A carrier-burst transmitter implementation: Design of bandpass filter and amplifier-BPF connection

The radio frequency carrier amplitude-burst transmitter constitutes a promising architecture capable of efficiently transmitting signals of highly demanding complex modulation schemes. However, the tested practical implementations present results that stay way behind the theoretically advanced promises. This study presents the first thorough study of the power efficiency and linearity characteristics that can be actually achieved with this architecture. The analysis starts with a brief revision of the theoretical idealised behaviour of these switched-mode amplifier systems, followed by the study of the many sources of impairments that appear in their real implementation. In particular, a special attention is paid to the dynamic load modulation caused by the often ignored interaction between the narrow-band signal reconstruction filter and the switched-mode power amplifier. The performance of this architecture is clearly explained based on the presented theory, which is supported by simulations and corresponding measurement results of a fully working implementation. The drawn conclusions allowed the development of a set of design rules for future improvements.

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“…A combline cavity BPF with 5.8 MHz BW, 450 MHz central frequency and 10 MHz of stop BW (44 dBc of attenuation) was selected [22].…”

Section: Experimental Validationmentioning

confidence: 99%

Radio frequency carrier amplitude‐burst transmitters – from architecture to circuit

Pires

Cabral

Pedro

2015

IET Microwaves, Antennas & Propagation

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“…Trace η TH depicts the theoretical drain efficiency curve of the circuit in Fig. 3 according to (5), while trace η D shows the simulation results for a modulation frequency of 20.7 MHz. It can be seen that both traces are in good agreement.…”

Section: Direct Filter Connectionmentioning

confidence: 99%

A source modulated amplifier in GaN designed for baseband PWM and direct filter connection

Seebacher

Schuberth

Singerl

et al. 2014

2014 IEEE International Black Sea Conference on Communications and Networking (BlackSeaCom)

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To cope with the increasing demand for bandwidth in wireless communications coding schemes with high crest factors are employed. As a result the power amplifier (PA) is operated far below maximum output power for most of the time, leading to low average efficiency in traditional designs. Therefore PA concepts providing efficiency enhancement in back off are key for efficient transmitters. Baseband PWM operated PAs in combination with direct filter connection are possible candidates. Due to the constant current of the used filters special PA structures are required. The proposed source modulated amplifier offers these properties. Its general operational principle is presented and an implementation study in a GaN MMIC process was carried out. The designed PA operates at 2.65 GHz delivering a maximum output power of 3W. To get optimum performance of the direct filter connection a codesign of the PA and the cavity filter included in the output matching network was performed, resulting in a compact solution.

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“…Note that due to the current continuity imposed by the band-pass filter, conduction losses occur during the on, Lc,on, and off, Lc,off, states of the envelope modulation. These were split as this allows one to inspect the impact of each period when the conduction is ensured by distinct devices, as is the case of the carrier [3] transmitters.…”

Section: Efficiency Modelmentioning

confidence: 99%

“…However, other topologies are gaining attention due to their high-efficiency potential, as well as applicability as frontends for digital radios. These include Class-E, Class-F or Class-D switched-mode power amplifier (SMPA) stages, driven by discrete amplitude modulations such as RF-pulsewidth modulation [2], carrier-burst [3], envelope delta-sigma modulation (EDSM) [4], [5], or bandpass delta-sigma modulation (BP-DSM) [6].…”

Section: Introductionmentioning

confidence: 99%

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Modeling efficiency of carrier amplitude burst wireless transmitter systems

Duarte

Pires

Cabral

et al. 2014

2014 International Workshop on Integrated Nonlinear Microwave and Millimetre-Wave Circuits (INMMiC)

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Despite the integrability and reconfigurability offered by fully digital wireless transmitters, their efficiency is still low, and no effective ways exist to diagnose and predict its degradation at higher back-off powers.Having found that it is the linear dependence of the switching losses with the output amplitude plus the inevitable constant losses that cause efficiency degradation at higher back-offs, an efficiency model was derived for carrier amplitude burst transmitter architectures. This model, not only allows the designer to predict the efficiency for a given modulation and output stage, but also allows one to identify the origin of the losses given an observed efficiency curve.

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A carrier-burst transmitter implementation: Design of bandpass filter and amplifier-BPF connection

Cited by 12 publications

References 7 publications

Radio frequency carrier amplitude‐burst transmitters – from architecture to circuit

Radio frequency carrier amplitude‐burst transmitters – from architecture to circuit

A source modulated amplifier in GaN designed for baseband PWM and direct filter connection

Modeling efficiency of carrier amplitude burst wireless transmitter systems

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