JP2008294635A - Antenna unit and portable radio apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small double power feeding antenna to be operated by two frequencies. <P>SOLUTION: Power is supplied from a first radio part 14 to one end of a radiation conductor 12, and from a second radio part 15 to the opposite end. The first radio part 14 includes: a first transmitting circuit; a first receiving circuit; a first demultiplexer; and a first matching circuit. The second radio part 15 includes: a second transmitting circuit; a second receiving circuit; a second demultiplexer; and a second matching circuit. The radiation conductor 12 is operated as a deformed folded monopole antenna with respect to the first radio part 14 and operated as a reverse L-shaped antenna with respect to the second radio part 15. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an antenna device and a portable radio (communication terminal) using the antenna device.

  In recent years, with the spread of mobile phones, their multi-functionality has been advanced, and wireless functions other than mobile phones such as multi-band frequencies used in mobile phones and Bluetooth, wireless LAN, and 1Seg have come to be installed. It is coming. Accordingly, the number of necessary antennas can be increased, and a large space is required to form the antennas. On the other hand, there is a great demand from users for further miniaturization and thinning of the mobile phone itself. In that case, it is necessary to reduce the size without degrading the performance of the antenna. The following documents are related to the multi-frequency shared microstrip antenna.

JP 05-175722 A

As an antenna system for a mobile phone that supports multiband in general use, for example, as an antenna for a mobile phone that supports two frequencies,
1) A two-resonant inverted L antenna that has one feeding point, the antenna branches in the middle, and is divided into elements corresponding to the respective frequencies,
2) There is one antenna, and a two-resonant inverted-F antenna that uses the resonance of the multiplied wave is often used.

  On the other hand, in recent years, the structures of mobile phones themselves have been diversified, and it has been confirmed that the position of the feeding point greatly affects the superiority or inferiority of the antenna characteristics depending on the frequency used. In the antenna system, since there is a single feeding point, it is difficult to set the optimum feeding point position for each frequency, which is a cause of an obstacle to miniaturization of the antenna.

  A method of providing a feeding point and an antenna for each frequency is also used. However, in this case, it is disadvantageous for miniaturization in that it is necessary to prepare two antennas, and it is necessary to secure a distance between the antennas in order to avoid coupling between the two antennas. Therefore, downsizing becomes more difficult. An object of the present invention is to reduce the size of an antenna.

  The present invention overcomes the above problem by feeding one antenna from two feeding points.

  There are radiation conductors that are fed to different ends from a first radio unit that uses the first frequency and a second radio unit that uses a second frequency different from the first frequency. The impedance of the second radio section is designed to be low impedance at the first frequency and 50Ω at the second frequency, and the impedance of the first radio section viewed from the radiation conductor is set to 50Ω at the first frequency, and the second frequency. In, it is designed to high impedance. At this time, by designing the electrical length of the radiating conductor to be ½ wavelength of the first frequency and ¼ wavelength of the second frequency, the radiating conductor is deformed 1 in the first radio unit. It operates as a 1/2 wavelength folded monopole antenna, and the second radio unit operates as a 1/4 wavelength inverted L antenna.

  In the clamshell type in which the first housing and the second housing are connected to each other by a hinge portion or a folding mobile phone having a biaxial rotating hinge, the first housing or the second antenna is used. The above-mentioned antenna is arranged on the hinge part side of the casing, and two feeding parts are arranged at both ends of the upper end part of the first circuit board, respectively, and the upper and lower casing connecting means and the first circuit board By disposing the contact point on the side of the power feeding unit with the higher frequency, the antenna characteristics at each frequency when the cellular phone is opened can be improved.

  When there is an antenna at the hinge portion of the mobile phone that can be opened and closed, when the mobile phone is opened, the housing on which the antenna is not mounted approaches the antenna, so that the antenna characteristics are affected. When the frequency of the antenna to be used is relatively low such as the 800 MHz band, the contact point with the upper and lower board connecting means at the upper end of the first circuit board is opposite to the antenna feeding point at the upper end of the first circuit board. By disposing it on one end side, it is possible to improve the antenna characteristics when the mobile phone is opened. This is because the second circuit board as viewed from the antenna feeding point is connected with a certain electrical length at a high frequency, and the second circuit board including the upper and lower casing connecting means and the second circuit board is included. This is because the electrical length of the second casing can be set to about ¼ wavelength of the frequency, and as a result, the second casing can be excited.

  If the antenna is disposed at one end on the same side as the feeding point of the antenna, the antenna characteristics are deteriorated. This is because when the second casing is connected to the feeding point of the antenna with a short electrical length, the second casing operates as a part of the ground conductor, that is, almost to the antenna as a GND. When the antenna opens, the characteristics deteriorate due to the antenna and GND approaching each other.

  In addition, when the frequency used is relatively high, such as the 2 GHz band, the wavelength is about half that of the 800 MHz band. Therefore, when the upper and lower substrate connecting means are arranged on the side opposite to the antenna feeding point, Since the electrical length of the second casing including the board connecting means and the second circuit board is about ½ wavelength, the effect of improving the antenna characteristics can hardly be expected.

  On the contrary, when the connecting means of the upper and lower casings are arranged on the same side as the power feeding part of the antenna, the electrical length can be brought close to about ¼ wavelength, so that the antenna characteristics are improved from the same effect as described above. be able to. As described above, the antenna characteristics when the cellular phone is opened are made favorable by optimally arranging the power feeding units corresponding to the respective frequencies.

  According to the present invention, both ends of the radiation conductor can be operated as antennas at two different frequencies by using different frequencies and being fed from two radio units, respectively. Therefore, since two frequencies can resonate with one radiation conductor, the volume required by the antenna can be greatly reduced.

  In addition, when there is an antenna in the hinge part of the mobile phone that can be opened and closed, when the mobile phone is opened, the influence of the antenna characteristics due to the case on which the antenna is not mounted approaching the antenna is reduced. be able to. The antenna characteristics when the cellular phone is opened can be improved by optimally arranging the power feeding units corresponding to the respective frequencies.

