JP2002237762A - transceiver - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the antenna gain when a portable device equipped with a wireless device is in a hand-held state or placed on a metal desk. SOLUTION: A Bluetooth adapter 106 which is a wireless device includes an upper connection portion 107 connected to an upper part of a main body of a mobile phone 101 which is a mobile device, and a mobile phone 101.
Connection part 1 connected to connector 105 at the bottom of the main body
08, a wireless circuit section 112 arranged along the rear face of the main body of the mobile phone 101 in a connecting section 109 connecting both connection sections on the rear face side of the main body of the mobile phone 101, and a radio circuit section 112 arranged in the lower connection section 110 Monopole antenna 11 having a built-in antenna element and having a radiation end extending below connector 110 toward the front side of main body of mobile phone 101.
4 is provided. Therefore, Bluetooth Adapter 1
06 and the mobile phone 101 to which it is attached, the gain of the built-in antenna element can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless device which is detachably mounted on a portable device such as a portable telephone.

[0002]

2. Description of the Related Art In recent years, a short-range high-speed wireless data communication system using Bluetooth has been proposed. This Bluetooth is available from Nikkei Electronics (19
No. 7.12, 1999, pp. 47 to 54), portable devices can be wirelessly connected at a data transmission rate of, for example, 1 Mbps. The operating frequency of Bluetooth is in the 2.45 GHz band, and the bandwidth is about 10
0 MHz.

[0003] Portable devices equipped with Bluetooth radios are not limited to notebook computers, but are also assumed to be cellular phones and digital still cameras. However, a notebook personal computer that can easily secure a relatively large space inside can incorporate a Bluetooth wireless device including an antenna, but a small portable device such as a mobile phone or a digital still camera has a built-in wireless device. It is difficult to secure space.

Therefore, as shown in, for example, Nikkei Electronics (Dec. 13, 1999, pp. 140 to 141), in a small portable device, Blu is externally provided.
There has been proposed a method of removably attaching the wireless device for Bluetooth via a connector. Bluetooth, which is detachably attached to a portable device via a connector as described above.
If the wireless device for wireless communication is referred to as a “Bluetooth adapter”, as this Bluetooth adapter,
For example, the one shown in FIG. 8 is assumed.

FIG. 8 is an external view showing the entirety of a Bluetooth adapter and a portable telephone as a portable device to which the Bluetooth adapter is attached. FIG. 8A is a partial perspective view of the front, and FIG.
(B) is a partial side perspective view. In FIG.
The Bluetooth adapter 801 includes an upper connection portion 803 that engages with an upper end surface of the mobile phone 802 and a mobile phone 8.
02 has a lower connecting portion 804 that engages with an end surface of a lower end portion thereof, and a connecting portion 805 that connects both connecting portions on the back side of the main body of the mobile phone 802, and has a substantially vertical cross-section that covers the back of the main body of the mobile phone 802. It is made of a U-shaped resin case.

[0006] A connector 806 is provided on the end face of the lower end of the portable telephone 802. A connector 807 that engages with the connector 806 to perform electrical connection is provided on a surface facing the lower connection portion 804 of the Bluetooth adapter 801 that engages with a lower end portion of the mobile phone 802.
As described above, the Bluetooth adapter 801 is mechanically fixed to the mobile phone 802 by fitting the connectors 806 and 807 of the lower connection portion 804 and the contact engagement of the upper connection portion 803, and is mounted.

[0007] As shown in FIG. 8, a circuit board 809 on which a wireless circuit 808 for Bluetooth is mounted is arranged along the rear surface of the main body of the portable telephone 802 in the connecting portion 805. In this case, the Bluetooth antenna 810 is connected to the lower connecting portion 804 on the circuit board 809.
It is assumed that it is arranged at a position close to. Note that 81
Reference numeral 1 denotes a mobile phone antenna, 812 a display unit, and 813 a battery unit.

[0008] In a wireless communication system, the antenna gain is an important factor affecting the communication quality.
In a system using Bluetooth, for example, Nikkei Electronics (No. 4.24, 2000, pp. 54-
As shown in 56), it is known that the antenna gain largely depends on the position of the built-in antenna.

Generally, a horizontal plane pattern averaging gain (hereinafter, referred to as “PAG”) in a state in which a user holds a mobile phone by hand and talks is used as an evaluation index of a mobile phone antenna.
Is used. When the user (human body) is arranged at the center of the spherical coordinate system and the head is arranged in the zenith (Z) direction, the PAG is given by Expression (1).

