A complementary split resonant ring electromagnetic detection unit, detection system and detection method

Abstract

The present invention discloses a complementary open resonant ring electromagnetic detection unit, a detection system and a detection method. The detection unit includes a plurality of shielded through holes opened on a substrate to form a substrate integrated waveguide resonant cavity, a complementary open resonant ring electromagnetic structure is arranged in the center of the substrate integrated waveguide resonant cavity, and the complementary open resonant ring electromagnetic structure is two nested and mutually isolated open rings; one side of the substrate integrated waveguide resonant cavity on the upper surface of the substrate is connected to a microstrip line, and the other side of the microstrip line is connected to a main feeding radio frequency connector; one side of the substrate integrated waveguide resonant cavity on the lower surface of the substrate is connected to two coplanar waveguide center conductors, and the two coplanar waveguide center conductors and their coplanar waveguide gaps form a coplanar waveguide transmission line with a preset impedance, and the other end of the coplanar waveguide transmission line is connected to a sub-feed radio frequency connector; the main feeding radio frequency connector and the sub-feed radio frequency connector are orthogonal and distributed on the upper and lower surfaces of the substrate. By introducing a sub-feed circuit in the electromagnetic detection unit, the detection sensitivity is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal welding surface defect detection, and specifically designs an improved complementary split ring resonator (CSRR) electromagnetic detection unit, a detection system and a detection method. Background Art

[0002] Nondestructive testing technology aims to quickly and reliably detect, test or evaluate the discontinuity or characteristic difference of materials or structures without destroying the normal performance of the materials and components being tested. In industries such as nuclear power plants, aviation, aerospace, pressure vessels, railways, ships, weapon systems, etc., the damage and failure of any component may cause significant danger or economic losses.

[0003] As we all know, the electromagnetic detection unit at the front end of the microwave non-destructive testing device is mainly a passive circuit. Therefore, the amplitude of the resonance peak during the detection process is relatively small, and when the defective structure is detected, the amplitude of the resonance peak will be even smaller, which greatly reduces the sensitivity of the detection. Summary of the invention

[0004] In order to overcome the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide an improved complementary open resonant ring electromagnetic detection unit, a detection system and a detection method, by introducing a sub-feeding circuit into the electromagnetic detection unit, thereby improving the detection sensitivity of the complementary open resonant ring electromagnetic detection unit.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A complementary open resonant ring electromagnetic detection unit comprises a substrate, a plurality of substrate integrated waveguide resonant cavity shielding through holes 10 opened on the substrate form a substrate integrated waveguide resonant cavity 5, a complementary open resonant ring electromagnetic structure 9 is arranged at the central position of the substrate integrated waveguide resonant cavity 5, and the complementary open resonant ring electromagnetic structure 9 is two nested and mutually isolated open rings; one side of the substrate integrated waveguide resonant cavity 5 on the upper surface of the substrate is connected to a microstrip line 2 through a transition structure 3, and the other side of the microstrip line 2 is connected to a main feeding radio frequency connector 1, and radio frequency connector grounding through holes are opened around the main feeding radio frequency connector 1 6, realizing the electrical connection between the upper and lower metal layers of the substrate; the substrate integrated waveguide resonant cavity 5 on the lower surface of the substrate is connected to two coplanar waveguide center conductors 7 on the side adjacent to the side connected to the microstrip line 2 on the upper surface, and the two coplanar waveguide center conductors 7 and the coplanar waveguide gap 8 therebetween form a coplanar waveguide transmission line with a preset impedance, and the other end of the coplanar waveguide transmission line is connected to the sub-feed RF connector 4, and the sub-feed RF connector 4 is surrounded by an RF connector grounding through hole 6, realizing the electrical connection between the upper and lower metal layers of the substrate; the main feeding RF connector 1 and the sub-feed RF connector 4 are orthogonal and are distributed on the upper and lower surfaces of the substrate.

[0007] In the complementary open resonant ring electromagnetic structure 9, the inner ring length L4 is 1.2 mm, the width L3 is 1 mm, and the opening spacing S2 is 0.6 mm; the outer ring length L2 is 2 mm, the width L1 is 1.8 mm, and the opening spacing S1 is 0.4 mm; the spacing W between the outer and inner rings of the open ring is 0.2 mm.

[0008] The substrate integrated waveguide resonant cavity 5 forms an approximately closed rectangular metal cavity through a plurality of substrate integrated waveguide resonant cavity shielding through holes 10 and metal layers on the upper and lower surfaces of the substrate.

[0009] A defect nondestructive detection system includes the complementary open resonant ring electromagnetic detection unit, a vector network analyzer 11 connected to the main feeding radio frequency connector 1 of the complementary open resonant ring electromagnetic detection unit, and a phase shifter 14, an amplifier 13 and a frequency source 12 connected in sequence to the sub-feeding radio frequency connector 4 of the complementary open resonant ring electromagnetic detection unit.

