CN216646326U - A Microstrip Metal Crack Detection Sensor Based on Resonance Offset - Google Patents

Abstract

The utility model proposes a microstrip metal crack detection sensor based on resonance offset, which includes a feeder, a resonance patch and a dielectric substrate. The resonance patch is provided with two mutually perpendicular feeding ports, and the feeder is connected to the feeder respectively. On the electrical port, the dielectric substrate is connected under the resonant patch, and a defective ground plane is set under the dielectric substrate. The defective ground plane uses the plane of the metal to be tested as the compensation ground plane at the defect of the defective ground plane, and the defective ground plane is in contact with the compensation ground plane. , when a crack appears on the tested metal, the current path of the tested metal surface will be cut off by the crack, the current on the crack will pass through the defect ground plane and the compensation ground plane, the return path will become longer, and the resonant frequency on the resonant patch will occur. By changing the resonant frequency, the crack information on the metal to be tested can be obtained. The utility model has the advantages of small size, simple structure, low cost, and the metal crack detection sensor is less affected by the metal crack depth and the background environment.

Description

A Microstrip Metal Crack Detection Sensor Based on Resonance Offset

technical field

The utility model relates to the technical field of antennas and sensing, in particular to a microstrip metal crack detection sensor based on resonance offset.

Background technique

Non-destructive testing is a method of inspecting the object under test without harming the internal tissue of the object or affecting the performance of the object under test. Changes in reactions such as heat, sound, light, electricity, and magnetism caused by abnormal internal structure or defects in the material, with the help of modern technology and equipment, physical or chemical methods can be used to measure the internal and surface structure, state and defects of the object. shape is checked and tested.

Among them, the contact measurement needs to be completed through the contact between the measuring instrument and the object to be measured. The change of the output of the measuring instrument is reliably related to the physical change of the structure of the measuring part. degree of damage. The built-in sensor technology in contact measurement is a new type of detection technology developed in recent years. These sensors can be reliably combined with the structure under test, and at the same time, it will not cause any damage to the component and will not affect its performance in any way.

The metal crack detection technology based on resonant frequency shift takes the measured metal plane as a component of the microstrip resonant unit, that is, the ground plane. When a crack appears on the metal, the current path on its surface will be changed by the crack, thereby affecting the resonant frequency of the resonant unit. By analyzing the direction and magnitude of the resonant frequency shift, the crack information of the metal can be obtained.

At present, the metal crack detection sensors in the form of microstrip based on resonance offset are mainly divided into two types: wired detection and wireless detection. The radar cross section (RCS) of the sensor is used to monitor the sensor resonant frequency change. Wireless detection can determine the crack direction by changing the polarization direction of the transmitted signal, but it has high requirements on the background environment. When the background environment is more complex, the measured RCS value will be affected. Wired detection is not affected by the environment, but it is difficult to monitor the crack width and direction at the same time. The utility model uses the form of dual ports and dual frequencies to monitor the crack width and direction.

SUMMARY OF THE INVENTION

The purpose of the utility model is to provide a metal crack detection sensor with small volume, simple structure, low cost, and little influence by the metal crack depth and background environment.

A microstrip metal crack detection sensor based on resonance offset is characterized in that: it includes a feeder, a resonance patch and a dielectric substrate, the resonance patch is provided with two mutually perpendicular feeding ports, the feeders are respectively Connected to the feed port, the dielectric substrate is connected under the resonant patch, and a defective ground plane is set under the dielectric substrate, and the defective ground plane uses the plane of the metal to be tested as the compensation ground plane at the defect of the defective ground plane , the defect ground plane is in contact with the compensation ground plane. When a crack occurs on the tested metal, the current path of the tested metal surface will be cut off by the crack, and the current on the crack passes through the defect ground plane and the compensation ground plane. The return path becomes longer, the resonant frequency on the resonant patch changes, and the crack information on the tested metal is obtained through the change of the resonant frequency. A rectangular defect surface is set under the defect ground plane, and the rectangular defect surface is set inside. There are compensating stickers, the compensating stickers form a "well" shape in the rectangular defect surface, and the offset of the resonance frequency when adjusting the crack width is realized by changing the width between the compensating stickers.

