JP2006319734A - Strap with built-in antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a strap with a built-in antenna capable of effectively receiving a radio wave of a wider frequency band such as a radio wave for a television broadcast by being connected to a portable electronic device. <P>SOLUTION: The strap 1 with a built-in antenna is provided with a strap body 2 having a strap portion 2a formed in a circle by binding portions near both ends of a hollow string and the circle being formed so as to have a size enough to be hung from one part of a human body, and a coupling portion 2c for coupling the portable electronic device 11 to one part of the strap portion 2a; an external antenna 3 having a feeder element 3a connected to a ground conductor via a power supply of the portable electronic device 11 and a parasitic element 3b connected to the ground conductor of the portable electronic device 11, and arranged inside of the strap portion 2a; and a connection plug 5 for connecting the portable electronic device 11 to the external antenna 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a strap with a built-in antenna, and particularly relates to a strap with a built-in antenna that can be suitably used as an external antenna connected to a portable electronic device using wireless communication.

  2. Description of the Related Art Conventionally, cellular phones, PDAs (personal personal digital assistants) and other portable electronic devices using wireless communication (hereinafter simply referred to as “portable electronic devices”) have an antenna for receiving desired radio waves. ing. The shape and arrangement of this antenna are determined according to the frequency of received radio waves, reception sensitivity, and the like. For example, a current mobile phone using a frequency of 800 MHz to 2.4 GHz has a whip antenna extending outward from the casing and a built-in antenna disposed in the casing. The whip antenna and the built-in antenna allow the mobile phone to form space diversity and improve its reception sensitivity (see Patent Document 1).

  In addition, portable electronic devices with a built-in TV tuner are integrally formed with earphones or headphones used for portable electronic devices in order to receive radio waves for television broadcasting using a frequency of 470 to 770 MHz. An external antenna also serving as a ground line is used as a TV receiving antenna of the portable electronic device. The diversity antenna headphone as an example receives a desired television broadcast radio wave from the ground line of the speaker unit formed longer than the total length of the whip antenna of the portable electronic device or the built-in antenna, and also serves as the diversity antenna. It is possible to transfer the received electric signal of the radio wave to the portable electronic device connected to the headphone (see Patent Document 2).

JP-A-8-79152 JP 2003-163529 A

  However, the diversity antenna headphone connected to the portable electronic device simply uses the ground wire arranged from the connection plug to the earphone as a monopole antenna, thereby improving the gain of the antenna. It was difficult.

  In addition, since the diversity antenna headphone uses a monopole antenna formed only by the ground wire as an external antenna, it has only one resonance point determined at random, and has a wide frequency band such as radio waves for television broadcasting. It was difficult to efficiently receive radio waves to be used.

  Therefore, the present invention has been made in view of these points, and for television broadcasting by connecting to a mobile phone, a personal digital assistant (PDA) or other portable electronic device using wireless communication. An object of the present invention is to provide a strap with a built-in antenna that can effectively receive radio waves in a wide frequency band such as radio waves.

  Another object of the present invention is to provide a strap with a built-in antenna that can reduce the adverse effects of the opening angle of the strap portion and the human body as much as possible.

  In order to achieve the above-described object, according to one aspect of the strap with a built-in antenna of the present invention, a strap portion formed in an annular shape and a connecting portion for connecting a portable electronic device using wireless communication to a part of the strap portion. A strap body having a power supply element connected to the ground conductor via the power source of the portable electronic device, and a parasitic element connected to the ground conductor of the portable electronic device, A part or all of them are provided with an external antenna disposed inside the strap portion, and connected to one end of the external antenna, and provided with a connection plug for connecting the portable electronic device and the external antenna. It is characterized by being.

  As a result, the resonance point of the external antenna disposed inside the strap main body excellent in portability can be made two.

  Moreover, in the antenna built-in strap according to the present invention, as another aspect, the external antenna passes through the feeding element and the parasitic element from one end of the strap part that is formed in an annular shape by binding both ends of the strap part. By this, it is preferable that it is disposed inside the strap portion.

  This makes it possible to keep the arrangement interval between the feeding element and the parasitic element constant.

  Moreover, in the strap with a built-in antenna according to the present invention, as another aspect, the strap portion is preferably formed to have a size that can be used by being suspended from a wrist of a human body.

  This makes it possible to use the strap with a built-in antenna of the present invention away from the human torso.

