Magnetic field probe with high electric field rejection ratio

Abstract

The utility model discloses a magnetic field probe with a high electric field rejection ratio, and belongs to the technical field of magnetic field probes. The utility model solves the problem of how to provide a magnetic field probe which is simple in structure, good in electric field suppression ratio, low in flatness and good in detection performance. The antenna comprises a dielectric substrate layer, the top surface and the bottom surface of the dielectric substrate layer are respectively provided with a first metal layer and a second metal layer, the same positions of the dielectric substrate layer, the first metal layer and the second metal layer are all provided with via holes, the first metal layer is of a strip-shaped structure, and the first metal layer is composed of an opening annular part and a straight part. A via hole in the first metal layer is formed in the open annular part, and an open hole corresponding to the annular part is formed in the position, close to the via hole, of the second metal layer. According to the utility model, the working frequency range is wide, a wide frequency range can be covered in practical application, and possibility is provided for detecting magnetic field signals with different frequencies.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of magnetic field probe, specifically relates to a magnetic field probe with high electric field rejection ratio. BACKGROUND

[0002] With the development of electronic information technology, electromagnetic field test technology becomes a research hotspot, and near-field scanning technology has developed rapidly, and the most important one is the design of the near-field scanning magnetic field probe, and the near-field scanning technology is widely applied in wireless communication, radio frequency technology, electronic equipment test and other fields, and can be used for detecting signal interference and electromagnetic radiation leakage of circuit board and other problems.

[0003] In the prior art, the microwave journal (small wideband magnetic field probe simulation and design. Microwave journal, 2022, 38(01): 57-61) discloses a near-field magnetic field probe, which can be used for integrated circuit electromagnetic radiation emission measurement and radiation source positioning in electronic equipment. The probe adopts four-layer printed circuit board design, and the dielectric material adopts high-performance and low-loss Rogers4350B material, which ensures simple structure and miniaturization; the south China university of technology journal (natural science edition) (ultra-wideband active magnetic field probe design applied to near-field measurement. Journal of south China university of technology (natural science edition), 2021, 49(6): 131-140) discloses a small, high bandwidth and non-contact active magnetic field probe. The active magnetic field probe is made of multi-layer printed circuit board (PCB), and on the basis of the passive probe, an active amplifier module and a matching power management chip are added to improve the transmission gain of the ultra-wideband type probe.

[0004] However, the near-field probe structure disclosed in the prior art is relatively complex, and how to provide a magnetic field probe with simple structure, good electric field rejection ratio, low flatness and good detection performance is a problem to be solved. Utility model content

[0005] In view of the problem of how to provide a magnetic field probe with simple structure, good electric field rejection ratio, low flatness and good detection performance in the prior art, the utility model provides a magnetic field probe with high electric field rejection ratio.

[0006] The technical scheme adopted by the utility model is as follows:

[0007] The magnetic field probe with high electric field suppression ratio comprises a dielectric substrate layer, the top surface and bottom surface of the dielectric substrate layer are respectively provided with a first metal layer and a second metal layer, the dielectric substrate layer, the first metal layer and the second metal layer are all provided with a via hole at the same position, the first metal layer is in a strip structure, and the first metal layer is composed of an open ring-shaped part and a straight part, the via hole on the first metal layer is arranged on the open ring-shaped part, and the second metal layer is provided with an opening corresponding to the ring-shaped part near the via hole.

[0008] Preferably, the thickness of the dielectric substrate layer is 0.254 mm, the thickness of the first metal layer is 18 μm, and the thickness of the second metal layer is 35 μm.

[0009] Preferably, the dielectric substrate layer is an RO4350B plate, and the first metal layer and the second metal layer are both copper plates.

[0010] Preferably, the dielectric substrate layer and the second metal layer are both in a T-shaped structure and have the same shape and size.

