JP6782340B1 - Electromagnetic wave absorption unit and electronic circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic wave absorption unit and an electronic circuit capable of preventing electromagnetic wave noise from leaking to the outside and suppressing interference of electromagnetic wave noise from an electromagnetic wave noise generation source on the same substrate with other circuits on the substrate. SOLUTION: An electromagnetic wave absorbing unit is placed on a box-shaped shield member having an opening, a dielectric member provided on an inner surface of the shield member, and a dielectric member sandwiched between the dielectric members so as to face the shield member. It is provided with a plurality of metal plates having a long portion, which are separately arranged in a. [Selection diagram] Fig. 1

Description

The present invention relates to an electromagnetic wave absorbing unit and an electronic circuit.

In recent years, a wide variety of electronic devices have been used, but these electronic devices are easily affected by electromagnetic wave noise, and it is required to shield unnecessary electromagnetic waves (noise) in order to operate normally. In Patent Document 1, a wireless circuit board is arranged on a shield case main body, a shield case lid is arranged corresponding to the position of the wireless circuit board, and the wireless circuit board is sandwiched between the shield case lid and the shield case main body. A shield device capable of preventing leakage of electromagnetic waves (noise) from a substrate is disclosed.

Japanese Unexamined Patent Publication No. 2000-151174

The shield device of Patent Document 1 can prevent electromagnetic waves from the wireless circuit board from leaking to the outside of the shield device. However, if a noise source such as an oscillator and other electronic components are mounted on the same board, the electronic components may be interfered with by electromagnetic waves from the noise source even if there is such a shield device. There is.

The present invention has been made in view of such circumstances, and prevents electromagnetic wave noise from leaking to the outside, and electromagnetic wave noise from an electromagnetic wave noise source on the same substrate interferes with other circuits on the substrate. It is an object of the present invention to provide an electromagnetic wave absorption unit and an electronic circuit that can be suppressed.

The electromagnetic wave absorbing unit according to the embodiment of the present invention includes a box-shaped shield member having an opening, a dielectric member provided on the inner surface of the shield member, and the shield member with the dielectric member in between. It includes a plurality of metal plates having a long portion, which are arranged so as to face each other and separately on the dielectric member.

In the above configuration, the plurality of metal plates may be arranged along the longitudinal direction and / or the direction intersecting the longitudinal direction of the elongated portion. By arranging in this way, the effect of suppressing electromagnetic noise can be enhanced.
Further, the lengths of the elongated portions of the plurality of metal plates may be different. With such a configuration, the frequency band of electromagnetic noise to be suppressed can be expanded.
Further, the shield member includes a top plate facing the opening and a side plate erected from the peripheral edge of the top plate, a dielectric member is provided on the inner surface of the top plate, and a plurality of metal plates are provided with the dielectric member. It may be configured so as to face the top plate in between and separately arranged on the dielectric member. With such a configuration, since the metal plate can be arranged on the top plate having a large area, the number of metal plates that can be arranged can be increased, and the frequency band of the electromagnetic wave noise to be suppressed can be further expanded.
Further, in the above configuration, the dielectric member may be provided on the inner surface of the side plate, and a plurality of metal plates may be arranged separately on the dielectric member so as to face the side plate with the dielectric member in between. With such a configuration, electromagnetic wave noise can be absorbed even in the region of the side plate, so that the electromagnetic wave noise absorption effect can be further enhanced.
Further, the electronic circuit according to the embodiment of the present invention includes any of the above-described electromagnetic wave absorbing units, a first circuit having an electronic component and / or a semiconductor element that generates electromagnetic wave noise, and an electromagnetic wave from the first circuit. A second circuit having electronic components and / or semiconductor elements that interfere and are affected by electromagnetic noise is provided with a circuit unit provided on the substrate, and the edge of the opening of the electromagnetic wave absorbing unit so as to cover the circuit unit of the substrate. It has a structure in which a portion is brought into contact with a substrate.

According to the present invention, not only can it be suppressed that electromagnetic wave noise from a circuit that generates electromagnetic wave noise provided on a substrate leaks to the outside and affects other circuits, but also other circuits provided on the same substrate. It is also possible to suppress interference due to electromagnetic noise.

