M. Mohammad Marvasti présente son projet de thèse

Doctorat en sciences et technologies de l’information – 3081

Projet de thèse

Mardi 3 décembre 2024, 10h00 sur ZOOM

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Présentation de : M. Mohammad Marvasti

Titre : THEORETICAL AND NUMERICAL ANALYSES OF ELECTROMAGNETIC PHENOMENA WITH MOVING OBJECTS : APPLICATIONS TO RADARS, ASTROPHYSICS AND ELECTROMAGNETIC GYROSCOPES

Résumé:

The study of electromagnetic problems involving moving objects has numerous applications, including RF Doppler radars, astrophysics, GPS, and electromagnetic gyroscopes. This research presents an original and comprehensive analysis of electromagnetic wave behavior in the presence of moving bodies, utilizing the finite-difference time-domain (FDTD) method. Movement is modeled by updating object positions at specific time steps within the FDTD loop, assuming implicitly absolute time and without applying Voigt-Lorentz transformations. This direct approach is suitable for non-relativistic speeds, addressing typical electromagnetic challenges in areas like antennas and wave propagation.

The study investigates various scenarios: a moving plane wave source, a moving observation point, a moving inclined Partially Reflecting Surface (PRS), a moving line source, a metallic cylinder, etc… illuminated by a plane wave. Results, analyzed in terms of Doppler frequency shifts and electric field amplitude changes.

The findings offer fresh physical insights into wave propagation with moving sources. Specifically, it is demonstrated that the amplitude of the electric field from an ideal plane wave source (low output impedance) is unaffected by the source’s speed. In cases of moving, scattering metallic surfaces, phenomena similar to shock waves appear. Further investigated cases include complex motion scenarios (multi-speed systems, acceleration, vibration, and rotation), as well as applications to moving airplanes, and classic experiments such as the Michelson-Morley interferometer, Sagnac effect, Compton effect, and Heaviside faster-than-light analysis.

To validate the numerical methods, an experimental setup employing Doppler radar was implemented. This setup included a millimeter-wave radar system operating in the 24 GHz ISM band, combined with a moving object (either a metronome or a hand) and a green screen recorded video of the moving target. The recorded motion of these objects was incorporated into FDTD simulations. Comparative analysis of the measured and simulated Doppler signals demonstrated a strong agreement, effectively replicating observed behaviors such as rhythmic oscillations in a metronome and dynamic hand gestures. This experimental validation confirms the accuracy and reliability of the proposed simulation model, highlighting its applicability for practical millimeter-wave radar scenarios and paving the way for further enhancements in radar system design.

Jury d’évaluation :

Président: Prof. Soulaimane Berkane (UQO)

Évaluateur externe : Prof. Mourad Nedil (UQAT)

Évaluateur interne : Prof. Ana-Maria Cretu (UQO)

Directeur de thèse : Prof. Halim Boutayeb

Prof. Halim Boutayeb

Directeur du module d’ingénieirie

Département d'informatique et d’ingénierie

Université du Québec en Outaouais (UQO) 
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