JP6217006B2 - Magnetic material loaded antenna - Google Patents

Description

  The present invention relates to a magnetic material loaded antenna and an antenna device, and more particularly to a small magnetic material loaded antenna and an antenna device.

  With the downsizing of communication terminals such as portable radio terminals, the need for downsizing transmission / reception antennas mounted on them has increased in recent years. Here, the “small antenna” refers to an antenna of λ (wavelength) /2π=0.154λ or less. For example, for a 310 MHz radio wave, λ is about 0.97 m. In other words, a small antenna refers to an antenna that is sufficiently smaller than the wavelength of the handled frequency. In general, a small antenna is said to be a good small antenna if it is sufficiently larger than an absolute gain of -20 dBi.

  A magnetic material loaded antenna as an example of a conventional antenna that can be reduced in size is disclosed in, for example, Japanese Patent Application Laid-Open No. 2006-222873 (Patent Document 1). According to the publication, a magnetic material loaded antenna is directed to a feeding element, a parasitic element made of a metal plate arranged at a predetermined interval with respect to the feeding element, and at least the feeding element side of the parasitic element. There is provided a magnetic material loaded antenna including a magnetic body laminated on a surface portion to be able to maintain good antenna performance while enhancing a wavelength shortening effect.

  Moreover, the example applied to the communication card is shown as another example. In this example, the communication card is formed by laminating a card magnetic body and a circuit board on a parasitic element for a card including a metal plate, and further disposing a card dielectric near the end of the card and incorporating it in the card dielectric. An antenna is provided. In use, the end of the card is inserted into a card slot such as a personal computer or PDA.

JP 2006-222873 A

  A conventional magnetically loaded antenna capable of being miniaturized has been configured as described above. Including a power feeding element, a parasitic element made of a metal plate arranged at a predetermined interval with respect to the feeding element, and a magnetic body stacked on a surface portion facing at least the feeding element side of the parasitic element, A pair of antenna coils is provided in part of the magnetic body.

  However, in Patent Document 1, there is no description about the absolute gain, the downsizing ratio is about 70%, and the metal conductor cannot be separated by a part of the antenna.

  Therefore, with such a configuration, the antenna is not necessarily a small antenna, and there is a possibility that the antenna may be increased in size and cost.

  In particular, for antennas with a wavelength of about 322 MHz or less in the vicinity of 1 m, the radio wave is very weak under Japanese law, and if it is a product that does not affect other frequencies, a weak radio that can be freely designed and its signal are allowed. Specific low power that allows signals with a certain strength of several thousand times is permitted under certain conditions.

  In particular, since weak wireless is not regulated by communication methods, a wide variety of devices are designed for short-range communication. Includes keyless entry of cars and TPMS (Tire Pressure Monitoring Systems).

  Against this background, there is also a need for design conditions for a small antenna that can efficiently transmit and receive radio waves having a wavelength in the vicinity of 1 m.

  The present invention has been made to solve the above-described problems, and can be surely reduced in size, and can be surely reduced in size and has a small change in gain with respect to a distance from a metal body, and an antenna device The purpose is to provide.

  A magnetic material loaded antenna according to the present invention includes a first ferrite layer, an insulator layer provided on the first ferrite layer, and an antenna coil provided on the insulator layer. The magnetic material loaded antenna is located a predetermined distance away from a metal body provided outside.

  Preferably, it further includes a second insulating layer provided on the antenna coil and a second ferrite layer provided on the second insulating layer.

  The antenna coil may be arranged in an adjacent quadrangular shape or may be arranged in an adjacent ∞ form.

  In another aspect of the present invention, the magnetic material loaded antenna is a magnetic material loaded antenna centered at 310 MHz. The magnetic material loaded antenna includes a ferrite layer and an antenna coil provided on the ferrite layer, and the winding form of the antenna coil is an adjacent quadrangular shape or an adjacent ∞ form, and the antenna coil is formed from a metal body provided outside. Located a predetermined distance apart.

