency very-much greater than the time constants of trapping, it is not significant except for a slight shift in bias. However, the trapping time constants increase dramatically with drain potential, so they can affect signals in the microwave region at high drain potentials [2].…”

Section: Introductionmentioning

confidence: 99%

Characterization and modeling of substrate trapping in HEMTs

Rathmell

Parker

2007

2007 European Microwave Integrated Circuit Conference

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We present a novel and simple model of FET trapping based on a study of HEMTs using pulse techniques. This model accounts for the observed variation of extent of gate lag with bias and step potentials, and the variation of gate-lag time constant with drain potential. Because both charge capture and emission are accounted for, the model is appropriate for the simulation of both large-signal and small-signal dynamics. The model is verified by comparison with large-signal transient measurements and is consistent with small-signal gain measurements.

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Bias and frequency dependence of FET characteristics

Cited by 39 publications

References 9 publications

New methodology for modeling, design and implementation of RF power amplifiers

New methodology for modeling, design and implementation of RF power amplifiers

NONLINEAR MODELING OF TRAPPING AND THERMAL EFFECTS ON GaAs AND GaN MESFET/HEMT DEVICES

Characterization and modeling of substrate trapping in HEMTs

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