JP2021136389A - Magnetic shield sheet - Google Patents

Abstract

To provide a magnetic shield sheet that exerts an electromagnetic wave suppression effect even at high frequencies from MHz to GHz in order to prevent leakage electromagnetic fields from a component that generates electromagnetic waves such as a coil in an electronic circuit, wiring, or the like.SOLUTION: A magnetic shield sheet according to an embodiment of the present invention for reducing the electromagnetic field leaking from a solenoid coil in a wireless power transmission circuit has a flat plate shape having a surface that is close to at least one of two end faces that are substantially perpendicular to the length direction of the solenoid coil, or close to a side surface that is substantially parallel to the length direction of the solenoid coil, and faces the end face or side surface, and includes a magnetic material in which a real component μ' of the relative permeability (complex relative permeability μr=μ'-jμ") in a high frequency band over a range of one digit or more from 1 MHz to 30 GHz is 1 or more, and the imaginary component μ" is 0.2 or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a magnetic shield sheet, and more specifically, to a magnetic shield sheet for reducing a magnetic field radiated from an element by installing it in the vicinity of an element that generates a magnetic field in an electric / electronic circuit.

Recently, as mobile information and communication devices such as personal computers (PCs), mobile phones, and digital cameras have become smaller and more multifunctional, and the calculation processing speed has increased, the drive frequency has become more and more high-frequency. The spread of high-frequency equipment is steadily expanding. Demand for devices such as satellite communications, mobile communications, and car navigation systems that use electromagnetic waves in the microwave band has increased significantly in recent years, such as automobile toll collection systems (ETC), short-range wireless communications such as wireless LAN, and collision prevention radar. In-vehicle millimeter-wave radar and the like have also begun to spread. With the progress of the use of high frequencies as described above, there is a strong demand for magnetic materials that can follow changes in electromagnetic fields at high frequencies without loss.

On the other hand, the deterioration of the electromagnetic environment due to the electromagnetic waves emitted by these high-frequency devices to the outside world has been regarded as a problem, and the movement of legal regulations and self-regulation by public institutions and international organizations is currently becoming active. However, it is a very difficult problem to deal with because there is a contradictory causal relationship that even a signal that is useful in each device becomes an obstacle for other devices and living organisms. Especially in recent years, since the use of wireless power transmission technology has begun, devices that generate electromagnetic waves with higher frequencies and higher output than before have appeared, and these electromagnetic waves have become a problem of adverse effects on other control devices. living.

In addition, due to the extremely high integration density of each electronic element installed in the electronic circuit, the electromagnetic field generated in small-scale ICs and small-scale circuits such as on-board power supplies has an effect as noise on adjacent circuits and wiring. It is becoming a problem. In order to solve this problem, as a characteristic of the equipment, it does not emit unnecessary electromagnetic waves and has strong resistance to external noise, that is, both generation of electromagnetic waves (EMI) and damage (EMS) are taken into consideration. It is important to establish electromagnetic compatibility (EMC).

As an example of the above EMC countermeasures, an electromagnetic noise absorbing material that has been often used in electronic devices has a function of suppressing the emission of electromagnetic waves to the outside world in the vicinity of an electromagnetic noise generation source. In the high frequency region of several MHz or higher, sheet-like electromagnetic waves that absorb high-frequency electromagnetic noise such as harmonics transmitted through the line using natural resonance such as Ni-Zn ferrite and convert it into thermal energy to suppress the noise. Noise absorbing materials (magnetic shield sheets) are often used. The required magnetic properties are two points: a high relative permeability of the magnetic material and a high natural resonance frequency. Since ferrite has a high electrical resistivity, performance deterioration due to eddy current loss is small, and it has been regarded as a preferable material in the high frequency region.

By the way, the relative magnetic permeability of a material in an AC magnetic field, such as when an electromagnetic wave is acting, is _{expressed as μ r} = μ'−jμ ”in complex number representation. The complex relative magnetic permeability μ _r is a real part and an imaginary number. It is divided into parts, which are μ'and μ', respectively. Here, j is an imaginary unit. Generally, the larger the real part of the relative permeability, the stronger the amplification effect of the magnetic flux density, and the larger the imaginary part, the stronger the loss effect of converting the magnetic field into heat or the like. Since the real part and the imaginary part of this complex relative magnetic permeability have frequency dependence, the relative magnetic permeability has different values depending on the frequency of the magnetic field.

