Open ring resonator loaded waveguide type microwave detection probe
By using a resonant ring assembly loaded with an open-loop resonator in a waveguide-type microwave inspection probe, the problem of insufficient electromagnetic field focusing ability of microwave resonators in waveguide systems is solved, enabling efficient and non-destructive testing of minute defects in metal components.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- XIAN UNIV OF TECH
- Filing Date
- 2025-07-24
- Publication Date
- 2026-07-10
Smart Images
Figure CN224480431U_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of nondestructive testing technology and relates to a waveguide-type microwave testing probe loaded with an open-loop resonator. Background Technology
[0002] Metal components in major engineering fields such as aerospace, rail transportation, and nuclear power equipment are critical structural and functional parts, and their quality directly affects the safety, reliability, and service life of the equipment. Accurate detection of defects in these metal components is crucial for ensuring equipment reliability and extending its lifespan. However, due to the high manufacturing cost of these metal components, destructive testing is not cost-effective. Therefore, in practice, non-destructive testing techniques are generally used for defect detection in these metals.
[0003] Traditional nondestructive testing techniques such as ultrasonic testing and eddy current testing, while widely used, still have limitations in terms of high resolution, real-time performance, and adaptability to complex curved surfaces, making it difficult to detect minute defects in metal parts. Meanwhile, defect detection methods based on microwave sensing have attracted considerable attention due to their advantages of being non-contact, highly sensitive, and having strong penetration.
[0004] Microwave-based nondestructive testing (NDT) of metal defects is an emerging and efficient detection technology. Its principle is to utilize the reflection, scattering, and transmission characteristics of microwaves interacting with metallic materials to detect defects on or inside the metal surface. However, existing microwave resonators have poor ability to concentrate electric and magnetic fields in waveguide systems, resulting in weak electric and magnetic fields that are difficult to detect minute defects within metal components. Utility Model Content
[0005] The purpose of this invention is to provide waveguide-type microwave detection with open-ring resonator loading, which solves the problem in the prior art that the waveguide system has poor ability to concentrate electric and magnetic fields and cannot provide sufficiently large electric and magnetic fields for non-destructive testing of metals.
[0006] The technical solution adopted in this utility model is a waveguide-type microwave detection probe loaded with an open-ring resonator, including a waveguide, a connecting flange fixedly connected to one end of the waveguide, a dielectric plate fixedly connected to the other side of the connecting flange opposite to the waveguide, a groove opened in the center of the dielectric plate, an annular copper sheet fixedly connected in the groove, and a resonant ring assembly fixedly connected in the annular copper sheet.
[0007] The features of this utility model also include:
[0008] The resonant ring assembly includes a first resonant ring fixed within a ring-shaped copper sheet and a second resonant ring that is set independently.
[0009] Both the first and second resonant rings are parallel to the dielectric plate.
[0010] The notches of the first and second resonant rings are in opposite directions.
[0011] The first and second resonant rings are identical in size and shape.
[0012] A rigid substrate is provided on the outside of the first resonant ring, and the rigid substrate is fixedly connected inside the annular copper sheet. A flexible substrate is provided on the outside of the second resonant ring.
[0013] Both the first and second resonant rings are made of copper, and the first resonant ring is fabricated on a hard substrate using photolithography.
[0014] The thickness of the first and second resonant rings is 0.018 mm.
[0015] The beneficial effects of this utility model are:
[0016] This invention incorporates two resonant rings parallel to the detection plane and with opposite opening directions between the waveguide and the metal being tested. Under the influence of the magnetic field provided by the waveguide, second harmonics can be efficiently excited, resulting in a wider resonant bandwidth and greater reflection amplitude for the two resonant rings. This generates stronger electric and magnetic fields, which is beneficial for detecting defects within metallic materials. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the structure of the waveguide-type microwave detection probe loaded with an open-loop resonator according to this utility model;
[0018] Figure 2 This is a cross-sectional view of the waveguide-type microwave detection probe loaded with an open-ring resonator according to this utility model.
[0019] In the figure: 1. Waveguide; 2. Connecting flange; 3. Dielectric plate; 4. Annular copper sheet; 5. Resonant ring assembly; 6. First resonant ring; 7. Second resonant ring; 8. Rigid substrate; 9. Flexible substrate. Detailed Implementation
[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.