[0011] Preferably, the dielectric substrate layer is composed of a first horizontal part and a first vertical part to form a T-shaped structure, the length of the first horizontal part is 20 mm, and the width is 12 mm; the length of the first vertical part is 8 mm, and the width is 8 mm.

[0012] After the technical scheme is adopted, the dielectric substrate layer and the second metal layer are both arranged in a T-shaped structure, so that the space utilization and layout can be optimized, and the manufacturing and assembly are facilitated.

[0013] Preferably, the opening is in a T-shaped structure, and the opening is composed of a second horizontal part and a second vertical part to form a T-shaped structure, the length of the second horizontal part is 1.2 mm, and the width is 0.4 mm; the length of the second vertical part is 0.8 mm, and the width is 0.5 mm.

[0014] After the technical scheme is adopted, the opening is in a T-shaped structure, so that the electromagnetic coupling effect can be enhanced, and the signal transmission and matching can be improved.

[0015] Preferably, the width of the first metal layer is 0.1 mm.

[0016] Preferably, the radius of the via hole is 0.04 mm.

[0017] In summary, due to the adoption of the above technical scheme, the utility model has the following beneficial effects:

[0018] The utility model discloses a kind of T-shaped structure's near-field magnetic field probe, for detecting electromagnetic radiation. Model is established by HFSS electromagnetic simulation software, and the relevant parameters of its calculation. Conclusion shows that, in working frequency 100MHz-6GHz, electric field suppression average is all above 15dB, and most of frequency point satisfies >17dB. The magnetic field probe magnetic field fluctuation in band is about ±5dB, range is 1GHz-5GHz. Dielectric material selects high-performance, low-loss Rogers4350B material, ensure simple structure and miniaturization. This means that the probe can work stably in wider frequency range, can be applicable to magnetic field detection scene under multiple frequencies, with good frequency adaptability, can cover wider frequency range in practical application, provide the possibility for detecting different frequency magnetic field signal. BRIEF DESCRIPTION OF DRAWINGS

[0019] The utility model will be explained by example and with reference to the drawings, wherein:

[0020] Figure 1 It is the structural schematic diagram of the utility model;

[0021] Figure 2 It is Figure 1 The split diagram of each layer in it;

[0022] Figure 3 It is Figure 1 The structural schematic diagram of first metal layer in it;

[0023] Figure 4 It is Figure 1 The structural schematic diagram of second metal layer in it;

[0024] Figure 5 It is the size mark drawing of first metal layer and second metal layer in the utility model;

[0025] Figure 6 It is the position relation diagram of microstrip line when the utility model is used;

[0026] Figure 7 It is the magnetic field test result drawing of the utility model;

[0027] Figure 8 It is the electric field test result drawing of the utility model;

[0028] Figure 9 It is the electric field suppression ratio result drawing of the utility model;

[0029] Wherein: 1-first metal layer, 101-straight part, 102-opening annular part, 2-dielectric substrate layer, 3-second metal layer, 301-first transverse part, 302-second longitudinal part, 4-opening, 401-second transverse part, 402-second longitudinal part, 5-via hole. DETAILED DESCRIPTION

[0030] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the accompanying drawings of the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0031] In the description of the embodiments of the present application, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly placed when the utility model product is used, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" and the like are only used for differentiation in description and cannot be understood as indicating or implying relative importance.

[0032] The following will be combined Figures 1-9 The utility model is described in detail.

[0033] As Figures 1-4 shown, a magnetic field probe with high electric field suppression ratio, including dielectric substrate layer 2, the top surface and bottom surface of dielectric substrate layer 2 are provided with first metal layer 1 and second metal layer 3 respectively, the same position on dielectric substrate layer 2, first metal layer 1 and second metal layer 3 is provided with via 5, the first metal layer 1 is banded structure, and the first metal layer 1 is composed of open ring-shaped part 102 and straight part 101, the via 5 on first metal layer 1 is arranged in open ring-shaped part 102, the second metal layer 3 is provided with the opening 4 corresponding with ring-shaped part 102 near the via 5.It needs to be explained that the via 5 on dielectric substrate layer 2, first metal layer 1 and second metal layer 3 can be composed of a vertical channel by overlapping, and the dielectric substrate layer 2, first metal layer 1 and second metal layer 3 can form closed loop through the channel.