[0010]

(Equation 1)

In equation (1), Gθ (φ) and Gφ (φ) are the horizontal (XY plane) power directivity of the vertically polarized component and the horizontally polarized component, respectively. Also, XPR
Is the cross-polarization power ratio of the incoming wave incident on the antenna, that is, the power ratio of the vertical polarization component to the horizontal polarization component. Therefore, equation (1) means that the vertical polarization component is weighted by the cross polarization power ratio XPR and the power directivity in the horizontal plane is averaged.

A general cross polarization power ratio XPR in a multiplex environment of outdoor mobile communication such as a mobile phone system is as follows.
It is known to be between 4 and 9 dB. This is because the power of the vertical polarization component of the incoming wave is 4 to more than the power of the horizontal polarization component.
9 dB higher. In mobile phone systems,
This is because the main polarization of the antenna of the radio base station is fixed to the vertical polarization.

On the other hand, a short-range wireless communication technology called Blu
In ethos, there is no fixed radio base station,
It is not possible to predict at what angle each Bluetooth radio will be used. Therefore, the main polarization directions of various antennas are conceivable. In addition, since indoor use is mainly assumed, the influence of multipath from the wall surface is large, and it is assumed that the main polarization is not polarized in a certain direction. Therefore, here, the PAG in which the XPR value is set to 0 dB is used as an index for evaluating the gain of the Bluetooth antenna.

[0014]

Then, in the method of detachably mounting a Bluetooth wireless device outside the portable device via a connector, as shown in FIG. 8, a Bluetooth antenna 810 which is a built-in antenna is used.
Is located on the lower rear side of the mobile phone 802,
The antenna gain may decrease depending on the use condition. That is, since the lower end of the mobile phone 802 is where the user grips it with his / her hand, the radiation pattern changes under the influence of the hand to be gripped during use, and the user holds the mobile phone with his / her hand and the user (human body). PAG when placed in front of)
However, it is deteriorated by about 10 dB as compared with the free space.

When the cellular phone 802 is placed on a table, the back of the device is usually turned down. At this time, when the placed place is on a metal desk, the Bluetooth antenna 810 is very close to the metal desk, so that the Bluetooth
The radiation pattern of the antenna for use 810 changes, and the PAG deteriorates by about 7 dB as compared with the free space.

The present invention has been made in view of such circumstances, and improves the antenna gain when a portable device equipped with a wireless device as a Bluetooth adapter is in a hand-held state or placed on a metal desk. It is an object of the present invention to provide a wireless device having an antenna arrangement structure capable of performing the following.

[0017]

A wireless device according to the present invention for achieving the above object is used by being detachably mounted on a surface of a portable device placed on a desk, and when mounted, a wireless circuit section is provided. A wireless device to be arranged on the mounting surface side of the portable device, wherein the built-in antenna is supplied with power from the wireless circuit unit and an antenna radiation direction is a direction avoiding the mounting surface side of the mobile device. It is characterized by comprising an element.

In many cases, a portable device is used while holding the mounting surface, and the device is placed on a table with the mounting surface facing down.
At this time, the table to be placed may be made of metal. In these cases, in the present invention, the built-in antenna element
Since the radiation direction is arranged so as to be away from the mounting surface side of the portable device, when using the wireless device of the present invention and the entire portable device to which it is attached, When a portable device equipped with the wireless device of the present invention is placed on a metal object with the wireless device facing down, the radiation pattern of the built-in antenna element is less likely to be affected by hands or metal objects, and The gain can be improved.

A wireless device according to the present invention is a wireless device which is detachably mounted on a surface of a portable device placed on a desk and is used, and a first device mechanically connected to one end of the portable device. A connection portion, a second connection portion having a connector connected to a connector provided at the other end of the mobile device, and the first connection portion and the second connection portion on the mounting surface side of the mobile device. A wireless circuit portion disposed in the connecting portion along the placement surface side of the portable device, and a built-in antenna element disposed in the first connection portion or the second connection portion and supplied with power from the wireless circuit portion And characterized in that:

According to this wireless device, the location of the portable device in which the first connection portion and the second connection portion are engaged is a location surrounding the mounting surface side of the portable device. Is placed at a position avoiding the mounting surface side. Therefore, the radiation pattern of the built-in antenna element is less likely to be affected by a hand or a metal object in a hand-held state or a state placed on a metal object, and the gain of the built-in antenna element can be improved.

