JP2011015034A - Antenna structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact antenna structure having high antenna efficiency and operating at a plurality of frequencies.SOLUTION: In a non-ground region Zp of a substrate 10, first, second and third radiation elements 1, 2 and 3 formed of a band or linear electrodes are disposed. The first radiation element 1 has one end side as a feed connection part to be connected to a feed point 5, and a switch element 7 provided on the other end side. The second radiation element 2 has one end side as a conductor connection part to be connected to a ground conductor, and the other end side connected to the switch element 7. One end side of the third radiation element 3 is connected to the switch element 7, and the other end side is an open end 3a. The switch element 7 switches between low frequency antenna operation where the first and third radiation elements 1 and 3 are electrically coupled through the switch element 7, and high frequency antenna operation where the second and third radiation elements 2 and 3 are electrically coupled through the switch element 7.

Description

  The present invention relates to a small antenna structure applied to a mobile phone or the like.

  In recent years, multiband antenna modules have been used in wireless devices such as mobile phones, and improvements in performance are desired. FIG. 8 shows an example of a multiband antenna structure (see Patent Document 1). In the figure, a parasitic element (sub-element) 41 is disposed in the vicinity of an open end 40 a of a feeding element (main element) 40 connected to a feeding point 39. The parasitic element 41 includes a plurality of folded portions. In this antenna structure, an antenna operation corresponding to a plurality of frequencies can be performed by switching the switch element 40 disposed between the base end portion 41 b of the parasitic element 41 and the ground conductor 50.

  FIG. 9 shows another example of the antenna structure (see Patent Document 2). In the figure, a linear radiating element 46 connected to a feeding point 45 of the ground plane 44 is formed in a folded shape, and a switch element 47 is disposed in the middle of the linear radiating element 46. In this antenna structure, the switch element 47 is switched, and the element 46a, 46b on both sides of the linear radiating element 46 sandwiching the switch element 47 is connected to the feed point 45, and the element 46b is connected to the feed point 45. The antenna operation corresponding to a plurality of resonance frequencies is made possible by switching the state separated from the antenna. Further, in this antenna structure, when the element piece 46b is separated from the feeding point 45 by the switch element 47, the linear radiation element functions as a parasitic reflection element, and the parasitic reflection element (element piece 46b) and The linear radiating element formed by the element piece 46a on the side connected to the feeding point 45 resonates.

W02005 / 069439 JP 2006-54639 A

  By the way, in order to operate the antenna element efficiently in a low frequency band such as the 800 MHz band, it is necessary to increase the antenna size. However, in mobile phone terminals and the like, it is required to reduce the antenna size. In addition, it is difficult to improve antenna efficiency. In particular, as in the antenna structure shown in FIG. 8, it is necessary to secure a space for placing the parasitic element 41 provided independently of the feed element 40 in addition to the placement space for the feed element (main element) 40. As a result, the area of the feed element 40 must be reduced, thereby causing a problem that the antenna efficiency is further deteriorated.

  Further, in the antenna structure shown in FIG. 9, the element piece 46b (parasitic reflection element) is separated from the linear radiating element connected to the feeding point 45 by the switch element 47, and this length is λ / 2 ( It operates at a frequency of λ. Since the antenna size of the element piece 46b is larger than that of a parasitic element operating at λ / 4 whose one end is grounded, there is a problem that it is difficult to reduce the antenna size.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an antenna structure that is small in size, has high antenna efficiency, and can perform antenna operations at a plurality of frequencies.

  In order to achieve the above object, the present invention has the following configuration as means for solving the above problems. That is, the present invention provides a first electrode formed by a strip-like or linear electrode disposed in the non-ground region of a substrate having a ground region where a ground conductor is formed and a non-ground region where no ground conductor is formed. The first radiating element has a power supply connection portion connected at one end side to a power supply point, and a switch element is provided at the other end side. One of the radiating elements is connected to the grounding conductor at one end and the other end is connected to the switch element, and the third radiating element is connected to the switch element at one end and the other end is open. An antenna operation on a low frequency side that is performed by electrically coupling the first radiating element and the third radiating element via the switch element by switching the switch element. The second radiation element And said third radiating element is characterized in that the electrically coupled to switch between the high-frequency side of the antenna operation performed configured through the switching element.

