Linearization of power amplifiers by second harmonics and fourth-order nonlinear signals
01 Feb 2013-Microwave and Optical Technology Letters (Wiley Subscription Services, Inc., A Wiley Company)-Vol. 55, Iss: 2, pp 425-430
TL;DR: In this article, a single-stage power amplifier and two-way Doherty amplifier are linearized by the technique that uses second harmonics and fourth-order nonlinear signals.
Abstract: In this article, a single-stage power amplifier and two-way Doherty amplifier are linearized by the technique that uses second harmonics and fourth-order nonlinear signals. Measurements of the linearization effects on the third- and fifth-order intermodulation products have been carried out. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:425–430, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27294
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TL;DR: In this paper, the effects of an interstage capacitor related to the power-added efficiency of a power amplifier were analyzed numerically, and the inter-stage capacitor between the driver and power stages was removed to improve the overall efficiency.
Abstract: In this work, we analyzed numerically the effects of an interstage capacitor related to the power-added efficiency of a power amplifier. In particular, we calculated the power consumption values induced by the on-resistances and short-circuit current of the class-D-type driver-stage. After analyzing the results, the interstage capacitor between the driver and the power stages was removed to improve the overall efficiency. By removing the interstage capacitor, the supply voltage for the driver stage can be decreased compared to a normal power amplifier. The power consumption at the on-resistance of the driver stage can be reduced and the power consumption induced by the short-circuit current can be reduced. Additionally, we measured the power consumption at the driver stages to verify the calculated results. In the experimental results, we noted improved efficiency of the proposed amplifier, while its output power was nearly identical to that of a normal amplifier. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2479–2484, 2013
5 citations
TL;DR: In this paper, the linearization of broadband power amplifier for application in the 0.9-1.3 GHz frequency range is considered, and the effects of linearization are considered for the case of two sinusoidal signals separated in frequency by different intervals up to 80 MHz, ranging input power levels to saturation.
Abstract: The linearization of broadband power amplifier for application in the
frequency range 0.9-1.3 GHz is considered in this paper. The amplifier is
designed for LDMOSFET characterized by the maximum output power 4W designing
the broadband lumped element matching circuits and matching circuits in
topologies that combines LC elements and transmission lines. The
linearization of the amplifier is carried out by the second harmonics of the
fundamental signals injected at the input and output of the amplifier
transistor. The effects of linearization are considered for the case of two
sinusoidal signals separated in frequency by different intervals up to 80 MHz
ranging input power levels to saturation. [Projekat Ministarstva nauke
Republike Srbije, br. TR-32052]
4 citations
Cites methods from "Linearization of power amplifiers b..."
...The experimental verification of the linearization method was performed on a standard narrowband amplifier at 1 GHz for two cases: when the linearization signals are led only at the output of the amplifier transistor and when linearization signals are simultaneously inserted at the input and output of the amplifier transistor [3]....
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TL;DR: This paper represents, for the first time, the linearisation method of RF power amplifiers, which is based on using the second- and fourth-order nonlinear signals shaped by digital signal processing in a baseband domain.
Abstract: This paper represents, for the first time, the linearisation method of RF power amplifiers, which is based on using the second- and fourth-order nonlinear signals shaped by digital signal p...
4 citations
01 Oct 2015
TL;DR: In this paper, a broadband RF power amplifier operating at frequency range 0.75 GHz to 1.25 GHz is linearized by the even-order nonlinear signals at frequencies around the second harmonics that are inserted at the amplifier transistor gate and drain throughout the broadband matching circuits that provide high amplifier efficiency as well as adequate power level of the injected signal for the linearization.
Abstract: In this paper a broadband RF power amplifier operating at frequency range 0.75 GHz to 1.25 GHz is linearized by the even-order nonlinear signals at frequencies around the second harmonics that are inserted at the amplifier transistor gate and drain throughout the broadband matching circuits that provide high amplifier efficiency as well as adequate power level of the injected signal for the linearization. The effects of the transistor input (gate) second harmonic impedance on the amplifier efficiency is examined in addition to the analysis of the influence of the output (drain) second harmonic impedance performed earlier. The amplifier linearization is carried out for two-tone test characterized by different frequency interval between signals up to 100 MHz for various signal power levels as well as for WCDMA digitally modulated signal.
3 citations
01 Jul 2017
TL;DR: The linearization approach that exploits the modified baseband signal is applied in this paper to linearize a two-way broadband Doherty power amplifier for quadrature amplitude modulated signals characterized with frequency spacing between spectral components up to 30 MHz for different input power levels.
Abstract: The linearization approach that exploits the modified baseband signal is applied in this paper to linearize a two-way broadband Doherty power amplifier. The required linearization signal formed as a product of the second-order nonlinearity of a nonlinear system is adequately processed in amplitude and phase in the digital domain. Then, the fundamental carrier second harmonic is modulated by the tuned baseband signal and injected to the input and output of the carrier amplifier transistor in the Doherty configuration. The assessment of the linearization technique effects is considered on a two-way Doherty amplifier for quadrature amplitude modulated signals characterized with frequency spacing between spectral components up to 30 MHz for different input power levels. Additionally, impact of the linearization method is tested on the WCDMA digitally modulated signal.
