KR102576796B1 - System for measuring electromagnetic shielding effectiveness - Google Patents

Abstract

An electromagnetic wave shielding performance measuring device according to one aspect of the present invention includes an electromagnetic wave transmitting unit that generates electromagnetic waves; An electromagnetic wave receiving unit that receives and measures the electromagnetic waves; a plate provided between the electromagnetic wave transmitting unit and the electromagnetic wave receiving unit and including an opening therein; a sample support unit provided at a front side of the plate on the electromagnetic wave transmitting unit side and including a stand on which a measurement sample is placed; A first frame coupled to the front of the plate with a support and movable along the support, a sample holding portion coupled to the first frame in the direction of the plate and including an adhesion member in contact with the measurement sample, The first frame and the adhesion member are characterized in that they include a material having a relative dielectric constant of 3.5 to 4.0.

Description

Electromagnetic shielding performance measurement system {System for measuring electromagnetic shielding effectiveness}

One aspect of the present invention relates to an electromagnetic wave shielding performance measuring device, and more specifically, to an electromagnetic wave shielding performance measuring device capable of measuring the electromagnetic wave shielding rate of building materials such as concrete.

Herein, background technology regarding the present disclosure is provided, and does not necessarily mean that it is well-known technology.

In general, an electromagnetic pulse (EMP) is an electromagnetic shock wave generated by a nuclear explosion. It generates an electric field of approximately 50 kV/m and a very large electromagnetic energy of 5000 A without directly causing damage to people or buildings. It is induced through power lines and communication lines or applied directly to devices, destroying electronic circuits and instantly paralyzing all electronic devices that operate on semiconductors, such as military equipment, communication equipment, computers, means of transportation, computer networks, etc., in nanoseconds. Recently, it is possible to destroy the enemy's industrial facilities while avoiding international condemnation for killing people, and as modern warfare is waged by communication and weapons systems based on the electronics industry, the enemy's military communications without damaging people and buildings. ·EMP bombs that can neutralize all power systems, including weapons systems, and countermeasures against enemy countries' nuclear development and high-altitude nuclear tests and attacks are required.

As a countermeasure technology to prevent electromagnetic interference, various methods such as filtering, shielding, wiring, and grounding are used, and among these, the shielding method is used to reduce the resistance of devices or structures. This is a method that can be used appropriately when considering the aspects.

Therefore, in order to develop materials with excellent shielding performance, accurate shielding performance analysis must be conducted first. For materials that have the function of shielding electromagnetic waves, the existing measurement method used to evaluate the shielding performance involves manufacturing the material in the form of a structure that is actually used and measuring the characteristics. This measurement method measures by installing an antenna inside a structure and radiating electromagnetic waves, thereby detecting electromagnetic waves leaking through the wall of the structure using an antenna or probe.

This measurement method has the advantage of obtaining measurement results that are closest to the actual situation because it approximates the structure that is ultimately created using the material to be evaluated, but it also has the advantage of obtaining measurement results that are closest to the actual situation. Because electromagnetic wave shielding characteristics are greatly affected by structural characteristics, etc., it is difficult to see the characteristics of the material itself.

In addition, when measuring the electromagnetic shielding rate using a conventional measurement method, the thickness of the sample must be limited to 2 mm or less when measuring the electromagnetic shielding rate using the ASTM D4935 method, making it difficult to make or measure the sample with materials such as concrete. .

In particular, when using the test device of Republic of Korea Patent No. 10-2085038, the present applicant discovered that the amplitude value of the electromagnetic wave decreased for electromagnetic waves in the area with a frequency near 1 GHz, thereby reducing the dynamic range, which is the main performance indicator of the test device. As a result, it became impossible to measure high shielding rates near 1 GHz. In addition, the problem of low reliability of electromagnetic shielding rates measured in the 30 MHz to 1.5 GHz range, which is the measurement frequency range of ASTM D 4935, was identified, and this phenomenon was identified. Efforts have been made to develop an electromagnetic shielding rate measurement system that can measure electromagnetic shielding performance with constant intensity and high reliability in the frequency range of 30 MHz to 1.5 GHz.

Republic of Korea Patent No. 10-2085038

The purpose of the present invention is to solve the problems of the prior art described above, and to provide a highly reliable electromagnetic shielding rate measurement system that can measure electromagnetic waves of stable intensity in the frequency range of 300 MHz to 1.5 GHz. There is a purpose.

In addition, the electromagnetic shielding rate measurement system of the present invention aims to provide an electromagnetic shielding rate measurement device that facilitates measurement of electromagnetic shielding performance of a measurement sample made of electromagnetic shielding concrete material and an electromagnetic wave shielding rate measurement system utilizing the same.

In addition, we aim to provide an electromagnetic shielding rate measurement device that is convenient for transporting and fixing heavy measurement samples and is easy to operate during experiments.

