Analysis of dielectric-loaded cavities using an orthonormal-basis method
ABSTRACT An orthonormal-basis method to analyze dielectric-loaded cavities is proposed. Resonant frequencies and fields are obtained by solving an eigenvalue problem in which the modes of an auxiliary problem define the orthonormal-basis that is used to expand the fields of the original problem. The merit of our approach is to take advantage of some mathematical properties to develop a computationally efficient and versatile method. The accuracy of the method is demonstrated by comparing our results with other results available in the literature.
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ABSTRACT: The effect of the slope of the groove walls in the behavior of thin-film one-dimensional photonic crystal waveguides is extensively studied. In this respect, we point out its influence on the modal dispersion relations and then on the bandgap structure in general. Likewise, we also prove the lack of accuracy in the evaluation of the bandgap edges when material dispersion is ignored. The extreme importance of both facts, the wall slope and the material dispersion, in the analysis and design of realistic photonic crystal devices is emphasized. In particular, we exploit the wall slope as a new design parameter. By suitably choosing the value of the above parameter, sloped-wall photonic crystal waveguides with high quality factor or high group velocity dispersion can be achieved.IEEE Photonics Technology Letters 03/2005; · 2.19 Impact Factor
Article: Traceable 2D finite-element simulation of the whispering-gallery modes of axisymmetric electromagnetic resonators[show abstract] [hide abstract]
ABSTRACT: This paper explains how a popular, commercially-available software package for solving partial-differential-equations (PDEs), as based on the finite-element method (FEM), can be configured to calculate, efficiently, the frequencies and fields of the whispering-gallery (WG) modes of axisymmetric dielectric resonators. The approach is traceable; it exploits the PDE-solver's ability to accept the definition of solutions to Maxwell's equations in so-called `weak form'. Associated expressions and methods for estimating a WG mode's volume, filling factor(s) and, in the case of closed(open) resonators, its wall(radiation) loss, are provided. As no transverse approximation is imposed, the approach remains accurate even for quasi-transverse magnetic/electric modes of low, finite azimuthal mode order. The approach's generality and utility are demonstrated by modeling several non-trivial structures: (i) two different optical microcavities [one toroidal made of silica, the other an AlGaAs microdisk]; (ii) a 3rd-order sapphire:air Bragg cavity; (iii) two different cryogenic sapphire WG-mode resonators; both (ii) and (iii) operate in the microwave X-band. By fitting one of (iii) to a set of measured resonance frequencies, the dielectric constants of sapphire at liquid-helium temperature have been estimated.12/2006;
Article: Miniaturized high impedance surfaces with angular stability by using zirconium tin titanate substrates and convoluted FSS elements[show abstract] [hide abstract]
ABSTRACT: A new approach for obtaining metasurfaces realized by using frequency selective surfaces with reduced periodicity printed on a new class of high dielectric constant materials is presented. The proposed engineered ad-hoc materials and the innovative electromagnetic design provide an improvement of the overall device in terms of compactness and angular stability, as shown by the use of our novel band vs. incidence angles chart. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2753–2758, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24731Microwave and Optical Technology Letters 08/2009; 51(11):2753 - 2758. · 0.62 Impact Factor