JP4918428B2 - Antenna device and portable radio - Google Patents

Description

  The present invention relates to an antenna device capable of communication using a plurality of communication frequency bands, and a portable wireless device using the antenna device.

  In recent years, for example, portable wireless devices such as mobile phones have been miniaturized, and accordingly, small antennas are also required.

  In addition to recent wireless communication used for calling and sending / receiving e-mails, portable wireless devices in recent years, for example, television broadcast reception, Bluetooth communication, wireless LAN communication, and short distances from external devices such as security keys In order to perform wireless communication, a plurality of wireless communication applications have been provided. In order to simultaneously operate the plurality of wireless communication applications, it is necessary to provide a separate antenna element in the portable wireless device for each wireless communication application.

  However, it is expected that more and more wireless communication applications will be installed in portable wireless devices in the future, and if separate antenna elements must be provided for each wireless communication application, the size and weight of portable wireless devices will be reduced. It becomes difficult. Therefore, there is a demand for a small and lightweight antenna device that can simultaneously operate a plurality of wireless communication applications, and a portable wireless device using the antenna device.

  As an example of a conventional antenna device, an antenna element is provided with a plurality of power feeding sections, and when one is selected and fed, the other feeding section is connected to a predetermined impedance to switch the resonance frequency It has been known. In the antenna having such a configuration, an unnecessary power feeding unit and a part of unnecessary elements can be electrically disconnected (see, for example, Patent Document 1).

  As another example of a conventional antenna device, an antenna device configured to switch between a feeding portion and an open end portion of an antenna element is known. With the antenna having such a configuration, directivity diversity and polarization diversity effects can be obtained (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 11-163620 International Publication No. 02/039544 Pamphlet

  However, although the conventional antenna disclosed in Patent Document 1 supports a plurality of frequency bands, only one resonance frequency can be obtained at a certain time in order to selectively switch the feeding point of the antenna. Therefore, a plurality of wireless communication applications cannot be operated simultaneously.

  With the conventional antenna disclosed in Patent Document 2, different current distributions can be formed even with a single antenna element by switching between the feeding part and the open end, but it cannot cope with a plurality of frequency bands. Further, since the power feeding unit and the open end are switched, they cannot be operated simultaneously.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a small antenna device capable of simultaneously operating a plurality of wireless communication applications, and a portable wireless device using the antenna device.

To achieve the above object, the antenna device of the present invention provides an antenna device for communicating signals of a plurality of communication frequency bands including a first communication frequency band and the second communication frequency band, the A first wireless unit that communicates a signal in one communication frequency band, a second wireless unit that communicates a signal in a second communication frequency band, and the first wireless unit in the first communication frequency band. A first duplexer connected to be energized and connected to the second radio unit so as to be energized in the second communication frequency band, a first reactance circuit having one end grounded, and the first communication A second reactance circuit that cuts off a frequency band and passes the second communication frequency band; and a first reactance circuit having one end connected to the duplexer and the other end connected to one end of the second reactance circuit An antenna element and one end of the second rear It is connected to the other end of the chest circuit, a second antenna element and the other end is connected to the other end of the first reactance circuit, the third wireless unit for communicating signals of the third communication frequency band And connected to one end of the first reactance circuit in the second communication frequency band so as to be energized, and in the third communication frequency band, the third communication is connected to the second antenna element. The second antenna element is connected to the first reactance circuit via the second duplexer, and connected to the first reactance circuit. In the communication frequency band, the first antenna element operates as a first monopole antenna, and in the second communication frequency band lower than the first communication frequency band, the first antenna element and the first antenna element With two antenna elements In the third communication frequency band that is lower than the first communication frequency band and different from the second communication frequency band, the second antenna element serves as a second monopole antenna. Work .