[0010] The detection method of the defect non-destructive detection system is as follows: first, the complementary open resonant ring electromagnetic detection unit is placed close to the detection piece 15, and a gap is left between the complementary open resonant ring electromagnetic structure 9 and the detection surface of the detection piece 15; then, the microwave non-destructive detection calibration is performed, the complementary open resonant ring electromagnetic structure 9 is placed at a position without defects of the detection piece 15, the amplifier 13 and the phase shifter 14 are adjusted, and the resonance peak f on the vector network analyzer 11 is observed. 1 The change of the resonance peak f 1 The amplitude is less than -20dB, and the calibration work is completed; start to move the complementary open resonant ring electromagnetic detection unit in parallel, and keep a gap between the complementary open resonant ring electromagnetic structure 9 and the detection member 15. If the resonance peak f on the vector network analyzer 11 is found 1 The presence of an obvious frequency deviation indicates that there is a defect on the surface of the test piece 15 , and the defect position of the test piece 15 is marked; repeat the above operation to complete the detection of the defect of the test piece 15 .

[0011] Compared with the prior art, the present invention has the following advantages:

[0012] 1) The improved complementary open resonant ring electromagnetic detection unit of the present invention can reduce the coupling of the feeding transmission line outside the substrate integrated waveguide cavity through the design of the orthogonal skew feeding structure. At the same time, since two signals enter the substrate integrated waveguide resonant cavity, the feeding signal can be enhanced through intra-cavity coupling;

[0013] 2) The transition from microstrip to substrate integrated waveguide structure resonant cavity adopts grounded coplanar waveguide transmission line, which greatly reduces the volume of the circuit;

[0014] 3) The amplifier and phase shifter in the defect nondestructive detection system can realize flexible adjustment of signal amplitude and phase, so that the sensitivity of the electromagnetic detection unit can be effectively improved by adjusting the gain of the amplifier and the phase control of the phase shifter;

[0015] 4) During the inspection process, keep a safe distance from the inspection part to avoid creating new defects on the inspection part. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the upper surface structure of the complementary open resonant ring electromagnetic detection unit of the present invention.

[0017] Figure 2 It is a schematic diagram of the lower surface structure of the complementary open resonant ring electromagnetic detection unit of the present invention.

[0018] Figure 3 This is a diagram of the electromagnetic structure of a complementary open resonant ring.

[0019] Figure 4 This is a composition diagram of the defect nondestructive detection system of the present invention. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0021] like Figure 1 and Figure 2 As shown, a complementary open resonant ring electromagnetic detection unit of the present invention includes a substrate, a plurality of substrate integrated waveguide resonant cavity shielding through holes 10 opened on the substrate form a substrate integrated waveguide resonant cavity 5, a complementary open resonant ring electromagnetic structure 9 is arranged at the central position of the substrate integrated waveguide resonant cavity 5, and the complementary open resonant ring electromagnetic structure 9 is two nested and mutually isolated open rings; one side of the substrate integrated waveguide resonant cavity 5 on the upper surface of the substrate is connected to a microstrip line 2 through a transition structure 3, and the other side of the microstrip line 2 is connected to a main feeding RF connector 1, and a RF connector connector is opened around the main feeding RF connector 1. The substrate integrated waveguide resonant cavity 5 on the lower surface of the substrate is connected to two coplanar waveguide center conductors 7 on the side adjacent to the side connected to the microstrip line 2 on the upper surface. The two coplanar waveguide center conductors 7 and the coplanar waveguide gap 8 therebetween form a coplanar waveguide transmission line with a preset impedance. The other end of the coplanar waveguide transmission line is connected to the auxiliary feeding RF connector 4. The auxiliary feeding RF connector 4 is surrounded by RF connector grounding through holes 6, which realize the electrical connection of the upper and lower metal layers of the substrate. The main feeding RF connector 1 and the auxiliary feeding RF connector 4 are orthogonal and are distributed on the upper and lower surfaces of the substrate.

[0022] The substrate integrated waveguide resonant cavity 5 forms an approximately closed rectangular metal cavity through a plurality of substrate integrated waveguide resonant cavity shielding through holes 10 and metal layers on the upper and lower surfaces of the substrate.

[0023] like Figure 1 As shown, as a preferred embodiment of the present invention, the transition structure 3 is a slot.

[0024] like Figure 3 As shown, as a preferred embodiment of the present invention, in the complementary open resonant ring electromagnetic structure 9, the inner ring length L4 is 1.2mm, the width L3 is 1mm, and the opening spacing S2 is 0.6mm; the outer ring length L2 is 2mm, the width L1 is 1.8mm, and the opening spacing S1 is 0.4mm; the outer and inner ring spacing W of the open ring is 0.2mm.

[0025] like Figure 4 As shown, a defect nondestructive detection system of the present invention includes the complementary open resonant ring electromagnetic detection unit, a vector network analyzer 11 connected to the main feeding RF connector 1 of the complementary open resonant ring electromagnetic detection unit, and a phase shifter 14, an amplifier 13 and a frequency source 12 connected in sequence to the sub-feeding RF connector 4 of the complementary open resonant ring electromagnetic detection unit.