One aspect of the present invention is an electromagnetic wave transmitting unit installed in the front and generating electromagnetic waves;

An electromagnetic wave receiving unit that receives and measures the electromagnetic waves;

a plate provided between the electromagnetic wave transmitting unit and the electromagnetic wave receiving unit and including an opening therein; a sample support unit provided in front of the plate and including a stand on which a measurement sample is placed;

A first frame coupled to a support provided in front of the plate and movable along the support, a sample holding portion coupled to the rear of the first frame and including an adhesion member in contact with the measurement sample,

The first frame and the adhesion member are electromagnetic wave shielding performance measuring devices made of a material with a relative dielectric constant of 3.5 to 4.0.

Here, the first frame is preferably made of phenolic resin,

The adhesion member is preferably made of polyacetal,

The first frame preferably includes an opening provided at a position where the measurement sample is fixed.

At this time, it is preferable to include a second frame coupled to the support in front of the first frame and including an opening in the center,

The electromagnetic wave receiving unit is provided inside, and preferably includes an electromagnetic wave shielding room including an electromagnetic wave shielding wall,

It is preferable that the plate is coupled to the front of the electromagnetic wave shielding wall.

In addition, the opening width (W2) of the second frame is preferably 1.0 to 1.5 times the opening width (W1) of the first frame,

The adhesion member is preferably coupled to surround the outside of the opening of the first frame,

It is preferable to include a space surrounded by the first frame, the measurement sample, and the adhesion member.

Another aspect of the present invention is an electromagnetic wave shielding performance measurement system that measures the electromagnetic wave shielding performance of the measurement sample by receiving electromagnetic waves radiated from the electromagnetic wave transmitter and passing through the measurement sample at the electromagnetic wave receiver,

an electromagnetic wave shielding room including an electromagnetic wave shielding wall in which the electromagnetic wave receiving unit is provided and an opening in the direction of the electromagnetic wave transmitting unit;

a sample support portion coupled to the electromagnetic wave shielding wall and supporting the measurement sample; and

A first frame coupled to a support in front of the sample support and movable along the support, a sample holding portion including a close contact member coupled to the first frame and in contact with the measurement sample,

The first frame and the adhesion member are electromagnetic wave shielding performance measurement systems that include synthetic resin as a material.

At this time, the electromagnetic wave transmitting unit preferably radiates electromagnetic waves in a frequency range including 30 MHz to 1.5 GHz.

The electromagnetic shielding rate measuring device according to one aspect of the present invention is made of a synthetic resin material such as Bakelite, fixes the electromagnetic shielding rate measurement sample using a frame provided with an opening, and electromagnetic wave shielding rate measurement sample is transmitted through the opening provided in the frame. By radiating and transmitting the measurement sample, it is possible to solve the problem of the electromagnetic wave intensity measurement value rapidly decreasing in the frequency range of 1 GHz, thereby measuring electromagnetic waves of uniform intensity, and excellent reliability can be secured in the range of 30 MHz to 1.5 GHz.

In addition, the electromagnetic wave shielding rate measuring device is equipped with an adhesion member 42 made of a synthetic resin material such as polyacetal to maintain the distance between the first frame 41 and the measurement sample at a constant interval and to close the opening of the first frame 41. By minimizing the influence of electromagnetic waves incident on the measurement sample, such as reflection, it has the effect of providing excellent reliability and reducing errors in experimental data.

The electromagnetic shielding performance measurement system according to one aspect of the present invention uses an electromagnetic shielding rate measuring device that has the above effects, and measures the electromagnetic shielding rate of materials such as concrete that are difficult to measure using existing electromagnetic shielding rate measurement methods with high reliability. There are advantages to doing this.

Figure 1 is a diagram showing the schematic configuration of an electromagnetic wave shielding performance measuring device, which is one aspect of the present invention.
Figure 2 is a diagram schematically showing the configuration of an electromagnetic wave shielding performance measuring device, which is one aspect of the present invention.
Figure 3 is a view showing the electromagnetic wave shielding performance measuring device, which is one aspect of the present invention, as seen from the front.
Figure 4 is a diagram schematically showing the appearance of an electromagnetic wave shielding performance measuring device, which is one aspect of the present invention.
Figure 5 is a side view showing a state in which a measurement sample is fixed to an electromagnetic wave shielding performance measuring device, which is one aspect of the present invention.
Figure 6 is a side view showing a state in which a measurement sample is not fixed to the electromagnetic wave shielding performance measuring device, which is one aspect of the present invention.
Figure 7 is a graph showing the intensity of electromagnetic waves measured according to frequency when an existing metal jig is used as a frame.
Figure 8 is a graph showing the intensity of electromagnetic waves measured according to frequency after changing the frame material to synthetic resin.
Figure 9 is a graph showing the intensity of electromagnetic waves measured by using different frame materials such as metal and bakelite.
Figure 10 is a diagram schematically showing another aspect of the electromagnetic wave shielding performance measurement system of the present invention.