It is an external perspective view which shows an example of the structure of the electromagnetic wave absorption unit of this embodiment. It is sectional drawing of the main part which shows the 1st example of the structure of the electronic circuit of this embodiment. It is explanatory drawing which shows the 1st example of the arrangement of a plurality of metal plates. It is explanatory drawing which shows the typical structure of the electromagnetic wave absorption unit and an example of an equivalent circuit. It is explanatory drawing which shows the 1st example of the absorption performance of the electromagnetic wave by the electromagnetic wave absorption unit. It is explanatory drawing which shows the 2nd example of the arrangement of a plurality of metal plates. It is explanatory drawing which compares and shows the absorption performance of the electromagnetic wave about the structure of the 2nd example of the electromagnetic wave absorption unit shown in FIG. It is explanatory drawing which shows the 3rd example of the arrangement of a plurality of metal plates. It is sectional drawing of the main part which shows the 2nd example of the structure of the electronic circuit of this embodiment.

Hereinafter, the present invention will be described with reference to the drawings showing the embodiments. FIG. 1 is an external perspective view showing an example of the configuration of the electromagnetic wave absorbing unit of the present embodiment. The electromagnetic wave absorbing unit faces the shield member 10 with a box-shaped shield member 10 having a rectangular opening 17, a dielectric member 20 provided on the inner surface of the shield member 10, and the dielectric member 20 in between. A plurality of metal plates 30 having a long portion, which are separately arranged on the dielectric member 20, are provided. That is, the shield member 10 and the plurality of metal plates 30 are arranged to face each other with the dielectric member 20 interposed therebetween.

The shield member 10 is made of metal, and includes a rectangular top plate 16 facing the opening 17, and side plates 11, 12, 13, and 14 erected from the peripheral edge of the top plate 16. The dielectric member 20 is provided on the inner surface of the top plate 16, and a plurality of metal plates 30 are separately arranged on the dielectric member 20 so as to face the top plate 16 with the dielectric member 20 in between. That is, the top plate 16 and the plurality of metal plates 30 are arranged to face each other with the dielectric member 20 interposed therebetween. The ends of each of the side plates 11, 12, 13, and 14 are extended in parallel with the top plate 16 to form a contact portion 15 that abuts on the substrate described later.

In the present embodiment, a thin metal plate may be used as the shield member 10, and a dielectric layer made of, for example, polyimide may be provided on the surface of the top plate 16 of the shield member 10 to form the dielectric member 20. Then, after forming a metal layer on the surface of the dielectric member 20 by plating or the like, a plurality of long metal plates 30 can be formed by removing by etching leaving a predetermined region portion. However, the present invention is not limited to this configuration. For example, copper foils are attached to both sides of an insulating sheet, the copper foil on one side is used as a shield member 10, and a predetermined region portion of the other copper foil. The metal plate 30 may be formed by etching and removing the others while leaving the above. In this case, the insulating sheet becomes the dielectric member 20.

FIG. 2 is a cross-sectional view of a main part showing a first example of the configuration of the electronic circuit of the present embodiment. The electronic circuit includes an electromagnetic wave absorbing unit and a circuit unit. The circuit unit includes a substrate 40, a first circuit (oscillator 41, transmission module 42) mounted on the substrate 40, a second circuit (reception module 43), and the like. The oscillator 41 is, for example, a voltage-controlled oscillator (VCO), and when a triangular wave-shaped modulated signal is input, it outputs a modulated signal in a required frequency band. The transmission module 42 performs processing such as multiplication and amplification on the signal input from the oscillator 41, and outputs the processed signal from the transmission antenna. The receiving module 43 acquires the signal received by the receiving antenna and outputs it to a signal processing module (not shown) mounted on the substrate 40.

For example, a rectangular shield pattern is formed on the substrate 40 so as to surround the oscillator 41, the transmission module 42, the reception module 43, and the like, and the contact portion 15 of the shield member 10 is brought into contact with the shield pattern. , The shield member 10 can be fixed to the substrate 40. The method of fixing the shield member 10 to the substrate 40 may be screwing or fitting. Further, the contact portion 15 can be soldered to the shield pattern.

