WO2007099592A1

WO2007099592A1 - Antenna device and electronic device having the antenna device mounted thereon

Info

Publication number: WO2007099592A1
Application number: PCT/JP2006/303715
Authority: WO
Inventors: Kouji Watanabe
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2006-02-28
Filing date: 2006-02-28
Publication date: 2007-09-07

Abstract

Disclosed are an antenna device in which a communication sensitivity can be stabilized by setting a usable frequency band to a broad-band; and an electronic device having the antenna device mounted thereon. The antenna device comprises an antenna coil (11) connected to a communication control circuit (13) to be resonated, an antenna coil (12) stacked on the antenna coil (11) to be electrically isolated therefrom, and a resistor (14) connected to the antenna coil (12). The resistance value of the resistor (14) is set so that the Q-value of the antenna coil (12) is larger than the Q-value of the antenna coil (11).

Description

Specification

Antenna device and electronic device equipped with the same

Technical field

The present invention relates to an antenna device used for wireless communication and an electronic device equipped with the antenna device.

Background art

In recent years, with the spread of non-contact communication systems in which a reader / writer communicates with a mobile device, a wireless tag, an IC card or the like and a reader / writer in a non-contact manner, a non-contact communication system providing stable communication sensitivity is provided. It is requested from the field.

[0003] As a conventional antenna device for noncontact communication, one having a double loop structure in which an outer conductive loop and an inner conductive loop are formed concentrically to improve power efficiency is known. (See, for example, Patent Document 1). Furthermore, as a conventional double-loop antenna device, there is also a device in which two rhombus-shaped loop antennas are disposed on the same plane (see, for example, Patent Document 2).

[0004] Further, as a conventional antenna device, there is one in which electrical characteristics of the antenna coil are changed to extend a communication distance by arranging two identical antenna coils in an overlapping manner.

Patent Document 1: Japanese Patent Application Laid-Open No. 2001-292018

Patent Document 2: Japanese Patent Application Laid-Open No. 2002-84123

Disclosure of the invention

Problem that invention tries to solve

[0005] While the conventional antenna device can extend the communication distance long, the available resonance frequency in non-contact communication is narrowed, so that there is a problem that various services can not be supported. . Specifically, in a non-contact communication system provided for each service such as a ticket gate path or electronic money, since the usable resonance frequency for each service is different, various conventional antenna devices having a narrow resonance frequency are used. Can not respond to Further, since the frequency that can be received by an information processing device such as a reader / writer may be individually different, the conventional antenna device having a narrow usable frequency may communicate with various information processing devices. There is a problem that can not be done.

The present invention has been made to solve the conventional problems, and provides an antenna device capable of stabilizing communication sensitivity by broadening the usable frequency band and providing an electronic device equipped with the antenna device. It is a thing.

Means to solve the problem

The antenna device of the present invention comprises a first antenna coil that causes resonance in a connected circuit and

A second antenna coil disposed in an overlapping manner (insulated) on the first antenna coil, wherein a Q value of the second antenna coil is larger than a Q value of the first antenna coil; Have a configuration.

With this configuration, communication characteristics are changed by arranging the first antenna coil and the second antenna coil having a Q value larger than the Q value of the first antenna coil so as to change communication characteristics. Communication sensitivity can be stabilized by making the usable frequency band as wide as it is.

Further, in the antenna device of the present invention, a resistance is provided to the second antenna coil, and a resistance value of the resistor is determined such that a Q value of the second antenna coil is a Q value of the first antenna coil. It has a configuration that is set to a larger value.

With this configuration, if the resistance value of the second antenna is reduced so that the Q value of the second antenna coil is larger than the Q value of the first antenna coil, the power consumption is increased and the communication in the first antenna is performed. Because the characteristics change, the communication sensitivity can be stabilized by widening the usable frequency band while keeping the communication distance long.

[0010] Further, the antenna device of the present invention has a configuration in which one of the loops constituting the second antenna coil is opened.