[0021] Example 1:
[0022] like Figure 1 and Figure 2 As shown, the waveguide-type microwave detection probe loaded with an open-loop resonator includes a waveguide 1. One end of the waveguide 1 is fixedly connected to a connecting flange 2. On the other side of the connecting flange 2 opposite to the waveguide 1, a dielectric plate 3 is fixedly connected. A groove is opened in the center of the dielectric plate 3. An annular copper sheet 4 is fixedly connected in the groove. A resonant ring assembly 5 is fixedly connected in the annular copper sheet 4.
[0023] In conventional techniques, waveguide 1 is usually placed directly against the metal being tested. However, this device has a resonant ring assembly 5 at the front end of waveguide 1. The electromagnetic field can be focused through the resonant ring to obtain a wider resonant frequency band and a larger reflection amplitude, which is beneficial for the detection of minute defects.
[0024] Example 2:
[0025] like Figure 1 and Figure 2 As shown, the waveguide-type microwave detection probe loaded with an open-loop resonator includes a waveguide 1. One end of the waveguide 1 is fixedly connected to a connecting flange 2. On the other side of the connecting flange 2 opposite to the waveguide 1, a dielectric plate 3 is fixedly connected. A groove is opened in the center of the dielectric plate 3. An annular copper sheet 4 is fixedly connected in the groove. A resonant ring assembly 5 is fixedly connected in the annular copper sheet 4.
[0026] The resonant ring assembly 5 includes a first resonant ring 6 fixedly connected within an annular copper sheet 4 and a second resonant ring 7 that is independently set.
[0027] The first resonant ring 6 and the second resonant ring 7 are both parallel to the dielectric plate 3.
[0028] The notches of the first resonant ring 6 and the second resonant ring 7 are in opposite directions.
[0029] In this application, metal damage detection is performed using resonant rings parallel to the metal being tested. When the magnetic field provided by the waveguide passes perpendicularly through the first resonant ring 6 and the second resonant ring 7, induced currents are generated in the two resonant rings according to Faraday's law of electromagnetic induction, thereby generating induced capacitances at the openings of the resonant rings. At this time, the first resonant ring 6 and the second resonant ring 7 are each equivalent to an LC resonant structure.
[0030] The magnetic field passing through the overlapping resonant rings induces resonance between the first resonant ring 6 and the second resonant ring 7, achieving energy localization. Under a strong field, the metal ring-dielectric substrate interface of this device causes the electron motion on the surface of the resonant rings to exhibit a nonlinear response. Furthermore, the opposite opening directions of the first resonant ring 6 and the second resonant ring 7 disrupt the symmetry. The combination of these two elements can efficiently excite second harmonics, enabling the overlapping resonant rings to obtain a wider resonant frequency band and a larger reflection amplitude.
[0031] The wide resonant bandwidth and large reflection amplitude make the resonant ring more sensitive to changes in electromagnetic properties caused by minute defects. When cracks, foreign objects, or structural changes occur inside the metal, the local dielectric constant, conductivity, or geometric dimensions of the metal will change, thereby affecting the distribution of the surrounding electromagnetic field. This is reflected in the resonant ring as a minute change in amplitude or phase, enabling the detection of metal damage under non-destructive conditions.
[0032] Example 3:
[0033] like Figure 1and Figure 2 As shown, the waveguide-type microwave detection probe loaded with an open-loop resonator includes a waveguide 1. One end of the waveguide 1 is fixedly connected to a connecting flange 2. On the other side of the connecting flange 2 opposite to the waveguide 1, a dielectric plate 3 is fixedly connected. A groove is opened in the center of the dielectric plate 3. An annular copper sheet 4 is fixedly connected in the groove. A resonant ring assembly 5 is fixedly connected in the annular copper sheet 4.
[0034] The resonant ring assembly 5 includes a first resonant ring 6 fixedly connected within an annular copper sheet 4 and a second resonant ring 7 that is independently set.
[0035] The first resonant ring 6 and the second resonant ring 7 are both parallel to the dielectric plate 3.
