Method and device for testing shielding effectiveness of semi-open cavity shell based on shielding case

Abstract

The invention relates to a shielding case-based semi-open cavity shell shielding effectiveness test method and device, and the method comprises the steps: designing an auxiliary test shielding case matched with a semi-open cavity shell according to the size and shape of the semi-open cavity shell; on the basis of the auxiliary test shielding case, the shielding effect of the half-open emptying cavity shell is tested through a radiation source built-in method; and processing the signal source amplitudes and the frequency spectrograph amplitude values under respective frequency points under two conditions that the semi-open cavity shell exists and the semi-open cavity shell does not exist, so as to obtain the shielding effectiveness of the semi-open cavity shell under the final set device state and position conditions. The problem that the shielding effectiveness of the semi-open cavity shell is difficult to obtain is solved, the shielding characteristic of the semi-open cavity shell is tested and evaluated, and a basis is provided for electromagnetic protection design of internal equipment of the semi-open cavity shell.

Description

Technical Field

[0001] The present invention relates to the field of shielding effectiveness testing, and in particular to a shielding effectiveness testing method and device for a semi-open cavity shell based on a shielding chassis. Background Art

[0002] For electronic information systems, as the number of internal electronic devices continues to increase and the degree of integration increases, the electromagnetic interference generated within the electronic information system is becoming more and more significant. In order to avoid interference between internal electronics, the key to effectively solving the electromagnetic compatibility problem is to divide the distribution of electronic equipment within complex electronic information systems into compartments and shield them separately.

[0003] For some typical electronic information systems, due to assembly requirements, there are a large number of semi-open cavity shell structures. The electronic equipment installed inside is electromagnetically shielded from the outside world through these semi-open cavity structures (which can not only resist external electromagnetic interference, but also prevent internal equipment from causing external interference). However, in actual use, these semi-open cavity shells cannot form a closed structure independently, but need to be assembled with other structures to form a closed structure. In some scenarios, other structures that match these semi-open cavity shell structures are not available. At this time, it is difficult to evaluate the electromagnetic shielding effectiveness of the semi-open cavity shell structure. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method and device for testing the shielding effectiveness of a semi-open cavity shell based on a shielding chassis, thereby solving the deficiencies of the prior art.

[0005] The object of the present invention is achieved by the following technical solution: a method for testing the shielding effectiveness of a semi-open cavity shell based on a shielded chassis, the testing method comprising:

[0006] Step 1: design an auxiliary test shielding chassis matching the semi-open cavity shell according to the size and shape of the semi-open cavity shell;

[0007] Step 2: On the basis of the auxiliary test shielding chassis, the shielding effect of the semi-open cavity shell is tested by the built-in radiation source method;

[0008] Step 3: Under the two conditions of having a semi-open cavity shell and not having a semi-open cavity shell, the signal source amplitude and the spectrum analyzer amplitude value at each frequency point are processed to obtain the shielding effectiveness of the semi-open cavity shell under the final device state and position conditions.

[0009] The step 1 specifically includes the following contents:

[0010] A1. Design the auxiliary test shielding box as a cube or a cuboid with one face being a square face, and the side length of the square face is greater than 3 times the maximum size of the open face of the semi-open cavity shell to be tested, and the parameter of the other side of the cuboid is greater than the side length of the front face;

[0011] A2. In the center of the square surface, a matching assembly hole is opened according to the shape of the open surface of the semi-open cavity shell, and a flange device is set at the opened position;

[0012] A3. A test hole is opened in the center of the side of the assembly hole, and a matching buckled shielding cover is designed. The buckled shielding cover completely closes the test hole, and a through-cabin RF adapter is set in the buckled shielding cover;

[0013] A4. Inside the auxiliary test shielding chassis, a vertical support frame is set at the center of the square surface opposite to the assembly hole. The fixture of the small transmitting antenna and the near-field sensor is fixed at the top of the vertical support frame, and the overall height of the vertical support frame is adjusted to ensure that the small antenna and the near-field sensor can move vertically inside the semi-open cavity shell to be tested;

[0014] A5. High-frequency small absorbing spikes are arranged inside the five surfaces of the auxiliary test shielding chassis except the assembly hole surface to absorb the internal electromagnetic waves.