  Hereinafter, a mobile terminal according to an embodiment of the present invention will be described with a mobile phone as an example with reference to the drawings. 1A and 1B are diagrams showing a schematic configuration example of a mobile phone according to the first embodiment of the present invention. 1A (a) is a perspective view of a mobile phone, and FIG. 1A (b) is a diagram showing a positional relationship between an antenna provided in the mobile phone and a circuit board, and FIG. 1A (c) These are the figures which showed the relationship with the radio | wireless part of an antenna. FIGS. 1B (a) and 1 (b) are diagrams showing examples of impedance characteristics of the first radio unit and the second radio unit, and FIG. 1C (a) shows the first radio unit and the second radio unit. FIG. 1C (b) is a diagram showing an example of the matching circuit in FIG. 1C (a).

  As shown in FIG. 1A, the antenna according to the present embodiment is arranged at the upper end of the casing 11 of a straight type mobile phone, and one end of the radiating conductor 12 extends from the first radio unit 14 to the first feeding unit. The other end is fed from the second radio unit 15 to the second feeding unit. The first power supply unit and the second power supply unit are provided between the first radio unit 14 and the radiation conductor 12 and between the second radio unit 15 and the radiation conductor 12.

  The first radio unit 14 uses the first frequency band f11, the second radio unit 15 uses the second frequency band f12, and the first frequency band f11 and the second frequency band f12 are different. The frequency band. As in the impedance characteristic of the Smith chart shown in FIG. 1B (a), the impedance of the first radio unit 14 viewed from the radiation conductor 12 is designed to be approximately 50Ω in the first frequency band f11, and the second frequency In the band f12, the impedance is high and it is a substantially open end. On the other hand, the impedance of the second radio unit 15 as viewed from the radiation conductor 12 is low in the first frequency band f11 and substantially short-circuited, and is designed to be approximately 50Ω in the second frequency band f12. . For this reason, since the first radio unit 14 and the radiation conductor 12 are not matched at the second frequency f12, radio waves transmitted from the second radio unit 15 are directly transmitted through the radiation conductor 12 to the first frequency. Is not incident on the wireless unit 14. Even at the first frequency f11, for the same reason, the radio wave transmitted from the first radio unit 14 does not directly enter the second radio unit 15 through the radiation conductor 12. Accordingly, since the two radio units 14 and 15 do not break each radio unit when a strong input radio wave transmitted from the other radio unit is incident, use the two radio units simultaneously. There is an advantage that can be.

  As an example of a method for adjusting the impedance of each of the radio units 14 and 15, as shown in FIG. 1C (a), the first radio unit 14 includes a first transmission circuit 16, a first reception circuit 17, 1 includes a first duplexer 18 and a first matching circuit 19. Similarly to the first radio unit 14, the second radio unit 15 includes a second transmission circuit 110 and a second reception circuit 19. 111, a second duplexer 112, and a second matching circuit 113.

  By adjusting the matching circuits 19 and 113, the impedances of the radio units 14 and 15 viewed from the radiation conductor 12 are adjusted. As shown in FIG. 1C (c), each of the matching circuits 19 and 113 includes a coil L and a capacitor C. Instead of these, other components having inductivity and capacitance are used. Also good.

  According to the above configuration, the radiation conductor 12 operates as a modified folded monopole antenna with respect to the first radio unit 14 because the tip of the radiating conductor 12 is equivalent to the short-circuited end. On the other hand, for the second radio unit 15 in the second frequency band f12, the radiating conductor 12 operates as an inverted L antenna because the tip is equivalent to the open end. At this time, the electrical length of the radiation conductor 12 in the first frequency band f11 viewed from the first radio unit 14 is 1 / 2λ, and the radiation conductor in the second frequency f12 viewed from the second radio unit 15 By adjusting the size of the radiating conductor 12 so that the electrical length of 12 becomes ¼λ, the radiating conductor 12 becomes a ½λ deformed folded monopole in the first radio unit 14 at the first frequency f12. Since it operates as an antenna, the impedance of the antenna can be increased, and a good antenna can be obtained in a wide band. On the other hand, at the second frequency f12, the second radio unit 15 operates as a 1 / 4λ inverted L antenna.

  As described above, by adjusting the electrical length of the radiating conductor 1 to be about ½ of the wavelength in the first frequency band f11 and about ¼ of the wavelength in the second frequency band f12, 1 Two antennas can be used for the two radio units 14 and 15.

  For this reason, conventionally, an antenna is required depending on the system to be used. However, in the present embodiment, since one antenna can be shared by two systems, the antenna characteristics remain good. Space required for the antenna can be reduced. In addition, as the antenna for the first radio unit 14, by using the 1 / 2λ system modified folded monopole method, the antenna area is used larger than when the 1 / 4λ inverted L antenna method is used. Therefore, the antenna characteristics can be improved by the amount of the antenna area.

  Further, according to this relationship, the first frequency band f11 needs to be about twice the second frequency band f12. However, the frequency adjustment is possible by providing a matching circuit in each power feeding unit. .

  To give a more specific example, for example, when a WCDMA system using the 2 GHz band used in Japan is a first radio unit and a PDC system using an 800 MHz band is a second radio unit, PDC Since the (800 MHz band) has a wavelength nearly twice that of WCDMA (2 GHz band), the configuration according to this embodiment can be used as it is.

  In the conventional method, it is necessary to prepare an antenna for PDC and an antenna for WCDMA, and the space required for the antenna increases accordingly, but by using the configuration in this embodiment, Two system antennas can be configured in a smaller space. Further, according to the present embodiment, the respective feeding portions are provided at both ends of the radiating conductor. By doing so, the antenna volume can be used to the maximum, and the antenna characteristics are further improved. Can be.

  1A and 1B are diagrams showing an arrangement example of the ground pattern (ground conductor) and the circuit board 13. FIG. 1D (a) is a diagram showing a configuration on the back side of the liquid crystal display surface with respect to the liquid crystal display surface of the mobile phone, and an area where the antenna 12 is provided on one end side of the circuit board 13 and this antenna 12 is not provided. In addition, a ground pattern 16a is provided. As shown in FIG. 1D (b), when viewed from the liquid crystal side, the antenna 12 is provided on the back surface side, and a ground pattern 16b is provided in a region of the circuit board 13 avoiding the antenna 12. Around the ground pattern 16b, contacts 20 with a plurality of liquid crystal holders are provided. The ground pattern is a ground potential pattern at an arbitrary place other than the position where the antenna is arranged on the circuit board 13 and is integrated with the circuit board.