Before describing the present invention in detail below, it is understood that the terms used in this specification are only for describing specific embodiments and are not intended to limit the scope of the present invention, which is limited only by the appended claims. shall. All technical and scientific terms used in this specification have the same meaning as generally understood by those skilled in the art, unless otherwise specified.

Throughout this specification and claims, unless otherwise stated, the terms comprise, comprises, and comprise mean to include the mentioned article, step, or group of articles, and steps, and any other article. , it is not used in the sense of excluding a step, a group of objects, or a group of steps.

Meanwhile, various embodiments of the present invention may be combined with any other embodiments unless clearly indicated to the contrary. Any feature indicated as being particularly preferred or advantageous may be combined with any other feature or feature indicated as being preferred or advantageous.

In the drawings, the width, length, thickness, etc. of components may be exaggerated for convenience. When explaining the drawing as a whole, it is explained from the observer's point of view, and when one component is said to be "above/below" or "above/below" another component, this is not only the case where it is "directly above/immediately below" the other component. , also includes cases where there is another component in between.

The electromagnetic shielding performance measuring device according to one aspect of the present invention can be used for samples of various sizes, especially those that are thick or large in size, and for which measurement was limited by the ASTM D4935 method, which was used as a conventional electromagnetic shielding performance measurement method. It is a device.

The measurement sample (1) used at this time is manufactured in a size and shape suitable for measurement. The shape of the measurement sample (1) is preferably a rectangular parallelepiped with a flat surface, and is flat and has a relatively thick thickness compared to the height and width. It is desirable to use thin specimens.

1 and 2 are diagrams schematically showing an electromagnetic wave shielding performance measurement device and system, which is one aspect of the present invention.

The electromagnetic wave shielding performance measuring device includes an electromagnetic wave transmitting unit 10 including a transmission antenna that radiates electromagnetic waves to the outside, an electromagnetic wave receiving unit 20 including a receiving antenna that receives electromagnetic waves radiated from the electromagnetic wave transmitting unit 10, and an electromagnetic wave transmitting unit 10. ) and the electromagnetic wave receiver 20, so that the measurement sample 1 can be provided between the sample support 30 and the sample support 30, which supports the measurement sample 1, and measures the measurement sample 1. It includes a sample fixing part 40 that is fixed in a position for.

In addition, the electromagnetic wave shielding performance measuring device preferably includes an electromagnetic wave shielding room containing a receiving antenna therein, as shown in FIGS. 1 and 2.

The electromagnetic wave shielding room 50 is intended to reflect or absorb electromagnetic waves to create a first space that is unaffected or less affected by electromagnetic waves from the outside, and includes at least one electromagnetic wave shielding wall capable of shielding electromagnetic waves.

The electromagnetic wave shield room contains a receiving antenna inside, and the electromagnetic wave inside the wall is designed to minimize measurement errors that occur when external electromagnetic waves are transmitted into the electromagnetic wave shield room or transmitted to the receiving antenna by reflection of electromagnetic waves inside the electromagnetic wave shield room. It is desirable to have an absorber and may include a stirrer.

Electromagnetic wave absorbers can be used in both conical and pyramidal shapes, and any electromagnetic wave absorber that can be generally employed in the relevant technical field can be used regardless of its shape or material.

The electromagnetic wave shielding room 50 is intended to reflect or absorb electromagnetic waves to create a first space that is unaffected or less affected by electromagnetic waves from the outside, and includes at least one electromagnetic wave shielding wall capable of shielding electromagnetic waves.

The electromagnetic wave shielding wall 51 can be used to separate two spaces, the first space and the second space.

The first space is a space where the receiving antenna of the electromagnetic wave receiving unit is installed or provided, and the electromagnetic waves generated in the second space are shielded by the electromagnetic wave shielding wall 51 to prevent them from being transmitted to the first space.

The second space is a space where the transmission antenna of the electromagnetic wave transmission unit is installed or provided.

The electromagnetic wave shielding wall may include an opening through which electromagnetic waves can pass. The opening is provided in the electromagnetic wave shielding wall, but electromagnetic waves can pass through the opening without being shielded.

The first space and the second space can be connected through an opening provided in the electromagnetic wave shielding wall, and electromagnetic waves emitted from the transmitting antenna installed in the second space are transmitted directly to the receiving antenna installed in the first space in an unshielded state through the opening. It can be delivered. At this time, the electromagnetic wave shielding effect that occurs when the shield blocks or covers the opening can be calculated based on the intensity of the electromagnetic wave measured without the shield through the opening.

The size of the opening provided in the electromagnetic wave shielding wall is not limited, but the width or width (W) is preferably 20 to 30 cm. If the width or height of the opening is larger than the corresponding range and the size of the measurement sample (1) to shield the opening becomes too large, the weight increases according to the volume and the measurement sample (1) cannot be supported stably, reducing the size of the measurement device. There is a problem of increasing production costs because it has to be large, and it is difficult to transport or fix the measurement sample (1), and if the width or height of the opening is smaller than the corresponding range, the wavelength of electromagnetic waves that can be measured for electromagnetic shielding rate is limited. As the frequency range becomes narrower, there may be a problem of lower usability.

