Negative Conductance Load Modulation RF Power Amplifier

Neslen, Cody R

doi:10.15368/theses.2010.82

Cited by 3 publications

(7 citation statements)

References 9 publications

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“…Even with the reduction in efficiency, the maximum power efficiency of the tested prototype still exceeds that of some commercially-available mobile power amplifiers, which have efficiencies as low as 12% [7].…”

Section: Prototype 2 (Solderable Breadboard)mentioning

confidence: 83%

“…A previous attempt to implement this topology was unsuccessful, most likely due to the use of cascaded phase-shifting and voltage scaling networks which were highly sensitive to component variation and non-idealities, as well as the absence of harmonic termination [7].…”

Section: Prior Workmentioning

confidence: 99%

“…Summing of signals with varied amplitude and phase to form a high-PAPR signal. [7] have received a lot of attention. Excellent experimental results have been reported using the various device technologies and modulated signals, as summarized in Table 1.…”

mentioning

confidence: 99%

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Linear Power-Efficient RF Amplifier with Partial Positive Feedback

King

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Over the last decade, the number of mobile wireless devices on the market has increased substantially. New "multi-carrier" modulation schemes, such as OFDM, WCDMA, and WiMAX, have been developed to accommodate the increasing number of wireless subscribers and the demand for faster data rates within the limited commercial frequency spectrum. These complex modulation schemes create signals with high peak-to-average power ratios (PAPR), exhibiting rapid changes in the signal magnitude. To accommodate these high-PAPR signals, RF power amplifiers in mobile devices must operate under backed-off gain conditions, resulting in poor power efficiency. Various efficiency-enhancement solutions have been realized for backed-off devices to combat this issue.A brief overview of one of the more extensively researched solutions, the Doherty amplifier, is given, and its inherent limitations are discussed. A recently proposed amplifier topology that provides the efficiency benefits of the Doherty amplifier, while overcoming some of the fundamental problems that plague the standard Doherty architecture, is investigated. A step-by-step design methodology is presented and confirmed by extensive simulation in Agilent ADS. A design example, tuned for maximum efficiency at peak output power, is implemented on a PCB and tested to verify the validity of the proposed circuit configuration.iv ACKNOWLEDGMENTS I would first like to thank Dr. Vladimir Prodanov for the opportunity to work on such a fascinating and challenging project. Without his expertise in the field of amplifier design and his patience and willingness to spend long hours in the laboratory with me, the completion of this project would not have been possible.

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Section: Prototype 2 (Solderable Breadboard)mentioning

confidence: 83%

Section: Prior Workmentioning

confidence: 99%

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Linear Power-Efficient RF Amplifier with Partial Positive Feedback

King

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“…13 shows the actual "dead bug" implementation of the Prototype II circuit, which uses the three capacitor self-driven design to commutate the diff. pair 14.…”

mentioning

confidence: 99%

“…Commercial Top Level Schematic Summation of signals with varied amplitude and phase forming a high PAPR signal [13]. …”

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confidence: 99%

AC Power Combining Strategy with Application to Efficient Linear Power Amplifiers

Bendig¹

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With the ongoing push for wireless systems to accommodate more users and support higher data rates more efficient modulation schemes have been created that are more advanced than simple FM and AM modulation used for radio broadcasting. These modulation schemes, such as orthogonal frequency division multiplexing (OFDM), suffer from high peak to average power ratios. Standard Class A and Class AB amplifiers cannot simultaneously achieve good linearity and efficiency, and therefore there has been an increase in the development of new topologies to combat this issue. Common features to these circuits is power combining of two or more separate transistors. In this work, we consider various ways of two-source power combining and identify four topologies of interest. We notice that linear power-efficient amplifiers reported to date are based upon two of the identified combining strategies. We believe that no amplifiers have been reported that leverage the other two alternatives. This work produces a fully-functional amplifier based on one of these alternatives. The prototypes are intended to serve as concept verification of the architecture and hence are implemented at lower (1 MHz) frequencies.

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Combined Polar Codes and 2-12 QAM Applied to 5G Communications

Morais de Oliveira,

Melo Guedes Alcoforado,

Markarian

et al. 2023

JCIS

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The 5th generation of cellular communications systems (5G), standardized by the 3rd Generation Partnership Project (3GPP), uses polar codes in both physical download control channel (PDCCH) and physical download shared channel (PDSCH), combined with some low order modulations, such as QPSK and 16-QAM. Recently, 2-12-QAM modulation was proposed as an energy-efficient scheme when compared to 16-QAM. This article investigates the performance of a communication system using polar codes combined with a 2-12-QAM modulation scheme over channels disturbed by additive white Gaussian noise (AWGN) as well as over channels disturbed simultaneously by Rayleigh fading and AWGN. The 2-12-QAM modulation is compatible with legacy 16-QAM still widely used, and when combined with appropriate error correcting codes produces results that approach the Shannon limit.

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Negative Conductance Load Modulation RF Power Amplifier

Cited by 3 publications

References 9 publications

Linear Power-Efficient RF Amplifier with Partial Positive Feedback

Linear Power-Efficient RF Amplifier with Partial Positive Feedback

AC Power Combining Strategy with Application to Efficient Linear Power Amplifiers

Combined Polar Codes and 2-12 QAM Applied to 5G Communications

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