JP4645603B2 - Antenna structure and wireless communication apparatus including the same - Google Patents

Description

  The present invention relates to an antenna structure provided in a wireless communication apparatus such as a mobile phone and a wireless communication apparatus including the antenna structure.

  The radiation electrode functioning as an antenna performs wireless communication by resonating at a predetermined frequency band. In some cases, this single radiation electrode can support wireless communication in a plurality of frequency bands. As one method for causing a single radiation electrode to perform wireless communication in a plurality of frequency bands, for example, a means for switching and changing the reactance of a portion of the radiation electrode where the electric field is strong is connected to the radiation electrode. By changing the reactance of the strong part of the electric field of the radiation electrode by this means, the electrical length (electric length) of the radiation electrode that determines the resonance frequency of the radiation electrode is switched, and thereby the resonance frequency of the radiation electrode is changed. Switch. By switching the resonance frequency, wireless communication in a plurality of frequency bands is possible with one radiation electrode.

  Further, as another method for causing one radiating electrode to perform wireless communication in a plurality of frequency bands, for example, a means for switching and changing the reactance of a strong magnetic field portion of the radiating electrode is connected to the radiating electrode. In this case, the electrical length of the radiating electrode is switched and the resonance frequency of the radiating electrode is switched in the same manner as described above due to the change in the reactance of the portion where the magnetic field of the radiating electrode is strong. By switching the resonance frequency, wireless communication in a plurality of frequency bands is possible with one radiation electrode.

  As another method, a resonance frequency switching circuit is provided in the radiation electrode itself, and the electrical length of the radiation electrode is switched and changed by the circuit to switch the resonance frequency of the radiation electrode. Some wireless communication is possible.

  Still another method is as follows. That is, the radiation electrode has a plurality of resonance frequencies such as a basic resonance frequency and a higher-order frequency that is a frequency obtained by multiplying the basic resonance frequency by an integer. There is a method of performing wireless communication in a plurality of frequency bands with one radiation electrode using the fundamental resonance frequency and the higher-order resonance frequency of the radiation electrode.

JP-A-11-136025 JP 2001-53543 A JP 11-68456 A JP 2003-179426 A

  As described above, various methods have been proposed for causing wireless communication in a plurality of frequency bands with one radiation electrode. However, there is a problem in impedance matching between the radiation electrode and the wireless communication circuit (high frequency circuit) of the wireless communication device electrically connected to the radiation electrode, or the bandwidth of the frequency band due to the resonance operation of the radiation electrode. There are various problems, such as not enough, switching width of the resonance frequency of the radiation electrode is small, and it is difficult to adjust all resonance frequencies that change the radiation electrode to the set frequency. It wasn't.

  The present invention has been made to solve the above-mentioned problems, and its object is to easily cope with wireless communication in a plurality of frequency bands and to obtain satisfactory antenna matching conditions. It is an object to provide an antenna structure that can be used and a wireless communication apparatus including the antenna structure.

In order to achieve the above object, the present invention has the following configuration as means for solving the above problems. That is, the antenna structure of the present invention is
A mounting substrate on which a ground electrode and a circuit for wireless communication are formed;
A dielectric substrate disposed on an edge of the mounting substrate;
A high-side feed radiation electrode that functions as an antenna by resonating in a higher frequency band of at least two predetermined frequency bands for wireless communication provided on the dielectric substrate;
A high-side feed electrode connected to a predetermined feed section at the edge of the high-side feed radiation electrode;
One end side is connected to the feeding portion of the high-side feeding radiation electrode via the high-side feeding electrode, and the other end side is connected to the high-side connecting portion with the radio communication circuit side, and the feeding portion of the high-side feeding radiation electrode Directly or via a capacitance unit, a high-side power supply conduction path that conducts the signal of the higher frequency band by connecting to a wireless communication circuit, and
A short circuit for directly connecting at least one of the feeding radiation electrode edge portions on both sides of the feeding portion of the feeding radiation electrode on the high side directly to the ground electrode;
A lower frequency band of the predetermined at least two frequency bands for wireless communication provided on the dielectric substrate together with the high-side power-feeding radiation electrode in a state adjacent to the high-side power-feeding radiation electrode with a space therebetween A low-side feed radiation electrode that resonates and functions as an antenna,
A low-side power supply electrode connected to a predetermined power supply portion at an edge of the low-side power supply radiation electrode; and
One end side is connected to the power supply portion of the low-side power supply radiation electrode via the low-side power supply electrode, and the other end side is connected to the low-side connection portion with the circuit for wireless communication, and the power supply portion of the low-side power supply radiation electrode Is connected to a wireless communication circuit through an inductance section, and a low-side power supply conduction path for conducting a signal in the lower frequency band, and
A reactance circuit for connecting at least one feeding radiation electrode edge portion on both sides of the feeding portion of the low-side feeding radiation electrode to the ground electrode via the inductance portion;
It is characterized by having.

  The radio communication apparatus of the present invention is characterized in that an antenna structure having a characteristic configuration in the present invention is provided.

  According to the antenna structure of the present invention, the high-side feeding radiation electrode that performs wireless communication in the higher frequency band of at least two frequency bands for predetermined wireless communication, and the lower frequency band A low-side feeding radiation electrode for performing wireless communication is provided separately. For this reason, since the configuration relating to radio communication in the higher frequency band for radio communication and the configuration relating to radio communication in the lower frequency band can be designed almost independently, the design of the antenna structure is simplified. In the antenna structure of the present invention, it is easy to widen the frequency interval between the lower frequency band and the higher frequency band for wireless communication to one octave or more, or conversely to make it smaller.