Specifically, the width (W) of the opening must be at least half the wavelength (λ/2) of the wavelength (λ) corresponding to the frequency of the electromagnetic wave to be measured, and is configured to satisfy the following formula (1).

(Equation 1)

The electromagnetic wave shielding room 50 is not necessarily required to be a space isolated or separated from the outside, and can be a space with at least one side open as long as the electromagnetic wave shielding wall 51 is large enough so that electromagnetic waves do not affect it.

For example, when measuring shielding performance against electromagnetic waves with a frequency of 600 MHz, the width (or height) of the opening is configured to be 0.25 m or more. Due to the nature of electromagnetic waves, in a space made of metal, the opening acts like a waveguide and can block or pass specific frequencies. At this time, the frequency of the electromagnetic wave that can pass through the opening is determined by the width of the opening, and if the width and the wavelength of the electromagnetic wave are equal to or 0.5 times greater, the frequency is allowed to pass. Resonance occurs when the width of the opening is 3λ, 2λ, λ, 1/2λ, 1/4λ, 1/8λ, etc., and the resonance effect is especially large at λ and 1/2λ. Therefore, if an opening is provided that is narrower than a half-wavelength of the wavelength corresponding to the frequency, that is, if Equation 1 above is not satisfied, electromagnetic waves are blocked and the electromagnetic wave shielding performance cannot be measured.

The electromagnetic wave transmitting unit 10 includes an electromagnetic wave generator and a transmission antenna, and electromagnetic waves generated at a desired frequency by the electromagnetic wave generator can be radiated to the outside through the transmission antenna.

Various types and types of transmission antennas may be used, but it is preferable to use a log periodic antenna (LP antenna).

The transmitting antenna can be installed using a tripod, etc., and is preferably installed at a height similar to the opening provided in the electromagnetic wave shielding wall.

The transmission antenna can be installed in the vertical or horizontal direction depending on the installation direction, and can be freely switched between the vertical and horizontal directions.

The transmission antenna should preferably be capable of emitting electromagnetic waves with a frequency ranging from 30 MHz to 1.5 GHz, and its size is not limited.

The electromagnetic wave receiving unit 20 includes a receiver and a receiving antenna, and receives electromagnetic waves generated and radiated by the electromagnetic wave transmitting unit 10 to the receiver through the receiving antenna.

The antenna is characterized by being able to perform both roles without distinguishing between transmission and reception for radio waves of the appropriate frequency, and is provided as a pair.

In other words, when one antenna is used as a transmitting antenna, the other antenna can be used as a receiving antenna, and it is preferable that the transmitting antenna and the receiving antenna have the same structure.

It is preferable that the receiving antenna is installed at the same height as the transmitting antenna, and that an opening in the electromagnetic wave shielding wall is provided between the transmitting antenna and the receiving antenna.

The electromagnetic shielding performance measuring device is configured to support and fix the measurement sample (1), which is the object of measuring the electromagnetic wave shielding rate, and reduce loss or error in the process of electromagnetic waves penetrating the measurement sample (1), and includes a sample support portion (30). and a sample fixing unit (40).

Figure 3 is a diagram schematically showing the sample fixing part 40 and the sample support part 30 as seen from the front.

The sample support portion 30 serves to support the measurement sample 1 for measuring electromagnetic wave shielding ability at the measurement position and includes a plate 31, a stand 32, and a gasket 33.

The plate 31 is coupled around the opening of the electromagnetic wave shielding wall and includes an opening through which electromagnetic waves can pass. The plate 31 may be made of a metal material that does not transmit electromagnetic waves and reflects electromagnetic waves from its surface.

The plate 31 is located between the electromagnetic wave transmitting unit 10 and the electromagnetic wave receiving unit 20. Hereinafter, the direction of the electromagnetic wave transmitting unit 10 is toward the front of the plate 31, and the direction of the electromagnetic wave receiving section 20 is toward the side of the plate 31. Defined as rear.

The stand 32 serves to support the lower part of the measurement sample 1 so that the measurement sample 1 can be positioned at a position corresponding to the opening of the plate 31. Its shape is not limited, but its length in the horizontal direction is not limited. It is preferable to have a rectangular parallelepiped structure.

The pedestal 32 is preferably made of a material that has a strong property of transmitting electromagnetic waves and has a low property of reflecting electromagnetic waves on the surface. For example, it is better to use a synthetic resin material. An embodiment of the present invention is a pedestal ( 32), polyacetal material is used.

