PhD position: Influence of the periodicity of all-dielectric networks on the diffusion/absorption trade-off in a multi-static threat context

19 Feb 2024
Job Information

Organisation/Company

Universite de Brest

Research Field

Physics » Electronics
Other

Researcher Profile

First Stage Researcher (R1)

Country

France

Application Deadline

3 Jun 2024 - 23:59 (Europe/Paris)

Type of Contract

Temporary

Job Status

Full-time

Offer Starting Date

1 Oct 2024

Is the job funded through the EU Research Framework Programme?

Not funded by an EU programme

Is the Job related to staff position within a Research Infrastructure?

No

Offer Description

Context and problem

Traditionally, electromagnetic (EM) absorbers have been optimized to ensure strong specular absorption within a limited angular range. However, due to the rapid development of threats related to the emergence of multi-static radars, it is necessary to reconsider the perspective from which EM absorbers are approached. In this context, radars (transmitter/receiver) can be located anywhere in space and exchange information among themselves.

In a conventional context, absorbers are designed to ensure optimal absorption (S11 < -10 dB) within a limited angular range (typically -30° to +30°). However, this approach poses a risk of significantly degrading their performance for high incidence angles. In the broader context of multi-static scenarios, this strategy can prove counterproductive as the target may be detected by the radar network with transmitters/receivers positioned at highly oblique angles.

Hence, the main objective of this thesis project is to establish new performance criteria within this general context and to develop global optimization strategies. The thesis will explore the multiple scattering and absorption capabilities of periodic networks of lossy materials. Indeed, in highly periodic networks (D > λ0 ), higher-order Floquet modes with non-specular reflection (reflection angle different from the incident angle) can be excited. This concept has been significantly explored in the field of PCB-based metasurfaces for beam steering or multiple scattering applications. However, the exploration of these possibilities in 3D absorbers has been limited, and even less attention has been given to studying the compromise between absorption and non-specular reflection in the context of multi-static scenarios. 

Preliminary work in the team has shown that exploiting these non-specular reflection modes can optimize both specular absorption and the total energy backscattered by the periodic surface [1]. Currently, this trade-off is primarily examined for a single incidence and polarization at a specific frequency. However, it is important to recognize that this concept is inherently broadband and less dependent on polarization, opening up a broader perspective.

 

Research axes and thesis progress

The thesis will firstly focus on defining performance criteria adapted to multi-static scenarios. Several scenarios will be explored, considering one or multiple sources and receivers located at different angular positions, in order to establish relevant performance criteria. Then, the influence of the (single or multiple) periodicity of networks made entirely of lossy polymers and composites will be studied. For experimental validations, the team will rely on its expertise in shaping complex geometries of materials (polymers and composites) using additive technologies previously exploited for the design of original absorbers in transmission lines or free space. The ultimate objective will be the design of a high-performance periodic surface in terms of multi-static scenarios over a wide frequency range (BPR > 100%).

The outcomes of the thesis will contribute to the definition of performance criteria and optimization strategies for addressing new threats in the field of stealth technology. They can be extended to civilian applications through synthesis methods adapted to specific issues (fixed angular positions of source and receiver). Furthermore, findings will allow us to consider broader reflections on the form of measurement chambers and the position of absorbing surfaces in the field of metrology.

 

Dates, location, supervision, and mentoring

§  Start: October 2024

§  Location: Lab-STICC, University of Brest (Université de Bretagne Occidentale), Brest

§  Thesis supervisor: Vincent LAUR

§  Mentoring: Lana DAMAJ et Sophie LASQUELLEC

 

Profile and application

§  Master's degree student or final year of an engineering program

§  Physics, electronics, or telecommunications field

§  Application (CV + motivation letters + transcripts) by email to [email protected]

References

[1] S. Lasquellec, L. Damaj, A. Maalouf, A. Chevalier, V. Laur, « Etude de la réflexion spéculaire et non spéculaire de réseaux de pyramides absorbantes », Journées Nationales Microondes, june 2024, submitted.

[2] Y. Arbaoui, V. Laur, A. Maalouf, P. Queffelec, D. Passerieux, A. Delias, P. Blondy, “Full 3D printed microwave termination: a simple and low-cost solution”, IEEE Trans. Micr. Th. & Tech., vol. 64, no. 1, pp. 271-278, January 2016.

[3] A. Pen, A. Chevalier, A. Maalouf, V. Laur, “X-band compact microwave terminations”, IEEE Asia-Pacific Microwave Conference, Kyoto-Japon, interactive forum, November 2018.

[4] E. Roué, V. Laur, A. Chevalier, G. Tanné, C. Patris, O. Vendier, R.M. Sauvage, “Three-Dimensional Printing of a Waveguide Termination for Millimeter Wave Applications”, 24th IEEE European Microwave Week, Londres, February 2022.

[5] G. Zinkiewicz, A. Chevalier, P. Laurent, J. Benedicto, A. Maalouf, V. Laur, “Toward ultra-compact multi-materials rectangular waveguide terminations”, IEEE Trans. Micr. Th. & Tech., vol. 71, no. 1, pp. 12-21, January 2023.

[6] A. Chevalier, V. Laur, “Composites-based Microwave Absorbers: Toward a Unified Model”, IEEE International Microwave Symposium, Honolulu-USA, session orale, juin 2017.

[7] V. Laur, A. Maalouf, A. Chevalier, F. Comblet, “Study of 3D printed HoneyComb Microwave Absorbers”, IEEE International Symposium on Antennas and Propagation, Atlanta-USA, session orale, July 2019.

[8] V. Laur, A. Maalouf, A. Chevalier, F. Comblet, “Three-Dimensionnal Printing of Honeycomb Microwave Absorbers: Feasibility and Innovative Multiscale Topologies”, IEEE Trans. Electromag. Comp., vol. 63, no. 2, pp. 390-397, April 2021.

[9] C. Vong, A. Chevalier, A. Maalouf, J. Ville, J.F. Rosnarho, V. Laur, “Manufacturing of a magnetic composite flexible filament and optimization of a 3D printed wideband electromagnetic multilayer absorber in X-Ku frequency band”, Materials, vol. 15, no. 9, pp. 3320, May 2022.

[10] C. Vong, A. Chevalier, A. Maalouf, J.F. Rosnarho, J. Ville, V. Laur, “3D-printed multi-materials wideband microwave absorbers”, IEEE Int. Micr. Symp., San Diego, June 2023.

Requirements

Research Field

Physics » Electronics

Education Level

Master Degree or equivalent

Skills/Qualifications

Profile and application

• Master's degree student or final year of an engineering program
• Physics, electronics, or telecommunications field
• Contract PhD scholarship: 36 months

Languages

FRENCH

Languages

ENGLISH

Additional Information
Work Location(s)

Number of offers available

1

Company/Institute

Universite de Brest

Country

France

City

Brest

Geofield

Where to apply

E-mail

[email protected]

Contact

City

Brest Cedex 3

Website

http://www.univ-brest.fr/

Street

6 avenue Le Gorgeu

Postal Code

29238

E-Mail

[email protected]

STATUS: EXPIRED