[0034] In the embodiment, the thickness of the dielectric substrate layer 2 is 0.254 mm, the thickness of the first metal layer 1 is 18 μm, and the thickness of the second metal layer 3 is 35 μm.

[0035] In this embodiment, the dielectric substrate layer 2 is an RO4350B board (dielectric constant is 3.48, dielectric loss tangent is 0.0037), and the first metal layer 1 and the second metal layer 3 are both copper plates.

[0036] In this embodiment, the dielectric substrate layer 2 and the second metal layer 3 have the same shape and size, and both the dielectric substrate layer 2 and the second metal layer 3 are T-shaped structures.

[0037] In another embodiment, the dielectric substrate layer 2 is composed of a first lateral portion 301 and a first longitudinal portion 302 forming a T-shaped structure, such as... Figure 5 As shown, Figure 5 W1: 20mm; L1: 12mm; W2: 8mm; L2: 8mm; a: 1.2 mm; b: 0.4mm; c: 0.8mm; r (radius): 0.04mm; aa: 0.5mm; d: 0.1mm; that is, the length of the first transverse portion 301 is 20mm and the width is 12mm; the length of the first longitudinal portion 302 is 8mm and the width is 8mm.

[0038] In another embodiment, the opening 4 is further described as a T-shaped structure, and the second transverse portion 401 and the second longitudinal portion 402 of the opening 4 form a T-shaped structure, as shown below. Figure 5 As shown, the second transverse portion 401 has a length of 1.2 mm and a width of 0.4 mm; the second longitudinal portion 402 has a length of 0.8 mm and a width of 0.5 mm. Figure 5 As shown, the shape of the groove formed by the annular opening 102 of the first metal layer 1 matches the shape and size of the second transverse portion 401. The length of the first metal layer 1 is equal to the length from the end edge of the dielectric substrate layer 2 to the via 5 on the dielectric substrate layer 2, so that the end face of the first metal layer 1 after it connects to the dielectric substrate layer 2 is on the same plane as the side surface of the first metal layer 1, and the vias 5 on the first metal layer 1 and the vias 5 on the dielectric substrate layer 2 can overlap to form a channel.

[0039] In another embodiment, the bandwidth of the first metal layer 1 is further 0.1 mm.

[0040] In another embodiment, the radius of the via 5 is further 0.04 mm.

[0041] The specific method of using this utility model is as follows:

[0042] Simulation diagram as follows Figure 6As shown, using a two-port vector network analyzer test, and the probe is fixed at a height of 1mm on the test board. Specifically, the via 5 is welded with the SMA joint. One end of the microstrip line is connected to port one of the vector network analyzer (VNA), and the other end is connected to a 50Ω matching load; the output end of the magnetic field probe is connected to port two of the vector network analyzer, the bottom flat plate is the microstrip line, and the two ports of the vector network analyzer are connected to port one and port three as shown, wherein port one is used as an excitation end to feed the microstrip line with an excitation signal to make the microstrip line work and generate electromagnetic radiation, and the electromagnetic radiation generated by the microstrip line is measured by the probe and returned to the vector network analyzer through port three, thereby completing the test process, and port two is a matching end;

[0043] When performing magnetic field strength testing, the probe is suspended and parallel to the microstrip line, and the distance between the probe and the microstrip line to be tested is 1mm. The scattering parameter S21 from port 1 to port 2 can be used for testing, and the test results are as shown in Figure 7 The results can be used to represent the ability of the probe to couple the magnetic field.

