The present invention relates to a portable wireless device for communicating with other terminals.
Recently, for improved functionality, portable wireless devices provided with a communicating means built into a body thereof, for communication by means of RFID (Radio Frequency Identification), which is a contactless IC (Integrated Circuit) chip, and the like, are becoming common (for example, see Patent Document 1).
In addition, as shown in Patent Document 1, although portable wireless devices are generally provided with a retractable main antenna outside a body thereof, for communicating with a mobile communication network, portable wireless devices with a main antenna built into a body thereof, for a more sophisticated design, are becoming common recently.
Although the main antenna for communication and an antenna such as an RFID use different usable frequency bands, the antennas are disposed as far as possible from each other in order to suppress interference effects of the antennas with each other. This makes efficient use of space inside the body difficult.
The present invention has been made in view of the abovementioned problems, and one objective thereof is to provide a portable wireless device that allows for effective use of space inside the body while suppressing gain degradation of a plurality of antennas having different frequency bands disposed adjacently in the body.
In order to solve the above problems, the portable wireless device according to the present invention is characterized by including: a body; a first communication unit arranged in the body and including a first antenna unit that communicates with an external device by way of a first usable frequency band, and a first information processing unit that performs predetermined processing with respect to information communicated by the first antenna unit; a second communication unit arranged in the body and including a second antenna unit that is disposed in the vicinity of the first antenna unit and communicates by way of a second usable frequency band that is a frequency band overlapping a high-order secondary resonance point of the first usable frequency band, and a second information processing unit that performs predetermined processing with respect to information communicated by the second antenna unit; and a reducing unit for reducing a frequency component in the high-order secondary resonance point of the first usable frequency band.
Moreover, in the portable wireless device, it is preferable that the first antenna unit is a magnetic field antenna, and the reducing unit is a band limiting element, which is connected to the magnetic field antenna, and which exhibits high impedance in a frequency band relating to the high-order secondary resonance point.
In addition, in the portable wireless device, it is preferable that the first antenna unit is disposed so that at least a portion thereof faces the second antenna unit in a predetermined direction, and the band limiting element is connected to a portion of the first antenna unit facing the second antenna unit.
Furthermore, in the portable wireless device, the first communication unit is a contactless IC (Integrated Circuit) chip that communicates with an external device using electromagnetic induction or electromagnetic coupling.
Moreover, in order to solve the above problems, the portable wireless device according to the present invention is characterized by including: a body; a first communication unit arranged in the body and including a first antenna unit that communicates with an external device by way of a first usable frequency band, and a first information processing unit that performs predetermined processing with respect to information communicated by the first antenna unit; a second communication unit arranged in the body and including a second antenna unit that communicates by way of a second usable frequency band that is a frequency band overlapping a high-order secondary resonance point of the first usable frequency band and generated by resonance of the first usable frequency band, the second antenna unit being disposed at a position to an extent that interference with the first antenna unit would arise, and a second information processing unit that performs predetermined processing with respect to information communicated by the second antenna unit; and a reducing unit for reducing a frequency component in the secondary resonance point of the first usable frequency band, which is generated by resonance of the first usable frequency band.
In addition, in the portable wireless device, it is preferable that the first communication unit is arranged in the body and includes a third antenna unit that communicates with an external device by way of a third usable frequency band, and a third information processing unit that performs predetermined processing with respect to information communicated by the third antenna unit, and it is preferable that the reducing unit is connected to a portion of the first antenna unit and a portion of the third antenna unit, and reduces a frequency component in the high-order secondary resonance point of the first usable frequency band and a frequency component in a high-order secondary resonance point of the third usable frequency band.
According to the present invention, even if a plurality of antennas having different frequency bands are disposed adjacently in the body, influences due to interference between antenna gains are suppressed; therefore, it is possible to effectively utilize the space inside the body while maintaining the communication quality.
A description is provided hereinafter regarding an embodiment of the present invention.
The cellular telephone device 1 is configured to include an operation unit side body 2 and a display unit side body 3. The operation unit side body 2 is configured to include, on a front face 10 thereof, an operation button set 11 and a sound input unit 12 to which sounds, which a user of the cellular telephone device 1 produces during a phone call, are input. The operation button set 11 includes: feature setting operation buttons 13 for operating various settings and various features such as a telephone number directory feature and a mail feature; input operation buttons 14 for inputting digits of a telephone number and characters for mail; and a selection operation button 15 that performs selection of the various operations and scrolling.
