JP5564953B2 - ANTENNA DEVICE AND ELECTRONIC DEVICE - Google Patents

Description

  The present invention relates to an antenna device and an electronic apparatus including the antenna device.

In recent years, in-vehicle GPS (Global Positioning System) receiving car navigation devices or portable handheld GPS receivers have been put into practical use at low cost and are widely used. In recent years, GPS receivers and receiver modules have been downsized due to advances in technologies such as digital communication and mobile communication, and miniaturization of parts such as shortening and miniaturization with dielectric ceramics or ferroelectric materials. Yes. Furthermore, various types of ultra-compact portable GPS receivers or position detection systems such as wristwatches have been proposed.
In this type of consumer GPS receiver, as a receiving antenna, a patch-type planar antenna or a cylindrical helical housed in a separate housing from the receiver, or a patch-type antenna built in the receiver housing, etc. It is used.
Among them, in a watch case, a dielectric, a plate-like radiation conductor provided on the front side of the dielectric, a plate-like ground conductor provided on the back side of the dielectric, and a radiation conductor There is known a patch type antenna device provided with a power feeding member electrically connected to the antenna (for example, Patent Document 1).

JP 2009-17308 A

  By the way, ceramic has a high dielectric constant and good loss characteristics (that is, a low dielectric loss tangent, which is a degree of electric energy loss), and therefore is suitable as a dielectric in a patch type antenna device. On the other hand, since it is vulnerable to impact, when the electronic device incorporating the antenna device is dropped or shaken strongly, the dielectric may break against a nearby component. Further, there is a possibility that the tool touches the dielectric when the electronic device is repaired, and the dielectric is broken.

  The present invention has been made in view of such problems, and an object thereof is to provide an antenna device excellent in impact resistance and an electronic device including the antenna device.

First aspect of the present invention, comprises the front side to the radiation conductor across the dielectric, an antenna structure ground conductor on the back side is provided, in close contact with the dielectric, a dielectric rubber a resilient surround The dielectric rubber is an antenna device characterized by having a relative dielectric constant of 1 or more and smaller than a relative dielectric constant of the dielectric .

According to the antenna device and the radio wave receiving device configured as described above, the following effects can be obtained.
According to the present invention, since the elastic dielectric rubber surrounds at least the periphery of the dielectric in the antenna structure, the impact is absorbed or buffered by the dielectric rubber when dropped, etc. In addition to preventing damage to the dielectric in the structure, it employs a configuration in which the dielectric is surrounded by a dielectric rubber around the side surface of the dielectric. As a result, the shape of the antenna structure is substantially increased, and the reception sensitivity can be significantly improved.
Further, when the dielectric rubber is provided in close contact with the dielectric, the shape of the antenna structure is substantially increased, so that the antenna gain is improved and the frequency band is increased.
In addition, in the case where the dielectric constant of the dielectric rubber is 1 or more and smaller than the dielectric constant of the dielectric of the antenna structure, the influence on the input impedance is smaller than that of the dielectric in the antenna structure. Adjustment is easy. In particular, when the relative dielectric constant of the dielectric rubber is sufficiently small (for example, about 1/10) relative to the dielectric constant of the dielectric in the antenna structure, the influence on the input impedance is almost eliminated. Even if it is installed, it is not necessary to adjust the input impedance again.
Further, when the dielectric rubber is projected from the surface of the radiation conductor, it can withstand not only the impact from the side of the antenna structure but also the impact from the surface of the antenna structure.
In addition, when the dielectric rubber is fixed to the circuit board on which the antenna structure is mounted, the dielectric rubber can be reliably prevented from being detached from the antenna structure.

