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Wei E. I. Sha - One of the best experts on this subject based on the ideXlab platform.

  • artificial perfect Electric Conductor perfect magnetic Conductor anisotropic metasurface for generating orbital angular momentum of microwave with nearly perfect conversion efficiency
    arXiv: Optics, 2016
    Co-Authors: Menglin L. N. Chen, Li Jun Jiang, Wei E. I. Sha
    Abstract:

    Orbital angular momentum (OAM) is a promising degree of freedom for fundamental studies in electromagnetics and quantum mechanics. The unlimited state space of OAM shows a great potential to enhance channel capacities of classical and quantum communications. By exploring the Pancharatnam-Berry phase concept and engineering anisotropic scatterers in a metasurface with spatially varying orientations, a plane wave with zero OAM can be converted to a vortex beam carrying nonzero OAM. In this paper, we proposed two types of novel PEC (perfect Electric Conductor)-PMC (perfect magnetic Conductor) anisotropic metasurfaces. One is composed of azimuthally continuous loops and the other is constructed by azimuthally discontinuous dipole scatterers. Both types of metasurfaces are mounted on a mushroom-type high impedance surface. Compared to previous metasurface designs for generating OAM, the proposed ones achieve nearly perfect conversion efficiency. In view of the eliminated vertical component of Electric field, the continuous metasurface shows very smooth phase pattern at the near-field region, which cannot be achieved by convectional metasurfaces composed of discrete scatterers. On the other hand, the metasurface with discrete dipole scatterers shows a great flexibility to generate OAM with arbitrary topological charges. Our work is fundamentally and practically important to high-performance OAM generation.

  • Artificial Perfect Electric Conductor-Perfect Magnetic Conductor Anisotropic Metasurface for Generating Orbital Angular Momentum of Microwave with Nearly Perfect Conversion Efficiency
    Journal of Applied Physics, 2016
    Co-Authors: Menglin L. N. Chen, Li Jun Jiang, Wei E. I. Sha
    Abstract:

    Orbital angular momentum (OAM) is a promising degree of freedom for fundamental studies in electromagnetics and quantum mechanics. The unlimited state space of OAM shows a great potential to enhance channel capacities of classical and quantum communications. By exploring the Pancharatnam-Berry phase concept and engineering anisotropic scatterers in a metasurface with spatially varying orientations, a plane wave with zero OAM can be converted to a vortex beam carrying nonzero OAM. In this paper, we proposed two types of novel perfect Electric Conductor-perfect magnetic Conductor anisotropic metasurfaces. One is composed of azimuthally continuous loops and the other is constructed by azimuthally discontinuous dipole scatterers. Both types of metasurfaces are mounted on a mushroom-type high impedance surface. Compared to previous metasurface designs for generating OAM, the proposed ones achieve nearly perfect conversion efficiency. In view of the eliminated vertical component of Electric field, the continuou...

Menglin L. N. Chen - One of the best experts on this subject based on the ideXlab platform.

  • artificial perfect Electric Conductor perfect magnetic Conductor anisotropic metasurface for generating orbital angular momentum of microwave with nearly perfect conversion efficiency
    arXiv: Optics, 2016
    Co-Authors: Menglin L. N. Chen, Li Jun Jiang, Wei E. I. Sha
    Abstract:

    Orbital angular momentum (OAM) is a promising degree of freedom for fundamental studies in electromagnetics and quantum mechanics. The unlimited state space of OAM shows a great potential to enhance channel capacities of classical and quantum communications. By exploring the Pancharatnam-Berry phase concept and engineering anisotropic scatterers in a metasurface with spatially varying orientations, a plane wave with zero OAM can be converted to a vortex beam carrying nonzero OAM. In this paper, we proposed two types of novel PEC (perfect Electric Conductor)-PMC (perfect magnetic Conductor) anisotropic metasurfaces. One is composed of azimuthally continuous loops and the other is constructed by azimuthally discontinuous dipole scatterers. Both types of metasurfaces are mounted on a mushroom-type high impedance surface. Compared to previous metasurface designs for generating OAM, the proposed ones achieve nearly perfect conversion efficiency. In view of the eliminated vertical component of Electric field, the continuous metasurface shows very smooth phase pattern at the near-field region, which cannot be achieved by convectional metasurfaces composed of discrete scatterers. On the other hand, the metasurface with discrete dipole scatterers shows a great flexibility to generate OAM with arbitrary topological charges. Our work is fundamentally and practically important to high-performance OAM generation.

