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High-power Amplifiers (high-power + amplifier)

Distribution by Scientific Domains
Engineering80%

Selected Abstracts

Model order reduction of linear and nonlinear 3D thermal finite-element description of microwave devices for circuit analysis

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 5 2005
Raphaël Sommet
Abstract Electrothermal models of power devices are necessary for the accurate analysis of their performances. For this reason, this article deals with a methodology to obtain an electrothermal model based on a reduced model of a 3D thermal finite-element (FE) description for its thermal part and on pulsed electrical measurements for its electrical part. The reduced thermal model is based on the Ritz vector approach, which ensures a steady-state solution in every case. An equivalent SPICE subcircuit implementation for circuit simulation is proposed and discussed. An extension of the method to a nonlinear reduced model based on the Kirchoff transformation is also proposed. The complete models have been successfully implemented in circuit simulators for several HBT or PHEMT device structures. Many results concerning devices and circuits are presented, including simulation of both the static and dynamic collector-current collapse in HBTs due to the thermal phenomenon. Moreover, the results in terms of the circuit for an X-band high-power amplifier are also presented. As for the nonlinear approach, results concerning an homogeneous structure is given. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005. [source]

An adaptive predistorter using modified neural networks combined with a fuzzy controller for nonlinear power amplifiers

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 1 2004
Hong-min Deng
Abstract In digital radio systems, high data transmission rates require the use of spectrally efficient linear modulation techniques; however, these techniques are generally sensitive to nonlinearity caused by the high-power amplifier (HPA) employed in transmitter systems. The nonlinearity of HPA is potentially responsible for spectral spreading, adjacent channel interference (ACI), and degradation of bit-error rates (BERs). This article proposes an adaptive predistortion scheme to compensate for the HPA's nonlinearity by combining adaptive structure-varying neural networks and a fuzzy controller. Simulations show that this predistortion scheme can very effectively prevent the warping of the signal constellations, thus reducing the system's BER and learning time. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14: 15,20, 2004. [source]

Thermal analysis of multi-finger GaInP collector-up heterojunction bipolar transistors with miniature heat-dissipation packaging structures

INTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 1 2010
Pei-Hsuan Lee
Abstract We build up a finite element modeling (FEM) approach to analyze the thermal performance of collector-up (C-up) heterojunction bipolar transistor (HBTs) with a heat-dissipation via configuration. Highly compact heat-dissipation packaging structures of GaInP/GaAs C-up HBTs have been designed and evaluated systematically. In this work, we devise the 2-D and 3-D models to simulate the actual devices and to investigate the temperature distribution behavior. Results from 2-D model indicate that the large heat-dissipation via configuration can be further reduced by 29% to meet the requirement of HBT-based small high-power amplifiers (HPAs) for the cellular phones. Furthermore, the demonstrated results show that the maximum temperature within the collector calculated from 3-D model is lower than that from 2-D model. In the 3-D analysis, it is revealed that the configuration can be reduced by 32%. Therefore, thinning the heat-dissipation via constructed underneath the GaInP/GaAs C-up HBT should be helpful for miniaturization of HBT-based HPAs in future mobile communication systems. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Behavioral modeling of GaN-based power amplifiers: Impact of electrothermal feedback on the model accuracy and identification

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2009
Roberto Quaglia
Abstract In this article, we discuss the accuracy of behavioral models in simulating the intermodulation distortion (IMD) of microwave GaN-based high-power amplifiers in the presence of strong electrothermal (ET) feedback. Exploiting an accurate self-consistent ET model derived from measurements and thermal finite-element method simulations, we show that behavioral models are able to yield accurate results, provided that the model identification is carried out with signals with wide bandwidth and large dynamics. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2789,2792, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24732 [source]

GaN/AlGaN HEMT hybrid and MMIC microstrip power amplifiers on s.i. SiC substrate

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3 2006
R. Quay
Abstract This work presents very recent examples for the realization of high-power amplifiers for both communication and solid-state radar applications based on AlGaN/GaN HEMTs on s.i. SiC substrate. Broadband power amplifiers for mobile communication base stations between 0.9 and 2.7 GHz are presented. Microstrip line X-frequency band power amplifiers provide pulsed output power levels of 10 W with 16 dB of gain at 9 GHz. This work further shows improved device reliability results at VDS = 30 V and 200 °C channel temperature for gate lengths of 300 nm. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]