scholarly journals Multi-modal Scattering and Propagation Through Several Close Periodic Grids

2021 ◽  
Author(s):  
Christoph Kohlberger
Keyword(s):  
Electromagnetic Waves ◽  
Metal Layer ◽  
Reflection And Transmission ◽  
Transmission Parameters ◽  
Electromagnetic Interactions ◽  
Grating Lobe ◽  
Full Wave ◽  
S Parameter ◽  
The Individual ◽  
Surface Admittance

<div>The presented method describes reflection and transmission of electromagnetic waves at multiple closely stacked metal grids using multi-modal S-parameter propagation. For that, the surface admittance of every metal layer was determined, through a novel semi-analytic approach that uses simple Fourier transformations instead of solving an integral equation. The modal components of this surface admittance were used to express the generalized scattering matrices of the individual grids. By applying multi-modal propagation techniques to the resulting scattering parameters, it was possible to model the electromagnetic interactions within a multilayer stack of periodic impedance sheets. Resulting reflection and transmission parameters perfectly matched the corresponding full-wave simulations even above the grating lobe regime. In the end, the universality of the proposed method was proven on a layer stack, connected to lumped components.</div>

scholarly journals Multi-modal Scattering and Propagation Through Several Close Periodic Grids

2021 ◽  
Author(s):  
Christoph Kohlberger
Keyword(s):  
Electromagnetic Waves ◽  
Metal Layer ◽  
Reflection And Transmission ◽  
Transmission Parameters ◽  
Electromagnetic Interactions ◽  
Grating Lobe ◽  
Full Wave ◽  
S Parameter ◽  
The Individual ◽  
Surface Admittance

<div>The presented method describes reflection and transmission of electromagnetic waves at multiple closely stacked metal grids using multi-modal S-parameter propagation. For that, the surface admittance of every metal layer was determined, through a novel semi-analytic approach that uses simple Fourier transformations instead of solving an integral equation. The modal components of this surface admittance were used to express the generalized scattering matrices of the individual grids. By applying multi-modal propagation techniques to the resulting scattering parameters, it was possible to model the electromagnetic interactions within a multilayer stack of periodic impedance sheets. Resulting reflection and transmission parameters perfectly matched the corresponding full-wave simulations even above the grating lobe regime. In the end, the universality of the proposed method was proven on a layer stack, connected to lumped components.</div>

scholarly journals Influence of Rugate Filters on the Spectral Manifestation of Tamm Plasmon Polaritons

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1282
Author(s):  
Victor Reshetnyak ◽  
Igor Pinkevych ◽  
Timothy Bunning ◽  
Dean Evans
Keyword(s):  
Refractive Index ◽  
Band Gap ◽  
External Medium ◽  
Metal Layer ◽  
Refractive Index Profile ◽  
Spectral Position ◽  
Index Profile ◽  
Reflection And Transmission ◽  
Rugate Filter ◽  
Plasmon Polaritons

This study theoretically investigated light reflection and transmission in a system composed of a thin metal layer (Ag) adjacent to a rugate filter (RF) having a harmonic refractive index profile. Narrow dips in reflectance and peaks in transmittance in the RF band gap were obtained due to the excitation of a Tamm plasmon polariton (TPP) at the Ag–RF interface. It is shown that the spectral position and magnitude of the TPP dips/peaks in the RF band gap depend on the harmonic profile parameters of the RF refractive index, the metal layer thickness, and the external medium refractive index. The obtained dependences for reflectance and transmittance allow selecting parameters of the system which can be optimized for various applications.

The Reflection and Transmission of Electromagnetic Waves by a Chiral Slab

1992 ◽  
Vol 39 (6) ◽  
pp. 1321-1330 ◽  
Author(s):  
H. Cory ◽  
I. Rosenhouse
Keyword(s):  
Electromagnetic Waves ◽  
Reflection And Transmission

Analysis for Scattering of Non-homogeneous Medium by Time Domain Volume Shooting and Bouncing Rays

