Experimental Investigations of the Radio Wave Attenuation Processes through the Paths Leaving Buildings

One of the most important diagnostic problems multilayer dielectric materials and coatings is the development of methods for quantitative interpretation of the checkout results their electrophysical and geometric parameters. The results of a study of the potential informativeness of the multi-frequency radio wave method of surface electromagnetic waves during reconstruction of the electrophysical and geometric parameters of multilayer dielectric coatings are presented. The simulation model is presented that makes it possible to evaluate of the accuracy of reconstruction of the electrophysical and geometric parameters of multilayer dielectric coatings. The model takes into account the values of the electrophysical and geometric parameters of the coating, the noise level in the measurement data and the measurement bandwidth. The results of simulation and experimental investigations of reconstruction of the structure of relative permittivitties and thicknesses of single-layer and double-layer dielectric coatings with different thicknesses, with different values of the standard deviation (RMS) of the noise level in the measured attenuation coefficients of the surface slow electromagnetic wave are presented. Coatings based on the following materials were investigated: polymethyl methacrylate, F-4D PTFE, RO3010. The accuracy of reconstruction of the electrophysical parameters of the layers decreases with an increase in the number of evaluated parameters and an increase in the noise level. The accuracy of the estimates of the electrophysical parameters of the layers also decreases with a decrease in their relative permittivity and thickness. The results of experimental studies confirm the adequacy of the developed simulation model. The presented model allows for a specific measuring complex that implements the multi-frequency radio wave method of surface electromagnetic waves, to quantify the potential possibilities for the accuracy of reconstruction of the electrophysical and geometric parameters of multilayer dielectric materials and coatings. Experimental investigations and simulation results of a multilayer dielectric coating demonstrated the theoretical capabilities gained relative error permittivity and thickness of the individual layers with relative error not greater than 10 %, with a measurement bandwidth of 1 GHz and RMS of noise level 0,003–0,004.

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Контроль электрофизических параметров метаматериалов методом поверхностных электромагнитных волн

Дефектоскопия ◽

10.31857/s0130308221040060 ◽

2021 ◽

pp. 51-67

Author(s):

А.И. Казьмин ◽

П.А. Федюнин

Keyword(s):

Inverse Problem ◽

Electromagnetic Wave ◽

Radio Wave ◽

Local Control ◽

Negative Refraction ◽

Test Sample ◽

Experimental Investigations ◽

Surface Electromagnetic Wave ◽

New Radio ◽

Electrophysical Parameters

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 %.

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Quantum Mechanical Formulation of the Bloch NMR Flow Equations for the Analysis of Radio Wave Attenuation in Satellite Communication

Applied Physics Research ◽

10.5539/apr.v5n3p86 ◽

2013 ◽

Vol 5 (3) ◽

Author(s):

Rasheedat Bola Abdulrahim ◽

Michael Dada ◽

Bamidele Awojoyogbe

Keyword(s):

Radio Wave ◽

Satellite Communication ◽

Wave Attenuation ◽

Quantum Mechanical ◽

Flow Equations ◽

Mechanical Formulation ◽

Bloch Nmr Flow Equations

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Experimental investigations into the anisotropy of centimeter radio-wave backscattering from the surface of the sea at small slip angles

Radiophysics and Quantum Electronics ◽

10.1007/bf01038996 ◽

1988 ◽

Vol 31 (11) ◽

pp. 943-953 ◽

Cited By ~ 1

Author(s):

M. P. Gus'kov ◽

Yu. M. Zhidko ◽

V. V. Rodin ◽

I. A. Rusakova ◽

O. A. Shikhov

Keyword(s):

Radio Wave ◽

Experimental Investigations

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UHF Radio Wave Attenuation Factor Database

10.1063/1.2767034 ◽

2007 ◽

Author(s):

S. I. Khomenko ◽

V. L. Kostina ◽

I. M. Mytsenko ◽

A. N. Roenko

Keyword(s):

Radio Wave ◽

Wave Attenuation ◽

Attenuation Factor

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Empirical Model of Radio Wave Propagation in the Presence of Vegetation inside Greenhouses Using Regularized Regressions

Sensors ◽

10.3390/s20226621 ◽

2020 ◽

Vol 20 (22) ◽

pp. 6621

Author(s):

Dora Cama-Pinto ◽

Miguel Damas ◽

Juan Antonio Holgado-Terriza ◽

Francisco Manuel Arrabal-Campos ◽

Francisco Gómez-Mula ◽

...

Keyword(s):

Wave Propagation ◽

Radio Wave ◽

Empirical Model ◽

Precision Agriculture ◽

Wave Attenuation ◽

Multipath Propagation ◽

Field Tests ◽

Radio Wave Propagation ◽

Radio Waves ◽

Vegetation Height

Spain is Europe’s leading exporter of tomatoes harvested in greenhouses. The production of tomatoes should be kept and increased, supported by precision agriculture to meet food and commercial demand. The wireless sensor network (WSN) has demonstrated to be a tool to provide farmers with useful information on the state of their plantations due to its practical deployment. However, in order to measure its deployment within a crop, it is necessary to know the communication coverage of the nodes that make up the network. The multipath propagation of radio waves between the transceivers of the WSN nodes inside a greenhouse is degraded and attenuated by the intricate complex of stems, branches, leaf twigs, and fruits, all randomly oriented, that block the line of sight, consequently generating a signal power loss as the distance increases. Although the COST235 (European Cooperation in Science and Technology - COST), ITU-R (International Telecommunications Union—Radiocommunication Sector), FITU-R (Fitted ITU-R), and Weisbberger models provide an explanation of the radio wave propagation in the presence of vegetation in the 2.4 GHz ICM band, some significant discrepancies were found when they are applied to field tests with tomato greenhouses. In this paper, a novel method is proposed for determining an empirical model of radio wave attenuation for vegetation in the 2.4 GHz band, which includes the vegetation height as a parameter in addition to the distance between transceivers of WNS nodes. The empirical attenuation model was obtained applying regularized regressions with a multiparametric equation using experimental signal RSSI measurements achieved by our own RSSI measurement system for our field tests in four plantations. The evaluation parameters gave 0.948 for R2, 0.946 for R2 Adj considering 5th grade polynomial (20 parameters), and 0.942 for R2, and 0.940 for R2 Adj when a reduction of parameters was applied using the cross validation (15 parameters). These results verify the rationality and reliability of the empirical model. Finally, the model was validated considering experimental data from other plantations, reaching similar results to our proposed model.

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