[0015] The step 2 specifically includes the following contents:

[0016] B1. Fix the semi-open cavity shell and the auxiliary test shielding chassis through the assembly holes, and the two together form an integral closed cavity;

[0017] B2. Fix a small transmitting antenna on the vertical bracket inside the auxiliary test shielding box. The transmitting antenna mouth faces outward through the test hole and is connected to the external signal source through the through-cabin RF adapter on the test hole via the RF line. Move the transmitting antenna inside the overall closed cavity by adjusting the vertical bracket.

[0018] B3. Calibrate the height of the vertical bracket to ensure that the small transmitting antenna is fixed in position;

[0019] B4. Set up a receiving antenna at the distance and angle set in the overall closed cavity and connect it to a spectrum analyzer;

[0020] B5. Set the amplitude parameter V1 and frequency parameter f of the signal source, record the spectrum analyzer receiving amplitude V2, adjust the frequency and repeat this step until all frequencies are tested;

[0021] B6. Without changing the layout of steps B2, B3 and B4, separate the semi-open cavity shell from the auxiliary test shielding chassis, and only retain the auxiliary test shielding chassis;

[0022] B7. Set the amplitude parameter V3 and frequency parameter f of the signal source, record the spectrum analyzer receiving amplitude V4, adjust the frequency and repeat this step until all frequencies are tested.

[0023] The calculation formula of the shielding effectiveness includes: P(f)=V1(f)-V2(f)-V3(f)+V4(f).

[0024] A shielding effectiveness test device for a semi-open cavity shell based on a shielding chassis, the device comprising an auxiliary test shielding chassis design module, a shielding effectiveness test module and a data processing and analysis module;

[0025] The auxiliary test shielding chassis design module is configured to design an auxiliary test shielding chassis matching the semi-open cavity shell according to the size and shape of the semi-open cavity shell;

[0026] The shielding effectiveness test module is configured to test the shielding effect of the semi-open cavity shell by a built-in radiation source method on the basis of auxiliary testing of the shielding chassis;

[0027] The data processing and analysis module is configured to process the signal source amplitude and the spectrum analyzer amplitude value at respective frequency points under two conditions: with a semi-open cavity shell and without a semi-open cavity shell, so as to obtain the shielding effectiveness of the semi-open cavity shell under the final set device state and position conditions.

[0028] The auxiliary test shielding chassis design module specifically includes the following contents:

[0029] A1. Design the auxiliary test shielding box as a cube or a cuboid with one face being a square face, and the side length of the square face is greater than 3 times the maximum size of the open face of the semi-open cavity shell to be tested, and the parameter of the other side of the cuboid is greater than the side length of the front face;

[0030] A2. In the center of the square surface, a matching assembly hole is opened according to the shape of the open surface of the semi-open cavity shell, and a flange device is set at the opened position;

[0031] A3. A test hole is opened in the center of the side of the assembly hole, and a matching buckled shielding cover is designed. The buckled shielding cover completely closes the test hole, and a through-cabin RF adapter is set in the buckled shielding cover;

[0032] A4. Inside the auxiliary test shielding chassis, a vertical support frame is set at the center of the square surface opposite to the assembly hole. The fixture of the small transmitting antenna and the near-field sensor is fixed at the top of the vertical support frame, and the overall height of the vertical support frame is adjusted to ensure that the small antenna and the near-field sensor can move vertically inside the semi-open cavity shell to be tested;

[0033] A5. High-frequency small absorbing spikes are arranged inside the five surfaces of the auxiliary test shielding chassis except the assembly hole surface to absorb the internal electromagnetic waves.

[0034] The shielding effectiveness test module specifically includes the following contents:

[0035] B1. Fix the semi-open cavity shell and the auxiliary test shielding chassis through the assembly holes, and the two together form an integral closed cavity;

[0036] B2. Fix a small transmitting antenna on the vertical bracket inside the auxiliary test shielding box. The transmitting antenna mouth faces outward through the test hole and is connected to the external signal source through the through-cabin RF adapter on the test hole via the RF line. Move the transmitting antenna inside the overall closed cavity by adjusting the vertical bracket.