  It is preferable that the distance between the metal body and the antenna coil is in close contact, or is separated by a predetermined distance.

  When the winding form of the antenna coil is an adjacent quadrangle, the predetermined distance is preferably 50 to 100 mm. Further, when the antenna coil is wound in the adjacent ∞ form, the predetermined distance is preferably 70 to 100 mm.

  In still another aspect of the present invention, an antenna device includes a first magnetic body having a coil wound around, a second magnetic body provided on the first magnetic body at an interval, and a second magnetic body. And an antenna coil provided on the magnetic body.

  According to the present invention, since the magnetic material loaded antenna is provided with the ferrite layer having a smaller area and the insulator layer on the metal body, and the antenna coil is provided thereon, the antenna coil and the ferrite layer are provided. Can be placed at regular intervals.

  As a result, the antenna can be miniaturized and can be integrated with a communication device that connects the antenna because it can be in close contact with metal, making it unnecessary to install the antenna, making the device compact, and transmission and reception capable of reducing costs. Equipment can be provided.

It is a figure which shows the magnetic body loading antenna which concerns on one embodiment of this invention. It is a perspective view which shows the whole structure of the magnetic material loading antenna shown in FIG. It is a figure which shows the magnetic body loading antenna which concerns on other embodiment. It is a figure which shows arrangement | positioning of the antenna coil in the magnetic material loading antenna of winding form B It is a figure which shows the frequency characteristic and antenna gain by the distance between the magnetic body of winding form A, and an antenna coil. It is a figure which shows the other example of the frequency characteristic by the distance between a magnetic body and an antenna coil, and an antenna gain. It is a figure which shows the further another example of the frequency characteristic by the distance of the antenna of winding form B, and an antenna gain by the distance. It is a figure which shows the further another example of the frequency characteristic and antenna gain by the distance of the antenna of winding form A, and a metal body. It is a figure which shows the relationship between the positional relationship of a metal body and a ferrite, and magnetic resistance. It is an image figure of a magnetic circuit in case a ferrite is a sandwich shape. It is a figure which shows the structure in the case of integrating and using a magnetic body loading antenna as a high frequency magnetic field communication antenna.

  Hereinafter, a magnetic material loaded antenna according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a magnetic material loaded antenna (hereinafter referred to as “antenna”) according to an embodiment of the present invention. FIG. 1A is a cross-sectional view showing the entire configuration of an antenna 10 that is located a predetermined distance away on a metal body provided outside, and FIG. 1B is shown in FIG. 1C is a cross-sectional view showing details of the antenna 10, and FIGS. 1C to 1E are arrow views (plan view) of portions indicated by arrows IC-IC, ID-ID, and IE-IE in FIG. Figure).

  Referring to FIGS. 1A to 1E, an antenna 10 is a rectangular parallelepiped as a whole, and has an upper plane having a predetermined area and is separated from a metal body 11 provided outside by a predetermined space d. To position. Here, the planar area of the antenna 10 is smaller than that of the metal body 11. The antenna 10 includes a first ferrite layer 12, a first insulating / dielectric layer 13 formed on the first ferrite layer 12, and an antenna coil 14 formed on the first insulating / dielectric layer 13. The second insulating / dielectric layer 15 formed on the antenna coil 14 and the second ferrite layer 16 formed on the second insulating / dielectric layer 15 are included. Here, the space d is shown as a space, but this may be another dielectric.

  Here, the dimensions of the three sides of the entire antenna 10 are λ / 2π × λ / 2π × λ / 10π or less, which satisfies the so-called small antenna. Here, for example, in this embodiment, when considering a frequency of 322 MHz or less that is intended for use, λ = 0.93 m, and the length × width × height is 150 mm × 150 mm × 30 mm, which is sufficient. It is low profile and compact.