  • Artificial Perfect Electric Conductor-Perfect Magnetic Conductor Anisotropic Metasurface for Generating Orbital Angular Momentum of Microwave with Nearly Perfect Conversion Efficiency
    Journal of Applied Physics, 2016
    Co-Authors: Menglin L. N. Chen, Li Jun Jiang, Wei E. I. Sha
    Abstract:

    Orbital angular momentum (OAM) is a promising degree of freedom for fundamental studies in electromagnetics and quantum mechanics. The unlimited state space of OAM shows a great potential to enhance channel capacities of classical and quantum communications. By exploring the Pancharatnam-Berry phase concept and engineering anisotropic scatterers in a metasurface with spatially varying orientations, a plane wave with zero OAM can be converted to a vortex beam carrying nonzero OAM. In this paper, we proposed two types of novel perfect Electric Conductor-perfect magnetic Conductor anisotropic metasurfaces. One is composed of azimuthally continuous loops and the other is constructed by azimuthally discontinuous dipole scatterers. Both types of metasurfaces are mounted on a mushroom-type high impedance surface. Compared to previous metasurface designs for generating OAM, the proposed ones achieve nearly perfect conversion efficiency. In view of the eliminated vertical component of Electric field, the continuou...

Ari Sihvola - One of the best experts on this subject based on the ideXlab platform.

  • surface integral equation based characteristic mode formulation for penetrable bodies
    IEEE Transactions on Antennas and Propagation, 2018
    Co-Authors: Pasi Ylaoijala, Henrik Wallen, Dimitrios C Tzarouchis, Ari Sihvola
    Abstract:

    A novel surface integral equation (SIE)-based theory of characteristic modes (TCM) formulation is proposed for homogeneous penetrable bodies. Analytical expressions for the characteristic eigenvalues are presented and good agreement between the numerical and analytical results is observed for both lossless and lossy, as well as for diElectric and magnetodiElectric objects. The new formulations, without any postprocessing methods, avoid spurious modes and resonances appearing in existing SIE-based TCM formulations. For lossy objects, the obtained eigenvalues are complex. The real part of an eigenvalue is related to the ratio of the reactive and radiated power, as in the original TCM formulation for perfect Electric Conductor structures, and the imaginary part gives the ratio between the dissipated and radiated power.

  • transformation method for problems involving perfect electromagnetic Conductor pemc structures
    IEEE Transactions on Antennas and Propagation, 2005
    Co-Authors: I V Lindell, Ari Sihvola
    Abstract:

    Perfect Electric Conductor (PEC) and perfect magnetic Conductor (PMC) can be generalized to perfect electromagnetic Conductor (PEMC), a medium where certain linear combinations of electromagnetic fields are required to vanish. In differential-form representation, the corresponding medium is characterized as the simplest possible medium. It is defined through a scalar admittance parameter, whose zero and infinite limits yield the PMC and PEC media, respectively. In this paper a duality transformation is found that has the property of transforming PEMC to PEC and an isotropic medium to itself. Thus, problems involving PEMC objects in air can be transformed to problems with PEC objects in air which can be solved through traditional techniques and then transformed back. Several simple examples are treated to demonstrate the principle. PEMC has the potential of having similar applications as PMC in antenna engineering and finding structures for its realization is a challenge.

  • perfect electromagnetic Conductor
    Journal of Electromagnetic Waves and Applications, 2005
    Co-Authors: I V Lindell, Ari Sihvola
    Abstract:

    In differential-form representation, the Maxwell equations are represented by simple differential relations between the electromagnetic two-forms and source three-forms while the electromagnetic medium is defined through a constitutive relation between the two-forms. The simplest of such relations expresses the electromagnetic two-forms as scalar multiples of one another. Because of its strange properties, the corresponding medium has been considered as nonphysical. In this study such a medium is interpreted in terms of the classical Gibbsian vectors as a bi-isotropic medium with infinite values for its four medium parameters. It is shown that the medium is a generalization of both PEC (perfect Electric Conductor) and PMC (perfect magnetic Conductor) media, with similar properties. This is why the medium is labeled as PEMC (perfect electromagnetic Conductor). Defining a certain class of duality transformations, PEMC medium can be transformed to PEC or PMC media. As an application, plane-wave reflection fr...

