Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Acoustic vortex field detector based on Fraunhofer diffraction principle

A diffraction principle and Fraunhofer's technology, applied in the field of acoustic vortex field detectors based on the Fraunhofer diffraction principle, can solve the problems of large size and limited application, and achieve a simple method, easy implementation, and easy structure Effect

Inactive Publication Date: 2019-11-22
HEFEI UNIV OF TECH
View PDF5 Cites 3 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Passive methods are mainly divided into three categories: the first category is to use a sound wave propagation distance along the angle The structure of the spiral change, this propagation distance generally refers to the thickness of the structure, the size of this structure is very large, generally on the order of dozens of acoustic wavelengths, which will limit its practical application, especially in the generation of low-frequency acoustic vortexes Applications in Swirling Fields
However, there is no research involving acoustic vortex field detectors

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Acoustic vortex field detector based on Fraunhofer diffraction principle
  • Acoustic vortex field detector based on Fraunhofer diffraction principle
  • Acoustic vortex field detector based on Fraunhofer diffraction principle

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Such as figure 1 As shown in (a), including the substrate with a circular diffraction hole, the number of circular holes in the diffraction hole is N=6, and the incident acoustic vortex wave travels for a certain distance and reaches figure 1 (a) This circular hole array diffraction screen, after passing through the diffraction screen and then propagating for a certain distance, extracts the intensity distribution of the sound field. The theoretical calculation process is as follows:

[0030] The sound field at any point in the acoustic vortex field can be used said, among them is the amplitude and l is the topological charge. The intensity distribution obtained after passing through the multi-hole interference screen is

[0031] (1)

[0032] in, and c are the density and sound velocity of the background medium. For the topological charge of the incident acoustic vortex field is l, the intensity distribution diagram of the interference screen passing throug...

Embodiment 2

[0041] Such as figure 1 As shown in (b), including the substrate whose diffraction hole is an annular triangular hole structure, when the incident sound wave is a vortex wave, the wave field expression on the plane of the annular triangular hole (z=0) is:

[0042] (4)

[0043] where l is the topological charge, is the coordinates in the plane of the triangular hole; is the beam waist size of the vortex sound beam irradiated on the triangular hole.

[0044] When the vortex sound beam is irradiated on the annular triangular hole diffraction screen, the expression of the sound field in the Fraunhofer diffraction area is:

[0045] (5)

[0046] in is the transmittance function.

[0047] for figure 1(b) The simulated intensity distribution diagram obtained by the simulation of this structure is as follows: Figure 4 shown. for Figure 4 , when the frequency is 300kHz, for Figures (a), (c), (d), (h) the outer side length of the annular triangular hole diffraction s...

Embodiment 3

[0049] Such as figure 1 As shown in (c), the substrate including the diffraction hole is an annular ellipse structure, and its theoretical derivation is the same as that of the annular triangular hole diffraction screen. Simulate this structure directly. At a frequency of 300kHz, figure 1 (c) This annular elliptical hole diffraction screen is designed such that the major axis and minor axis of the outer ring are 2.3mm and 1.8mm respectively, and the major axis and minor axis of the inner ring are 1.84mm and 1.44mm respectively. Simulation results such as Figure 5 shown.

[0050] From simulation results Figure 5 It can be seen that when the topological charge of the incident acoustic vortex is 1, there is a dark spot in the center of the intensity distribution, and a singularity in the center of the phase distribution; when the topological charge of the incident acoustic vortex is 2, there are two spots in the center of the intensity distribution. A dark spot with two si...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
Densityaaaaaaaaaa
Radiusaaaaaaaaaa
Login to View More

Abstract

The invention relates to the technical field of acoustic vortex field detectors, in particular to an acoustic vortex field detector based on a Fraunhofer diffraction principle. The acoustic vortex field detector is characterized by comprising a substrate, wherein the acoustic vortex field detector is of a planar structure, diffraction holes are formed in the substrate, topological charges of an incident acoustic vortex field are controlled by means of the sizes and positions of the diffraction holes, acoustic vortex waves carrying different topological charges pass through the diffraction holes based on the Fraunhofer diffraction principle to obtain an uniquely defined far field intensity distribution diagram on a far field observation screen, and the topological charges of the incident acoustic vortex field are obtained through detection according to the comparison between different light intensity diagrams obtained on the far-field observation screen and a theoretical calculation value of the far-field intensity distribution diagram. The acoustic vortex field detector is reasonable in design, the method for measuring the topological charges of the acoustic vortex field by means of the acoustic vortex field detector is simple and easy to implement, and the acoustic vortex field detector can be combined with an existing acoustic vortex field emitter in practical application toachieve acoustic vortex wave communication.

Description

technical field [0001] The invention relates to the technical field of acoustic vortex field detectors, in particular to an acoustic vortex field detector based on the principle of Fraunhofer diffraction. Background technique [0002] Due to the orthogonality between different modes and the infinity of modes, OAM has gradually aroused people's interest in research. This orthogonal characteristic makes the vortex electromagnetic wave have low crosstalk when it is transmitted coaxially, so it can be regarded as another multiplexing method, that is, OAM mode multiplexing. Similarly, the research on the acoustic vortex field carrying orbital angular momentum and having the characteristics of spiral phase distribution is of great value in practice. How to design a simple and effective acoustic vortex field detector has always been a research hotspot in related fields. [0003] At present, the research on acoustic vortex field transmitters has been relatively mature, and can be ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): G01H17/00
CPCG01H17/00
Inventor 郭忠义郭凯周红平李晶晶
Owner HEFEI UNIV OF TECH
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com