Near- and far-field beam forming using a linear array in deep and shallow water

2014 ◽  
Vol 135 (4) ◽  
pp. 2393-2393
Author(s):  
Richard L. Culver ◽  
Brian E. Fowler ◽  
D. Chris Barber
Keyword(s):  
Shallow Water ◽  
Linear Array ◽  
Beam Forming ◽  
Far Field

Comparison between DOA Estimation Subspace methods for incoherent and coherent signals

2015 ◽  
Vol 1 ◽  
pp. 18
Author(s):  
Ahmed Abdalla ◽  
Suhad Mohammed ◽  
Tang Bin ◽  
Jumma Mary Atieno ◽  
Abdelazeim Abdalla
Keyword(s):  
Linear Array ◽  
Doa Estimation ◽  
Far Field ◽  
Matlab Simulation ◽  
Subspace Methods ◽  
Coherent Signals ◽  
Uniform Linear Array ◽  
Pros And Cons ◽  
Basic Concepts ◽  
And Performance

This paper considers the problem of estimating the direction of arrival (DOA) for the both incoherent and coherent signals from narrowband sources, located in the far field in the case of uniform linear array sensors. Three different methods are analyzed. Specifically, these methods are Music, Root-Music and ESPRIT. The pros and cons of these methods are identified and compared in light of different viewpoints. The performance of the three methods is evaluated, analytically, when possible, and by Matlab simulation. This paper can be a roadmap for beginners in understanding the basic concepts of DOA estimation issues, properties and performance.

Localisation of mixed near‐field and far‐field sources using the largest aperture sparse linear array

2018 ◽  
Vol 12 (2) ◽  
pp. 155-162 ◽  
Author(s):  
Ali Akbar Ebrahimi ◽  
Hamid Reza Abutalebi ◽  
Mahmood Karimi
Keyword(s):  
Linear Array ◽  
Near Field ◽  
Far Field ◽  
Sparse Linear Array

scholarly journals Far-Field Characteristics of Linear Water Waves Generated by a Submerged Landslide over a Flat Seabed

2020 ◽  
Vol 8 (3) ◽  
pp. 196
Author(s):  
Haixiao Jing ◽  
Yanyan Gao ◽  
Changgen Liu ◽  
Jingming Hou
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Water Waves ◽  
Wave Model ◽  
Linear Wave ◽  
Far Field ◽  
Constant Depth ◽  
Low Froude Number ◽  
Dispersive Model ◽  
Wave Models

Understanding the propagation of landslide-generated water waves is of great help against tsunami hazards. In order to investigate the effects of landslide shapes on the far-field leading wave generated by a submerged landslide at a constant depth, three linear wave models with different degrees of dispersive properties are employed in this study. The linear fully dispersive model is then validated by comparing the results against the experimental data available for landslides with a low Froude number. Three simplified shapes of landslides with the same volume, which are unnatural for a body of incoherent material, are used to investigate the effects of landslide shapes on the far-field properties of the generated leading wave over a flat seabed. The results show that the far-field leading crest over a constant depth is independent of the exact landslide shape and is invalid at a shallow water depth. Therefore, the most popular non-dispersive model (also called the shallow water wave model) cannot be used to reproduce the phenomenon. The weakly dispersive wave model can predict this phenomenon well. If only the leading wave is considered, this model is accurate up to at least μ = h0/Lc = 0.6, where h0 is the water depth and Lc denotes the characteristic length of the landslide.

scholarly journals A performance predictor of beamforming versus time-reversal based far-field wireless power transfer from linear array

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hong Soo Park ◽  
Sun K. Hong
Keyword(s):  
Time Reversal ◽  
Power Transmission ◽  
Linear Array ◽  
Wireless Power Transfer ◽  
Far Field ◽  
Power Transfer ◽  
Wireless Power ◽  
Dynamic Propagation ◽  
Received Power ◽  
Indoor Scenarios

AbstractFor far-field wireless power transfer (WPT) in a complex propagation environment, a time-reversal (TR) based WPT that can overcome the drawbacks of conventional beamforming (BF) by taking advantage of multipath has been recently proposed. However, due to the WPT performance of BF and TR depending on the complexity of the propagation environment, the performance prediction between BF versus TR would be required. We present a detailed and generalized analysis of the recently proposed performance metric referred to as the peak received power ratio (PRPR) for linear array-based WPT. Here, the effectiveness of PRPR is verified via measurement for free space and indoor scenarios. The results demonstrate that PRPR is directly related to the complexity of the propagation environment and the corresponding power transmission capability of BF and TR. That is, the higher the complexity, the greater the value of PRPR and TR outperforms BF with higher peak power given the same average transmit power and vice versa. The mode decision between BF and TR based on PRPR potentially promises efficient far-field WPT even in a dynamic propagation environment.

scholarly journals A Novel Algorithm to Estimate Closely Spaced Source DOA

2017 ◽  
Vol 7 (4) ◽  
pp. 2109 ◽  
Author(s):  
Sidi Mohamed Hadj Irid ◽  
Samir Kameche ◽  
Said Assous
Keyword(s):  
Classical Music ◽  
Linear Array ◽  
Doa Estimation ◽  
Spatial Sampling ◽  
Signal Classification ◽  
Far Field ◽  
Uniform Linear Array ◽  
Resolution Method ◽  
Multiple Signal Classification ◽  
High Resolution Method

<p>In order to improve resolution and direction of arrival (DOA) estimation of two closely spaced sources, in context of array processing, a new algorithm is presented. However, the proposed algorithm combines both spatial sampling technic to widen the resolution and a high resolution method which is the Multiple Signal Classification (MUSIC) to estimate the DOA of two closely spaced sources impinging on the far-field of Uniform Linear Array (ULA). Simulations examples are discussed to demonstrate the performance and the effectiveness of the proposed approach (referred as Spatial sampling MUSIC SS-MUSIC) compared to the classical MUSIC method when it’s used alone in this context.</p>

A Combined Finite Element Method with Normal Mode for the Elastic Structural Acoustic Radiation in Shallow Water

2020 ◽  
Vol 28 (04) ◽  
pp. 2050004
Author(s):  
Buchao An ◽  
Chao Zhang ◽  
Dejiang Shang ◽  
Yan Xiao ◽  
Imran Ullah Khan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Shallow Water ◽  
Normal Mode ◽  
Acoustic Field ◽  
Acoustic Radiation ◽  
Three Dimensional ◽  
Far Field ◽  
Azimuthal Direction ◽  
Element Method

A combined Finite Element Method with Normal Mode (FEM-NM) is proposed for calculation of the acoustic field radiated by a three-dimensional structural source in shallow water. The FEM is used to calculate the near range acoustic field, then the modes expansion at the vertical and azimuthal direction is performed at a certain coupling range. Hence, the true three-dimensional acoustic field at any range is obtained rapidly by the NM theory. The numerical examples show the efficiency and accuracy of this method. The coupling range and the truncation of the vertical modes hardly affect the far field results.

scholarly journals "IMPROVEMENT OF FAR FIELD RADIATION PATTERN OF LINEAR ARRAY ANTENNA USING GENETIC ALGORITHM"

2010 ◽  
Vol 01 (01) ◽  
pp. 23-31 ◽  
Author(s):  
Sudipta Das ◽  
◽  
Somen Bhattacharjee ◽  
Durbadal Mandal ◽  
◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Radiation Pattern ◽  
Linear Array ◽  
Array Antenna ◽  
Far Field ◽  
Field Radiation
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