With this configuration, it is possible to provide a small antenna device that can simultaneously operate a plurality of wireless communication applications. Further, it is possible to provide a small antenna device that can simultaneously operate a plurality of wireless communication applications equal to or more than the number of antenna elements. Furthermore, it is possible to perform communication with different antenna configurations for each frequency band.

Further, the antenna device of the present invention, the third communication frequency band, and equal configuration to the first communication frequency band.

  With this configuration, the first antenna element and the second antenna element each operate as a monopole antenna in the first communication frequency band, and the first antenna element together with the second antenna element in the second communication frequency band. Since it operates as a loop antenna, a small antenna device that can simultaneously operate a plurality of wireless communication applications can have a diversity configuration in the first frequency band.

Further, the antenna device of the present invention, the first reactance circuit has a configuration with a variable capacitor.

  With this configuration, in a small antenna device that can simultaneously operate a plurality of wireless communication applications, for example, high antenna performance can be obtained according to a channel used for a certain wireless communication application.

Further, the antenna device of the present invention, the first reactance circuit comprises a plurality of reactance elements are selected from the plurality of reactance elements according to the frequency to be used among the plurality of communication frequency bands It is configured.

  With this configuration, in a small antenna device that can simultaneously operate a plurality of wireless communication applications, for example, high antenna performance can be obtained according to a channel used for a certain wireless communication application.

  Moreover, the 1st portable radio of this invention has a structure provided with one of the said antenna devices.

  With this configuration, it is possible to provide a small portable wireless device that can simultaneously operate a plurality of wireless communication applications.

  ADVANTAGE OF THE INVENTION According to this invention, the small antenna apparatus which can operate a some radio | wireless communication application simultaneously, and a portable radio | wireless machine using the same can be provided.

  Hereinafter, an antenna device and a portable wireless device according to an embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram showing an example of the configuration of an antenna device 1 according to the first embodiment of the present invention. Here, for example, the antenna device 1 is described as corresponding to the communication frequency band of the Bluetooth 2.4 GHz band of Bluetooth as the first communication frequency band and the 400 MHz band of the security key system as the second communication frequency band. You may make it respond | correspond to frequency bands other than this.

  The antenna device 1 includes a first antenna element 11, a second antenna element 12, a first reactance circuit 13, a second reactance circuit 14, a duplexer (or switching circuit) 15, a 2.4 GHz band A radio unit 16 and a 400 MHz band radio unit 19 are provided. Reference numeral 23 denotes a ground pattern having a ground potential, and is constituted by a conductor pattern on a circuit board, for example.

  One end of the second antenna element 12 is grounded via the first reactance circuit 13. One end of the first antenna element 11 is connected to the other end of the second antenna element 12 via the second reactance circuit 14. The other end of the first antenna element 11 is configured to be connected to the radio unit 16 and the radio unit 19 via a duplexer (or switching circuit) 15 so as to be energized.

  The duplexer 15 is set so that the 2.4 GHz band passing loss between the ports to which the first antenna element 11 and the radio unit 16 are connected is small and the isolation is high in the 400 MHz band. In addition, the transmission loss in the 400 MHz band between the ports to which the first antenna element 11 and the radio unit 19 are connected is small, and the isolation is set to be high in the 2.4 GHz band. Further, the ports to which the wireless unit 16 and the wireless unit 19 are connected are set so as to have high isolation.

  The second reactance circuit 14 is connected to one end of the first antenna element 11 and the other end of the second antenna element 12, and FIG. 2 is a diagram showing a specific example thereof. FIG. 4A shows an inductor 14A, and FIG. 4B shows a parallel resonant circuit of an inductor 14A and a capacitor 14B. The inductance of the inductor 14A and the capacitance of the capacitor 14B are set to have sufficiently high impedance in the 2.4 GHz band and sufficiently low impedance in the 400 MHz band.

  At this time, the first antenna element 11 and the second antenna element 12 are cut off at a high frequency by the second reactance circuit 14 in the 2.4 GHz band, and at a high frequency through the second reactance circuit 14 in the 400 MHz band. Is conducted.