In the wireless device of the present invention, the built-in antenna element may be any one of a monopole antenna, an inverted F antenna, and a microstrip antenna, and the radiation end of the portable device faces the mounting surface from the mounting surface. Are arranged so as to extend toward the side surface of the.

According to the configuration of this radio, a relatively large arrangement space is required for the monopole antenna, the inverted F antenna, the microstrip antenna, and the like, but the arrangement space for these antennas can be secured. Therefore, the antenna gain can be improved, and an appropriate antenna according to the arrangement space can be used.

In the radio device according to the present invention, the built-in antenna element is a chip antenna, and a radiation surface thereof is arranged so as to face away from the placement surface of the portable device. I do.

According to this radio device, since the arrangement space can be small, the antenna gain can be improved, and
The size of the wireless device can be reduced.

In the wireless device of the present invention, the built-in antenna element is a one-wavelength loop antenna fed in a balanced manner, wherein a part of a loop in which a current contributing to radiation is distributed is formed on the surface of the portable device. Characterized in that it is arranged on the side face side facing the.

According to this radio, the loop antenna is
Part of the loop where the current contributing to radiation is distributed is located on the opposite side of the portable device at a position away from the mounting surface of the portable device, so it can be held in hand or on a metal object. In the placed state, the radiation pattern of the built-in antenna element is hardly affected by a hand or a metal object, and the gain of the built-in antenna element can be improved.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to FIGS. [First Embodiment] FIG. 1 is an external view showing the entirety of a wireless device according to a first embodiment of the present invention and a portable device to which the wireless device is attached. FIG. FIG. 1 (b)
It is a side part perspective view.

In FIG. 1, a portable telephone 101 as a portable device includes an antenna 102 which can expand and contract in a vertical direction, and a display unit 103 is provided on an upper front part of a main body.
A battery unit 104 is provided at a lower portion on the back side of the main body, and a connector 105 is provided on an end surface of a lower end portion.

Bluetooth, which is a wireless device detachably mounted on the back side of the main body of the mobile phone 101,
The adapter 106 has an upper connection portion 107 that engages with the upper end surface of the mobile phone 101, a lower connection portion 108 that engages with the lower end surface, and a connection portion 109 that connects the two connection portions. It is made of a resin case formed to have a substantially U-shaped vertical cross section so as to cover the back surface of 101. On a surface of the lower connection portion 108 facing the lower end portion of the mobile phone 101, a connector 110 that is fitted with the connector 105 and performs electrical connection is provided.

As described above, the Bluetooth adapter 106 is mechanically fixed to the mobile phone 101 by the fitting of the connectors 105 and 110 in the lower connection portion 108 and the contact engagement of the upper connection portion 107 so that the Bluetooth adapter 106 is mounted. Has become. Here, the battery unit 10 of the mobile phone 101
Circuit board 1 arranged in connecting portion 109 along the back surface on the four side
11 includes a matching circuit 113 in addition to a Bluetooth wireless circuit 112. Further, a monopole antenna 114 serving as a built-in antenna element is arranged in the lower connection portion 108.

The monopole antenna 114 is an inverted L antenna bent in a substantially L shape, and has a feeding end connected to the matching circuit 113 and a radiation end inside the lower connection portion 108 to avoid the back side of the main body. As shown in FIG. The monopole antenna 114 has, for example, a width of 3
The length is set to, for example, ／ wavelength (46 mm at 2.45 GHz) of the operating frequency.

Next, the operation of the Bluetooth adapter, which is a wireless device configured as described above, will be described with reference to FIGS. FIG. 2 is a diagram illustrating a state in which the wireless device (Bluetooth adapter) according to the first embodiment of the present invention and a portable device (mobile phone) to which the wireless device is attached are gripped by hand. FIG. 3 is a diagram illustrating a state in which a portable device (mobile phone) equipped with the wireless device (Bluetooth adapter) according to the first embodiment of the present invention is placed on a metal desk with the wireless device (Bluetooth adapter) down. .

As shown in FIG. 2, at the time of use, the user holds the lower end of the mobile phone 101 with the hand 201 for use. Then, the palm of the mobile phone 101 becomes flat on the back side of the main body, so that the circuit board 111 inside the Bluetooth adapter 106 is covered by the user's hand 201.

