scholarly journals Asymptotic Analysis of Transverse Magnetic Multiple Scattering by the Diffraction Grating of Penetrable Cylinders at Oblique Incidence

2011 ◽  
Vol 2011 ◽  
pp. 1-30 ◽  
Author(s):  
Ömer Kavaklıoğlu ◽  
Roger Henry Lang
Keyword(s):  
Multiple Scattering ◽  
Oblique Incidence ◽  
Asymptotic Series ◽  
Normal Incidence ◽  
Transverse Magnetic ◽  
Circular Cylinders ◽  
Scattering Coefficients ◽  
Asymptotic Equations ◽  
Grating Spacing ◽  
Asymptotic Forms

We have presented a derivation of the asymptotic equations for transverse magnetic multiple scattering coefficients of an infinite grating of penetrable circular cylinders for obliquely incident plane electromagnetic waves. We have first deducted an “Ansatz” delineating the asymptotic behavior of the transverse magnetic multiple scattering coefficients associated with the most generalized condition of oblique incidence (Kavaklıoğlu, 2000) by exploiting Schlömilch series corresponding to the special circumstance that the grating spacing is much smaller than the wavelength of the incident electromagnetic radiation. The validity of the asymptotic equations for the aforementioned scattering coefficients has been verified by collating them with the Twersky's asymptotic equations at normal incidence. Besides, we have deduced the consequences that the asymptotic forms of the equations at oblique incidence acquired in this paper reduce to Twersky's asymptotic forms at normal incidence by expanding the generalized scattering coefficients at oblique incidence into an asymptotic series as a function of the ratio of the cylinder radius to the grating spacing.

scholarly journals Exact Matrix Representation of the Transverse Magnetic Multiple Scattering of Obliquely Incident Plane Waves by the Diffraction Grating of Penetrable Cylinders

2012 ◽  
Vol 2012 ◽  
pp. 1-17
Author(s):  
Ömer Kavaklıoğlu ◽  
Roger Henry Lang
Keyword(s):  
Multiple Scattering ◽  
Diffraction Grating ◽  
Plane Waves ◽  
Transverse Magnetic ◽  
Circular Cylinders ◽  
Scattering Coefficients ◽  
Obliquely Incident ◽  
Incident Plane ◽  
Inversion Procedure ◽  
Exact Matrix

“An exact matrix conformation model” associated with the equations describing the exact behavior of the Fourier-Bessel multiple scattering coefficients of the diffraction grating consisting of an infinite number of infinitely long parallel penetrable circular cylinders, corresponding to the obliquely incident transverse-magnetic plane waves in “Twersky-Wait-Kavaklıoğlu representation,” originally excogitated in (Kavaklıoğlu, 2000), is acquired, and the exact solution for “the Fourier-Bessel multiple scattering coefficients of the diffraction grating at oblique incidence” is obtained by a matrix inversion procedure.

Calculation of the Ion Optical Properties of Inhomogeneous Magnetic Sector Fields Part 3: Oblique Incidence and Exit at Curved Boundaries

1959 ◽  
Vol 14 (9) ◽  
pp. 822-827 ◽  
Author(s):  
H. A. Tasman ◽  
A. J. H. Boerboom ◽  
H. Wachsmuth
Keyword(s):  
Oblique Incidence ◽  
Normal Incidence ◽  
Second Order ◽  
Resolving Power ◽  
High Mass ◽  
Curved Boundaries ◽  
Magnetic Sector ◽  
Mass Resolving Power ◽  
Mass Dispersion ◽  
Fringing Fields

In previous papers 1.2we presented the radial second order imaging properties of inhomogeneous magnetic sector fields with normal incidence and exit at plane boundaries. These fields may provide very high mass resolving power and mass dispersion without increase in radius or decrease of slit widths. In the present paper the calculations are extended to include the effect of oblique incidence and exit at curved boundaries. The influence of the fringing fields on axial focusing when the boundaries are oblique, is accounted for. It is shown that the second order angular aberration may Le eliminated by appropriate curvature of the boundaries.

