Substance characteristic testing device and method based on terahertz waves

Abstract

The invention discloses a terahertz wave-based material characteristic testing device and method. The terahertz wave-based material characteristic testing device comprises a transmitting antenna, a base assembly and a receiving antenna, the transmitting antenna and the receiving antenna are in transmission connection with the two ends of the base assembly through threads respectively. The axes of the transmitting antenna and the receiving antenna coincide, and the transmitting antenna and the receiving antenna can move along the axes; the horn mouth surface of the transmitting antenna and the horn mouth surface of the receiving antenna are oppositely arranged, and when the transmitting antenna and the receiving antenna move to the bottom along the axis, the horn mouth surface of the transmitting antenna and the horn mouth surface of the receiving antenna are seamlessly attached; a to-be-tested substance is placed on the base assembly, and the to-be-tested substance is clamped by the transmitting antenna and the receiving antenna during testing. The method does not need to depend on an S parameter test module for positioning, does not need to cooperate with auxiliary equipment, reduces the cost of equipment purchase, simplifies the operation process, avoids the complex adjustment process, and improves the detection efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of material characteristic detection, and in particular to a material characteristic testing device and method based on terahertz waves. Background Art

[0002] Most substances in nature have obvious responses in the terahertz band, such as the vibration and rotation energy levels of many biological macromolecules, and the phonon vibration energy levels of semiconductors and superconducting materials. Most non-polar materials have no obvious absorption in the terahertz band, and terahertz radiation has a very strong penetrating ability for these materials. The molecular vibration spectra of many large materials have many characteristic absorption peaks in the terahertz band, and terahertz waves have a certain penetrating ability. Unlike X-rays and other bands, the photon energy in the terahertz band is very low. The energy of a single photon of 1THz electromagnetic radiation is only 4.1meV, which is less than one millionth of the energy of a single photon of X-ray electromagnetic radiation. Therefore, it will not cause damage to the material, thereby achieving the purpose of non-destructive testing of the material, which makes the terahertz band have a basis for wide application in the field of material detection and analysis.

[0003] At present, the frequency band used for terahertz spectrum feature detection of materials is between 110GHz and 1100GHz. There are usually two methods: the first is to fix the terahertz corrugated horn antenna directly on the port of the test instrument, and move the test instrument to clamp the material under test on the antenna horn mouth, and then perform relevant operations; the second is to use a clamp to fix one terahertz corrugated horn antenna and place the other terahertz corrugated horn antenna on a mobile platform, and use a motion mechanism to make the distance between the terahertz corrugated horn antennas adjustable to complete the test.

[0004] The first method mentioned above usually fixes the terahertz corrugated horn antenna directly on the port of the S parameter test module, so the terahertz corrugated horn antennas at the transmitting end and the receiving end are physically separated. Whether they are aligned is determined by the S parameter test module, and the port height and horizontal angle of the S parameter test module are inaccurate and vary within a large range. Therefore, before the test, the S parameter test module needs to be leveled and straightened in three-dimensional space so that the axes of the two terahertz corrugated horn antennas coincide, and the distance deviation between them cannot exceed 0.1mm, and the angle deviation does not exceed 0.2°, otherwise it will affect the accuracy of the detection. This requires the combined adjustment of various auxiliary equipment such as translation stages, rotation stages, and laser levels, which is not only costly, but also disposable. Once the position moves, it must be readjusted, which is inefficient. The second method uses a fixture to keep the two terahertz corrugated horn antennas in the same straight line, and a motion mechanism can be used to achieve long-distance movement. However, the disadvantages are also obvious. Since the fixture includes a fixed end, a movable end, and a motion mechanism, and they are connected in series in the same straight line, the fixture is relatively long, while the terahertz horn antenna is relatively small, especially in the 500GHz to 1100GHz frequency band, which is usually only 10mm to 20mm long, much smaller than the length of the fixture. In order to be able to dock with the test instrument, a straight waveguide has to be connected behind the terahertz corrugated horn antenna, which greatly increases the energy loss of the terahertz wave in the test path. For example, a 20mm long straight waveguide usually causes half of the energy loss of the 500GHz terahertz wave, which ultimately results in the signal received by the receiving end being too weak to be measured. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a material characteristic testing device and method based on terahertz waves, which solves the technical problems raised in the background technology.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a material characteristic testing device based on terahertz waves, comprising: a transmitting antenna, a base assembly and a receiving antenna; the transmitting antenna and the receiving antenna are respectively connected to two ends of the base assembly through threaded transmission; the axes of the transmitting antenna and the receiving antenna coincide, and both the transmitting antenna and the receiving antenna can move along the axis;