  Furthermore, in the antenna structure of the present invention, the high-side feeding radiation electrode is connected to a mounting substrate (for example, a wireless communication device such as a portable telephone) from the edge of the feeding radiation electrode on at least one side on both sides of the feeding unit via a short circuit. The circuit board is provided with a configuration that is connected at high frequency to a ground electrode of a circuit board provided in the housing. For this reason, when the frequency band for radio communication of the antenna structure is in the range of about 800 MHz band to about 2 GHz band used in, for example, a portable phone, the high-side feeding radiation electrode is about 1.7 GHz to Resonant operation over a wide frequency range of 2 GHz. That is, it is possible to widen the frequency band of the high-side feeding radiation electrode.

  Furthermore, in the present invention, the high-side feed radiation electrode and the low-side feed radiation electrode are provided on the dielectric substrate. For this reason, the high-side and low-side feed radiation electrodes can be downsized by the wavelength shortening effect of the dielectric. In the antenna structure of the present invention, separate feed radiation electrodes corresponding respectively to the higher frequency band and the lower frequency band for wireless communication are provided. Since the size can be reduced, an increase in the size of the antenna structure can be suppressed.

  Further, in the present invention, an inductance part is interposed in the low-side power supply conducting path, and the reactance of the inductance part is given to the low-side power supply radiation electrode, and the electric power of the low-side power supply radiation electrode is Increase the length (electric length). As a result, the resonance frequency of the low-side feeding radiation electrode is lowered by an amount corresponding to the given reactance value, so that the low-side feeding radiation electrode can be reduced in size while being set in the lower frequency band. Wireless communication can be performed. This is also an element that can suppress the increase in size of the antenna structure.

  Furthermore, the present invention has a configuration in which at least one side (part distant from the power supply unit) of both sides of the power supply unit in the low-side power supply radiation electrode is connected to the ground electrode via a reactance circuit having an inductance unit. ing. With this configuration, not only the inductance portion provided in the low-side power supply conduction path but also the inductance portion of the reactance circuit is involved in impedance matching between the low-side power supply radiation electrode and the wireless communication circuit side. Will be. Since the inductance part of the low-side power supply conduction path and the inductance part of the reactance circuit have high impedance for the high-side power supply radiation electrode, there is little influence on the resonance operation of the high-side power supply radiation electrode. In addition, the increase in the number of inductance parts involved in impedance matching makes it easy to adjust impedance matching between the low-side power supply radiation electrode and the wireless communication circuit side, and thereby the low-side power supply radiation electrode and This makes it easy to obtain good impedance matching with the wireless communication circuit side.

  Furthermore, in the present invention, at least one side of both sides of the power feeding section in the lower power feeding radiation electrode is connected to the ground electrode via a reactance circuit having an inductance section. Can be widened. That is, when the frequency band for wireless communication of the antenna structure is in the range of about 800 MHz band to about 2 GHz band used in, for example, a portable phone, not only the low-side and high-side feeding radiation electrodes, The ground electrode is also operated as a part of the resonance operation by being induced by the resonance operation of the feeding radiation electrode. In the present invention, at least one side of both sides of the power feeding portion (that is, the portion where the magnetic field is strongest in the power feeding radiation electrode) in the low-side power feeding radiation electrode is connected to the ground electrode via a reactance circuit having an inductance portion. This configuration has a distribution of current flowing in the ground electrode in the direction along the long side of the rectangular circuit board (mounting board) of the portable telephone, for example, during the resonance operation of the ground electrode induced in the feeding radiation electrode Has the effect of dispersing. Thereby, the frequency band of the low-side feeding radiation electrode can be widened.

  In addition, the configuration in which at least one side of both sides of the power supply unit in the low-side power supply radiation electrode is connected to the ground electrode via the reactance circuit, the distribution of the current flowing in the low-side power supply radiation electrode is Also spread. This is also one of the reasons that the frequency band of the low-side feeding radiation electrode can be widened.

  Furthermore, in the configuration of the present invention, as described above, since the ground electrode of the mounting substrate also resonates, there is radio wave radiation from the ground electrode, and this radiation is on the side where the dielectric substrate of the antenna structure is disposed. The mounting board surface side becomes stronger. For this reason, when the antenna structure of the present invention is provided in a mobile phone, a dielectric substrate of the antenna structure is arranged on the substrate surface of the circuit board (mounting board) that becomes the outside (opposite side of the human body side) during a call. By providing, the directivity of the radio wave of the antenna structure can be set on the opposite side of the human body. Thereby, it is possible to suppress the deterioration of the antenna characteristics due to the human body.

  Furthermore, in the present invention, considering that the current distribution of the feeding radiation electrode and the ground electrode during the resonance operation greatly affects the antenna characteristics, and that the current distribution for obtaining good antenna characteristics varies depending on the frequency. In order to obtain good antenna characteristics, as described above, the current distribution of the feed radiation electrode and the ground electrode is made by changing the connection form of the ground electrode in each of the low-side feed radiation electrode and the high-side feed radiation electrode. Is in an appropriate state according to the frequency band. Therefore, good antenna characteristics can be obtained in both the lower frequency band and the higher frequency band for wireless communication.

