System and method for testing absorptivity of flat plate material

Abstract

The invention relates to a system and a method for testing the absorptivity of a flat plate material. The system comprises a control computer, a control cabinet, a rotating motor, a vector network analyzer, a receiving antenna, a transmitting antenna, a first focusing lens, a second focusing lens, a sample clamp, a rotary assembly and a fixed arm. The rotary assembly comprises a rotary arm, a second support and a second rotary shaft, one end of the second rotary shaft is connected with the rotary arm, and the other end is connected with the second support; the sample clamp is fixed on the first support, the first support is rotatably arranged at the top end of the rotary arm, and the sample clamp is used for fixing a flat plate material to be tested; during working, electromagnetic parameters and control parameters are input into the control computer, the vector network analyzer controls the transmitting antenna to emit electromagnetic waves based on the electromagnetic parameters, and the control cabinet sends a rotating instruction to the rotating motor based on the control parameters, so that the rotating motor drives the second rotating shaft to rotate and drives the rotating arm to do circumferential movement. The device can accurately test the wave absorbing performance of the flat plate material.

Description

Technical Field

[0001] The invention relates to the technical field of material performance testing, and in particular to a system and method for testing the absorption rate of a flat material. Background Art

[0002] At present, the evaluation of flat absorbing materials mainly relies on measuring the reflectivity of the materials. On the one hand, the reflectivity test is relatively simple and the technology is relatively mature. On the other hand, during the reflectivity test, the electromagnetic wave is incident from the surface of the material, and the material to be tested needs to be lined with a metal backing plate, so it is assumed that there is no wave transmission.

[0003] However, the traditional reflectivity only considers the backward reflection, and due to the different structures and absorption mechanisms of the absorber materials, the scattered waves do not only exist in the backward direction. Therefore, indirectly evaluating the absorption rate of the material based on the reflectivity cannot accurately reflect the material's absorption performance.

[0004] Therefore, there is an urgent need for a testing system and method for the absorption rate of flat material to solve the above problems. Summary of the invention

[0005] The embodiment of the present invention provides a system and method for testing the absorptivity of a flat plate material, which can accurately test the wave absorbing performance of the flat plate material.

[0006] In a first aspect, an embodiment of the present invention provides a system for testing the absorption rate of a flat material, comprising:

[0007] A control computer, a control cabinet, a rotating motor, a vector network analyzer, a receiving antenna, a transmitting antenna, a first focusing lens, a second focusing lens, a sample fixture, a rotating assembly and a fixed arm; the control computer is respectively connected to the control cabinet and the vector network analyzer for communication, and the vector network analyzer is respectively connected to the receiving antenna and the transmitting antenna for communication;

[0008] The swivel assembly comprises a swivel arm, a second bracket and a second swivel shaft, one end of the second swivel shaft is connected to one end of the bottom side of the swivel arm, and the other end is connected to the second bracket; the sample fixture is fixed on the first bracket, the first bracket is rotatably arranged on the top end of the swivel arm, and the sample fixture is used to fix the flat material to be tested;

[0009] During operation, electromagnetic parameters and control parameters are input into the control computer, the vector network analyzer controls the transmitting antenna to emit electromagnetic waves based on the electromagnetic parameters, and the control cabinet sends a rotation instruction to the rotating motor based on the control parameters, so as to utilize the rotating motor to drive the second rotating shaft to rotate and drive the rotating arm to make circumferential motion.

