Edge diffraction at a curved screen

1974 ◽  
Vol 10 (10) ◽  
pp. 167 ◽  
Author(s):  
G.L. James
Keyword(s):  
Edge Diffraction

Influence of the Aperture Edge Diffraction Effects on the Mutual Coupling Compensation Technique in Small Planar Antenna Arrays

2011 ◽  
Vol 57 (1) ◽  
pp. 115-120 ◽  
Author(s):  
Mariusz Zamłyński ◽  
Piotr Słobodzian
Keyword(s):  
Antenna Arrays ◽  
Mutual Coupling ◽  
Planar Antenna ◽  
Sidelobe Level ◽  
Edge Diffraction ◽  
Narrow Angle ◽  
Compensation Technique ◽  
Diffraction Effects ◽  
Linear Antenna Arrays

Influence of the Aperture Edge Diffraction Effects on the Mutual Coupling Compensation Technique in Small Planar Antenna Arrays In this paper the quality of a technique to compensate for mutual coupling (and other phenomena) in small linear antenna arrays is investigated. The technique consists in calculation of a coupling matrix, which is than used to determine corrected antenna array excitation coefficients. Although the technique is known for more than 20 years, there is still very little information about how different phenomena existing in a real antenna arrays influence its performance. In this paper two models of antenna arrays are used. In the first model the effect of mutual coupling is separated from the aperture edge diffraction. In the second model antenna both mutual coupling and aperture edge diffraction effects are included. It is shown that mutual coupling itself can be compensated very well and an ultralow sidelobe level (i.e. -50 dB) could be achieved in practice. In the presence of diffraction effects -46.3 dB sidelobe level has been attained, but radiation pattern can be controled only in narrow angle range (i.e. up to ±60°).

scholarly journals Experimental observation of asymmetrical microwave jets and far-field distribution generated by a dual-material system

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
B. Varghese ◽  
O. Shramkova ◽  
P. Minard ◽  
L. Blondé ◽  
V. Drazic ◽  
...  
Keyword(s):  
Near Field ◽  
Microwave Frequency ◽  
Far Field ◽  
Material System ◽  
Field Region ◽  
Edge Diffraction ◽  
Jet Behavior ◽  
Electric Field Profile ◽  
Dual Material ◽  
Plane Wave Diffraction

AbstractIn this paper, we report the experimental and numerical investigation of plane wave diffraction by an all-dielectric dual-material cuboid. Edge diffraction by a cuboid leads to the generation of a narrow, high intensity beam in the near-field region called a photonic jet. We examine the dependence of the jet behavior and orientation on the materials and dimensions of constitutive parts in the microwave frequency domain. The possibility to shift and deviate the resultant microwave jet in the near-field region of such a structure depending on the size of constitutive parts is demonstrated numerically. Experimentally, we observe a shift in the spatial position of the jet. The experimental asymmetric electric field profile observed in the far-field region is attributed to the input of multiple edge waves generated by the dual-material cuboid. The presented results may be scaled at different frequency bands such as optical frequencies for designing nanostructures enabling the focusing and deviation functionality and creation of new optical devices which would satisfy the needs of emerging nanophotonic applications.

Use of RTM full 3D subsurface angle gathers for subsalt velocity update and image optimization: Case study at Shenzi field

Geophysics ◽  
2011 ◽  
Vol 76 (5) ◽  
pp. WB27-WB39 ◽  
Author(s):  
Zheng-Zheng Zhou ◽  
Michael Howard ◽  
Cheryl Mifflin
Keyword(s):  
Model Building ◽  
Transverse Isotropy ◽  
Velocity Model ◽  
Reverse Time ◽  
Reverse Time Migration ◽  
Data Set ◽  
Edge Diffraction ◽  
Time Migration ◽  
Image Optimization ◽  
Free Generation

Various reverse time migration (RTM) angle gather generation techniques have been developed to address poor subsalt data quality and multiarrival induced problems in gathers from Kirchhoff migration. But these techniques introduce new problems, such as inaccuracies in 2D subsurface angle gathers and edge diffraction artifacts in 3D subsurface angle gathers. The unique rich-azimuth data set acquired over the Shenzi field in the Gulf of Mexico enabled the generally artifact-free generation of 3D subsurface angle gathers. Using this data set, we carried out suprasalt tomography and salt model building steps and then produced 3D angle gathers to update the subsalt velocity. We used tilted transverse isotropy RTM with extended image condition to generate full 3D subsurface offset domain common image gathers, which were subsequently converted to 3D angle gathers. The angle gathers were substacked along the subsurface azimuth axis into azimuth sectors. Residual moveout analysis was carried out, and ray-based tomography was used to update velocities. The updated velocity model resulted in improved imaging of the subsalt section. We also applied residual moveout and selective stacking to 3D angle gathers from the final migration to produce an optimized stack image.

Coherence-based edge diffraction sharpening of x-ray images: A simple model

1999 ◽  
Vol 85 (7) ◽  
pp. 3406-3408 ◽  
Author(s):  
G. Margaritondo ◽  
G. Tromba
Keyword(s):  
Simple Model ◽  
X Ray ◽  
Edge Diffraction

Efficient finite-edge diffraction using conservative from-region visibility

2012 ◽  
Vol 73 (3) ◽  
pp. 218-233 ◽  
Author(s):  
Lakulish Antani ◽  
Anish Chandak ◽  
Micah Taylor ◽  
Dinesh Manocha
Keyword(s):  
Edge Diffraction

A Simple Way to Teach Single Slit Diffraction Based on Edge Diffraction

2018 ◽  
Vol 56 (6) ◽  
pp. 380-383 ◽  
Author(s):  
Bettina Teng ◽  
Peter Teng ◽  
Charles H. Hennekens
Keyword(s):  
Edge Diffraction

Edge Diffraction in NURBS-UTD Method

2012 ◽  
Vol 60 (5) ◽  
pp. 2590-2593 ◽  
Author(s):  
Nan Wang ◽  
Hao-Bo Yuan ◽  
Xiao-Jie Dang ◽  
Chang-Hong Liang
Keyword(s):  
Edge Diffraction
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