Openings

PhD Positions

Stochastic microdosimetry applied to biomedical electromagnetics

Research Fields: microwaves, numerical modeling, electromagnetic dosimetry, exposure assessment, microscale characterization, electromagnetic cell and tissue models.

Research Laboratory: IETR / CNRS, Rennes, France.

Duration: 36 months, expected starting date is Oct. 2021.

Research project

Context

Wireless technologies operating in the upper part of the microwave spectrum are increasingly used for various applications. In particular, they have been used for high data rate communications [> 5 Gb/s], and 26-GHz / 60-GHz technologies are expected to be integrated in the near future in the next generation mobile systems (5G/ 6G, IoT, smart homes, human-centered communications). Besides, microwaves have a strong potential for numerous biomedical applications, including remote monitoring of wounds, non-invasive detection of glucose level, microwave imaging, thermal ablation, to list just a few. From the exposure assessment and control viewpoint, characterization of frequency-dependent electromagnetic power deposition at the sub-cellular level constitutes a new research challenge in the field of fundamental biomedical electromagnetics, with a potentially strong impact on the environmental safety and future biomedical applications.

Project overview

The main purpose of this PhD research project is to analyze micro-scale electromagnetic field and power distributions at sub-cellular level in order to gain an insight into local micro- and submm-scale phenomena occurring during exposure of the human body. Stochastic approach will be applied to account for the natural variability of physical parameters of biological cells.

The main research axes of this PhD project are threefold:

  1. Micro-scale numerical electromagnetic and transient thermal analysis will be performed on cellular models of progressively increasing complexity. To this end, we will consider simplified geometric models of a single cell with sub-cellular organelles and will increase the complexity to realistic stochastic single- and multi-cell models. Electromagnetic (complex permittivity and conductivity) and thermal (heat capacity and conduction) properties will be assigned to these models accounting for the stochastic variability. This will involve characterization of effective electromagnetic and thermal properties of cells and cellular sub-structures (membrane components, cytoplasm, cellular organelles, etc.).
  2. The electromagnetic field and absorbed power distributions will be computed using designed cellular models and appropriate numerical solvers (e.g. COMSOL, CST, SIM4LIFE). Stochastic multi-parametric analysis will be performed to assess the variability of the electromagnetic field and power distributions as a function of the geometry, complex permittivity, conductivity and micro-cellular environment. The data on micro-scale electromagnetic field and power deposition will be used as an input to thermal co-simulations.
  3. Finally, numerical results will be validated experimentally on cells using ad hoc metrological facilities and instrumentation of bioelectromagnetic platform of IETR (i.e. high-resolution dosimetry system based on infrared microscopy), with assistance from experts in cellular and molecular biology.

Research environment

The candidate will join the IETR laboratory of CNRS. Our research activities in biomedical electromagnetics cover a wide spectrum of fundamental and applied research spreading from multi-physics and multi-scale modeling to advanced technologies for body-centric wireless communications. The team was at the origin of pioneering innovations in biomedical electromagnetics, including the first millimeter-wave tissue-equivalent models, novel reflectivity based surface phantom concept, new broadband multi-physics characterization technique  for Debye-type materials, innovative millimeter-wave textile antennas for smart clothes, ultra-robust miniature implantable UHF antennas, and the first millimeter-wave reverberation chamber.

Candidate

We seek for highly engaged and motivated candidates with a MS or equivalent degree in electromagnetics, electrical engineering or electronics. The required skills and qualifications are:

  • Strong background in electromagnetics, analytical/numerical modeling, and microwave engineering. Knowledge in biomedical engineering / biophysics is welcome but not mandatory.
  • Knowledge of numerical modeling and experience with commercial or open-source numerical solvers (e.g. COMSOL, CST, SIM4LIFE), programming skills (e.g. MATLAB).
  • Fluency in English: the candidate should be conversant and articulate in English and must have strong writing skills. The successful candidate will be expected to present results of the work in high-profile journals and conferences. Knowledge of French is not required but would be appreciated.

Benefits

The qualified candidate will be part of a dynamic multidisciplinary team in an international, highly collaborative, and stimulating environment. He/she will have access to state-of-the-art laboratories, workshops, high-performance computing facilities, continuous training and receive a competitive salary.

In addition:

  • Approximately 7 weeks of annual leave per year + possibility of exceptional leave (moving home, etc.).
  • Generous statutory benefits: French national health coverage, unemployment allowances, retirement/pension funds, etc.
  • Possibility of subsidized meals, student housing, and partial reimbursement of public transport costs.
  • Location in one of the most attractive cities in France for professional and nonprofessional activities [entertainment, culture, sport, gastronomy, etc; 1:25 to Paris by train and 0:47 to a seaside].

