Quiet Zone Quality of a Plane Wave Generator inside an Over-Moded Waveguide Chamber Emulating a Variable Angle of Incidence

This study derives a preconditioned stochastic conjugate gradient (CG) method that combines stochastic optimization with singular spectrum analysis (SSA) denoising to improve the efficiency and image quality of plane-wave least-squares reverse time migration (PLSRTM). This method reduces the computational costs of PLSRTM by applying a controlled group-sampling method to a sufficiently large number of plane-wave sections and accelerates the convergence using a hybrid of stochastic descent (SD) iteration and CG iteration. However, the group sampling also produces aliasing artifacts in the migration results. We use SSA denoising as a preconditioner to remove the artifacts. Moreover, we implement the preconditioning on the take-off angle-domain common-image gathers (CIGs) for better results. We conduct numerical tests using the Marmousi model and Sigsbee2A salt model and compare the results of this method with those of the SD method and the CG method. The results demonstrate that our method efficiently eliminates the artifacts and produces high-quality images and CIGs.

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Variable Angle of Incidence Spectroscopic Ellipsometric Measurement of the Franz-Keloysh Effect in Modfet Structures

MRS Proceedings ◽

10.1557/proc-77-761 ◽

1986 ◽

Vol 77 ◽

Cited By ~ 5

Author(s):

P. G. Snyder ◽

J. E. Oh ◽

J. A. Woollam

Keyword(s):

Electric Field ◽

Bandgap Energy ◽

Model Parameters ◽

Angle Of Incidence ◽

Internal Electric Field ◽

Ellipsometric Measurement ◽

Band Bending ◽

Variable Angle ◽

Two Samples ◽

Franz Keldysh Effect

ABSTRACTIt has been shown recently that variable angle of incidence spectroscopie ellipsometry (VASE) is a sensitive technique for determining semiconductor multilayer model parameters, e.g. layer thicknesses and ternary compositions. In this paper we show that VASE is, in addition, sensitive to the Franz-Keldysh effect induced by band bending in the barrier layer of a GaAs-AlGaAs-GaAs (MODFET) structure. VASE measurements differ from electro-reflectance and photoreflectance, in that the internal heterojunction region electric field is directly probed, without the application of a modulating field. The Franz-Keldysh effect appears in the VASE spectra near the AlGaAs bandgap energy. Data for two samples, with different doping profiles, are quantitatively modeled to determine the internal electric field amplitudes.

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A New Test Method for 5G Massive MIMO Devices: Plane Wave Generator with 36 Planar Array Antenna

Advances in Wireless Communications and Applications - Smart Innovation, Systems and Technologies ◽

10.1007/978-981-15-5879-5_6 ◽

2020 ◽

pp. 39-45

Author(s):

Yu Zhang ◽

Xiang Wu ◽

Xiang Zhang ◽

Yuxin Ren ◽

Chong Pan ◽

...

Keyword(s):

Plane Wave ◽

Massive Mimo ◽

Test Method ◽

Array Antenna ◽

Wave Generator ◽

Planar Array

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Low Scattering Plane Wave Generator Design Using a Novel Non-Coplanar Structure for Near-Field Over-the-Air Testing

IEEE Access ◽

10.1109/access.2020.3039367 ◽

2020 ◽

Vol 8 ◽

pp. 211348-211357

Author(s):

Zhaolong Qiao ◽

Zhengpeng Wang ◽

Wei Fan ◽

Xue Zhang ◽

Steven Gao ◽

...

Keyword(s):

Plane Wave ◽

Near Field ◽

Wave Generator ◽

Generator Design

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Design and Simulation of a 28 GHz Plane Wave Generator for NR Measurements

2020 14th European Conference on Antennas and Propagation (EuCAP) ◽

10.23919/eucap48036.2020.9135243 ◽

2020 ◽

Author(s):

Sara Catteau ◽

Marianna Ivashina ◽

Robert Rehammar

Keyword(s):

Plane Wave ◽

Wave Generator

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Texture Analysis with Area Detectors

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.105.71 ◽

2005 ◽

Vol 105 ◽

pp. 71-76 ◽

Cited By ~ 9

Author(s):

Kurt Helming ◽

Uwe Preckwinkel

Keyword(s):

Texture Analysis ◽

Pole Figure ◽

Data Sets ◽

Angle Of Incidence ◽

Surface Layers ◽

Area Detector ◽

Texture Information ◽

Pole Figures ◽

Information Depth

Starting from simple geometric considerations concerning directions and orientations, intelligent strategies for pole figure measurements were developed for the area detector. The amount and quality of texture information contained in measured or available data sets can be directly controlled. The texture approximation is done by the component method. The method does not have any restrictions concerning the grids of sample directions in the pole figures. An almost constant information depth can be obtained at a low angle of incidence of the primary beam for the study of thin surface layers.

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