A complex permittivity testing device based on electric field compression cylindrical cavity

Abstract

The application belongs to the technical field of microwave and millimeter wave material electromagnetic parameter testing, and particularly relates to a complex permittivity testing device based on an electric field compression cylindrical cavity. The device comprises a closed cylindrical resonant cavity shell. A ring-shaped magnetic medium material is arranged in the cylindrical resonant cavity shell. The ring-shaped magnetic medium material is fixed to the bottom wall of the cylindrical resonant cavity and coaxial with the cylindrical resonant cavity shell, and the height of the ring-shaped magnetic medium material is consistent with the height of the cylindrical resonant cavity shell. The electric field of the cylindrical resonant cavity is compressed in the central region of the cavity by the ring-shaped magnetic medium material, so that the accuracy of testing the complex permittivity of low-sensitivity dielectric materials by the cylindrical resonant cavity is improved.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic parameter testing technology for microwave and millimeter-wave materials, specifically relating to a complex permittivity testing device based on an electric field-compressed cylindrical cavity, which is used to test the complex permittivity of low-sensitivity dielectric materials. Background Technology

[0002] Microwave dielectric materials are widely used in military and civilian industries such as electronic communications, radar detection, and biomedicine. The properties of dielectric materials are crucial factors determining the development of microelectronics and semiconductor manufacturing technologies. Accurate measurement of the electromagnetic parameters of dielectric materials plays a vital role in the development of wireless communication technologies and microwave / millimeter-wave circuit integration. Currently, the main methods for testing the complex permittivity are the network parameter method and the resonance method.

[0003] Commonly used network parameter methods include the transmission reflection method, the terminal short-circuit method, and the free-space method. These methods have a wide test frequency band and many test frequencies, but their test accuracy is generally lower than that of the resonance method. Commonly used resonance methods include the cylindrical cavity method, the stripline method, the quasi-optical cavity method, and the dielectric resonator method. Compared with network parameter testing methods, resonance methods have fewer test frequencies but higher accuracy. Among them, the cylindrical cavity method, where a dielectric is inserted into the center of the cavity during testing, does not change the symmetry and independence of the field, and is therefore widely used in the measurement of complex permittivity.

[0004] Existing cylindrical cavity methods for testing complex permittivity often employ conventional cylindrical cavities with both ends short-circuited and no filling in the middle. During testing, the sample needs to be placed in the exact center of the cylindrical cavity. However, conventional cylindrical cavities cannot compress the electric field at the center of the cavity. Therefore, the change in complex permittivity of low-sensitivity dielectric materials is relatively small, resulting in low accuracy of the test results. Summary of the Invention

[0005] The purpose of this invention is to provide a complex permittivity testing device based on an electric field-compressed cylindrical cavity, so as to solve the problem of low accuracy of complex permittivity when testing low-sensitivity dielectric materials using the existing cylindrical cavity method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A cylindrical cavity complex permittivity testing device based on electric field compression includes a closed cylindrical resonant cavity shell;

[0008] The cylindrical resonant cavity housing contains an annular magnetic medium material, which is fixed to the bottom wall of the cylindrical resonant cavity and coaxial with the cylindrical resonant cavity housing; its height is consistent with the internal height of the cylindrical resonant cavity housing.

[0009] The bottom wall of the cylindrical resonant cavity shell is provided with two coupling holes. The two coupling holes are located on the same diameter and are located on both sides of the annular magnetic dielectric material. One coupling hole is used to place the coupling ring receiving device, and the other coupling hole is used to place the coupling ring excitation device.

[0010] A through hole is made at the center of the bottom and top walls of the cylindrical resonant cavity shell. The through holes in the top and bottom walls are combined to form a cylindrical area for placing the low-sensitivity test material.

[0011] Furthermore, the through holes opened on the bottom and top walls of the cylindrical resonant cavity housing are circular holes with a diameter of 0.8 mm to 2 mm.

[0012] Furthermore, the through holes opened on the bottom and top walls of the cylindrical resonant cavity shell are preferably 1 mm in diameter to keep the electric field of the cylindrical resonant cavity from being damaged.

