RF Circuit Design for Zero Energy Communication
Our ambition for 6G communication is to drastically reduce the Energy in IoT. For that purpose we aim at developing an integrated circuit enabling zero Energy communication.
The objective of this PhD is to design this circuit in FD-SOI and operating in the 2.4 GHz. In this PhD, we propose to use a new design technique which is currently revolutionizing the radio-frequency design. We expect that many innovations can be carried out during this PhD by combining those two innovations.
The candidate will integrate a large design team and he will participate in collaborative project at european level. As a first step, he will analyze the system constraints to choose the best architecture and derive the specifications. Then, he will formalize mathematically the performances of the backscattering technique in order to setup a design methodology. Then he will be working full time on circuit design, sending to fabrication two circuits in 22 um technology. He will be also involve in the test of the circuit as well as in the preparation of a demonstrator of the backscattering techniques. We expect to publish several papers in high level conferences.
Learning world models for advanced autonomous agent
World models are internal representations of the external environment that an agent can use to interact with the real world. They are essential for understanding the physics that govern real-world dynamics, making predictions, and planning long-horizon actions. World models can be used to simulate real-world interactions and enhance the interpretability and explainability of an agent's behavior within this environment, making them key components for advanced autonomous agent models.
Nevertheless, building an accurate world model remains challenging. The goal of this PhD is to develop methodology to learn world models and study their use in the context of autonomous driving, particularly for motion forecasting and developing autonomous agents for navigation.
Development of a predictive power model for a photovoltaic device under spatial constraints
CEA is developing new cell and module architectures and simulation tools to assess the electrical performance of photovoltaic (PV) systems in their operating environment. One of these models, called CTMod (Cell To Module), takes into account not only the different materials making up the module, but also the different cell architectures. For space applications, the community wants to use terrestrial silicon-based technologies that can be integrated on flexible PVAs (Photovoltaic Assembly). The space environment imposes severe constraints. A relevant evaluation of performance at the start and end of a mission is therefore essential for their dimensioning.
The aim of this thesis is to correlate physical models of radiation-matter degradation in space with electrical models of photovoltaic cells. Performance degradations linked to the various electron, proton and ultraviolet (UV) irradiations of the space environment will be evaluated and validated experimentally. Linked to the CTMod Model, this new approach, never seen in the literature, will able to get a more accurate understanding of interactions between radiations and PVAs. These degradations result from non-ionizing energy deposition phenomena, quantified by the defect dose per displacement, and ionizing ones quantified by the total ionizing dose for protons and electrons. In the case of UV, the excitation of electrons in matter generates chain breaks in organic materials and colored centers in inorganic materials. Initially, the solar cell used in the model will be a Silicon cell, but the model can be extended to include other types of solar cell under development, such as perovskite-based cells.
Multiphe hydrogen injection at anode side of PEMFC
The alternating feeding architecture (known as Ping-Pong) was developed by the CEA. This architecture emerged in 2013 and has been implemented in several fuel cell systems. Following the latest tests on this architecture, questions remained unanswered. First, it is a question of understanding how species (hydrogen, nitrogen, liquid and gaseous water) move in cells operating with alternating feeding. Control laws influences these movements, it will be necessary to identify the levers to make the most out of it and then to propose methods to promote the evacuation of water and nitrogen while avoiding the evacuation of hydrogen.
The thesis work will aim to optimize the anode architecture with alternating feeding and to bring this architecture to maturity. The key points are the search for an optimum control of this architecture, the achievement of a hydrogen rejection rate of less than 1%. Finally, this optimization will also have to maximize the durability of the stack.
The doctoral student will have to model the movements of species at different time scales (10ms to 10 minutes), understand the mechanisms, adapt the control laws and validate the new control laws on a test bench.
This work will identify solutions to efficiently evacuate liquid water and nitrogen and minimize H2 rejection and then obtain superior performance compared to conventional architectures.