[0008] The horn-mouth surfaces of the transmitting antenna and the receiving antenna are arranged opposite to each other. When the transmitting antenna and the receiving antenna move to the bottom along the axis, the horn-mouth surfaces of the transmitting antenna and the receiving antenna fit together without a gap. The material to be tested is placed on the base assembly. During testing, the material to be tested is clamped by the transmitting antenna and the receiving antenna.

[0009] As a further technical solution, an external thread structure is provided at one end of the outer circumferential surface of the transmitting antenna and the receiving antenna, and the external thread structure is only provided at the four corners of the outer circumferential surface; four limiting planes symmetrical along the center are also provided at one end of the outer circumferential surface of the transmitting antenna and the receiving antenna where the external thread structure is provided.

[0010] As a further technical solution, the other end of the outer circumferential surface of the transmitting antenna and the receiving antenna is a cylindrical surface, the diameter of the cylindrical surface is smaller than the diameter of the external thread structure, and the diameter of the cylindrical surface is larger than the spacing of the limiting planes.

[0011] As a further technical solution, the base assembly includes a base body, which has a U-shaped structure; through holes are symmetrically opened on both sides of the base body, and four bosses are arranged inside the through holes, and the spacing between the bosses is the same as the spacing between the upper limit planes of the transmitting antenna and the receiving antenna.

[0012] As a further technical solution, the base assembly further includes an outer sleeve and a snap ring, wherein the outer sleeve is connected to the base body through the snap ring, the snap ring is a C-shaped structure, and an annular groove is provided on the outer sleeve and the base body, the snap ring is clamped into the annular groove of the outer sleeve and the base body, and the outer sleeve is connected to the base body; an annular scale is provided on the side of the outer sleeve away from the base body;

[0013] An internal thread structure is arranged on the inner side of the outer sleeve, and the internal thread structure is meshed with the external thread structures on the transmitting antenna and the receiving antenna.

[0014] As a further technical solution, the base assembly also includes a bracket, a foot and a locking nut. The bracket is arranged at the bottom of the base body. The bracket and the foot are connected by a thread. The height of the base body is adjusted by the depth of the foot screwed into the bracket. The locking nut is used to lock the depth of the foot screwed into the bracket.

[0015] As a further technical solution, a ruler is provided on the upper surface of the bottom plate of the base body, and the middle position of the ruler is set as a zero scale line. When the flare surfaces of the transmitting antenna and the receiving antenna are seamlessly fitted together, the flare surfaces of the transmitting antenna and the receiving antenna are aligned with the zero scale line; arrow marks are provided on both sides of the base body.

[0016] In a second aspect, the present invention provides a material characteristic testing method based on terahertz waves, based on a material characteristic testing device based on terahertz waves as described in any one of the first aspects, comprising: rotating outer sleeves on both sides of a base body to make a transmitting antenna and a receiving antenna move relative to each other along an axis, when the cylindrical surfaces of the transmitting antenna and the receiving antenna touch the boss of the base body, the flared surfaces of the transmitting antenna and the receiving antenna fit seamlessly and are located at the zero scale line of the ruler, and at the same time, the zero scale line of the annular ruler is aligned with the arrow mark on the base body, thereby completing the normalization calibration of the transmission;

[0017] The substance to be tested is placed in the base body, and the outer sleeves on both sides of the base body are rotated so that the transmitting antenna and the receiving antenna clamp the substance to be tested, and the transmission characteristics of the substance to be tested are tested.