The edge of the opening 17 of the electromagnetic wave absorbing unit is brought into contact with the substrate 40 so as to cover the circuit unit of the substrate 40. That is, the contact portion 15 (edge portion) of the opening 17 of the electromagnetic wave absorption unit is brought into contact with the substrate 40, and the oscillator 41, the receiving module 43, and the like are covered with the shield member 10. The oscillator 41, the transmission module 42, and the reception module 43 on the substrate 40 are examples, and are not limited to these. Electronic components and elements that are so-called noise sources and noise sources that leak electromagnetic waves. Any electronic component or element that interferes with the electromagnetic waves from the source and is affected by noise may be used.

FIG. 3 is an explanatory view showing a first example of arrangement of a plurality of metal plates 30. FIG. 3 is a view of the top plate 16 viewed from the opening 17 of the shield member 10, for example. Each of the plurality of metal plates 30 has a long portion, and the length of the long portion is shown by L. The plurality of metal plates 30 are arranged at intervals d2 along the longitudinal direction of the long portion. Further, the plurality of metal plates 30 are arranged at intervals d1 along the direction intersecting the longitudinal direction of the long portion. Further, for the metal plate arranged in the nearest vicinity of the side plate of the shield member 10, the distance between the short side of the long portion and the shield member 10 (side plate) is d3, and the longitudinal side of the long portion and the shield. The distance from the member 10 (side plate) is d4. The intervals d1 to d4 can be appropriately determined based on the frequency to be suppressed by impedance matching as described later. For example, d1 can be 5 mm, d2 can be 2 mm, d3 can be 1 mm, and d4 can be 2 mm. .. Further, the material, thickness, dielectric constant, etc. of the dielectric member 20 can also be appropriately determined based on the frequency at which electromagnetic waves are desired to be suppressed. In the example of FIG. 3, six metal plates 30 are arranged, but the number of metal plates 30 is not limited to six.

In the example of FIG. 3, a rectangle is shown as the long portion of the metal plate 30, but the shape of the metal plate 30 is not limited to the example of FIG. 3, as long as the shape includes the long portion. Good. For example, as the shape of the metal plate 30, at least one end of the long portion on the short side may be bent in an L shape. That is, the planar shape of the metal plate 30 may be L-shaped, substantially S-shaped, or U-shaped.

FIG. 4 is an explanatory diagram showing an example of a schematic structure and an equivalent circuit of the electromagnetic wave absorption unit. As shown in FIG. 4A, in the electromagnetic wave absorbing unit, the shield member 10 and the plurality of metal plates 30 are arranged to face each other with the dielectric member 20 in between, and the plurality of metal plates 30 are spaced on the dielectric member 20. It is separated and arranged. Each of the plurality of metal plates 30 constitutes an inductance component according to the wavelength (frequency) of the electromagnetic wave according to the length of the long portion, and is between the metal plate 30 and between the metal plate 30 and the shield member 10. Consists of the capacitance component.

As shown in FIG. 4B, the equivalent circuit of the electromagnetic wave absorption unit can be approximately represented by the inductance component and the capacitance component as an example, and the resonance phenomenon between the inductance component and the capacitance component causes a free space in a certain band. Inductance matching can be achieved, and electromagnetic waves can be taken into the electromagnetic wave absorption unit (the shield member 10, the dielectric member 20, and the entire plurality of metal plates 30). That is, the reflection of electromagnetic waves in a certain band inside the shield member 10 is suppressed.

FIG. 5 is an explanatory diagram showing a first example of the electromagnetic wave absorption performance by the electromagnetic wave absorption unit. In the figure, the horizontal axis represents the frequency and the vertical axis represents the amount of electromagnetic wave absorbed. In FIG. 5, graphs A1, A2, and A3 show simulation results of absorption performance when the length L of the metal plate 30 is 5.0 mm, 5.5 mm, and 6.0 mm. The width of the long portion of the metal plate 30 was set to 1 mm, and the intervals d1 and d2 shown in FIG. 3 were set to 10 mm.