  2A (a) to 2B (b) are diagrams illustrating a configuration example of an antenna device according to the second embodiment of the present invention. FIG. 2A (a) is a front view of a foldable mobile phone incorporating an antenna device, FIG. 2A (b) is a diagram showing an arrangement example of the antenna device in the mobile phone, and FIG. FIGS. 2C and 2B are diagrams showing the relationship between the device and the radio unit, and FIGS. 2C and 2B show the radiation conductor and the second housing (with the antenna arranged) when the mobile phone is opened and closed. It is a figure which shows the positional relationship with the housing | casing which is not.

  As shown in these drawings, the mobile phone according to the present embodiment includes a first casing 21, a display unit 26, and a second circuit that incorporate a radiation conductor 23, a first circuit board 24, a key unit 25, and the like. The second casing 22 containing the substrate 27 and the like is connected to the upper end portion of the first casing 21 and the lower end portion of the second casing 22 by a hinge portion 28. One end of the upper end portion of the first circuit board 24 and one end of the lower end portion of the second circuit board 27 on the second housing 22 side are connected by a thin coaxial 29 that passes through the inside of the hinge portion 28. .

  One end (the left side in the figure) of the radiation conductor 23 is from one end closer to the connection position of the thin coaxial 29 at the upper end portion of the first circuit board 24 by the first radio unit 212 via the first signal selection unit 210. Power is being supplied. One end on the opposite side of the radiation conductor 23 is fed from the second radio unit 213 via the second signal selection unit 211 from one end far from the connection position of the thin coaxial line 29 at the upper end of the first circuit board 24. Has been.

  The first radio unit 212 uses the first frequency band f21, and the second radio unit 213 uses the second frequency band f22. F21 and f22 are different frequency bands. The first signal selection unit 210 connects the first radio unit 212 and the radiation conductor 23 at approximately 0Ω at the first frequency, and the second signal viewed from the radiation conductor 23 at the second frequency. The impedance of the wireless unit 213 is set to a high impedance that is almost electrically close to the open end.

  On the other hand, the second signal selection unit 211 makes the impedance of the second radio unit 213 viewed from the radiating conductor 23 as low as electrically close to the short-circuited end at the first frequency, At the second frequency, the radiation conductor 23 and the second radio unit 213 are connected at approximately 0Ω.

  The above configuration uses the first signal selection unit 210 and the second signal selection unit 211 instead of what is shown as an open end or a short circuit end due to the impedance on the circuit side in the first embodiment. Thus, the same effect can be obtained. That is, with respect to the first radio unit 212, the second signal selection unit 211 is equivalent to being connected to GND at the first frequency f21 to be used, so that the tip of the radiation conductor is short-circuited. And operates as a 1 / 2λ folded monopole antenna.

  Further, at the second frequency f22, the tip of the radiation conductor 23 viewed from the second radio unit 213 is an open end, and the radiation conductor operates as a 1 / 4λ monopole antenna.

  One configuration example of the first signal selection unit and the second signal selection unit is shown in FIG. 2D. As shown in FIG. 2D, the first signal selection unit and the second signal selection unit can be configured by a filter or the like.

  The radiation conductor 23 is connected to the radio unit 212 via the first filter 214 at one end and is connected to the second radio unit 213 at the other end, but in the middle, the second filter 215 is connected. It is connected to GND via The first filter 214 connects the first radio unit 212 and the radiation conductor 23 with almost no loss at the first frequency, and exhibits a very high impedance at the second frequency. 23 shows such a characteristic that current does not flow from 23 to the first wireless unit 212.

  The second filter 215 connects the radiation conductor 23 and GND at the first frequency, exhibits a very high impedance at the second frequency, and prevents current from flowing from the radiation conductor 23 to GND. Show the characteristics. Since the first filter 214 and the second filter 215 have the same required frequency characteristics, the same filter may also be used.

  As described above, these filters can satisfy the characteristics required for each signal selection means. Moreover, according to this Embodiment, there exist the following further effects by having arrange | positioned the antenna to the hinge part of a foldable mobile telephone. That is, when there is an antenna at the hinge part of a mobile phone that can be opened and closed generally, when the mobile phone is opened, the housing on which the antenna is not mounted approaches the antenna. Influence. For example, when the frequency of the antenna to be used is relatively low, such as 800 MHz band, the first circuit board composed of a thin coaxial line or FPC at the upper end of the first circuit board is connected to the second circuit board. The contact point with the upper and lower board connecting means for performing the antenna characteristic when the mobile phone is opened is arranged on one end side opposite to the antenna feeding point arranged on the upper end portion of the first circuit board. Can be good.

  This is because the second circuit board viewed from the antenna feeding point is connected with a certain electrical length in terms of high frequency, and the second circuit board including the upper and lower housing connecting means and the second circuit board is included. This is because the electrical length of the second casing can be about ¼ wavelength of the frequency, and as a result, the second casing can be excited.

  If the antenna is disposed at one end on the same side as the feeding point of the antenna, the antenna characteristics are deteriorated. This is because when the second housing is connected with a short electrical length to the feeding point of the antenna, the second housing operates as a part of the ground conductor, that is, almost GND as to the antenna. This is because, when the mobile phone is opened, the characteristics are deteriorated due to the proximity of the antenna and GND.

  Further, when the frequency used is a relatively high frequency band such as the 2 GHz band, the wavelength is about half that of the 800 MHz band. Therefore, when the upper and lower substrate connecting means are arranged on the side opposite to the antenna feeding point, the antenna Since the electrical length of the second casing including the upper and lower substrate connecting means and the second circuit board is about ½ wavelength as viewed from the feeding point, the effect of improving the antenna characteristics can hardly be expected. .