[0013] Furthermore, the two coupling holes on the bottom wall are symmetrical about the center point of the bottom wall.

[0014] Furthermore, the inner wall of the cylindrical resonant cavity housing is silver-plated to improve the quality factor of the resonant cavity.

[0015] Furthermore, during testing, the size of the test material should be appropriate to the size of the area where the test material is placed, so that it is placed in a closed cylindrical resonant cavity.

[0016] By adopting the above technical solution, the present invention has the following beneficial effects:

[0017] 1. The present invention provides an annular magnetic dielectric material inside a cylindrical resonant cavity shell. The annular magnetic dielectric material is fixed to the bottom wall of the cylindrical resonant cavity and coaxial with the cylindrical resonant cavity shell, and its height is consistent with the internal height of the cylindrical resonant cavity shell. The annular magnetic dielectric material compresses the electric field of the cylindrical resonant cavity into the central region of the cavity, thereby improving the accuracy of testing the complex permittivity of low-sensitivity dielectric materials in the cylindrical resonant cavity.

[0018] 2. The present invention provides a cylindrical resonant cavity housing, and the inner wall of the housing is silver-plated, which improves the quality factor of the resonant cavity and enables more accurate testing.

[0019] 3. The testing device of the present invention achieves different electric field compression efficiencies by selecting dielectric materials with different magnetic permeability or designing according to the size of the annular dielectric material, so as to meet the needs of testing the complex permittivity of different low-sensitivity dielectric materials. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the complex permittivity testing device based on electric field compression of a cylindrical cavity, as shown in the embodiment.

[0021] Figure 2 This is a schematic diagram of the top wall of the complex permittivity testing device based on electric field compression of a cylindrical cavity, as shown in the embodiment.

[0022] Figure 3 Schematic diagram of the bottom wall of the inner wall of the complex permittivity testing device based on electric field compression of a cylindrical cavity;

[0023] Figure 4 A schematic diagram of a ring-shaped magnetic dielectric material in an embodiment of a complex permittivity testing device based on an electric field-compressed cylindrical cavity;

[0024] Figure 5 As an example, a complex permittivity testing device based on electric field compression of a cylindrical cavity is provided, and electric field comparison curves are provided with and without an annular magnetic medium material; where a is the electric field compression curve without an annular magnetic medium material, and b is the comparison curve with electric field compression with an annular magnetic medium material.

[0025] Figure label:

[0026] 1. Cylindrical resonant cavity shell; 2. Magnetic dielectric material; 1-1. Top wall; 1-2. Bottom wall; 1-2-1. Coupling hole. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings.

[0028] like Figure 1 , Figure 2 , Figure 3 , Figure 4As shown in the figure, this embodiment provides a cylindrical cavity complex permittivity testing device based on electric field compression, including a closed cylindrical resonant cavity shell 1 and a material to be tested. A ring-shaped magnetic medium material 2 is disposed inside the cylindrical resonant cavity shell 1, fixed to the bottom wall of the cylindrical resonant cavity and coaxial with the cylindrical resonant cavity shell 1; its height is consistent with the internal height of the cylindrical resonant cavity shell 1. In this embodiment, the ring-shaped magnetic medium material 2 is a high permeability material, preferably with a relative permeability of 10 or higher and low loss. The bottom wall of the cylindrical resonant cavity shell 1 has two coupling holes 1-2-1, located on the same diameter and on opposite sides of the ring-shaped magnetic medium material 2. One coupling hole is used to house a coupling ring receiving device, and the other coupling hole is used to house a coupling ring excitation device, which connects to an external vector network analyzer. Both the top-wall coupling ring excitation device and the coupling ring excitation device are SMA connector type coupling rings. A through hole is made at the center of the bottom wall 1-2 and the top wall 1-1 of the cylindrical resonant cavity shell. The through holes in the top wall 1-1 and the bottom wall 1-2 are matched to form a cylindrical low-sensitivity test material placement area. The size of the test material is adapted to the test material placement area. In use, the test material is placed into the test material placement area through the through hole in the top wall 1-1 of the cylindrical resonant cavity shell.