  By the way, when the miniaturization of the low-side feeding radiation electrode is promoted in accordance with the miniaturization of the mobile phone which is a wireless communication device, for example, the low-side feeding radiation electrode has a lower frequency such as 900 MHz band. When wireless communication is performed in a band, there is a need to perform wireless communication by effectively using a ground electrode having a larger area than the low-side feed radiation electrode in order to compensate for the narrowness of the electrode area of the feed radiation electrode with respect to the frequency. Come. On the other hand, even if the high-side feed radiation electrode is downsized in the same manner as the low-side feed radiation electrode, the high-side feed radiation electrode performs wireless communication in a higher frequency band such as the 2 GHz band. In this case, the high-side feeding radiation electrode mainly performs wireless communication, and the degree of participation in the wireless communication of the ground electrode is small. For this reason, when the high-side feeding radiation electrode performs wireless communication, the resonance operation of the high-side feeding radiation electrode and the user (human body) of a mobile phone that is a wireless communication device, for example, influence each other. There is a risk that the antenna characteristics may be deteriorated. From this, in order to suppress the degree of mutual influence between the high-side feeding radiation electrode and the human body, for example, a ground electrode functioning as a shield member between the high-side feeding radiation electrode and the human body, for example, Is preferably arranged. That is, it is preferable that the high-side feeding radiation electrode is disposed above the ground electrode of the mounting substrate. On the other hand, the antenna characteristic deterioration problem can be suppressed without arranging the low-side feeding radiation electrode above the ground electrode, and the low-side feeding radiation electrode and the ground electrode are characteristic in the present invention. Since the ground electrode can be effectively used for the low-side feeding radiation electrode if the electrical connection is made with a simple connection form, the necessity of arranging the low-side feeding radiation electrode above the ground electrode is small. Therefore, by adopting a configuration in which the ground electrode is not formed in the mounting substrate region corresponding to the region where the low-side feeding radiation electrode is disposed, the electric field of the low-side feeding radiation electrode is easily radiated. It is possible to widen the frequency band of wireless communication with the low-side feeding radiation electrode.

  In addition, the low-side feed radiation electrode is arranged closer to the end of the mounting board than the high-side feed radiation electrode, and the low-side feed radiation electrode has a shorter feed section than the rectangular mounting board. The reactance circuit arranged in a state facing the side and connected to the low-side feeding radiation electrode has a configuration in which the reactance circuit is grounded in the vicinity of the corner portion of the mounting substrate. It is possible to perform wireless communication by effectively using the ground electrode of the mounting board. Thereby, it is possible to further improve the antenna characteristics.

  Furthermore, the dielectric substrate region between the low-side feed radiation electrode formation region and the high-side feed radiation electrode formation region has a configuration in which a hole is formed, thereby providing a low-side feed radiation electrode. And it becomes easy to take isolation from the high-side feeding radiation electrode. Also, the low-side feed radiation electrode and the high-side feed radiation electrode are adjacent to each other with the low-side feed radiation electrode on the short side of the mounting board in the direction along the long side of the rectangular mounting board, for example. In the low-side feeding radiation electrode, the feeding section is set on the side facing the short side of the mounting substrate for both the low-side feeding radiation electrode and the high-side feeding radiation electrode. Since the portion with the strongest electric field and the portion with the strongest magnetic field in the high-side feeding radiation electrode are adjacent to each other with a gap, the low-side feeding radiation electrode and the high-side feeding radiation electrode are electromagnetically connected to each other. Can be prevented from affecting each other.

  Furthermore, by providing a configuration in which the high-side power supply conduction path and the low-side power supply conduction path are connected to a common connection with the wireless communication circuit side, the lower one for wireless communication is provided. The synthesis of the signal in the frequency band and the signal in the higher frequency band becomes easy. In addition, the inductance portion interposed in series with the low-side power supply conduction path has a reactance value of 10 nH to 20 nH, for example, when the lower frequency band for wireless communication is an 800 MHz band, The reactance value of the inductance section has an impedance higher than 50Ω for a signal in a higher frequency band (for example, 2 GHz band) for wireless communication. For this reason, for a signal in the higher frequency band for wireless communication, the inductance portion interposed in series with the low-side power supply conduction path is in an invisible state. As a result, even if the high-side power supply conduction path and the low-side power supply conduction path are connected to the common connection portion with the radio communication circuit side, the resonance operation of the high-side power supply radiation electrode is achieved. The inductance portion of the low-side power supply conduction path hardly has an adverse effect.

  Furthermore, by providing a configuration in which any one of a plurality of inductance portions having different inductance values is selectively switched and electrically connected to the low-side power supply conduction path, Since the resonance frequency of the electrode can be switched, the low-side feeding radiation electrode can be adapted for wireless communication in a plurality of frequency bands. In addition, even if the resonance frequency of the low-side power supply radiation electrode is switched, the reactance values of all the inductance parts that are switched and connected to the low-side power supply conduction path are the same for the higher frequency band signals. Since the values are such that they cannot be seen electrically, there is almost no adverse effect on the resonance operation of the high-side feeding radiation electrode. That is, in the configuration of the present invention, the resonance frequency of the low-side feed radiation electrode can be switched without deteriorating the antenna characteristics of the high-side feed radiation electrode.

  Furthermore, by providing a configuration in which a parasitic radiation electrode is provided corresponding to at least one of the high-side feeding radiation electrode and the low-side feeding radiation electrode, The frequency band can be widened by the double resonance state.

  Furthermore, the dielectric substrate has a configuration in which, in addition to the low-side feeding radiation electrode and the high-side feeding radiation electrode, another feeding radiation electrode is provided, the antenna structure of the present invention is provided. The number of radio communication systems that can be handled can be increased.

  In a wireless communication apparatus having an antenna structure having a specific configuration in the present invention, the antenna structure of the present invention is small but excellent in antenna characteristics, and thus can be easily downsized. High reliability for wireless communication can be obtained.

  Embodiments according to the present invention will be described below with reference to the drawings.

  FIG. 1A shows a schematic perspective view of the antenna structure of the first embodiment, and FIG. 1B shows a schematic cross-sectional view of the AA portion of FIG. Has been. The antenna structure 1 of the first embodiment is provided in a mobile phone that is a wireless communication device. The antenna structure 1 includes a mounting substrate 2 and a dielectric substrate 3 mounted on the mounting substrate 2. A low-side feed radiation electrode 4 provided on the dielectric substrate 3, a low-side feed electrode 5, a high-side feed radiation electrode 6, a high-side feed electrode 7, and a substrate-side feed path provided on the mounting substrate 2. 8, 9, a reactance circuit 10 (10 a, 10 b) connected to the low-side feeding radiation electrode 4, and a short electrode 11 connected to the high-side feeding radiation electrode 6. Details of these components of the antenna structure 1 will be described next.

