摘要 :
Near-field analytical expressions for the plane-wave scattering from an electrically small circular aperture on an infinite conducting screen were derived based on the Bethe-Bouwkamp (BB) quasi-static model. The formulation of the...
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Near-field analytical expressions for the plane-wave scattering from an electrically small circular aperture on an infinite conducting screen were derived based on the Bethe-Bouwkamp (BB) quasi-static model. The formulation of the problem implements the equivalence principle and image theory in order to express the scattered fields in the near zone in terms of the vector potential F?. The vector potential is defined as a surface integral of the first-order BB approximation of the magnetic current on the aperture multiplied by the governing free-space Green's function. The free-space Green's function was expanded using Taylor series, thus producing integrals that can be evaluated analytically for the case where the observation point resides on the axis of the aperture. Results for the scattered electric field along the axis of the aperture, using the obtained closed-form near-field expressions, were validated against recently published results in the literature.
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摘要 :
Near-field analytical expressions for the plane-wave scattering from an electrically small circular aperture on an infinite conducting screen were derived based on the Bethe-Bouwkamp (BB) quasi-static model. The formulation of the...
展开
Near-field analytical expressions for the plane-wave scattering from an electrically small circular aperture on an infinite conducting screen were derived based on the Bethe-Bouwkamp (BB) quasi-static model. The formulation of the problem implements the equivalence principle and image theory in order to express the scattered fields in the near zone in terms of the vector potential F⃗. The vector potential is defined as a surface integral of the first-order BB approximation of the magnetic current on the aperture multiplied by the governing free-space Green's function. The free-space Green's function was expanded using Taylor series, thus producing integrals that can be evaluated analytically for the case where the observation point resides on the axis of the aperture. Results for the scattered electric field along the axis of the aperture, using the obtained closed-form near-field expressions, were validated against recently published results in the literature.
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摘要 :
Near-field analytical expressions for the plane-wave scattering from an electrically small circular aperture on an infinite conducting screen were derived based on the Bethe-Bouwkamp (BB) quasi-static model. The formulation of the...
展开
Near-field analytical expressions for the plane-wave scattering from an electrically small circular aperture on an infinite conducting screen were derived based on the Bethe-Bouwkamp (BB) quasi-static model. The formulation of the problem implements the equivalence principle and image theory in order to express the scattered fields in the near zone in terms of the vector potential F. The vector potential is defined as a surface integral of the first-order BB approximation of the magnetic current on the aperture multiplied by the governing free-space Green's function. The free-space Green's function was expanded using Taylor series, thus producing integrals that can be evaluated analytically for the case where the observation point resides on the axis of the aperture. Results for the scattered electric field along the axis of the aperture, using the obtained closed-form near-field expressions, were validated against recently published results in the literature.
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摘要 :
A subdomains splicing technique for iterative physical optics (IPO) approach has been presented. It can be applied widely to calculate the radar cross section (RCS) of electrically large size cavities, and to greatly reduce the nu...
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A subdomains splicing technique for iterative physical optics (IPO) approach has been presented. It can be applied widely to calculate the radar cross section (RCS) of electrically large size cavities, and to greatly reduce the numerical computation time. The new approach is to split a cavity into some subcavities and to analyze each subcavity with the IPO approach. The electromagnetic coupling of each subcavity has been considered by a loop iterative in the whole cavity. Some numerical results have been shown to verify present approach.
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The classical electromagnetic (EM) and acoustic waves interact with metamaterials in interestingly resembling manner. A robust technique is described to retrieve effective medium parameters for both acoustic and electromagnetic fi...
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The classical electromagnetic (EM) and acoustic waves interact with metamaterials in interestingly resembling manner. A robust technique is described to retrieve effective medium parameters for both acoustic and electromagnetic fields using scattering parameters as input. To establish the applicability of technique a Fano resonator metamaterial is designed that supports response in EM and acoustics regime. The acoustic wave interaction with metamaterial exhibit exclusive negative band of effective bulk density (P
eff
). On the other hand, electromagnetic wave interaction with metamaterial gives negative band of effective permittivity (
$\epsilon_{\text{eff}}$
). The proposed method to extract effective medium parameters for classical waves interacting with metamaterials offers potential for design and characterisation of micro/nano electromechanical systems MEMs/NEMs.