With this configuration, by arranging the first antenna coil and the second antenna coil in which one of the loops is open, the current does not flow to the second antenna coil, and the communication characteristic is associated with capacitive coupling etc. Because of this change, it is possible to widen the available frequency band while keeping the communication distance longer. [0011] In the antenna device of the present invention, the number of loops constituting the second antenna coil, the line width of the loop, and the spacing of the loops may be determined according to the first Q value of the second antenna coil. Set to be larger than the Q value of the antenna coil, and have a configuration! /.

With this configuration, since the communication characteristics change, the communication sensitivity can be stabilized by widening the usable frequency band while the communication distance is extended.

The electronic device of the present invention has a configuration in which the antenna device of the present invention is mounted.

With this configuration, the communication sensitivity of the electronic device can be stabilized by widening the usable frequency band while keeping the communication distance long.

Effect of the invention

As described above, according to the present invention, it is possible to provide an antenna device capable of stabilizing communication sensitivity by widening a usable frequency band, and an electronic device equipped with the antenna device.

Brief description of the drawings

FIG. 1 is a view for explaining the configuration of an antenna device according to a first embodiment of the present invention. FIG. 2 is a distance at which the antenna device can communicate with an information processing device by changing the resonance frequency. Graph that measured

[FIG. 3] A diagram for explaining the configuration of the antenna device according to the second embodiment of the present invention. [FIG. 4] The distance at which the antenna device can communicate with the information processing device was measured by changing the resonance frequency. Graph

[FIG. 5] An information processing apparatus using the antenna device according to the first embodiment of the present invention having various resistances and using the antenna device according to the second embodiment of the present invention Graph which measured distance which we can communicate with

Explanation of sign

Ten and twenty antenna devices

11, 12, 22 antenna coils

13 Communication control circuit BEST MODE FOR CARRYING OUT THE INVENTION

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

(First Embodiment of the Present Invention)

An antenna device according to a first embodiment of the present invention will be described. FIG. 1 is a diagram for explaining the configuration of an antenna apparatus according to a first embodiment of the present invention.

For example, the antenna device 10 is mounted on an electronic device such as a mobile phone or an IC card, and communicates with an information processing device such as a noncontact reader / writer. Note that, using the electronic device and the information processing device in which the antenna device 10 is mounted, services such as a ticket pass and electronic money are provided.

The antenna device 10 is configured of an antenna coil 11 and an antenna coil 12 formed of loop-shaped conductors, and a communication control circuit 13 for controlling communication of the antenna device 10.

[0020] The antenna coil 11 and the antenna coil 12 are approximately the same size, electrically isolated, and in fact arranged so as to overlap each other. In addition, the antenna coil 11 is connected to the communication control circuit 13 and runs!

Communication control circuit 13 is formed of, for example, a non-contact IC or a resonance circuit having a capacitor (not shown), and interacts with antenna coil 11 to cause resonance at a specific frequency. It! / Scold.

The antenna coil 12 is provided with a resistor 14, and the resistance value of the resistor 14 is set to a value such that the Q value of the antenna coil 12 is larger than the Q value of the antenna coil 11. . When the resistor 14 is a variable resistor, the Q value of the antenna coil 12 can be controlled according to the setting of the resistance value of the resistor 4. Here, the Q value is a value representing the state of vibration, and the larger the value is, the slower the energy dissipation is.

Here, FIG. 2 shows a graph in which the distance at which the antenna device 10 can communicate with the information processing device is measured by changing the resonance frequency. In FIG. 2, two cases of measurement by the conventional antenna device of the antenna coil alone and measurement by the antenna device 10 are illustrated.

As shown in FIG. 2, the communication characteristic of the antenna device 10 can communicate over a longer distance than the communication characteristic of the conventional antenna device of a single antenna coil, and the resonance frequency band can be obtained. It can be seen that For example, in the case of a contactless communication system provided for each ticket pass or service such as electronic money, the power antenna device 10 has different resonance frequencies such as 13.42 MHz and 13.56 MHz. Any service can communicate over a long distance.

As described above, in the antenna device according to the first embodiment of the present invention, the antenna coil 11 and the antenna coil 12 are disposed so as to overlap with each other, and the Q value of the antenna coil 11 causes the antenna coil 12 to If the resistance value of antenna 12 is decreased to increase the Q value of Q, the power consumption increases and the communication characteristics of antenna 11 change, so the usable frequency band can be made wide while the communication distance is extended. it can.

