New Type Of Metamaterial Research Articles

Print-and-Spray Electromechanical Metamaterials.

Many types of novel stretchable and conductive materials have been developed, but all exhibit a large increase in resistance upon stretching. In this article, the design and fabrication methods of two types of electromechanical metamaterials are presented, where the first has an invariant electrical resistance and the second has a decreasing electrical resistance upon elongation. The metamaterials can be fabricated by a few rapid and simple steps: a flexible polymer part is three-dimensional printed and sprayed with a conductive coating. Parametric optimization of the geometrical dimensions of the resistance invariant structure yielded a metamaterial with a nearly constant electrical resistance up to ∼1100% of tensile strain, whose behavior could be predicted using the finite element method. The second metamaterial had a resistance that reduced by as much as 38% over a displacement of 600 μm. The design principles of these new types of metamaterials can open new possibilities for high-performance soft robots and flexible electronics.

Feature issue introduction: Metamaterials, Photonic Crystals and Plasmonics

With the ability to manipulate and precisely tailor the micro- and nanostructures with sizes that are comparable to or smaller than the wavelength of light, unique optical properties beyond those offered by natural materials can be achieved in various nanophotonic platforms including plasmonics, photonic crystals and metamaterials. In this feature issue, fifteen papers are included with broad coverage of the cutting-edge research in the fields ranging from optical sensing, structure-enhanced absorption, novel non-metallic plasmonic materials, structure-modified optical transmission to new types of metamaterials, topological and quantum photonics.

Microwave Filters Based on the Structures with Resonators in Parallel Channels as Metamaterial Cells

Background . Many of the properties of metamaterials are similar to those found in filters with mutually detuned by frequency unrelated resonators. The bridge filters are used as a low-frequency prototypes of such microwave filters. For further development and design of new types of metamaterials it is necessary to establish an analogy between metamaterials and filters with mutually detuned by frequency unrelated resonators. Objective. Creating a model of metamaterials based on the bandstop microwave filters with mutually detuned resonators and on the low-frequency prototypes. Methods . Checking the equivalence of metamaterials characteristics and microwave filters with mutually detuned resonators, identifying their inherent laws (oscillation types in parallel channels, location of the attenuation poles above or below the bandwidth), which appear regardless of the types of resonators, studying the possibility of using prototype bridge filters for modeling of metamaterials. Results. The basic model of an 8-pole network with resonators in parallel channels has been studied in detail. Analytical expressions are obtained for the transmission and reflection coefficients for all inputs of an 8-pole network. The 4-pole networks implemented on the basis of the aforementioned basic model are investigated. Experimental studies are performed that confirm the adequacy of analytical models. An analogy between metamaterials and microwave filters with mutually detuned resonators is established, the possibility of the use as a low-frequency prototype bridge bandpass filters is shown. Conclusions . Microwave filters with mutually detuned resonators can be used for modeling of metamaterials, and bridge bandpass filters – as low-frequency prototypes, which design techniques are well developed.

Resonator-Based Filters with Frequency Modes Close to Metamaterial Cells

Background . Many of the properties of metamaterials are similar to those found in the filter on mutually detuned frequency and unrelated resonators. The bridge filters are used as a low-frequency prototypes of such microwave filters. It is important to establish an analogy between metamaterials and filters on mutually detuned frequency and unrelated resonators for further development and design of new types of metamaterials. Objective. A central objective is a model development of metamaterials based on band-exclusive microwave filters on mutually detuned resonators, and the low-frequency-based prototypes. Methods. Characteristic equivalence test of metamaterials to microwave filters on mutually detuned resonators, their specific dependencies reveal (the modes in parallel channels, the locations of the attenuation poles above or below the bandwidth), manifested regardless of the types of resonators, the study of the possibility of the bridge filter prototypes using for metamaterials simulation. Results. The analogy between metamaterials and microwave filters on mutually detuned resonator is specified, the possibility of bridge bandpass filter use as low-frequency prototypes is shown. Conclusions . Microwave filters on mutually detuned resonators, and bridge band-pass filters as low-frequency prototypes, design techniques of which are well established, can be used for metamaterial modeling.

An Electromagnetic Sensor with a Metamaterial Lens for Nondestructive Evaluation of Composite Materials.

This paper proposes the study and implementation of a sensor with a metamaterial (MM) lens in electromagnetic nondestructive evaluation (eNDE). Thus, the use of a new type of MM, named Conical Swiss Rolls (CSR) has been proposed. These structures can serve as electromagnetic flux concentrators in the radiofrequency range. As a direct application, plates of composite materials with carbon fibers woven as reinforcement and polyphenylene sulphide as matrix with delaminations due to low energy impacts were examined. The evaluation method is based on the appearance of evanescent modes in the space between carbon fibers when the sample is excited with a transversal magnetic along z axis (TMz) polarized electromagnetic field. The MM lens allows the transmission and intensification of evanescent waves. The characteristics of carbon fibers woven structure became visible and delaminations are clearly emphasized. The flaws can be localized with spatial resolution better than λ/2000.

Deformed omega resonator and its application to microwave filters

This communication introduces a new resonant structure called Deformed Omega Resonator. An equivalent circuit model is presented and its application in filters is demonstrated. However, its usefulness as a metamaterial unit cell is as important, thereby, it can be used for developing new types of metamaterials in future studies. With proper design parameters ensuring acceptable aspect ratio of elements for validation of applied formulas, the model seems flawless with less than 4% of error. The results have been experimentally verified and we observed their good agreement with the theory and simulation data. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1447–1451, 2015

Band split in multiband all-dielectric left-handed metamaterials

In this paper, we propose and fabricate multiband all-dielectric left-handed metamaterials (ADMs) in the X-band microwave regime. The ADMs are fabricated by a combination of dielectric resonators in shapes of cubes and rods. The ADMs can exhibit two left-handed pass bands while the rods contact the sidewalls of the waveguide. A band split phenomenon is observed when the boundary conditions of dielectric rods change. The two pass bands can diverge into three left-handed pass bands when the rods do not contact the waveguide. By using field analysis and dielectric resonator theory, we prove that the boundary conditions have a strong influence on the resonant modes of the rod resonator, which plays key roles in left-handedness. The boundary tuned resonant modes can broaden our ways of designing new types of metamaterials.

Electromagnetic non-destructive evaluation using metamaterials

This paper proposes the study and implementation of metamaterials in electromagnetic non-destructive examination; these materials can serve as electromagnetic flux concentrators in the radio frequency range. Thus, the use of new types of metamaterials, namely conical Swiss roll, is proposed. Here, we present a method of extracting the necessary parameters (effective magnetic permeability and the frequency) from the data obtained by measuring network parameters. Due to the fact that conical Swiss rolls can serve as radio frequency flux concentrators, they can be used in the fabrication of electromagnetic lenses, being designed on the basis of Fourier optic principles. As a direct application, carbon fibre reinforced plastic (CFRP) plates with and without delaminations, created by impacts with low energy, were examined by means of electromagnetic transducers with a metamaterial lens. The characteristics of a carbon fibre woven structure become visible and the delaminations are clearly emphasised.