  The first antenna element 11 is set to an electrical length of about a quarter wavelength in the 2.4 GHz band.

  The first reactance circuit 13 is, for example, a capacitor 13, and its capacitance is set according to the electrical length of the second antenna element 12. Specifically, the inductance determined by the loop-like total electrical length composed of the first antenna element 11, the second reactance circuit 14, the second antenna element 12, and the ground pattern 23 and the capacitance of the capacitor 13 are 400 MHz band. Is set so as to obtain the resonance.

Next, the operation of the antenna device 1 will be described.
In the antenna device 1, the first antenna element 11 operates as a monopole antenna in the 2.4 GHz band.

  Further, the antenna device 1 operates as a loop antenna at 400 MHz by the first antenna element 11, the second reactance circuit 14, the second antenna element 12, the ground pattern 23, and the capacitor 13 as a tuning capacitor.

  Further, in the antenna device 1, for example, the 2.4 GHz band Bluetooth and the 400 MHz band security key system can be operated simultaneously by the duplexer 15.

  In addition, it is desirable in terms of antenna performance that the first antenna element 11 or the second antenna element 12 and the ground pattern 23 be configured to be separated as much as possible. Thereby, high radiation resistance can be obtained and high radiation efficiency can be obtained. Further, it is desirable in terms of antenna performance that the loop opening surface is orthogonal to the surface of the ground pattern 23. Thereby, high radiation resistance can be obtained and high radiation efficiency can be obtained.

  As described above, according to the antenna device 1, the first antenna element operates as a monopole antenna in the first communication frequency band, and the first communication element in the second communication frequency band lower than the first communication frequency band. Since the antenna element operates as a loop antenna together with the second antenna element, a small antenna device capable of simultaneously operating a plurality of wireless communication applications can be provided.

  In the present embodiment, the case where the first communication frequency band is the 2.4 GHz band and the second communication frequency band is the 400 MHz band has been described, but each communication frequency band is not limited to the above, If the communication frequency band is a frequency band lower than the first communication frequency band, the same effect can be obtained by appropriately setting the frequency characteristic of the second reactance circuit 14.

  Further, the shape of the first antenna element 11 and the second antenna element 12 is not limited to a linear shape, and may be, for example, an L shape, a meander shape, or an appropriate curved shape, and the ground pattern 23. It is not necessary to form on the same plane.

  In the above description, the wireless unit 16 is described as a Bluetooth 2.4 GHz wireless unit for Bluetooth, but a 2.4 GHz wireless unit for wireless LAN may be used. In the above description, the wireless unit 19 is described as a 400 MHz band wireless unit for a security key system. However, a 400 MHz band wireless unit for digital television broadcasting (DTV) may be used.

  Further, as in the antenna device 2 shown in FIG. 3, a Bluetooth 2.4 GHz band radio unit 16 and a wireless LAN 2.4 GHz band radio unit 17 are switched to a switching circuit 18 such as a SPDT (Single Pole Double Throw) switch. If it is configured to be connected to the duplexer 15 via a wireless LAN, either one of 2.4 GHz band Bluetooth or wireless LAN (switching based on a control signal from the communication control device) and a 400 MHz band security key system are simultaneously performed. It can be operated.

  Further, as in the antenna device 2B shown in FIG. 6, the 2.4 GHz band radio unit 16 of Bluetooth, the 2.4 GHz band radio unit 17 of the wireless LAN, the secure 400 MHz band radio unit 19, and the DTV 400 MHz radio unit. If each unit 20 is configured to be connected to the duplexer 15 via a switching circuit 18 such as SPDT, either 2.4 GHz band Bluetooth or wireless LAN (switching based on a control signal from a communication control device) One of the 400 MHz band security key system and the digital television broadcasting system (switching based on a control signal from the communication control device) can be operated simultaneously.