The display unit side body 3 is configured to include, on a front face portion 20, a display 21 for displaying various information, and a sound output unit 22 for outputting sound of the other party of a conversation.
In addition, the abovementioned operation button set 11, the sound input unit 12, the display 21, and the sound output unit 22 compose a processing unit 62 to be described later.
Furthermore, an upper end portion of the operation unit side body 2 and a lower end portion of the display unit side body 3 are connected via a hinge mechanism 4. Moreover, the cellular telephone device 1 can be made into a state in which the operation unit side body 2 and the display unit side body 3 are opening each other (opened state), and into a state in which the operation unit side body 2 and the display unit side body 3 are closing each other (closed state), as the operation unit side body 2 and the display unit side body 3, connected via the hinge mechanism 4, pivot with respect to each other.
On the substrate 40, a device such as a CPU for performing predetermined arithmetic processing is mounted, and a predetermined signal is transmitted thereto when a user operates the operation button set 11.
The RFID portion 41 includes a magnetic field antenna 50 (a first antenna unit) for communicating with external devices by way of a first usable frequency band, and an RFID chip 51 (a first information processing unit) that performs predetermined processing with respect to information communicated by the magnetic field antenna 50. It should be noted that the RFID chip 51 is disposed on the substrate 40 facing the RFID portion 41 as shown in
The rear case portion 42 includes: a hinge mechanism fixing portion 42A for fixing the hinge mechanism 4; a main antenna housing portion 42B for housing a main antenna 70 (a second antenna unit), which communicates using a second usable frequency band that is higher than the first usable frequency band; a battery housing portion 42C for housing the rechargeable battery 43; and an RFID portion fixing portion 42D for fixing the RFID portion 41. It should be noted that the main antenna 70 is described later in detail.
The first communication unit 60 is composed of the RFID portion 41 and includes the magnetic field antenna 50 that communicates with external devices by way of the first usable frequency band (for example, 13.56 MHz), the RFID chip 51, and a capacitor 52 for adjustment.
The magnetic field antenna 50 includes a coil wound in a multiple spiral shape on a sheet made of PET (polyethylene terephthalate) material, and receives a signal of the first usable frequency band transmitted from external devices.
The RFID chip 51 includes: a power circuit 53 that generates a predetermined voltage based on electrical power induced by a signal received by the magnetic field antenna 50; an RF circuit 54 that performs signal processing such as modulation processing or demodulation processing with respect to a signal communicated by the magnetic field antenna 50; a CPU 55 that performs predetermined arithmetic processing; and memory 56 that stores predetermined data. The power circuit 53 is composed of a DC-DC converter, for example.
Here, behavior of the first communication unit 60 is described.
The magnetic field antenna 50, when approaching to within a predetermined distance to a reading/writing device disposed outside thereof, receives radio waves transmitted from the reading/writing device (modulated by a carrier frequency having the first usable frequency band (for example, 13.56 MHz)). It should be noted that, a predetermined adjustment (tuning) is made to the capacitor 52 so that the radio waves of the first usable frequency band are transmitted to the RF circuit 54 via the magnetic field antenna 50.
In addition, electromotive force is generated by an electromagnetic induction effect when the electromagnetic waves are received by the magnetic field antenna 50.
The power circuit 53 generates a predetermined power supply voltage from the electromotive force generated by the electromagnetic induction effect, and supplies the power supply voltage to the RF circuit 54, the CPU 55, and the memory 56. In addition, the RF circuit 54, the CPU 55, and the memory 56 are switched from a halt state to an active state when the predetermined power supply voltage is supplied from the power circuit 53.
The RF circuit 54 performs signal processing such as demodulation with respect to a signal of the first usable frequency band received via the magnetic field antenna 50, and transmits the processed signal to the CPU 55.
The CPU 55 writes or reads data to or from the memory 56, based on the signal received from the RF circuit 54. In a case of reading data from the memory 56, the CPU 55 transmits the data to the RF circuit 54. The RF circuit 54 performs signal processing such as modulation with respect to the data being read from the memory 56, and transmits the data to the external reading/writing device via the magnetic field antenna 50.