[0018] As a further technical solution, it also includes: placing a metal plate on the base body, rotating the outer sleeves on both sides of the base body so that the transmitting antenna and the receiving antenna clamp the metal plate to achieve normalized calibration of reflection.

[0019] As a further technical solution, the outer sleeves on both sides of the base body are rotated in opposite directions to remove the metal plate, the material to be tested is placed in the base body, and then the outer sleeves on both sides of the base body are rotated so that the transmitting antenna and the receiving antenna clamp the material to be tested to test the reflection characteristics of the material to be tested.

[0020] One or more technical solutions of the present invention have the following beneficial effects:

[0021] 1. The present invention connects the transmitting antenna and the receiving antenna to the two ends of the base assembly through threaded transmission, so that the axes of the transmitting antenna and the receiving antenna coincide and can move along the axes, ensuring that there is no need to rely on the S parameter test module for positioning during the test process, and no need for the cooperation of auxiliary equipment. The equipment purchase cost is reduced, the operation process is simplified, and the complicated adjustment process is avoided, thereby improving the detection efficiency.

[0022] 2. In the present invention, both the transmitting antenna and the receiving antenna adopt a non-standard antenna shape, that is, one end is a standard rectangular waveguide flange interface, and the other end is a flared surface, and the outer circumferential surface of the transmitting antenna and the receiving antenna is set in two parts, one part is with an external thread structure and a limit plane, and the other part is set in a cylindrical shape, and the central cavity of the transmitting antenna and the receiving antenna is a terahertz wave conduction cavity, which consists of three parts: a rectangular waveguide-circular waveguide conversion part, a curved contour corrugated part, and a linear parallel corrugated part. In addition, the present invention designs an outer sleeve that is compatible with the transmitting antenna and the receiving antenna. Rotating the outer sleeve can make the transmitting antenna and the receiving antenna move along the axis, so that the transmitting antenna and the receiving antenna can be directly docked with the test instrument, and no straight waveguide transition is required, which will greatly reduce the energy loss of the terahertz wave in the test path and improve the test accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 A three-dimensional appearance diagram of the material characteristic testing device of the present invention;

[0025] Figure 2 is a cross-sectional view of a material characteristic testing device of the present invention;

[0026] Figure 3 This is an outline diagram of a base assembly of a material characteristic testing device of the present invention;

[0027] Figure 4 A cross-sectional view of a base assembly of a material characteristic testing device of the present invention;

[0028] Figure 5 An exploded view of the material characteristic testing device of the present invention;

[0029] Figure 6 The figure is a diagram of the transmitting antenna of the material characteristic testing device of the present invention;

[0030] Figure 7 The three-view diagram of the transmitting antenna of the material characteristic testing device of the present invention;

[0031] Figure 8 The outer sleeve of the material characteristic testing device of the present invention is an outline view and a cross-sectional view;

[0032] Fig. 9 The figure is the appearance diagram of the base body of the material characteristic testing device of the present invention;

[0033] Fig.10 The three views of the base body of the material characteristic testing device of the present invention;

[0034] Fig.11 A schematic diagram of a circular scale of a material characteristic testing device of the present invention;

[0035] Fig.12 It is a schematic diagram of the thread transmission mechanism of the material characteristic testing device of the present invention;

[0036] Fig.13 is a schematic diagram of the calibration state of the material characteristic testing device of the present invention;

[0037] Fig.14 It is a schematic diagram of the application of the material characteristic testing device of the present invention;

[0038] Among them, 1 is the transmitting antenna; 2 is the base assembly; 2-1 is the outer sleeve; 2-2 is the retaining ring; 2-3 is the base body; 2-4 is the annular scale, 2-5 is the ground foot; 2-6 is the bracket; 2-7 is the locking nut; 3 is the receiving antenna. DETAILED DESCRIPTION

