Showing papers by "Giorgio Vannini published in 2013"
TL;DR: In this paper, a methodology for the characterization of the nonlinear dynamic behavior of electron devices (EDs) is presented, based on a complete and accurate ED characterization that is provided by large-signal low-frequency I/V measurements, performed by means of a low-cost setup, in conjunction with any model-based description of nonlinear reactive effects related to ED capacitances.
Abstract: A novel methodology for the characterization of the nonlinear dynamic behavior of electron devices (EDs) is presented. It is based on a complete and accurate ED characterization that is provided by large-signal low-frequency I/V measurements, performed by means of a low-cost setup, in conjunction with any model-based description of the nonlinear reactive effects related to ED capacitances. The unique feature of the proposed technique is that a fully harmonic control of waveforms at the current generator plane is achieved, and as a consequence, high-efficiency operation can be simply investigated. Different experimental data are presented on GaAs and GaN transistors, and to definitely verify the capability of the new approach, the design of a class-F GaN power amplifier is deeply investigated as a case study.
47 citations
Proceedings Article•
23 Dec 2013TL;DR: In this paper, a procedure to extract large-signal models for microwave transistors is discussed, where the model parameters are linked directly to experimental data to speed up the extraction procedure.
Abstract: This paper discusses a procedure to extract large-signal models for microwave transistors. By using experimental data, which not necessarily reflect the actual operating conditions, accurate large-signal models, suitable for CAD tools and working at high frequencies, can be obtained by combining direct extraction of basic parameters and numerical optimization. The idea consists of linking the model parameters directly to experimental data. In this way the extraction procedure is sped up. Examples of large-signal models for GaAs and GaN transistors are reported.
17 citations
TL;DR: In this paper, the impact of the dips in the impedance parameters on the behavior of the hybrid parameters for scaled GaAs HEMTs was analyzed. But the authors focused on the analysis of the dip in impedance parameters and not on the intrinsic capacitive core.
Abstract: The present study is focused on the analysis of the impact of the dips in the impedance parameters on the behavior of the hybrid parameters for scaled GaAs HEMTs. These dips turning into kink phenomena in the magnitude of the hybrid parameters consist of a sudden reduction of the magnitude of the impedance parameters at a given value of the frequency, due to the transition from a capacitive to an inductive behavior. A theoretical and experimental investigation is developed for determining the resonance frequency associated to such dips in terms of the equivalent circuit elements. The achieved formulas are exploited to propose a novel approach for the identification of the intrinsic capacitive core. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1237–1240, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27544
12 citations
02 Jun 2013
TL;DR: In this paper, an active bias tee suitable for small and large-signal low-frequency (5 Hz to 400 kHz) characterization of electron devices has been designed and manufactured, and different experimental results, carried out on 0.25 μm GaAs and GaN HEMTs, confirm the validity of the proposed bias circuit.
Abstract: An active bias tee suitable for small- and large-signal low-frequency (5 Hz to 400 kHz) characterization of electron devices has been designed and manufactured. Different experimental results, carried out on 0.25 μm GaAs and GaN HEMTs, confirm the validity of the proposed bias circuit.
12 citations
02 Jun 2013
TL;DR: In this article, a nonlinear model for microwave transistors is extracted from nonlinear measurements obtained by simultaneously driving the device under test with low and high-frequency excitations, and good agreement is obtained between model predictions and experimental data.
Abstract: In this work we describe a novel technique for the extraction of nonlinear model for microwave transistors from nonlinear measurements obtained by simultaneously driving the device under test with low- and high-frequency excitations. Specifically, the large-signal operating point of the device is set by large-signal low-frequency excitations. On top of these a tickle tone at high-frequency is applied. In this way, one can separate the contributions of the IDS current source and the charge sources by a single measurement. The nonlinear model, based on equations available in commercial CAD tools, is extracted for a 0.15 μm GaAs pHEMT. Good agreement is obtained between model predictions and experimental data.
10 citations
07 Jun 2013
TL;DR: In this article, a comparison between nonlinear and linear de-embedding procedures for the identification of the I/V dynamic characteristics at the transistor current-generator plane is presented, without the need for modeling device trapping and thermal effects.
Abstract: The manuscript presents a comparison between nonlinear and linear de-embedding procedures for the identification of the I/V dynamic characteristics at the transistor current-generator plane. These approaches, without the need for modeling device trapping and thermal effects, allow to retrieving the waveforms of the electrical quantities at the current generator that governs device performance in terms of output power and efficiency. It will be demonstrated that the accuracy of the selected procedure determines the accuracy of the obtained results. Simulations and measurements carried out on a 0.25 × 600 μm2 GaN HEMT are reported as case study.
3 citations
02 Jun 2013
TL;DR: In this article, an identification procedure for an FET analytical model oriented to μm and mm-wave applications is presented, based on low-frequency large-signal measurements to determine with a high level of accuracy the nonlinear current source parameters.
Abstract: In this paper an identification procedure for an FET analytical model oriented to μm- and mm-wave applications is presented. It is based on low-frequency large-signal measurements to determine with a high level of accuracy the nonlinear current source parameters. In addition, vector intermodulation measurements are used for the identification of the strictly nonlinear dynamic effects of the intrinsic device. As case study, the identification technique is applied to a 0.15-μm GaAs pHEMT. The extracted model is validated through comparison with nonlinear measurements carried out under conditions different from the ones used for model identification. A very good agreement with measurements has been achieved, despite the small number of data used to determine the model parameters.
2 citations
01 Oct 2013
TL;DR: In this article, the authors present a detailed and thorough investigation of the dips in the magnitude of the impedance parameters for AlGaAs/GaAs HEMTs, which can be attributed to the resonance between the extrinsic inductances and the intrinsic capacitances.
Abstract: The aim of this paper is to present a detailed and thorough investigation of the dips in the magnitude of the impedance parameters for AlGaAs/GaAs HEMTs. These dips should be attributed to the resonance between the extrinsic inductances and the intrinsic capacitances. As a consequence, the resonance frequencies associated to these dips can be analyzed to determine the intrinsic capacitances when the extrinsic inductances are known. To verify the validity of this straightforward approach, the extracted capacitances are compared with the results obtained with the conventional modelling method. The comparison is performed versus the gate-source voltage and the gate width.
1 citations
28 Oct 2013
TL;DR: In this article, a technique for the prediction of the optimum performance operation of GaN transistors is described, based on a small set of low-frequency measurements to acquire the I/V dynamic behavior of the device and a partial model to consider the strictly nonlinear dynamic effects.
Abstract: In this paper, a technique for the prediction of the optimum performance operation of GaN transistors is described. It is based on a small set of low-frequency measurements to acquire the I/V dynamic behavior of the device and a “partial” model to consider the strictly nonlinear dynamic effects of the device. The technique is applied and validated on a 0.5-8×250-μm2 GaN HEMT at 5.5 GHz.