scholarly journals Hybrid holographic Maxwellian near-eye display based on spherical wave and plane wave reconstruction for augmented reality display

2021 ◽  
Vol 29 (4) ◽  
pp. 4927
Author(s):  
Zi Wang ◽  
Xu Zhang ◽  
Guoqiang Lv ◽  
Qibin Feng ◽  
Hai Ming ◽  
...  
Keyword(s):  
Augmented Reality ◽  
Plane Wave ◽  
Spherical Wave

LOW-FREQUENCY ACOUSTIC SCATTERING BY AN INHOMOGENEOUS MEDIUM

2005 ◽  
Vol 15 (10) ◽  
pp. 1459-1468 ◽  
Author(s):  
GEORGE VENKOV
Keyword(s):  
Refractive Index ◽  
Plane Wave ◽  
Inhomogeneous Medium ◽  
Acoustic Waves ◽  
Spherical Wave ◽  
Low Frequency ◽  
Far Field ◽  
Scattering Medium ◽  
Wave Incidence ◽  
Plane Wave Incidence

This paper deals with the scattering of time-harmonic acoustic waves by inhomogeneous medium. We study the problem to recover the near and the far field using a priori information about the refractive index and the support of inhomogeneity. The incident spherical wave is modified in such a way as to recover the plane wave incidence when the source point approaches infinity. Applying the low-frequency expansions, the scattering medium problem is reduced to a sequence of potential problems for the approximation coefficients in the presence of a monopole singularity located at the source of incidence. Complete expansions for the integral representation formula in the near field as well as for the scattering amplitude in the far field are provided. The method is applied to the case of a spherical region of inhomogeneity and a radial dependent refractive index. As the point singularity tends to infinity, the relative results recover the scattering medium problem for plane wave incidence.

Properties of the transformation from the spherical wave expansion to the plane wave expansion

Radio Science ◽  
2008 ◽  
Vol 43 (1) ◽  
pp. n/a-n/a ◽  
Author(s):  
Cecilia Cappellin ◽  
Olav Breinbjerg ◽  
Aksel Frandsen
Keyword(s):  
Plane Wave ◽  
Spherical Wave ◽  
Plane Wave Expansion ◽  
Wave Expansion ◽  
Spherical Wave Expansion

X-ray Fourier transform holography by amplitude-division-type Fresnel zone plate interferometer

2018 ◽  
Vol 25 (1) ◽  
pp. 241-247 ◽  
Author(s):  
Minas Balyan ◽  
Levon Haroutunyan
Keyword(s):  
Fourier Transform ◽  
Plane Wave ◽  
Fresnel Zone ◽  
Spherical Wave ◽  
Zone Plate ◽  
Fresnel Zone Plate ◽  
Focal Distance ◽  
X Ray ◽  
Wave Forms ◽  
The Fourier Transform

A two-block X-ray Fresnel zone plate system forms two-beams – a plane wave and a spherical wave – which interfere at the focal distance of the virtual source of the spherical wave. An object placed in the path of the plane wave forms an object wave and the spherical wave is the reference wave. The recorded intensity distribution is the Fourier transform hologram of the object. Analytical and numerical calculations show the possibilities of this scheme to record the hologram and reconstruct the object image. Examples of recording holograms of a one-dimensional cosine-like grating and a two-dimensional grid object as well as reconstruction of the images are considered.