  On the contrary, when the connection means of the upper and lower casings is arranged on the same side as the power feeding part of the antenna, the electrical length can be brought close to about ¼ wavelength, so that the antenna characteristics are improved from the same effect as described above. can do.

  That is, when the 800 MHz band is used like a PDC, if there is an antenna feeding point at one end of the upper end of the first circuit board 24, the antenna feeding point is opposite to the antenna feeding point at the upper end of the first circuit board 24. It is advantageous for the antenna that one end of the antenna is connected to the second circuit board via a thin coaxial line or FPC to excite the second casing when the mobile phone is opened, and to increase the gain and the bandwidth. On the other hand, when the 2 GHz band is used, the second casing is excited when the mobile phone is opened when the second circuit board is connected from the same end as the antenna, which is advantageous for the antenna. It is.

  In this embodiment, when the first radio unit is a WCDMA (2 GHz band) radio unit and the second radio unit is a PDC (800 MHz band), the effect in the state in which the cellular phone is folded is the same. , The feeding point of the WCDMA antenna is close to the connection position between the thin wire coaxial 29 and the first circuit board 24, and conversely, the PDC antenna feeding point is from the connection position between the thin wire coaxial 29 and the first circuit board 24. Since it is far away, the second housing can be excited at any frequency when the mobile phone is opened, and a high-gain and wide-band antenna can be realized.

  As described above, according to the antenna device according to the present embodiment, the antenna characteristics can be made better than those of the conventional antenna, so that there is an advantage that the antenna apparatus can be downsized without degrading the characteristics.

  An antenna device according to a third embodiment of the present invention will be described with reference to FIGS. 3A to 3D. 3A is a front view of a foldable mobile phone incorporating the antenna device according to the present embodiment, FIG. 3B is a diagram clearly showing the position of the antenna device in the mobile phone, and FIG. 3C is an antenna device. FIG. 3D is a flowchart showing the switching procedure of each switching unit.

  The basic configuration of a mobile phone incorporating the antenna device according to the present embodiment is almost the same as that of the mobile phone according to the second embodiment, but as shown in FIGS. The first circuit board 34 and the second circuit board 37 are arranged inside the second casing 32 and in the vicinity of the hinge part 38, and the first circuit board 34 and the second circuit board 37 are arranged on the hinge part 38 side by a thin line coaxial 39, respectively. Connected to one end. In addition, the arrangement of the first circuit board 24, the second circuit board 37, and the display unit 36 is the same as that of the mobile phone according to the second embodiment.

  One end of the radiation conductor 33 is supplied with power from the first radio unit 312 and the other end is supplied with power from the second radio unit 313. A first switching unit 310 is provided between the radiation conductor 33 and the first radio unit 312, and a second switching unit 311 is provided between the radiation conductor 33 and the first radio unit 313. Yes.

  The first switching unit 310 and the second switching unit 311 are controlled by the control signal from the control unit 314 as follows, as shown in FIGS. 3D (a) and (b). The process is started (step S1: start). When the first radio unit 312 is used in step S2 (step S2), the process proceeds to step S4, and the first switching unit 310 is switched to the first radio unit 312. And the radiation conductor 33 are connected (state 2 in FIG. 3D (b)), and the second switching unit 311 disconnects the second radio unit 313 and the radiation conductor 33 to form the radiation conductor 33 and the ground conductor. 2 is connected to GND of the circuit board 2 (state 2 in FIG. 3D (b)). When the second radio unit 313 is used (step S2), the process proceeds to step S3, where the first switching unit 310 disconnects the connection between the first radio unit 312 and the radiation conductor 33, and the second switching unit 311. Cuts the connection between the radiation 33 and the GND of the second circuit board, and connects the radiation conductor 33 and the second radio unit 313 (state 1 in FIG. 3D (b)).

  With the above configuration, the radiating conductor 33 operates as a short-circuited modified folded monopole antenna for the first radio unit 312, and for the second radio unit 313, as in the second embodiment. Operates as an inverted L antenna with an open tip. In addition, since the radiation conductor is built in the second housing 32, the present embodiment has an advantage that the antenna is not easily handled during a call and the deterioration amount of the antenna characteristic is small.

  4A to 4D are diagrams showing a mobile phone provided with an antenna device according to a fourth embodiment of the present invention. 4A is a front view of a foldable mobile phone incorporating the antenna device, FIG. 4B is a diagram showing the position of the antenna device in the mobile phone, and FIG. 4C shows the relationship between the antenna device and the radio unit. FIG. 4D is a diagram illustrating a configuration example of the switching device, and FIG. 4E is a flowchart illustrating an example of a control method of the switching device.

  The difference between the fourth embodiment and the second embodiment is that the presence / absence of the switching device 414 and the first circuit board 44 and the second circuit board 47 are connected by the FPC 49 instead of the thin line coaxial. The difference is that an opening / closing detection means 419 and a magnet 420 are added. 4D, the switching device 414 includes a switch 416, a coil 417, a capacitor 418, a circuit pattern (wiring), and the like, and the second filter is controlled by a control signal from the control unit 415. The connection condition between 411 and GND of the first circuit board can be switched to three states, state 1, state 2, and state 3. Each state is determined as follows. The switching device 414 connects the second filter 411 and the first circuit board GND as they are in the state 1, and connects the second filter 411 and the GND of the first circuit board via the coil 417 in the state 2. In the state 3, the second filter 411 and the GND of the first circuit board are connected via the capacitor 418.

  Of course, the above configuration has the advantages described in the second embodiment, but in the present embodiment, by providing the switching device 414, the advantages described below are added. . That is, when the switching device 414 is in the state 1, the radiating conductor 43 viewed from the first radio unit 412 operates as a modified ½λ folded monopole as in the technique according to the second embodiment. In the case of the state 2, since it is connected to the GND via the coil 417, the resonance frequency of the antenna is shifted in a direction lower than that in the state 1. In the case of the state 3, since it is connected to the GND via the capacitor 418, the resonance frequency of the antenna is shifted in a direction higher than that in the state 1.