(Second Embodiment)
Next, an antenna device 3 according to a second embodiment of the present invention will be described. FIG. 4 is a diagram illustrating an example of the configuration of the antenna device 3. Here, it is assumed that the antenna device 3 corresponds to, for example, the Bluetooth and wireless LAN 2.4 GHz band as the first communication frequency band, and the 400 MHz band communication frequency band of the security key system as the second communication frequency band. However, other frequency bands may be used. In the antenna device 3, the same components as those of the antenna device 2 are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  The antenna device 3 includes a first antenna element 11, a second antenna element 12, a first reactance circuit 13, a second reactance circuit 14, a duplexer (or switching circuit) 15, and Bluetooth 2.4 GHz. The radio unit 16 of the band, the radio unit 17 of the 2.4 GHz band of the wireless LAN, the switching circuit 18, the radio unit 19 of the 400 MHz band, and a duplexer (or switching circuit) 22 are configured. Reference numeral 23 denotes a ground pattern having a ground potential, which is constituted by a conductor pattern on a circuit board, for example.

  The radio unit 17 is a radio unit corresponding to diversity, and one of the two antenna ports is connected to the first antenna element 11 via the switching circuit 18 and the duplexer 15 in the same manner as the antenna device 2.

  Further, in the 400 MHz band, the duplexer 22 connects the one end side of the second antenna element 12 to the one end side of the first reactance circuit 13 different from the grounded side so that energization is possible, and the 2.4 GHz band. 1, one end side of the second antenna element 12 is connected to the other antenna port of the radio unit 17. The duplexer 22 is connected to one end side of the second antenna element 12, one end side of the first reactance circuit 13, and the other antenna port of the radio unit 17.

  The duplexer 22 is set so that the 2.4 GHz band passing loss between the ports to which the second antenna element 12 and the other antenna port of the radio unit 17 are connected is small and the isolation is high in the 400 MHz band. The Further, the 400 MHz band passing loss between the ports to which the second antenna element 12 and the first reactance circuit 13 are connected is small, and isolation is set to be high in the 2.4 GHz band. In addition, the port where the other antenna port of the radio unit 17 and the first reactance circuit 13 are connected is set so that isolation is high.

  Similarly to the first antenna element, the second antenna element 12 is set to an electrical length of about a quarter wavelength in the 2.4 GHz band.

Next, the operation of the antenna device 3 will be described.
In the antenna device 3, the first antenna element 11 operates as a monopole antenna in the 2.4 GHz band of Bluetooth or wireless LAN. Further, since the second antenna element 12 operates as a monopole antenna even in the 2.4 GHz band of the wireless LAN, the second antenna element 12 can have a diversity configuration.

  Further, the antenna device 3 operates as a loop antenna at 400 MHz by the first antenna element 11, the second reactance circuit 14, the second antenna element 12, the ground pattern 23, and the capacitor 13 as a tuning capacitor.

  In the antenna device 3, the duplexer 15 can simultaneously operate either a 2.4 GHz band Bluetooth or a wireless LAN and a 400 MHz band security key system.

  As described above, according to the antenna device 3, the first antenna element and the second antenna element operate as monopole antennas in the first communication frequency band, and the first antenna element in the second communication frequency band. Operates as a loop antenna together with the second antenna element, so that a small antenna device capable of simultaneously operating a plurality of wireless communication applications can be provided. Furthermore, a diversity configuration can be used in the first frequency band.

  In the present embodiment, the case where the first communication frequency band is the 2.4 GHz band and the second communication frequency band is the 400 MHz band has been described, but each communication frequency band is not limited to the above, If the communication frequency band is a frequency band lower than the first communication frequency band, the same effect can be obtained by appropriately setting the frequency characteristic of the second reactance circuit 14.