In the above structure: the defect ground plane uses the plane of the metal to be tested as the compensation ground plane at the defect of the defect ground plane, and the defect ground plane and the compensation ground plane are contacted for measurement. When a crack appears on the tested metal, the current on the tested metal surface The path will be cut off by the crack, the current on the crack will pass through the defect ground plane and the compensation ground plane, the return path will become longer, the resonant frequency on the resonant patch will change, and the crack information on the tested metal will be obtained by changing the resonant frequency. When it is necessary to adjust the offset of the resonant frequency when the crack width is adjusted, it can be realized by changing the width between the "wells" formed by the compensation stickers in the rectangular defect surface.

Further: the length of the "well" type compensation sticker is 50mm and 40mm, and the width is 4mm and 1.25mm respectively. The horizontal and vertical compensation stickers are evenly distributed in the area corresponding to the rectangular resonant patch.

In the above structure: when the resonant frequency shifts, the compensation sticker is put into the "well" type structure and adjusted so that the resonant frequency tends to be normal.

Further: the length of the "well" type compensation sticker is 0, the width is 0, and the rectangular defect surface is a complete rectangle.

In the above structure: when the resonant frequency appears normal, it is not necessary to put the compensation sticker into the "well" type structure, that is, there is no supplementary sticker in the rectangular defect surface.

Further: the resonant patch is a rectangular resonant patch with unequal length and width, and the two feed ports on the rectangular resonant patch are coupled on one long side and one wide side of the rectangular resonant patch through feed lines feed.

In the above structure: the resonant patch adopts a rectangular resonant patch with unequal length and width to realize dual-frequency dual polarization, and the coupling feeding is carried out on one long side and one wide side of the rectangular resonant patch through the feeder, realizing dual-frequency dual-polarization. Frequency dual-port feeding can effectively distinguish transverse cracks and longitudinal cracks.

Further: the feed mode of the two feed ports on the long side and the broad side of the rectangular resonant patch is "T" type coupling feeding, and the distance between the feed line and the rectangular resonant patch is 0.2mm.

In the above structure: the "T" type coupling feeding method is adopted, the input impedance can be changed by adjusting its length Ls, width s and spacing d, and the final feed line is connected with a 50 ohm microstrip line to obtain a line with lower cross polarization polarized electric field.

Further: the length of the long side of the rectangular resonant patch is 50mm, and the width of the broad side of the rectangular resonant patch is 40mm. By changing the length L of the long side and the width W of the wide side of the rectangular resonant patch, the the two original resonant frequencies.

In the above structure, the resonant patch adopts a rectangular shape, and by changing the length of the long side and the length of the broad side of the rectangular resonant patch, the two original resonant frequencies on the rectangular resonant patch can be adjusted.

Further: the thickness of the dielectric substrate is 1 mm, and the dielectric constant is 2.2.

In the above structure, the thickness of the dielectric substrate is 1 mm, which makes the overall structure of the sensor compact and saves installation space.

Compared with the prior art, the beneficial effects of the present utility model are:

The utility model can effectively distinguish transverse cracks and longitudinal cracks by setting dual-frequency dual-port feeding; the defect ground plane and the compensation sticker can make the resonance frequency offset positively correlated with the crack width under the condition of any crack depth and length . The structure is compact, the thickness is only 1mm, the microstrip patch is simple to manufacture, and the cost is low.

Description of drawings

Fig. 1 is the general structure top view of the present utility model;

Fig. 2 is the hierarchical structure intention of the present utility model;

3 is a schematic diagram of the defective ground with compensation stickers in Embodiment 1 of the present utility model;

4 is a schematic diagram of a defective ground in Embodiment 2 of the present utility model;

5 is a schematic diagram of a rectangular microstrip patch in an embodiment of the present invention;

6 is the relationship between the width of the metal transverse crack and the resonant frequency offset of the two feeding ports in Embodiment 1 of the present utility model;

Fig. 7 is the relationship between the metal longitudinal crack width and the resonant frequency offset of two feed ports in Embodiment 1 of the present utility model;

8 is the relationship between the width of the metal transverse crack and the resonant frequency offset of the two feed ports in Embodiment 2 of the present utility model;

FIG. 9 shows the relationship between the longitudinal crack width of the metal and the resonant frequency offset of the two feeding ports in the second embodiment of the present invention.

List of reference numbers:

1. Feeder; 2. Resonant patch; 21. Compensation sticker; 3. Dielectric substrate; 4. Metal to be tested; 5. Defective ground plane.