Furthermore, although the first communication unit 60 is described above to be of a so-called passive, induction field type (electromagnetic induction type) without a power source, the present invention is not limited thereto, and the first communication unit 60 can also be of a passive mutual induction type (electromagnetic coupling type) or a passive radiation field type (radio wave type), or an active type with a power source. In addition, an access method of the first communication unit 60 is described as a reading/writing type; however, the present invention is not limited thereto, and the access method can also be of a read-only type, a write-once type, and the like.
Moreover, as shown in
The main antenna 70 communicates with external devices by way of the second usable frequency band (for example, 800 MHz). It should be noted that, although 800 MHz is set as the second usable frequency band in the present embodiment, other frequency bands can also be used. In addition, the main antenna 70 can be configured as a so-called dual band compatible antenna that can accept, in addition to the second usable frequency band, a third usable frequency band (for example, 2 GHz), or as a multi-band compatible antenna that can further accept a fourth usable frequency band.
The communication processing unit 71 performs demodulation processing of a signal received by the main antenna 70 to transmit the processed signal to the processing unit 62, or performs modulation processing of a signal received from the processing unit 62 to transmit the processed signal to an external device via the main antenna 70.
As shown in
In addition,
As shown in
More specifically, the magnetic field antenna 50 has low-order and high-order secondary resonance points in cycles, other than the usable frequency band (13.56 MHz). In particular, when the high-order secondary resonance point (hereinafter referred to as high-order resonance point) overlaps the usable frequency band (800 MHz or the like) of the main antenna 70, the gain of the main antenna 70 is degraded (to be described later in detail with reference to
Given this, the cellular telephone device 1 according to the present embodiment adopts a configuration that reduces a frequency component in the high-order resonance point of the magnetic field antenna 50, in order to prevent interference with the main antenna 70 by a high-order resonance point of the magnetic field antenna 50, thereby avoiding the gain degradation of the main antenna 70.
More specifically, as shown in
Moreover, the band limiting element 80, in which the high-order resonance point of magnetic field antenna 50 has been adjusted to a constant that can be reduced, is added to the patterns (A1, A2 and A3).
Here, features of the band limiting element 80 are described. As shown in
Therefore, by providing the band limiting element 80 in the portion in which the magnetic field antenna 50 is in the vicinity of the main antenna 70, the frequency component in the high-order resonance point of the magnetic field antenna 50 is reduced, thereby reducing the influence due to the high-order resonance point of the magnetic field antenna 50 in the usable frequency band (high frequency band) of the main antenna 70. Moreover, since the band limiting element 80 is added to one side (A3 in
In addition, the band limiting element 80 may be configured with a ferrite core as shown in
Furthermore, the RFID portion 41 adjusts a resonance (tuning) frequency to 13.56 MHz based on a reactance value (L) of the magnetic field antenna 50 and the reactance value (C) of the capacitor 52. Here, the value L is determined by a size of the magnetic field antenna 50, the number of turns of the coil, the presence of material (a dielectric material or a magnetic material) provided therearound, or a distance from metal disposed in the vicinity thereof. Moreover, the value L of the magnetic field antenna 50 is dominant with respect to the high-order resonance point. However, according to the present embodiment, since the high-order resonance point can be reduced by adding the band limiting element 80 to a portion of the magnetic field antenna 50, the magnetic field antenna 50 can be freely designed regardless of a size thereof, the number of turns of the coil, the presence of material provided therearound, or a distance from metal disposed in the vicinity thereof.
In addition, since the stray capacitance of the band limiting element 80 is small (on the order of several pF), the usable frequency of the magnetic field antenna 50 is not affected.
In this way, in the cellular telephone device 1, since the high-order resonance point of the magnetic field antenna 50 is reduced by adding the band limiting element 80 to a portion in which one side of the antenna patterns of the magnetic field antenna 50 is the closest to the main antenna 70, the influence on the main antenna 70 due to the high-order resonance point of the magnetic field antenna 50 in the usable frequency band (800 MHz) can be reduced without affecting the usable frequency band (13.56 MHz) of the magnetic field antenna 50.