For example, most of the other magnetic materials such as ferrite mentioned above are excellent as high-frequency magnetic materials because the relative magnetic permeability decreases at frequencies above MHz, while the high relative magnetic permeability can be maintained up to around GHz. It can be said that there is.

Conventional magnetic shield sheets utilize the fact that magnetic materials with excellent high-frequency characteristics have a large imaginary component of relative permeability in the high-frequency region, and mainly organic materials are powdered with magnetic materials with excellent high-frequency characteristics. By mixing it in the body etc., it converts electromagnetic waves into heat and lowers the electromagnetic wave intensity to suppress mutual interference and malfunction between each electronic component and electronic devices, and also to suppress the influence on the human body etc. (For example, Patent Document 1). This magnetic shield sheet technology is smaller and lighter than the magnetic shield shield having a structure surrounded by a conductor plate, and has high insulation properties, so that it has an advantage especially when used in a high-density integrated circuit among electronic circuits.

Many passive components such as capacitors, coils, and transformers are included in electronic circuit components. Among them, electromagnetic fields are locally concentrated in coils and transformers that act on magnetic fields to control the voltage and current characteristics of electronic circuits. In addition, the electromagnetic field leaks from it, which may cause interference with peripheral parts and circuit malfunction. Recently, while the density of electronic circuits has been increasing, the operating frequency of circuits has been improved, so that the conventional magnetic shield sheet has insufficient function to prevent electromagnetic waves. Therefore, there are cases where the arrangement layout such as the distance and direction between the parts is restricted and the circuit cannot be sufficiently integrated.

Conventionally, as a magnetic shield sheet for parts that leak and radiate electromagnetic waves such as coils and transformers of electronic circuits, materials such as ferrite with a natural resonance frequency of GHz or less are mainly made into powder of mm size or less and mixed with organic substances. Has been used in. Utilizing the characteristic that the complex relative magnetic permeability μ "has a peak value in a specific frequency region, the intensity of the electromagnetic wave transmitted through the sheet is suppressed by converting the electromagnetic wave into heat in a desired frequency region.

Recently, in addition to ferrite, new magnetic materials having relative permeability in the high frequency range have been developed. These new magnetic materials are used as magnetic powders having a size of μm or nm, and typical materials include rare earth-iron-nitride magnetic materials (for example, Nd-Fe-N). (For example, Patent Document 2). The magnetic permeability of these magnetic powders can be adjusted in the frequency band of the magnetic permeability according to the size of the powder. As a result, it has become possible to manufacture a magnetic shield sheet in which the relative magnetic permeability is adjusted in a desired frequency range in the range of several MHz to several GHz to change the absorption characteristics.

However, the frequency band in which the imaginary part μ "of the relative permeability can take a large value is very narrow compared to the frequency range in which the real part μ'can take a large value. Furthermore, magnetic materials at high frequencies exceeding MHz In both cases, the original μ _r was much smaller than that of the material at frequencies below kHz, so μ “could not be sufficiently large. Therefore, it has been difficult to expand the frequency range in the conventional magnetic shield sheet used at a frequency of MHz or higher.

Japanese Patent Application Laid-Open No. 2008-210861 Patent No. 5669389

An object of the present invention is to provide a magnetic shield sheet that exhibits an electromagnetic wave suppression effect even at high frequencies from MHz to GHz in order to prevent leakage electromagnetic fields from parts that generate electromagnetic waves such as coils in electronic circuits and wiring. be.

The magnetic shield sheet for reducing the electromagnetic field leaking from the solenoid coil in the wireless power transmission circuit of one aspect of the present invention is close to at least one of two end faces substantially perpendicular to the length direction of the solenoid coil, or the solenoid coil. It has a flat plate shape that is close to a side surface that is substantially parallel to the length direction of the solenoid and has a surface that faces the end surface or the side surface, and has a relative permeability in a high frequency band over a range of one digit or more from 1 MHz to 30 GHz. Includes a magnetic material in which the real component μ'of (complex relative magnetic permeability μ _r = μ'-jμ ") is 1 or more and the imaginary component μ" is 0.2 or less.

The magnetic shield sheet for reducing the electromagnetic field leaking from the transformer in the electronic circuit of one aspect of the present invention has a flat plate shape having a surface close to the end face of the transformer and facing the end face, and has a flat plate shape of 1 MHz to 30 GHz. _{The real component μ'of the relative permeability (complex relative permeability μ r} = μ'−jμ ”) in the high frequency band over a range of one digit or more is 1 or more and the imaginary component μ ”is 0.2 or less. Includes magnetic materials that are.