[0029] In use, the presence of the toroidal magnetic medium material 2 causes the magnetic field within the cylindrical resonant cavity to be compressed into the toroidal magnetic medium material 2. Combined with the presence of electric walls within the toroidal high-permeability medium, this effectively compresses the electric field within the toroidal magnetic medium material 2. This improves the accuracy of testing the complex permittivity of low-sensitivity dielectric materials using a cylindrical resonant cavity.

[0030] The dimensions of the cylindrical cavity complex permittivity testing device based on electric field compression in this embodiment are as follows:

[0031] The cylindrical resonant cavity shell 1 has a cavity radius of 30mm and a height of 6mm; the annular magnetic medium material 2 has an outer diameter of 9mm, an inner diameter of 4mm, and a height of 6mm; the distance between the two coupling holes and the center point of the bottom wall is 12mm; the diameter of the material to be tested is 1mm, the area where the material to be tested is placed is cylindrical, and the diameter of the two circular through holes on the top and bottom surfaces of the cylinder is 1mm.

[0032] In the TM020 operating mode at the same resonant frequency, the electric field of the complex permittivity testing device of this embodiment with and without the circular magnetic dielectric material 2 is compared. For example... Figure 5 As shown in (a), Figure 5As shown in (b), compared to the electric field strength without the addition of the toroidal magnetic medium material 2, the electric field strength near the center of the cylindrical resonant cavity 1 increases significantly after the addition of the toroidal magnetic medium material 2, reaching approximately four times the electric field strength under the same power conditions. This demonstrates that the cylindrical cavity complex permittivity testing device of this embodiment achieves accurate measurement of low-sensitivity materials by effectively compressing the electric field. Furthermore, the size of the toroidal magnetic medium material can be rationally designed to accommodate the testing of complex permittivity of different low-sensitivity dielectric materials.

[0033] It should be noted that in the above embodiment, the cylindrical resonant cavity housing 1 is provided with an annular magnetic medium material 2. It can be formed by selecting a cylindrical resonant cavity housing with one end open and one end closed, making the annular magnetic medium material 2 inside it, and then making a top cover to form a closed cylindrical resonant cavity.

[0034] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All disclosed features, or steps in all methods or processes, may be combined in any way except for mutually exclusive features and / or steps.

Claims

1. A cylindrical cavity complex permittivity testing device based on electric field compression, comprising a closed cylindrical resonant cavity shell, characterized in that: a toroidal magnetic medium material is arranged in the cylindrical resonant cavity shell, the toroidal magnetic medium material is fixed on the bottom wall of the cylindrical resonant cavity and coaxial with the cylindrical resonant cavity shell, and the height of the toroidal magnetic medium material is consistent with the height of the cylindrical resonant cavity shell; two coupling holes are arranged on the bottom wall of the cylindrical resonant cavity shell, the two coupling holes are located on the same diameter and are respectively located on the two sides of the toroidal magnetic medium material, one of the two coupling holes is used for placing a coupling loop receiving device, and the other coupling hole is used for placing a coupling loop exciting device; a through hole is arranged at the center of the bottom wall and the top wall of the cylindrical resonant cavity shell, and the through hole of the top wall and the through hole of the bottom wall cooperate to form a cylindrical low-sensitivity material placement area.

2. A cylindrical cavity permittivity test device based on electric field compression as claimed in claim 1, characterized in that: The through holes arranged on the bottom wall and the top wall of the cylindrical resonant cavity shell are circular holes with a diameter of 0.8mm to 2mm.

3. A cylindrical cavity permittivity test device based on electric field compression as claimed in claim 1, wherein: The two coupling holes on the bottom wall are symmetrical about the center point of the bottom wall.

4. The cylindrical cavity split post dielectric constant measurement device based on electric field compression of claim 1, wherein: The inner wall of the cylindrical resonant cavity shell is silver-plated.

5. A cylindrical cavity permittivity test device based on electric field compression as defined in claim 1, wherein: The size of the tested material used in the cylindrical cavity complex permittivity testing device based on electric field compression should be adapted to the size of the material placement area.

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