Mesure de la réponse intra-pixel de détecteur infrarouge à base de HgCdTe avec des rayons X pour l’astrophysique
In the field of infrared astrophysics, the most commonly used photon sensors are detector arrays based on the HgCdTe absorbing material. The manufacturing of such detectors is a globally recognized expertise of CEA/Leti in Grenoble. As for the Astrophysics Department (DAp) of CEA/IRFU, it holds renowned expertise in the characterization of this type of detector. A key characteristic is the pixel spatial response (PSR), which describes the response of an individual pixel in the array to the point-like generation of carriers within the absorbing material at various locations inside the pixel. Today, this detector characteristic has become a critical parameter for instrument performance. It is particularly crucial in applications such as measuring galaxy distortion or conducting high-precision astrometry. Various methods exist to measure this quantity, including the projection of point light sources and interferometric techniques. These methods, however, are complex to implement, especially at the cryogenic operating temperatures of the detectors.
At the DAp, we propose a new method based on the use of X-ray photons to measure the PSR of infrared detectors. By interacting with the HgCdTe material, the X-ray photon generates carriers locally. These carriers then diffuse before being collected. The goal is to derive the PSR by analyzing the resulting images. We suggest a two-pronged approach that integrates both experimental methods and simulations. Data analysis methods will also be developed. Thus, the ultimate objective of this thesis is to develop a new, robust, elegant, and fast method for measuring the intra-pixel response of infrared detectors for space instrumentation. The student will be based at the DAp. This work also involves collaboration with CEA/Leti, combining the instrumental expertise of the DAp with the technological knowledge of CEA/Leti.
Development and characterization of a reliable 13.5 nm EUV OAM carrying photon beamline
The Extreme UltraViolet (EUV) photon energy range (10-100 nm) is crucial for many applications spanning from fundamental physics (attophysics, femto-magnetism) to applied domains such as lithography and nanometer scale microscopy. However, there are no natural source of light in this energy domain on Earth because photons are strongly absorbed by matter, requiring thus vacuum environment. People instead have to rely on expensive large-scale sources such as synchrotrons, free electron lasers or plasmas from large lasers. High order laser harmonic generation (HHG), discovered 30 years ago and recognized by the Nobel Prize in Physics in 2023, is a promising alternative as a laboratory scale EUV source. Based on a strongly nonlinear interaction between an ultrashort intense laser and an atomic gas, it results in the emission of EUV pulses with femto to attosecond durations, very high coherence properties and relatively large fluxes. Despite intensive research that have provided a clear understanding of the phenomenon, it has up to know been mostly limited to laboratories. Breaching the gap towards applied industry requires increasing the reliability of the beamlines, subjects to large fluctuations due to the strong nonlinearity of the mechanism, and developing tools to measure and control their properties.
CEA/LIDYL and Imagine Optic have recently joined their expertise in a join laboratory to develop a stable EUV beamline dedicated to metrology and EUV sensors. The NanoLite laboratory, hosted at CEA/LIDYL, is based on a high repetition rate compact HHG beamline providing EUV photons around 40eV. Several EUV wavefront sensors have been successfully calibrated in the past few years. However, new needs have emerged recently, resulting in the need to upgrade the beamline.
The first objective of the PhD will be to install a new HHG geometry to the beamline to enhance its overall stability and efficiency and to increase the photon energy to 92eV, a golden target for lithography. He will then implement the generation of a EUV beam carrying orbital angular momentum and will upgrade Imagine Optic’s detector to characterize its OAM content. Finally, assisted by Imagine Optic engineers, he will develop a new functionality to their wavefront sensors in order to enable large beam characterization.
Secure and Agile Hardware/Software Implementation of new Post-Quantum Cryptography Digital Signature Algorithms
Cryptography plays a fundamental role in securing modern communication systems by ensuring confidentiality, integrity, and authenticity. Public-key cryptography, in particular, has become indispensable for secure data exchange and authentication processes. However, the advent of quantum computing poses an existential threat to many of the traditional public-key cryptographic algorithms, such as RSA, DSA, and ECC, which rely on problems like integer factorization and discrete logarithms that quantum computers can solve efficiently. Recognizing this imminent challenge, the National Institute of Standards and Technology (NIST) initiated in 2016 a global effort to develop and standardize Post-Quantum Cryptography (PQC). After three rigorous rounds of evaluation, NIST announced its first set of standardized algorithms in 2022. While these algorithms represent significant progress, NIST has expressed an explicit need for additional digital signature schemes that leverage alternative security assumptions, emphasizing the importance of schemes that offer shorter signatures and faster verification times to enhance practical applicability in resource-constrained environments. Building on this foundation, NIST opened a new competition to identify additional general-purpose signature schemes. The second-round candidates, announced in October 2024, reflect a diverse array of cryptographic families.