[0026] The detection method of the defect nondestructive detection system of the present invention is as follows: first, the complementary open resonant ring electromagnetic detection unit is close to the detection piece 15, and the complementary open resonant ring electromagnetic structure 9 is kept at a distance of 0.1 mm from the detection surface of the detection piece 15; then, the microwave nondestructive detection calibration is performed, the complementary open resonant ring electromagnetic structure 9 is placed at a position without defects of the detection piece 15, the amplifier 13 and the phase shifter 14 are adjusted, and the resonance peak f on the vector network analyzer 11 is observed. 1 The change of the resonance peak f 1 The amplitude is less than -20dB, and the calibration work is completed; start parallel movement of the complementary open resonant ring electromagnetic detection unit, and keep the distance between the complementary open resonant ring electromagnetic structure 9 and the detection member 15 less than 0.1mm. If the resonance peak f on the vector network analyzer 11 is found 1 If there is an obvious frequency deviation (greater than 1 MHz), it means that there is a defect on the surface of the test piece 15 , and the defect position of the test piece 15 is marked; repeat the above operation to complete the detection of the defect of the test piece 15 .

Claims

1. A method for detecting a defect non-destructive detection system, the defect non-destructive detection system comprising a complementary split resonant ring electromagnetic detection unit, a vector network analyzer (11) connected to a main feeding radio frequency connector (1) of the complementary split resonant ring electromagnetic detection unit, a phase shifter (14), an amplifier (13) and a frequency source (12) connected in sequence to a sub-feeding radio frequency connector (4) of the complementary split resonant ring electromagnetic detection unit; The complementary open resonant ring electromagnetic detection unit comprises a substrate; a plurality of substrate integrated waveguide resonant cavity shielding through holes (10) opened on the substrate form a substrate integrated waveguide resonant cavity (5); a complementary open resonant ring electromagnetic structure (9) is arranged at the central position of the substrate integrated waveguide resonant cavity (5); the complementary open resonant ring electromagnetic structure (9) is two nested and mutually isolated open rings; one side of the substrate integrated waveguide resonant cavity (5) on the upper surface of the substrate is connected to a microstrip line (2) through a transition structure (3); the other side of the microstrip line (2) is connected to a main feeding radio frequency connector (1); and a radio frequency connector grounding through hole (10) is opened around the main feeding radio frequency connector (1). 6), realizing electrical connection between the upper and lower metal layers of the substrate; the substrate integrated waveguide resonant cavity (5) on the lower surface of the substrate is connected to two coplanar waveguide center conductors (7) on the side adjacent to the side connected to the microstrip line (2) on the upper surface; the two coplanar waveguide center conductors (7) and the coplanar waveguide gap (8) therebetween form a coplanar waveguide transmission line with a preset impedance; the other end of the coplanar waveguide transmission line is connected to a sub-feed RF connector (4); a RF connector grounding through hole (6) is provided around the sub-feed RF connector (4), realizing electrical connection between the upper and lower metal layers of the substrate; the main feed RF connector (1) and the sub-feed RF connector (4) are orthogonal and are distributed on the upper and lower surfaces of the substrate; In the complementary open resonant ring electromagnetic structure (9), the inner ring length L4 is 1.2 mm, the width L3 is 1 mm, and the opening spacing S2 is 0.6 mm; the outer ring length L2 is 2 mm, the width L1 is 1.8 mm, and the opening spacing S1 is 0.4 mm; the spacing W between the outer ring and the inner ring of the open ring is 0.2 mm; Features: The detection method comprises: firstly, placing a complementary open resonant ring electromagnetic detection unit close to a detection piece (15), and leaving a gap between the complementary open resonant ring electromagnetic structure (9) and the detection surface of the detection piece (15); then, performing microwave non-destructive detection calibration, placing the complementary open resonant ring electromagnetic structure (9) at a position where the detection piece (15) has no defects, adjusting the amplifier (13) and the phase shifter (14), observing the change of the resonance peak f1 on the vector network analyzer (11), and completing the calibration when the amplitude of the resonance peak f1 is less than -20 dB; starting to move the complementary open resonant ring electromagnetic detection unit in parallel, and keeping a gap between the complementary open resonant ring electromagnetic structure (9) and the detection piece (15); if it is found that the resonance peak f1 on the vector network analyzer (11) has an obvious frequency deviation, it indicates that there is a defect on the surface of the detection piece (15), and marking the defect position of the detection piece (15); repeating the above operation to complete the detection of the defect of the detection piece (15).

2. The detection method of a defect nondestructive detection system according to claim 1, characterized in that: The substrate integrated waveguide resonant cavity (5) forms an approximately closed rectangular metal cavity through a plurality of substrate integrated waveguide resonant cavity shielding through holes (10) and metal layers on the upper and lower surfaces of the substrate.

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