In this case, in the conventional example shown in FIG. 8, since the built-in antenna 810 is arranged on the circuit board 809,
The radiation direction of the built-in antenna 810 is covered by the user's hand 201. As a result, the radiation characteristics of the built-in antenna 810 and the user's hand 201 in close proximity to the built-in antenna 810 significantly deteriorate due to electromagnetic interaction. Specifically, the horizontal plane pattern averaging gain (PA
G) is a low value of about -17 dBd.

On the other hand, in the wireless device according to the first embodiment shown in FIG. 1, the monopole antenna 114 is disposed below the lower end of the portable telephone 101, which is a position avoiding the back side of the main body. The PAG is improved without being covered by the human hand 201. Specifically, the PAG in this case was about -13 dBd, which could be improved by about 4 dB.

Also, as shown in FIG.
When placed on the metal desk 301 with the th adapter 106 down, the circuit board 111 inside the Bluetooth adapter 106 is sandwiched between the metal desk 301 and the battery unit 104.

In this case, in the conventional example shown in FIG. 8, since the built-in antenna 810 is arranged on the circuit board 809,
The built-in antenna 810 is sandwiched between the metal desk 301 and the battery unit 104. As a result, the built-in antenna 81
The radiation characteristics of the antenna are significantly degraded due to the electromagnetic interaction between the zero and the metal table 301 and the battery unit 104 which are very close to the zero. Specifically, the horizontal plane pattern averaging gain (PAG) in this case has a low value of about −15 dBd.

On the other hand, in the wireless device according to the first embodiment shown in FIG. 1, since the monopole antenna 114 is disposed below the lower end of the mobile phone 101 at a position avoiding the back side, a metal desk is provided. The PAG is improved without approaching the battery 301 and the battery unit 104. Specifically, the PAG in this case was about -8 dBd, which could be improved by about 7 dB.

As described above, according to the first embodiment, the built-in antenna (monopole antenna 114) is arranged in the lower connection portion 108 below the lower end of the mobile phone 101, which is a position avoiding the back side. Therefore, the radiation end is not covered by the user's hand, and the influence of the metal table can be reduced. The antenna gain can be improved by about 4 to 7 dB in the state of being held by hand and placed on the metal table. become able to.

Although the inverted L-shaped antenna is shown as the monopole antenna in the first embodiment, for example, a linear inverted F-shaped antenna can be used in the same manner.
Although a monopole antenna is shown as the built-in antenna element, other microstrip antennas or plate-shaped inverted-F antennas using a plate-shaped element can be similarly arranged, and similar effects can be obtained. Can be

[Second Embodiment] FIG. 4 is an external view showing the entirety of a wireless device according to a second embodiment of the present invention and a portable device equipped with the wireless device. FIG. FIG. 4 (b) is a perspective view, partially in a side view.

In FIG. 4, a circuit board 402 inside the Bluetooth adapter 401 is larger in size than the circuit board 111 in FIG. Also, the lower connecting portion 4 of the Bluetooth adapter 401
03 is smaller than the lower connection portion 108 shown in FIG. 1 and assumes that there is no space below the connector 404 for arranging an antenna such as a monopole antenna that requires a certain space.

That is, as shown in FIG. 4, in the second embodiment, a chip antenna 405, which is a small antenna that does not require much mounting space, is provided with a radiation surface, It is arranged upward, and power is supplied from the wireless circuit 112 via the coaxial cable 406. The chip antenna 405 has a helical antenna formed inside a dielectric having a laminated structure. The chip antenna 405 is downsized (for example, about 8 mm in length, about 2 mm in width, and about 2 mm in height) by using a shortened wavelength in the dielectric. ) Was done.

Next, the operation of the Bluetooth adapter, which is a wireless device configured as described above, will be described with reference to FIGS. FIG. 5 is a diagram illustrating a state in which a wireless device (Bluetooth adapter) according to the second embodiment of the present invention and a portable device (mobile phone) to which the wireless device is attached are gripped by hand. FIG. 6 is a diagram illustrating a state in which a portable device (mobile phone) equipped with a wireless device (Bluetooth adapter) according to the second embodiment of the present invention is placed on a metal desk with the wireless device (Bluetooth adapter) down. .

In FIG. 5, since the chip antenna 405 is arranged in the upper connecting portion 107, the user's hand 2
01 and the PAG is improved. More specifically, the PAG in this case is about -13 dBd, which can be improved by about 4 dB as in the first embodiment.
In FIG. 6, the chip antenna 405 is disposed in the upper connection portion 107 and its radiation surface faces the upper direction of the mobile phone 101. Therefore, the influence of the metal desk 301 can be reduced, and the PAG can be improved. You. In particular,
The PAG in this case was about -11 dBd, which could be improved by about 4 dB.