2021 ◽  
Vol 36 (3) ◽  
pp. 245-251
Author(s):  
Jun Li ◽  
Huaguang Bao ◽  
Dazhi Ding
Keyword(s):  
Time Domain ◽  
Electromagnetic Scattering ◽  
Electromagnetic Waves ◽  
High Efficiency ◽  
Homogeneous Medium ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Transient Electromagnetic ◽  
Frequency Domain Methods ◽  
Scattered Fields

In order to evaluate scattering from hypersonic vehicles covered with the plasma efficiently, time domain volume shooting and bouncing rays (TDVSBR) is first introduced in this paper. The new method is applied to solve the transient electromagnetic scattering from complex targets, which combines with non-homogeneous dielectric and perfect electric conducting (PEC) bodies. To simplify the problem, objects are discretized into tetrahedrons with different electromagnetic parameters. Then the reflection and transmission coefficients can be obtained by using theory of electromagnetic waves propagation in lossy medium. After that, we simulate the reflection and transmission of rays in different media. At last, the scattered fields or radiation are solved by the last exiting ray from the target. Compared with frequency-domain methods, time-domain methods can obtain the wideband RCS efficiently. Several numerical results are given to demonstrate the high efficiency and accuracy of this proposed scheme.

Variability in rainfall information derived from collocated microwave links

2021 ◽  
Author(s):  
Anna Špačková ◽  
Vojtěch Bareš ◽  
Martin Fencl
Keyword(s):  
Electromagnetic Waves ◽  
Rainfall Intensity ◽  
Weather Condition ◽  
Estimation Accuracy ◽  
Response Patterns ◽  
Spatial Coverage ◽  
Telecommunications Network ◽  
Path Lengths ◽  
Point To Point ◽  
The Individual

&lt;p&gt;In the field of hydrology, there is a significant demand for high spatial-temporal resolution of rainfall information that can be met by commercial microwave links (CMLs). CMLs are commonly used as a backhaul of telecommunications network with favourable spatial coverage especially in urbanized areas. CMLs are point-to-point radio connections operating at frequencies where attenuation of electromagnetic waves can be related to the rainfall intensity.&lt;/p&gt;&lt;p&gt;The ability of CMLs to assess rainfall intensity is determined by hardware parameters and path lengths of CMLs. The CML operates at various frequencies with horizontal or vertical polarization, moreover, link paths have lengths ranging from hundreds of meters up to kilometres. The characteristics of the rainfall needs to be reflected as they have impact on the errors (de Vos et al., 2019). Even collocated CMLs can detect considerably dissimilar rainfall information. To increase effectivity of rainfall information retrieval it is crucial to understand uncertainties arising from diversity of CML characteristics.&lt;/p&gt;&lt;p&gt;This study evaluates collocated CMLs that are assumed to be affected by the same weather condition. Having identical CML characteristics (as well as the propagations of the signals), it is expected to observe the same response patterns in the attenuated signals. Any disagreement could be caused by random error, sensitivity to the rainfall intensities, and/or hardware reaction to the condition (e.g. sensitivity of the antenna radome to the rainfall splash). Therefore, the role of arrangement of the direction of rainfall field advection and position of the collocated link paths is considered. The magnitude of disagreement between different groups of collocated links could be specified based on their characteristics. Oppositely, for collocated links under the same conditions but with different characteristics, the attributes of the individual CMLs are suspected for the disagreement.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;References&lt;/p&gt;&lt;p&gt;de Vos, L. W., Overeem, A., Leijnse, H., and Uijlenhoet, R. (2019). Rainfall Estimation Accuracy of a Nationwide Instantaneously Sampling Commercial Microwave Link Network: Error Dependency on Known Characteristics. Journal of Atmospheric and Oceanic Technology 36, 7, 1267-1283. https://doi.org/10.1175/JTECH-D-18-0197.1&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;This study was supported by the project SpraiLINK 20-14151J of the Czech Science Foundation.&lt;/p&gt;

scholarly journals FULL WAVE MODELING OF BRAIN WAVES AS ELECTROMAGNETIC WAVES (Invited Paper)

2015 ◽  
Vol 151 ◽  
pp. 95-107 ◽  
Author(s):  
Sidharath Jain ◽  
Raj Mittra ◽  
Joe Wiart
Keyword(s):  
Electromagnetic Waves ◽  
Wave Modeling ◽  
Brain Waves ◽  
Full Wave
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