ChemInform Abstract: Ferromagnetic Nanowire Metamaterials: Theory and Applications
ABSTRACT An overview of ferromagnetic nanowire (FMNW) metamaterials is presented. First, FMNW metamaterials are placed in the historical context of antique composites and 20th Century artificial dielectrics, and presented as an example of second-generation metamaterials following the microstructured metamaterials developed in the first part of the decade. Next, the fabrication processes of FMNW metamaterials and subsequent planar devices are detailed. It is then shown how the geometrical properties of the FMNW structure, such as the wire diameter and the wire nanodisk thicknesses, determine the dc and RF responses of the material. Upon this basis, the modeling of the metamaterial is presented, using a two-level approach where the microscopic (with respect to the wires) susceptibility is derived by solving the Landau-Lifshitz equation and the macroscopic (metamaterial) permittivity and permeability tensors are obtained by effective medium theory. Next, a review of FMNW microwave devices, such as circulators, isolators, and phase shifters, is provided, and the example of an FMNW dual-band edge-mode isolator is studied. Finally, spintronic effects and applications of FMNW metamaterials, such as dc to RF generators and detectors based on the spin-torque transfer phenomenon, are reviewed.
- [Show abstract] [Hide abstract]
ABSTRACT: This paper presents what, in the vision of the author, will be next-generation metamaterials for microwave systems. For this purpose, it first introduces some fundamentals on metamaterials and describes the different types of currently existing metamaterial structures, called micro-scale metamate-rials, in reference with their typical smallest dimension. Upon this basis, it presents a few micro-scale metamaterial properties, structures and principles, from the popular negative index of refraction, via various dispersion-engineered devices, to a very recent non-reciprocal magnet-less metamaterial. After pointing out the limitations of micro-scale metamaterial, the paper introduces next generation metamaterials, namely multi-scale metamaterials, which incorporate nano-scale and atomic-scale structures and substances. For the nano-scales, it presents the example of ferromagnetic nanowire metamaterials and their applications, while for the atomic scale it describes recent innovations in ferrite based structures, including a uniform waveguide CRLH leaky-wave antenna and a perfect electromagnetic conductor wall, as well as most recent graphene-based structures and devices. Finally, a tri-scale structure, incorporating a graphene atomic-scale, ferromagnetic wire nano-scale and a metasurface micro-scale is discussed. In conclusion, the paper suggests that, although technology is eminently unpredictable, the wealth of novel properties of metamaterials augurs a long and lasting impact of this area.
- [Show abstract] [Hide abstract]
ABSTRACT: Broadband and low beam squint anisotropic leaky wave antennaRadio Science 08/2011; 46(4). DOI:10.1029/2010RS004530 · 1.45 Impact Factor
Conference Paper: Field theory of electromagnetic metamaterials and beyond[Show abstract] [Hide abstract]
ABSTRACT: After a general definition and an overview of some historical milestones, we describe the two main theoretical approaches of metamaterials, the periodic structure and the polarization approaches, and point out their complementariness. We next present the concept of multi-scale and multi-substance structures as a novel paradigm for next-generation metamaterials, and discuss the subsequent multi-physics challenges and opportunities at the light of some examples.Microwave Symposium Digest (MTT), 2012 IEEE MTT-S International; 01/2012