Research Laboratory:
Institut d’Electronique et des Technologies du numéRique (IETR), UMR CNRS 6164, Rennes, France.
Offer Type
PhD position (36 months scholarship)
Context
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 video streaming applications and cloud computing. The increasing need in high-performance mobile communications leads to a fast development of next- generation heterogeneous 5G/6G cellular mobile networks. The upper limit of the spectrum used for 5G has shifted towards the millimeter-wave (mmWave) band. In coming years, mmWave mobile broadband systems will be integrated in 5G/6G networks, in particular for the user access and backhaul / fronthaul links. In particular, transceivers operating in the 60–GHz band are expected to be integrated in user terminals; this allows for 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.
The new usages and services will involve interaction of radiating devices with the human body, both in terms of body impact on wireless device performance as well as in terms of user exposure to electromagnetic fields. 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 mmWaves. Proposing solutions for accurate dosimetry in the near- field 60 GHz scenarios is of uppermost importance to anticipate the deployment of 5G/6G networks.
Work description
Existing experimental mmWave dosimetry techniques are limited to electromagnetic field measurements using free-space probes in vicinity of wireless devices. These solutions do not account for a potential increase of exposure levels due to the presence of human body and may result in an underestimation of exposure levels [1]. To overcome these limitations, we propose a fundamentally new approach. It is based on a solid skin- equivalent model introduced by our research group in the 60-GHz band [2]. This model consists of a lossy 1.3
mm-thick dielectric layer (PDMS saturated with the carbon powder) and a metallic ground plane. The properties of the lossy dielectric (thickness, composition) are optimized to reproduce the reflection coefficient from human skin. This solid tissue-equivalent model will be used as a starting point to design a mmWave dosimetry system for measurements of the absorbed power density (APD) accounting for perturbation of the field radiated by a mmWave wireless device due to presence of the human body. The proposed system will integrate two key functionalities: (1) it will accurately reproduce the reflection coefficient of human skin and (2) it will enable accurate retrieval of the APD distribution. Various technical solutions will be explored. For example, an array of sensors can be integrated into the phantom and coupled to transmission lines printed on a low loss mmWave substrate through coupling slots etched in the ground plane. The main parameters of the system architecture will be optimized (lattice type and size of the antenna array) to maximize the field measurement accuracy and spatial resolution, while minimizing the complexity of the system. The experimental part of the PhD project will rely on the advanced numerical methods and state-of-the-art equipment and measurement facilities available at the IETR (anechoic chamber up to 500 GHz, near-field characterization, high-resolution 3D printing, multi-physics dosimetry, etc.).
Candidate
- Education: MS or equivalent.
- Background: electromagnetics, microwave design / measurements, numerical modeling. Knowledge in
- Electronics is welcome but not mandatory.
Contacts
To apply please send your CV, transcripts, motivation letter, and reference letters (optional) to :
- Dr.MaximZHADOBOV,CNRS(maxim.zhadobov@univ-rennes1.fr)
- Prof. Ronan SAULEAU, University of Rennes 1 (ronan.sauleau@univ-rennes1.fr)
More informations
English version here
French version here