  Moreover, in the antenna built-in strap of the present invention, as another aspect, the feeding element is formed to have a length obtained by multiplying the wavelength of the radio wave of the frequency used for the radio wave for digital terrestrial television broadcasting by 1/4. The parasitic element is a frequency used for radio waves for digital terrestrial television broadcasting, and has a length obtained by multiplying the wavelength of the radio wave at a frequency other than the frequency received by the feeder element by 1/4. Preferably it is formed.

  As a result, it is possible to provide two resonance points in the frequency band of the radio wave for digital terrestrial television broadcasting.

  Since the antenna built-in strap of the present invention is formed as described above, there is an effect that the reception band of the portable electronic device connected to the antenna built-in strap is widened.

  The strap with a built-in antenna according to the present invention has an effect that a constant reception sensitivity can always be obtained without depending on the opening angle of the strap portion.

  Furthermore, the strap with a built-in antenna according to the present invention has an effect that an adverse effect at the time of receiving a radio wave received from the torso of the human body is reduced.

  The strap with a built-in antenna according to the present invention has an effect of improving the reception sensitivity of radio waves for digital terrestrial television broadcasting.

  Hereinafter, embodiments of the strap with a built-in antenna according to the present invention will be described with reference to FIGS.

  Here, FIG. 1 shows one aspect of the embodiment of the strap with a built-in antenna of the present invention. FIG. 2 shows a state in which the antenna built-in strap of the present embodiment is suspended from the wrist of a human body. FIG. 3 shows a connection state between the external antenna of this embodiment and its peripheral portion. FIG. 4 shows the vicinity of the binding portion of the strap portion of this embodiment and the external antenna.

  As shown in FIG. 1, the strap 1 with a built-in antenna of the present embodiment includes a mobile phone, a PDA (personal personal digital assistant), and other portable electronic devices using wireless communication (hereinafter simply “portable electronic devices”). It is formed so that it can be connected to 11 and used. Specifically, the strap 1 with a built-in antenna has a strap body 2, an external antenna 3, and a connection plug 5, as shown in FIG.

  The strap main body 2 mentioned above has the strap part 2a, the binding part 2b, and the connection part 2c.

  The strap portion 2a of the strap body 2 is formed to be a flexible belt-like hollow string (strap) by weaving synthetic resin fibers. Further, as shown in FIG. 1, both ends 2d and 2e of the hollow strap portion 2a are formed in an annular shape by being bound by a binding portion 2b. As shown in FIG. 2, the annular strap portion 2 a is preferably formed to have a size that can be used by being suspended from the wrist R of the human body H.

  As shown in FIG. 1, the binding portion 2b that binds the vicinity of both ends 2d and 2e of the strap portion 2a is made of a synthetic resin having excellent mechanical characteristics such as ABS (acrylonitrile / butadiene / styrene copolymer) resin. It is formed in a box shape that is lightweight and excellent in impact resistance. Further, both ends 2d and 2e of the strap portion 2a are bound inside the binding portion 2b, and the portable electronic device 11 is connected to a position facing the strap portion 2a outside the binding portion 2b. A connecting portion 2c is formed.

  The connecting portion 2c is formed by ringing a tough synthetic resin fiber that does not break even when the portable electronic device 11 is connected. The annular connecting portion 2c has a length that can be inserted and connected to an L-shaped or U-shaped tunnel-shaped mounting hole 11b formed in the casing of the portable electronic device 11. Is formed.

  Further, as shown in FIG. 3, the external antenna 3 is formed to include a feeding element 3a and a parasitic element 3b.

  The power feeding element 3a is formed by using a covered wire covered with a highly conductive conductive wire such as aluminum or copper. The total length L1 of the power feeding element 3a is λ / 4 of the wavelength λ of the frequency (470 to 770 MHz) used for the radio wave for digital terrestrial television broadcasting, and one end thereof is connected to the connection plug 5. .

  As shown in FIG. 3, the parasitic element 3b is disposed in parallel with the feeder element 3a with a predetermined distance D. The parasitic element 3b is formed by using a covered wire coated with a conductive wire such as aluminum or copper like the feeder element 3a, and its full length L2 is used for radio waves for digital terrestrial television broadcasting. The frequency is λ / 4 of the wavelength λ of the radio wave having a frequency other than the frequency received by the power feeding element 3a. And, like the feed element 3 a, one end of the parasitic element 3 b is connected to the connection plug 5.

