Three-dimensional metallic fractals and their photonic crystal characteristics

Abstract

We report photonic properties of subwavelength three-dimensional ͑3D͒ metallic H-shaped fractals. The fractal structure supports localized resonances with relevant wavelength over ten times the sample size. Owing to the anisotropy inherent to the fractal geometry, the resonances and their induced band gaps are polarization dependent. The measured microwave transmission spectra agree well with simulations, and show the anisotropic response to be well described by an effective dielectric tensor. Using the three-dimensional H fractal as the basic unit, a microwave photonic crystal was fabricated, and its band-gap characteristics shown to display unique features of hybridization between local resonances and Bragg scattering. A photonic crystal of 3D fractals is an excellent microwave analog to an anisotropic electronic solid consisting of atoms or molecules with localized discrete energy levels.

Electromagnetic characteristics of Hilbert curve-based metamaterials

“…The subwavelength property of the fractal patterns is attributed to their peculiar geometrical structure which is featured by self-similarity or scaling invariance, and enables them as excellent building blocks for metamaterials and photonic applications. Recently, the fractal-based metamaterials and photonic structures have been investigated because of their appealing subwavelength and multiband characteristics and been shown to possess more features in dual-band or multi-band gaps than conventional photonic crystals [17][18][19][20][21].…”

A generalized equivalent circuit theory for the electric and magnetic resonances of metallic wire networks

“…Metallic wire structures such as fractals have been shown to be efficient wide band filters. 5,6 New ways of near field subwavelength imaging with negative refraction index material ͑NIM͒ was designed and experimentally verified. [7][8][9][10][11][12] The original NIM consists of metallic split-ring resonators and straight metallic wires; the purpose is to adjust the electric dipole eigenmode in the wire and the "magnetic" eigenmode in the split ring so that their out of phase responses have an overlapping frequency region.…”

“…5,6 The T structure is probably the simplest wire network with a joint and demonstrates the essential features of the eigenmodes. For H-shape wire networks, a rich variety of current configurations are available which exhibit comparable electric or magnetic responses.…”

A Pole and Amc Point Matching Method for the Synthesis of HSF-Uc-Ebg Structure With Simultaneous Amc and Ebg Properties

“…We use the two-dimensional H-shaped fractal unit cell of photonic crystal [22] to construct an anisotropic HSF-UC-EBG structure since anisotropic EBG structures possess rather general dispersion properties to furbish a complete illustrative example. It consists of a patch with period array of H-shaped fractal slots printed on a metal backed substrate (Figure 1(a)).…”