This research focuses on the critical intersection of post-quantum digital signature algorithms and hardware implementations. As the cryptographic community moves toward adoption, the challenge lies not only in selecting robust algorithms but also in deploying them efficiently in real-world systems. Hardware implementations, in particular, must address stringent requirements for performance, power consumption, and security, while also providing the flexibility to adapt to multiple algorithms—both those standardized and those still under evaluation. Such agility is essential to future-proof systems against the uncertainty inherent in cryptographic transitions. The primary objective of this PhD research is to design and develop hardware-agile implementations for post-quantum digital signature algorithms. The focus will be on supporting multiple algorithms within a unified hardware framework, enabling seamless adaptability to the diverse needs of evolving cryptographic standards. This involves an in-depth study of the leading candidates from NIST’s fourth-round competition, as well as those already standardized, to understand their unique computational requirements and security properties. Special attention will be given to designing modular architectures that can support different signatures, ensuring versatility and extensibility. The proposed research will also explore optimizations for resource efficiency, balancing trade-offs between performance, power consumption, and area utilization. Additionally, resilience against physical attacks (side-channel attacks and fault injection attacks) will be a key consideration in the design process. This PhD project will be conducted within the PEPR PQ-TLS project in collaboration with the TIMA laboratory (Grenoble), the Agence nationale de la sécurité des systèmes d’information (ANSSI) and INRIA.
Distributed Passive Radar
Our objective is to detect and locate drones entering an urban area to be protected by observing the signals emitted by cellular stations. Studies have shown that it is possible to locate a drone if it is close to the listening system and the cellular station (i.e. the base station). When the situation is more complex (i.e. there is no direct path between the cellular station and the radar or in the presence of several transmitting cellular stations causing a high level of interference), a single listening system called passive radar cannot correctly detect and locate the drone. To overcome these difficult conditions, we wish to distribute or deploy in the area to be protected a set of low-complexity passive radars which optimally exploit the signals emitted by these cellular stations. A distribution and deployment strategy for passive radars must then be considered by taking into account the positions of the transmitting cellular stations. The possibility of exchanging information between passive radars must also be considered in order to better manage interference linked to cellular stations.
For high-performance, safe, and long-lasting batteries: understanding the role of an additive in liquid electrolytes
The trade-off between performance, aging, and safety remains a major challenge for Li-ion batteries [1]. Indeed, the incorporation of certain additives into the 3rd-generation electrolyte aims to delay or reduce the consequences of thermal runaway, thus reducing the risk of fire or explosion. However, this approach can have negative effects on other key parameters, such as ionic conductivity [2,3]. Therefore, this thesis proposes to study the coupled effects of these additives in order to better understand and potentially predict their impact on each of these indicators.
At the beginning of this work, an additive will be selected to study its role in an NMC 811/Gr-Si chemistry and a 3rd-generation liquid electrolyte, in terms of performance, long-term stability, and safety. The additive will be chosen based on the state of the art and post-mortem analysis of commercial cells representative of the current market. In parallel, new commercial cells of a few Ah will be used. These will be equipped with a reference electrode, internal temperature measurement, and ionic conductivity monitoring. The cells will then be activated with the selected electrolyte at different additive concentrations. Electrochemical performance, along with chemical and morphological characterization of the materials present, will be studied. Key safety parameters (thermal stability, release of reducing gases, O2, released energy, flammability of the electrolyte) for these new cells will be measured at different additive concentrations. The internal instrumentation, including the reference electrode, will also be used innovatively to study the onset of thermal runaway under these conditions.
A full aging campaign will be conducted over a maximum period of one year. At regular intervals, a sample of cells will be studied to characterize the impact of aging on chemical, electrochemical, and morphological changes, as well as on key safety parameters. The most important mechanisms, along with simplified laws governing safety as a function of additive quantity and aging, will be proposed.
[1] Batteries Open Access Volume 9, Issue 8, August 2023, Article number 427
[2] Journal of Energy Storage 72 (2023) 108493
[3] Energy Storage Materials 65 (2024) 10313