  That is, the mounting board 2 constituting the antenna structure 1 of the first embodiment is a circuit board built in the casing of the mobile phone, and has a rectangular shape having a short side 2s and a long side 2t. Yes. On the mounting substrate 2, the ground electrode G is provided on almost the entire surface, and a wireless communication circuit 13 is formed. The mobile phone provided with the antenna structure 1 of the first embodiment has a function capable of wireless communication in two different frequency bands such as 900 MHz band and 2 GHz band. For this reason, as shown in FIGS. 2A to 2C, the wireless communication circuit 13 of the mobile phone according to the first embodiment includes a low-side wireless communication circuit portion 13L and a high-side wireless communication circuit portion 13L. And a wireless communication circuit unit 13H. The low-side wireless communication circuit unit 13L has a lower frequency band of a predetermined lower frequency band for wireless communication (for example, 900 MHz band) and a higher frequency band (for example, 2 GHz band). A circuit configuration for performing signal processing such as signal modulation and demodulation is provided. The high-side wireless communication circuit unit 13H has a circuit configuration for processing a signal in the higher frequency band.

  In this first embodiment, the dielectric substrate 3 has a rectangular parallelepiped shape. The dielectric substrate 3 is formed at the corners of the mounting substrate 2 and the side surfaces thereof are the short side 2s and the long side 2t of the mounting substrate 2, respectively. It is mounted along. The dielectric substrate 3 includes a low-side feed radiation electrode 4 formation region and a high-side feed radiation electrode 6 formation region. The low-side feed radiation electrode 4 formation region is defined as a short side of the mounting substrate 2. They are arranged on the 2s side (end side) in order along the long side 2t of the mounting substrate 2 with a gap in between. The dielectric substrate 3 has a through-hole 14 that is a hole extending from the top surface 3a to the bottom surface 3d in the gap between the formation region of the low-side feeding radiation electrode 4 and the formation region of the high-side feeding radiation electrode 6. Is formed. The dielectric constant of the dielectric material constituting the dielectric substrate 3 is appropriately set in consideration of the miniaturization of the low-side feeding radiation electrode 4 and the high-side feeding radiation electrode 6.

  The low-side feed radiation electrode 4 functions as an antenna by resonating in the lower frequency band for wireless communication. In the first embodiment, the low-side feed radiation electrode 4 is constituted by a conductor plate, and the dielectric base 3 And has a shape extending from the upper surface 3a to the front surface 3f shown in FIG. 1 (a). In the low-side power supply radiation electrode 4, the position of the power supply unit 4 </ b> Q is set in advance at an edge portion facing the short side 2 s of the mounting substrate 2. One end side of the lower power supply electrode 5 is connected to the power supply section 4Q. The other end of the low-side power supply electrode 5 is connected to one end of a substrate-side power supply path 8 described below. The low-side power supply electrode 5 is formed of the same conductive plate as that of the low-side power supply radiation electrode 4.

  The board-side power supply path 8 is provided on the mounting board 2, and one end side thereof is connected to the low-side power supply electrode 5 as described above, and the other end side is connected to the low-side connection portion PL. Inductive portion 15 is interposed in this. The substrate-side power supply path 8 and the low-side power supply electrode 5 constitute a low-side power supply conduction path 16 that conducts a signal in the lower frequency band for wireless communication. The low-side power supply conduction path 16 is connected to the low-side radio communication circuit unit 13L through the low-side connection unit PL, for example, in a connection form as shown in FIGS. Is done. That is, in the example of FIG. 2A, the low-side power supply conduction path 16 is directly connected to the low-side wireless communication circuit unit 13L via the low-side connection unit PL. In the example of FIG. 2B, the low-side power supply conducting path 16 is connected to the low-side radio communication circuit unit 13L through the low-side connection unit PL and further through the high-low switching unit 17. The Further, in the example of FIG. 2C, the low-side power supply conduction path 16 is connected to the low-side radio communication circuit unit 13L through the low-side connection unit PL and further through the diplexer 18. The high / low changeover switch means 17 is configured to electrically switch the antenna structure 1 to either one of the high-side wireless communication circuit unit 13H and the low-side wireless communication circuit unit 13L. It has a configuration for connection. In addition, the diplexer 18 has a configuration for performing multiplexing / demultiplexing between a signal in a higher frequency band for wireless communication and a signal in a lower frequency band for wireless communication by using a difference in frequency of the signal. ing.

  Reactance circuits 10 (10a, 10b) are connected to the electrode edge portions on both sides of the power supply portion 4Q of the low-side power supply radiation electrode 4 via a gap, respectively. The reactance circuit 10 (10a, 10b) includes a stub electrode 20 extended from a predetermined connection portion with the reactance circuit 10 at the edge of the low-side feeding radiation electrode 4, and the stub electrode 20 A substrate-side ground path 21 formed on the mounting substrate 2 for grounding to the ground electrode G and an inductance portion 22 interposed in the substrate-side ground path 21 are configured. The reactance values of the inductance part 22 of the reactance circuit 10 and the inductance part 15 of the low-side power supply conduction path 16 are caused to cause the low-side power supply radiation electrode 4 to resonate in the lower frequency band for wireless communication. Thus, it is set in consideration of performing wireless communication and impedance matching between the low-side feeding radiation electrode 4 and the low-side wireless communication circuit unit 13L.