  As shown in FIG. 4E, the process is started in step S11. In step S12, it is determined whether the first radio unit 412 or the second radio unit 413 is used, and the first radio unit 412 is used. If used, the process is terminated (step S19). The second wireless unit 413 is used to determine whether or not the mobile phone is closed in step S14. If the mobile phone is closed, the process proceeds to step S15 and the switching device 414 is set to state 1. If it is open, the process proceeds to step S16 to determine whether or not a call is in progress. If the call is not in progress, the switching device 414 is set in the state 2 in step S17. If the call is in progress, the process proceeds to step S18, the switching device 414 is set in the state 3, and the process is terminated (step S19: end).

  An advantage of this configuration is that the resonance frequency of the antenna can be corrected by controlling the switching device 414 when the resonance frequency of the antenna is shifted. For example, in the case where an antenna is arranged at the hinge portion of a foldable mobile phone, the resonance frequency of the antenna often shifts to a lower side when the mobile phone is opened from the closed state. This is because the case on the front side approaches the antenna when the mobile phone is opened. However, when the technique according to this embodiment is used, for example, the open / close detection means 419 and the magnet 420 are close to each other. Therefore, it is determined that the mobile phone is closed and the mobile phone is open because the magnet 420 is separated. Based on this information, the control unit 415 determines whether the mobile phone is When in the closed state, the switching device 414 is in state 2, and when it is in the open state, the switching device 414 is in state 1.

  In a cellular phone antenna, it is known that the resonance frequency shifts to a lower side due to the influence of a person's head or hand during a call. However, by changing the state of the switching unit to state 3 during a call, the resonance frequency of the antenna The deviation can be corrected.

  FIGS. 5A to 5C are diagrams showing a mobile phone including an antenna device according to a fifth embodiment of the present invention. FIG. 5A is a front view of a foldable mobile phone incorporating the antenna device, FIG. 5B is a diagram showing the position of the antenna device in the mobile phone, and FIG. 5C shows the relationship between the antenna device and the radio unit. FIG. 5D is a flowchart showing the operation of the switching unit.

  Unlike the second embodiment, this embodiment supplies power to one radiating conductor for each frequency band with respect to a multi-band radio unit. One end of the radiation conductor 53 disposed in the vicinity of the hinge portion 58 inside the first housing 51 is supplied with power by the first power supply portion 515 and is supplied with power by the second power supply portion 516 from the opposite end. The first power supply unit 515 and the second power supply unit 516 are connected to a switching unit 512 configured by a switch or the like, and the switching unit 512 is connected to a radio unit 513 corresponding to a tri-band.

  Switching unit 512 switches between two states in accordance with a control signal from control unit 514 as follows. When these two states are defined as state 1 and state 2, in state 1, radio unit 513 and the first power supply The unit 515 is connected, and in the state 2, the wireless unit 513 and the second power feeding unit 516 are controlled to be connected.

  In addition, a first filter 510 is disposed between the first power feeding unit 515 and the switching unit 512, and the radiating conductor 53 is connected between the second power feeding unit 516 and the switching unit 512. Are connected to the GND of the first circuit board through the filter 511. The first filter 510 and the second filter 511 are the same filter, and the first frequency f51 used in the radio unit 513 has an impedance of 100Ω or more, and the second frequency band f52 and the third frequency. At f53, the impedance is low and is approximately 0Ω.

  As a specific example, the wireless unit 513 is a GSM wireless unit that is a mobile phone system overseas, the first frequency f51 is the GSM900 band, the second frequency f52 is the DSC1800 band, and the third frequency f53 is The PCS1900 band is assumed. The switching unit 512 is controlled by the control unit 514. The control procedure will be described with reference to the flowchart of FIG. 5D. As shown in FIG. 5D, the process is started (step S21: start). In step S22, it is determined whether to use radio waves in the GSM900 band, the DCS1800 band, or the PCS1900 band.

  Here, when communication is performed using radio waves of the GSM900 band, the process proceeds to step S23, where the control unit 514 sends a control signal to the switching unit 512 so as to be in the state 2, and the switching unit 512 is connected to the wireless unit 513 and the second unit. The power feeding unit 516 is connected. The radiation conductor 53 is substantially equivalent to the open end of the first filter 510, and the electrical length of the radiation conductor 53 as viewed from the second power feeding portion is designed to be approximately 1 / 4λ. Operates as a 4λ inverted L antenna.

  On the other hand, when using the DCS1800 band or the PCS1900 band radio wave, the process proceeds to step S24, where the control unit 514 sends a control signal to the switching unit 512 so as to set the state 1, and the switching unit 512 is connected to the wireless unit 513 and the first unit. A power feeding unit 515 is connected. In the frequency bands of DCS 1800 and PCS 1900, the tip of the radiation conductor 53 viewed from the first power feeding unit 515 is equivalent to one that is short-circuited by the GND of the first circuit board. Since the DSC1800 band and the PCS1900 band are about twice the frequency of the GSM900 band, the electrical length of the radiation conductor is about 1 / 2λ in the DSC1800 band and the PCS1900 band, and operates as a modified 1 / 2λ folded monopole antenna. . And operation | movement is complete | finished (step S25). A description of states 1 and 2 is shown in FIG. 5C (b).

  According to the above configuration, it is possible to prepare a conventional radiation conductor for GSM900 and a radiation conductor for DCS1800 band and / PCS1900 band, respectively, and to reduce the size of the antenna as compared with the case where the antenna is formed. The antenna characteristics of DCS1800 and PCS1900 can be set to a high impedance by using a modified folded monopole antenna. Therefore, compared with a conventional inverted L antenna, the antenna has a wide band and a high gain. Can be. Furthermore, as with the technique according to the second embodiment, since each feeding point can be arranged so as to be advantageous to the antenna of each frequency band, the antenna can be further miniaturized. Further, by providing a matching circuit for each feeding point, the impedance of each antenna can be improved.

  6A to 6D are diagrams illustrating an antenna device according to a sixth embodiment of the present invention. 6A is a front view of a foldable mobile phone incorporating the antenna device, FIG. 6B is a diagram showing the position of the antenna device in the mobile phone, and FIG. 6C shows the relationship between the antenna device and the radio unit. FIG. FIG. 6D is a diagram illustrating a configuration example of the switching device. These configurations are substantially the same as those of the fifth embodiment, except that a switching device 615 is provided between the second filter 611 and the GND of the first circuit board.