  The present invention also provides a first electrode formed by a strip-like or linear electrode disposed in the non-ground region of a substrate having a ground region where a ground conductor is formed and a non-ground region where no ground conductor is formed. 1st, 2nd, 3rd, and 4th radiating elements, and the first radiating element is formed with a feeding connection portion whose one end is connected to the feeding point, and the first switching element is located on the other end side. The second radiating element is formed as a conductor connecting portion having one end connected to a ground conductor, the other end is branched into two, and one branch end is connected to the first switching element. The other branch end is connected to the second switch element, the third radiating element has one end connected to the second switch element, and the other end is an open end, and the fourth radiating element is One end side is connected to the first switch element, and the other end side is the second switch element. A third switch element that is connected to the switch element and that switches the connection of the second radiating element between the ground conductor connected to the conductor connecting part and the second radiating element. The second radiating element, the first radiating element, and the third radiating element that are disconnected from the ground conductor by switching the first, second, and third switching elements. A low-frequency antenna operation performed by the radiation element being electrically coupled via the first and second switch elements; the first radiation element; the third radiation element; and the fourth radiation. It is also characterized in that it is configured to switch between high frequency side antenna operation performed by the element being electrically coupled via the first and second switch elements.

  In the present invention, according to the configuration having the first, second and third radiating elements formed by strip-shaped or linear electrodes, the other end of the first radiating element and the other end of the second radiating element By switching the switch elements connected to the first side and the one end side of the third radiating element, the antenna operations on the low frequency side and the high frequency side can be switched. That is, by switching the switch element, the first radiating element and the third radiating element are electrically coupled via the switch element, and the antenna operation on the low frequency side is performed. It is possible to switch between high-frequency antenna operation performed by electrically coupling the radiating element to the radiating element via the switch element.

  In this way, the third radiating element that is combined with the first radiating element when operating the antenna on the low frequency side to form a part of the feeding element is coupled to the second radiating element when performing the antenna operation on the high frequency side. By making it function as a parasitic element, a sufficient antenna length can be obtained even in a small space compared to a configuration in which a feeding element and a parasitic element are separately formed and operated at the time of high-frequency and low-frequency antenna operations. Cheap.

  When performing antenna operation on the low frequency side, the first radiating element whose one end is connected to the feeding point is coupled to the third radiating element, and this coupled configuration is operated as the feeding element. It is possible to obtain a sufficiently long antenna size by forming the element so that the allowable antenna space can be used as much as possible. Therefore, high antenna efficiency can be obtained in the antenna operation on the low frequency side.

  On the other hand, when performing antenna operation on the high frequency side, a relatively high antenna efficiency can be obtained even if the antenna size is shorter than that on the low frequency side. Efficiency can be obtained. When performing antenna operation on the high frequency side, one end of the second radiating element is connected to the ground conductor, and the second radiating element and the third radiating element are coupled to form a parasitic element. By capacitively coupling the feed element with the first radiating element functioning as the feed element, a double resonance can be achieved, and a wide band can be realized.

  Further, a conductor connecting switch element for switching presence / absence of connection between a ground conductor connected to the conductor connecting portion and the second radiating element, and a low frequency excitation frequency at the conductor connecting portion of the second radiating element By providing any one of the parallel resonance circuit which performs parallel resonance in the second antenna, it is possible to prevent the second radiating element from degrading the radiation characteristics of the antenna operation due to the antenna operation on the low frequency side. In particular, the configuration provided with the parallel resonance circuit can provide the same effect by installing the circuit without providing a function for operating the switch element and operating it appropriately as in the configuration provided with the conductor connecting switch element. Therefore, the configuration can be simplified.