Amplitude and phase versus angle for elastic wide-angle reflections in the τ‐p domain

Geophysics ◽  
2015 ◽  
Vol 80 (1) ◽  
pp. N1-N9 ◽  
Author(s):  
Xinfa Zhu ◽  
George A. McMechan
Keyword(s):  
Plane Wave ◽  
Incident Angle ◽  
Plane Waves ◽  
Spherical Wave ◽  
Reflection Coefficients ◽  
Phase Versus ◽  
Angle Data ◽  
Wave Effects ◽  
Phase Variations ◽  
Time Offset

Near- and postcritical spherical-wave reflections contain amplitude and phase variations with incident angle that are not predicted by plane-wave solutions. However, if a spherical wavefield is decomposed into plane waves by a time-intercept-slowness ([Formula: see text]) transform, then plane-wave reflection coefficients (the Zoeppritz) can be used as the basis of amplitude/phase versus angle analysis. The spherical-wave effects on reflection coefficients near the critical angle (in the time-offset domain) were decomposed by [Formula: see text] transformation into plane waves. Kinematic ray tracing linked the reflection angle at the target reflector and the apparent slowness at the surface receiver, which enabled extracting the amplitude/phase versus angle data at the reflector from the surface [Formula: see text] data. The most reliable inversion results were obtained by combining the extracted amplitudes and phases in a composite inversion for the elastic parameters below the target reflector.

scholarly journals Experimental verification of spherical-wave effect on the AVO response and implications for three-term inversion

Geophysics ◽  
2008 ◽  
Vol 73 (2) ◽  
pp. C7-C12 ◽  
Author(s):  
Mohammed Alhussain ◽  
Boris Gurevich ◽  
Milovan Urosevic
Keyword(s):  
Plane Wave ◽  
Spherical Wave ◽  
Least Square ◽  
Elastic Parameters ◽  
Least Square Fitting ◽  
Full Wave ◽  
Alternative Approach ◽  
Class 1 ◽  
Elastic Inversion ◽  
Two Parameter

Spherical-wave offset-dependent reflectivity is investigated by measuring ultrasonic reflection amplitudes from a water/Plexiglas interface. The experimental results show substantial deviation of the measured amplitudes from the plane-wave reflection coefficients at large angles. However, full-wave numerical simulations of the point source reflection response using the reflectivity algorithm show excellent agreement with the measurements, demonstrating that the deviation from the plane-wave response is caused by the wavefront curvature. To analyze the effect of wavefront curvature on elastic inversion, we simulate the spherical-wave reflectivity at different frequencies and invert for elastic parameters by least-square fitting of the plane-wave (Zoeppritz) solution. The results show that the two-parameter inversion based on the intercept and gradient is robust, although estimation of three parameters ([Formula: see text], [Formula: see text], and density) that use the curvature of the offset variation with angle (AVA) response is prone to substantial frequency-dependent errors. We propose an alternative approach to parameter estimation, one that uses critical angles estimated from AVA curves (instead of the AVA curvature). This approach shows a significant improvement in the estimation of elastic parameters, and it could be applied to class 1 AVO responses.

scholarly journals Gain Enhancement of Horn Antenna Using Meta Surface Lens

2018 ◽  
Vol 7 (4) ◽  
pp. 27-33 ◽  
Author(s):  
R. Manikandan ◽  
P. H. Rao ◽  
P. K. Jawahar
Keyword(s):  
Plane Wave ◽  
Spherical Wave ◽  
Three Dimensional ◽  
Beam Width ◽  
Horn Antenna ◽  
Beam Shaping ◽  
Radiation Characteristics ◽  
Gain Enhancement ◽  
Wide Range ◽  
Operating Bandwidth

Three dimensional meta surface lens is proposed to improve the gain and beam shaping of horn antenna. Hence an array of SRR as a meta surface lens has been designed, fabricated and investigated. This meta surface lens can be used to convert the spherical wave to plane wave for a wide range of frequency. It is proved by permeability and permittivity of meta surface. In this work the operating bandwidth of the proposed antenna is in the range of 9GHz to 11GHz for satellite application. The radiation pattern of E and H plane is sharpened in this work. The antenna 3dB beam width, and front to back ratio were 9.2, 28dB at 10GHz. The radiation characteristics of horn antenna with meta surface have been studied numerically and confirmed experimentally, showing an average gain improvement of ~3dB with respect to horn antenna without meta surface lens.

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