[0037] B3. Calibrate the height of the vertical bracket to ensure that the small transmitting antenna is fixed in position;

[0038] B4. Set up a receiving antenna at the distance and angle set in the overall closed cavity and connect it to a spectrum analyzer;

[0039] B5. Set the amplitude parameter V1 and frequency parameter f of the signal source, record the spectrum analyzer receiving amplitude V2, adjust the frequency and repeat this step until all frequencies are tested;

[0040] B6. Without changing the layout of steps B2, B3 and B4, separate the semi-open cavity shell from the auxiliary test shielding chassis, and only retain the auxiliary test shielding chassis;

[0041] B7. Set the amplitude parameter V3 and frequency parameter f of the signal source, record the spectrum analyzer receiving amplitude V4, adjust the frequency and repeat this step until all frequencies are tested.

[0042] The present invention has the following advantages: a method and device for testing the shielding effectiveness of a semi-open cavity shell based on a shielded chassis, which solves the problem that the shielding effectiveness of a semi-open cavity shell is difficult to obtain, realizes the testing and evaluation of the shielding characteristics of the semi-open cavity shell, and provides a basis for the electromagnetic protection design of equipment inside the semi-open cavity shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a 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 drawings here can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present application provided below in conjunction with the drawings is not intended to limit the scope of protection of the application claimed for protection, but merely represents the 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 making creative work belong to the scope of protection of the present application. The present invention is further described below in conjunction with the drawings.

[0045] like Figure 1 As shown, the present invention specifically relates to a method for testing the shielding effectiveness of a semi-open cavity shell based on a shielded chassis, which specifically includes the following contents:

[0046] S1. Design of auxiliary test shielding chassis: According to the size and shape of the semi-open cavity shell, a matching auxiliary test shielding chassis is designed. The typical shape of the chassis is a cube or a rectangular parallelepiped (one of the faces is a square face).

[0047] (1) According to the 6-face division, the side length of the square face must be greater than 3 times the maximum size of the open face of the semi-open cavity shell to be tested; the other side length parameter of the cube or cuboid must not be less than the side length of the square face;

[0048] (2) In the center of the square surface in (1), an assembly hole matching the shape of the open surface of the semi-open cavity shell is opened, and a flange device (capable of matching and fixing the flange with the open surface of the semi-open cavity shell) is provided at the opening;

[0049] (3) A test hole is opened at the center of the side of the assembly hole in (2), and a matching buckle shielding cover is designed. The buckle shielding cover can completely close the test hole, and a through-cabin RF adapter is set in the buckle shielding cover;

[0050] (4) Inside the auxiliary test shielding chassis, a vertical support frame is provided at the center of the square surface directly opposite to the assembly hole in (2), and a clamp is provided at the top of the vertical support frame for fixing the small transmitting antenna and the near-field sensor. The overall height of the vertical support frame is adjustable (the adjustment range can ensure that the small antenna and the near-field sensor can move vertically inside the semi-open cavity shell to be tested);

[0051] (5) High-frequency small absorbing spikes are arranged on the five surfaces of the auxiliary test shielding chassis except the assembly hole surface to absorb the internal electromagnetic waves (reduce reflection).

[0052] S2. Shielding effectiveness data acquisition: Based on the auxiliary test of the shielded chassis, the shielding effectiveness of the semi-open cavity shell can be further tested by the built-in radiation source method. The steps are as follows:

[0053] (1) The semi-open cavity shell and the auxiliary test shielding chassis are fixed through the assembly holes, and the two together form an integral closed cavity;

[0054] (2) A small transmitting antenna (or a small near-field sensor as needed) is fixed on the vertical bracket inside the auxiliary test shielding box. The transmitting antenna faces outward through the test hole (toward the tested cavity) and is connected to the external signal source through the through-cabin RF adapter on the test hole via an RF line. The small transmitting antenna is moved inside the overall closed cavity by adjusting the vertical bracket;

[0055] (3) Calibrate the height of the vertical bracket to ensure that the small transmitting antenna is fixed in position (the specific position can be determined according to the height of the electronic equipment installed inside the semi-open cavity shell being tested);

[0056] (4) Setting a receiving antenna at a certain distance and angle from the overall closed cavity and connecting it to a spectrum analyzer;