Funding:              Full-time scholarship provided by the University of Rennes 1.

How to apply

To apply please send your applications to: Maxim Zhadobov (maxim.zhadobov@univ-rennes1.fr).

The application should consist of (in PDF format):

  • CV (incl. the contact details of two professional references [mail, address, position])
  • Motivation letter (incl. explanation relevance to this PhD research project and why the candidate believes he/she is suitable for the position)
  • Copy of PhD diploma
  • Reference letters (optional)

Antenna systems for wearable haptic devices for navigation assistance and biomedical monitoring

Summary

Wearable smart electronic devices offer compelling capabilities of monitoring physiological parameters and the environment of the user with subsequent data analysis and their representation by immediate haptic feedback. This interdisciplinary PhD project builds on a collaboration between the IETR laboratory of CNRS and the IRISA laboratory of Inria / CNRS (RAINBOW team). Expertise of IETR covers complex radiating systems and radars, bioelectronics, and bioelectromagnetics. Research at IRISA focuses on the fields from computer and network architecture to artificial intelligence, including software engineering, distributed systems, and virtual reality.

Background and Mission

Haptic feedback for wearables is receiving growing attention in consumer electronics, wireless biotelemetry of physiological parameters (e.g., heart and respiration rates, temperature, blood oxygen and glucose levels), and virtual reality applications. It is also a promising technology for assisting the visually impaired in navigating their surroundings, motion guidance for rehabilitation and physical training. A body-conformal wearable device can simultaneously monitor the vital signs and scan the environment using a radar to inform about surrounding objects and obstacles. The acquired information can be privately rendered to the user using an array of haptic actuators. Whereas both miniature biosensors and low-power radar technologies have sufficiently advanced in the recent years (allowing us to use off-the-shelf solutions), the flexible, robust, and reconfigurable on-body antenna arrays and corresponding RF circuits have not been proposed yet. In addition, the conformal antenna array has to be integrated with the array of haptic actuators while keeping the system light, compact, flexible, and robust to the environment (e.g., clothing, water, and small metallic objects).

The PhD candidate will work towards solving the aforementioned challenges. He/she will focus on the design of a body-conformal antenna array and RF circuit as well as their integration with of a wireless wearable haptic unit, which can be worn in a comfortable manner, including under clothing. Such device could be realized as, for instance, a flexible on-body patch that contains the antenna array and feeding network, haptic actuators (e.g., vibrotactile motors or skin stretch tactors), radar/sensor/communication units, and a rechargeable battery. To address the scientific and technical challenges, the successful candidate will have access to the interdisciplinary know-how of IETR in the field of complex radiating structures, radars, and bioelectronics as well as to the IRISA’s expertise in haptics and wearable interfaces. High-performance computing infrastructure and advanced numerical solvers will be used to handle computationally large multi-scale problems. State-of-the-art manufacturing and measurement facilities will help with the experimental characterization of the prototypes. The final wireless system will be tested on tissue-equivalent models as well in vivo through established collaborations of IETR. Finally, the successful candidate will be expected to present results of the work in high-profile journals and conferences.

Required Skills

— M.Sc. (or equivalent) degree.
— Competence in antenna and microwave engineering, miniaturized RF circuits and components; additional knowledge of radars and signal processing would be a plus.
— Experience with numerical electromagnetic solvers (e.g., COMSOL, CST, HFSS) and with measurement equipment incl. its operating principles (VNA, TDR, etc.).
— Fluency in English: the candidate should be conversant and articulate in English and must have strong writing skills. Knowledge of French is not required but would be appreciated.

Advantages

The qualified candidate will be part of a dynamic multidisciplinary team in an international, highly collaborative, and stimulating environment. He/she will have access to state-of-the-art laboratories, workshops, highperformance computing facilities, continuous training and receive a competitive salary.

In addition:
— approx. 7 weeks of annual leave per year + possibility of exceptional leave (moving home, etc.),
— generous statutory benefits: the French national health coverage, unemployment allowances, retirement/pension funds, etc.,
— possibility of subsidized meals, student housing, and partial reimbursement of public transport costs,
— location in one of the most attractive cities in France for professional and nonprofessional activities [entertainment and culture, sport, gastronomy, etc.]. Train connections: 1:25 to Paris and 0:47 to a seaside.
Funding: Full scholarship provided by the University of Rennes 1.
Possibility of funded international mobility (if eligible; require a separate application).
Duration: 36 months, expected starting date is Oct. 2021.
Location: Rennes, Region of Brittany, France. Laboratories IETR – CNRS (75%) and IRISA – Inria/CNRS (25%).

