摘要 :
Two-dimensional (2-D) metallic wire arrays are studied as effective media with an index of refraction less than unity (n eff < 1). The effective medium parameters (permittivity ¿eff, permeability ¿eff and neff) of a wire array are extracted from the finite-element simulated scattering parameters and verified through a 2-D electromagnetic band gap (EBG) structure case study. A simple design methodology for directive monopole antennas is introduced by embedding a monopole within a metallic wire array with (n eff < 1) at the antenna operating frequencies. The narrow beam effect of the monopole antenna is demonstrated in both simulation and experiment at X-band (8-12 GHz). Measured antenna properties including reflection coefficient and radiation patterns are in good agreement with simulation results. Parametric studies of the antenna system are performed. The physical principles and interpretations of the directive monopole antenna embedded in the wire array medium are also discussed....
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Two-dimensional (2-D) metallic wire arrays are studied as effective media with an index of refraction less than unity (n eff < 1). The effective medium parameters (permittivity ¿eff, permeability ¿eff and neff) of a wire array are extracted from the finite-element simulated scattering parameters and verified through a 2-D electromagnetic band gap (EBG) structure case study. A simple design methodology for directive monopole antennas is introduced by embedding a monopole within a metallic wire array with (n eff < 1) at the antenna operating frequencies. The narrow beam effect of the monopole antenna is demonstrated in both simulation and experiment at X-band (8-12 GHz). Measured antenna properties including reflection coefficient and radiation patterns are in good agreement with simulation results. Parametric studies of the antenna system are performed. The physical principles and interpretations of the directive monopole antenna embedded in the wire array medium are also discussed.
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摘要 :
Transparent conducting aluminum-doped zinc oxide (AZO) can be used as part of an active plas-monic device due to its electrically tunable permittivity, which is accomplished by changing the carrier concentration with electrical bi...
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Transparent conducting aluminum-doped zinc oxide (AZO) can be used as part of an active plas-monic device due to its electrically tunable permittivity, which is accomplished by changing the carrier concentration with electrical biasing. In this letter, we report a continuous electrical tuning of diffraction efficiency from AZO gratings in the visible range (specifically 532 nm) when the AZO is under bias voltages between — 1 V and —3.5 V. The carrier concentration in AZO under negative bias has been measured and simulated. The diffraction efficiency changes have been explained by the carrier concentration variation and induced complex refractive index change at the Al_2O_3 and AZO interface. The reported results can lead toward the application of post-fabrication tuning of optoelectronic devices using AZO.
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