1,721,046 research outputs found
A BEM formulation for efficient and accurate analysis of dielectric waveguiding structures: Extension to multiboundary topologies
No full textA recently proposed formulation based on the boundary element method (BEM) has been demonstrated to be very accurate and efficient for the modal analysis of arbitrarily shaped dielectric waveguides. This innovative approach is extended here to analyze any topology having multiple contours and/or dielectrics, thus permitting a complete characterization for guiding structures that are frequently utilized in several applications at microwaves, millimeter waves, and optics. Various tests validate the excellent computational properties of this method even for compound structures. © 1998 John Wiley & Sons, Inc
Full-wave modal analysis of arbitrarily-shaped dielectric waveguides through an efficient boundary-element-method formulation
No full textAnalisi di strutture dielettriche mediante il metodo degli elementi al contorno
No full textpremio Giorgio Barzilai per il miglior lavoro di giovani autor
Full-wave analysis of bound and leaky modes propagating along 2D periodic printed structures with arbitrary metallisation in the unit cell
No full textA full-wave numerical approach for the analysis and design of two-dimensional printed periodic structures on a grounded dielectric slab is presented. Electromagnetic band-gap surfaces, metamaterials and leaky-wave antennas are important special cases of structures that can be analysed. The proposed technique permits the analysis of an arbitrary metallisation within the unit cell; it is based on a mixed-potential integral equation solved by the method of moments in the spatial domain. Two-dimensional periodic vector and scalar Green’s functions are derived in the spectral domain and an appropriate choice of the spectral determination for each spatial harmonic is performed to properly account for leakage effects. The proposed approach is used to calculate the real propagation wavenumber for surface waves in their pass-band regimes, propagating at arbitrary angles on two-dimensional periodic printed structures. Complex propagation wavenumbers can be derived as well for both bound modes in their stop-band regimes and proper and improper leaky modes in their relevant physical and non-physical regions. Results for a reference uniplanar compact photonic bandgap structure are reported demonstrating how the application of this rigorous technique provides a new detailed picture of the different modal behaviours and a more accurate determination of its band-gap zones
Analysis of arbitrary waveguides by means of a generalized Boundary-Element-Method approach
No full textRigorous evaluation of ohmic-loss effects for accurate design of traveling-wave antennas
No full textIn this work, the effects of the ohmic losses on the radiation properties are extensively evaluated for the general class of the traveling-wave antennas. For arbitrary aperture distributions, rigorous analytical approaches have been developed to take into account the dissipation in conductors and/or dielectrics that can adversely affect the basic design parameters, such as efficiency and leakage constant. Consequently, fundamental information is achieved both to quantify the alterations in the antenna performances due to misappreciation of the ohmic losses and, above all, to appropriately correct the synthesis procedures for improved radiation patterns. Important applications of this analysis refer to topologies of leaky-wave antennas
Radiation and leakage phenomena in waveguides with gyrotropic substrates
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