The stand 32 is located at the lower part of the opening of the plate 31 and is coupled to the plate 31 so that the measurement sample 1 placed on the stand 32 covers or coincides with the opening of the plate 31. It is installed on the front side, that is, from the plate 31 toward the electromagnetic wave transmitting unit 10.

Figure 4 is a view showing the appearance of the sample fixing part 40 and the sample support part 30. The stand 32 may be provided to extend long to one side when viewed from the front, as shown in FIG. 3, and may be provided with a bearing 46 on the bottom to facilitate the user moving or adjusting the position of the measurement sample 1. You can.

The measurement sample 1 placed on the pedestal 32 by the bearing 46 can be easily moved on the pedestal 32.

In addition, the gasket 33 is provided at the portion where the outer edge of the opening of the plate 31 is in contact with the measurement sample (1) to provide closer contact between the measurement sample (1) and the plate (31) and penetrates the measurement sample (1). It prevents electromagnetic waves from being lost through the gap between the plate 31 and the measurement sample 1 or causing errors, enabling highly reliable measurements.

The sample support unit 30 may additionally include a panel 34, and the panel 34 is installed between the plate 31 and the electromagnetic wave shielding wall to facilitate attachment and detachment of the sample support unit 30 and the electromagnetic wave shielding wall. You can.

At this time, the panel 34 is optionally installed between the plate 31 and the electromagnetic wave shielding wall, and similarly includes an opening at a position corresponding to the opening provided in the plate 31 and the electromagnetic wave shielding wall.

The sample support unit 30 coupled to the electromagnetic wave shielding wall includes an opening at the same position as the opening of the electromagnetic wave shielding wall, and includes a hole connecting the outside and the inside of the electromagnetic wave shielding room. At this time, the shape of the opening provided in the electromagnetic wave shielding wall and the sample support unit 30 coupled thereto is not limited, but is preferably rectangular or square, and the width or breadth of the opening can be defined as W0.

A measurement sample 1 having an area equal to or greater than the area of the opening can be placed in front of the opening by the sample support unit 30. The arranged measurement sample (1) is placed on the stand (32) to cover the opening, and is preferably placed so as to completely cover the opening when viewed from the front.

The sample fixing part 40 is a means of fixing the measurement sample 1 supported on the sample support part 30, and is coupled to the support 44 in a state of being coupled to the sample support part 30, so that the length of the support 44 is It includes a first frame 41 that can move in any direction and serves to adhere the measurement sample 1 to the sample support 30 according to the movement of the frame.

The sample holding part 40 includes a first frame 41, a second frame 43, and an adhesion member 42.

The first frame 41 is coupled to the front side of the plate 31 with a support 44, and preferably has a ring shape including an opening in the center that is smaller or the same size as that of the measurement sample 1. In one embodiment of the present invention, the first frame 41, which includes a square-shaped exterior and a square-shaped opening on the inside, is coupled with four supports 44 near each vertex, and the portion coupled with the supports 44 It has a structure that allows movement in the longitudinal direction of the support 44 along the support 44 by manipulating the distance adjustment screw 45 located in the middle of .

Figures 5 and 6 are views showing the sample support portion 30 and the sample fixing portion 40 as viewed from the side. Figure 5 shows a state in which the first frame 41 is moved in the direction of the measurement sample 1 and is in close contact with the measurement sample 1, thereby fixing the measurement sample 1, and Figure 6 shows the first frame 41 in the measurement sample 1. This indicates that the measurement sample (1) is not fixed as it is moved in the opposite direction of the sample (1).

When the first frame (41) is moved in the direction of the measurement sample (1), it is in close contact with the measurement sample (1) and can fix the measurement sample (1), and when it is moved in the opposite direction to the measurement sample (1), the measurement sample (1) can be fixed. 1), the measurement sample (1) can be moved or replaced.

The width of the opening provided at the inner center of the first frame 41 can be defined as W1, and W1 is smaller than the width of the measurement sample 1.

In addition, the first frame 41 may be made of synthetic resin or reinforced plastic material, for example, it may include one or more of phenolic resin (including novolak resin and resol resin) and polyacetal resin. , Preferably, a phenolic resin containing a fabric such as cloth inside, for example, forbakrite, is used.

Phenolic resins have a smaller specific gravity than metals, but have excellent mechanical strength, resistance to heat, and good electrical properties and processability.

In particular, since it has high electrical insulation and low electromagnetic wave absorption rate, it has the advantage of having very little effect on the results of electromagnetic wave-related tests. It has excellent properties of absorbing electromagnetic waves without reflecting them from the surface or causing disturbance (disturbance), so it is suitable for use as the first frame 41 and can improve the reliability of electromagnetic wave shielding rate measurement experiments.

The phenolic resin preferably has a relative dielectric constant of 3.5 to 4.5, preferably 3.5 to 4.0. More specifically, the phenolic resin preferably has a relative dielectric constant of 3.5 to 4.5 at 3 GHz and 3.5 to 4.0 at 10 GHz.