1 is a perspective view of an antenna device according to the present invention. It is a perspective view for demonstrating an example of the attachment method of the dielectric rubber of the antenna apparatus of FIG. It is sectional drawing at the time of seeing the modification of the dielectric rubber in an antenna apparatus from the side. It is a top view which shows the example of mounting of the antenna device which concerns on this invention. It is sectional drawing at the time of seeing the antenna apparatus of FIG. 4 from the side surface. 1 is a perspective view of a digital camera according to the present invention. It is sectional drawing at the time of seeing the wristwatch concerning the present invention from the side.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the antenna device 1 according to the present invention includes an antenna structure 10 including a plate-like radiation conductor 11, a dielectric 12, a plate-like ground conductor 13, and a dielectric rubber 14. And a circuit board 15 for mounting the antenna structure 10. A feeding point 16 is provided in the approximate center of the antenna structure 10.

The radiating conductor 11, the dielectric 12 and the ground conductor 13 of the antenna device 1 are not particularly limited, but are rectangular or rectangular. The antenna device 1 has a structure in which a dielectric 12 is sandwiched between a radiation conductor 11 and a ground conductor 13 from the front and back.
The dielectric rubber 14 of the antenna device 1 is annular and endless as shown in FIG. That is, it has a square or rectangular hole 14a penetrating vertically in the center, and the outer shape is also square or rectangular and endless. In the antenna device 1, the dielectric rubber 14 is externally fitted to the dielectric 12. In this antenna device 1, the dielectric rubber 14 is annular and endless. However, the dielectric rubber 14 may be annular but cut at one or several places in the circumferential direction of the dielectric 12.
The main body of the circuit board 15 is formed of glass epoxy resin or the like. Substrate wiring (not shown) is formed on the circuit board 15. In addition to the antenna structure 10, a receiving circuit or a transmitting circuit is mounted on the circuit board 15.

  Here, the radiation conductor 11 and the ground conductor 13 are made of silver foil, metal plate, metal film, or the like having a predetermined thickness. The dielectric 12 is formed by laminating a number of ceramics having a predetermined thickness.

The dielectric rubber 14 is formed in a ring shape from a rubber material containing a dielectric material. The annular dielectric rubber 14 is provided in close contact with the side surface of the dielectric 12 of the antenna structure 10. In this case, it is preferable that the relative dielectric constant of the dielectric rubber 14 is larger than 1 and smaller than the relative dielectric constant of the dielectric 12. The relative dielectric constant can be adjusted by selecting a dielectric material or a rubber material and adjusting the amount of the dielectric material. In addition, as a rubber material of the dielectric rubber 14, it is preferable to use a material having a small dielectric loss tangent.
In this embodiment, the annular dielectric rubber 14 uses rubber (EPDM) as a base material. In order to arbitrarily set the relative dielectric constant, a high dielectric ceramic powder is contained in the rubber. It is formed by blending at an appropriately selected blending amount.

In particular, the relative dielectric constant of the dielectric rubber 14 will be described. The relative dielectric constant of the dielectric rubber 14 is preferably sufficiently smaller than the relative dielectric constant of the dielectric 12 (for example, about 1/10). Specifically, when incorporated in a wristwatch, the dielectric 12 has a relative dielectric constant of about 10 to 30, and therefore the dielectric rubber 14 preferably has a relative dielectric constant of about 1 to 3. The reason is as follows.
That is, when there is no difference between the relative permittivity of the dielectric 12 and the relative permittivity of the dielectric rubber 14, it is necessary to adjust the input impedance with the dielectric rubber 14 included. In this regard, if the dielectric constant of the dielectric rubber 14 is sufficiently small (for example, about 1/10) relative to the dielectric constant of the dielectric 12, the influence on the input impedance is reduced. There is no need to adjust the input impedance again.

Next, an example of a method for attaching the dielectric rubber 14 in the antenna device 1 according to the present invention will be described with reference to FIG.
FIG. 2 shows the antenna structure 10 mounted on the circuit board 15 and the dielectric rubber 14 before being attached. The dielectric rubber 14 is annular and endless. A double-sided tape 17 is attached to the lower surface of the dielectric rubber 14 via one adhesive surface.
From such a state, the hole 14a of the dielectric rubber 14 is pushed and expanded so as to be externally fitted to the dielectric 12 of the antenna structure 10, and the dielectric rubber 14 is connected to the ground conductor via the other adhesive surface of the double-sided tape 17. Paste to 13. In this way, the dielectric rubber 14 can be easily attached to the antenna structure 10.