  Further, in the present invention, according to the configuration having the first, second, third, and fourth radiating elements formed by strip-shaped or linear electrodes, the other end side of the second radiating element is divided into two. By branching and switching the first and second switch elements provided at each branch end and the third switch element provided on one end side (conductor connection portion side) of the second radiating element, the low frequency side and the high frequency side are switched. The antenna operation on the side can be switched. Further, the second radiating element, which is combined with the first radiating element when the low frequency side antenna is operated to form a part of the feeding element, functions as a parasitic element when the high frequency side antenna is operated, thereby Similar to the present invention having the first, second and third radiating elements, a sufficient antenna length can be obtained even in a small space.

  When performing antenna operation on the low frequency side, disconnect the second radiating element from the ground conductor, disconnect the first radiating element with one end connected to the feed point, and the third radiating element with the other end open. The radiating element is combined with the second radiating element branched at the other end, but the second radiating element having the branching portion is likely to have a long length. Therefore, by connecting the second radiating element and the first and third radiating elements, it becomes easy to form an antenna size with such a length that the power feeding element can be used to the maximum extent possible. High antenna efficiency can be obtained in the antenna operation on the frequency side.

  On the other hand, when performing antenna operation on the high frequency side, relatively high antenna efficiency can be obtained even if the antenna size is shorter than on the low frequency side, so that sufficient antenna efficiency can be obtained even if the second radiating element is disconnected. Can do. When performing antenna operation on the high frequency side, the first, third, and fourth radiating elements are combined to form a coupling element, and the second radiating element is connected to a grounding conductor to form a parasitic element. To do. Then, this parasitic element (second radiating element) can be capacitively coupled to the feeding element (coupled configuration of the first, third, and fourth radiating elements) to achieve multiple resonances, thereby enabling a wide band. Can do.

  Also, by providing at least one reactance element in at least one radiating element, even if it is difficult to adjust the operating frequency of the antenna operation only by setting the length of the radiating element, the reactance element is arranged. The operating frequency can be adjusted to a desired frequency in at least one of the antenna operations on the low frequency side and the high frequency side according to the number and arrangement of the antennas.

  Furthermore, a plurality of reactance elements corresponding to mutually different frequencies are provided in parallel at at least one of the connection portions between the radiation element and the switch element, and the switch element is selectively connected to any of the reactance elements. The frequency range of antenna operation can be set to a wider frequency range.

  In addition, by providing a reactance circuit in the first radiating element feeding connection that makes the low-frequency antenna operation double resonance, the antenna operation on the low frequency side is double-resonated to increase the bandwidth of the antenna operation. Can be planned.

  Further, by forming the radiating element and the switch element on a base or film having a dielectric constant or an inductive factor, the radiating element is formed by connecting the radiating element to the feeding point and the radiating element is formed by connecting to the ground conductor. Necessary coupling between the parasitic elements can be easily generated.

It is typical explanatory drawing for demonstrating the antenna structure of 1st Example. It is typical explanatory drawing for demonstrating the antenna structure of 2nd Example. It is typical explanatory drawing for demonstrating the antenna structure of 3rd Example. It is typical explanatory drawing for demonstrating the antenna structure of 4th Example. It is typical explanatory drawing for demonstrating the antenna structure of 5th Example. It is typical explanatory drawing for demonstrating the antenna structure of 6th Example. It is typical explanatory drawing for demonstrating the antenna structure of another Example. It is explanatory drawing which shows the example of the conventional multiband antenna structure. It is explanatory drawing which shows another example of the conventional multiband antenna structure.

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

  FIG. 1A is a schematic plan view showing the configuration of the first embodiment of the antenna structure according to the present invention. As shown in the figure, the antenna structure of the first embodiment has first, second, and third radiating elements 1, 2, and 3 formed by strip-shaped electrodes. The second and third radiation electrodes 1, 2, 3 are disposed in the non-ground region Zp of the substrate 10. The substrate 10 is disposed, for example, in a casing of a mobile phone, and has a ground region Zg where a ground conductor (ground electrode) is formed and the non-ground region Zp where a ground conductor is not formed. ing.