  The antenna coil 14 includes a pair of connection terminals 21a and 21b and a pair of first antenna coil 21c and second antenna coil 21d connected to the respective terminals, and the first antenna coil 21c is connected to one of them. After extending from the terminal 21a and wound several times in the left direction, it is connected to the terminal 21b via a second antenna coil 21d wound adjacently in the right direction and wound several times in the right direction.

  FIG. 2 is a perspective view showing an overall configuration of the antenna device 20 in which the antenna 10 shown in FIG. 1 is optimized for a frequency of 310 MHz and is connected to the transceiver 23 via the connection unit 22.

  In this case, the characteristics of the ferrite are a relative magnetic permeability μ ′ = 16, a magnetic loss component μ ″ = 6, and a thickness of 1 mm (second ferrite layer 16) and 5 mm (first ferrite layer 12).

  The dielectric constant of the insulation / dielectric is about 1.5, the dimension of the second insulation / dielectric 13 is 0.3 to 1.8 mm, and the relative dielectric constant of the space d is 1.

  Here, the dimensions of a, b, and c of the antenna 10 shown in the figure are about a = 65 mm to 180 mm, b = 30 to 180 mm, and c = 5.6 to 10 mm, respectively.

  Referring to FIGS. 1 and 2, antenna 10 according to this embodiment is compact, can be reliably reduced in size, and has little change in gain with respect to the distance from the metal body. This is shown in Tables 1 to 3 described later.

  Next, another embodiment of the present invention will be described. FIG. 3 is a sectional view (A) showing a main part of an antenna 10a according to another embodiment of the present invention, and a diagram showing an antenna device 20a, corresponding to FIG. 1 (B) and FIG. 2, respectively. To do.

  In the embodiment shown in FIG. 3, the second insulating / dielectric layer 15 and the second ferrite layer 16 are not provided as compared with the previous embodiment.

  Here, the second insulating / dielectric layer 15 and the second ferrite layer 16 contribute only to shortening. When the second insulating / dielectric layer 15 is thinned, the ratio of the magnetic material surrounding the antenna is increased, the relative permeability is increased, the transmission speed of the electromagnetic wave is decreased, and as a result, the antenna may be shorter. For this reason, the effect of shortening the antenna is promoted.

  As a result, even the antenna according to this embodiment has the same effect as the previous embodiment. It should be noted that a magnetic field for canceling the second ferrite layer 16 shown in FIG. 10 later becomes stronger and the antenna gain is reduced.

  Next, a method for arranging the antenna coil will be described. FIG. 4 is a diagram showing the arrangement of antenna coils in the antenna 10. In FIG. 4A, an antenna coil is formed from a pair of adjacent coils, wound around a plurality of times from the outside to the inside from one terminal of the pair of adjacent terminals, and then on the right side from the inside. It is the structure which is connected to the other terminal through the second antenna coil wound a plurality of times in the left direction on the outside. Since this antenna coil is a form in which a pair of square coils are adjacent to each other, this winding form is referred to as a coil winding form A (or an adjacent square form).

  In FIG. 4B, the antenna coil is wound several times from the outside to the inside in the left direction from one terminal of a pair of adjacent terminals, and then wound multiple times in the right direction from the outside to the inside on the right side. The second antenna coil is connected to the other terminal. Since this antenna coil has a form in which a pair of coils are adjacent to each other in an infinite (∞) form, this winding form is referred to as a coil winding form B (or an adjacent ∞ form). This is the same arrangement as in FIG.

  FIG. 4C shows the arrangement of FIG. 4A in a rectangular shape that is long in the downward direction. FIG. 4D shows a case where the number of windings in the coil (winding form A) in FIG. FIG. 4E shows a case where the number of windings in the coil (winding form B) in FIG. 4B is two.

  Here, in the case of FIG. 4C, when the vertical and horizontal dimensions are, for example, 100 mm × 100 mm (the dimensions of the adjacent antenna coils are 100 mm × 50 mm), they are referred to as 100 mm square coils.