Li Jun Jiang - One of the best experts on this subject based on the ideXlab platform.

  • artificial perfect Electric Conductor perfect magnetic Conductor anisotropic metasurface for generating orbital angular momentum of microwave with nearly perfect conversion efficiency
    arXiv: Optics, 2016
    Co-Authors: Menglin L. N. Chen, Li Jun Jiang, Wei E. I. Sha
    Abstract:

    Orbital angular momentum (OAM) is a promising degree of freedom for fundamental studies in electromagnetics and quantum mechanics. The unlimited state space of OAM shows a great potential to enhance channel capacities of classical and quantum communications. By exploring the Pancharatnam-Berry phase concept and engineering anisotropic scatterers in a metasurface with spatially varying orientations, a plane wave with zero OAM can be converted to a vortex beam carrying nonzero OAM. In this paper, we proposed two types of novel PEC (perfect Electric Conductor)-PMC (perfect magnetic Conductor) anisotropic metasurfaces. One is composed of azimuthally continuous loops and the other is constructed by azimuthally discontinuous dipole scatterers. Both types of metasurfaces are mounted on a mushroom-type high impedance surface. Compared to previous metasurface designs for generating OAM, the proposed ones achieve nearly perfect conversion efficiency. In view of the eliminated vertical component of Electric field, the continuous metasurface shows very smooth phase pattern at the near-field region, which cannot be achieved by convectional metasurfaces composed of discrete scatterers. On the other hand, the metasurface with discrete dipole scatterers shows a great flexibility to generate OAM with arbitrary topological charges. Our work is fundamentally and practically important to high-performance OAM generation.

  • Artificial Perfect Electric Conductor-Perfect Magnetic Conductor Anisotropic Metasurface for Generating Orbital Angular Momentum of Microwave with Nearly Perfect Conversion Efficiency
    Journal of Applied Physics, 2016
    Co-Authors: Menglin L. N. Chen, Li Jun Jiang, Wei E. I. Sha
    Abstract:

    Orbital angular momentum (OAM) is a promising degree of freedom for fundamental studies in electromagnetics and quantum mechanics. The unlimited state space of OAM shows a great potential to enhance channel capacities of classical and quantum communications. By exploring the Pancharatnam-Berry phase concept and engineering anisotropic scatterers in a metasurface with spatially varying orientations, a plane wave with zero OAM can be converted to a vortex beam carrying nonzero OAM. In this paper, we proposed two types of novel perfect Electric Conductor-perfect magnetic Conductor anisotropic metasurfaces. One is composed of azimuthally continuous loops and the other is constructed by azimuthally discontinuous dipole scatterers. Both types of metasurfaces are mounted on a mushroom-type high impedance surface. Compared to previous metasurface designs for generating OAM, the proposed ones achieve nearly perfect conversion efficiency. In view of the eliminated vertical component of Electric field, the continuou...

Jinpeng Fang - One of the best experts on this subject based on the ideXlab platform.

  • application of loop flower basis functions in the time domain Electric field integral equation
    IEEE Transactions on Antennas and Propagation, 2015
    Co-Authors: Xuezhe Tian, Gaobiao Xiao, Jinpeng Fang
    Abstract:

    The loop-flower basis functions are applied to get a low-frequency stable time-domain Electric field integral equation (TD-EFIE). The quasi-Helmholtz decomposition is performed by the loop-flower basis functions, which are all defined based on mesh nodes. To get a well-posed equation, a temporally differentiated form of the TD-EFIE is tested with the flower function and the undifferentiated form is tested with the loop function. For a robust MOT solver, the averaging scheme is also adopted to alleviate the high-frequency instabilities. Numerical verifications of perfect Electric Conductor (PEC) transient scattering problems are provided to demonstrate the accuracy and stability of the proposed technique.