The magnetic shield sheet for reducing the electromagnetic field leaking from the electronic components, wirings, or between the electronic components in the electronic circuit of one aspect of the present invention is close to the surface between the electronic components, the wiring, or the electronic components, and is on the surface. _{It has a flat plate shape with facing surfaces, and is a real component μ of the relative permeability (complex relative permeability μ r} = μ'−jμ ”) in the high frequency band over a range of one digit or more from 1 MHz to 30 GHz. Includes magnetic materials in which'is 1 or more and the imaginary component μ'is 0.2 or less.

The magnetic shield sheet for reducing the electromagnetic field leaking from the antenna of one aspect of the present invention has a surface that is close to the end portion on the side opposite to the side that emits the electromagnetic field for transmission of the antenna and faces the end portion. _{It has a flat plate shape, and the real component μ'of the relative permeability (complex relative permeability μ r} = μ'-jμ ") in the high frequency band over a range of one digit or more from 1 MHz to 30 GHz is 1 or more. It contains a magnetic material having an imaginary component μ "of 0.2 or less.

According to the present invention, the following effects can be obtained.
(1) It is possible to suppress an electromagnetic field leaking between solenoid coils, transformers, electronic components in electronic circuits, wiring, between electronic components, or from an antenna, and reduce adverse effects on other peripheral devices.
(2) The suppression (reduction) of the leaked electromagnetic field is particularly effective in the high frequency band from MHz to GHz.
(3) Electromagnetic interference and noise of parts and wiring on electronic circuits are suppressed, and restrictions on layout layout such as distance and direction between parts are relaxed, so it is possible to further increase the integration density of electronic circuits. It becomes.

It is a figure which shows the magnetic shield sheet of one Embodiment (coil) of this invention. It is a figure which shows the magnetic field suppression effect of the magnetic field shielding sheet of one Embodiment (coil) of this invention. It is a figure which shows the magnetic field suppression effect of the magnetic field shielding sheet of one Embodiment (coil) of this invention. It is a figure which shows the magnetic shield sheet of another embodiment (wireless power supply) of this invention. It is a figure which shows the magnetic shield sheet of another embodiment (transformer) of this invention. It is a figure which shows the magnetic shield sheet of another embodiment (electronic component) of this invention. It is a figure which shows the magnetic shield sheet of another embodiment (electronic circuit) of this invention. It is a figure which shows the magnetic shield sheet of another embodiment (antenna) of this invention. It is a figure which shows the magnetic shield sheet of another embodiment (wiring) of this invention. It is a figure which shows the magnetic shield sheet of another embodiment (between electronic parts) of this invention.

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a magnetic shield sheet according to an embodiment (coil) of the present invention. In the example of FIG. 1, magnetic shield sheets 2 and 3 are arranged on both sides of the solenoid coil (air core coil) 1. The magnetic shield sheets 2 and 3 may be arranged close to at least one of two end faces (cross sections) substantially perpendicular to the length direction of the solenoid coil 1. Further, the magnetic shield sheet can be arranged along the side surface substantially parallel to the length direction of the solenoid coil 1 of FIG. 1 in place of or in addition to the magnetic shield sheets 2 and 3 on the end faces. The magnetic shield sheets 2 and 3 are joined to, for example, their end face or side surface (hereinafter, simply referred to as an end face) or arranged at a position of about several mm to 1 cm from the end face. The magnetic shield sheets 2 and 3 have a flat plate shape having a surface facing the end face of the solenoid coil 1.

Although FIG. 1 shows a magnetic shield sheet having a disk shape, it is not limited to the disk shape and may be a square (square or rectangle). When arranged along the side surface of the solenoid coil 1, a rectangular shape is preferable. The size (size) may be such that there is a surface having a size that covers at least a part or all of the end face of the solenoid coil 1. The thickness may be in the range of, for example, several tens of μm to 1 cm, which can be processed. The magnetic shield sheet may be adhered to the end face of the solenoid coil 1 with double-sided tape or the like.