  Since the dielectric rubber 14 has elasticity, it can be attached to the antenna structure 10 by using the elastic force of the dielectric rubber 14 itself without using the double-sided tape 16, but the dielectric rubber 14 from the antenna structure 10 can be attached. In order to surely prevent the separation, it is preferable that the grounding conductor 14 is adhered to the circuit board 15 with the double-sided tape 17 or an adhesive if the grounding conductor 14 is small.

Next, a modification of the dielectric rubber 14 used in the antenna device 1 according to the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view of a modification of the dielectric rubber in the antenna device as viewed from the side.
When viewed from the side, the dielectric rubber 14 in FIG. 3A has a structure in which the top surface is raised in a circular arc shape so that the top part comes to the center, and the top part protrudes from the surface of the radiation conductor 11. .
In addition, the dielectric rubber 14 in FIG. 3B has a structure in which, when viewed from the side, the upper surface is inclined so as to be narrowed upward, and the top portion protrudes from the surface of the radiation conductor 11. .
In addition, when viewed from the side, the dielectric rubber 14 in FIG. 3C has a structure in which the side is tapered so as to narrow toward the upper side, and the upper surface (top) protrudes from the surface of the radiation conductor 11. ing.
According to these modifications of the dielectric rubber 14, the top of the dielectric rubber 14 has a structure protruding from the surface of the radiation conductor 11, so that not only the impact from the side surface of the antenna structure 10 but also the antenna structure 10 can withstand an impact from the surface side.

Next, an example of mounting the antenna device 1 according to the present invention on the circuit board 15 will be described with reference to FIGS. 4 is a plan view showing an implementation example of the antenna device according to the present invention, and FIG. 5 is a cross-sectional view of the antenna device of FIG. 4 as viewed from the side.
The ground conductor 13 of the antenna structure 10 is provided over the entire surface of the circuit board 15. And the dielectric 12 with the radiation conductor 11 provided on the surface is affixed to the ground conductor 13 via a double-sided tape 17a.
A dielectric rubber 14 is provided on the surface of the circuit board 15 so as to surround the side surface of the dielectric 12. The dielectric rubber 14 is annular and endless. And this dielectric rubber 14 is affixed on the grounding conductor 13 via the double-sided tape 17b.
On the back surface of the circuit board 15, a ground wiring 18a, a signal wiring 18b, and the like are formed. The ground wiring 18 a is electrically connected to the ground conductor 13 through a conductor (not shown) of the through hole 15 a of the circuit board 15. On the other hand, the signal wiring 18 b is not electrically connected to the ground conductor 13.
In addition, a receiving IC (or transmitting IC) 19 or the like is provided on the back surface of the circuit board 15 so as to be connected to the signal wiring 18b. The signal wiring 18 b is electrically connected to the radiating conductor 11 via a power supply pin 16 a that penetrates the circuit board 15 and the dielectric 12.

According to the antenna device 1 according to the present invention described above, the following effects can be obtained.
First, since the elastic dielectric rubber 14 surrounds at least the periphery of the dielectric 12 in the antenna structure 10, the impact is absorbed or buffered by the dielectric rubber 14 when dropped. The damage of the dielectric 14 in the antenna structure 10 is prevented.
Second, since the annular dielectric rubber 14 is provided in close contact with the side surface of the dielectric 12, the amount of the annular dielectric rubber 14 is added to the antenna structure 10 as compared with the case of the dielectric 12 alone. Since the shape is substantially increased, the antenna gain is improved and the frequency band is increased. As a result, the reception sensitivity can be greatly improved.
Third, since the dielectric rubber 14 is fixed to the ground conductor 13 of the antenna structure 10, it is possible to reliably prevent the dielectric rubber 14 from being detached from the antenna structure 10.