As described above, according to the second embodiment, the built-in antenna (chip antenna 405) is arranged in the upper connection portion 107 in the upper part of the mobile phone 101, which is a position avoiding the back side of the main body. In addition, the radiation end of the antenna element can be prevented from being covered by the user's hand, and the influence of the antenna element when placed on a metal desk can be reduced. As a result, the antenna gain can be improved by about 4 dB.

It is preferable that the mobile phone antenna 102 and the chip antenna 405 be spaced apart from each other by a distance (for example, 10 mm) or more that does not cause deterioration in characteristics due to electromagnetic interaction. The arrangement of the chip antenna is not limited to the description of the present embodiment.
For example, the mobile phone 10 at a position avoiding the back side of the main body.
In some cases, a space for disposing the chip antenna can be ensured even in the lower connecting portion 403 below the lower end of 1.

[Third Embodiment] FIG. 7 is an external view showing the entirety of a wireless device according to a third embodiment of the present invention and a portable device to which the wireless device is attached. FIG. FIG. 7B is a perspective view partially showing a side view. As shown in FIG. 7, in the third embodiment, the Bluetooth adapter 7
01 is connected to Bl in the first embodiment.
It is formed to be approximately the same as or slightly larger than the lower connection portion 108 of the Bluetooth adapter 106, and a rectangular loop antenna 703 is disposed inside the lower connection portion 108.

The loop antenna 703 has both ends connected to the matching circuit 113 and its loop surface connected to the lower connecting portion 70.
2, it extends under the connector 110 toward the front of the main body so as to avoid the rear side of the main body. The loop antenna 703 is made of, for example, a copper wire having a diameter of about 1 mm, and its entire length is set to, for example, one wavelength of a working frequency (about 120 mm at 2.45 GHz). I have.

The loop antenna 70 thus configured
3 operates as a balanced-fed one-wavelength loop antenna. In this case, the current distributed on the circuit board 111 is reduced as compared with the antennas shown in FIGS. For this reason, in a state in which the user holds the hand as illustrated in FIG. 2, deterioration of radiation characteristics due to electromagnetic interaction between the hand and the circuit board 111 is reduced. The PAG in this state is about -11 dBd.

Further, a current contributing to radiation is distributed on a side 704 of the loop antenna 703 located far from the matching circuit 113. Therefore, as shown in FIG.
01 on the side of the metal table 30
Since it is not close to 1, radiation characteristics are improved.
The PAG in this state is about -7 dBd.

As described above, according to the third embodiment, the balanced one-wavelength loop antenna 7 which is a built-in antenna is used.
03, the mobile phone 10 at a position avoiding the rear side of the main body.
In the lower connection portion 702 below the lower end of the mobile phone 1, the loop surface is arranged so that the mobile phone 101 crosses from the rear side of the main body toward the front side of the main body, and the side 704 contributing to radiation of the loop antenna is connected to the mobile phone. Since it is arranged on the front side of the main body 101, it is possible to reduce the influence of the hand or the metal desk in the state of being gripped by hand and the state of being placed on the metal desk, and the antenna gain can be improved.

In the third embodiment, the loop antenna has a rectangular shape. However, the present invention is not limited to this. Even if the loop antenna has a circular shape or an elliptical shape, the current on the circuit board is similarly reduced. The distribution can be reduced, and a part of the loop in which the current contributing to radiation is distributed can be arranged on the front side of the mobile phone, and the same effect can be obtained.

Here, in each embodiment, the Bluetooth
Although the mobile phone is shown as a target to which the other adapter is detachably attached, this is a Bluetooth for mobile phone.
It is not intended to be limited to the other adapter. The wireless device of the present invention uses Bluetooth because it uses Bluetooth.
The present invention relates to an antenna arrangement for improving the gain of a built-in antenna in a wireless device that is detachably mounted on a portable device that requires an external wireless device.

That is, in the case of a portable device that requires an external Bluetooth radio device, the radio circuit board of the mounted radio device may be covered with the hand to be gripped when the device is gripped by hand. Further, when the wireless circuit board is placed on a metal desk with the wireless device facing down, the wireless circuit board may be arranged at a position close to the metal desk. In such a case, in such a case, the arrangement and configuration of the built-in antenna are set in the first to third embodiments so that the radiation pattern is hardly affected by the hand or the metal table.
This is the same as in the embodiment. Further, the wireless circuit boards may be collectively arranged on the bottom surface.