[0039] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0040] Embodiment 1

[0041] This embodiment provides a material characteristic testing device based on terahertz waves, such as Figure 1 and 2 It can be seen from the three-dimensional appearance diagram and cross-sectional view of the material characteristic testing device shown that the material characteristic testing device in this embodiment includes a transmitting antenna 1, a base assembly 2 and a receiving antenna 3, wherein the transmitting antenna and the receiving antenna are respectively connected to the two ends of the base assembly through threaded transmission; the axes of the transmitting antenna and the receiving antenna coincide, and the transmitting antenna and the receiving antenna can both move along the axis, and the horn-mouth surfaces of the transmitting antenna and the receiving antenna are arranged opposite to each other, and when the transmitting antenna and the receiving antenna move to the bottom along the axis, the horn-mouth surfaces of the transmitting antenna and the receiving antenna fit together without a gap; when the material to be tested is placed on the base assembly for testing, the material to be tested is clamped by the transmitting antenna and the receiving antenna.

[0042] Specific: such as Figure 6 and 7The appearance and three-view drawing of the transmitting antenna shown in the figure show that one end of the transmitting antenna and the receiving antenna is a standard rectangular waveguide flange interface that complies with international standards; the other end is a flared surface. The outer circumferential surface of the transmitting antenna and the receiving antenna is divided into two parts, one end of which is provided with an external thread structure with a pitch of 1mm, and the external thread structure is only provided at the four corners of the outer circumferential surface. The end of the outer circumferential surface of the transmitting antenna and the receiving antenna with the external thread structure is also provided with four limiting planes that are symmetrical along the center. In this way, the external thread only exists in the four corners, and the meshing function of the external thread still exists, but the meshing area is reduced.

[0043] The other end of the outer circumferential surface of the transmitting antenna and the receiving antenna is a cylindrical surface, and the diameter of the cylindrical surface is smaller than the diameter of the external thread structure, and the diameter of the cylindrical surface is larger than the spacing of the limiting plane. The central cavity of the transmitting antenna and the receiving antenna is a terahertz wave conduction cavity, which consists of three parts: a rectangular waveguide-circular waveguide conversion part, a curved contour corrugated part, and a linear parallel corrugated part. In this embodiment, the material of the transmitting antenna and the receiving antenna is brass, and the surface coating is gold.

[0044] like Figure 3 and 4 The appearance diagram and cross-sectional view of the base assembly are shown, and the base assembly 2 includes a base body 2-3, an outer sleeve 2-1, a retaining ring 2-2, an annular scale 2-4, a foot 2-5, a bracket 2-6 and a locking nut 2-7, wherein the base body 2-3 is a U-shaped structure and is made of stainless steel. Through holes are symmetrically opened on both sides of the base body, and four bosses are arranged on the inner side of the through holes. The spacing between the bosses is the same as the spacing between the upper limit planes of the transmitting antenna and the receiving antenna. When the outer sleeve rotates, the bosses are used to limit the rotation of the transmitting antenna and the receiving antenna.

[0045] In this embodiment, the outer sleeve is connected to the base body through a snap ring, wherein the snap ring is a C-shaped structure, the material of the snap ring is beryllium bronze, and it has high elasticity after heat treatment. Annular grooves are provided on the outer sleeve and the base body, and the snap ring is inserted into the annular grooves of the outer sleeve and the base body to connect the outer sleeve to the base body, and an annular scale is provided on the side of the outer sleeve away from the base body, and each grid on the annular scale represents a horizontal movement of 0.02 mm. The back of the annular scale has a self-adhesive sticker, which can be optionally attached to the outer sleeve to indicate the movement caused by the rotation of the outer sleeve. When the outer sleeve rotates one circle, the transmitting antenna and the receiving antenna move 1 mm, and arrow marks are provided on both sides of the base body, preferably "→". The annular scale cooperates with "→" to indicate the movement caused by the rotation of the outer sleeve.