[0010] In a second aspect, an embodiment of the present invention further provides a method for testing the absorption rate of a flat material, which is applied to the system for testing the absorption rate of a flat material described in any of the above designs, and the method includes:

[0011] Fixing the flat plate material to be tested on the sample fixture;

[0012] Placing the centers of the transmitting antenna, the receiving antenna, the first focusing lens, the second focusing lens and the flat plate material on the same axis;

[0013] The transmitting antenna is used to transmit electromagnetic waves of a preset band, and the electromagnetic waves are sequentially passed through the first focusing lens and the flat material to generate transmission waves, reflection waves and scattered waves respectively; the transmission waves are received by the receiving antenna after passing through the second focusing lens, and the reflection waves are received by the transmitting antenna after passing through the first focusing lens; the vector network analyzer is used to receive the transmission signal of the transmission wave and the reflection signal of the reflection wave to obtain the reflection energy and the transmission energy;

[0014] On the equatorial plane of the flat plate material, the swivel arm is rotated at a preset angle interval to obtain a plurality of angle positions, and at each angle position, the following steps are performed:

[0015] The transmitting antenna is used to transmit the electromagnetic wave of the preset wavelength band, and the electromagnetic wave is sequentially passed through the first focusing lens and the flat material to generate a transmission wave, a reflection wave and a scattered wave respectively; the receiving antenna is used to receive the scattered wave at the angle position, and the vector network analyzer is used to receive the scattered wave signal of the scattered wave until the total scattered energy of the flat material on the equatorial plane is obtained;

[0016] The absorption rate of the flat plate material is determined based on the emission energy, reflection energy, transmission energy and total scattered energy of the electromagnetic wave.

[0017] The embodiment of the present invention provides a system and method for testing the absorptivity of a flat material. In the test system, since the sample fixture can rotate circumferentially along the rotating arm, the transmission and reflection of electromagnetic waves at various incident angles from normal incidence to oblique incidence can be tested. Since the rotating arm can rotate circumferentially along the fixed arm, thereby driving the receiving antenna and the second focusing lens to rotate circumferentially, the receiving antenna can receive transmitted waves and scattered waves at any angle. In other words, the present application can not only test the backscattering of flat materials, but also test the scattered energy in other directions. The test results are closer to the actual situation, so that the wave absorption performance of the flat material can be tested more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a structural schematic diagram of a system for testing the absorption rate of a flat material provided by an embodiment of the present invention.

[0020] Reference numerals:

[0021] 1-control computer; 2-control cabinet; 3-rotating motor; 4-vector network analyzer; 5-receiving antenna; 6-transmitting antenna; 7-first focusing lens; 8-second focusing lens; 9-sample holder; 10-fixed arm; 11-rotating arm; 12-second bracket; 13-second rotating axis; 14-first bracket; 15-third bracket; 16-fourth bracket; 17-fifth bracket; 18-sixth bracket; 19-third rotating axis; 20-fourth rotating axis; 21-fifth rotating axis; 22-sixth rotating axis. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] Please refer to Figure 1 The embodiment of the present invention provides a system for testing the absorption rate of a flat material, comprising:

[0024] A control computer 1, a control cabinet 2, a rotating motor 3, a vector network analyzer 4, a receiving antenna 5, a transmitting antenna 6, a first focusing lens 7, a second focusing lens 8, a sample fixture 9, a rotating assembly and a fixed arm 10; the control computer 1 is respectively connected to the control cabinet 2 and the vector network analyzer 4 for communication, and the vector network analyzer 4 is respectively connected to the receiving antenna 5 and the transmitting antenna 6 for communication;

[0025] The swivel assembly includes a swivel arm 11, a second bracket 12 and a second swivel shaft 13, one end of the second swivel shaft 13 is connected to one end of the bottom side of the swivel arm 11, and the other end is connected to the second bracket 12; the sample fixture 9 is fixed on the first bracket 14, and the first bracket 14 is rotatably arranged on the top of the swivel arm 11, and the sample fixture 9 is used to fix the flat material to be tested;

[0026] During operation, electromagnetic parameters and control parameters are input into the control computer 1, the vector network analyzer 4 controls the transmitting antenna 6 to emit electromagnetic waves based on the electromagnetic parameters, and the control cabinet 2 sends a rotation instruction to the rotating motor 3 based on the control parameters, so as to utilize the rotating motor 3 to drive the second rotating shaft 13 to rotate and drive the rotating arm 11 to make circumferential motion.