As shown in FIG. 5, the length L of the long portion is related to the frequency at which the electromagnetic wave absorption unit absorbs the electromagnetic wave greatly. In other words, by changing the length L of the long portion, the frequency at which the amount of electromagnetic wave absorption peaks can be adjusted. As a result, for example, by adjusting the length of the metal plate 30 according to the frequency of the signal generated by the oscillator 41 or the like that can be a noise source, electromagnetic waves from noise sources in different frequency bands can be absorbed. Can be done.

By changing the arrangement of the plurality of metal plates 30, the capacitance component between the metal plates 30 and the capacitance component between the metal plate 30 and the shield member 10 can be changed, and as a result, the amount of electromagnetic wave absorption is adjusted. be able to. Further, the amount of electromagnetic wave absorption can be adjusted by changing the material, thickness, dielectric constant, etc. of the dielectric member 20. As a result, for example, by changing the arrangement of the plurality of metal plates 30 according to the arrangement of the oscillator or the electronic component on the substrate or the oscillation frequency of the oscillator, the electromagnetic wave leaking from the oscillator interferes with the electronic component or the like. Can be suppressed.

FIG. 6 is an explanatory view showing a second example of the arrangement of the plurality of metal plates 30. In FIG. 6, the three upper metal plates 30 are arranged at intervals (for example, d1) along the direction intersecting the longitudinal direction of the long portion, and the length of the metal plates 30 is L1. , L2 (> L1), L3 (> L2), and so on, from left to right in the figure. Further, the lower three metal plates 30 are arranged at intervals (for example, d1) along the direction intersecting the longitudinal direction of the long portion, and the lengths of the metal plates 30 are L3. Like L2 (<L3) and L1 (<L2), they become shorter from left to right in the figure.

In the present embodiment, as shown in FIG. 6, the lengths of the long portions of the plurality of metal plates 30 are not limited to be different, and for example, a plurality of metal plates 30 having different lengths. The metal plate may be arranged along the longitudinal direction of the elongated portion, or may be arranged along the direction intersecting the longitudinal direction of the elongated portion. Further, the difference in the length of the long portion does not mean that the lengths of all the metal plates are different, and includes the case where two of the six metal plates are the same as shown in FIG. This means that at least some of the plurality of metal plates need to have different lengths.

FIG. 7 is an explanatory diagram showing a comparison of electromagnetic wave absorption performance for the configuration of the second example of the electromagnetic wave absorption unit shown in FIG. In the figure, the horizontal axis represents the frequency and the vertical axis represents the amount of electromagnetic wave absorbed. The graph indicated by reference numeral A shows the case where the lengths of the plurality of metal plates 30 are the same, and the graph indicated by reference numeral B shows the case of the second example in which the lengths of the plurality of metal plates 30 are different. As can be seen from FIG. 7, by arranging a plurality of metal plates 30 having different lengths of the long portions, it is possible to make a plurality of frequencies at which the absorption amount of the electromagnetic wave peaks, and as a result, the electromagnetic wave can be absorbed. The frequency bandwidth can be widened.

As described above, the contact portion 15 of the opening 17 of the electromagnetic wave absorbing unit is brought into contact with the substrate 40, and the oscillator 41 and the receiving module 43 are covered with the shield member 10. As a result, the electromagnetic wave leaking from the oscillator 41 can be absorbed by the electromagnetic wave absorbing unit, and the electromagnetic wave leaking from the oscillator 41 can be suppressed from interfering with the receiving module 43.

FIG. 8 is an explanatory view showing a third example of the arrangement of the plurality of metal plates 30. In FIG. 8A, the four upper metal plates 30 are arranged at intervals along the direction intersecting the longitudinal direction of the long portion. The longitudinal direction of the long portion of the lower three metal plates 30 is such that the longitudinal direction of the elongated portion intersects the longitudinal direction of the upper four metal plates 30. The lower three metal plates 30 are also arranged at intervals along the direction intersecting the longitudinal direction of the long portion.