If the relative dielectric constant of the phenolic resin is greater than 4.5, absorption or reflection of electromagnetic waves may occur, which reduces the reliability of the electromagnetic wave shielding ratio measurement data.

Hereinafter, when the term dielectric constant of a material is used in this specification, it is used to include relative permittivity, which means the dielectric constant of the dielectric when the dielectric constant of vacuum is set to 1.

The second frame 43 is provided in front of the first frame 41 and coupled to the support 44, and preferably has a ring shape including an opening in the center that is smaller or the same size as the measurement sample 1.

In one embodiment of the present invention, the second frame 43, which includes a square-shaped exterior and a square-shaped opening on the inside, is coupled with four supports 44 near each vertex, and the portion coupled with the supports 44 The first frame 41 has a structure that can be moved according to the operation of the distance adjustment screw 45 located in the middle.

The width of the opening provided at the inner center of the second frame 43 can be defined as W2. W2 is preferably larger than W1, and the ratio is 1 to 1.5 times, preferably 1 to 1.1 times. .

If the ratio of W2 and W1 is smaller than the corresponding range, W2 becomes smaller, making it difficult for the user to check the position and movement state of the first frame 41 when manipulating the distance adjustment screw 45, and the transmitted electromagnetic wave Incident conditions may become unfavorable, and if the ratio of W2 and W1 is greater than the corresponding range, economic feasibility may decrease and W1 may become small, which may limit the wavelength of electromagnetic waves that can be measured.

More specifically, W2 and W1 must be designed to be larger than the opening of the wall, and by providing W2 larger than W1, the input environment for electromagnetic waves can be improved. However, if the ratio is designed to exceed 1.1 times, the second frame 43 occupies too large a space, but there is a limit in which additional beneficial effects do not occur.

The second frame 43 is preferably made of a synthetic resin material, and is preferably made of the same phenolic resin as the first frame 41.

The adhesion member 42 is coupled to the rear surface of the first frame 41, that is, the surface on the measurement sample 1 side of the first frame 41, and is connected to the measurement sample 1 and the measurement sample 1 according to the movement of the first frame 41. It contacts and plays the role of fixing the measurement sample (1).

The adhesion member 42 is preferably made in the shape of a rectangular parallelepiped and can be fastened to the first frame 41 using screws.

The adhesion member 42 is preferably coupled to surround the opening provided inside the first frame 41, and in a preferred embodiment of the present invention, four adhesion members 42 are formed around the square-shaped opening. They are joined by surrounding them in an enclosing array.

The thickness of the adhesion member 42 varies, and it is possible for the adhesion member 42 to be combined in two or more layers. Depending on the thickness of the adhesion member 42 and the number of adhesion members 42 coupled to the first frame 41, when the adhesion member 42 is in close contact with the measurement sample 1, the first frame 41 and the measurement sample ( 1) The distance between them can be adjusted, for example, at intervals of 5 cm, 10 cm, 15 cm or 20 cm, and the distance between the adhesion member 42 and the measurement sample 1 is within 2 cm, preferably It is desirable to be within 1cm.

If the surface of the first frame (41) and the measurement sample (1) are too close, problems may arise in which smooth work cannot be performed due to narrow space when moving a heavy sample to the installation location, and if it is too far away, the sample's movement range may occur. As the sample increases, problems with worker safety may arise due to falling samples.

The adhesion member 42 is preferably made of synthetic resin, for example, polyacetal resin.

Polyacetal material has excellent mechanical properties, fatigue resistance, and chemical resistance, has a small coefficient of friction, and is resistant to wear. It is used in various machine parts and electrical parts, and has excellent electromagnetic wave transmission properties, blocking radiated electromagnetic waves. By not reflecting, measurement errors can be reduced.

When the adhesion member 42 and the measurement sample 1 are in close contact with each other, a separation space surrounded by the adhesion member 42 is provided between the surface of the measurement sample 1 and the rear surface of the first frame 41. Electromagnetic waves transmitted through the opening of frame 1 (41) pass through the separation space and pass through the measurement sample (1) through the incident surface of the measurement sample (1).

At this time, the adhesion member 42 surrounding the side of the first space is preferably made of synthetic resin or reinforced plastic material, for example, polyacetal.

The adhesion member 42 is preferably made of a material with a relative dielectric constant of 3.5 to 4.0, preferably 3.6 to 3.9. If the relative dielectric constant of the adhesion member 42 is outside the range, the reliability of the electromagnetic wave shielding rate measurement decreases. It can be.

Figures 7 and 8 show the frequency of electromagnetic waves with the direction of the antenna in the vertical and horizontal directions while the materials of the first frame 41 and the second frame 43 expressed as a jig are different from bakelite and metal. This is a graph showing the intensity of electromagnetic waves measured from the receiving antenna while changing .

Figure 9 is a graph showing the intensity of electromagnetic waves measured using a frame made of metal and a frame made of synthetic resin in the range of 600 MHz to 2 GHz.