The magnetic shield sheets 2 and 3 are made of a magnetic material for high frequency, specifically, for example, the relative magnetic permeability in a high frequency band over a range of one digit or more from 1 MHz to 30 GHz (complex relative magnetic permeability μr = μ'−jμ). Includes a magnetic material in which the real component μ'of ") is 1 or more and the imaginary component μ" is 0.2 or less. Here, "over a range of one digit or more out of 1 MHz to 30 GHz" means a frequency range in which the frequency changes by one digit or more, for example, 10 MHz to 100 MHz and 300 MHz to 3 GHz (the same applies hereinafter). ). This is due to the fact that the frequency range changes by one digit or more depending on the particle size of the high-frequency magnetic material.

Magnetic materials include and for example _{Nd x Fe 100-x-y} N less nitride retentive typified _y magnetic material. In one form of the magnetic shield sheet, one in which _{fine particles of a magnetic material such as Nd 2} Fe ₁₇ N ₃ are mixed in a thermosetting resin (for example, an epoxy resin) can be used. The size (particle size) of the fine particles of the magnetic material is, for example, in the range of about several μm to several tens of μm.

Real _{Nd x Fe 100-x-y} N in addition to the relative magnetic permeability in a high frequency band over a range of more than an order of magnitude of 1MHz~30GHz also of _y (complex relative permeability μr = μ'-jμ ") As a magnetic material having a component μ'of 1 or more and an imaginary component μ of 0.2 or less, it _{has a composition of R x} Fe _100-xy N _y , and R is Y, Ce, Pr, Nd, Gd. , Tb, Dy, Ho, Er, Tm, Lu, Sm, at least one compound material, or amorphous magnetic particles containing a magnetic metal mainly composed of Fe, and the surface of the magnetic particles is Examples thereof include materials characterized by being covered with an oxide film composed of a glass phase.

FIG. 2 shows an experimental example in which a magnetic sheet is actually arranged on the end face of the solenoid coil 1 to reduce the electromagnetic field strength of harmonic components up to 13.56 MHz and 300 MHz or higher. FIG. 2A shows the experimental result with the air-core solenoid coil, and FIG. 2B shows the experimental result when the magnetic shield sheet is attached to one end surface of the solenoid coil 1. In the case of FIG. 2B, magnetic sheets having the same diameter with respect to the cross-sectional shape of the coil were arranged. The measurement area is an area of 18 mm × 20 mm above the end face of the solenoid coil 1. When the electromagnetic field distribution was evaluated by a two-dimensional scan of the electromagnetic field probe, the electromagnetic field strength in the region far from the coil end face on the upper left side of the figure was significantly reduced when the magnetic shield sheet of (b) was attached. The result was obtained (the dark color area where the electromagnetic field strength is weak is wide).

FIG. 3 is an example verified by electromagnetic field simulation. The horizontal axis in the figure is the distance (mm) from the end face of the solenoid coil 1, and the vertical axis is the electromagnetic field strength (dBμV). Graph A is an air-core coil, B is a case where a circular magnetic shield sheet is attached to one end surface of the coil, and C is a case where a vertically stretched magnetic shield sheet is attached along the side surface of the coil. In terms of the positive magnetic permeability μ'value of the magnetic material, it corresponds to A: about 1, B: about 2, and C: about 4 to 5, respectively. From FIG. 3, it can be seen that the effect of suppressing the electromagnetic field strength in the presence of the magnetic shield sheets B and C increases as the distance from the end face of the solenoid coil 1 increases.

Although this embodiment has been described air-core coils, if the coil and the magnetic core using a magnetic core 'is _core mu of a magnetic-shield sheets' permeability mu is used smaller than (mu' _core <_μ'sheet ) is also included in the scope of the present invention.

FIG. 4 is a diagram showing a magnetic shield sheet of another embodiment (wireless power supply) of the present invention. This embodiment assumes a transformer of a power converter or a coupler of wireless power supply. The magnetic shield sheets 6 and 7 similar to the magnetic shield sheets 2 and 3 of the first embodiment of FIG. 1 are arranged on both sides of the coil 4 on the power transmission side and the coil 5 on the power reception side. The shapes and sizes of the magnetic shield sheets 6 and 7, the characteristics of the magnetic material used, material examples, etc. are basically the same as those of the magnetic shield sheets 2 and 3 of FIG. 1 described above, so the description thereof is omitted here. do. With this structure, it is possible to suppress the electromagnetic field strength in the space ahead (outside) where the magnetic shield sheets 6 and 7 are arranged.