  The high-side feeding radiation electrode 6 functions as an antenna by resonating in the higher frequency band for wireless communication. In the first embodiment, the high-side feeding radiation electrode 6 is composed of a conductor plate, It is disposed on the upper surface 3a with a low-side feeding radiation electrode 4 therebetween. The position of the power feeding portion 6Q is set in advance at the edge of the high-side power feeding radiation electrode 6 on the short side 2s side of the mounting substrate 2. One end side of the high-side power supply electrode 7 is connected to the power supply portion 6Q. The high-side power supply electrode 7 is composed of the same conductive plate as the conductive plate constituting the high-side power supply radiation electrode 6. In this first embodiment, the inner wall surface of the through hole 14 of the dielectric substrate 3. It is arranged. An end portion of the high-side power supply electrode 7 opposite to the connection end portion with the power supply radiation electrode 6 is connected to one end side of the substrate-side power supply path 9. The other end side of the board-side power supply path 9 is connected to the high-side connection portion PH. The substrate-side power supply path 9 and the high-side power supply electrode 7 constitute a high-side power supply conduction path 24 that conducts a signal in the higher frequency band for wireless communication. The high-side power supply conduction path 24 is connected to the high-side wireless communication circuit unit 13H via the high-side connection unit PH in the connection form shown in FIGS. 2 (a) to 2 (c). Connected.

  The short electrode 11 is for electrically connecting the electrode edge portion of the high-side power supply radiation electrode 6 in the vicinity of the power supply portion 6Q to the ground electrode G of the mounting substrate 2. The stub electrode 26 is formed to extend from the edge of the feed radiation electrode 6 toward the mounting substrate 2 along the inner wall surface of the through hole 14. This short electrode 11 (26) is formed on the mounting substrate 2 and has a conduction path (not shown) connecting the extended tip side of the short electrode 11 and the ground electrode G, as well as feeding the high-side feeding radiation electrode 6. A short circuit is formed in which at least one of the feeding radiation electrode edge portions on both sides of the portion 6Q is directly grounded to the ground electrode G.

  The antenna structure 1 of the first embodiment is configured as described above. In the first embodiment, the high-side power supply conduction path 24 electrically connects the power supply unit 6Q of the high-side power supply radiation electrode 6 directly to the high-side wireless communication circuit unit 13H. However, as shown in FIG. 3, by providing a capacitance portion 27 in the substrate-side power supply path 9, the high-side power supply conduction path 24 connects the power supply section 6 </ b> Q of the high-side power supply radiation electrode 6. It is good also as a structure connected to the circuit part 13H for high side radio | wireless communication via the capacitance part 27. FIG. In this case, the matching state between the high-side feeding radiation electrode 6 and the high-side radio communication circuit unit 13H can be adjusted by adjusting the capacitance of the capacitance unit 27. Impedance matching between the feeding radiation electrode 6 and the high-side radio communication circuit unit 13H is facilitated.

  In the first embodiment, separate connection portions PL and PH are provided corresponding to the low-side power supply conduction path 16 and the high-side power supply conduction path 24, respectively. For example, as illustrated in FIG. 4A, a common connection portion P may be provided in the low-side power supply conduction path 16 and the high-side power supply conduction path 24. In this case, the antenna structure 1 and the wireless communication circuit 13 are connected to each other via a high / low changeover switch means 17 and a diplexer 18 as shown in FIGS. 2B and 2C, for example. In addition, a low frequency band signal for wireless communication is supplied from the low-side wireless communication circuit unit 13L to the low-side power supply radiation electrode 4, and a high-side power supply is supplied from the high-side wireless communication circuit unit 13H. In order to make the feeding of the signal in the higher frequency band for wireless communication to the radiation electrode 6 more independent, for example, as shown in FIG. The switch means 28 may be interposed in the substrate side power supply path 8. The switch means 28 is controlled to be in a switch-on state when performing radio communication of a lower frequency band signal for radio communication, for example, by a control circuit of the radio communication device, and the higher frequency band signal for radio communication is controlled. When the wireless communication is performed, the switch is controlled to be off. Further, a switch unit may be provided that selectively switches one of the low-side power supply conduction path 16 and the high-side power supply conduction path 24 to the common connection portion P. The switch means is configured so that the common connection portion P is switched and connected to the low-side power supply conduction path 16 when wireless communication of a signal in the lower frequency band for wireless communication is performed by the control circuit of the wireless communication device. When the wireless communication of the signal in the higher frequency band for wireless communication is performed, the common connection portion P is controlled to be switched and connected to the high-side power supply conduction path 24.

  The second embodiment will be described below. In the description of the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the duplicate description of the common portions is omitted.

  In the antenna structure 1 of the second embodiment, as shown in the schematic exploded view of the antenna structure in FIG. 5, the ground electrode G is provided in the mounting substrate region corresponding to the region where the low-side feeding radiation electrode 4 is disposed. Is not formed. Other configurations of the antenna structure 1 of the second embodiment are the same as those of the antenna structure 1 of the first embodiment. In FIG. 5, illustration of the substrate-side power supply paths 8 and 9, the substrate-side ground path 21, the inductance portions 15 and 22, and the like formed on the mounting substrate 2 is omitted.

  The third embodiment will be described below. In the description of the third embodiment, the same components as those in the first and second embodiments are denoted by the same reference numerals, and a duplicate description of the common portions is omitted.

  FIG. 6 schematically shows the antenna structure 1 of the third embodiment. In the antenna structure 1 of the third embodiment, a parasitic radiation electrode 30 and a ground electrode 31 are provided on the dielectric substrate 3 in addition to the configurations of the first and second embodiments. The parasitic radiation electrode 30 is disposed on the upper surface 3a of the dielectric substrate 3 so as to be adjacent to the high-side feeding radiation electrode 6 with a space therebetween. The parasitic radiation electrode 30 is electromagnetically coupled to the high-side feeding radiation electrode 6. It is configured to combine to create a double resonance state. The grounding electrode 31 is disposed adjacent to the high-side power supply electrode 7 on the inner wall surface of the through hole 14 of the dielectric substrate 3 with a space therebetween, and one end side of the grounding electrode 31 is the non-feeding radiation electrode 30. And the other end of the grounding electrode 31 is electrically connected to the ground electrode G.