  The first radiating element 1 has an L shape, and one end thereof forms a feeding connection portion 1 a connected to the feeding point 5. A reactance element 11 is interposed in the power supply connection portion 1a. The first radiating element 1 is extended from the power supply connection portion 1a to the corner of the substrate 10 along the side 20 of the substrate 10, bent at the corner, and the end of the substrate 10 (the end of the non-ground region Zp). ) Is extended to the center along the side 21. A switch element 7 is provided on the other end side of the first radiating element 1 via a reactance element 12.

  The second radiating element 2 is formed in a straight line, and one end of the second radiating element 2 forms a conductor connecting portion 2a connected to the ground conductor (on the ground region Zg side). The conductor connection portion 2 a is provided with a conductor connection switch element 6 via a reactance element 13. The second radiating element 2 is provided at the center of the non-ground region Zp of the substrate 10 and is formed in parallel to the side 20 of the substrate 10 in a direction crossing the non-ground region Zp in the vertical direction of FIG. ing. The other end side of the second radiating element 2 is connected to the switch element 7. One end side of the third radiating element 3 is connected to the switch element 7 and is formed linearly along the side 21 of the substrate 10. The other end side of the third radiation electrode 3 forms an open end 3a.

  FIGS. 1B and 1C are schematic plan views for explaining the radiating element connection state during the antenna operation of the first embodiment. In this embodiment, by switching the switch element 7, As shown in FIG. 1 (b), the antenna operation on the low frequency side performed by the first radiating element 1 and the third radiating element 3 being electrically coupled via the switch element 7, and FIG. ), The second radiating element 2 and the third radiating element 3 are configured to switch the antenna operation on the high frequency side which is electrically coupled via the switch element 7. .

  The conductor connecting switch element 6 is a switch for switching the connection between the second radiating element 2 and the ground conductor. When performing the antenna operation on the low frequency side, the conductor connecting switch element 6 is as shown by a solid line in FIG. . By disconnecting the conductor connecting switch element 6 from the second radiating element 2 in this manner, the second radiating element 2 is disconnected from the ground conductor as shown in FIG. On the other hand, when the antenna operation on the high frequency side is performed, as shown in the broken line in FIG. 1A, the conductor connecting switch element 6 is connected to the second radiating element 2 as shown in FIG. In addition, the second radiating element 2 is connected to the ground conductor. As a result, the coupling configuration of the second radiating element 2 and the third radiating element 3 becomes a parasitic element, and this parasitic element is capacitively coupled to the first radiating element 1 that functions as a feeding element.

Note that the total length of the first radiating element 1 and the third radiating element 3 is a length that resonates at λ _L / 4 in the antenna operation of the wavelength λ _L on the low frequency side, and the first and third feed element resonates at the frequency of the wavelength lambda _L of the radiating elements 1 are formed by electrically coupled. The first length of the radiating element 1 is the length which resonates at lambda _{H1 / 4} in the antenna operation of the wavelength lambda _H1 of the high-frequency side, the first radiating element 1 functioning as a power feeding element wavelength lambda _H1 Resonates at. The total length of the second radiating element 2 and the third radiating element 3 is a length that resonates at λ _H2 / 4 in the antenna operation of the wavelength λ _H2 , and the second and third radiating elements 2 , 3 are electrically coupled to each other and the parasitic element is resonated at the wavelength λ _H2 . As described above, double resonance occurs at the frequencies λ _H1 and λ _H2 .

  Further, in this embodiment, the frequency at the time of operating each antenna is finely adjusted by reactance elements 11-13. The frequency at the time of antenna operation on the low frequency side is adjusted by the reactance elements 11, 12, and the resonance frequency when double resonance occurs between the feeding element and the parasitic element at the time of antenna operation on the high frequency side is And adjusted by the reactance element 13 on the parasitic element side.

  FIG. 2A is a schematic plan view showing the configuration of a second embodiment of the antenna structure according to the present invention. In addition, in the description of the second embodiment, including the description of the second embodiment, the same reference numerals are given to the same name portions as those in the first embodiment, and the duplicate description is omitted or simplified.