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摘要 :
The classical electromagnetic (EM) and acoustic waves interact with metamaterials in interestingly resembling manner. A robust technique is described to retrieve effective medium parameters for both acoustic and electromagnetic fi...
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The classical electromagnetic (EM) and acoustic waves interact with metamaterials in interestingly resembling manner. A robust technique is described to retrieve effective medium parameters for both acoustic and electromagnetic fields using scattering parameters as input. To establish the applicability of technique a Fano resonator metamaterial is designed that supports response in EM and acoustics regime. The acoustic wave interaction with metamaterial exhibit exclusive negative band of effective bulk density (P
eff
). On the other hand, electromagnetic wave interaction with metamaterial gives negative band of effective permittivity (
$\epsilon_{\text{eff}}$
). The proposed method to extract effective medium parameters for classical waves interacting with metamaterials offers potential for design and characterisation of micro/nano electromechanical systems MEMs/NEMs.
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摘要 :
The possibility of numerical solving diffraction problems of electromagnetic wave by bodies with non-coordinate boundaries by reducing to infinite sets of linear algebraic equations is investigated. The coefficients of expansion o...
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The possibility of numerical solving diffraction problems of electromagnetic wave by bodies with non-coordinate boundaries by reducing to infinite sets of linear algebraic equations is investigated. The coefficients of expansion of the unknown field in terms of eigen waves of coordinate domains are unknown objects. Expansions of the unknown field in terms of cylindrical and spherical waves are used for solving the problem of diffraction of an electromagnetic wave by a cylindrical rod with a non-coordinate boundary and the problem of diffraction of two-dimensional wave by the axis-symmetrical body.
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Scattering characteristic modes (CMs) are a set of independent and complete fundamental working modes of the objective scatterer. The CMs satisfy a series of valuable features, such as the energy decoupling feature expressed as fi...
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Scattering characteristic modes (CMs) are a set of independent and complete fundamental working modes of the objective scatterer. The CMs satisfy a series of valuable features, such as the energy decoupling feature expressed as field-current interaction and the field-field orthogonality feature expressed as field-field interaction. The features have become the theoretical foundation of the CM-based engineering applications. In this paper, both the energy decoupling and field-field orthogonality features are simply reviewed first, and then the field-field orthogonality feature is further generalized.
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This paper presents a study of the sensibility of the incoherent (electromagnetic backscattering model) and coherent (DInSAR and PolInSAR inversion) crop height estimation methods of SAR imaging. The methods were compared for padd...
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This paper presents a study of the sensibility of the incoherent (electromagnetic backscattering model) and coherent (DInSAR and PolInSAR inversion) crop height estimation methods of SAR imaging. The methods were compared for paddy-rice crop height monitoring with a TanDEM-X dataset. For this, rice-cultivated agricultural fields located in Northern Turkey were selected. Intensive ground data collection during the cultivation period in 2015 was carried out. The accuracy analysis showed that the requirement of external (vegetation-free) DEM in DInSAR-based crop height estimation decreases its performance compared to the PolInSAR and backscattering inversion methods.
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摘要 :
This paper presents a study of the sensibility of the incoherent (electromagnetic backscattering model) and coherent (DInSAR and PolInSAR inversion) crop height estimation methods of SAR imaging. The methods were compared for padd...
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This paper presents a study of the sensibility of the incoherent (electromagnetic backscattering model) and coherent (DInSAR and PolInSAR inversion) crop height estimation methods of SAR imaging. The methods were compared for paddy-rice crop height monitoring with a TanDEM-X dataset. For this, rice-cultivated agricultural fields located in Northern Turkey were selected. Intensive ground data collection during the cultivation period in 2015 was carried out. The accuracy analysis showed that the requirement of external (vegetation-free) DEM in DInSAR-based crop height estimation decreases its performance compared to the PolInSAR and backscattering inversion methods.
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