[0027] In this embodiment, since the sample holder 9 can rotate circumferentially along the rotating arm 11, the transmission and reflection of electromagnetic waves at various incident angles from normal incidence to oblique incidence can be tested. Since the rotating arm 11 can rotate circumferentially along the fixed arm 10, thereby driving the receiving antenna 5 and the second focusing lens 8 to rotate circumferentially, the receiving antenna 5 can receive transmitted waves and scattered waves at any angle. In other words, the present application can not only test the backscattering of the flat material, but also test the scattered energy in other directions. The test results are closer to the actual situation, so that the wave absorption performance of the flat material can be tested more accurately.

[0028] In addition, the spherical wave of the transmitting antenna 6 can be focused into a focal spot of appropriate size by the first focusing lens 7, which is equivalent to plane wave irradiation, and the focal spot size is not larger than the size of the sample to be measured. The focal spot is irradiated onto the flat material near the focal plane, and the electromagnetic wave is reflected, transmitted and scattered at the interface between the flat material and the free space. In addition, the first focusing lens 7 and the second focusing lens 8 can focus the spherical wave of the transmitting antenna 6 into a focal spot with a diameter of 300 mm and a focal length of 500 mm, which is equivalent to plane wave irradiation, and the size of the flat material to be measured is 500 mm×500 mm.

[0029] It should also be noted that the vector network analyzer 4 is connected to the receiving antenna 5 and the transmitting antenna 6 via RF cables.

[0030] In some embodiments, the transmitting antenna 6, the first focusing lens 7, the receiving antenna 5, and the second focusing lens 8 are fixed to a third bracket 15, a fourth bracket 16, a fifth bracket 17, and a sixth bracket 18, respectively;

[0031] The top ends of the fixed arm 10 and the swivel arm 11 are respectively provided with a first guide rail and a second guide rail along the length direction; the second bracket 12, the third bracket 15 and the fourth bracket 16 can slide along the first guide rail respectively; the fifth bracket 17 and the sixth bracket 18 can slide along the second guide rail respectively.

[0032] In this embodiment, the test range of the test system can be improved by adjusting the positions of and the distances between the transmitting antenna 6, the first focusing lens 7, the receiving antenna 5 and the second focusing lens 8.

[0033] In some embodiments, the third bracket 15 is provided with a third rotating shaft 19, and the transmitting antenna 6 can make circumferential motion driven by the third rotating shaft 19;

[0034] The fourth bracket 16 is provided with a fourth rotating shaft 20, and the first focusing lens 7 can make circumferential motion under the drive of the fourth rotating shaft 20;

[0035] The fifth bracket 17 is provided with a fifth rotating shaft 21, and the receiving antenna 5 can make circumferential motion under the drive of the fifth rotating shaft 21;

[0036] The sixth bracket 18 is provided with a sixth rotating shaft 22 , and the second focusing lens 8 can make circumferential motion driven by the sixth rotating shaft 22 .

[0037] In this embodiment, considering the change of the phase center of the antenna in different frequency bands, the performance of focusing electromagnetic waves and the spatial distribution of the transmitted waves, the distance between the antenna and the focusing lens and the distance between the focusing lens and the flat material to be tested are independently adjustable, so that the application is more flexible. For example, the receiving antenna 5 can realize continuous rotation with an interval of no more than 0.2° between 320° in azimuth through the rotating arm 11. In addition, by adjusting the distance between each focusing lens and the flat material, the energy value at each angle in the full range of angles can be obtained.

[0038] In some embodiments, in order to achieve broadband full-band testing, the transmitting antenna 6 and the receiving antenna 5 are both broadband antennas. Preferably, the antenna coverage range is 4.9 GHz to 7.0 GHz. The first focusing lens 7 and the second focusing lens 8 are both broadband focusing lenses. The corresponding spherical waves are segmented by the focusing lens to be focused into a focal spot with a diameter of about 300 mm, thereby simulating the irradiation of the sample flat material by the plane wave.