When using the first and second frames 43 made of a metal material, a sharp decrease in the intensity of electromagnetic waves (y-axis) was observed in the area near 1 GHz, and the first and second frames 43 made of a synthetic resin bakelite material were observed. When using 2 frames (43), the above phenomenon did not occur in the area near 1 GHz, and a sharp decrease in the intensity of electromagnetic waves was observed in the area near 1.6 GHz.

In the ATSM D 4935 test method, the standard frequency range for measuring electromagnetic wave shielding rate and electromagnetic wave shielding performance is in the range of 30 MHz to 1.5 GHz, so when using the first and second frames 43 made of metal, the frequency range observed in the 1 GHz range is There is a problem that the reliability of the measured electromagnetic wave intensity and electromagnetic wave shielding rate data is reduced due to the phenomenon of electromagnetic wave intensity reduction, but when using the first and second frames 43 made of synthetic resin, the electromagnetic wave in the frequency range within 1.5 GHz is reduced. Since no decrease in intensity is observed, data reliability for electromagnetic shielding performance tests is improved.

In addition, one embodiment of the present invention uses a measurement sample 1 whose sides are surrounded by metal tape. Since a foam gasket is provided along the side of the measurement sample (1), the incident occurs through the entrance surface provided in the front of the measurement sample (1) and then exits from the inside of the measurement sample (1) to the side of the measurement sample (1). The foam gasket blocks electromagnetic waves and blocks electromagnetic waves coming into the measurement sample (1) from external diffuse reflections, allowing measurement of electromagnetic waves purely entering the concrete, reducing measurement errors and improving reliability.

The electromagnetic wave shielding performance measurement system according to another aspect of the present invention is a system including an electromagnetic wave shielding performance measurement device that measures the electromagnetic wave shielding performance, for example, the electromagnetic wave shielding rate, of the target material or measurement sample (1) made of the material. am.

Figure 10 is a diagram schematically showing the electromagnetic wave shielding performance measurement system.

The electromagnetic wave shielding performance measurement system generates electromagnetic waves using a signal generator that generates electromagnetic waves according to a pre-input frequency and a transmission antenna that amplifies and radiates the signal, and the radiated electromagnetic waves are transmitted to a fixed electromagnetic wave shielding performance measurement sample. It propagates to the incident surface of (1).

Electromagnetic waves penetrate the inside of the measurement sample (1) except for the part that is reflected from the incident surface of the measurement sample (1), and exit through the transmission surface located on the opposite side of the incident surface. At this time, the incident electromagnetic waves pass through the incident surface and the transmission surface. The intensity is reduced by reflection from the surface or absorption from the inside of the sample.

Electromagnetic waves that escape the penetrating surface travel through the air and are received by a receiving antenna. The receiving unit and control PC detect the signal, measure and record the intensity of the transmitted wave, and convert it into data.

The intensity of the electromagnetic wave measured by penetrating the sample can be expressed as EUT (Equipment under test). By removing the measurement sample (1), it is propagated into the air under the same frequency conditions and the intensity of the electromagnetic wave measured at the receiving antenna and receiver is REF ( Reference), REF-EUT, which is the difference between EUT and REF, can be called SE (Shielding effectiveness).

A preferred embodiment of the present invention is a device for supporting and fixing a measurement sample (1), including the sample support portion (30) and the sample fixation portion (40) of the electromagnetic wave shielding performance test device described above, and a device that supports and fixes a measurement sample (1), including the sample support portion (30) and sample fixation portion (40), which is a frequency band of the electromagnetic wave to be measured, 30 MHz. A constant intensity of electromagnetic waves can be obtained at ~ 1.5 GHz, resulting in excellent reliability of electromagnetic wave shielding performance.

Specifically, the electromagnetic wave shielding performance measurement system includes an electromagnetic wave shielding room 50, an electromagnetic wave transmitting unit, an electromagnetic wave receiving unit, and a sample fixation device.

The electromagnetic wave transmitting unit preferably includes a signal generator and a transmission antenna to generate and radiate electromagnetic waves at a desired frequency. Various types and types of transmission antennas may be used, but it is preferable to use a log periodic antenna (LP antenna).

The electromagnetic wave receiving unit may include a receiving antenna and a spectrum analyzer, and can measure electromagnetic waves radiated from the electromagnetic wave transmitting unit through the receiving antenna. Various types and types of receiving antennas may be used, but it is preferable to use the same type of antenna as the above-described transmitting antenna, for example, a log periodic antenna (LP antenna).

It is recommended that the signal generator, transmitting antenna, receiving antenna, and spectrum analyzer receive signals using a coaxial cable, and the control unit such as a computer or control PC to operate the electromagnetic wave shielding performance measurement system can be operated by the user, and the electromagnetic wave shielding performance measurement system can be operated by the user. There is no limitation as long as the location does not interfere with the measurement, and is preferably outside the electromagnetic wave shielding room 50.