  Next, the antenna performance (design condition example) when applied to a specific frequency will be described using the antenna coil shown in FIG. Here, for example, a case where the frequency is 310 MHz will be described.

  First, as a reference antenna for comparing the performance of antennas, a simulation example (calculation example using simulation-free software MMANA) of a half-wave dipole antenna with a free-space matching dipole placed on a complete metal plane Table 1 shows. Here, the frequency is 310 MHz and 1 / 4λ is about 0.25 m. In this case, the VSWR (radio wave standing wave ratio) and the antenna gain, as well as the change in the bandwidth and circuit Q when the gain is recovered by tuning (when in close contact with the metal plate) from the metal wall surface. Indicates the value according to the distance. Here, a gain of 9 dBi is all obtained when recovered in synchronization. Also shown here are values for matching in free space away from the metal surface.

  Here, the free space matching dipole refers to the following. The antenna is strongly influenced by objects in the surrounding space. In the simulation, it is calculated that there is only air up to infinity around the antenna. That is, it is an image that there is a metal wall that extends infinitely under the antenna on a completely metal plane.

  As shown in Table 1, at a distance of 1 cm from the metal surface, even a half-wave dipole has an attenuation of about 40 dB. If matching is possible, 9 dBi can be obtained in a specific direction, but the 3 dB bandwidth is as narrow as 270 kHz. It is attenuated by about 40dB with an offset of ± 2.5MHz, and is very steep. When the band is narrow and dynamics exist in the surrounding space, it is susceptible to fluctuations and cannot be used for a plurality of channels, which is not practical. Dipole has VSWR 1.5 and antenna gain 2.13dBi in free space.

  Usually, a monopole antenna is wound in a coil shape or wrapped with ferrite, or wound around ferrite to shorten the antenna. On the other hand, an antenna such as a dipole sandwiches a dielectric having a high dielectric constant between a metal and equivalently shortens the antenna length. When mounting such a stable broadband and low-loss antenna on a metal body, it is important to move the entire antenna away from the metal surface or protrude from the metal surface. Has been taken.

  Next, a design example of the antenna in this embodiment will be described. Here, two types of antenna coils of length × width = 100 × 50 mm are simulated. One is a coil-shaped antenna of length × width = 100 × 50 mm, 7 turns, 0.2 mmφ electric wire by a coil of winding form B. The simulation results in this case are shown in Table 2.

  The other is a coil-shaped antenna of length × width = 100 × 50 mm, 7 turns, 0.2 mmφ electric wire by a coil of winding form A. The simulation results in this case are shown in Table 3.

  In each case, the value when the distance from the metal surface of the present invention is 2 mm is also shown in the rightmost column.

  Here, the simple tuning means the case where the antenna coil is arranged (joined) with the distance from the ferrite narrowed. In this case, the antenna characteristics are improved by the mutual positional relationship between the antenna coil and the ferrite.

  As shown in Tables 2 and 3, with this size antenna, even if the distance from the metal surface is 10 mm, the bandwidth is extremely narrow and it cannot be put into practical use. On the other hand, in this embodiment, even if the distance from the metal surface is about 2 mm, a gain of about -20 dBi is obtained with a bandwidth of 30 to 40 MHz and an effective antenna is obtained.

  The inventor confirmed that if the frequency is in the vicinity of 310 MHz, it can be effectively used as a magnetic material loaded antenna if this configuration having a winding type antenna coil of winding form A or B is used. did. Therefore, the antenna gain for each frequency due to the change in the distance between the magnetic material such as the first ferrite 12 shown in FIG. 1 and the antenna coil 14 (the thickness of the insulating / dielectric layer 13) was measured. The results will be described below.

  FIG. 5A is a graph showing the antenna gain for each frequency according to the change in the distance between the first ferrite 12 that is a magnetic material and the antenna coil 14 shown in FIG. 5 (B) is a graph showing the relationship between the distance between the magnetic body and the antenna coil 14 and the antenna gain for a specific frequency in the winding form B. FIG. The difference in distance between the magnetic body and the antenna coil 14 is as shown in FIG. The peak of the mountain shown in the graph moves from a low frequency to a high frequency due to a difference in distance between the magnetic body and the antenna coil 14. It can be seen that when the distance is 80 mm, it does not work as an antenna in this frequency band.

