We report on the experimental verification of the employment of equivalent parameters in a 2D finite element model to describe absorptivity of curve-shaped, large-scale metamaterial structures. Equivalent homogeneous optical parameters were retrieved from experimental measurements of flat metamaterial sheets with square resonators of 8 and 9 mm and used in a 2D FE model to obtain the absorptivity of curved structures with similar metamaterial unit cells. The curved structures were experimentally characterized and showed good agreement with the model. The tremendous simplification made possible by simulating complex structures as homogeneous materials makes the method very attractive for designing large-scale electromagnetic shields and absorbers.
Microwave metasurfaces have been developing rapidly for various applications, typically fabricated on rigid substrates such as silicon and printed circuit board using conventional microfabrication and related techniques. Rapid prototyping and production is desirable for quick design changes, design flexibility for different applications, manufacturing and low cost. Here, we report on the production of microwave metasurfaces using inkjet-printed Ag conductive patterns on polyester sheets as transparent and flexible substrates. The design is shown to be easily reconfigurable between single-band absorption achieved with a single layer of metal array pattern and multi-band absorption achieved either by stacking various single-band sheets or by printing a complex pattern on a single sheet. The dielectric thickness is varied by the simple addition of blank polyester sheets between the sheet with the printed pattern and the ground plane. Optimal dielectric thickness for each combination of materials and geometries defining the metasurface has been achieved by varying the number of blank sheets to maximize the absorption to near perfect levels in each case. This method is amenable for rapidly producing narrowband and broadband metasurfaces for various applications.
We present a broadly applicable in situ method for profiling ion beams using electrostatic deflectors and a Faraday cup. By deconvolving the detector geometry from the resulting current profiles, spatially resolved absolute current density profiles are obtained. We demonstrate this method’s efficacy with low-density highly charged ion beams (specifically, Ne8+). Details on experimental design are provided as well as the link to the deconvolution routine on GitHub.
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