Tunable negative permittivity in nano-carbon coated magnetic microwire polymer metacomposites

Microwave Properties of Metacomposites Containing Carbon Fibres and Ferromagnetic Microwires

“…To the best of the authors' knowledge, this significant microwave direction dependency is identified for the first time in metacomposites with a parallel wires configuration, and it is reminiscent of a similar feature obtained in orthogonal microwire metacomposites [7]. The orthogonal microwire architecture still requires the presence of a parallel array of microwires in the fibre reinforcing direction due to magnetic interactions among wires that can contribute to the generation of negative permeability and hence of the DNG properties [7]. Obviously, such a presence of those wires is a burden design as additional amount of wires is required.…”

“…This direction-dependent microwave characteristic of the metacomposites containing continuous CFs and microwires can activate or suppress the metamaterial characteristics by rotating the electrical excitation by 90 degrees. To the best of the authors' knowledge, this significant microwave direction dependency is identified for the first time in metacomposites with a parallel wires configuration, and it is reminiscent of a similar feature obtained in orthogonal microwire metacomposites [7]. The orthogonal microwire architecture still requires the presence of a parallel array of microwires in the fibre reinforcing direction due to magnetic interactions among wires that can contribute to the generation of negative permeability and hence of the DNG properties [7].…”

“…However, issues such as narrow DNG bandwidth, poor tunabilities, and high manufacturing costs of metamaterials have limited their industrial exploitation [5]. In this context, as part of a campaign to bring added functionalities to structural composites, we have designed and manufactured “metacomposites” where metamaterial features are integrated with a structural glass-fibre reinforced polymer (GFRP) composite via embedding ferromagnetic microwires [6, 7]. As elucidated in a recent work [6], these metacomposites differ from conventional metamaterials on three basic aspects: (i) they are materials rather than structures, or systems of structures; (ii) they can be produced by using conventional composites manufacturing techniques, instead of micro-/nanofabrication techniques to make complicated building blocks; and (iii) their ultimate properties are dependent not only on the geometric parameters of the architecture, but also on the intrinsic characteristics of the fillers.…”

Negative Permittivity Behavior in Silver/Polyaniline Metacomposites Induced by the Low-Frequency Plasmonic Oscillation

“…In recent years, metacomposites have been widely considered for novel epsilon-negative materials [5].…”

Microwave programmable response of Co-based microwire polymer composites through wire microstructure and arrangement optimization

“…phenomena/microwave absorption) have been shown in composites containing such wires, their electromagnetic response is limited to topological factors and magnetic field/stress stimuli [3][4][5][6][7]. Most recently, inspired by the enhancement in the mechanical and electromagnetic properties of hybrid composites by the addition of nano-carbons [8-11] we adopted the multiscale design philosophy by adding carbon fillers into the microwire composites [12,13]. However, such an approach required delicate control and fine-tuning of the constitutive parameters of the nano-carbons.Considering that the wires' intrinsic electromagnetic parameters relate to their microstructure, we propose to add to these methods a programming-based strategy by incorporating arrays of the same type of microwire but with different internal structure and adjusting their combination within the composite.…”