  Referring to FIG. 5A, when a space is formed between the two by a dielectric, the circuit Q becomes high and the communication band becomes narrow, and a peak starts to appear at a high frequency that the antenna coil waits. When the space is further expanded, the characteristics of the antenna coil start to appear strongly. Although the antenna is tuned to a high frequency, it alone attenuates greatly due to mismatch.

  Table 4 shows the relationship between the tuning frequency (dBi peak frequency) and the insulation / dielectric thickness from FIG. 5A. From Table 4, it can be seen that the tuning frequency and the dielectric / dielectric thickness are in a proportional relationship.

  Further, from FIG. 5B, in order to obtain an antenna gain in which the center frequency is 310 MHz and the range of 10 MHz before and after that, that is, the band of 300 to 320 MHz can be received at -20 dBi or more, the magnetic body and the antenna coil It can be seen that the interval of is preferably 0.3 to 1.8 mm.

  FIG. 6A is a graph showing the antenna gain for each frequency according to a change in the distance between the first ferrite 12 that is a magnetic body and the antenna coil 14 when the antenna coil is in the winding form A, and FIG. B) is a graph showing the relationship between the distance between the magnetic body and the antenna coil 14 and the antenna gain for a specific frequency when the antenna coil is in the winding form A. Table 4 shows the relationship between the frequency to be tuned (peak frequency of dBi) and the thickness of the insulating / dielectric material from FIG. 6 (A). Also in this example, the peak of the mountain moves from a low frequency to a high frequency due to a difference in space.

  FIG. 6B shows that the optimum value is between 0.5 mm and 1 mm. Both are good because the reception gain is about -15 dBi.

  Next, the relationship between the metal body 11 and the space d of the antenna (the sum of the ferrite 12, the insulating / dielectric body 13, and the antenna coil 14) indicated by d in FIG.

  FIG. 7A is a graph showing the relationship between the metal body 11 and the antenna space d in the case of the antenna coil winding configuration B, and FIG. 7B shows the metal body and the antenna coil 14 for a specific frequency. It is a graph which shows the relationship between the distance between and antenna gain.

  Table 6 shows the extracted relationship between the frequency to be tuned (the peak frequency of dBi) and the space d from FIG.

  In this embodiment, the gap can be set so that when the antenna is in contact with the metal body 11 and when it is in free space, the antenna gain becomes a center frequency of 310 MHz. In addition, there is no fluctuation in the large gain as shown by other antennas. An example of the result is shown.

  Referring to FIGS. 7A and 7B, when the distance between the metal body and the antenna (wrapping form B) is 310 MHz, it is effective as a small antenna even when the space d is between 7 mm and 52 mm. A gain of -20 dBi is obtained, but it can be seen that if it is placed in close contact with a metal body or placed in free space, it operates as an effective antenna.

  Further, although not explicitly shown in FIGS. 7A and 7B, a gain of about −12 dBi was obtained at a space d of about 1500 mm and frequencies of 300 MHz, 310 MHz, and 320 MHz.

  FIG. 8A is a graph showing the relationship between the metal body and the antenna space d when the winding form of the antenna coil is A, and FIG. 8B shows the metal body and the antenna coil 14 for a specific frequency. It is a graph which shows the relationship between the distance between and antenna gain.

  Table 8 shows the relationship between the frequency to be tuned (peak frequency of dBi) and the space d from FIG.

  Referring to FIG. 8A, when the center frequency is 310 MHz, if the space C is about 2 mm to 100 mm (free space), a gain of −20 dBi effective as an antenna can be obtained.