Moreover,
As can be seen from
Therefore, according to the present embodiment, by adding the band limiting element 80 to a portion in which one side of the antenna patterns of the magnetic field antenna 50 is the closest to the main antenna 70, the high-order resonance point of the magnetic field antenna 50 can be reduced (or disappeared), thereby making it possible to prevent influence on the usable frequency band of the main antenna 70, and to avoid gain degradation of the main antenna 70. Moreover, according to the present embodiment, the gain degradation of the main antenna 70 is reduced even if the magnetic field antenna 50 and the main antenna 70 are disposed to be adjacent; therefore, it is possible to effectively utilize the space inside the body and to achieve a size reduction of the body itself, while maintaining the communication quality and placing emphasis on design characteristics. Furthermore, in the present embodiment, since the band limiting element 80, which is integrated into the magnetic field antenna 50, is used as a wiring pattern of the magnetic field antenna 50 as a means for reducing the high-order resonance point of the magnetic field antenna 50, a separate member as the reducing unit is not required to be provided inside the body, thereby making it possible to effectively utilize the space inside the body and to achieve a size reduction of the body itself.
It should be noted that, in the aforementioned embodiment, although a case is assumed in which interference would arise since the main antenna 70 and the magnetic field antenna 50 are disposed to be adjacent, the present invention is effective for any case in which the influence due to the high-order resonance point of the magnetic field antenna 50 affects a usable frequency band of other antennas, regardless of a positional relationship between the antennas.
In addition, in the aforementioned embodiment, although the RFID is shown as a component for communicating with external devices by the first usable frequency band, it is not particularly limited thereto, and another component may be used as long as the component would cause interference with the usable frequency band of the main antenna 70.
Moreover, in order to provide two functions of a card function and a reading/writing function to a portable wireless device, a configuration is conceivable in which two antennas (a passive-type magnetic field antenna and an active-type magnetic field antenna) are arranged in the body; and even in such a configuration in which a plurality of antennas are arranged together with the main antenna 70 in the body, by integrally connecting the band limiting element 80 to each of the plurality of antennas, the frequency component in the high-order resonance point of each of the plurality of antennas can be preferably reduced, thereby making it possible to reduce the influence on the usable frequency band (high frequency band) of the main antenna 70 due to the high-order resonance point of each of the plurality of antennas. Here, the card function refers to a function to detect a passive-type magnetic field antenna from an external device side having a reading/writing function, thereby transmitting and receiving data; and the reading/writing function refers to a function to spontaneously detect an external device from an active-type magnetic field antenna side, thereby transmitting and receiving data.
In such a case in which the passive-type magnetic field antenna 50a and the active-type magnetic field antenna 50b are arranged in the vicinity of the main antenna 70 in the body, each high-order resonance point of the passive-type magnetic field antenna 50a and the active-type magnetic field antenna 50b may interfere with the usable frequency band of the main antenna 70; however, by connecting the single band limiting element 80 to both a portion of the passive-type magnetic field antenna 50a and a portion of the active-type magnetic field antenna 50b, the frequency component in the high-order resonance point of each of the passive-type magnetic field antenna 50a and the active-type magnetic field antenna 50b can be preferably reduced, thereby making it possible to reduce the influence on the usable frequency band (high frequency band) of the main antenna 70 due to the high-order resonance point of each of the plurality of antennas.
In addition, the band limiting element 80, which is integrally connected to a portion of the magnetic field antenna 50a and a portion of the magnetic field antenna 50b, makes it possible to reduce the frequency component in the high-order resonance point of each of the plurality of antennas in a collective manner; therefore, it is not required to separately provide a means for reducing the frequency component in the high-order resonance point for each of the plurality of antennas, thereby achieving greater efficiency of the space inside the body, reduction of the number of parts, and a size reduction of the body as a whole. It should be noted that the plurality of antennas are not limited to the two magnetic field antennas, and may be configured with more than two antennas of another kind.
Number | Date | Country | Kind |
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JP2007-087494 | Mar 2007 | JP | national |
This application is the U.S. National Stage application of PCT application PCT/JP2008/056200 filed on Mar. 28, 2008, which claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2007-087494, filed Mar. 29, 2007, and the contents of each of these applications are incorporated herein by reference in their entirety.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2008/056200 | 3/28/2008 | WO | 00 | 1/8/2010 |