In FIG. 8B, the five metal plates 30 are arranged along a direction parallel to the longitudinal direction of the elongated portion while being spaced along a direction intersecting the longitudinal direction of the elongated portion. In the case of FIG. 8B, it can be said that the plurality of metal plates 30 are arranged at intervals along the longitudinal direction of the long portion, or the plurality of metal plates 30 are arranged on the long portion. It can also be said that they are arranged at intervals along the direction intersecting the longitudinal direction.

In FIG. 8C, a plurality of metal plates 30 are arranged at intervals along the longitudinal direction of the long portion. In FIG. 8D, a plurality of metal plates 30 are arranged at intervals along a direction intersecting the longitudinal direction of the long portion. In addition, in FIG. 8C or FIG. 8D, only one metal plate 30 may be provided. By devising the arrangement (arrangement) of the metal plates 30 as shown in FIGS. 8A to 8D, it is possible to reduce noise at specific polarizations and locations of electromagnetic waves. Further, although not shown, an array of a plurality of metal plates 30 may be arranged in an L shape. In this case, the arrangement direction (direction in which the metal plates 30 are arranged) may intersect with the longitudinal direction of the metal plates 30, or may intersect with the direction intersecting the longitudinal direction (short direction).

As described above, by changing the arrangement of the plurality of metal plates 30, the capacitance component between the metal plates 30 and the capacitance component between the metal plate 30 and the shield member 10 can be changed, and as a result, the electromagnetic wave The amount of absorption can be adjusted. Further, by changing the arrangement of the plurality of metal plates 30 according to the arrangement of the oscillator and the electronic component on the substrate or the oscillation frequency of the oscillator, the electromagnetic wave leaking from the oscillator interferes with the electronic component and the like. Can be suppressed.

FIG. 9 is a cross-sectional view of a main part showing a second example of the configuration of the electronic circuit of the present embodiment. As shown in FIG. 9, in the electromagnetic wave absorbing unit, the dielectric member 20 is provided on the inner surface of the side plates 11 to 14 (side plates 11 and 13 are shown in FIG. 9), and a plurality of metal plates 30 are provided on the inner surface of the side plates 11 to 14 (the side plates 11 and 13 are shown in FIG. In between, they are separated and arranged on the dielectric member 20 so as to face each of the side plates 11 to 14.

That is, the side plates 11 to 14 and the plurality of metal plates 30 are arranged to face each other with the dielectric member 20 interposed therebetween. Thereby, for example, it is possible to further suppress that the electromagnetic wave leaking from the oscillator 41 is reflected by the side plates 11 to 14 and interferes with the electronic components and the like. Depending on the arrangement of the parts on the substrate 40, the dielectric member 20 is provided only on a part of the side plates 11 to 14, and the dielectric member 20 is sandwiched between the side plates and a plurality of metals. The plate 30 may be arranged so as to face each other.

According to the electromagnetic wave absorption unit of the present embodiment, it is possible to obtain a high electromagnetic wave shielding effect targeting only a wide frequency band or a part of a specific frequency band. Further, by changing the lengths of the plurality of metal plates, the frequency band in which the electromagnetic shielding effect is required can be easily adjusted. Further, by making the plurality of metal plates different in length, it is possible to widen the frequency band in which the electromagnetic shielding effect is required.

In the above-described embodiment, the top plate 16 has a rectangular shape, and the shield member 10 has a rectangular parallelepiped box shape having an opening 17, but the structure of the shield member 10 is not limited to this. For example, the shape of the top plate 16 may be a polygon such as a circle, an ellipse, a triangle, a trapezoid, or a pentagon, depending on the shape of the substrate 40, the arrangement of parts on the substrate 40, and the like. In the shape of the top plate 16, the shape of the shield member 10 can be changed as appropriate.

The electromagnetic wave absorbing unit of the present embodiment has a box-shaped shield member having an opening, a dielectric member provided on the inner surface of the shield member, and the dielectric member in between, and faces the shield member. It includes a plurality of metal plates having a long portion, which are separately arranged on the dielectric member.

