Openings

Post-Doctoral Position

Integrated Antennas for Efficient Data Transfer and Powering of Implanted in Body Devices

  • Research Fields

Biomedical telemetry, miniature antennas, conformal antennas, implantable wireless devices, in-body communications, through-body transmission

  •  Research environment

The Post-Doctoral Researcher will join Electromagnetic Waves in Complex Media (WAVES, www.ietr.fr/spip.php?article1616) Team of the IETR. 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 mm-wave tissue-equivalent phantoms, novel reflectivity based surface phantom concept, new broadband multi-physics characterization technique for Debye-type materials, innovative mm-wave textile antennas for smart clothing, ultra-robust miniature implantable UHF antennas, first mm-wave reverberation chamber.

  • Scientific project

Wireless implantable, ingestible, and injectable in-body devices offer breakthrough possibilities for biomedical telemetry, telemedicine, and neural interfacing. Biotelemetry allows for continuous monitoring of various physiological parameters in clinical research and in medicine, where it can be used for disease prevention and treatment. Neural interfacing makes it possible to study the brain, restore sensory function, and assist in the rehabilitation of amputees, survivors of paralysis, and patients with neurodegenerative diseases. Advanced microelectromechanical systems, integrated circuits, and microfluidics continuously drive innovation in both fields. Wireless powering and recharge substantially extend the lifespan of wireless implants and help to avoid surgery for replacing batteries.

Establishing a robust medium- to long-range (i.e. 5–20 m) link between an in-body device and external equipment remains a major challenge. This is mainly due to low radiation efficiencies (η < 0.1%) of in-body antennas operating in lossy media and in part due to impedance detuning issues caused by uncertain electromagnetic properties of body tissues. Considering typical maximum input power levels ranging from several up to about 50 mW (limited by safety standards) and receiver sensitivities, this provides a line-of-sight operating range only up to several meters. Moreover, even an intrinsically isotropic in-body antennas becomes directive due to their radiation not only attenuating but also diffracting and scattering while propagating through highly heterogeneous human body.

The main goal of this post-doctoral project is to conduct a multi-disciplinary study on development, optimization, and characterization of robust and efficient multi-band antenna systems for implantable biotelemetry and telemedicine devices. In particular, the candidate will investigate and analyze the antenna–tissue decoupling mechanisms, design robust multi-band antennas (target frequency bands are mainly 403 MHz, 434 MHz, 1.4 GHz, and 2.45 GHz) with improved radiation efficiency. Finally, we aim to develop new characterization methods for such antenna systems involving far-field and experimental dosimetry techniques. A prototype of the system will be fabricated and experimentally validated in close collaboration with the industrial and academic research partners.

  • References

D. Nikolayev, M. Zhadobov, P. Karban, R. Sauleau. Electromagnetic radiation efficiency of body-implanted devices. Physical Review Applied, 9(2), pp. 024033(12), Feb. 2018.

D. Nikolayev, M. Zhadobov, P. Karban, R. Sauleau. Conformal antennas for miniature in‐body devices: the quest to improve radiation performance. Radio Science Bulletin, 363, pp. 52-64, Dec. 2017.

D. Nikolayev, M. Zhadobov, R. Sauleau, P. Karban. Antennas for ingestible capsule telemetry. State-of-the-Art in Body-Centric Wireless Communications and Associated Applications, IET, pp. 143 – 186, Jun. 2016.

  • Candidate

Education: PhD degree or equivalent.

Background: electromagnetics, antenna design, numerical modeling, microwave measurements. Knowledge in biology / medicine is welcome but not mandatory.

The candidate should have less than 3 years of experience after the PhD defense and should not previously work at the IETR.

  • Timeline

Duration: 12 months, potentially renewable

Starting date: between 01/01/2019 and 01/03/2019

  • How to apply

To apply please send your CV, motivation letter, reference letters (optional), and a copy of your PhD diploma to

Maxim ZHADOBOV, CNRS Researcher (maxim.zhadobov@univ-rennes1.fr)


Post-Doctoral Position

Near-Field Exposure Assessment in Emerging 5G Scenarios

Key words: Millimeter-wave antennas and systems, electromagnetic modeling, experimental dosimetry, 60-GHz band, tissue modeling, microwave measurements.

