Контроль электрофизических параметров метаматериалов методом поверхностных электромагнитных волн

Development of metamaterials has led to the search and choice of effective methods of radio-wave nondestructive testing of their electrophysical parameters. The existing approaches to testing based on extracted of effective electrophysical parameters of metamaterials from the coefficients of reflection and transmission of an electromagnetic wave have low reliability and don't provide their local control. We present the new radio-wave method of local control of complex dielectric permittivity and magnetic permeability, as well as the thickness of metamaterial plate on a metal substrate with surface microwaves. The method is based on the solution of inverse problem in the determination of effective electrophysical parameters of metamaterial from the frequency dependence of the attenuation coefficient of the field of a slow surface electromagnetic wave excited in a test sample. The electrophysical parameters of the metamaterial are represented as parametric frequency functions in accordance with the Drude-Lorentz models of dispersion, and the solution of the inverse problem is reduced to minimizing the objective function constructed based on the discrepancy between the experimental and design theoretical values of the attenuation coefficients of surface electromagnetic wave fields on a grid of discrete frequencies. The structure of a measuring complex that implements the proposed method of control is proposed. For the numerical and experimental verification of the method, a sample of a metamaterial plate based on SRR elements with a negative refraction region in the frequency band 10.06–10.64 GHz was investigated. Experimental investigations of the metamaterial demonstrated the theoretical capabilities gained with measurement of the local electrophysical parameters with relative error not greater 10 %.

Excitation of Surface Electromagnetic Waves at the Silver/NaCl Aqueous Solution Interface

The results of a study of the dynamics of the excitation angle of a surface electromagnetic wave (SEW) at the interface between a silver/NaCl aqueous solution of concentrations 10−3, 10−4, 10−6 and 10−10 M are presented. It is shown that the rate of change in the excitation angle of SEW is proportional to the concentration of the solution up to a dilution of 10−10 M. The observed effect is explained by the formation of silver chloride on the surface of the silver film as a result of the interaction of solution ions with nanoscale clusters of the silver film. The proposed technique for measuring the dynamics of the excitation angle of SEW can be used for a comparative analysis of the concentrations of highly dilute solutions, as well as for studying the formation and dynamics of transition layers and physicochemical processes in the near-surface regions.

Microwave Magnon-Plasmon-Polaritons in the Ferromagnetic Metal–Screened Insulator Structure

A possibility for surface magnon–plasmon–polaritons (SMPPs)–coupled microwave oscillations of magnetization, electron density, and electromagnetic field–to exist in real ferromagnetic metal–insulator–ideal non-magnetic metal structures has been analyzed theoretically. The developed theory predicts that the effective formation of SMPPs is possible only at certain values of the external dc magnetic field and must be accompanied by a shift in the characteristic frequency of the resonance plasmon-polariton systems. A theoretical estimation of the frequency shift for SMPPs in the structure “surface electromagnetic wave resonator made of permalloy–vacuum–ideal metal” gives a value of ±45 MHz for a resonator with a characteristic frequency of 10 GHz, which seems sufficient for this effect to be observed experimentally.

Control of defects in the multilayer dielectric materials and coatings in the microwave range

The development of modern engineering is inextricably linked with the development of the new types of multilayer dielectric materials. Existing radio wave methods for monitoring interlayer defects in such materials exhibit low accuracy in reconstructing the geometric parameters of defects. The results of studying extended interlayer defects in the three-layer coating consisting of polymethyl methacrylate, F-4D PTFE, and semi-hard rubber by the method of surface electromagnetic waves are presented. The method is based on the solution of inverse problems in the reconstruction of the geometric parameters of extended interlayer defects of special multilayer materials and coatings from the frequency dependence of the attenuation coefficient of the field of a slow surface electromagnetic wave. Unlike the methods that make use from the complex reflection coefficient we proposed to increase the accuracy of the reconstruction of the geometric parameters of extended interlayer defects taking into account the linear frequency dependence of the attenuation coefficient as well as reducing the number of fixed measurement frequencies. Moreover, the determination procedure is rather simple, since only the field strength of the surface electromagnetic wave is measured, and there is no need for phase measurements. Experimental data obtained on a multifrequency measuring complex in the range of 10 – 11 GHz were used for reconstruction of the interlayer defects in the coating under study. The developed method provided a relative error of thickness estimation below 10%. The proposed method approach can be used in studying multilayer dielectric coatings on the metal for detection of delamination in the lack of glue or poor adhesion between the layers. The developed method is also suitable for control of the defects in semiconductors, ferrite and composite materials.