  Here, when the distance between the metal body and the antenna (wrapping form A) is in close contact or 70 to 100 mm apart, a gain of −20 dBi can be obtained, that is, the antenna can operate as an effective antenna. I understand.

  Table 9 shows specific data in FIG.

  Although not explicitly shown in FIGS. 8A and 8B, a gain of about -10 dBi was obtained at a frequency of 300 MHz, 310 MHz, and 320 MHz with a space d of about 1500 mm.

  From FIG. 7B and FIG. 8B, it can be read that the gain is restored when the two types of antennas are in close contact with the metal. It decreases once in several tens of millimeters, and the antenna gain is improved as a shortened antenna.

  This point will be described below. FIG. 9 is a diagram showing the relationship between the positional relationship between the metal body and ferrite and the magnetic resistance. FIG. 9A shows a case where the metal body 11 and the ferrite are in close contact. In this case, it is considered that the current for canceling the electric field inside the metal body creates a magnetic field, the antenna magnetic circuit flows efficiently, induction to the antenna coil in contact with the magnetic circuit occurs, and an antenna reception signal is generated. That is, magnetic resistance B> magnetic resistance A.

  On the other hand, when the antenna moves away from the metal body, the resistance of the magnetic circuit rapidly increases and the magnetic flux decreases. When the antenna further moves away, the magnetic material reduces the phase velocity of the radio wave, functions as a shortened antenna, and begins to recover the gain. The magnitude of the magnetic resistance in this case is shown in FIG. As shown here, the magnetic resistance B <the magnetic resistance A.

  Next, the case where the metal body 11 has a single magnetic body 12 shown in FIG. 3A, and the case where the metal body 11 has two layers of ferrite magnetic body 12 shown in FIG. 1A. Will be described with reference to FIGS. 10A and 10B.

  Referring to FIG. 10, the current generated in coil 14 is caused by the difference between the magnetic flux density around the coil of ferrite 12 and the magnetic flux density on the opposite side. In the case of a single layer of magnetic material 12 as shown in FIG. 10A, no magnetic flux is generated on the opposite side, so that an appropriate magnetic flux density can be obtained.

  On the other hand, when the magnetic body 12 as shown in FIG. 10B has a two-layer structure, since the difference in magnetic flux density is small, the current generated by the coil is small, so that it is difficult to obtain a large signal. However, since the magnetic permeability surrounding the coil as a whole increases and the shortening rate due to the magnetic permeability increases, the antenna gain in free space can be improved.

  Next, another embodiment of the present invention will be described. In this embodiment, a magnetic material loaded antenna is combined with a low frequency magnetic field generating ferrite antenna.

  In triggering devices used for tag activation and communication in keyless entry fixed-station magnetic field transmission / reception antennas and semi-active tags in front doors of automobiles and houses, frequencies near 100 kHz are used as transmission media for RFID tags. In many cases, the transmission antenna having this mechanism is a large-diameter coil or a coil wound around ferrite. In particular, ferrite coils are often used because they can create a strong magnetic field in the space.

  Similarly, the ferrite portion used in the above-described embodiment can be made of the same material. Accordingly, a copper wire having an appropriate wire diameter is wound around a plate-like ferrite to constitute a high-frequency communication magnetic field antenna, a ferrite layer is formed on one surface thereof, and an insulating layer and an antenna coil layer are overlaid. Thereby, the high frequency communication magnetic field antenna and the magnetic material loaded antenna can be integrated. This antenna device is excited by a high-frequency magnetic field, and a tag (RFID) receives and processes high-frequency magnetic field data. For example, it is optimal for a mechanism that receives an area ID, connects it with its own ID, and returns it as a 310 MHz band radio signal. .

  FIG. 11 is a diagram illustrating a configuration of an antenna device 30 in which a magnetic material loaded antenna and a high frequency magnetic field communication antenna are combined. 11A is an exploded perspective view of the antenna device 30, and FIG. 11B is a diagram showing the relationship between the magnetic material loaded antenna 10 shown in FIG. 1A and the antenna device 30, and FIG. FIG. 2C is a schematic cross-sectional view of the antenna device 10.