The electromagnetic wave absorbing unit is arranged separately on the dielectric member so as to face the shield member with the box-shaped shield member having an opening, the dielectric member provided on the inner surface of the shield member, and the dielectric member in between. It is provided with a plurality of metal plates having a long portion. That is, the shield member and the plurality of metal plates are arranged to face each other with the dielectric member sandwiched between them.

The plurality of metal plates form an inductance component according to the wavelength (frequency) of the electromagnetic wave, and form a capacitance component between the metal plates and between the metal plate and the shield member. Impedance matching with free space can be achieved in a certain band by the resonance phenomenon of the inductance component and the capacitance component, and electromagnetic waves are taken into the electromagnetic wave absorption unit (shield member, dielectric member, and the entire plurality of metal plates). Can be done.

The edge of the opening of the shield member can be brought into contact with the required portion of the object. The required location can be, for example, a location that surrounds the oscillator, the electronic component, or the like when an element that can be a noise source such as an oscillator and an electronic component or the like are mounted on the substrate. As a result, the electromagnetic wave leaking from the oscillator can be absorbed by the electromagnetic wave absorbing unit, and the electromagnetic wave leaking from the oscillator can be suppressed from interfering with the electronic component or the like. That is, not only can it be suppressed that electromagnetic wave noise from a circuit that generates electromagnetic wave noise provided on the board leaks to the outside and affects other circuits, but also for other circuits provided on the same board. Interference due to electromagnetic noise can be suppressed.

In the electromagnetic wave absorbing unit of the present embodiment, the plurality of metal plates are arranged along the longitudinal direction of the elongated portion and / or the direction intersecting the longitudinal direction.

The plurality of metal plates are arranged along the longitudinal direction of the long portion. The length of the long portion is related to the frequency at which the electromagnetic wave absorption unit absorbs electromagnetic waves more. In other words, by changing the length of the long portion, the frequency at which the amount of electromagnetic wave absorption peaks can be adjusted. Further, by changing the arrangement of the plurality of metal plates, the capacitance component between the metal plates and between the metal plate and the shield member can be changed, and as a result, the amount of electromagnetic wave absorption can be adjusted. As a result, for example, by changing the arrangement of a plurality of metal plates according to the arrangement of the oscillator or the electronic component on the substrate or the oscillation frequency of the oscillator, the electromagnetic wave leaking from the oscillator is suppressed from interfering with the electronic component or the like. it can.

Further, the plurality of metal plates are arranged along the direction intersecting the longitudinal direction of the long portion. By changing the arrangement of the plurality of metal plates, the capacitance component between the metal plates and between the metal plates and the shield member can be changed, and as a result, the amount of electromagnetic wave absorption can be adjusted. As a result, for example, by changing the arrangement of a plurality of metal plates according to the arrangement of the oscillator or the electronic component on the substrate or the oscillation frequency of the oscillator, the electromagnetic wave leaking from the oscillator is suppressed from interfering with the electronic component or the like. it can.

In the electromagnetic wave absorbing unit of the present embodiment, the lengths of the long portions of the plurality of metal plates are different.

The lengths of the long parts of multiple metal plates are different. For example, a plurality of metal plates having different lengths of the long portion may be arranged along the longitudinal direction of the long portion, or may be arranged along the direction intersecting the longitudinal direction of the long portion. By arranging a plurality of metal plates having different lengths of long portions, it is possible to have a plurality of frequencies at which the amount of electromagnetic wave absorption peaks, and as a result, the frequency bandwidth capable of absorbing electromagnetic waves can be widened. it can.

In the electromagnetic wave absorbing unit of the present embodiment, the shield member includes a top plate facing the opening and a side plate erected from the peripheral edge of the top plate, and the dielectric member is placed on the inner surface of the top plate. The plurality of metal plates are provided and arranged separately on the dielectric member so as to face the top plate with the dielectric member in between.

The shield member includes a top plate facing the opening and a side plate erected from the peripheral edge of the top plate. A dielectric member is provided on the inner surface of the top plate, and a plurality of metal plates are separately arranged on the dielectric member so as to face the top plate with the dielectric member in between. That is, the top plate and the plurality of metal plates are arranged to face each other with the dielectric member sandwiched between them.