[0036] The notches of the first resonant ring 6 and the second resonant ring 7 are in opposite directions.
[0037] The first resonant ring 6 and the second resonant ring 7 are the same size and shape.
[0038] A rigid substrate 8 is provided on the outer side of the first resonant ring 6, and the rigid substrate 8 is fixedly connected to the annular copper sheet 4. A flexible substrate 9 is provided on the outer side of the second resonant ring 7.
[0039] Both the first resonant ring 6 and the second resonant ring 7 are made of copper. The first resonant ring 6 is processed on the hard substrate 8 by photolithography.
[0040] The thickness of the first resonant ring 6 and the second resonant ring 7 is 0.018 mm.
[0041] The first resonant ring 6 is fixed inside the annular copper sheet by a rigid substrate 8, so that the position of the first resonant ring 6 and the waveguide 1 is fixed, which can stably generate the induced capacitance and facilitate metal detection.
[0042] The second resonant ring 7 is wrapped by a flexible substrate 9, the main component of which is polyimide. Polyimide has excellent adhesion properties and can be firmly fixed to the metal surface, ensuring that the second resonant ring 7 will not shift or fall off during the detection process, thus avoiding detection signal deviation caused by the movement of the second resonant ring 7.
[0043] Example 4:
[0044] Based on Example 3:
[0045] The waveguide-type microwave detection probe loaded with the open-ring resonator involved in Embodiment 3 was used, and the metal detection was performed in the frequency band of 12.4GHz to 18GHz. The long side and wide side of the rectangular waveguide are 15.799×7.899mm, and the flange is 33.3×33.3mm.
[0046] The parameters for the resonant ring assembly are set as shown in the table below:
[0047]
[0048] When this device is used for metal damage detection, the maximum value of the excited electric field strength is 47457.848 V / m, the maximum value of the magnetic field strength is 439.103 A / m, and the maximum value of the negative absolute value of the reflection coefficient S11 is 24 dB.
[0049] Example 5:
[0050] Based on Example 3:
[0051] The waveguide-type microwave detection probe loaded with the open-ring resonator involved in Embodiment 3 was used, and the metal detection was performed in the frequency band of 12.4GHz to 18GHz. The long side and wide side of the rectangular waveguide are 15.799×7.899mm, and the flange is 33.3×33.3mm.
[0052] The parameters for the resonant ring assembly are set as shown in the table below:
[0053]
[0054] When this device is used for metal damage detection, the maximum value of the excited electric field strength is 15757.829 V / m, the maximum value of the magnetic field strength is 293.231 A / m, and the maximum value of the negative absolute value of the reflection coefficient S11 is 18 dB.
[0055] Example 6:
[0056] Based on Example 3:
[0057] The waveguide-type microwave detection probe loaded with the open-ring resonator involved in Embodiment 3 was used, and the metal detection was performed in the frequency band of 12.4GHz to 18GHz. The long side and wide side of the rectangular waveguide are 15.799×7.899mm, and the flange is 33.3×33.3mm.
[0058] The parameters for the resonant ring assembly are set as shown in the table below:
[0059]
[0060] When this device is used for metal damage detection, the maximum value of the excited electric field strength is 25863.896 V / m, the maximum value of the magnetic field strength is 175.029 A / m, and the maximum value of the negative absolute value of the reflection coefficient S11 is 17.5 dB.
[0061] Example 7:
[0062] Based on Example 3:
[0063] The waveguide-type microwave detection probe loaded with the open-ring resonator involved in Embodiment 3 was used, and the metal detection was performed in the frequency band of 12.4GHz to 18GHz. The long side and wide side of the rectangular waveguide are 15.799×7.899mm, and the flange is 33.3×33.3mm.
[0064] The parameters for the resonant ring assembly are set as shown in the table below:
[0065]
[0066] When this device is used for metal damage detection, the maximum value of the excited electric field strength is 14125.625 V / m, the maximum value of the magnetic field strength is 134.329 A / m, and the maximum value of the negative absolute value of the reflection coefficient S11 is 34 dB.