[0039] In some embodiments, both the first guide rail and the second guide rail are provided with size scales; and / or,

[0040] The second rotating shaft 13 , the third rotating shaft 19 , the fourth rotating shaft 20 , the fifth rotating shaft 21 and the sixth rotating shaft 22 are all provided with angle scales.

[0041] In this embodiment, the adjustment accuracy can be improved by setting a scale, and the scale accuracy is determined according to user needs, and is preferably not less than 0.2°.

[0042] This embodiment further provides a method for testing the absorption rate of a flat plate material, which is applied to the system for testing the absorption rate of a flat plate material described in any of the above embodiments, and the method includes:

[0043] Fixing the flat plate material to be tested on the sample fixture 9;

[0044] Place the transmitting antenna 6, the receiving antenna 5, the first focusing lens 7, the second focusing lens 8 and the center of the flat plate material on the same axis;

[0045] The transmitting antenna 6 is used to transmit electromagnetic waves of a preset band, and the electromagnetic waves are sequentially passed through the first focusing lens 7 and the flat material to generate transmission waves, reflection waves and scattered waves respectively; the transmission waves are received by the receiving antenna 5 after passing through the second focusing lens 8, and the reflection waves are received by the transmitting antenna 6 after passing through the first focusing lens 7; the vector network analyzer 4 is used to receive the transmission signal of the transmission wave and the reflection signal of the reflection wave to obtain the reflection energy and the transmission energy;

[0046] On the equatorial plane of the flat material, the swivel arm 11 is rotated at a preset angle interval to obtain a plurality of angle positions, and at each angle position, the following operations are performed:

[0047] The transmitting antenna 6 is used to transmit the electromagnetic wave of the preset wavelength band, and the electromagnetic wave generates a transmission wave, a reflection wave and a scattered wave respectively after passing through the first focusing lens 7 and the flat material in sequence; the receiving antenna 5 is used to receive the scattered wave at the angle position, and the vector network analyzer 4 is used to receive the scattered wave signal of the scattered wave, until the total scattered energy of the flat material on the equatorial plane is obtained;

[0048] The absorption rate of the flat plate material is determined based on the emission energy, reflection energy, transmission energy and total scattered energy of the electromagnetic wave.

[0049] In this embodiment, after the scattering parameters are calculated, the dielectric constant, magnetic permeability and reflectivity of the flat material sample can be calculated according to the relationship between the scattering parameters and the electrical parameters.

[0050] In some embodiments, the absorbance of the flat material is determined by the following formula:

[0051] ε=P a / P e

[0052] P a =p e -p r -P t -P s

[0053] Where ε is the absorptivity of the flat material; P a is the absorbed energy of the flat material; P e is the emission energy of electromagnetic waves; P r is the reflected energy of the flat material; P t is the transmitted energy of the flat material; P s is the total scattered energy of the flat plate material on the equatorial plane.

[0054] In some embodiments, the rotating arm 11 rotates under the drive of the rotating motor 3, and the rotating motor 3 sends a synchronous pulse trigger signal to the vector network analyzer 4, so that when the rotating arm 11 moves to a certain angle position, the vector network analyzer 4 is used to collect the scattering signal sent by the receiving antenna 5 to obtain the scattering value at the corresponding angle position.

[0055] In some embodiments, the total scattered energy of the flat plate material on the equatorial plane is calculated by the following formula:

[0056]

[0057] Where P s is the total scattered energy of the flat plate material on the equatorial plane; is the scattered energy of the flat material at angle θ; n is the angular range of the rotation angle of the rotating arm 11.