FIG. 5 is a diagram showing a magnetic shield sheet of another embodiment (transformer) of the present invention. This embodiment is an example in which a magnetic shield sheet is used when the core shape is not a simple rod shape because it is a transformer of an electronic circuit. A magnetic shield sheet 9 similar to the magnetic shield sheets 2 and 3 of the first embodiment of FIG. 1 is arranged on the front surface of the transformer 8. The shape and size of the magnetic shield sheet 9, the characteristics of the magnetic material used, material examples, and the like are basically the same as those of the magnetic shield sheets 2 and 3 of FIG. 1 described above, and thus the description thereof will be omitted here. With this structure, it is possible to suppress the electromagnetic field strength in the space ahead (outside) where the magnetic shield sheet 9 is arranged.

FIG. 6 is a diagram showing a magnetic shield sheet of another embodiment (electronic component) of the present invention. This embodiment is an example in which a magnetic shield sheet is applied to an electronic component such as a power transistor or a diode in an electric circuit. A magnetic shield sheet 11 similar to the magnetic shield sheets 2 and 3 of the first embodiment of FIG. 1 is arranged on the surface of the electronic component 10. The shape and size of the magnetic shield sheet 11, the characteristics of the magnetic material used, material examples, and the like are basically the same as those of the magnetic shield sheets 2 and 3 of FIG. 1 described above, and thus the description thereof will be omitted here. With this structure, it is possible to suppress the electromagnetic field strength in the space ahead (outside) where the magnetic shield sheet 11 is arranged.

FIG. 7 is a diagram showing a magnetic shield sheet of another embodiment (electronic circuit) of the present invention. This embodiment is an example in which a magnetic shield sheet is applied to an electronic circuit (electric circuit) including a plurality of electronic components. A magnetic shield sheet 13 similar to the magnetic shield sheets 2 and 3 of the first embodiment of FIG. 1 is arranged on the surface of the electronic circuit 12. The shape and size of the magnetic shield sheet 13, the characteristics of the magnetic material used, material examples, and the like are basically the same as those of the magnetic shield sheets 2 and 3 of FIG. 1 described above, and thus the description thereof will be omitted here. With this structure, it is possible to suppress the electromagnetic field strength in the space ahead (outside) where the magnetic shield sheet 13 is arranged.

FIG. 8 is a diagram showing a magnetic shield sheet of another embodiment (antenna) of the present invention. In this embodiment, the electromagnetic field in the vicinity is suppressed by arranging the magnetic shield sheet with respect to the antenna. A magnetic shield sheet 15 similar to the magnetic shield sheets 2 and 3 of the first embodiment of FIG. 1 is arranged close to one end surface of the antenna 14. The antenna 14 can include not only generally famous Yagi-Uda antennas and bar antennas, but also various antennas such as patch antennas and ring-shaped antennas, regardless of size.

The shape and size of the magnetic shield sheet 15, the characteristics of the magnetic material used, material examples, and the like are basically the same as those of the magnetic shield sheets 2 and 3 of FIG. 1 described above, and thus the description thereof will be omitted here. The main use of this structure is to install the magnetic shield sheet 15 on the side opposite to the side that radiates the electromagnetic field from the antenna 14 to suppress the radiation of unnecessary electromagnetic fields to the periphery. Further, it is also possible to apply the magnetic shield sheet not only on the side opposite to the radial surface but also in various directions including the lateral direction.

FIG. 9 is a diagram showing a magnetic shield sheet according to another embodiment (wiring) of the present invention. This embodiment is an example used for suppressing an electromagnetic field emitted from an electronic circuit and wiring of an electric circuit. A magnetic shield sheet 18 similar to the magnetic shield sheets 2 and 3 of the first embodiment of FIG. 1 is arranged on the surface of the wiring 17 on the electronic circuit board. The shape and size of the magnetic shield sheet 18, the characteristics of the magnetic material used, material examples, and the like are basically the same as those of the magnetic shield sheets 2 and 3 of FIG. 1 described above, and thus the description thereof will be omitted here. The influence of inductance of the wiring 17 included in the electronic circuit 16 cannot be ignored, especially when the wiring length exceeds 1 mm. By installing the magnetic shield sheet 18 at that time, it is possible to suppress the electromagnetic field strength in the space ahead (outside) where the magnetic shield sheet 18 is installed.

