Two-channel magnetic field probe device for rapid detection of rigid metal surface

Abstract

The invention discloses a dual-channel magnetic field probe device for rapid detection of a rigid metal surface. The dual-channel magnetic field probe device comprises a top layer (5), a first dielectric layer (6), a second dielectric layer (7), a third dielectric layer (8), a fourth dielectric layer (9) and a bottom layer (10) which are sequentially arranged from top to bottom, a matching layer is arranged between the first dielectric layer (6) and the second dielectric layer (7); a transmission part and a gradual change part are arranged between the second dielectric layer (8) and the third dielectric layer (9); the top layer (5) is provided with a coupling part, and the coupling part comprises two grounded coplanar waveguides; the gradual change part comprises two metal transmission lines with the distance from far to near, and the transmission part comprises two parallel metal transmission lines. According to the invention, the electromagnetic characteristics of two positions can be detected when the probe is stepped once.

Description

Technical Field

[0001] This invention relates to magnetic field probe devices, and more particularly to a dual-channel magnetic field probe device for rapid detection of rigid metal surfaces. Background Technology

[0002] As electronic systems evolve towards miniaturization and high-density integration, the number of discrete components, chips, and interconnects on a single platform is surging, leading to increasingly complex local electromagnetic environments. When inspecting rigid metal surfaces, not only is precise measurement of the magnetic field distribution at a single point required, but rapid detection at multiple locations within a limited space is also urgently needed. However, traditional near-field probes face some inherent limitations: First, single-channel probes can only acquire the electromagnetic characteristics of one location per step, resulting in low detection efficiency. Second, while multi-component probes can simultaneously detect two or three components of the electromagnetic field, increasing the acquisition rate of field information at the same spatial location, they do not improve the scanning rate of electromagnetic characteristics at different spatial locations. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a dual-channel magnetic field probe for rapid circuit detection, which allows the probe to detect the electromagnetic characteristics of two positions with each step.

[0004] The objective of this invention is achieved through the following technical solution: a dual-channel magnetic field probe device for rapid detection of rigid metal surfaces, comprising a top layer, a first dielectric layer, a second dielectric layer, a third dielectric layer, a fourth dielectric layer, and a bottom layer arranged sequentially from top to bottom;

[0005] A matching layer is provided between the first dielectric layer and the second dielectric layer; a transmission section and a gradient section are provided between the second dielectric layer and the third dielectric layer;

[0006] The top layer is provided with a coupling section, which includes two grounded coplanar waveguides, namely a first coplanar waveguide and a second coplanar waveguide. The first end of the first coplanar waveguide is connected to a first connection port; the first end of the second coplanar waveguide is connected to a second connection port; and the second ends of the first and second coplanar waveguides are connected to the gradient section.

[0007] The gradient section includes two metal transmission lines with distances from far to near, and the transmission section includes two parallel metal transmission lines; each metal transmission line in the gradient section corresponds to a coplanar waveguide in the coupling section, and the first end of each metal line in the gradient section is connected to the second end of the corresponding coplanar waveguide through a metal via.

[0008] Each metal line in the gradient section is connected to a metal transmission line in the transmission section at its second end. Both metal transmission lines in the transmission section are equipped with a ring-shaped detection structure at their ends. One ring-shaped detection structure serves as the first detection port, and the other ring-shaped detection structure serves as the second detection port.

[0009] The beneficial effects of this invention are as follows: the coupling part adopts a coplanar waveguide structure, the gradient part adopts a transmission line width gradient method, and the transmission part adopts via isolation measures. This allows the probe to have a wide operating bandwidth while effectively reducing harmonic interference and ensuring high isolation between the two channels. The dual-channel design of this probe enables it to detect the electromagnetic characteristics of two positions with each probe step, effectively improving detection efficiency. Attached Figure Description

[0010] Figure 1 This is a schematic diagram illustrating the principle of testing using the probe device of the present invention;

[0011] Figure 2 This is a schematic diagram of the device structure of the present invention;

[0012] Figure 3 This is a schematic diagram illustrating the layering principle of the present invention;

[0013] Figure 4 This is a schematic diagram showing the connection between the coplanar waveguide and the connection port;

[0014] Figure 5 This diagram illustrates a ring-shaped coaxial via array, vias used to suppress coplanar waveguide harmonics, and vias used to suppress transmission line harmonics.