  • Background

Continuous development of mobile terminals, such as smart phones, tablets, body-worn devices, has increased the wireless data traffic, which will keep growing due to the video streaming applications and cloud computing. The increasing need in high-performance mobile communications leads to a fast development of next generation heterogeneous 5G cellular mobile networks. The upper limit of the spectrum used for 5G wireless networking has shifted towards the millimeter-wave (MMW) band. By 2020, MMW mobile broadband systems will be integrated in 5G networks, in particular for the user access and backhaul / fronthaul applications. In particular, the 60–GHz transceivers (i.e. 57–66 GHz in Europe) are expected to be available in user terminals, thus offering a larger channel bandwidth, higher data rates (beyond several Gb/s), high level of security for short-range communications, and low interference with adjacent cells. These new usages and services will involve interaction of radiating devices with the human body, both in terms of body impact on wireless device performances as well as in terms of user exposure. This includes near-field exposure by wearable and mobile devices operating in vicinity of the human body. Radiated powers of the user terminals may result in locally very high exposure levels under near-field exposure conditions due to localized absorption at MMW. In this context, accurate dosimetry in the near-field scenarios in V band (50–75 GHz) is of uppermost importance.

  • Objectives

This Post-Doctoral research project will deal with open challenges related to experimental near-field dosimetry in the 60 GHz band. In particular, it will focus on development of a prototype for accurate near-field dosimetry accounting for a potential increase of exposure levels due to presence of human body.

The main steps of the research project are:

  1. Design and opti mization of the near-field dosimetry system in V band.
  2. Numerical analysis and calibration of the system.
  3. Fabrication of a proof-of-concept prototype and experimental validation.
  • Candidate

Education: PhD or equivalent.

Background: electromagnetics, numerical modeling, microwave / thermal measurements.

  • Timeline

Duration: 12 months, potentially renewable

Starting date: between 01/01/2019 and 01/03/2019

  • Contacts

To apply please send your CV, motivation letter, and reference letters (optional) to:

Maxim ZHADOBOV (maxim.zhadobov@univ-rennes1.fr)

Prof. Ronan SAULEAU (ronan.sauleau@univ-rennes1.fr)


MS project

Computational electromagnetics applied to hybrid modeling of personalized brain stimulation in the kHz range

Context

Brain stimulation is a technique consisting in inducing changes in brain activity, mainly using electric or magnetic fields delivered invasively (intracranial) or non-invasively (scalp electrodes). The main applications of brain stimulation are diagnostic and therapeutic. In the case of epilepsy, a disease with a prevalence of approx. 60 millions of patients worldwide, a third of patients are drug-refractory (> 150 000 in France), and are therefore left of therapeutic options. For those patients, brain stimulation could represent an alternative. However, the brain stimulation protocols that have been investigated so far are mostly empirical, with little guidance from neurophysiological and biophysical consideration, and lack of mechanistic understanding, which is a major roadblock to provide novel therapeutic solutions to epileptic drug-refractory patients. Here, we propose a hybrid approach combining an accurate control of the electromagnetic fields associated with brain stimulation and realistic dynamics of the neuronal networks close to the electrode.

Objective

To analyse numerically the electromagnetic field distribution in brain thus contributing to development of a new tool for realistic modeling of neuronal activity during brain stimulation in the kHz range.

Work program

The research project proposes a hybrid approach consisting in (1) detailed electromagnetic dosimetry using numerical anatomical models of brain, coupled with (2) biologically grounded computational models of neurons generating epileptiform activity on the other hand. This hybrid approach will offer individualized stimulation parameters optimizing the electric field and current induced in brain tissue, in terms of spatial extent, magnitude and dynamics. Electromagnetic field inside brain induced by electrodes used for brain stimulation will be modeled using numerical solvers (CST and / or SEMCAD & SIM4LIFE). To this end, numerical electromagnetic models of the human body of increasing complexity will be employed to accurately simulate the electric field distribution in brain.

Candidate

We are looking for a candidate with a background in electromagnetics and numerical modeling at the Master level or last year of Engineering School. Experience in biomedical engineering is welcome but not mandatory. The intern will join a multidisciplinary team consisting of research scientists in electromagnetics, signal processing, and electrophysiology. The student will be hosted by IETR www.ietr.fr and will work in collaboration with LTSI www.ltsi.univ-rennes1.fr.

Contact

To apply please send your CV, motivation letter, and transcripts to

Maxim Zhabodov (CNRS Researcher, IETR)   maxim.zhadobov@univ-rennes1.fr

Practical information: application deadline Feb. 15, 2019; starting date March 1, 2019; around 570 €/month.