[0057] (5) Set the amplitude parameter V1 and frequency parameter f of the signal source in (3), and record the spectrum analyzer receiving amplitude V2 in (4); adjust the frequency and repeat this step until all frequencies are tested;

[0058] (6) Without changing the layout of steps (2), (3), and (4), separate the semi-open cavity shell from the auxiliary test shielding chassis, and only retain the auxiliary test shielding chassis (at this time, all the settings in (2), (3), and (4) are unchanged relative to the auxiliary test shielding chassis);

[0059] (7) Set the amplitude parameter V3 and frequency parameter f of the signal source in (3), and record the spectrum analyzer receiving amplitude V4 in (4); adjust the frequency and repeat this step until all frequencies are tested.

[0060] S3. Shielding effectiveness data processing and analysis: In the two cases of having a semi-open cavity shell and not having a semi-open cavity shell, the signal source amplitude and spectrum analyzer amplitude values ​​at their respective frequencies are processed to obtain the shielding effectiveness of the semi-open cavity shell under the final set state and position conditions, as follows:

[0061] P(f)=V1(f)-V2(f)-V3(f)+V4(f)

[0062] When V1(f) and V3(f) are set to be the same, P(f)=V4(f)-V2(f).

[0063] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used for various other combinations, modifications and improvements, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for testing the shielding effectiveness of a semi-open cavity shell based on a shielded chassis, characterized in that: The test method includes: Step 1: design an auxiliary test shielding chassis matching the semi-open cavity shell according to the size and shape of the semi-open cavity shell; Step 2: On the basis of the auxiliary test shielding chassis, the shielding effect of the semi-open cavity shell is tested by the built-in radiation source method; Step 3: Under the two conditions of having a semi-open cavity shell and not having a semi-open cavity shell, the signal source amplitude and the spectrum analyzer amplitude value at each frequency point are processed to obtain the shielding effectiveness of the semi-open cavity shell under the final device state and position conditions.

2. The method for testing shielding effectiveness of a semi-open cavity shell based on a shielded chassis according to claim 1, characterized in that: The step 1 specifically includes the following contents: A1. Design the auxiliary test shielding box as a cube or a cuboid with one face being a square face, and the side length of the square face is greater than 3 times the maximum size of the open face of the semi-open cavity shell to be tested, and the parameter of the other side of the cuboid is greater than the side length of the front face; A2. In the center of the square surface, a matching assembly hole is opened according to the shape of the open surface of the semi-open cavity shell, and a flange device is set at the opened position; A3. A test hole is opened in the center of the side of the assembly hole, and a matching buckled shielding cover is designed. The buckled shielding cover completely closes the test hole, and a through-cabin RF adapter is set in the buckled shielding cover; A4. Inside the auxiliary test shielding chassis, a vertical support frame is set at the center of the square surface opposite to the assembly hole. The fixture of the small transmitting antenna and the near-field sensor is fixed at the top of the vertical support frame, and the overall height of the vertical support frame is adjusted to ensure that the small antenna and the near-field sensor can move vertically inside the semi-open cavity shell to be tested; A5. High-frequency small absorbing spikes are arranged inside the five surfaces of the auxiliary test shielding chassis except the assembly hole surface to absorb the internal electromagnetic waves.

3. The method for testing shielding effectiveness of a semi-open cavity shell based on a shielded chassis according to claim 1, characterized in that: The step 2 specifically includes the following contents: B1. Fix the semi-open cavity shell and the auxiliary test shielding chassis through the assembly holes, and the two together form an integral closed cavity; B2. Fix a small transmitting antenna on the vertical bracket inside the auxiliary test shielding box. The transmitting antenna mouth faces outward through the test hole and is connected to the external signal source through the through-cabin RF adapter on the test hole via the RF line. Move the transmitting antenna inside the overall closed cavity by adjusting the vertical bracket. B3. Calibrate the height of the vertical bracket to ensure that the small transmitting antenna is fixed in position; B4. Set up a receiving antenna at the distance and angle set in the overall closed cavity and connect it to a spectrum analyzer; B5. Set the amplitude parameter V1 and frequency parameter f of the signal source, record the spectrum analyzer receiving amplitude V2, adjust the frequency and repeat this step until all frequencies are tested; B6. Without changing the layout of steps B2, B3 and B4, separate the semi-open cavity shell from the auxiliary test shielding chassis, and only retain the auxiliary test shielding chassis; B7. Set the amplitude parameter V3 and frequency parameter f of the signal source, record the spectrum analyzer receiving amplitude V4, adjust the frequency and repeat this step until all frequencies are tested.