[0058] In this embodiment, the wave absorption characteristics of the material are usually indirectly reflected according to the reflectivity of the material, because it is difficult to measure the scattering characteristics of the material in the whole space. However, for flat-type materials, the scattering direction is mostly perpendicular to the equatorial plane of the material, so the scattering measured on this series of equatorial parallel planes can reflect the absorption characteristics of the material to a certain extent.

[0059] In some embodiments, the scattered energy can be measured according to the method of wave transmission energy, and the spatial scattered energy can refer to the test method of wave transmission rate. The wave transmission rate is defined as: under the conditions of given wavelength and polarization, electromagnetic waves are emitted from a horn antenna with the same power density and arrive at the receiving horn antenna in the same straight line direction through the same path. A plate of the material to be tested is placed in the middle of the two horn antennas. The ratio of the wave transmission power at this time to the received power when no material plate is placed is the wave transmission rate of the material plate. The specific calculation process of the wave transmission rate is as follows:

[0060] The frequency response calibration of the test system is performed when the sample fixture 9 is not provided with the flat plate material to be tested, and the received power P0(f) of the test system varying with the frequency is obtained;

[0061] When the sample fixture 9 is equipped with the flat plate material to be tested, the frequency response of the test system is measured to obtain the wave transmission power P1(f) of the test system that varies with frequency;

[0062] The ratio of the transmitted power to the received power is determined as the transmittance T(f) of the flat plate material to be tested:

[0063] T(f)=P1(f) / P0(f)×100.

[0064] It should be noted that the test method for the absorption rate of a flat plate material provided in this embodiment and the test system for the absorption rate of a flat plate material provided in the above embodiment are based on the same inventive concept, and therefore both have the same beneficial effects, which will not be described in detail herein.

[0065] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical factors in the process, method, article or device including the elements.

[0066] A person of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk, etc., various media that can store program codes.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for testing the absorption rate of a flat material, characterized in that: include: A control computer (1), a control cabinet (2), a rotating motor (3), a vector network analyzer (4), a receiving antenna (5), a transmitting antenna (6), a first focusing lens (7), a second focusing lens (8), a sample holder (9), a rotating assembly and a fixed arm (10); the control computer (1) is respectively connected to the control cabinet (2) and the vector network analyzer (4), and the vector network analyzer (4) is respectively connected to the receiving antenna (5) and the transmitting antenna (6); The swivel assembly comprises a swivel arm (11), a second bracket (12) and a second swivel shaft (13), one end of the second swivel shaft (13) is connected to one end of the bottom side of the swivel arm (11), and the other end is connected to the second bracket (12); the sample fixture (9) is fixed on the first bracket (14), the first bracket (14) is rotatably arranged on the top end of the swivel arm (11), and the sample fixture (9) is used to fix the flat plate material to be tested; During operation, electromagnetic parameters and control parameters are input into the control computer (1), the vector network analyzer (4) controls the transmitting antenna (6) to emit electromagnetic waves based on the electromagnetic parameters, and the control cabinet (2) sends a rotation instruction to the rotating motor (3) based on the control parameters, so as to utilize the rotating motor (3) to drive the second rotating shaft (13) to rotate and drive the rotating arm (11) to perform circumferential motion.

2. The system according to claim 1, characterized in that The transmitting antenna (6), the first focusing lens (7), the receiving antenna (5), and the second focusing lens (8) are respectively fixed on a third bracket (15), a fourth bracket (16), a fifth bracket (17), and a sixth bracket (18); The top ends of the fixed arm (10) and the swivel arm (11) are respectively provided with a first guide rail and a second guide rail which are continuous in the length direction; the second bracket (12), the third bracket (15) and the fourth bracket (16) can slide along the first guide rail respectively; the fifth bracket (17) and the sixth bracket (18) can slide along the second guide rail respectively.