The distance between the transmitting antenna and the receiving antenna is preferably 3m, 5m, or 10m, and is preferably 3m. Specifically, it is desirable that the distance between the measurement sample (1) and the transmitting antenna is about 2 m, and the distance between the measurement sample (1) and the receiving antenna is about 1 m.

If the distance between the transmitting antenna and the receiving antenna is too close, the influence of the near-field effect may increase, making it difficult to measure accurate electromagnetic wave shielding performance. If the distance is too far, it may be difficult to secure space for installing the antenna, and the size of the electromagnetic wave shielding room will increase, increasing costs. There is a growing problem.

The signal generator receives signals through a control PC, etc., and generates electromagnetic waves corresponding to them. The generated electromagnetic waves are radiated by a transmission antenna, and the transmission antenna is installed vertically or horizontally and radiates electromagnetic waves to the surroundings.

The radiated electromagnetic waves pass through the sample holding part 40 and are transmitted to the receiving antenna. The receiving antenna is installed in the same axial direction as the transmitting antenna, vertically or horizontally, and receives the signal and transmits it to the receiving unit connected to the receiving antenna.

The sample fixing device serves to fix the measurement sample (1) to the opening provided in the electromagnetic wave shielding room (50) while positioning it between the transmitting antenna and the receiving antenna, and the sample support part (30) of the above-mentioned electromagnetic wave shielding performance test device. and a sample fixing unit 40.

The electromagnetic wave shielding performance measurement system according to this aspect is a part where electromagnetic waves that are radiated and incident on the incident surface of the measurement sample (1) do not fully reach the receiving antenna due to factors other than reflection or absorption by the measurement sample (1). In order to minimize the sample support part 30 and the sample fixing part 40, it is in close contact with the gasket 33 of the sample support part 30 and the first and second frames 43 of the sample fixing part 40. The presence of the member 42 can prevent electromagnetic wave loss, and has the effect of significantly reducing electromagnetic wave loss in the 1 GHz region in particular and improving reliability.

Specifically, the gasket 33 prevents penetration or loss of electromagnetic waves in the small space between the sample and the sample support unit 30, and the first and second frames 43 are made of synthetic resin and the first and second frames are made of metal. Compared to the use of 2 frames (43), losses in the 1 GHz range have been eliminated, and the effects of other electromagnetic waves can be minimized by using foam gaskets provided around the outer edge of the incident surface of the measurement sample (1) and at the corners of the incident surface.

The features, structures, effects, etc. illustrated in each of the above-described embodiments can be combined or modified and implemented in other embodiments by a person with ordinary knowledge in the field to which the embodiments belong. Therefore, contents related to such combinations and modifications should be construed as being included in the scope of the present invention.

1: measurement sample
10: electromagnetic wave transmitter
20: electromagnetic wave receiver
30: sample support
31: plate
32: stand
33: gasket
34: panel
40: Sample fixing part
41: 1st frame
42: Adhesion member
43: 2nd frame
44: support
45: Distance adjustment screw
46: bearing
50: Electromagnetic wave shielding room
51: electromagnetic wave shielding wall

Claims (12)

An electromagnetic wave shielding performance measurement system that measures the electromagnetic wave shielding performance of the measurement sample by receiving electromagnetic waves radiated from the electromagnetic wave transmitter and passing through the measurement sample at the electromagnetic wave receiver,
An electromagnetic wave transmitting unit including a transmission antenna that radiates electromagnetic waves to the outside;
an electromagnetic wave receiving unit including a receiving antenna that receives the electromagnetic waves radiated from the electromagnetic wave transmitting unit;
a sample support unit that supports a measurement sample so that the measurement sample can be provided between the electromagnetic wave transmitting unit and the electromagnetic wave receiving unit, and includes a support stand; and
A first frame coupled to the support at a front side of the sample support, including an opening at the center, and made of a phenolic resin having a relative permittivity of 3.5 to 4.0, coupled to the support at the front of the first frame and an opening at the center. It includes a second frame and a sample fixing part that is coupled to the rear of the first frame and is in contact with the measurement sample and includes an adhesion member made of polyacetal with a relative dielectric constant of 3.5 to 4.0,
The electromagnetic wave transmitter radiates electromagnetic waves in the frequency range of 30 MHz to 1.5 GHz,
The support has a distance adjustment screw on the front side of the second frame that allows the first frame to move in the longitudinal direction of the support through manipulation,
The opening width (W2) of the second frame is 1.0 to 1.5 times the opening width (W1) of the first frame,
The measurement sample is an electromagnetic wave shielding performance measurement system with metal tape surrounding the sides. delete delete delete delete delete delete delete delete According to claim 1,
When the adhesion member is in close contact between the first frame and the measurement sample, the electromagnetic wave shielding performance measurement system extends from the opening of the first frame and includes a separation space surrounded by the adhesion member.
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