[0046] The outer sleeve is made of stainless steel, and an internal thread structure is provided on the inner side of the outer sleeve. The pitch of the internal thread structure is 1mm, and the internal thread structure is meshed with the external thread structure on the transmitting antenna and the receiving antenna. Due to the restriction of the retaining ring 2-2, the outer sleeve 2-1 can only rotate but not translate. When the outer sleeve 2-1 rotates, the thread engagement will generate forces in two directions: horizontal thrust and circumferential force, causing the transmitting antenna and the receiving antenna to translate and rotate, while the four bosses on the base body 2-3 will limit the rotation of the transmitting antenna and the receiving antenna, and finally form a combined force in the horizontal direction, pushing the transmitting antenna and the receiving antenna to move along the axis.

[0047] A ruler is provided on the upper surface of the bottom plate of the base body to display the distance moved by the transmitting antenna and the receiving antenna. The middle position of the ruler is set as the zero scale line. When the horn mouth surfaces of the transmitting antenna and the receiving antenna fit seamlessly, the horn mouth surfaces of the transmitting antenna and the receiving antenna are aligned with the zero scale line. The distance moved can be read by the ruler on the bottom plate of the base body and the annular ruler on the outer sleeve. When the thickness of the material to be tested is small, one end of the antenna can be kept stationary (such as the transmitting antenna is stationary) and only the other end of the antenna can be moved (such as the receiving antenna is stationary); when the thickness of the material to be tested is large, both ends of the antenna can be moved to achieve measurement within a wide range of sizes.

[0048] In this embodiment, the bracket is arranged at the bottom of the base body, and the bracket and the anchor are connected by a threaded connection. The height of the base body is adjusted by the depth of the anchor screwed into the bracket. The locking nut is used to lock the depth of the anchor screwed into the bracket to ensure the stability of the entire device.

[0049] Embodiment 2

[0050] This embodiment provides a material characteristic testing method based on terahertz waves, and a material characteristic testing device based on terahertz waves provided in Embodiment 1, including:

[0051] The outer sleeve 2-1 on both sides of the rotating base body enables the transmitting antenna and the receiving antenna to move relative to each other along the axis through the interaction of the external thread structure, the internal thread structure, the retaining ring, the limit plane and the boss. When the cylindrical surfaces of the transmitting antenna and the receiving antenna touch the boss of the base body, the flared surfaces of the transmitting antenna and the receiving antenna fit seamlessly and are located at the zero scale line of the ruler. At the same time, the zero scale line of the annular ruler is aligned with the arrow mark on the base body to complete the normalization calibration of the transmission.

[0052] like Fig.14As shown, the host controls a pair of S parameter test modules through cables. The two ends of the transmitting antenna and the receiving antenna in this device are respectively connected to the S parameter test modules. After completing the normalization calibration of the transmission, the material to be tested is placed in the base body, and the outer sleeves on both sides of the base body are rotated so that the transmitting antenna and the receiving antenna clamp the material to be tested to test the transmission characteristics of the material to be tested.

[0053] The method further includes: placing a metal plate on the base body, rotating the outer sleeves on both sides of the base body so that the transmitting antenna and the receiving antenna clamp the metal plate to achieve normalized calibration of reflection. Rotating the outer sleeves on both sides of the base body in the opposite direction to remove the metal plate, placing the substance to be tested in the base body, and then rotating the outer sleeves on both sides of the base body so that the transmitting antenna and the receiving antenna clamp the substance to be tested to test the reflection characteristics of the substance to be tested.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A material characteristic testing device based on terahertz waves, characterized in that: include: Transmitting antenna, base assembly and receiving antenna; The transmitting antenna and the receiving antenna are respectively connected to the two ends of the base assembly through threaded transmission; the axes of the transmitting antenna and the receiving antenna coincide with each other, and both the transmitting antenna and the receiving antenna can move along the axes; The horn-mouth surfaces of the transmitting antenna and the receiving antenna are arranged opposite to each other. When the transmitting antenna and the receiving antenna move to the bottom along the axis, the horn-mouth surfaces of the transmitting antenna and the receiving antenna fit together without a gap. The material to be tested is placed on the base assembly. During testing, the material to be tested is clamped by the transmitting antenna and the receiving antenna.