scholarly journals Mathematical analogies in physics. Thin-layer wave theory

2014 ◽  
Vol 57 (1) ◽  
Author(s):  
José M. Carcione ◽  
Vivian Grünhut ◽  
Ana Osella
Keyword(s):  
Quantum Mechanics ◽  
Thin Layer ◽  
Quantum Physics ◽  
Constitutive Relations ◽  
Normal Incidence ◽  
Wave Theory ◽  
Transverse Magnetic ◽  
Momentum Conservation ◽  
Tunnel Effect ◽  
Basic Equations

<p>Field theory applies to elastodynamics, electromagnetism, quantum mechanics, gravitation and other similar fields of physics, where the basic equations describing the phenomenon are based on constitutive relations and balance equations. For instance, in elastodynamics, these are the stress-strain relations and the equations of momentum conservation (Euler-Newton law). In these cases, the same mathematical theory can be used, by establishing appropriate mathematical equivalences (or analogies) between material properties and field variables. For instance, the wave equation and the related mathematical developments can be used to describe anelastic and electromagnetic wave propagation, and are extensively used in quantum mechanics. In this work, we obtain the mathematical analogy for the reflection/refraction (transmission) problem of a thin layer embedded between dissimilar media, considering the presence of anisotropy and attenuation/viscosity in the viscoelastic case, conductivity in the electromagnetic case and a potential barrier in quantum physics (the tunnel effect). The analogy is mainly illustrated with geophysical examples of propagation of S (shear), P (compressional), TM (transverse-magnetic) and TE (transverse-electric) waves. The tunnel effect is obtained as a special case of viscoelastic waves at normal incidence.</p>

scholarly journals Electrically Tunable Broadband Terahertz Absorption with Hybrid-Patterned Graphene Metasurfaces

Nanomaterials ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 562 ◽  
Author(s):  
Longfang Ye ◽  
Xin Chen ◽  
Guoxiong Cai ◽  
Jinfeng Zhu ◽  
Na Liu ◽  
...  
Keyword(s):  
Incident Angle ◽  
Single Layer ◽  
Normal Incidence ◽  
Transverse Magnetic ◽  
Single Layer Graphene ◽  
Terahertz Waves ◽  
Broadband Absorption ◽  
Terahertz Sensing ◽  
Axisymmetric Configuration ◽  
Broadband Terahertz

We numerically demonstrate a broadband terahertz (THz) absorber that is based on a hybrid-patterned graphene metasurface with excellent properties of polarization insensitivity, wide-angle, and active tunability. Our design is made up of a single-layer graphene with periodically arranged hybrid square/disk/loop patterns on a multilayer structure. We find that broadband absorption with 90% terahertz absorbance and the fractional bandwidth of 84.5% from 1.38 THz to 3.4 THz can be achieved. Because of the axisymmetric configuration, the absorber demonstrates absolute polarization independence for both transverse electric (TE) and transverse magnetic (TM) polarized terahertz waves under normal incidence. We also show that a bandwidth of 60% absorbance still remains 2.7 THz, ranging from 1.3 THz to 4 THz, for a wide incident angle ranging from 0° to 60°. Finally, we find that by changing the graphene Fermi energy from 0.7 eV to 0 eV, the absorbance of the absorbers can be easily tuned from more than 90% to lower than 20%. The proposed absorber may have promising applications in terahertz sensing, detecting, imaging, and cloaking.

DESIGN AND PERFORMANCE SIMULATION OF STRUCTURED MICROWAVE ABSORBER BASED ON CONDUCTIVE ABS 3D PRINTING FILAMENT

2021 ◽  
Vol 4 (4) ◽  
pp. 425-431
Author(s):  
M. B. Abdullahi ◽  
M. H. Ali
Keyword(s):  
3D Printing ◽  
Absorption Rate ◽  
Low Cost ◽  
Normal Incidence ◽  
Transverse Magnetic ◽  
Microwave Absorber ◽  
Shielding Effectiveness ◽  
Geometrical Structures ◽  
Detection Techniques ◽  
Absorption Characteristics

