A highly efficient chireix amplifier using adaptive power combining

Qureshi, Jawad; Liu, R.; Graauw, A.J.M. de; Heijden, Mark P. van der; Gajadharsing, John; Vreede, L.C.N. de

doi:10.1109/mwsym.2008.4632943

Cited by 12 publications

(18 citation statements)

References 2 publications

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“…However, when considering practical amplifier implementations, the output stages are loaded by the parasitic shunt conductance of the output devices itself, as well as by the losses in the matching networks and power combiner, yielding a degradation of the efficiency attainable under load modulation. This efficiency degradation will be most pronounced in power backoff, yielding a deviation of the ideal efficiency curves [15]. Consequently, the selection of the optimum compensation angle must also be adjusted.…”

Section: Selection Of the Optimum Compensation Angle When Output Lmentioning

confidence: 99%

“…The drawbacks to this approach are the high input power required and a low effective gain that will be achieved in power backoff operation due to this constant input amplitude. As result, the power-added efficiency (PAE) will drop rapidly in power backoff since it is dependent on the RF input power [15]. To improve the PAE, one can make use of the fact that most devices act more like a power-dependent current source than an ideal voltage source.…”

Section: Input Signal Generationmentioning

confidence: 99%

“…The parasitic output conductance of the branch amplifiers can be approximated by a conductance connected in parallel with the load [15] with a value given by (15) where is the load conductance seen by the devices when the outphasing angle is equal to zero. By using the relation between normalized output voltage and outphasing angle (Section III-A), the load conductance can be expressed as (16) The decrease of efficiency due to the parasitic conductance depends on the ratio of parasitic output conductance to the load conductance, which increases with outphasing [15], yielding the equation (17) where represent the parasitic output conductance.…”

Section: Appendix Amentioning

confidence: 99%

“…1(a)] have been steadily improved over the last few years. Reported results include outphasing amplifier implementations using DPD [10], outphasing amplifiers with input-power control and differential-phase adjustment for enhanced efficiency performance [11]- [14], as well outphasing amplifier implementations that feature combinations of input power and phase control with adaptive output-susceptance compensation to enhance the efficiency in power backoff operation [15]. In spite of these promising results, to the authors' knowledge, truly high-power high-efficiency outphasing amplifiers that yield competitive industrial implementations have not yet been brought to light.…”

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confidence: 99%

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A 90-W Peak Power GaN Outphasing Amplifier With Optimum Input Signal Conditioning

Qureshi

Pelk

Marchetti

et al. 2009

IEEE Trans. Microwave Theory Techn.

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116

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Abstract-A 90-W peak-power 2.14-GHz improved GaN outphasing amplifier with 50.5% average efficiency for wideband code division multiple access (W-CDMA) signals is presented. Independent control of the branch amplifiers by two in-phase/quadrature modulators enables optimum outphasing and input power leveling, yielding significant improvements in gain, efficiency, and linearity. In deep-power backoff operation, the outphasing angle of the branch amplifiers is kept constant below a certain power level. This results in class-B operation for the very low output power levels, yielding less reactive loading of the output stages, and therefore, improved efficiency in power backoff operation compared to the classical outphasing amplifiers. Based on these principles, the optimum design parameters and input signal conditioning are discussed. The resulting theoretical maximum achievable average efficiency for W-CDMA signals is presented. Experimental results support the foregoing theory and show high efficiency over a large bandwidth, while meeting the linearity specifications using low-cost low-complexity memoryless pre-distortion. These properties make this amplifier concept an interesting candidate for future multiband base-station implementations.Index Terms-Base station, high-efficiency RF power amplifier, mixed-mode amplifier, outphasing amplifier, wideband code division multiple access (W-CDMA).

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Section: Selection Of the Optimum Compensation Angle When Output Lmentioning

confidence: 99%

Section: Input Signal Generationmentioning

confidence: 99%

Section: Appendix Amentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

A 90-W Peak Power GaN Outphasing Amplifier With Optimum Input Signal Conditioning

Qureshi

Pelk

Marchetti

et al. 2009

IEEE Trans. Microwave Theory Techn.

Self Cite

116

View full text Add to dashboard Cite

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“…Recent attempts to design voltage-mode Class-D GaN PAs can be found in the literature [107,108]. However, most realizations of GaN outphasing PAs are currently based on saturated Class-B [101,109] or on Class-F PAs [110][111][112], with consequent sub-optimal efficiency curve.…”

Section: The Voltage Source Issuementioning

confidence: 99%

High Efficiency Power Amplifiers for Modern Mobile Communications: The Load-Modulation Approach

et al. 2017

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Abstract:Modern mobile communication signals require power amplifiers able to maintain very high efficiency in a wide range of output power levels, which is a major issue for classical power amplifier architectures. Following the load-modulation approach, efficiency enhancement is achieved by dynamically changing the amplifier load impedance as a function of the input power. In this paper, a review of the widely-adopted Doherty power amplifier and of the other load-modulation efficiency enhancement techniques is presented. The main theoretical aspects behind each method are introduced, and the most relevant practical implementations available in recent literature are reported and discussed.

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Modified LINC transmitter using efficient parallel amplification scheme

Liu

Schreurs

Raedt

et al. 2011

Micro & Optical Tech Letters

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and the curve of the laser temperature tracking are shown in Figure 3(b). CONCLUSIONSWe have shown that a CW-clock transfer is possible over several 100-meters long links using affordable and commercially available telecom-grade optical and RF components achieving an extremely low-added timing jitter and high long-term stability. Group-delay variations of the RF signal in the presented clock-distribution system are compensated by the laser-wavelength tuning and the exploitation of the chromatic dispersion of the optical fibers in the forward and backward direction. Besides our fully compensated and filtered clock-distribution scheme, we believe that our outstanding results are also due to the excellentquality, mass-produced electrical and optical components that became available recently: (1) microwave and optoelectronic components: monolithic gain blocks with stable gain, monolithic mixers with excellent balance and offset used as phase detectors, integrated PIN-FET modules with repeatable performance and (2) mass-produced optical fiber to very tight specifications including PMD. Although PMD effects were not compensated in our system, we experimentally confirmed that all fiber tolerances including PMD are tight enough to allow almost perfect tracking in an inexpensive fiber pair, a much cheaper solution than using a single fiber together with fiber couplers, circulators and/or Faraday mirrors. ACKNOWLEDGMENTSThis work was supported by Instrumentation Technologies d.d., Slovenia, Sincrotrone Trieste S.C.p.A., Italy, and Ministry of Higher Education, Science and Technology of the Republic of Slovenia under the research program P2-0246. The authors are grateful to V. Poucki and M. Predonzani for help with long-term measurements and data acquisition.

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A highly efficient chireix amplifier using adaptive power combining

Cited by 12 publications

References 2 publications

A 90-W Peak Power GaN Outphasing Amplifier With Optimum Input Signal Conditioning

A 90-W Peak Power GaN Outphasing Amplifier With Optimum Input Signal Conditioning

High Efficiency Power Amplifiers for Modern Mobile Communications: The Load-Modulation Approach

Modified LINC transmitter using efficient parallel amplification scheme

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