Thesis (M/F): Design of microwave power amplifiers

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Vacancy

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Description

PhD thesis: Design of high-efficiency power amplifiers optimized in EVM with current and future modulation schemes for radar and radio applications.

Working context

Future radiocommunication systems will use high-efficiency spectral modulations and high peak power ratios (IPPs) to ensure high data rates while having the lowest possible energy footprint. This observation directly impacts the design of power amplifiers by imposing a compromise between the following 3 criteria: linearity, efficiency and output power. Until now, the design of the amplifiers has been carried out with a CW excitation and a circuit simulation such as Harmonic Balance (Harmonical Balance). Validation with modulated excitation signals is done a posteriori with system simulation with behavioral model and measurement; it is then difficult to refine the design with these results in the presence of realistic signals.
The main objective of this work is to propose a new design procedure to take into account linearity metrics such as EVM and ACPR in the design process. This can be done using a specific multi-tone harmonic equilibrium simulation technique developed at XLIM which makes it possible to simulate non-linear circuits with modulated signals and to obtain linearity metrics during the design procedure. The amplifier obtained is then designed and optimized in terms of linearity, efficiency and output power.
The calendar of thesis will be as follows:
- Bibliography concerning modulated signals (definitions, generation, characteristics)
- Simulation DC, AC and HB CW of the GaAs FET and/or GaN HEMT (Power limits) transistor model
- Theoretical study of the bases concerning the design of power amplifiers
- Design of a narrow bandwidth power amplifier
- Introduction to the generation of modulated signals in circuit simulation software
Simulation of non-linear transistors controlled with circuit-modulated signals
- Drafting of a thesis dissertation
- Thesis defence
This thesis will be carried out within the framework of the “Priortal Research Programmes and Equipment (PEPR) - France 2030” in a project called “Network of the Future - Beyond the 5G Millimeter Onwading, Antennas and RIS” (PC4: NF-YACARI ). The standardization of 5G by 3GPP is now well advanced, with the release of releases 15 (2018) and 16 (2020). Version 17 is almost complete but has been delayed due to the pandemic and version 18 is in its very first phase. In this context, French research and development must remain involved and even become a major player in the pursuit of 5G and the networks of the future (beyond 5G, 6G).
The alliance of the Institut Mines-Télécom, CEA and the CNRS within a research programme will accelerate this strategy and guarantee national sovereignty in the digital field.
One of the main developments in 5G is the introduction of new spectrum fragments in the millimeter wave frequency bands (mmWave) (20 to 52.6 GHz). While millimeter bands are traditionally considered for point-to-point bonds, 3GPP 5GNR has paved the way for the use of millimeter bands. This spectrum offers a high-capacity wireless wireless transmission potential of data rates of several gigabits per second (Gbps). Early deployments of 5G focus mainly on the band below 6 GHz and the use of mmWave technology should be a key factor for the evolution of 5G. Despite the wide potential of available bandwidth, mmWave signal transmissions suffer from fundamental technical challenges such as severe travel losses, blocking sensitivity, cost and energy consumption of radio frequency (RF) transceivers.
The aim of the project is to propose innovative solutions at all levels, from antenna systems to signal processing by integrating circuits on advanced technologies to mature millimetre technology and make it compatible with the technical and societal requirements of tomorrow.
Particular attention is paid to the design of energy-optimised systems at the level of circuits, antenna systems and signal processing. The project brings together 12 institutional partners and 30 technical contributions.

The item is in a sector of the protection of scientific and technical potential (PPST), and therefore requires, in accordance with the regulations, that your arrival be authorised by the competent authority of the SREM.

Responsibilities

Constraints and risks

The post is located in a sector under the Protection of Scientific and Technical Potential (PPST), and therefore requires, in accordance with the regulations, that your arrival be authorized by the competent authority of the Ministry of Higher Education for Research.

Qualification

Additional information

Future radiocommunication systems will use high-efficiency spectral modulations and high peak power ratios (IPPs) to ensure high data rates while having the lowest possible energy footprint. This observation directly impacts the design of power amplifiers by imposing a compromise between the following 3 criteria: linearity, efficiency and output power. Until now, the design of the amplifiers has been carried out with a CW excitation and a circuit simulation such as Harmonic Balance (Harmonical Balance). Validation with modulated excitation signals is done a posteriori with system simulation with behavioral model and measurement; it is then difficult to refine the design with these results in the presence of realistic signals.
The main objective of this work is to propose a new design procedure to take into account linearity metrics such as EVM and ACPR in the design process. This can be done using a specific multi-tone harmonic equilibrium simulation technique developed at XLIM which makes it possible to simulate non-linear circuits with modulated signals and to obtain linearity metrics during the design procedure. The amplifier obtained is then designed and optimized in terms of linearity, efficiency and output power.
The calendar of thesis will be as follows:
- Bibliography concerning modulated signals (definitions, generation, characteristics)
- Simulation DC, AC and HB CW of the GaAs FET and/or GaN HEMT (Power limits) transistor model
- Theoretical study of the bases concerning the design of power amplifiers
- Design of a narrow bandwidth power amplifier
- Introduction to the generation of modulated signals in circuit simulation software
Simulation of non-linear transistors controlled with circuit-modulated signals
- Drafting of a thesis dissertation
- Thesis defence
This thesis will be carried out within the framework of the “Priortal Research Programmes and Equipment (PEPR) - France 2030” in a project called “Network of the Future - Beyond the 5G Millimeter Onwading, Antennas and RIS” (PC4: NF-YACARI ). The standardization of 5G by 3GPP is now well advanced, with the release of releases 15 (2018) and 16 (2020). Version 17 is almost complete but has been delayed due to the pandemic and version 18 is in its very first phase. In this context, French research and development must remain involved and even become a major player in the pursuit of 5G and the networks of the future (beyond 5G, 6G).
The alliance of the Institut Mines-Télécom, CEA and the CNRS within a research programme will accelerate this strategy and guarantee national sovereignty in the digital field.
One of the main developments in 5G is the introduction of new spectrum fragments in the millimeter wave frequency bands (mmWave) (20 to 52.6 GHz). While millimeter bands are traditionally considered for point-to-point bonds, 3GPP 5GNR has paved the way for the use of millimeter bands. This spectrum offers a high-capacity wireless wireless transmission potential of data rates of several gigabits per second (Gbps). Early deployments of 5G focus mainly on the band below 6 GHz and the use of mmWave technology should be a key factor for the evolution of 5G. Despite the wide potential of available bandwidth, mmWave signal transmissions suffer from fundamental technical challenges such as severe travel losses, blocking sensitivity, cost and energy consumption of radio frequency (RF) transceivers.
The aim of the project is to propose innovative solutions at all levels, from antenna systems to signal processing by integrating circuits on advanced technologies to mature millimetre technology and make it compatible with the technical and societal requirements of tomorrow.
Particular attention is paid to the design of energy-optimised systems at the level of circuits, antenna systems and signal processing. The project brings together 12 institutional partners and 30 technical contributions.

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