In addition, even if the resonance frequency used for each ticket pass and service such as electronic money is different, or the frequency that can be received by an information processing device such as a reader / writer is individually different, the present invention When the antenna device according to the first embodiment is used, the usable frequency band is a wide band, so that communication sensitivity can be stabilized.

Second Embodiment of the Present Invention

An antenna apparatus according to a second embodiment of the present invention will be described. FIG. 3 is a view for explaining the configuration of an antenna apparatus according to a second embodiment of the present invention. In FIG. 3, the same components as those constituting the antenna apparatus according to the first embodiment of the present invention are designated by the same reference numerals, and the description thereof will be omitted.

The antenna device 20 is, similarly to the antenna device 10, mounted on an electronic device such as a mobile phone or an IC card, and is configured to communicate with an information processing device such as a contactless reader / writer. The antenna device 20 is configured of an antenna coil 11 and an antenna coil 22 formed of loop-shaped conductors, and a communication control circuit 13 that controls communication of the antenna device 20.

[0029] Antenna coil 11 and antenna coil 22 have substantially the same size, are electrically insulated, and are in fact arranged to overlap each other. Note that one of the loops constituting the antenna coil 22 is open.

Here, FIG. 4 shows a graph in which the distance at which the antenna device 20 can communicate with the information processing device is measured by changing the resonance frequency. In Figure 4, a conventional antenna coil alone is Two cases of measurement by the antenna device and measurement by the antenna device 20 are illustrated.

As shown in FIG. 4, the communication characteristic of the antenna device 20 has a wider resonance frequency band in the state where communication can be performed over a longer distance than the communication characteristic of the conventional antenna device of a single antenna coil. I understand. For example, in the non-contact communication system provided for each ticket pass or electronic money service, the antenna devices 20 having different resonance frequencies, such as 13.42 MHz and 13.56 MHz, may be used. It can also communicate over long distances in

As described above, in the antenna device according to the second embodiment of the present invention, current is supplied to the antenna coil 22 by arranging the antenna coil 11 and the opened antenna coil 22 so as to overlap with each other. Since communication characteristics change with non-flow and capacitive coupling etc., the usable frequency band can be made wide while the communication distance is extended.

Here, FIG. 5 shows a graph in which the distance that can be communicated with the information processing device is measured in the case of using the antenna device 10 having various resistances and in the case of using the antenna device 20. In the results shown in FIG. 5, the antenna device 20 is optimum, and the antenna device 10 having a resistance of 15 kQ is optimum among the antenna devices 10.

In the embodiment of the present invention, the number of loops constituting antenna coil 12 or antenna coil 22, the line width of the loop, and the spacing of the loops are the same as the Q factor of antenna coil 12 or antenna coil 22. May be set to be larger than the Q value of the antenna coil 11, respectively.

Industrial applicability

As described above, according to the present invention, an antenna device used for wireless communication and an electronic device equipped with the antenna device have an effect of enabling communication sensitivity to be stabilized by widening the usable frequency band. It is useful for equipment etc.

Claims

The scope of the claims

[1] A first antenna coil causing resonance in a connected circuit,

And a second antenna coil disposed to overlap the first antenna coil,

An antenna device characterized in that the Q value of the second antenna coil is larger than the Q value of the first antenna coil.

[2] A resistor is provided to the second antenna coil,

The resistance value force of the said resistance is set to the value which becomes larger than Q value of a said 1st antenna coil, and Q value of a said 2nd antenna coil is an antenna apparatus of Claim 1 characterized by the above-mentioned.

[3] The antenna device according to claim 1, wherein one of the loops constituting the second antenna coil is open.

[4] The Q value of the second antenna coil is larger than the Q value of the first antenna coil in the number of loops constituting the second antenna coil, the line width of the loops, and the spacing of the loops. The antenna device according to claim 1, wherein the antenna device is set as follows.

[5] An electronic apparatus comprising the antenna device according to claim 1 mounted thereon.