  The connection plug 5 is formed in a standardized shape such as a plug used for a rectangular connector for mobile phones (EIAJ RC-5240). As shown in FIG. 3, the connection plug 5 has a connection terminal 5a connected to the power feeding element 3a and a connection terminal 5b connected to the parasitic element 3b. These connection terminals 5a and 5b are connected to the ground conductor 19a via the power supply 19 of the portable electronic device 11 through the connection receptacle (connector on the portable electronic device side) 11a disposed in the portable electronic device 11. The feeding line 6a thus connected and the grounding line 6b connected to the grounding conductor 19a of the portable electronic device 11 are respectively connected.

  As shown in FIG. 4, the external antenna 3 connected to the connection plug 5 is inserted through the bundling portion 2b through the feeding element 3a and the parasitic element 3b from one end 2d of the hollow strap portion 2a. It is disposed inside the strap portion 2a.

  Note that a portion where the external antenna 3 is exposed to the outside from the binding portion 2b to the connection plug 5 is covered with a cylindrical protective cover 4 formed using an insulating synthetic resin.

  Next, the action of the antenna built-in strap 1 of the present embodiment will be described with reference to FIGS.

  Here, FIG. 5 shows an image external antenna generated in the external antenna of the present embodiment. FIG. 6 shows the VSWR characteristics of the external antenna of this embodiment. FIG. 7 shows a state in which the feeding element and the parasitic element of the external antenna according to the present embodiment are inserted from the two ends of the strap part.

  As shown in FIG. 1, the antenna built-in strap 1 of this embodiment can be connected to the mounting hole 11b of the portable electronic device 11 via the connecting portion 2c. The user of the connected portable electronic device 11 can carry the external antenna 3 without being particularly conscious.

  Further, as shown in FIG. 2, the annular strap portion 2a in which the external antenna portion 3 is provided is hung from the wrist R of the human body H, so that it is an obstacle to receiving a desired radio wave. The external antenna 3 can be moved away from the body B of the human body H, and the reception sensitivity of the external antenna 3 can be improved.

  As shown in FIG. 3, the external antenna 3 provided in the strap portion 2a includes a power feeding element 3a connected to the ground conductor 19a via the power source 19, and a parasitic element 3b connected to the ground conductor 19a. Therefore, a J-type antenna connected to the ground conductor 19a is formed. As a result, as shown in FIG. 5, the external antenna 3 connected to the ground conductor 19a has an image feeding element 3a ′ and an image parasitic element 3b that serve as an image antenna (image antenna) of the feeding element 3a and the parasitic element 3b. The image external antenna 3 having 'is imaged on the ground conductor 19a. Accordingly, the external antenna 3 has a parasitic element having a half-wavelength dipole antenna composed of the feeding element 3a and the image feeding element 3a ′ and a half-wavelength parasitic element composed of the parasitic element 3b and the image parasitic element 3b ′. An effect similar to that of a dipole antenna can be obtained.

  Here, FIG. 6 shows the VSWR characteristics of the external antenna 3 showing the effects as described above. The horizontal axis in FIG. 6 indicates the frequency (unit: MHz), and the vertical axis indicates the voltage standing wave rate (VSWR). This external antenna 3 has two resonance points in the vicinity of 470 MHz and 615 MHz, and the bandwidth Δf1 of VSWR <3.0 is 210 MHz (450 to 660 MHz (only the bandwidth including at least a part of 470 to 770 MHz is displayed). )). When VSWR <3.3, the bandwidth Δf2 is 593 MHz (442 to 1035 MHz). From this, it can be seen that the external antenna 3 is suitable for receiving broadband radio waves such as radio waves for terrestrial digital television broadcasting (470 to 770 MHz).

  As shown in FIG. 4, the external antenna 3 having such characteristics is disposed by inserting the feeding element 3a and the parasitic element 3b from one end 2d of the strap portion 2a. Even when the vicinity of 2b is opened by the opening angle θ, the arrangement interval D between the feed element 3a and the parasitic element 3b can be kept constant.

  As shown in FIG. 7, when the feeding element 3a is inserted from one end 2d of the strap portion 2a and the parasitic element 3b is inserted from the other end 2e of the strap portion 2a, the strap portion 2a opens. By opening by θ, the predetermined arrangement interval D changes to an arrangement interval D ′ having a length different from the arrangement interval D. Then, since the two resonance points of the external antenna 3 are affected, the reception band of the external antenna 3 is narrowed.