  As shown in FIG. 6D, the switching device 615 includes a switch 620, a coil 618, a capacitor 619, a circuit pattern, and the like. The control method is the same as that in the third embodiment. The connection condition between the second filter 611 and the GND of the first circuit board is changed by the control signal. The switching device 615 connects the second filter 611 and the first circuit board GND as they are in the state 1, and connects the second filter 611 and the GND of the first circuit board via the coil 618 in the state 2. In the state 3, the second filter 611 and the GND of the first circuit board are connected via the capacitor 619.

  Of course, the above configuration provides the effects of the fifth embodiment, but the provision of the switching device 615 adds the following effects. When the switching device 615 is in the state 1, the radiating conductor 63 viewed from the wireless unit 613 operates as a modified ½λ folded monopole as in the fifth embodiment. In the case of the state 2, since it is connected to the GND via the coil 618, the resonance frequency of the antenna is shifted in a direction lower than that in the state 1. In the case of the state 3, since it is connected to the GND via the capacitor 619, the resonance frequency of the antenna is shifted in a direction higher than that in the state 1.

  The merit of this configuration is the same as that described in the fourth embodiment. Apart from that, the resonance frequency of the antenna can be tuned by the switching device 615. A specific example will be described. For example, the radio unit 613 is a GSM900 / DSC1800 / PCS1900 / WCDMA quad-band radio unit, and the first frequency band f61 is the GSM900 band and the second frequency band. Let f62 be the DCS1800 band, the third frequency band f63, and the fourth frequency band f64 be the WCDMA band. The electrical length of the radiation conductor 63 is designed to be about 1 / 4λ of the GSM900 band and 1 / 2λ of the PCS1900 band. When the GSM900 band is used, the switching unit 612 disconnects the connection between the wireless unit 613 and the first filter 610 and connects the wireless unit 613 and the second power feeding unit 617, that is, the radiation conductor 63 is the second one. The power supply unit 617 supplies power and operates as a 1 / 4λ inverted L antenna.

  On the other hand, when using the DCS 1800 band, the PCS 1900 band, and the WCDMA band, the switching unit 612 disconnects the connection between the wireless unit 613 and the second power feeding unit 617 and connects the wireless unit 613 and the first filter 610. Connecting. That is, the radiating conductor 63 is fed from the first feeding unit 616 and operates as a 1 / 2λ deformed folded monopole antenna, but the resonance frequency can be adjusted by the connection state of the switching device 615.

  As described in the fourth embodiment, when the switch 620 is connected to the GND of the first circuit board via the coil 618, the resonance frequency is the lowest, and the second is nothing without the next. When the switch is connected to the GND of the first circuit board 64, the resonance frequency is highest when the switch is connected to the GND of the first circuit board 64 via the capacitor 619. For each band, the DSC 1800 band has the lowest frequency, followed by the PCS 1900 band and the WCDMA band. By using the switching device 615 to tune the resonance frequency of the antenna for each frequency band to be used, a higher gain antenna can be obtained.

  7A to 7D are diagrams showing an antenna device according to a seventh embodiment of the present invention. 7A is a perspective view of a mobile phone incorporating the antenna device, FIG. 7B is a diagram showing the positional relationship between the antenna device inside the mobile phone and the circuit board, and FIG. 7C is the shape of the radiation conductor in FIG. 7B. Is a meander shape. The configuration of the mobile phone is exactly the same as that of the first embodiment, except that the frequency is adjusted by making a cut in the radiation conductor 72. Further, the resonance frequency of the antenna can be lowered by making the antenna meander as shown in FIG. 7D.

  As described above, according to the antenna device according to the present embodiment, both ends of the radiating conductor are operated as antennas at two different frequencies by being fed from two radio units using different frequencies, respectively. be able to. Therefore, since two frequencies can resonate with one radiation conductor, the volume required by the antenna can be greatly reduced.

  Also, if the antenna is provided in the hinge part of the mobile phone that can be opened and closed, when the mobile phone is opened, the housing without the antenna is closer to the antenna, so the antenna characteristics are also affected. receive. When the frequency of the antenna to be used is relatively low, such as the 800 MHz band, the contact point with the upper and lower substrate connecting means provided at the upper end of the first circuit board is the antenna feed point at the upper end of the first circuit board. By disposing at one end side on the opposite side, the antenna characteristics when the cellular phone is opened can be improved. This means that the second circuit board viewed from the antenna feeding point is connected with a certain electrical length at a high frequency, and the second circuit board including the upper and lower housing connecting means and the second circuit board is included. This is because the electrical length of the second casing can be set to about ¼ wavelength of the frequency, and as a result, the second casing can be excited.

  If the antenna is disposed at one end on the same side as the feeding point of the antenna, the antenna characteristics are deteriorated. This is because the second housing is connected to the feeding point of the antenna with a short electrical length, so that the second housing operates as a part of the ground conductor, that is, almost as a GND with respect to the antenna. When the telephone is opened, the characteristics deteriorate due to the close proximity of the antenna and GND.

  In addition, when the frequency used is relatively high, such as the 2 GHz band, the wavelength is about half that of the 800 MHz band. Therefore, when the upper and lower substrate connecting means are arranged on the side opposite to the antenna feeding point, Since the electrical length of the second casing including the board connecting means and the second circuit board is about ½ wavelength, the effect of improving the antenna characteristics can hardly be expected. On the contrary, when the connecting means of the upper and lower casings are arranged on the same side as the power feeding part of the antenna, the electrical length can be brought close to about ¼ wavelength, so that the antenna characteristics are improved from the same effect as described above. be able to. As described above, the antenna characteristics when the cellular phone is opened can be improved by optimally arranging the power feeding units corresponding to the respective frequencies.

  8A to 8E are diagrams showing an antenna device according to an eighth embodiment of the present invention. In FIG. 8A, the first power supply unit 83 in the first embodiment is left as it is, and the second power supply unit 84 is circuitd from the end of the circuit board 81 by ¼ of the length L in the width direction of the circuit board 81. It is a figure which shows the structure moved to the inner side of the board | substrate.

