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Modélisation hyperfréquence de problèmes multi-échelles appliquée au cas des antennes à métamatériaux diélectriques

Abstract : This work focuses on the improvement of the antennas compactness used primarily for embedded systems while respecting the performance and competitiveness requirements. The approach explored consists in using artificial materials operating in transmission and designed by structuring the dielectric material on a scale smaller than the wavelength (sub-wavelength). This structuring makes it possible in practice to achieve a variation in the effective refractive index in order to produce diffractive elements capable of performing a microwave function. However, the particularity of this type of structured element is to mix several physical scales generating complexity in their study. The largest dimension of a structured component can reach several tens of wavelength, for example 20λ, while the minimum size of the sub-wavelength structures may be less than a fraction of the wavelength, as than λ / 20. This multi-scale aspect increases the simulation times of antenna devices integrating these structured elements, thus preventing any possibility of multi-parameter optimization in reasonable times. In order to exploit fully the potential of these structured materials, a numerical model of computation has been developed on the basis of optical paths. This model gives results on the maximum gain of structured diffractive lens antennas with an accuracy of 0.5 dB. The computation time of the model is of the order of the minute compared to more than 6 hours for a complete simulation with the electromagnetic calculation software CST Microwave Studio. The speed and precision of this model have been used to optimize the design of a structured diffractive lens. To illustrate the relevance of this structured approach, its performances were compared with those of Fresnel lens antenna and hyperbolic lens antenna. This comparison was carried out under identical footprint conditions with a length to diameter ratio L / D of 0.5. The gain of the structured lens was found to be 1.6 dB higher than the Fresnel lens and 2.7 dB higher than the hyperbolic lens.
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Submitted on : Friday, November 2, 2018 - 1:04:12 AM
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  • HAL Id : tel-01910809, version 1

Citation

Alpha Ousmane Diallo. Modélisation hyperfréquence de problèmes multi-échelles appliquée au cas des antennes à métamatériaux diélectriques. Génie mécanique [physics.class-ph]. Université Pierre et Marie Curie - Paris VI, 2017. Français. ⟨NNT : 2017PA066356⟩. ⟨tel-01910809⟩

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