Electromagnetic wave depolarization behaviour at different frequencies for various dielectric materials

2007 ◽  
Author(s):  
Y. Lostanlen ◽  
T. Tenoux
Keyword(s):  
Electromagnetic Wave ◽  
Dielectric Materials ◽  
Wave Depolarization

ELECTROMAGNETIC WAVE PROPAGATION CHARACTERISTICS IN A ONE-DIMENSIONAL METALLIC PHOTONIC CRYSTAL

2008 ◽  
Vol 17 (03) ◽  
pp. 255-264 ◽  
Author(s):  
ARAFA H. ALY ◽  
SANG-WAN RYU ◽  
CHIEN-JANG WU
Keyword(s):  
Wave Propagation ◽  
Electromagnetic Wave ◽  
Photonic Crystal ◽  
Transfer Matrix Method ◽  
Electromagnetic Wave Propagation ◽  
Plasma Frequency ◽  
Dielectric Materials ◽  
Propagation Characteristics ◽  
One Dimensional ◽  
Metallic Photonic Crystal

We theoretically studied electromagnetic wave propagation in a one-dimensional metal/dielectric photonic crystal (1D MDPC) consisting of alternating metallic and dielectric materials by using the transfer matrix method. We performed numerical analyses to investigate the propagation characteristics of a 1D MDPC. We discuss the details of the calculated results in terms of the electron density, the thickness of the metallic layer, different kinds of metals, and the plasma frequency.

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

2020 ◽  
Vol 86 (2) ◽  
pp. 37-43
Author(s):  
A. I. Kaz’min ◽  
P. A. Fedyunin
Keyword(s):  
Electromagnetic Wave ◽  
Frequency Dependence ◽  
Attenuation Coefficient ◽  
Electromagnetic Waves ◽  
Dielectric Materials ◽  
Geometric Parameters ◽  
Microwave Range ◽  
Surface Electromagnetic Wave ◽  
Phase Measurements ◽  
Multilayer Dielectric

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.

scholarly journals Quality control of substances by electromagnetic sensing in a waveguide

2020 ◽  
Keyword(s):  
Dielectric Constant ◽  
Electromagnetic Wave ◽  
Standing Wave ◽  
Dielectric Materials ◽  
Complex Dielectric Constant ◽  
Microwave Range ◽  
Dielectric Sample ◽  
Layered Dielectric ◽  
Dielectric Structures ◽  
Non Destructive

Relevance. The problems of remote non-destructive determination and control of quality indicators of a wide variety of material environments, in particular, household and food products, are relevant practically for all areas of the national economy, science and technology. The relevance of scientific research in the field of dielectrometry in the microwave range is also due to the needs for the development of high technologies in medicine and health care, the national economy in real time. The aim of this work is to develop the method of microwave waveguide dielectrometry based on the application of the theory of multilayer plane-layered dielectric structures to the determination of the complex dielectric constant of a substance from the values ​​of the standing wave ratio of the samples under study in a waveguide at two close frequencies. Materials and methods. The research is based on well-studied phenomena of interference of electromagnetic waves on multilayer plane-layered dielectric structures. By using a mathematical model of the phenomenon of interference of a plane electromagnetic wave on a three-layer dielectric structure, the ambiguity of determining the complex dielectric constant of a substance by the classical method of waveguide dielectrometry in the microwave range by measuring the standing wave ratio of a dielectric sample placed in the waveguide and the phase angle of the reflection coefficient is overcome. Results. A method is proposed for ensuring the unambiguity of determining the complex dielectric constant of a substance in waveguide dielectrometry on the basis of the theory of multilayer plane-layered dielectric structures. The method leads to an explicit expression for the complex reflection coefficient of an electromagnetic wave from the investigated dielectric sample placed in a rectangular waveguide. The complex dielectric constant of a substance is determined from the values ​​of the standing wave ratio at two close frequencies in the microwave range. By the found value of the dielectric constant and the tangent of the dielectric loss angle, the quality parameter of the substance is determined by comparing and optimizing two objective functions, including the arrays of reference values ​​of the complex dielectric constant obtained in the course of measurements and compiled in advance, and by comparing and optimizing the third objective function, previous functions. As an example of an indicator of the quality of a substance, the specific heat of combustion of coal was determined. Conclusions. The proposed method for determining the complex dielectric constant and quality indicators of dielectric materials in the microwave frequency range has been tested in the case of various types of coals, its efficiency has been proven and the reliability of the results has been proven. The method and the devices and software implemented on its basis are promising for non-destructive express control of dielectric materials and media.

Tunable Sensing Property of 1D Periodic Structure with Defect of Liquid Crystal Sandwiched by Metallic Layers

2019 ◽  
Vol 17 (10) ◽  
pp. 800-803
Author(s):  
Pawan Singh ◽  
Krishan Pal ◽  
Narinder Kumar ◽  
Sudesh K. Singh ◽  
Khem B. Thapa ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electromagnetic Wave ◽  
Liquid Crystal ◽  
Periodic Structure ◽  
Transfer Matrix Method ◽  
Incident Angle ◽  
Dielectric Materials ◽  
Absorption Properties ◽  
One Dimensional ◽  
Absorption Defect

In this paper, we have investigated the optical properties of one-dimensional periodic structure of dielectric materials with defect of liquid crystal (LC) sandwiched with two silver (Ag) layers. The transmission, reflection and absorption properties of considered periodic structure have calculated theoretically using transfer matrix method (TMM). Our study reports that the tunability of absorption defect peak of the defect periodic structure is achieved by the variation in the incident angle of electromagnetic wave. The obtained result suggests that such defect periodic structure may be used as tunable sensor and filter devices.

Optimization of two-layer electromagnetic wave absorbers composed of magnetic and dielectric materials in gigahertz frequency band

2005 ◽  
Vol 98 (8) ◽  
pp. 084903 ◽  
Author(s):  
Yanfei He ◽  
Rongzhou Gong ◽  
Yan Nie ◽  
Huahui He ◽  
Zhensheng Zhao
Keyword(s):  
Electromagnetic Wave ◽  
Frequency Band ◽  
Dielectric Materials
Sign in / Sign up

Export Citation Format

Share Document