How to Apply

Please send your application to:
Dr. Denys Nikolayev (denys.nikolayev@univ-rennes1.fr)
Dr. Claudio Pacchierotti (claudio.pacchierotti@irisa.fr)
Dr. Maxim Zhadobov (maxim.zhadobov@univ-rennes1.fr)

Each application should consist of (PDF format):
— a CV (incl. publications),
— contact details of at least three professional references (mail, address, position),
— a motivation letter.

In the motivation letter, the applicant is encouraged to include the following details:
— an explanation of interest in the research we conduct and why he/she believes he/she is suitable for the position,
— short description of graduate projects,
— details of any relevant work experience.

 

Post-Doctoral Position

Near-field dosimetry for exposure assessment in 5G scenarios at millimeter waves

Context

This interdisciplinary project focuses on near-field millimeter-wave human exposure assessment applied to 5G networks. Interaction of 5G terminals with the human body not only affects the wireless performance of the system but requires careful consideration of user exposure to electromagnetic fields. This includes millimeter-wave exposure by wearable and mobile devices resulting in local absorption under near-field exposure conditions [1]. The existing dosimetry approaches—originally developed for 3G/4G networks operating in sub-6 GHz range—are not directly scalable to millimeter-waves. This motivates our research towards new solutions for accurate experimental dosimetry in 24 GHz and 60 GHz bands [2]. This project builds on the unique scientific and technical expertise of the IETR laboratory of CNRS in the fields of bioelectromagnetics and complex radiating systems.

Project overview

Existing experimental millimeter-wave dosimetry techniques are limited to electromagnetic field measurements using free-space probes in vicinity of wireless devices. These solutions do not account for the effects of the close vicinity to human body and therefore introduce significant error into estimated exposure levels. To overcome these limitations, we proposed an alternative approach based on a solid skin-equivalent model in the 60 GHz band [3]. This solid tissue-equivalent model will be used as a starting point to design a millimeter-wave dosimetry system prototype for measurements of the power density accounting for perturbation of the electromagnetic field radiated by a wireless device in presence of the human body. The project will mainly focus on development of an instrumented system that will integrate two key functionalities: (1) it will accurately reproduce the reflection coefficient from the human skin; (2) it will enable retrieval of the power density based on the field measurements inside the tissue-equivalent model.

1) A. Guraliuc, M. Zhadobov, R. Sauleau, L. Marnat, L. Dussopt.  Near-field user exposure in forthcoming 5G scenarios in the 60-GHz band. IEEE Transactions on Antennas and Propagation, 65(12), pp. 6606–6615, Dec. 2017.

2) M. Zhadobov, C. Leduc, A. Guraliuc, N. Chahat, R. Sauleau. Antenna / human body interactions in the 60 GHz band: state of knowledge and recent advances. Advances in Body-Centric Wireless Communication: Applications and State-of-the-art, IET, pp. 97 – 142, Jun. 2016.

3) A. R. Guraliuc, M. Zhadobov, O. De Sagazan, R. Sauleau. Solid phantom for body-centric propagation measurements at 60 GHz. IEEE Transactions on Microwave Theory and Techniques, 62(6), pp. 1373–1380, May 2014.

Research environment

The candidate will join the IETR laboratory of CNRS.  Our research activities in biomedical electromagnetics cover a wide  spectrum of fundamental and applied research spreading from  multi-physics and multi-scale modeling to advanced technologies for  body-centric wireless communications. The team was at the origin of  pioneering innovations in biomedical electromagnetics, including the  first millimeter-wave tissue-equivalent models, novel reflectivity based surface  phantom concept, new broadband multi-physics characterization technique  for Debye-type materials, innovative millimeter-wave textile antennas for smart  clothes, ultra-robust miniature implantable UHF antennas, and the first millimeter-wave reverberation chamber.

Candidate

We seek for highly engaged and motivated candidates with a PhD degree in electro­magnetics, electrical engineering or electronics. The required skills and qualifications are:

  • Strong background in electromagnetics, antenna design and microwave  engineering. Knowledge in electronics and / or bioelectromagnetics is welcome  but not mandatory.
  • Knowledge of numerical modeling and experience with commercial or open-source numerical solvers (e.g. CST, Ansys, SIM4LIFE); programming skills (e.g. MATLAB).
  • Fluency in English: the candidate should be conversant and articulate in English and must have strong writing skills. Knowledge of French is not required but would be appreciated.

How to apply

To apply please send your CV, motivation letter, reference letters (optional), and a copy of your PhD diploma to maxim.zhadobov@univ-rennes1.fr