Spatial mapping of the internal and external electromagnetic fields of negative index metamaterials

Department of Electrical and Computer Engineering (ECE), Duke University, Durham, North Carolina, United States
Optics Express (Impact Factor: 3.49). 10/2006; 14(19):8694-705. DOI: 10.1364/OE.14.008694
Source: PubMed


We perform an experimental study of the phase and amplitude of microwaves interacting with and scattered by two-dimensional negative index metamaterials. The measurements are performed in a parallel plate waveguide apparatus at X-band frequencies (8-12 GHz), thus constraining the electromagnetic fields to two dimensions. A detection antenna is fixed to one of the plates, while a second plate with a fixed source antenna or waveguide is translated relative to the first plate. The detection antenna is inserted into, but not protruding below, the stationary plate so that fields internal to the metamaterial samples can be mapped. From the measured mappings of the electric field, the interplay between the microstructure of the metamaterial lattice and the macroscopic averaged response is revealed. For example, the mapped phase fronts within a metamaterial having a negative refractive index are consistent with a macroscopic phase-in accordance with the effective medium predictions-which travels in a direction opposite to the direction of propagation. The field maps are in excellent agreement with finite element numerical simulations performed assuming homogeneous metamaterial structures.

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Available from: Aloyse Degiron, Jun 05, 2015
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    • "However, during the spatial mapping, a ∼1 mm gap between the top surface of the metamaterials and the upper plate has to be maintained in order to facilitate the relative movement between them. So, the metamaterial devices as well as the auxiliary boundary materials under test must be finitely high, for example, 10 mm at X-band frequencies (8–12 GHz) [25] [32] [33]. Consequently, the electric wall or perfect electric conductor (PEC) boundary in the 2D simulations cannot be mimicked, in exact sense, by erecting a finitely high metal wall inside the quasi-2D mapper. "
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    ABSTRACT: Spatially mapping electromagnetic fields in the quasi-two-dimensional field mapper (a parallel plate waveguiding system; Justice et al. (2006)) for characterizing metamaterial devices, especially those integrating the metal boundary, may encounter troubles including electromagnetic leakage caused by the air gap and energy guiding along finitely high metal walls. To eradicate them, a moving contact approach is proposed. The physical air gap between the mobile metal walls and the stationary upper plate of the mapper is closed, while their relative movement is still allowed during the field mapping. We demonstrate the method of closing the gap by mapping the E-field distribution in a rectangular waveguide.
    International Journal of Antennas and Propagation 01/2014; 2014:1-5. DOI:10.1155/2014/728756 · 0.66 Impact Factor
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    • "Figure 1 shows the optimized relative permittivity distribution for the flattened lens, the hole distribution computed by the particle interaction approach described above, and the final fabricated lens. Plots of the simulated and measured electric field distributions are shown in Figure 2. The field distribution was measured using a 2D electric field mapping apparatus previously reported [18]. For both the simulations and the experimental measurements, a source was placed at the focal plane of the lens, with a roughly collimated beam expected as the output. "
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    Sensors 12/2011; 11(8):7982-91. DOI:10.3390/s110807982 · 2.25 Impact Factor
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    • "To investigate the interactions between the fabricated black hole and incident TE-polarized electromagnetic waves, a parallel-plate waveguide near-field scanning system is used to map the field distributions near the black hole at 18 GHz. A similar apparatus has been discussed in Ref. [23]. The separation between two plates is set as 6.5 mm, which is larger than the height of black hole to avoid the unnecessary dragging during measurements. "
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