2. A material characteristic testing device based on terahertz waves as claimed in claim 1, characterized in that: One end of the outer circumferential surface of the transmitting antenna and the receiving antenna is provided with an external thread structure, and the external thread structure is only provided at the four corners of the outer circumferential surface; the end of the outer circumferential surface of the transmitting antenna and the receiving antenna with the external thread structure is also provided with four limiting planes symmetrical along the center.

3. A material characteristic testing device based on terahertz waves as claimed in claim 2, characterized in that: The other end of the outer circumferential surface of the transmitting antenna and the receiving antenna is a cylindrical surface, the diameter of the cylindrical surface is smaller than the diameter of the external thread structure, and the diameter of the cylindrical surface is larger than the spacing of the limiting planes.

4. The material characteristic testing device based on terahertz waves according to claim 1, characterized in that: The base assembly includes a base body, which is in a U-shaped structure; through holes are symmetrically opened on both sides of the base body, and four bosses are arranged inside the through holes, and the spacing between the bosses is the same as the spacing between the upper limit planes of the transmitting antenna and the receiving antenna.

5. The material characteristic testing device based on terahertz waves as claimed in claim 4, characterized in that: The base assembly further includes an outer sleeve and a snap ring, wherein the outer sleeve is connected to the base body via the snap ring, the snap ring is a C-shaped structure, and an annular groove is provided on the outer sleeve and the base body, the snap ring is inserted into the annular groove of the outer sleeve and the base body, and the outer sleeve is connected to the base body; an annular scale is provided on the side of the outer sleeve away from the base body; An internal thread structure is arranged on the inner side of the outer sleeve, and the internal thread structure is meshed with the external thread structures on the transmitting antenna and the receiving antenna.

6. The material characteristic testing device based on terahertz waves as claimed in claim 4, characterized in that: The base assembly also includes a bracket, a foot and a locking nut. The bracket is arranged at the bottom of the base body. The bracket and the foot are connected by a thread. The height of the base body is adjusted by the depth of the foot screwed into the bracket. The locking nut is used to lock the depth of the foot screwed into the bracket.

7. The material characteristic testing device based on terahertz waves as claimed in claim 4, characterized in that: A ruler is provided on the upper surface of the bottom plate of the base body, and the middle position of the ruler is set as a zero scale line. When the horn surfaces of the transmitting antenna and the receiving antenna are seamlessly fitted together, the horn surfaces of the transmitting antenna and the receiving antenna are aligned with the zero scale line; arrow marks are provided on both sides of the base body.

8. A material characteristic testing method based on terahertz waves, based on a material characteristic testing device based on terahertz waves according to any one of claims 1 to 9, characterized in that: include: The outer sleeves on both sides of the base body are rotated to make the transmitting antenna and the receiving antenna move relative to each other along the axis. When the cylindrical surfaces of the transmitting antenna and the receiving antenna touch the boss of the base body, the horn surfaces of the transmitting antenna and the receiving antenna fit together without gaps and are located at the zero scale line of the ruler. At the same time, the zero scale line of the annular ruler is aligned with the arrow mark on the base body, completing the normalization calibration of the transmission; The substance to be tested is placed in the base body, and the outer sleeves on both sides of the base body are rotated so that the transmitting antenna and the receiving antenna clamp the substance to be tested, and the transmission characteristics of the substance to be tested are tested.

9. A material characteristic testing method based on terahertz waves as claimed in claim 9, characterized in that: Also includes: Place the metal plate on the base body, rotate the outer sleeves on both sides of the base body so that the transmitting antenna and the receiving antenna clamp the metal plate to achieve normalized calibration of reflection.

10. The material characteristic testing method based on terahertz wave according to claim 8, characterized in that: Rotate the outer sleeves on both sides of the base body in the opposite direction, remove the metal plate, place the material to be tested in the base body, and then rotate the outer sleeves on both sides of the base body so that the transmitting antenna and the receiving antenna clamp the material to be tested to test the reflection characteristics of the material to be tested.

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