  In general, most antennas used in mobile phones are operated as antennas by passing a current to the housing side. In many cases, the feeding point of many antennas is designed to be provided at the end of the ground conductor. The main purpose of this is to make effective use of the casing current, to keep the antenna as far away from GND as possible, and to make maximum use of the volume given to the antenna in the mobile phone.

  When the feeding point of the antenna is inside rather than the end, the housing current flows toward both ends as shown in FIG. 8B. If these are the case current A and the case current B, respectively, the two currents cancel each other because the directions are opposite. Therefore, simply considering, the casing current is the difference between the casing current A and the casing current B, and the casing current cannot be used to the maximum. That is, in a general-sized mobile phone, when there is an antenna at the hinge part, it is advantageous that the feeding point is as far as possible to effectively use the housing current. If the length is up to about / 4, even if the feeding point is inside, the characteristics are not deteriorated so much.

  On the other hand, when the antenna is at the end, it is often known that the antenna characteristics will be deteriorated because the hand or finger is often applied to the antenna during a call or the like, and the feeding point is designed inside. The effect can be reduced.

  From the above two points, the feeding point of the antenna is set to a distance shorter than about 1/4 of the length in the width direction from the end of the ground conductor, and depending on whether the standby characteristic or the call characteristic is emphasized, By determining the feeding point within the range, the antenna characteristics can be improved with good balance.

  Further, as the antenna shape, FIG. 8C (a configuration in which the first and second feeding points 83 and 84 are arranged at substantially both ends of the radiation conductor 82), and FIG. 8D (the first and second feeding points 83 and 84, respectively). 84 is configured to be disposed slightly inside the both ends of the radiation conductor 82), and FIG. 8E (configuration in which the radiation conductor 82 has a U-shape on the circuit board 81 side). The shape shown may be used, and the same effect as described above can be obtained. In addition, just because the distance from the end of the ground conductor to the feeding point is longer than ¼ L, the effect of the present invention is not lost at all, but the amount of canceling of the casing current increases, so Since it becomes difficult to improve the antenna at the time, the feeding point is not arranged at such a position.

  Note that the cellular phone can be used in various types such as a folding type, a straight type, and a sliding type.

  The present invention can be applied to various antenna devices and wireless communication devices using the antenna devices.

It is a figure which shows the antenna apparatus by the 1st Embodiment of this invention, (a) is a perspective view of the mobile telephone incorporating the antenna apparatus, (b) is the position of the antenna apparatus and circuit board inside a mobile telephone It is a figure which shows a relationship, (c) is the figure which showed the relationship with the radio | wireless part of an antenna apparatus. (A), (b) is the figure which showed the impedance of the 1st radio | wireless part and the 2nd radio | wireless part. FIG. 1C (a) is a diagram simply showing the configuration of the first radio unit and the second radio unit, and FIG. 1C (b) shows an example of the matching circuit in FIG. 1C (a). FIG. 1D (a) and (b) are diagrams illustrating an arrangement example of a ground pattern (ground conductor) and a circuit board. It is a figure which shows the antenna apparatus by the 2nd Embodiment of this invention. FIG. 2A (a) is a front view of a foldable mobile phone incorporating an antenna device, and FIG. 2A (b) is a diagram illustrating an arrangement example of the antenna device in the mobile phone. FIG. 2B is a diagram illustrating a relationship between the antenna device and the wireless unit. 2C (a) and 2 (b) are views showing the positional relationship between the radiation conductor and the second housing (the housing on which the antenna is not disposed) in the opened state and the closed state of the mobile phone. It is. It is a figure which shows the example of 1 structure of a 1st signal selection means and a 2nd signal selection means. It is a figure which shows the antenna apparatus by the 3rd Embodiment of this invention. FIG. 3A is a front view of a foldable mobile phone incorporating an antenna device. FIG. 3B is a diagram showing the position of the antenna device in the mobile phone. FIG. 3C is a diagram illustrating a relationship between the antenna device and the wireless unit. FIG. 3D (a) is a flowchart showing the switching procedure of each switching unit, and FIG. 3 (b) is an explanatory diagram regarding the state. It is a figure which shows the antenna apparatus by the 4th Embodiment of this invention. FIG. 4A is a front view of a foldable mobile phone incorporating the antenna device. FIG. 4B is a diagram showing the position of the antenna device in the mobile phone. FIG. 4C is a diagram illustrating a relationship between the antenna device and the radio unit. FIG. 4D is a diagram illustrating a configuration of the switching device. FIG. 4E is a flowchart showing a control method of the switching device. It is a figure which shows the antenna apparatus by the 5th Embodiment of this invention. FIG. 5A is a front view of a foldable mobile phone incorporating an antenna device. FIG. 5B is a diagram showing the position of the antenna device in the mobile phone. FIG. 5C is a diagram illustrating a relationship between the antenna device and the wireless unit. (A) is the flowchart figure which showed the operation | movement of the switching part. (B) is a diagram illustrating states 1 and 2; It is a figure which shows the antenna apparatus by the 6th Embodiment of this invention. FIG. 6A is a front view of a foldable mobile phone incorporating an antenna device. FIG. 6B is a diagram showing the position of the antenna device in the mobile phone. FIG. 6C is a diagram illustrating a relationship between the antenna device and the radio unit. FIG. 6D is a diagram showing a configuration of the switching device. It is a figure which shows the antenna apparatus by the 7th Embodiment of this invention. FIG. 7A is a perspective view of a mobile phone with a built-in antenna device. FIG. 7B is a diagram showing the positional relationship between the antenna device inside the mobile phone and the circuit board. FIG. 7C is a diagram illustrating a relationship between the antenna device and the radio unit. FIG. 7D shows the meander shape of the radiation conductor in FIG. 7C. It is a figure which shows the example of 1 structure of the antenna device by the 8th Embodiment of this invention. It is a figure which shows the example of 1 structure of the antenna device by the 8th Embodiment of this invention, and is the 1st modification of FIG. 8A. It is a figure which shows the example of 1 structure of the antenna device by the 8th Embodiment of this invention, and is the 2nd modification of FIG. 8A. It is a figure which shows the example of 1 structure of the antenna device by the 8th Embodiment of this invention, and is the 3rd modification of FIG. 8A. It is a figure which shows the example of 1 structure of the antenna device by the 8th Embodiment of this invention, and is the 4th modification of FIG. 8A.