  The basic structure of the second embodiment is the same as that of the first embodiment. The second embodiment is different from the first embodiment in that the shapes of the first, second, and third radiating elements 1, 2, and 3 are the same. The length is different. That is, in the second embodiment, the first radiating element 1 has an L shape, but extends from the power supply side connection portion 1a along the side 20 of the substrate 10 to the middle portion of the non-ground region Zp. Thereafter, it is formed in parallel with the side 21 of the substrate 10 so as to cross the non-ground region Zp in the lateral direction of FIG. The other end side of the first radiating element 1 extends to the vicinity of the side 22 (side opposite to the side 20) of the substrate 10 and is connected to the switch element 7.

  The second radiating element 2 extends from the conductor connecting portion 2 a along the side 22 of the substrate 10 to the middle portion of the non-ground region Zp, and the other end side is connected to the switch element 7. The reactance element 13 is provided at the center of the second radiating element 2. One end side of the third radiating element 3 is formed in the middle of the non-ground region Zp on the side 22 side of the substrate 10, and is connected to the switch element 7. The third radiating element 3 is formed along the side 22 to the corner of the non-ground region Zp, then bent, formed along the side 21 of the substrate 10 to the vicinity of the side 20, and along the side 22. A reactance element 14 is interposed in the formed region.

FIGS. 2B and 2C are schematic plan views for explaining the radiating element connection state during the antenna operation of the second embodiment. In the second embodiment, the switch element 7 is switched. As shown in FIG. 2B, the antenna operation on the low frequency side performed by the first radiating element 1 and the third radiating element 3 being electrically coupled via the switch element 7, and FIG. As shown in c), the second radiating element 2 and the third radiating element 3 are switched to the high frequency side antenna operation performed by being electrically coupled via the switch element 7. In the second embodiment, the relationship between the lengths of the first, second, and third radiating elements 1, 2, and 3 and the antenna operating wavelengths λ _L , λ _H1 , and λ _H2 is the same as in the first embodiment. It is.

  In addition, the frequency at the time of antenna operation on the low frequency side is adjusted by the reactance elements 11 and 14, and the resonance frequency when double resonance is caused between the feeding element and the parasitic element at the time of antenna operation at the high frequency side is fed by the reactance element 11. It is adjusted on the element side and adjusted on the parasitic element side by the reactance elements 13 and 14.

  FIG. 3A is a schematic plan view showing the configuration of a third embodiment of the antenna structure according to the present invention. The third embodiment has a fourth radiating element 4 in addition to the first, second and third radiating elements 1, 2, 3. The first radiating element 1 has an L-shape, and is extended from the power supply side connecting portion 1a along the side 20 of the substrate 10 to the middle portion of the non-ground region Zp, as in the second embodiment. These are formed in parallel with the side 21 of the substrate 10 up to the center of the non-ground region Zp. A first switch element 8 is provided on the other end side of the first radiating element 1.

  The second radiating element 2 has a conductor connecting portion 2a connected at one end to a ground conductor, and a reactance element 13 and a third switch element 23 are interposed at one end thereof. The third switch element 23 is a switch for switching presence / absence of connection between the second radiating element 2 and the ground conductor. The second radiating element 2 is extended along the side 22 from one end side toward the corner of the substrate 10 and branched into two at a branch portion formed in the middle of the non-ground region Zp. . Reactance elements 18 and 19 are interposed in the vicinity of the branch portion.

  One side where the second radiating element 2 is branched is formed in parallel with the side 21 of the substrate 10 and crosses the non-ground region Zp in the lateral direction of FIG. 3A in the center of the non-ground region Zp. The end portion (branch end) is connected to the first switch element 8. The other side of the second radiating element 2 that is branched at the branching portion extends to the corner of the substrate 10 along the side 22 of the substrate 21, and is bent at the corner to bend the side 21 of the substrate 10. And is extended to the center of the side 21. The end (branch end) is connected to the second switch element 9.