[0044] Electric field strength test: rotate the probe by 90 degrees, and the rest remains unchanged. The test method is consistent with the method of testing the magnetic field. At this time, the magnetic field energy cannot be coupled by the probe, and the measured S21 is used to represent the electric field energy coupled by the probe. The test results are as shown in Figure 8 According to the obtained data and images, the magnetic field of the magnetic field probe is in the frequency band range of 1GHz-5GHz with a deviation of ±5dB, which meets the design index. According to the definition of the electric field suppression ratio, the amplitude of the magnetic field energy and the amplitude of the electric field energy are plotted to obtain the image of the electric field suppression ratio, and the results are as shown in Figure 9 From Figure 9 It can be seen that the average electric field suppression is more than 15dB, and most of the frequency points meet the design index of >17dB.

[0045] In the technical field involved in the utility model, the specific implementation technical scheme presents the possibility of diversification. As for the magnetic field probe, its design is not limited to a single form. For example, the flexible variation of the probe ring size, the appropriate replacement of the medium substrate material, and many different forms can ensure that they do not deviate from the core target and key points pursued by the utility model, and have the potential ability to achieve the purpose of the invention, and are fully qualified to be included in the protection scope and comprehensive consideration of the utility model. This fully demonstrates that the utility model has high flexibility and wide inclusiveness in dealing with various different technical paths, and provides a broad space for further expansion and optimization of technology.

[0046] The above embodiments only express the specific implementation of the present application, which is described in more detail and specifically, but cannot be understood as a limitation to the protection scope of the present application. It should be noted that for those skilled in the art, without departing from the technical concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application.

Claims

1. A magnetic field probe having a high electric field rejection ratio, characterized by: The application relates to a medium substrate layer (2) provided with a first metal layer (1) and a second metal layer (3) on the top surface and the bottom surface respectively, and a via (5) is arranged at the same position on the medium substrate layer (2), the first metal layer (1) and the second metal layer (3); the first metal layer (1) is in a strip structure and is composed of an open ring-shaped part (102) and a straight part (101), the via (5) on the first metal layer (1) is arranged on the open ring-shaped part (102), and the second metal layer (3) is provided with an opening (4) corresponding to the ring-shaped part (102) near the via (5).

2. A magnetic field probe with a high electric field rejection ratio according to claim 1, characterized in that: The thickness of the medium substrate layer (2) is 0.254 mm, the thickness of the first metal layer (1) is 18 mu m, and the thickness of the second metal layer (3) is 35 mu m.

3. The magnetic field probe with high electric field rejection ratio according to claim 1, characterized in that: The medium substrate layer (2) is an RO4350B plate, and the first metal layer (1) and the second metal layer (3) are both copper plates.

4. The magnetic field probe having a high electric field rejection ratio according to claim 1, characterized in that: The medium substrate layer (2) and the second metal layer (3) are in the same shape and size and are both in T-shaped structures.

5. A magnetic field probe having a high electric field rejection ratio according to claim 4, characterized in that: The medium substrate layer (2) is composed of a first horizontal part (301) and a first vertical part (302) to form a T-shaped structure, the length of the first horizontal part (301) is 20 mm, and the width is 12 mm; the length of the first vertical part (302) is 8 mm, and the width is 8 mm.

6. A magnetic field probe having a high electric field rejection ratio according to claim 5, characterized in that: The opening (4) is in a T-shaped structure, and a second horizontal part (401) and a second vertical part (402) of the opening (4) form a T-shaped structure, the length of the second horizontal part (401) is 1.2 mm, and the width is 0.4 mm; the length of the second vertical part (402) is 0.8 mm, and the width is 0.5 mm.

7. A magnetic field probe having a high electric field rejection ratio according to any one of claims 1 to 6, characterized in that: The width of the first metal layer (1) is 0.1 mm.

8. A magnetic field probe having a high electric field rejection ratio according to any one of claims 1 to 6, characterized in that: The radius of the via (5) is 0.04 mm.

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