Explanation of symbols

Case ... 11
First housing 21, 31, 41, 51, 61
Second housing 22, 32, 42, 52, 62
Radiation conductor ... 12, 23, 33, 43, 53, 63, 72, 82
Circuit board ... 13, 73, 81
First circuit board 24, 34, 44, 54, 64
Second circuit board 27, 37, 47, 57, 67, 77
Key part ... 25, 35, 45, 55, 65
Display unit ... 26, 36, 46, 56, 66
Hinge part ... 28, 38, 48, 58, 68
Thin coaxial line ... 29, 39, 49, 59
FPC ... 49,69
First filter 214, 410, 510, 610
Second filter 215, 411, 511, 611
First radio unit 14, 212, 312, 412, 74
2nd radio | wireless part ... 15,213,313,413,75
Radio part ... 513,613
Control unit 314, 415, 514, 614
Switching device ... 414,615
Switching unit ... 512, 612
Switch ... 416, 620
Coil ... 417, 618
Capacitors ... 418, 619
First transmission circuit 16
Second transmission circuit 110
First receiving circuit 17
Second receiving circuit 111
First duplexer ... 18
Second duplexer ... 112
First matching circuit 19
Second matching circuit 113
Open / close detection means 419
Magnet ... 420

Claims (14)

An antenna device having a radiating conductor disposed opposite to a ground conductor with a certain space therebetween,
The radiation conductor is fed from the first radio unit using the first frequency in the first power feeding unit, and further from the second radio unit using a second frequency different from the first frequency. Power is supplied by a second power supply unit, the impedance of the first radio unit at the second frequency is low impedance, and the impedance of the second radio unit at the first frequency is high impedance. A feature antenna device. An antenna device having a radiating conductor disposed opposite to a ground conductor with a certain space therebetween,
The radiation conductor is fed from the first radio unit using the first frequency in the first power feeding unit, and further from the second radio unit using the second frequency different from the first frequency. 2 is fed at the feeding section,
First signal selection means provided between the first radio section and the radiation conductor; and second signal selection means provided between the second radio section and the radiation conductor. Have
At least one of a distance from one end of the ground conductor to the first power feeding unit and a distance from one end of the ground conductor to the second power feeding unit is the radiation conductor in the ground conductor. The antenna device is characterized by being shorter than ¼ of the length of one side facing to each other. The first signal selection unit connects the first radio unit and the radiation conductor via a first filter having a low impedance at the first frequency and a high impedance at the second frequency. ,
The second signal selection unit has a low impedance at the first frequency for the radiation conductor connected to the second radio unit inside the second signal selection unit, and at the second frequency, The antenna device according to claim 2, wherein the antenna device is connected to the ground conductor via a second filter having high impedance. The first signal selection means is a switch that switches between at least two states including a state in which the radiation conductor and the first radio unit are connected and a state in which the first wireless unit is disconnected.
The second signal selection means disconnects the state connecting the radiation conductor and the second radio unit, the radiation conductor and the second radio unit, and the radiation conductor and the ground conductor. The antenna device according to claim 2, wherein the antenna device is a switch that switches between at least two states including a state of connecting the two. Providing a load switching unit between the second filter and the ground conductor;
The antenna device according to claim 3, wherein the load switching unit switches a load connection state between the second filter and the ground conductor.   6. The antenna device according to claim 3, wherein the first filter and the second filter have the same frequency characteristic.   By designing the electrical length of the radiating conductor to be ½ wavelength of the first frequency and ¼ wavelength of the second frequency, the radiating conductor is deformed in the first radio unit. 7. The antenna according to claim 1, wherein the antenna is operated as a half-wavelength folded monopole antenna, and the second radio unit is operated as a quarter-wavelength inverted L antenna. apparatus.   The first radio unit and the second radio unit are integrated into one radio unit, the integrated radio unit is connected to the first power feeding unit at the first frequency, and the second radio unit 8. The antenna device according to claim 1, further comprising a signal switching unit connected to the second power feeding unit at a frequency of 8 MHz. 9. It has an antenna device given in any 1 paragraph of Claims 1-8,
The upper end portion of the first housing containing the key operation portion and the first circuit board and the lower end portion of the second housing containing the display portion and the second circuit board are connected by the hinge portion. In the portable radio device in which the upper end portion of the first circuit board and the lower end portion of the second circuit board are connected by the upper and lower board connecting means,
A portable wireless device, wherein the radiation conductor is disposed at an upper end of the first casing. The first power feeding portion is disposed at one end of the upper end portion of the first circuit board, and the second power feeding portion is disposed at one end on the opposite side of the upper end portion of the first circuit board. In portable radios,
10. The portable wireless device according to claim 9, wherein the upper and lower substrate connecting means are connected to one end side on the power feeding portion side having a higher frequency to be used at the upper end portion of the first circuit board. It has an antenna device given in any 1 paragraph of Claims 1-8,
The upper end portion of the first housing containing the key portion and the first circuit board and the lower end portion of the second housing containing the display portion and the second circuit board are connected by a hinge portion. In the portable radio device in which the upper end portion of the first circuit board and the lower end portion of the second circuit board are connected by an upper and lower board connecting device,
A portable wireless device, wherein the radiation conductor is disposed at a lower end portion of the second casing. The first power feeding portion is disposed at one end of the lower end portion of the second circuit board, and the second power feeding portion is disposed at one end on the opposite side of the lower end portion of the second circuit board;
12. The portable wireless device according to claim 11, wherein the upper and lower substrate connecting means is connected to one end side on the power feeding portion side having a higher frequency to be used at the lower end portion of the first circuit board.   A straight-type communication radio device comprising the antenna device according to any one of claims 1 to 8.   9. A sliding communication radio device comprising the antenna device according to claim 1 mounted thereon.

Images