  On the other hand, the antenna built-in strap 1 of the present embodiment depends on the opening angle θ of the strap portion 2a by being disposed through the entire external antenna 3 from one end 2d of the strap portion 2a. In other words, a constant reception sensitivity is always obtained.

  From the above, the antenna built-in strap 1 of the present embodiment has an effect that the reception band of the portable electronic device 11 connected to the antenna built-in strap 1 is widened.

  In addition, the antenna built-in strap 1 of the present embodiment has an effect that a constant reception sensitivity is always obtained without depending on the opening angle θ of the strap portion 2a.

  Furthermore, the antenna built-in strap 1 of the present embodiment has an effect that the adverse effect at the time of radio wave reception received from the torso B of the human body H is reduced.

  And the antenna built-in strap of this embodiment has the effect that the reception sensitivity of the radio wave for terrestrial digital television broadcasting improves.

  In addition, this invention is not limited to embodiment mentioned above etc., A various change is possible as needed.

  For example, in the antenna built-in strap 1 of this embodiment, the length of the strap portion 2a is determined on the assumption that the strap portion 2a is suspended from the wrist R of the human body H. As an embodiment, as shown in FIG. 8, assuming that the strap portion 2 a is suspended from the neck N of the human body H, the length of the strap portion 2 a may be determined.

  Further, the antenna built-in strap 1 of the present embodiment is formed with the external antenna 3 as a digital terrestrial audio broadcasting antenna, but as another embodiment, has a frequency band different from the frequency band of the terrestrial digital audio broadcasting radio wave. The total lengths L1 and L2 of the feeding element 3a and the parasitic element 3b of the external antenna 3 may be changed so that the external antenna 3 can receive radio waves.

The top view which shows the one aspect | mode of embodiment of the strap with a built-in antenna of this invention The top view which showed the state which suspended the strap with a built-in antenna of this embodiment from the wrist of a human body The top view which shows the connection state of the external antenna of this embodiment, and its peripheral part The top view which shows the binding part vicinity and external antenna of the strap part of this embodiment The top view which shows the image external antenna produced in the external antenna of this embodiment The graph which shows the VSWR characteristic of the external antenna of this embodiment The top view which shows the state which each inserted the feed element and the parasitic element of the external antenna of this embodiment from the two ends of the strap part The top view which showed the state which suspended the antenna built-in strap of this embodiment from the neck of a human body

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Strap with built-in antenna 2 Strap body 2a Strap part 2b Bundling part 2c Connection part 2d, 2e End part of strap part 3 External antenna 3a Feeding element 3b Parasitic element 3p End part of feeding element 3g End part of parasitic element 3 'image (Image) External antenna 3a ′ Image feeding element 3b ′ Image parasitic element 4 Protective cover 5 Connection plug 5a (For feeding element) Connection terminal 5b (For parasitic element) Connection terminal 6a Portable electronic device side feeding line 6b Carrying 19 Electrical power supply side ground line 19 Power source 19a Grounding conductor D Disposition interval between feeding element and parasitic element Δf1 VSWR <3.0 bandwidth Δf2 VSWR <3.3 bandwidth

Claims (4)

A strap body having a strap portion formed in an annular shape and a connecting portion for connecting a portable electronic device using wireless communication to a part of the strap portion;
A power feeding element connected to a ground conductor via a power source disposed in the portable electronic device; and a parasitic element connected to the ground conductor; An external antenna disposed on the
A strap with a built-in antenna, comprising a connection plug formed to be connected to one end of the external antenna and connecting the portable electronic device and the external antenna. The external antenna is disposed inside the strap portion by inserting the feeding element and the parasitic element from one end of the strap portion formed in an annular shape by binding both ends of the strap portion. The strap with a built-in antenna according to claim 1, wherein the strap has a built-in antenna. The strap with a built-in antenna according to claim 1 or 2, wherein the strap portion is formed to have a size to be used by being suspended from a wrist of a human body. The feeding element is formed to have a length obtained by multiplying a wavelength of a radio wave of a frequency used for a radio wave for terrestrial digital television broadcasting by 1/4,
The parasitic element is formed with a length obtained by multiplying a wavelength of a radio wave having a frequency other than the frequency used for the radio wave for digital terrestrial television broadcasting and received by the feeder element by 1/4 The strap with a built-in antenna according to any one of claims 1 to 3, wherein the strap is built-in.

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