  One end side of the third radiating element 3 is connected to the second switch element 9, is formed in a straight line along the side 21 of the substrate 10, and the other end side is an open end 3a. The fourth radiating element 4 is formed in a straight line in the direction crossing the non-ground area Zp in the vertical direction of FIG. 3A at the center of the non-ground area Zp, and one end side is connected to the first switch element 8. The other end side is connected to the second switch element 9. A reactance element 15 is interposed in the center of the fourth radiating element 4.

  FIGS. 3B and 3C are schematic plan views for explaining the radiating element connection state during the antenna operation of the third embodiment. In the third embodiment, the first and second switches are shown. By switching the elements 8 and 9, as shown in FIG. 3 (b), the first radiating element 1, the second radiating element 2, and the third radiating element 3 are switched between the first and second switching elements 8. , 9 and the low-frequency side antenna operation that is electrically coupled, and as shown in FIG. 3C, the first radiating element 1, the third radiating element 3, and the fourth radiating element 4 Is configured to switch between high-frequency antenna operation performed by being electrically coupled via the first and second switch elements 8 and 9.

  When performing the antenna operation on the low frequency side, as shown in the solid line of FIG. 3A, the third switch element 23 is separated from the second radiating element 2 as shown in FIG. In addition, the coupling configuration of the first radiating element 1, the second radiating element 2, and the third radiating element 3 is not connected to the ground conductor. On the other hand, when the antenna operation on the high frequency side is performed, the third switch element 23 is connected to the second radiating element 2 as shown in the broken line in FIG. In addition, the second radiating element 2 is connected to the ground conductor. Thus, the second radiating element 2 is a parasitic element, and the parasitic element (second radiating element 2) is the first radiating element 1, the third radiating element 3, and the fourth radiating element 4. And capacitive coupling with the coupling configuration (feeding element).

In the third embodiment, the total length of the first radiating element 1, the second radiating element 2, and the third radiating element 3 resonates at λ _L / 4 in the antenna operation of the wavelength λ _L on the low frequency side. the length of the feeding device first and second and third radiating elements 1, 2 and 3 are formed by electrically coupling to resonate at the frequency of the wavelength lambda _L. Further, the total length of the first radiating element 1, the third radiating element 3, and the fourth radiating element 4 is a length that resonates at λ _H1 / 4 in the antenna operation of the wavelength λ _H1 on the high frequency side. The feed element formed by electrically coupling the first, third and fourth radiating elements 1, 3 and 4 resonates at the wavelength λ _H1 . The length from the conductor connection portion 2a of the second radiating element 2 to each branch end is a length that resonates at λ _H2 / 4 and λ _H3 / 4 in the antenna operation of the wavelengths λ _H2 and λ _H3 . The second radiating element 2 functioning as a parasitic element resonates at wavelengths λ _H2 and λ _H3 .

  In the third embodiment, the frequency when the antenna on the low frequency side is operated is adjusted by the reactance elements 11, 13, 18, and 19, and when the high frequency side antenna is operated, a double resonance occurs between the feeding element and the parasitic element. The resonance frequency is adjusted on the feeding element side by the reactance elements 11 and 15, and is adjusted on the parasitic element side by the reactance elements 13, 18, and 19.

  In the first and second embodiments, when the antenna operation on the low frequency side is performed, the combined configuration of the first radiating element 1 and the third radiating element 3 functions as a feeding element, During antenna operation, the open end of the feed element forms the open end 3a of the third radiating element 3, and thus is formed at the corner of the non-ground region Zp. On the other hand, when the antenna operation on the high frequency side is performed, the first radiating element 1 functions as a feeding element, so that the open end of the feeding element at the time of the antenna operation on the high frequency side is the other end of the first radiating element 1. It becomes a connection part with the switch element 7 on the side, and becomes an end center part of the non-ground region Zp of the substrate 10.