  In the example of FIG. 6, the non-feeding radiation electrode 30 that creates a double resonance state with the high-side feeding radiation electrode 6 is provided. A parasitic radiation electrode that creates a state may also be provided. In addition, when the frequency band of wireless communication by the high-side feeding radiation electrode 6 has a desired bandwidth and the frequency band of wireless communication by the low-side feeding radiation electrode 4 is widened, for example, The non-feeding radiation electrode 30 corresponding to the feeding radiation electrode 6 may be omitted, and only the non-feeding radiation electrode that creates a double resonance state with the low-side feeding radiation electrode 4 may be provided.

  The fourth embodiment will be described below. In the description of the fourth embodiment, the same components as those in the first to third embodiments are denoted by the same reference numerals, and duplicate descriptions of the common portions are omitted.

  FIG. 7 schematically shows the antenna structure of the fourth embodiment. In the fourth embodiment, a plurality of inductance portions 15 (15a, 15b) having different inductance values are interposed in parallel on the substrate-side power supply path 8 of the low-side power supply conduction path 16. . The board-side power supply path 8 is provided with inductance switching means 33 for selectively connecting one of the inductance portions 15 (15a, 15b) to the connection portion P. The inductance switching unit 33 is controlled to be switched by, for example, a control circuit of the wireless communication device. In the fourth embodiment, the resonance frequency of the low-side feeding radiation electrode 4 is switched by switching the inductance portions 15a and 15b. Thereby, the frequency band of the wireless communication by the low-side feeding radiation electrode 4 can be switched. Other configurations of the antenna structure 1 of the fourth embodiment are the same as those of the above-described embodiment as shown in FIGS. 1 and 3 to 6.

  In the example of FIG. 7, the two inductance portions 15 (15 a, 15 b) are provided in parallel in the substrate-side power supply path 8 of the low-side power supply conduction path 16. In FIG. 8, three or more inductance portions 15 may be interposed in parallel. In this case, there is provided switching means for selectively switching any one of all the inductance parts of the parallel connection to conduct the signal.

  The fifth embodiment will be described below. In the description of the fifth embodiment, the same components as those in the first to fourth embodiments are denoted by the same reference numerals, and duplicate descriptions of common portions are omitted.

  In the antenna structure 1 of the fifth embodiment, as shown in FIG. 8, the dielectric substrate 3 includes a feed radiation electrode in addition to the low-side feed radiation electrode 4 and the high-side feed radiation electrode 6. 35, a power supply electrode 36, and a stub electrode 37 are provided. The feed radiation electrode 35 performs wireless communication in a frequency band different from that of the feed radiation electrodes 4 and 6. One end side of the feeding electrode 36 is connected to the feeding radiation electrode 35, and the other end side is electrically connected to a wireless communication circuit unit for the feeding radiation electrode 35 in the wireless communication circuit 13 of the wireless communication device. The stub electrode 37 is disposed adjacent to the power supply electrode 36 with a space therebetween. The stub electrode 37 has one end connected to the power supply radiation electrode 35 and the other end electrically connected to the ground electrode G. .

  Other configurations of the antenna structure 1 of the fifth embodiment are the same as those of the above-described embodiment as shown in FIG. 1 and FIGS.

  The sixth embodiment will be described below. In the description of the sixth embodiment, the same components as those in the first to fifth embodiments are denoted by the same reference numerals, and the duplicate description of the common portions is omitted.

  In the antenna structure 1 according to the sixth embodiment, instead of providing the inductance portion 15 in the substrate-side feeding path 8, as shown in FIG. 9A, the low-side feeding electrode made of a conductor plate is used. 5 is formed in a shape having an inductance value, and the low-side feeding electrode 5 can function as the inductance portion 15. Further, in the reactance circuit 10 (10a, 10b), the stub electrode 20 made of a conductor plate is formed in a shape having an inductance value instead of providing the inductance portion 22 in the substrate-side ground path 21, and the stub electrode 20 is formed. Is configured to function also as the inductance portion 22.

  Other configurations of the antenna structure 1 of the sixth embodiment are the same as those of the above-described embodiment as shown in FIG. 1 and FIGS. 3 to 8. When the capacitance part 27 is interposed in the high-side power supply conduction path 24, for example, instead of interposing the capacitance part 27 in the board-side power supply path 9, FIG. As shown, the high-side power supply electrode 7 made of a conductor plate may be formed in a shape having a capacity, and a capacitance portion 27 may be interposed in the high-side power supply electrode 7.

  As in the sixth embodiment, the inductance portions 15 and 22 are formed by the same conductor plate as the conductor plate constituting the low-side feed radiation electrode 4, or the high-side feed radiation electrode 6 is constructed. By forming the capacitance portion 27 with the same conductive plate as the conductive plate, the effect that the antenna structure 1 having good antenna characteristics can be provided stably can be obtained. That is, the inductance units 15 and 22 and the capacitance unit 27 are greatly involved in the antenna characteristics, and the inductance units 15 and 22 and the capacitance unit 27 preferably have a preset reactance value. However, if the inductance portions 15 and 22 and the capacitance portion 27 are configured separately from the power supply radiation electrodes 4 and 6 by, for example, circuit elements, the inductance portions 15 and 22 and the capacitance portion 27 are caused by, for example, performance variations of components. The reactance value may deviate from the set value, which may deteriorate the antenna characteristics. In contrast, by configuring the inductance portions 15 and 22 and the capacitance portion 27 integrally with the feeding radiation electrodes 4 and 6 by a conductor plate, the above-described problem of deterioration of the antenna characteristics can be suppressed, and a good antenna can be obtained. The antenna structure 1 having characteristics can be provided stably.