  An antenna device 30 according to this embodiment will be described with reference to FIG. The antenna device 30 includes an upper layer 31 and a lower layer 41 provided below the upper layer 31. The upper layer 31 includes a ferrite 32, an insulating layer 33 provided on the ferrite 32, and an antenna coil 34 provided on the insulating layer 33.

  The lower layer 41 is a rectangular parallelepiped ferrite 42, a high frequency communication coil 44 wound around the center of the ferrite 42 a plurality of times, and a ferrite provided on the upper surface of the ferrite 42 so as to sandwich the high frequency communication coil 44. Spacers 43a and 43b formed, and spacers 45a and 45b formed of ferrite provided on the lower surface of the ferrite 42 and sandwiching the high frequency communication coil 44 are included. The high frequency communication coil 44 is connected to a pair of terminals 46a and 46b.

  11A and 11B, the ferrite 32, the insulating layer 33, and the antenna coil 34 constituting the upper layer 31 are the ferrite 12 and the insulating layer shown in FIG. 13 and the antenna coil 14. Further, the ferrite 42 provided at a distance d by the spacers 43 a and 43 b corresponds to the metal body 11. Accordingly, the upper layer 31 and the ferrite 42 of the lower layer 41 operate as the receiving antenna described in FIG.

  On the other hand, the ferrite 42 around which the high frequency communication coil 44 constituting the lower layer 41 is wound operates as a high frequency magnetic field communication antenna.

  A schematic cross-sectional view of these specific structures is shown in FIG.

  By configuring the antenna device 30 in this way, a transmission / reception device having a compact configuration can be provided.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  According to the present invention, the antenna can be miniaturized and can be integrated with a communication device for connecting the antenna because it can be in close contact with metal, so that the antenna installation work is not required, the device is compact, and the cost is reduced. Since it can be used as a possible transmitting / receiving device, it is advantageously used as a magnetic material loaded antenna or transmitting / receiving device.

  DESCRIPTION OF SYMBOLS 10 Antenna, 11 Metal body, 12 1st ferrite layer, 13 1st insulation and dielectric material layer, 14 Antenna coil, 15 2nd insulation and dielectric material layer, 16 2nd ferrite layer, 20 Antenna apparatus, 21a, 21b Connection terminal 21c First antenna coil, 21d Second antenna coil, 23 Transmitter / receiver, 30 Antenna device, 31 Upper layer, 32 Ferrite, 33 Insulating layer, 34 Antenna coil, 41 Lower layer, 42 Ferrite, 43a, 43b, 45a, 45b Spacer, 44 High-frequency communication coil, 46a, 46b terminal

Claims (7)

A first ferrite layer;
An insulator layer provided on the first ferrite layer;
A magnetic material loaded antenna including an antenna coil provided on the insulator layer ,
Located a predetermined distance away from the metal body provided outside ,
A second insulating layer provided on the antenna coil;
A magnetic material loaded antenna further including a second ferrite layer provided on the second insulating layer and capable of emitting electromagnetic waves . The magnetic material loaded antenna according to claim 1, wherein the antenna is centered at 310 MHz. The magnetic material-loaded antenna according to claim 1, wherein the antenna coil is disposed in an adjacent quadrangular state. The magnetic material-loaded antenna according to claim 1, wherein the antenna coil is arranged in an adjacent ∞ form. The magnetic material loaded antenna according to claim 2 ,
A magnetic material-loaded antenna in which a distance between the metal body and the antenna coil is in close contact or is separated by a predetermined distance. The magnetic material-loaded antenna according to claim 5 , wherein when the antenna coil is wound in an adjacent quadrilateral state, the predetermined distance is 50 to 100 mm. The magnetic material-loaded antenna according to claim 5 , wherein when the antenna coil is wound in an adjacent ∞ form, the predetermined distance is 70 to 100 mm.

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