As a result, for example, it is possible to prevent electromagnetic waves leaking from the oscillator from being reflected by the top plate and interfering with electronic components and the like.

In the electromagnetic wave absorbing unit of the present embodiment, the dielectric member is also provided on the inner surface of the side plate, and the plurality of metal plates are placed on the dielectric member with the dielectric member in between and facing the side plate. They are placed separately.

A dielectric member is also provided on the inner surface of the side plate, and a plurality of metal plates are separately arranged on the dielectric member with the dielectric member in between and facing the side plate. That is, the side plates and the plurality of metal plates are arranged to face each other with the dielectric member sandwiched between them. Thereby, for example, it is possible to further suppress that the electromagnetic wave leaking from the oscillator is reflected by the side plate and interferes with the electronic component or the like.

The electronic circuit of the present embodiment interferes with the above-mentioned electromagnetic wave absorbing unit, a first circuit having an electronic component and / or a semiconductor element that generates electromagnetic wave noise, and electromagnetic waves from the first circuit, and causes electromagnetic wave noise. A second circuit having electronic components and / or semiconductor elements affected by the above is provided with a circuit unit provided on the substrate, and an edge of an opening of the electromagnetic wave absorbing unit is provided so as to cover the circuit unit of the substrate. It has a configuration in which it is in contact with the substrate.

The electronic circuit interferes with the electromagnetic wave absorption unit, the first circuit that generates electromagnetic wave noise (for example, a circuit having an electronic component and / or a semiconductor element), and the electromagnetic wave from the first circuit, and is affected by the electromagnetic wave noise. A second circuit (for example, a circuit having an electronic component and / or a semiconductor element) to be received includes a circuit unit provided on a substrate. The first circuit has, for example, an oscillator. Further, the second circuit has, for example, a receiving unit that receives a signal via a receiving antenna. Then, the edge of the opening of the electromagnetic wave absorbing unit is brought into contact with the substrate so as to cover the circuit unit of the substrate.

As a result, the electromagnetic wave leaking from the first circuit can be absorbed by the electromagnetic wave absorbing unit, and the electromagnetic wave leaking from the first circuit can be suppressed from interfering with the second circuit.

The embodiments and examples disclosed above are exemplary in all respects and are not restrictive.

10 Shield member 11, 12, 13, 14 Side plate 15 Contact part 16 Top plate 17 Aperture 20 Dielectric member 30 Metal plate 40 Board 41 Oscillator 42 Transmit module 43 Receive module

Claims (6)

A box-shaped shield member with an opening,
A dielectric member provided on the inner surface of the shield member and
An electromagnetic wave absorbing unit including a plurality of metal plates having a long portion, which are separately arranged on the dielectric member with the dielectric member in between and facing the shield member. The plurality of metal plates are
The electromagnetic wave absorbing unit according to claim 1, which is arranged along the longitudinal direction of the elongated portion and / or the direction intersecting the longitudinal direction. The electromagnetic wave absorbing unit according to claim 1 or 2, wherein the lengths of the elongated portions of the plurality of metal plates are different. The shield member is
The top plate facing the opening and
A side plate erected from the peripheral edge of the top plate is provided.
The dielectric member is provided on the inner surface of the top plate.
The invention according to any one of claims 1 to 3, wherein the plurality of metal plates are separated and arranged on the dielectric member so as to face the top plate with the dielectric member in between. Electromagnetic wave absorption unit. The dielectric member is also provided on the inner surface of the side plate.
The electromagnetic wave absorption unit according to claim 4, wherein the plurality of metal plates are separated and arranged on the dielectric member so as to face the side plate with the dielectric member in between. The electromagnetic wave absorption unit according to any one of claims 1 to 5.
A first circuit having an electronic component and / or a semiconductor element that generates electromagnetic noise, and a second circuit having an electronic component and / or a semiconductor element that interferes with the electromagnetic waves from the first circuit and is affected by the electromagnetic noise. The circuit is equipped with a circuit unit provided on the board.
An electronic circuit having a configuration in which an edge portion of an opening of the electromagnetic wave absorbing unit is brought into contact with the substrate so as to cover the circuit unit of the substrate.

Images