  In addition, this invention is not limited to the form of each 1st-6th embodiment, It can take various embodiment. For example, in each of the first to sixth embodiments, the short-side electrode 11 (short circuit) is connected to the high-side feed radiation electrode 6 at the electrode edge portion on only one side of both sides of the feed portion 6Q. However, for example, as illustrated in FIG. 10, the short electrode 11 (short circuit) may be connected to the electrode edge portions on both sides of the power feeding unit 6 </ b> Q.

  In each of the first to sixth embodiments, the reactance circuit 10 is connected to the electrode edge portions on both sides of the power supply section 4Q in the low-side power supply radiation electrode 4, but FIG. As shown in FIG. 4, the reactance circuit 10 may be connected to only one electrode edge portion of the both sides of the power feeding section 4Q.

  Further, in addition to the configuration of the low-side feeding radiation electrode 4 shown in each of the first to sixth embodiments, the electrical length of the low-side feeding radiation electrode 4 as shown in FIG. A slit 40 that lengthens the length may be provided in the low-side feeding radiation electrode 4. By providing the slit 40, it is possible to reduce the size of the power feeding radiation electrode 4 on the lower side. In other words, the shortage of the electrical length of the low-side feed radiation electrode 4 (in other words, the lack of size) can be resolved without increasing the size of the low-side feed radiation electrode 4. The resonance operation in the lower frequency band can be performed by the low-side feeding radiation electrode 4. The design items such as the number of slits 40 formed, the positions of the slits 40, the slit shape, and the slit size are the size of the low-side feeding radiation electrode 4, the frequency of the lower frequency band for wireless communication set in advance, It is appropriately designed in consideration of various electrical lengths such as the current distribution of the low-side feeding radiation electrode 4, and is not limited to the example of FIG.

  Further, in addition to the configuration of the low-side feeding radiation electrode 4 shown in each of the first to sixth embodiments, for example, a multiband slot 41 as shown in FIG. The feeding radiation electrode 4 may be formed. Since the slot 41 is formed in the low-side feed radiation electrode 4, the frequency band in which the low-side feed radiation electrode 4 can perform wireless communication can be increased, and this is compatible with multibanding. It becomes easy. The formation position, shape, size, and the like of the slot 41 are not limited to the example of FIG. 12B, and the current distribution of the low-side feeding radiation electrode 4 and the low-side feeding radiation electrode 4 The frequency is set appropriately in consideration of various points related to the resonance operation of the power feeding radiation electrode 4 on the lower side such as the required frequency band for a plurality of wireless communication and the electrode area.

  Further, the low-side feeding radiation electrode 4 may be configured as shown in FIG. That is, in the example of FIG. 12C, the low-side feeding radiation electrode 4 branches into a plurality of positions at a position on the way from the feeding section 4Q toward the radiation electrode end that is the terminal side of the current conduction path. The shape has a plurality of branch radiation electrode portions 4a, 4b, 4c having different resonance frequencies. Since the low-side feeding radiation electrode 4 has such a branched shape, wireless communication in a plurality of different frequency bands can be performed. Thereby, the low-side feeding radiation electrode 4 corresponds to the multiband. Note that the branch position in the low-side feeding radiation electrode 4, the shape of the branch radiation electrode portions 4a, 4b, and 4c, the number of branch radiation electrode portions formed, and the like are the number of wireless communication frequency bands determined in advance. The frequency band is appropriately set in consideration of the frequency characteristics, the antenna characteristics such as the frequency band width and the antenna gain, and is not limited to the example of FIG.

  Furthermore, as shown in FIG. 13A, an upward inclination may be given to a part of the upper surface 3a of the dielectric substrate 3 or the entire upper surface 3a. Further, as shown in FIG. 13B, the dielectric substrate 3 is disposed on the mounting substrate 2 with a part thereof protruding from the end edge of the mounting substrate 2, and the protruding portion of the dielectric substrate 3 A protruding portion 3T that protrudes downward may be formed at the bottom of the. When the upper surface 3a of the dielectric substrate 3 is inclined upward or when the dielectric substrate 3 is provided with the protruding portion 3T, the inclined portion or the protruding portion 3T is formed. As a result, the volume of the dielectric substrate 3 increases. Since the antenna characteristics involve the volume of the dielectric substrate 3, the antenna characteristics can be improved by increasing the volume of the dielectric substrate 3.

  Furthermore, in each of the first to sixth embodiments, the low-side feeding radiation electrode 4 and the high-side feeding radiation electrode 5 are arranged in order along the long side 2t of the mounting substrate 2, For example, as shown in FIG. 14, the low-side feeding radiation electrode 4 and the high-side feeding radiation electrode 5 are formed with the low-side feeding radiation electrode 4 on the corner side of the mounting board 2. It may be arranged along the short side 2s.

  Further, in each of the first to sixth embodiments, the dielectric substrate 3 penetrates through a region between the formation region of the low-side feeding radiation electrode 4 and the formation region of the high-side feeding radiation electrode 6. Although the hole 14 is provided, a recess (groove) may be provided instead of the through hole 14. Further, if the low-side feeding radiation electrode 4 and the high-side feeding radiation electrode 6 can be sufficiently isolated without providing the through-holes 14 and the recesses, the through-holes 14 and the recesses are omitted. May be.

  Furthermore, in each of the first to sixth embodiments, the ground electrode G is formed on the bottom surface of the mounting substrate 2, but the ground electrode G may be provided on the inner layer of the mounting substrate 2 that is a multilayer substrate. Good. Furthermore, in each of the first to sixth embodiments, the antenna structure 1 is provided in a mobile phone. However, the antenna structure of the present invention may be provided in a wireless communication device other than the mobile phone. The wireless communication apparatus of the present invention is not limited to a portable phone.

