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A novel approach for analysis of the scattering response of aperiodic quasicrystalline gratings is proposed. The method exploits the fact that mathematically quasicrystals can be obtained as irrational projections of higher-dimensional periodic structures onto the physical space. The periodicity in the super-space allows for application of plane wave expansion methods such as Rigorous Coupled-Wave...
Optical properties of aperiodic arrays of gold cylinders in the visible range are studied experimentally and analytically. Aperiodic samples based on Ammann-Beenker and Danzer tilings were fabricated and illuminated with visible light. The arrays are composed of gold cylinders with a diameter of 175 nm and a height of 50 nm in a fused silica medium. The images of the arrays showed multiple colors...
Local field enhancements in aperiodic arrays of gold nanospheres are studied. The arrays are based on three aperiodic tilings of the plane which display 5, 7, and 8 fold rotational symmetries that are not possible in conventional periodic arrays. Electromagnetic (EM) field calculations are based on the analytical generalized Mie theory (GMT). It will be shown that despite the fact that aperiodic arrays...
Optical properties of aperiodic aggregates of gold nanospheres are studied. The optical response of these arrays can be explained in terms of the grating response of the array (photonic resonance) and the plasmonic response of the spheres (plasmonic resonance). In particular the couplings between the photonic and plasmonic modes are studied. In periodic arrays this coupling leads to the formation...
A new method for designing broadband transmission gratings with wide field of view for solar cell applications is proposed. The method is based on forming the sidewalls of the gratings according to polynomial functions. To achieve the optimal response, the roots of the polynomial are optimized. This method allows for generating complex sidewall profiles while keeping the number of variables at a manageable...
A new all-dielectric metamaterial design methodology based on effective medium theory is proposed for perfect optical mirrors. The optical metamaterial parameters required to obtain a high reflection are derived. A robust genetic algorithm technique is then employed to evolve the optimal design for an optical mirror targeting near-perfect reflection at 3.3 µm (3.5 µm with substrate loading effects...
In this paper, a new design methodology is suggested to create robust antenna array configurations for application in micro-UAV swarms. The method is based on aperiodic tiling of the plane and, as part of the design process, employs a modified version of the perturbation method first introduced. These modifications add more degrees of freedom to the design process, thereby making the optimization...
We have proposed a single-material all-dielectric optical filter design to provide efficient transmission of light using aSi. An angularly independent low-pass optical filter was presented designed using a GA which optimized for material thickness, sidewall profile and periodicity. A traditional thin-film multilayer filter was designed, which produced comparable results. Further study could be done...
In this paper, we extend the generation of aperiodic antenna arrays into threedimensions. A certain type of the aperiodic tiling of 3-D space is introduced and spherical arrays of a specified radius are generated based on this tiling. The radiation properties of this type of array are studied and compared to a periodic array with the same aperture size. It is shown that, similar to the planar aperiodic...
Design of stacked-patch antennas using magneto-dielectric substrates was investigated. In particular, special types of substrates with identical relative permittivity and permeability were considered. The optimal design parameters were determined using a genetic algorithm. It will be shown that by employing these matched magneto-dielectric substrates, a significant miniaturization of up to 60% can...
In this paper, the use of magneto-dielectric layers will be extended to the application of stacked-patch antenna designs. The low profile and wide bandwidth of microstrip stacked-patch antennas makes them an attractive choice for many RF applications. It will be shown that even with moderate values of xir and mur it is possible to considerably reduce the size (length, width, and thickness) of these...
In this paper we consider the problem of binary hypothesis detection in wireless sensor networks under power constraint. The objective is to solve the resource allocation problem for this distributed detection problem and find a suitable operating point for the network. We consider the Neyman-Pearson (NP) criteria and design suitable transmission schemes and a fusion center (FC) detector, so that...
This paper addresses the problem of lifetime maximization under unequal and time-varying channel conditions, individual battery constraints, and estimation quality requirements at the fusion center. The standard tool for solving this problem (dynamic programming) has exponential complexity with number of sensors and states and needs heavy information exchange with sensors at each iteration. Also errors...
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