Next, an electronic apparatus according to the present invention will be described with reference to FIG. FIG. 6 shows a perspective view of the digital camera.
The digital camera 100 has a built-in antenna device 1. The digital camera 100 is configured such that the antenna device 1 can transmit / receive captured image data or the like, or receive GPS (Global Positioning System) radio waves.
The digital camera 100 is not particularly limited, but the antenna device 1 is provided on the upper surface of the camera body 100A of the digital camera. The antenna structure 10 in the antenna device 1 is formed in a rectangular shape as a whole, and is provided so that a dielectric rubber 14 surrounds the side surface of the dielectric 12 of the antenna structure 10. The antenna device 1 is covered with a non-conductive protective cover 20.
Since the configuration of the antenna device 1 in this case is the same as that already described in the embodiment, detailed description thereof is omitted.

Another electronic apparatus according to the present invention will be described with reference to FIG. FIG. 7 shows a cross-sectional view of the wristwatch when viewed from the side.
The wristwatch 200 incorporates the antenna device 1. The wristwatch is configured such that the antenna device 1 can receive, for example, standard radio waves for time adjustment or GPS (Global Positioning System) radio waves.
In this wristwatch, although not particularly limited, the antenna device 1 is provided below the dial 21 in the watch body 200A.
That is, a through hole 10a is formed in the center of the antenna structure 10, and the minute hand shaft 23a and the hour hand shaft 23b from the timepiece module 22 extend upward through the through hole 10a. And the minute hand 24a and the hour hand 24b are attached to the part which protrudes from the upper surface of the antenna structure 10 in the minute hand axis | shaft 23a and the hour hand axis | shaft 23b.
The antenna structure 10 has a structure in which the radiating conductor 11 and the ground conductor 13 are short-circuited by a conductor 10b formed on the inner surface of the through hole 10a. In the antenna structure 10, power is supplied by the power supply pin 16 a at a position away from the center of the antenna structure 10. The antenna structure 10 is provided with a dielectric rubber 14 so as to surround the periphery of the side surface of the dielectric 12 of the antenna structure 10. The dielectric rubber 14 is bonded to the circuit board 15 with a double-sided tape (not shown).
Since the configuration of the antenna device 1 in this case is the same as that already described in the embodiment, detailed description thereof is omitted.

As mentioned above, although embodiment of this invention was described, it cannot be overemphasized that this invention is not limited to this embodiment and modification, Various deformation | transformation are possible.
For example, in the above embodiment, the dielectric rubber 14 is in close contact with the side surface of the dielectric 12, but may be in close contact with the side surface of the radiation conductor 11 or the side surface of the ground conductor 13 in addition to the dielectric 12. good.
For example, in the above-described embodiment, a digital camera or a wristwatch is used as the electronic device. However, the present invention can also be applied to other radio wave receiving devices such as a mobile phone and a GPS dedicated receiver. Furthermore, the present invention is not limited to receiving radio waves, but can be applied to transmitting radio waves.

DESCRIPTION OF SYMBOLS 1 Antenna apparatus 10 Antenna structure 11 Radiation conductor 12 Dielectric body 13 Ground conductor 14 Dielectric rubber 15 Circuit board 16 Feeding point 100 Digital camera 200 Wristwatch

Claims (5)

An antenna structure having a radiation conductor on the front side and a ground conductor on the back side across a dielectric;
A dielectric rubber that is in close contact with the dielectric and surrounds the periphery ,
The antenna device , wherein the dielectric rubber has a relative dielectric constant of 1 or more and is smaller than a relative dielectric constant of the dielectric . The dielectric rubber antenna device according to claim 1, characterized in that is in close contact with the side surface of the front Symbol dielectric. The antenna device according to claim 1 , wherein the dielectric rubber protrudes from a surface of the radiation conductor. The antenna device according to any one of claims 1 to 3 , wherein the dielectric rubber is fixed to a circuit board on which the antenna structure is mounted or the ground conductor. An electronic device comprising the antenna device according to any one of claims 1 to 4 in a device main body.

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