  Further, as in the antenna device 3B shown in FIG. 7, the 2.4 GHz band radio unit 16 of Bluetooth, the 2.4 GHz band radio unit 17 of the wireless LAN, the secure 400 MHz band radio unit 19 and the 400 MHz radio of the DTV If each unit 20 is configured to be connected to the duplexer 15 via a switching circuit 18 such as SPDT, either 2.4 GHz band Bluetooth or wireless LAN (switching based on a control signal from a communication control device) One of the 400 MHz band security key system and the digital television broadcasting system (switching based on a control signal from the communication control device) can be operated simultaneously.

  Further, an antenna device 3C obtained by modifying the antenna device 3 will be described below with reference to FIG. In the antenna device 3C, the same components as those of the antenna device 3 are denoted by the same reference numerals, and description thereof is omitted or simplified. In the antenna device 3C, the second antenna element 12 is set to an electrical length of about a quarter wavelength in a third communication frequency band that is lower than the first communication frequency band and different from the second communication frequency band. Further, the duplexer 22 has one end of the second antenna element 12 connected to the one end of the first reactance circuit 13 so as to be energized in the second communication frequency band. The power is connected to the wireless unit 17C that transmits or receives power of the wireless communication system in the communication frequency band. Further, the second reactance circuit 14 cuts off the first communication frequency band and the third communication frequency band and allows the second communication frequency band to pass therethrough.

  According to the antenna device 3C, by appropriately setting the frequency characteristics of the second reactance circuit 14 and the duplexer 22, the first antenna element operates as a monopole antenna in the first communication frequency band, and the third communication In the frequency band, the second antenna element operates as a monopole antenna, and in the second communication frequency band, both the first antenna element and the second antenna element operate as loop antennas. A small antenna device capable of simultaneously operating wireless communication applications can be provided.

(Third embodiment)
Next, an antenna device 4 according to a third embodiment of the present invention will be described. FIG. 5 is a diagram illustrating an example of the configuration of the antenna device 4. Here, it is assumed that the antenna device 4 corresponds to, for example, a Bluetooth 2.4 GHz band as a first communication frequency band and a communication frequency band from 470 MHz to 710 MHz for television broadcast reception as a second communication frequency band. However, other communication frequency bands may be used. In the antenna device 4, the same components as those of the antenna device 1 are denoted by the same reference numerals, and description thereof is omitted or simplified.

  The antenna device 4 includes a first antenna element 11, a second antenna element 12, a variable capacitor 21, a second reactance circuit 14, a duplexer (or switching circuit) 15, and a 2.4 GHz band radio unit 16. And 400 MHz band wireless unit 19. Reference numeral 23 denotes a ground pattern having a ground potential, and is constituted by a conductor pattern on a circuit board, for example.

  One end of the variable capacitor 21 is connected to one end of the second antenna element 12, and the other end of the variable capacitor 21 is grounded to the ground pattern 23.

  Next, the operation of the antenna device 4 will be described. Here, the difference in operation with the antenna device 1 will be described.

  The antenna device 4 operates as a loop antenna in the 470 MHz to 710 MHz band by the first antenna element 11, the second reactance circuit 14, the second antenna element 12, the ground pattern 23, and the variable capacitor 21 as a tuning capacitor. . Since this loop antenna can select a tuning capacity suitable for the frequency to be used, in other words, the channel to be used, high antenna performance can be obtained over a wide band.

  Thus, according to the antenna device 4, high antenna performance can be obtained in a small antenna device capable of operating a plurality of wireless communication applications at the same time according to the channel used for a certain wireless communication application.

  The same effect can be obtained by replacing the variable capacitor 21 with a plurality of reactance elements and switching circuits having different values and selecting from a plurality of reactance values according to the frequency (channel) to be used. Thereby, for example, when receiving a digital television broadcast, it becomes possible to change a capacitance according to a channel, and a state with more favorable communication characteristics can be maintained.

  The variable capacitor 21 is not limited to the first reactance circuit 13 of the antenna device 1 but can be applied as the first reactance circuit 13 of the antenna elements 2 and 3.