3. The system according to claim 2, characterized in that The third bracket (15) is provided with a third rotating shaft (19), and the transmitting antenna (6) can move in a circumferential direction under the drive of the third rotating shaft (19); The fourth bracket (16) is provided with a fourth rotating shaft (20), and the first focusing lens (7) can move in a circumferential direction under the drive of the fourth rotating shaft (20); The fifth bracket (17) is provided with a fifth rotating shaft (21), and the receiving antenna (5) can move in a circumferential direction under the drive of the fifth rotating shaft (21); The sixth bracket (18) is provided with a sixth rotating shaft (22), and the second focusing lens (8) can move in a circumferential direction under the drive of the sixth rotating shaft (22).

4. The system according to claim 1, characterized in that The transmitting antenna (6) and the receiving antenna (5) are both broadband antennas.

5. The system according to claim 1, characterized in that The first focusing lens (7) and the second focusing lens (8) are both broadband focusing lenses.

6. The system according to claim 3, characterized in that The first guide rail and the second guide rail are both provided with size scales; and / or, The second rotating shaft (13), the third rotating shaft (19), the fourth rotating shaft (20), the fifth rotating shaft (21) and the sixth rotating shaft (22) are all provided with angle scales.

7. A method for testing the absorption rate of a flat material, characterized in that: A system for testing the absorption rate of a flat material according to any one of claims 1 to 6, the method comprising: Fixing the flat plate material to be tested on the sample fixture (9); Placing the transmitting antenna (6), the receiving antenna (5), the first focusing lens (7), the second focusing lens (8) and the center of the flat plate material on the same axis; The transmitting antenna (6) is used to transmit electromagnetic waves of a preset wavelength band, and the electromagnetic waves are sequentially passed through the first focusing lens (7) and the flat material to generate transmission waves, reflection waves and scattered waves respectively; the transmission waves are received by the receiving antenna (5) after passing through the second focusing lens (8), and the reflection waves are received by the transmitting antenna (6) after passing through the first focusing lens (7); the transmission signal of the transmission wave and the reflection signal of the reflection wave are received by the vector network analyzer (4) to obtain reflection energy and transmission energy; On the equatorial plane of the flat plate material, the rotating arm (11) is rotated at a preset angle interval to obtain a plurality of angle positions, and at each angle position, the following steps are performed: The transmitting antenna (6) is used to transmit electromagnetic waves of the preset wavelength band, and the electromagnetic waves respectively generate transmission waves, reflection waves and scattered waves after passing through the first focusing lens (7) and the flat plate material in sequence; the scattered waves at the angle position are received by the receiving antenna (5), and the scattered wave signals of the scattered waves are received by the vector network analyzer (4), until the total scattered energy of the flat plate material on the equatorial plane is obtained; The absorption rate of the flat plate material is determined based on the emission energy, reflection energy, transmission energy and total scattered energy of the electromagnetic wave.

8. The method according to claim 7, characterized in that The absorptivity of the flat material is determined by the following formula: e=P a / P e P a =P e -P r -P t -P s Where ε is the absorptivity of the flat material; P a is the absorbed energy of the flat material; P e is the emission energy of electromagnetic waves; P r is the reflected energy of the flat material; P t is the transmitted energy of the flat material; P s is the total scattered energy of the flat plate material on the equatorial plane.

9. The method according to claim 7, characterized in that: The swivel arm (11) performs swivel motion under the drive of the rotary motor (3), and the rotary motor (3) sends a synchronous pulse trigger signal to the vector network analyzer (4), so that when the swivel arm (11) moves to a certain angle position, the vector network analyzer (4) collects the scattered signal sent by the receiving antenna (5) to obtain the scattering value at the corresponding angle position.

10. The method according to claim 7, characterized in that The total scattered energy of the flat plate material on the equatorial plane is calculated by the following formula: Where P s is the total scattered energy of the flat plate material on the equatorial plane; is the scattered energy of the flat plate material at angle θ; and n is the angular range of the rotation angle of the rotating arm (11).

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