Detailed ways

Below in conjunction with the accompanying drawings and specific embodiments, the present utility model is described in further detail:

As shown in Figures 1-5, a microstrip metal crack detection sensor based on resonance offset includes a feeder 1, a resonant patch and a dielectric substrate 3. The resonant patch is provided with two mutually perpendicular feeders port, the feeder 1 is respectively connected to the feeder port, the dielectric substrate 3 is connected under the resonant patch, and a defective ground plane 5 is arranged under the dielectric substrate 3, and the defective ground plane 5 will be the tested metal 4 The plane of the defect ground plane 5 is used as the compensation ground plane at the defect of the defect ground plane 5. The defect ground plane 5 is in contact with the compensation ground plane. When a crack occurs on the tested metal 4, the current path on the surface of the tested metal 4 will be cut off by the crack. , the current on the crack passes through the defect ground plane 5 and the compensation ground plane, the return path becomes longer, the resonant frequency on the resonant patch changes, and the crack information on the tested metal 4 is obtained through the change of the resonant frequency, so A rectangular defect surface is provided below the defect ground plane 5, and a compensation sticker 21 is arranged in the rectangular defect surface. The compensation sticker 21 forms a "well" shape in the rectangular defect surface. The width of , realizes the offset of the resonant frequency when adjusting the crack width. In the above structure: the defect ground plane 5 uses the plane of the tested metal 4 as the compensation ground plane at the defect of the defect ground plane 5, and the defect ground plane 5 and the compensation ground plane are contacted for measurement. The current path on the surface of the measurement metal 4 will be cut off by the crack, the current on the crack will pass through the defect ground plane 5 and the compensation ground plane, the return path will become longer, and the resonant frequency on the resonant patch will change. To measure the crack information on the metal 4, when it is necessary to adjust the offset of the resonant frequency when the crack width is required, it is realized by changing the width between the “wells” formed by the compensation sticker 21 in the rectangular defect surface.

In this embodiment: the resonant patch is a rectangular resonant patch 2 with unequal length and width, and the two feed ports on the rectangular resonant patch 2 are connected to one long side of the rectangular resonant patch 2 through the feed line 1 The resonant patch adopts rectangular resonant patch 2 with unequal length and width to realize dual-frequency dual polarization, and feed line 1 on one long side and one wide side of the rectangular resonant patch 2 Coupling feeding is carried out on the upper part, and dual-frequency dual-port feeding is realized, which can effectively distinguish transverse cracks and longitudinal cracks.

In this embodiment: the feeding mode of the two feed ports on the long side and the broad side of the rectangular resonant patch 2 is "T" type coupling feeding, and the distance between the feed line 1 and the rectangular resonant patch 2 is 0.2mm; adopt the "T" type coupling feeding method, the input impedance can be changed by adjusting its length Ls, width s and spacing d, and finally the feeder 1 is connected with a 50 ohm microstrip line to obtain a line with lower cross polarization polarized electric field.

In this embodiment: the length of the long side of the rectangular resonant patch 2 is 50 mm, and the width of the broad side of the rectangular resonant patch 2 is 40 mm. By changing the length and width of the long side of the rectangular resonant patch 2, the rectangular The two original resonant frequencies on the resonant patch 2; the resonant patch adopts a rectangular shape, and by changing the long side length L and the wide side length W of the rectangular resonant patch 2, the two original resonant frequencies on the rectangular resonant patch 2 can be adjusted. Resonant frequency.

In this embodiment, the thickness of the dielectric substrate 3 is 1 mm, and the dielectric constant is 2.2; the thickness of the dielectric substrate 3 is 1 mm, which makes the overall structure of the sensor compact and saves installation space.

The utility model utilizes the microstrip resonance unit to realize the function of the metal crack sensor, can distinguish the crack direction and the crack width to a certain extent, and has the advantages of small volume, simple structure, low cost and the like.

Example 1

In this embodiment, the sensor includes a three-layer structure, namely the resonant patch 2, the feeder 1, the dielectric substrate 3, and the defect ground plane 5. Below the defect ground plane 5 is the tested metal 4. The surface of the tested metal 4 needs to be The planes 5 are in close contact.

The size of rectangular resonant patch 2 is L=50mm, W=40mm, “T” type coupling feeder 1 length Ls1=37mm, Ls2=46mm, width s=0.5mm, coupling spacing d=0.2mm, microstrip line width b= 5mm, 50 ohm microstrip line width a=3mm.

The thickness of the dielectric substrate 3 is 1 mm, and the dielectric constant is 2.2.

In this embodiment, the lengths of the “well” type compensation strips 21 are respectively 50 mm and 40 mm, and the widths are respectively x=4 mm and y=1.25 mm. distributed.

