Wavelet denoising for plane wave DOA estimation by MUSIC

In this paper, we present a metasurface-based Direction of Arrival (DoA) estimation method that exploits the properties of space-time modulated reflecting metasurfaces to estimate in real-time the impinging angle of an illuminating monochromatic plane wave. The approach makes use of the amplitude unbalance of the received fields at broadside at the frequencies of the two first-order harmonics generated by the interaction between the incident plane wave and the modulated metasurface. Here, we first describe analytically how to generate the desired higher-order harmonics in the reflected spectrum and how to realize the breaking of the spatial symmetry of each order harmonic scattering pattern. Then, the one dimensional (1D) omnidirectional incident angle can be analytically computed using +1st and -1st order harmonics. The approach is also extended to 2D DoA estimation by using two orthogonally arranged 1D DoA modulation arrays. The accuracy of 1D DoA estimation is verified through full-wave numerical simulations. Compared to conventional DoA estimation methods, the proposed approach simplifies the computation and hardware complexity, ensuring at the same time estimation accuracy. The proposed method may have potential applications in wireless communications, target recognition, and identification.

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Frequency-Diverse Computational Direction of Arrival Estimation Technique

Scientific Reports ◽

10.1038/s41598-019-53363-3 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 3

Author(s):

Okan Yurduseven ◽

Muhammad Ali Babar Abbasi ◽

Thomas Fromenteze ◽

Vincent Fusco

Keyword(s):

Plane Wave ◽

Spatial Information ◽

Single Channel ◽

Plane Waves ◽

Direction Of Arrival ◽

Doa Estimation ◽

Estimation Technique ◽

Frequency Diversity ◽

Millimetre Wave ◽

Single Antenna

Abstract We present a frequency-diverse based direction of arrival (DoA) estimation technique for millimetre-wave (mmW) 5G channel sounding. Frequency-diversity enables the creation of spatially incoherent radiation masks to encode the plane-wave signals incident on the radar aperture using a single antenna. Leveraging the frequency-diversity concept, spatial information of the plane-wave projections on the radar aperture is retrieved, resulting in high-fidelity DoA estimations by means of a simple Fourier transform operation applied to the retrieved plane-wave projection patterns. It is demonstrated that using the frequency-diversity concept, DoA estimation can be achieved through a simple frequency sweep, compressing the incoming plane-waves into a single channel through the transfer function of the radar aperture. This results in a significant simplification in the system hardware, requiring only a single antenna to achieve DoA estimation. It is also shown that the proposed technique can simultaneously detect the DoA information for multiple sources with a diffraction limited resolution.

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Accurate Direction-of-Arrival Estimation Method based on Space-Time Modulated Metasurface

10.36227/techrxiv.17698181.v1 ◽

2022 ◽

Author(s):

Mengmeng Li

Keyword(s):

Plane Wave ◽

Incident Angle ◽

Estimation Method ◽

Time Estimation ◽

Direction Of Arrival ◽

Doa Estimation ◽

Space Time ◽

Estimation Methods ◽

Estimation Accuracy ◽

Hardware Complexity

In this paper, we present a metasurface-based Direction of Arrival (DoA) estimation method that exploits the properties of space-time modulated reflecting metasurfaces to estimate in real-time the impinging angle of an illuminating monochromatic plane wave. The approach makes use of the amplitude unbalance of the received fields at broadside at the frequencies of the two first-order harmonics generated by the interaction between the incident plane wave and the modulated metasurface. Here, we first describe analytically how to generate the desired higher-order harmonics in the reflected spectrum and how to realize the breaking of the spatial symmetry of each order harmonic scattering pattern. Then, the one dimensional (1D) omnidirectional incident angle can be analytically computed using +1st and -1st order harmonics. The approach is also extended to 2D DoA estimation by using two orthogonally arranged 1D DoA modulation arrays. The accuracy of 1D DoA estimation is verified through full-wave numerical simulations. Compared to conventional DoA estimation methods, the proposed approach simplifies the computation and hardware complexity, ensuring at the same time estimation accuracy. The proposed method may have potential applications in wireless communications, target recognition, and identification.

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Fast DOA estimation using wavelet denoising on MIMO fading channel

The International journal of Multimedia & Its Applications ◽

10.5121/ijma.2011.3414 ◽

2011 ◽

Vol 3 (4) ◽

pp. 171-182

Author(s):

Meenakshi ◽

Punitham ◽

Kayalvizhi ◽

Asha

Keyword(s):

Fading Channel ◽

Doa Estimation ◽

Wavelet Denoising

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Theory and Errors in Stereo Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101426 ◽

1968 ◽

Vol 26 ◽

pp. 336-337

Author(s):

J. M. Pankratz

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Plane Wave ◽

Focal Length ◽

Foil Thickness ◽

Points Of Interest ◽

Transmission Electron ◽

Vertical Spacing ◽

Illuminating System

It is often desirable in transmission electron microscopy to know the vertical spacing of points of interest within a specimen. However, in order to measure a stereo effect, one must have two pictures of the same area taken from different angles, and one must have also a formula for converting measured differences between corresponding points (parallax) into a height differential.Assume (a) that the impinging beam of electrons can be considered as a plane wave and (b) that the magnification is the same at the top and bottom of the specimen. The first assumption is good when the illuminating system is overfocused. The second assumption (the so-called “perspective error”) is good when the focal length is large (3 x 107Å) in relation to foil thickness (∼103 Å).

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