Electromagnetic absorbing materials with broadband, lightweight, wide-angle, and polarization-insensitive characteristics attracts extensive research interest recently, due to rapid advancement in radar detection techniques and communication devices. Three-dimensional printing is being employed to realize cost-effective structured electromagnetic absorbers that has lately become a common practice of improving radar stealth performance and shielding effectiveness. Structured absorbers permit realization of desired absorption characteristics by careful design of their geometrical structures. In this study, a two-layer structured microwave absorber using conductive ABS polymer is simulated. COMSOL Multiphysics environment is used to investigate the absorption characteristics of the designed structure. Under normal incidence, simulation results revealed at least 90% of absorption from 7.2 GHz to 18.0 GHz for both Transverse Electric (TE) and Transverse Magnetic (TM) polarizations. Oblique incidence results for TE polarization indicate that the absorption rate is more than 90% in the whole range of 7.2–18 GHz frequency band up to 450 while the absorption rate is more than 80% for 600 incident waves. The absorption rate is more than 90% in the 7.2-18 GHz range for oblique incidences of up to 300 only for TM polarization, but greater than 70% at 450 incident angles. Additionally, the designed absorber is independent of the polarization of the incident wave. As a result of the exhibited favourable absorption characteristics, the studied absorber provides great potentials for its experimentation and practicability using the low-cost 3D printing manufacturing process

Numerical Simulation of Penetration Effect of Spherical Fragment on Square Honeycomb Sandwich Plate

2011 ◽  
Vol 474-476 ◽  
pp. 1869-1873 ◽  
Author(s):  
Tao Wang ◽  
Wen Li Yu ◽  
San Qiang Dong ◽  
Yun Liang Gao
Keyword(s):  
Oblique Incidence ◽  
Sandwich Plate ◽  
Normal Incidence ◽  
Impact Angle ◽  
Damage Effect ◽  
Penetration Effect ◽  
Honeycomb Sandwich ◽  
Honeycomb Sandwich Plate ◽  
Solid Plate ◽  
Active Fragment

In this paper, a spherical fragment penetrating to square honeycomb sandwich plate and solid plate which has the same mass as sandwich plate are simulated by LS-DYNA code. The fragment impacts plates at normal incidence and oblique incidence with 30º impact angle at the velocity of 300m/s, 350m/s, 380m/s, 400m/s, 450m/s and 500m/s separately. And the damage pattern of sandwich plate, the acceleration of fragment and the energy absorption of sandwich plate are acquired. For sandwich plate, the acceleration of fragment is less than that of solid plate and the internal energy absorbed is larger that that of solid plate. The result can be used to design new active fragment to improve the damage effect to sandwich plate.

scholarly journals Reconfigurable honeycomb metamaterial absorber having incident angular stability

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Javad Shabanpour ◽  
Sina Beyraghi ◽  
Homayoon Oraizi
Keyword(s):  
Electromagnetic Interference ◽  
Oblique Incidence ◽  
Mechanical Performance ◽  
Incident Angle ◽  
Normal Incidence ◽  
Metallic Phase ◽  
Metamaterial Absorber ◽  
Angular Stability ◽  
Ohmic Losses ◽  
Potential Applications

Abstract Ultrawide-angle electromagnetic wave absorbers with excellent mechanical properties are required in many diverse applications such as sensing, and stealth technologies. Here, a novel 3D reconfigurable metamaterial absorber (MMA) consisting of honeycomb and VO2 films is proposed. The proposed MMA exhibits a strong absorptivity above 90% in the widest incident angle up to $$87^\circ $$ 87 ∘ for TM- and TE polarized oblique incidences for THz wave propagating in yoz-plane. Under normal incidence, when VO2 films are in the insulating state, the proposed absorber exhibits high absorptivity in the frequency band of 1–4 THz. By increasing the temperature of the whole structure, the structural transformation of VO2 occurs and turns into the metallic phase. We have shown that under oblique incidence, the ohmic losses of VO2 films especially those parallel to the direction of the incident electric field are the most important absorption principles of the proposed MMA. Due to the ultra wide-angle absorption (angular stability) and mechanical performance, it is expected that the presented MMA may find potential applications, such as camouflage technologies, electromagnetic interference, imaging, and sensing. To the best knowledge of authors, the proposed MMA configuration exhibits the absorptivity in the widest incident angle ever reported.

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