[0015] Figure 6 A schematic diagram showing the dimensions of each layer;

[0016] Figure 7 This is a schematic diagram of the characteristic impedance curve of the terminal time-domain reflectometer;

[0017] Figure 8 This is a schematic diagram of the probe's detection characteristics;

[0018] Figure 9 This is a schematic diagram of the probe's isolation characteristics. Detailed Implementation

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0020] like Figure 1The diagram illustrates the principle of testing using the probe device of this invention. With each probe step, the electromagnetic characteristics of two locations can be detected. Simultaneously, the via array design and tapered transmission line design ensure excellent impedance matching, with a time-domain reflectometer characteristic impedance of 50 (±1.5) Ω. Furthermore, the use of a coplanar waveguide structure from the microwave connector to the transmission line provides the probe with a 10 GHz operating bandwidth. The coupling between the two channels is less than -40 dB, exhibiting high isolation and significantly reducing signal coupling when both channels operate simultaneously.

[0021] like Figures 2-4 As shown, a dual-channel magnetic field probe device for rapid detection of rigid metal surfaces includes a top layer 5, a first dielectric layer 6, a second dielectric layer 7, a third dielectric layer 8, a fourth dielectric layer 9, and a bottom layer 10 arranged sequentially from top to bottom.

[0022] A matching layer is provided between the first dielectric layer 6 and the second dielectric layer 7; a transmission section and a gradient section are provided between the second dielectric layer 8 and the third dielectric layer 9;

[0023] The top layer 5 is provided with a coupling section, which includes two grounded coplanar waveguides, namely a first coplanar waveguide 11 and a second coplanar waveguide 12. The first end of the first coplanar waveguide 11 is connected to the first connection port 3; the first end of the second coplanar waveguide 12 is connected to the second connection port 4; and the second ends of the first coplanar waveguide 11 and the second coplanar waveguide 12 are connected to the gradient section.

[0024] The gradient section includes two metal transmission lines with distances from far to near, and the transmission section includes two parallel metal transmission lines; each metal transmission line in the gradient section corresponds to a coplanar waveguide in the coupling section, and the first end of each metal line in the gradient section is connected to the second end of the corresponding coplanar waveguide through a metal via.

[0025] Each metal line in the gradient section is connected to a metal transmission line in the transmission section at its second end. Both metal transmission lines in the transmission section are equipped with a ring-shaped detection structure at their ends. One ring-shaped detection structure serves as the first detection port 1, and the other ring-shaped detection structure serves as the second detection port 2.

[0026] The probe consists of a coupling section, a gradient section, and a transmission section. The magnetic field induced by the microstrip line on the circuit board is converted into an electrical signal through ports 1 and 2 of the dual magnetic field detection structure. This signal then passes through the transmission section, the gradient section, and the coupling section to reach ports 3 and 4, respectively. This enables the simultaneous extraction of electromagnetic characteristics at two different locations. The probe's structure, components, and operating process are described in detail below.

[0027] As shown in the figure, the probe has a 4-layer PCB structure. Dielectric layers 1 and 4 are made of RO4003, and dielectric layers 2 and 3 are made of RO4350B. The top and bottom layers are both 35-micron thick copper foil. A 2mm wide copper foil cutout is made in the middle of the top and bottom layers to reduce the coupling between the two probes, ensuring high isolation between them and enabling the probe to work normally and effectively.

[0028] The coupling section is located on the top layer and is a grounded coplanar waveguide structure, which has a wide bandwidth. This effectively supports the probe's wideband response. The gradient section and transmission section are located between dielectric layer 2 and dielectric layer 3, forming a 35-micrometer-thick signal transmission line. They are connected to the coupling section via metal vias. To compensate for the impedance loss caused by the metal vias, a coaxial via array is added around the metal vias. Furthermore, in embodiments of this application, vias for suppressing coplanar waveguide harmonics and vias for suppressing transmission line harmonics can also be provided next to the coaxial via array (ring-shaped coaxial via array), such as... Figure 5 As shown;

[0029] The transmission section ends with two ring-shaped detection structures, each ring having an area of ​​1.2 mm². 2 The center-to-center distance is 5.43 mm.

[0030] The matching layer, located between dielectric layer 1 and dielectric layer 2, is made of 35-micrometer-thick copper and its function is to perform impedance matching on the coupled parts. By changing the PCB stack-up information, the matching layer changes the impedance of the coupled parts, thereby achieving impedance matching and keeping the impedance of the coupled parts at 50 (±1.5) Ω.

[0031] In the embodiments of this application, Figure 6 The dimensions of each layer of this application are shown in the table below.