  On the other hand, in the third embodiment, when the antenna operation on the low frequency side is performed, the coupling configuration of the first, second and third radiating elements 1, 2 and 3 functions as a feeding element, When performing the antenna operation, the coupling configuration of the first, third, and fourth radiating elements 1, 3, and 4 is a configuration that functions as a feeding element, and in any operation, a configuration that functions as a feeding element. The open end is the open end 3 a of the third radiating element 3. Since the open end 3a is formed at the corner of the non-ground region Zp farthest from the ground region Zg of the substrate 10, in the third embodiment, the influence of the ground (grounding conductor) is caused during the operation of the antenna on the high frequency side. It is harder to receive than the first and second embodiments, so that the radiation efficiency can be further improved.

  FIG. 4A is a schematic plan view showing the configuration of the fourth embodiment of the antenna structure according to the present invention. The fourth embodiment has the same basic configuration as the first embodiment, and the fourth embodiment is different from the first embodiment in that the conductor connecting switch element 2a of the second radiating element 2 is connected to the conductor connecting switch element. Instead of 6, a parallel resonance circuit 24 that resonates in parallel at the excitation frequency on the low frequency side is provided. A circuit diagram of the parallel resonant circuit 24 is shown in FIG.

  FIG. 5A is a schematic plan view showing the configuration of the fifth embodiment of the antenna structure according to the present invention. The fifth embodiment has the same basic configuration as the first embodiment, and the fifth embodiment is different from the first embodiment in that the connection between the first radiating element 1 and the switch element 7 is shown in FIG. As shown in (b), a circuit unit 25 is provided in which a plurality of reactance elements L1 and L2 corresponding to different frequencies are provided in parallel, and the switch element 7 having the configuration shown in FIG. , L2 is configured to be selectively connected.

  FIG. 6A is a schematic plan view showing the configuration of the sixth embodiment of the antenna structure according to the present invention. The basic configuration of the sixth embodiment is the same as that of the first embodiment, and the sixth embodiment is different from the first embodiment in that the low frequency side antenna is connected to the feeding connection portion 1a of the first radiating element 1. This is that a reactance circuit 26 is provided to make the operation a double resonance operation. FIG. 6B shows the configuration of the reactance circuit 26.

  In addition, this invention is not limited to the said Example, Various embodiment can be taken. For example, in the first, second, fifth, and sixth embodiments, when the characteristic variation due to the second radiating element 2 can be ignored during the operation of the antenna on the low frequency side, the conductor connecting switch element 6 is omitted. You can also.

  The radiating elements 1 to 4 and the switch elements 7 to 9 may be formed directly in the non-ground region Zp of the substrate 10, but may be formed on a dielectric or a substrate or a film having an inductivity so as to be non-grounded. You may arrange | position to the area | region Zp.

  Further, in each of the above embodiments, any one of the reactance elements 11 to 15, 18, and 19 is provided at an appropriate position. However, the arrangement of the reactance elements is not limited to each of the above embodiments and may be various. By providing at least one reactance element in at least one radiating element, the operating frequency is desired as required in at least one of the low frequency side and high frequency side antenna operations. The frequency can be adjusted.

  For example, as shown in FIG. 7A, in the first embodiment, a reactance element 16 may also be provided in the third radiating element 3. In this case, the arrangement of the reactance element 16 adjusts the frequency when the antenna on the low frequency side operates and the resonance frequency on the side of the parasitic element when the power feeding element and the parasitic element perform double resonance when the antenna on the high frequency side operates. Is done. Further, as shown in FIG. 7B, in the second embodiment, a reactance element 17 may be provided on the connection end side of the first radiating element 1 with the switch element 7. The frequency at the time of antenna operation on the low frequency side is adjusted by the arrangement of the reactance element 17.

  In addition, the arrangement position of the reactance element interposed in the radiating element is not particularly limited and is appropriately set, but when the reactance element is provided at a position close to the feeding point 5 or the ground conductor side, Since the amount of current on the radiating element is large, the frequency can be changed greatly with a small reactance value. However, the antenna efficiency deteriorates due to the resistance component of the reactance element. Therefore, it is desirable to provide a reactance element having an appropriate value at an appropriate position in consideration of the balance between frequency adjustment efficiency and antenna efficiency.