4. The method for testing shielding effectiveness of a semi-open cavity shell based on a shielded chassis according to claim 3 is characterized in that: The calculation formula of the shielding effectiveness includes: P(f)=V1(f)-V2(f)-V3(f)+V4(f).

5. A shielding effectiveness test device for a semi-open cavity shell based on a shielded chassis, characterized in that: The device includes an auxiliary test shielding chassis design module, a shielding effectiveness test module and a data processing and analysis module; The auxiliary test shielding chassis design module is configured to design an auxiliary test shielding chassis matching the semi-open cavity shell according to the size and shape of the semi-open cavity shell; The shielding effectiveness test module is configured to test the shielding effect of the semi-open cavity shell by a built-in radiation source method on the basis of auxiliary testing of the shielding chassis; The data processing and analysis module is configured to process the signal source amplitude and the spectrum analyzer amplitude value at respective frequency points under two conditions: with a semi-open cavity shell and without a semi-open cavity shell, so as to obtain the shielding effectiveness of the semi-open cavity shell under the final set device state and position conditions.

6. The shielding effectiveness test device of a semi-open cavity shell based on a shielded chassis according to claim 5, characterized in that: The auxiliary test shielding chassis design module specifically includes the following contents: A1. Design the auxiliary test shielding box as a cube or a cuboid with one face being a square face, and the side length of the square face is greater than 3 times the maximum size of the open face of the semi-open cavity shell to be tested, and the parameter of the other side of the cuboid is greater than the side length of the front face; A2. In the center of the square surface, a matching assembly hole is opened according to the shape of the open surface of the semi-open cavity shell, and a flange device is set at the opened position; A3. A test hole is opened in the center of the side of the assembly hole, and a matching buckled shielding cover is designed. The buckled shielding cover completely closes the test hole, and a through-cabin RF adapter is set in the buckled shielding cover; A4. Inside the auxiliary test shielding chassis, a vertical support frame is set at the center of the square surface opposite to the assembly hole. The fixture of the small transmitting antenna and the near-field sensor is fixed at the top of the vertical support frame, and the overall height of the vertical support frame is adjusted to ensure that the small antenna and the near-field sensor can move vertically inside the semi-open cavity shell to be tested; A5. High-frequency small absorbing spikes are arranged inside the five surfaces of the auxiliary test shielding chassis except the assembly hole surface to absorb the internal electromagnetic waves.

7. The shielding effectiveness test device of a semi-open cavity shell based on a shielded chassis according to claim 5, characterized in that: The shielding effectiveness test module specifically includes the following contents: B1. Fix the semi-open cavity shell and the auxiliary test shielding chassis through the assembly holes, and the two together form an integral closed cavity; B2. Fix a small transmitting antenna on the vertical bracket inside the auxiliary test shielding box. The transmitting antenna mouth faces outward through the test hole and is connected to the external signal source through the through-cabin RF adapter on the test hole via the RF line. Move the transmitting antenna inside the overall closed cavity by adjusting the vertical bracket. B3. Calibrate the height of the vertical bracket to ensure that the small transmitting antenna is fixed in position; B4. Set up a receiving antenna at the distance and angle set in the overall closed cavity and connect it to a spectrum analyzer; B5. Set the amplitude parameter V1 and frequency parameter f of the signal source, record the spectrum analyzer receiving amplitude V2, adjust the frequency and repeat this step until all frequencies are tested; B6. Without changing the layout of steps B2, B3 and B4, separate the semi-open cavity shell from the auxiliary test shielding chassis, and only retain the auxiliary test shielding chassis; B7. Set the amplitude parameter V3 and frequency parameter f of the signal source, record the spectrum analyzer receiving amplitude V4, adjust the frequency and repeat this step until all frequencies are tested.

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