[0032] parameter Dimensions (mm) parameter Dimensions (mm) parameter Dimensions (mm) <![CDATA[w1]]> 11.41 <![CDATA[w6]]> 31.48 <![CDATA[l4]]> 23.39 <![CDATA[w2]]> 22.82 <![CDATA[W7]]> 3.57 <![CDATA[r1]]> 1.1 <![CDATA[w3]]> 40.78 <![CDATA[l1]]> 10 <![CDATA[r2]]> 1.4 <![CDATA[w4]]> 2 <![CDATA[l2]]> 12.57 <![CDATA[r3]]> 1 <![CDATA[w5]]> 8 <![CDATA[l3]]> 5.40 <![CDATA[h1]]> 1.625 <![CDATA[h2]]> 1.86

[0033] In the embodiments of this application, during actual testing, the probe is placed above the rigid metal surface of the system under test; the electromagnetic characteristic parameters detected at both ports are obtained by a vector network analyzer; the probe is moved forward step by step using a scanning frame, and the electromagnetic characteristic information of two points can be detected at each step, thereby realizing rapid near-field scanning of the rigid metal surface of the system under test.

[0034] In the embodiments of this application, the characteristic impedance curve of the terminal time-domain reflectometer is as follows: Figure 7 As shown, this indicates that the probe has a smooth time-domain impedance curve, the characteristic impedance of the transmission line remains essentially consistent across its entire length, signal integrity is good, and it has the ability to detect high-speed signals. The probe's detection characteristics are as follows: Figure 8As shown, this probe has broadband detection characteristics in the 10GHz range.

[0035] After actual testing, the probe's isolation characteristics are as follows: Figure 9 As shown, this indicates that the two channels of the probe have good isolation over a wide frequency range, which greatly avoids signal coupling when the two channels are working simultaneously.

[0036] In summary, this invention employs a coplanar waveguide structure for the coupling section, a transmission line width gradient method for the gradient section, and via isolation measures for the transmission section. This allows the probe to have a wide operating bandwidth while effectively reducing harmonic interference and ensuring high isolation between the two channels. The dual-channel design of this probe enables it to detect the electromagnetic characteristics of two locations on the circuit with each step, effectively improving the efficiency of circuit detection.

[0037] The foregoing description illustrates and describes a preferred embodiment of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A dual-channel magnetic field probe device for rapid detection of rigid metal surfaces, characterized in that: It includes, from top to bottom, a top layer (5), a first dielectric layer (6), a second dielectric layer (7), a third dielectric layer (8), a fourth dielectric layer (9), and a bottom layer (10); A matching layer is provided between the first dielectric layer (6) and the second dielectric layer (7); a transmission section and a gradient section are provided between the second dielectric layer (8) and the third dielectric layer (9); The top layer (5) is provided with a coupling section, which includes two grounded coplanar waveguides, namely a first coplanar waveguide (11) and a second coplanar waveguide (12). The first end of the first coplanar waveguide (11) is connected to the first connection port (3); the first end of the second coplanar waveguide (12) is connected to the second connection port (4); and the second ends of the first coplanar waveguide (11) and the second coplanar waveguide (12) are connected to the gradient section. The gradient section includes two metal transmission lines with distances from far to near, and the transmission section includes two parallel metal transmission lines; each metal transmission line in the gradient section corresponds to a coplanar waveguide in the coupling section, and the first end of each metal line in the gradient section is connected to the second end of the corresponding coplanar waveguide through a metal via. Each metal line in the gradient section is connected to a metal transmission line of the transmission section at its second end. Both metal transmission lines of the transmission section are provided with a ring-shaped detection structure at their ends. One ring-shaped detection structure serves as the first detection port (1), and the other ring-shaped detection structure serves as the second detection port (2).

2. The dual-channel magnetic field probe device for rapid detection of rigid metal surfaces according to claim 1, characterized in that: The first dielectric layer (6) and the fourth dielectric layer (9) are RO4350B dielectric layers.

3. The dual-channel magnetic field probe device for rapid detection of rigid metal surfaces according to claim 1, characterized in that: The second dielectric layer (7) and the third dielectric layer (8) are RO4003 dielectric layers.

4. The dual-channel magnetic field probe device for rapid detection of rigid metal surfaces according to claim 1, characterized in that: The top layer (5) and the bottom layer (10) are copper foil layers.

5. A dual-channel magnetic field probe device for rapid detection of rigid metal surfaces according to claim 4, characterized in that: A strip groove for hollowing out the copper layer is provided between the top layer (5) and the bottom layer (10), and the width of the strip groove is 2mm.

6. The dual-channel magnetic field probe device for rapid detection of rigid metal surfaces according to claim 1, characterized in that: The thickness of the metal transmission line is 35 micrometers.

7. A dual-channel magnetic field probe device for rapid detection of rigid metal surfaces according to claim 1, characterized in that: The matching layer is made of 35-micrometer-thick copper and its function is to perform impedance matching on the coupling part.

8. A dual-channel magnetic field probe device for rapid detection of rigid metal surfaces according to claim 1, characterized in that: To compensate for the impedance loss caused by the metal vias, a coaxial via array is added around each of the metal vias.

Images