FIG. 10 is a diagram showing a magnetic shield sheet of another embodiment (between electronic components) of the present invention. This embodiment is an application for suppressing noise and malfunction due to an electromagnetic field generated between electronic components by installing a magnetic shield sheet between electronic components included in an electronic circuit or an electric circuit. A magnetic shield sheet 20 similar to the magnetic shield sheets 2 and 3 of the first embodiment of FIG. 1 is arranged on the surface between the two electronic components 19 and 20 on the electronic circuit board 16. The shape and size of the magnetic shield sheet 20, the characteristics of the magnetic material used, material examples, and the like are basically the same as those of the magnetic shield sheets 2 and 3 of FIG. 1 described above, and thus the description thereof will be omitted here. For example, a small switching power supply on an electronic circuit board 16 and passive components of its peripheral circuits may generate a relatively strong electromagnetic field. At that time, by installing the magnetic shield sheet 21, the electromagnetic field strength can be reduced and mutual interference and noise between electronic components can be reduced.

An embodiment of the present invention has been described with reference to the drawings. However, the present invention is not limited to these embodiments. Further, the present invention can be carried out in a mode in which various improvements, modifications and modifications are added based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

The magnetic shield sheet of the present invention transmits power by electromagnetic wave propagation in space, especially in a power transmission circuit in a high frequency or ultrahigh frequency region, which is mainly used for power equipment and information communication related equipment, even when metal conductors are not in contact with each other. It is used to reduce the electromagnetic field that leaks in transformers, inductors, reactors, cores, antennas, and microwave elements used in circuits.

1: Solenoid coil,
2, 3, 6, 7, 9, 11, 13, 15, 18, 21: Magnetic shield sheet,
4, 5: Coil,
8: Transformers 10, 19, 20: Electronic components 12, 16: Electronic circuits (electric circuits)
14: Antenna 17: Wiring

Claims (6)

A magnetic shield sheet for reducing the electromagnetic field leaking from the solenoid coil in the wireless power transmission circuit.
It has a flat plate shape that is close to at least one of two end faces that are substantially perpendicular to the length direction of the solenoid coil, or close to a side surface that is substantially parallel to the length direction of the solenoid coil, and has a surface that faces the end face or the side surface. death,
_{The real component μ'of the relative magnetic permeability (complex relative magnetic permeability μ r} = μ'-jμ ") in the high frequency band over a range of one digit or more from 1 MHz to 30 GHz is 1 or more and the imaginary component μ" A magnetic shield sheet containing a magnetic material having a value of 0.2 or less. It is a magnetic shield sheet for reducing the electromagnetic field leaking from the transformer in the electronic circuit.
It has a flat plate shape with a surface that is close to the end face of the transformer and faces the end face.
_{The real component μ'of the relative magnetic permeability (complex relative magnetic permeability μ r} = μ'-jμ ") in the high frequency band over a range of one digit or more from 1 MHz to 30 GHz is 1 or more and the imaginary component μ" A magnetic shield sheet containing a magnetic material having a value of 0.2 or less. A magnetic shield sheet for reducing electromagnetic fields leaking from electronic components, wiring, or between electronic components in an electronic circuit.
It has a flat plate shape that is close to the surface between electronic components, wiring, or electronic components and has a surface facing the surface.
_{The real component μ'of the relative magnetic permeability (complex relative magnetic permeability μ r} = μ'-jμ ") in the high frequency band over a range of one digit or more from 1 MHz to 30 GHz is 1 or more and the imaginary component μ" A magnetic shield sheet containing a magnetic material having a value of 0.2 or less. A magnetic shield sheet to reduce the electromagnetic field leaking from the antenna.
It has a flat plate shape that is close to the end on the side opposite to the side that radiates the electromagnetic field for transmission of the antenna and has a surface facing the end.
_{The real component μ'of the relative magnetic permeability (complex relative magnetic permeability μ r} = μ'-jμ ") in the high frequency band over a range of one digit or more from 1 MHz to 30 GHz is 1 or more and the imaginary component μ" A magnetic shield sheet containing a magnetic material having a value of 0.2 or less. The magnetic material has a composition of R _x Fe _100-xy N _y , and R is selected from Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm. Either a compound material which is at least one kind, or an amorphous magnetic particle containing a magnetic metal mainly composed of Fe, and the surface of the magnetic particle is coated with an oxide film made of a glass phase. The magnetic shield sheet according to any one of claims 1 to 4, which comprises both. The magnetic shield sheet according to claim 5, wherein particles containing either or both of the R _x Fe _100-xy N _{y and amorphous magnetic particles are mixed in the thermosetting resin.}

Images