[0056]

As described above, according to the present invention,
When the wireless device of the present invention and the portable device on which it is mounted are gripped and used, or the portable device on which the wireless device of the present invention is mounted is placed on a metal object with the wireless device facing down Even in this case, the gain of the built-in antenna element can be improved.

[Brief description of the drawings]

FIG. 1 is an external view showing an entirety of a wireless device according to a first embodiment of the present invention and a portable device equipped with the wireless device, and FIG.
Fig. 1 is a partially transparent front view, and Fig. 1 (b) is a partially transparent side view.

FIGS. 2A and 2B are diagrams showing a state in which the wireless device according to the first embodiment of the present invention and a portable device equipped with the wireless device are gripped by hand, and FIG. 2A is a front view and FIG. ) Is a side view.

FIG. 3 is a diagram showing a state in which a portable device equipped with the wireless device according to the first embodiment of the present invention is placed on a metal desk with the wireless device facing down.

FIG. 4 is an external view showing the entirety of a wireless device according to a second embodiment of the present invention and a portable device equipped with the wireless device, and FIG.
FIG. 4B is a partial front view, and FIG. 4B is a partial side view.

5A and 5B are diagrams illustrating a state in which a wireless device according to a second embodiment of the present invention and a portable device equipped with the wireless device are gripped by hand, and FIG. 5A is a front view and FIG. ) Is a side view.

FIG. 6 is a diagram illustrating a state in which a portable device equipped with a wireless device according to a second embodiment of the present invention is placed on a metal desk with the wireless device facing down.

FIG. 7 is an external view showing the entirety of a wireless device according to a third embodiment of the present invention and a portable device equipped with the wireless device, and FIG.
Fig. 7 is a partially transparent front view, and Fig. 7 (b) is a partially transparent side view.

FIG. 8 is an external view showing the entirety of a conventional wireless device and a portable device to which the wireless device is attached, and FIG.
FIG. 8B is a partial side perspective view.

[Explanation of symbols]

Reference Signs List 101 Mobile phone (mobile device) 102 Antenna for mobile phone 103 Display unit 104 Battery unit 105 Connector 106, 401, 701 Bluetooth adapter (wireless device) 107 Upper connection unit 108, 403, 702 Lower connection unit 109 Connecting unit 110, 404 Connectors 111, 402 Circuit board 112 Radio circuit 113 Matching circuit 114 Monopole antenna 201 Hand 301 Metal table 405 Chip antenna 406 Coaxial cable 703 Loop antenna 704 Side

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Saito 2-45-1, Hikosancho, Kanazawa-shi, Ishikawa Pref. Inside Matsushita Communication Kanazawa Research Institute Co., Ltd. No.3-1, Matsushita Communication Industrial Co., Ltd. F-term (reference) 5K011 AA06 KA13 KA14 5K023 AA07 BB06 BB11 BB28 DD06 KK07 5K067 AA21 BB04 EE02 EE35 KK03 KK05 KK17

Claims (5)

[Claims] 1. A wireless device which is detachably mounted on a surface on which a portable device is placed on a desk and which is used, and when mounted, a wireless circuit section is arranged on the surface of the portable device. A wireless device, comprising: a built-in antenna element that is supplied with power from the wireless circuit unit and whose antenna radiation direction is a direction avoiding the placement surface side of the portable device. 2. A wireless device which is detachably mounted and used on a surface of a portable device placed on a desktop, wherein the first connecting portion is mechanically connected to one end of the portable device. A second connection portion having a connector connected to a connector provided at the other end of the portable device; and a built-in antenna element arranged in the first connection portion or the second connection portion and supplied with power from a wireless circuit portion. A wireless device characterized by the following. 3. The built-in antenna element is any one of a monopole antenna, an inverted F antenna, and a microstrip antenna, and has a radiation end directed from the mounting surface to the side surface of the portable device facing the mounting surface. The wireless device according to claim 1, wherein the wireless device is arranged so as to extend. 4. The built-in antenna element is a chip antenna, and a radiation surface thereof is disposed in a direction avoiding a placement surface side of the portable device. The wireless device according to claim 2. 5. The built-in antenna element is a one-wavelength loop antenna fed in a balanced manner, wherein a part of a loop in which a current contributing to radiation is distributed is on a side surface of the portable device facing the placement surface. The wireless device according to claim 1, wherein the wireless device is arranged so as to be located at a position indicated by the arrow.