It is a figure for demonstrating the antenna structure of the example of 1st Embodiment. It is a figure for demonstrating the example of a connection form of an antenna structure and the circuit for radio | wireless communication. It is a figure showing the modification of the antenna structure of the example of 1st Embodiment. Furthermore, it is a figure showing the modification of the antenna structure of the example of 1st Embodiment. It is a typical exploded view for explaining the antenna structure of the second embodiment. It is a figure for demonstrating the antenna structure of the example of 3rd Embodiment. It is a figure for demonstrating the antenna structure of the example of 4th Embodiment. It is a figure for demonstrating the antenna structure of the example of 5th Embodiment. It is a figure for demonstrating the antenna structure of the example of 6th Embodiment. It is a figure for demonstrating other example embodiments. It is a figure for demonstrating another example of another embodiment. It is a figure for demonstrating another example of another embodiment. Furthermore, it is a figure for demonstrating another example of another embodiment. Furthermore, it is a figure for demonstrating other embodiment examples.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna structure 2 Mounting board 3 Dielectric base | substrate 4 Low side feed radiation electrode 5 Low side feed electrode 6 High side feed radiation electrode 7 High side feed electrode 10 Reactance circuit 11 Short electrode 13 Circuits for wireless communication 15, 22 Inductance section 16 Low-side power supply conduction path 24 High-side power supply conduction path 27 Capacitance section

Claims (10)

A mounting substrate on which a ground electrode and a circuit for wireless communication are formed;
A dielectric substrate disposed on an edge of the mounting substrate;
A high-side feed radiation electrode that functions as an antenna by resonating in a higher frequency band of at least two predetermined frequency bands for wireless communication provided on the dielectric substrate;
A high-side feed electrode connected to a predetermined feed section at the edge of the high-side feed radiation electrode;
One end side is connected to the feeding portion of the high-side feeding radiation electrode via the high-side feeding electrode, and the other end side is connected to the high-side connecting portion with the radio communication circuit side, and the feeding portion of the high-side feeding radiation electrode Directly or via a capacitance unit, a high-side power supply conduction path that conducts the signal of the higher frequency band by connecting to a wireless communication circuit, and
A short circuit for directly grounding at least one of the feeding radiation electrode edge portions on both sides of the feeding portion of the feeding radiation electrode on the high side directly to the ground electrode;
An antenna which is provided on the dielectric substrate in a state adjacent to a high-side feeding radiation electrode with a space therebetween and resonates in a lower one of the predetermined two frequency bands for wireless communication. A functioning low-side feed radiation electrode;
A low-side power supply electrode connected to a predetermined power supply portion at an edge of the low-side power supply radiation electrode; and
One end side is connected to the power supply portion of the low-side power supply radiation electrode via the low-side power supply electrode, and the other end side is connected to the low-side connection portion with the circuit for wireless communication, and the power supply portion of the low-side power supply radiation electrode Is connected to a wireless communication circuit through an inductance section, and a low-side power supply conduction path for conducting a signal in the lower frequency band, and
A reactance circuit that grounds at least one feeding radiation electrode edge portion on both sides of the feeding portion of the low-side feeding radiation electrode to the ground electrode via the inductance portion;
An antenna structure characterized by comprising:   2. The antenna structure according to claim 1, wherein the mounting substrate has a rectangular shape, and the low-side feeding radiation electrode is disposed closer to the end of the mounting substrate than the high-side feeding radiation electrode.   3. The antenna structure according to claim 1, wherein a hole is formed in a region between the low-side feeding radiation electrode and the high-side feeding radiation electrode in the dielectric substrate. The mounting board is a rectangular shape having a short side and a long side, and the power feeding portion of the low-side feeding radiation electrode is configured to face the short side of the mounting board,
The reactance circuit is configured such that at least one of the feeding radiation electrode edge portions on both sides of the feeding portion of the feeding radiation electrode on the low side is connected to the ground electrode portion formed at or near the corner of the mounting substrate via the inductance portion. The antenna structure according to claim 1, wherein the antenna structure is grounded.   The antenna structure according to any one of claims 1 to 4, wherein a ground electrode is not formed in a mounting substrate region corresponding to a region where the low-side feeding radiation electrode is disposed.   The end on the radio communication circuit side of the high-side power supply conduction path is the high-side connection section, and the end on the radio communication circuit side of the low-side power supply conduction path is the high-side connection section. Instead of being connected to separate low-side connection portions, the end portions on the wireless communication circuit side of the high-side power supply conduction path and the low-side power supply conduction path are each a wireless communication circuit. The antenna structure according to any one of claims 1 to 5, wherein the antenna structure is connected to a common connection portion with the side.   A plurality of inductance portions having different inductance values are provided in parallel in the low-side power supply conduction path, and alternatively, one of the inductance portions is low for wireless communication. The antenna structure according to any one of claims 1 to 6, further comprising switching means for switching and conducting a signal in one frequency band.   The dielectric substrate has a high-side non-feeding radiation electrode that is disposed with a gap between the high-side feeding radiation electrode and electromagnetically coupled to the high-side feeding radiation electrode to create a double resonance state, and a low-side feeding radiation. The at least one of a low-side non-feeding radiation electrode that is disposed through an interval with an electrode and electromagnetically couples with a low-side feeding radiation electrode to create a double resonance state is provided. The antenna structure according to any one of claims 1 to 7.   The dielectric substrate functions as an antenna by resonating in a radio communication frequency band different from the radio communication frequency band of the high-side feed radiation electrode and the radio communication frequency band of the low-side feed radiation electrode. The antenna structure according to any one of claims 1 to 8, wherein the feeding radiation electrode is provided separately from the high-side feeding radiation electrode and the low-side feeding radiation electrode.   A wireless communication apparatus comprising the antenna structure according to claim 1.

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