  In addition, in the case of a straight type portable wireless device, the position where any one of the above antenna devices is mounted in the portable wireless device is near the upper end of the casing or the transmitting portion (microphone) near the receiving unit (speaker). In the case of a lower end portion of a housing and a foldable portable wireless device, in general, the vicinity of the hinge portion is provided in addition to the upper end portion or the lower end portion of the housing.

  The present invention is not limited to the embodiment described above, and can be implemented in various forms without departing from the gist of the present invention.

  INDUSTRIAL APPLICABILITY The present invention is useful as an antenna device, a portable wireless device, and the like that are small in size, can simultaneously operate a plurality of wireless communication applications, and exhibit high antenna performance.

The figure which shows an example of a structure of the antenna apparatus which concerns on the 1st Embodiment of this invention. Explanatory drawing which shows the specific example of the 2nd reactance circuit of the antenna apparatus which concerns on the 1st Embodiment of this invention. The figure which shows an example of a structure of another antenna apparatus which concerns on the 1st Embodiment of this invention. The figure which shows an example of a structure of the antenna device which concerns on the 2nd Embodiment of this invention. The figure which shows an example of a structure of the antenna device which concerns on the 3rd Embodiment of this invention. The figure which shows an example of a structure of another antenna apparatus which concerns on the 1st Embodiment of this invention. The figure which shows an example of a structure of another antenna apparatus which concerns on the 2nd Embodiment of this invention. The figure which shows an example of a structure of another antenna apparatus which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

1, 2, 2B, 3, 3B, 3C, 4 antenna device 11 first antenna element 12 second antenna element 13 first reactance circuit 14 second reactance circuit 15, 22 duplexer 16 first communication frequency Band radio unit 17 Radio unit of first communication frequency band 17C Radio unit of third communication frequency band 18 Switching circuit 19, 20 Radio unit of second communication frequency band 21 Variable capacitor 23 Ground pattern

Claims (5)

An antenna device for communicating signals in a plurality of communication frequency bands including a first communication frequency band and a second communication frequency band,
A first wireless unit that communicates a signal in a first communication frequency band;
A second wireless unit that communicates signals in the second communication frequency band;
A first duplexer connected to be able to energize the first radio unit in the first communication frequency band and connected to be energized to the second radio unit in the second communication frequency band;
A first reactance circuit having one end grounded;
A second reactance circuit that cuts off the first communication frequency band and passes the second communication frequency band;
A first antenna element having one end connected to the duplexer and the other end connected to one end of the second reactance circuit;
A second antenna element having one end connected to the other end of the second reactance circuit and the other end connected to the other end of the first reactance circuit ;
A third wireless unit for communicating signals in the third communication frequency band;
It is connected to the second antenna element, and is connected to one end of the first reactance circuit in the second communication frequency band so as to be energized. In the third communication frequency band, the third communication unit is connected to the third communication unit. A second duplexer connected to be energized;
Have
The second antenna element is connected to the first reactance circuit via the second duplexer,
In the first communication frequency band, the first antenna element operates as a first monopole antenna,
In the second communication frequency band lower than the first communication frequency band, both the first antenna element and the second antenna element operate as a loop antenna,
An antenna device in which the second antenna element operates as a second monopole antenna in the third communication frequency band that is lower than the first communication frequency band and different from the second communication frequency band . The antenna device according to claim 1 ,
An antenna device in which the third communication frequency band is equal to the first communication frequency band. The antenna device according to claim 1 or 2 ,
The first reactance circuit is an antenna device having a variable capacitor. The antenna device according to any one of claims 1 to 3 ,
The first reactance circuit is an antenna device that includes a plurality of reactance elements, and is selected from the plurality of reactance elements according to a frequency used in the plurality of communication frequency bands. Portable wireless device comprising the antenna device according to any one of claims 1 to 4.

Images