[0067] To verify the significant advancements of this device over conventional techniques, metal damage detection was performed using the same waveguides employed in Examples 4 to 7. The experimental records are shown in the table below:
[0068]
[0069] In control group 1, no resonant ring is placed between the waveguide and the metal under test, and the waveguide is 1 mm away from the metal under test.
[0070] In control group 2, no resonant ring is placed between the waveguide and the metal under test, and the waveguide is in close contact with the metal under test.
[0071] Compared with the two control groups, the metal damage detection performed in Examples 4 to 7 using this device showed that the electric and magnetic field strengths, as well as the maximum absolute value of the negative value of the reflection coefficient S11, were all greater than those achieved using only waveguides in conventional techniques. Therefore, in metal non-destructive testing, the electric and magnetic fields generated by this device can significantly increase the electric and magnetic field distortions caused by internal metal defects. Furthermore, the small value of |S11| indicates high sensitivity of this device. In conclusion, this device can more accurately detect the presence of internal defects in metals without damaging them.
[0072] Working principle:
[0073] The detection probe provided in this application mainly consists of two parts: a waveguide and a resonant ring assembly. The waveguide provides a magnetic field, and the resonant ring assembly amplifies and concentrates the magnetic field provided by the waveguide, thereby detecting minute defects inside the metal.
[0074] The resonant ring assembly of this application consists of two resonant rings of equal size, but with their opening directions opposite. When a magnetic field provided by a waveguide passes through the resonant rings, the change in magnetic induction intensity causes electrons inside the rings to move under the influence of the magnetic field, thus generating an induced current within the rings. Simultaneously, since both resonant rings have notches, the charges accumulated at these notches are opposite, resulting in an induced capacitance. Because both induced current and capacitance exist within the resonant rings, they are equivalent to an LC resonant structure. Under the influence of the magnetic field passing through the two rings, resonance occurs between them. Under the influence of a strong magnetic field, electrons on the surface of the resonant rings within the annular copper sheet exhibit a nonlinear response. Furthermore, the opposite opening directions of the two rings disrupt symmetry. The combination of these factors allows for efficient excitation of second harmonics, resulting in a wider resonant frequency band and a larger reflection amplitude, which is beneficial for detecting minute defects.
Claims
1. A waveguide-type microwave detection probe loaded with an open-loop resonator, characterized in that, The device includes a waveguide (1), one end of which is fixedly connected to a connecting flange (2), and the other side of the connecting flange (2) opposite to the waveguide (1) is fixedly connected to a dielectric plate (3). A groove is provided in the center of the dielectric plate (3), and an annular copper sheet (4) is fixedly connected in the groove. A resonant ring assembly (5) is fixedly connected in the annular copper sheet (4).
2. The waveguide-type microwave detection probe loaded with an open-loop resonator according to claim 1, characterized in that, The resonant ring assembly (5) includes a first resonant ring (6) fixedly connected within an annular copper sheet (4) and a second resonant ring (7) set independently.
3. The waveguide-type microwave detection probe loaded with an open-loop resonator according to claim 2, characterized in that, The first resonant ring (6) and the second resonant ring (7) are both parallel to the dielectric plate (3).
4. The waveguide-type microwave detection probe loaded with an open-loop resonator according to claim 3, characterized in that, The notches of the first resonant ring (6) and the second resonant ring (7) are in opposite directions.
5. The waveguide-type microwave detection probe loaded with an open-loop resonator according to claim 3, characterized in that, The first resonant ring (6) and the second resonant ring (7) are the same in size and shape.
6. The waveguide-type microwave detection probe loaded with an open-loop resonator according to claim 3, characterized in that, A hard substrate (8) is provided on the outside of the first resonant ring (6), and the hard substrate (8) is fixedly connected to the annular copper sheet (4). A soft substrate (9) is provided on the outside of the second resonant ring (7).
7. The waveguide-type microwave detection probe loaded with an open-loop resonator according to claim 6, characterized in that, The first resonant ring (6) and the second resonant ring (7) are both made of copper. The first resonant ring (6) is processed on a hard substrate (8) by photolithography.
8. The waveguide-type microwave detection probe loaded with an open-loop resonator according to claim 7, characterized in that, The thickness of the first resonant ring (6) and the second resonant ring (7) is 0.018 mm.