3 citations
References
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TL;DR: The authors' simulations show that a version of the lens operating at the frequency of visible light can be realized in the form of a thin slab of silver, which resolves objects only a few nanometers across.
Abstract: Optical lenses have for centuries been one of scientists’ prime tools. Their operation is well understood on the basis of classical optics: curved surfaces focus light by virtue of the refractive index contrast. Equally their limitations are dictated by wave optics: no lens can focus light onto an area smaller than a square wavelength. What is there new to say other than to polish the lens more perfectly and to invent slightly better dielectrics? In this Letter I want to challenge the traditional limitation on lens performance and propose a class of “superlenses,” and to suggest a practical scheme for implementing such a lens. Let us look more closely at the reasons for limitation in performance. Consider an infinitesimal dipole of frequency v in front of a lens. The electric component of the field will be given by some 2D Fourier expansion,
10,974 citations
TL;DR: In this paper, a fully matched N-way Doherty amplifier with two-, three-, and four-way structures is presented. And the linearity performance of the Doherty amplifiers is optimized for better efficiency versus linearity by a bias adjustment of the peaking amplifiers.
Abstract: This paper presents a new fully matched N-way Doherty amplifier. The basic principles of operation and important features are described. For the experimental verification, 2.14-GHz Doherty amplifiers having two-, three-, and four-way structures are implemented using silicon LDMOSFETs and tested using down-link WCDMA signal. The linearity performances of the two-, three-, and four-way Doherty amplifiers are optimized for better efficiency versus linearity by a bias adjustment of the peaking amplifiers. For simultaneously improving the efficiency and linearity to achieve maximum efficiency versus linearity, the gate biases of the peaking amplifiers for the N-way Doherty amplifier are optimized. As a result, the efficiency versus linearity characteristics are drastically improved by N-way extension of the Doherty amplifier.
267 citations
14 Oct 2005
TL;DR: In this article, the authors provide comprehensive theoretical treatment of periodic structures based on general electro-magnetic theory and provide a theoretical basis for periodic structures applicable to photonic crystals in optical to microwave regions.
Abstract: Provides comprehensive theoretical treatment of periodic structures based on general electro -magnetic theory Presents the original work of the authors, all recognized experts in their fields Builds a theoretical basis for periodic structures applicable to photonic crystals in optical to microwave regions Progresses smoothly and logically from analytical to numerical to computational approaches Illustrates the discussion with more than 250 figures and 1000 equations
204 citations
17 Jan 2005
TL;DR: In this paper, a high-power Doherty amplifier using a single push-pull LDMOS field effect transistor is proposed as the main amplifier of a feed-forward linear amplifier for wideband code-division multiple access (W-CDMA) base-station applications.
Abstract: This paper presents a RF high-power Doherty amplifier for improving the efficiency of a 30-W feedforward linear amplifier used in wide-band code-division multiple-access (W-CDMA) base-station applications. A high-power Doherty amplifier using a single push-pull LDMOS field-effect transistor is proposed as the main amplifier of a feedforward linear amplifier. The peaking amplifier's compensation line and gate bias effects are analyzed at the 6-dB backoff point. From the experimental results of a forward-link one-carrier W-CDMA, a 2.2% power-added efficiency improvement at an adjacent channel leakage power ratio linearity of -60 dBc is achieved in comparison to a conventional feedforward class-AB amplifier.
125 citations
"Linearization of power amplifiers b..." refers methods or result in this paper
...The simulated DE for the ideal case without substrate losses is in accordance with the expected values for the standard two-way Doherty [8, 11]....
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...The various linearization methods have been applied to Doherty amplifier to reduce the nonlinear distortions while keeping the efficient mode, such as postdistortion-compensation [7], the feedforward linearization technique [8], the predistortion linearization technique [9], and combination of those two linearization techniques [10]....
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...Agilent Advanced Design System (ADS) software has been used for the design of conventional two-way Doherty amplifier in standard configuration [7, 8, 10, 11], which schematic diagram is shown in Figure 5....
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TL;DR: In this paper, the authors discussed the improvement in the third-order intermodulation product (IM3) performance obtainable from RF and microwave amplifiers by two alternative injection techniques.
Abstract: This paper discusses the improvement in the third-order intermodulation product (IM3) performance obtainable from RF and microwave amplifiers by two alternative injection techniques. The first is the addition to the amplifier input of the second harmonics of the input spectrum and the second is the addition to the amplifier input of the difference frequencies between the spectral components of the input signal. Both techniques are considered in theory, by simulation and in practice. Both techniques give useful improvements in two-tone IM3 performance. The second harmonic technique reduced the IM3 level by 43 dB in an amplifier at 835 MHz. The difference-frequency technique gave a reduction of 48 dB in an amplifier at 880 MHz. The difference-frequency technique also gives a greater improvement for complex spectra signals.
121 citations