3D-Printing for Transformation Optics in Electromagnetic High-Frequency Lens Applications

Abstract

This article presents the design, construction and analysis of a 3D-printed transformed hyperbolic flat lens working on the 30 GHz band. The transformed lens was printed using only one ABS dielectric filament of relative permittivity of 12, varying the infill percentage of each transformed lens section in order to achieve the permittivity values obtained with the transformation optics. The 3D-printed hyperbolic transformed lens exhibits good radiation performance compared to the original canonical lens.

Flexible 3D Printed Conductive Metamaterial Units for Electromagnetic Applications in Microwaves

“…For the purposes of the current study, we used a commercially available Makerbot Replicator 2x; a FDM printer; and two different, commercially available filaments as printing materials, i.e., the polylactic acid (PLA) and the Electrifi. Notably, 3D printing has been already used in fabrication of dielectric microwave metamaterials and components [ 35 , 36 , 37 , 38 , 39 ], and the conductive filaments have been also recently examined [ 40 , 41 ]. However, to the best of our knowledge, this is the first time that such a combination has been used for SRRs.…”

Parametric Study of a Fully 3D-Printed Dielectric Resonator Antenna Loaded With a Metallic Cap

“…Then, by varying the infill percentage of the unit-cell, we retrieve the different dispersion diagrams, and therefore, the relative permittivity for each infill percentage variation. This unit-cell has proved to represent the infill percentage accurately and the relative permittivity obtained with the 3D-printing process [16], [17]. Figure 5 shows the unit-cell and the relative permittivity values as a function of the infill percentage obtained with this analysis for the filament PREPERM ABS1000 (ε r = 10).…”

“…One of the main drawbacks of this technology is the limitation of available permittivity values on standard dielectric materials and that the complexity of the shape either increases the manufacturing cost or is limited by current manufacturing processes. This shape issue can be easily overcome by using 3D-printing, which allows the manufacture of different shapes, only depending on the precision of the printer, while for the permittivity values, we can obtain different dielectric constants just by varying the infill percentage of the 3D-printed dielectric [16], [17], [23].…”

“…Amongst the characteristics that can be controlled in the 3D-printing process of a DRA is the infill percentage of the material, which can affect either from an electromagnetic point of view or directly influence the overall weight of the structure [6], [29], [30]. In the specific case of 3D-printed dielectrics, reducing the infill percentage will reduce the relative permittivity of the structure [16], [17], shifting the resonance frequency of the antenna. To compensate for this effect, and as described in the previous paragraph, we can add a metallic cap and set the resonant frequency on any desired value [27].…”

Gradient-Index-Based Frequency-Coded Retroreflective Lenses for mm-Wave Indoor Localization

“…The most feasible way of construction and design is therefore as stacked perforated dielectric substrates similarly as in [31]. Another construction options are generally based on an additive manufacturing, where the building unit-cells can be of various shapes as cubes (Polymer Jetting -PJ) [32], cuboid grid (Fused Decomposition Modeling -FDM) [33] or 3D crosses (Stereolithography -SLA) [34]. However, it is hard to realize such structures at mm-waves above 80 GHz because of the xy resolution limit of the conventional 3D printers for reliable printing (FDM ≈ 0.4 mm depending on the print nozzle diameter [35], SLA ≈ 0.15 mm depending on the laser spot size [36]), and the requirement for supporting structures, which are too difficult to remove.…”