  Further, in each of the above embodiments, the radiating element is formed by a strip-shaped electrode, but the radiating element may be formed by a linear electrode. The length and shape are appropriately set in consideration of the operating frequency and the like.

  Furthermore, the aspect of the substrate 10 on which the antenna structure of the present invention is arranged is not particularly limited, and is appropriately set. In the appropriate substrate 10 having the ground region Zg and the non-ground region Zp, By arranging the antenna structure of the present invention in the non-ground region Zp, the excellent effects as in the above embodiments can be obtained.

  The antenna structure of the present invention is small, has high antenna efficiency, and can operate with a plurality of frequencies, and thus can be applied as an antenna structure for a wireless device such as a portable telephone.

DESCRIPTION OF SYMBOLS 1 1st radiation element 2 2nd radiation element 3 3rd radiation element 4 4th radiation element 5 Feeding point 6 Conductor switch element 7 Switch element 8 First switch element 9 Second switch element 10 Substrate 11-17 Reactance element 24 Parallel resonant circuit 26 Reactance circuit

Claims (7)

  First, second, and second electrodes formed by strip-like or linear electrodes disposed in the non-ground region of the substrate having a ground region in which a ground conductor is formed and a non-ground region in which no ground conductor is formed. The first radiating element has a feeding connection portion whose one end side is connected to a feeding point, a switching element is provided on the other end side, and the second radiating element has one end side on the one end side. The other end of the third radiating element is connected to the switch element, and the other end of the third radiating element is an open end. , By switching the switching element, the first radiating element and the third radiating element are electrically coupled via the switch element, and the antenna operation on the low frequency side and the second radiating element Element and said third radiation element Antenna structure, wherein the bets has a configuration for switching between the high-frequency side of the antenna operation performed electrically coupled via the switching element.   The conductor connecting portion of the second radiating element includes a conductor connecting switch element for switching presence / absence of connection between the ground conductor connected to the conductor connecting portion and the second radiating element, and an excitation frequency on the low frequency side. 2. The antenna structure according to claim 1, wherein either one of a parallel resonance circuit that performs parallel resonance is provided.   First, second, and second electrodes formed by strip-like or linear electrodes disposed in the non-ground region of the substrate having a ground region in which a ground conductor is formed and a non-ground region in which no ground conductor is formed. The first radiating element has a power supply connecting portion connected at one end side to a power supply point, and the first switch element is provided at the other end side. One of the radiating elements is formed as a conductor connecting portion connected to the ground conductor, the other end is branched into two, one branch end is connected to the first switch element, and the other branch end is the second branch end. One end side of the third radiating element is connected to the second switch element, the other end side is an open end, and the fourth radiating element is one end side of the first radiating element. Connected to the switch element and the other end is connected to the second switch element. In addition, the conductor connecting portion of the second radiating element is provided with a third switch element for switching the connection between the ground conductor connected to the conductor connecting portion and the second radiating element. The second radiating element, the first radiating element, and the third radiating element, which are disconnected from the ground conductor by switching the first, second, and third switching elements, The antenna operation on the low frequency side that is electrically coupled via the first and second switch elements, the first radiating element, the third radiating element, and the fourth radiating element are An antenna structure characterized in that it is configured to switch between high-frequency side antenna operations performed by electrical coupling through first and second switch elements.   The antenna structure according to claim 1, 2 or 3, wherein at least one radiating element is provided with one or more reactance elements.   A structure in which a plurality of reactance elements corresponding to different frequencies are provided in parallel in at least one of the connection portions of the radiation element and the switch element, and the switch element is selectively connected to any one of the reactance elements. The antenna structure according to any one of claims 1 to 4, wherein the antenna structure is configured as described above.   The antenna structure according to any one of claims 1 to 5, wherein a reactance circuit for performing double resonance of an antenna operation on a low frequency side is provided at a feeding connection portion of the first radiating element. .   7. The antenna structure according to claim 1, wherein the radiating element and the switching element are formed on a base or a film having a dielectric constant or an inductive factor.

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