In this embodiment, modeling optimization simulation is performed in HFSS, and the simulation result of the metal crack sensor is obtained as shown in Figure 6-7.

FIG. 6 shows the resonance frequency offset corresponding to the longitudinal cracks of different widths in this embodiment.

FIG. 7 shows the resonant frequency offsets corresponding to transverse cracks of different widths in this embodiment.

Example 2

In this embodiment, the sensor includes a three-layer structure, namely the resonant patch 2, the feeder 1, the dielectric substrate 3, and the defect ground plane 5. Below the defect ground plane 5 is the tested metal 4. The surface of the tested metal 4 needs to be The planes 5 are in close contact.

The dimensions of the top rectangular resonant patch 2 are L=50mm, W=40mm, “T” type coupling feeder 1 length Ls1=37mm, Ls2=46mm, width s=0.5mm, coupling spacing d=0.2mm, microstrip line width b =5mm, 50 ohm microstrip line width a=3mm.

The thickness of the dielectric substrate 3 is 1 mm, and the dielectric constant is 2.2.

The width of the "well" type compensation sticker 21 is 0, that is, there is no intermediate compensation sticker 21, and the "defect" of the defective ground plane 5 is a complete rectangle.

In this embodiment, modeling optimization simulation is performed in HFSS, and the simulation result of the metal crack sensor is obtained as shown in Figure 8-9.

FIG. 8 shows the resonant frequency shifts corresponding to transverse cracks of different widths in this embodiment.

FIG. 9 shows the resonance frequency offsets corresponding to longitudinal cracks of different widths in this embodiment.

The above are only preferred embodiments of the present utility model, and are not intended to limit the present utility model in any other form, and any modifications or equivalent changes made according to the technical essence of the present utility model still belong to the present utility model. Scope of protection claimed.

Claims (7)

1. A microstrip metal crack detection sensor based on resonance offset, characterized in that: it comprises a feeder (1), a resonance patch (2) and a dielectric substrate (3), and the resonance patch (2) is provided with There are two mutually perpendicular feed ports, the feed lines (1) are respectively connected to the feed ports, the dielectric substrate (3) is connected under the resonant patch (2), and the dielectric substrate (3) is provided below Defective ground plane (5), the defective ground plane (5) uses the plane of the tested metal (4) as the compensation ground plane at the defect of the defective ground plane (5), and the defective ground plane (5) is connected to the compensation ground plane. Plane contact, a rectangular defect surface is provided below the defect ground plane (5), a compensation sticker (21) is provided in the rectangular defect surface, and the compensation sticker (21) forms a "well" in the rectangular defect surface Type, by changing the width between the compensating stickers (21) to realize the offset of the resonance frequency when adjusting the crack width. 2. A microstrip metal crack detection sensor based on resonance offset according to claim 1, characterized in that: the length of the "well" type compensation sticker (21) is respectively 50mm and 40mm, and the width is respectively 4mm and 40mm. 1.25mm, the horizontal and vertical compensation stickers (21) are evenly distributed within the area corresponding to the rectangular resonant patch (2). 3. A microstrip metal crack detection sensor based on resonance offset according to claim 1, characterized in that: the length of the "well" type compensation sticker (21) is 0, the width is 0, and the rectangular defect surface is a complete rectangle. 4. A microstrip metal crack detection sensor based on resonance offset according to claim 1, characterized in that: the resonance patch (2) is a rectangular resonance patch (2) with unequal length and width, so The two feeding ports on the rectangular resonant patch (2) are coupled to feed on one long side and one wide side of the rectangular resonant patch (2) through feed lines (1). 5 . A microstrip metal crack detection sensor based on resonance offset according to claim 4 , characterized in that: the two feeding ports on the long side and the wide side of the rectangular resonant patch (2) are fed with power. 6 . The method is "T" type coupling feeding, and the distance between the feeding line (1) and the rectangular resonant patch (2) is 0.2 mm. 6. A microstrip metal crack detection sensor based on resonance offset according to claim 5, characterized in that: the long side of the rectangular resonance patch (2) is 50 mm, and the rectangular resonance patch (2) The width of the broad side is 40mm. By changing the length of the long side and the width of the broad side of the rectangular resonant patch (2), the two original resonance frequencies on the rectangular resonant patch (2) are adjusted. 7. A microstrip metal crack detection sensor based on resonance offset according to claim 1, characterized in that: the thickness of the dielectric substrate (3) is 1 mm, and the dielectric constant is 2.2.

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