JP5831754B2 - Antenna device - Google Patents

Description

  The present invention relates to an antenna device capable of making multiple resonances.

2. Description of the Related Art Conventionally, in communication equipment, an antenna device using a radiation electrode and a dielectric block, an antenna device using a switch, and a control voltage source has been proposed to make the resonance frequency of the antenna double resonant.
For example, as a conventional technique using a dielectric block, Patent Document 1 proposes a composite antenna that achieves high efficiency by forming a radiation electrode on a resin molded body and further integrating the dielectric block with an adhesive. .

  Further, as a conventional technique using a switch and a control voltage source, in Patent Document 2, a first radiation electrode, a second radiation electrode, a middle portion of the first radiation electrode, and a base end of the second radiation electrode are disclosed. An antenna device has been proposed that includes a switch interposed between the first radiation electrode and the second radiation electrode to electrically connect or disconnect the first radiation electrode.

JP 2010-81000 A JP 2010-166287 A

However, the following problems remain in the above-described conventional technology.
That is, in the technique using the dielectric block as described in Patent Document 1, a dielectric block that excites the radiation electrode is used, and it is necessary to design the dielectric block, the radiation electrode pattern, etc. for each device. Depending on design conditions, antenna performance may be degraded, and unstable elements may increase. In addition, since the radiation electrode is formed on the surface of the resin molding, it is necessary to design the radiation electrode pattern on the resin molding. Depending on the communication equipment to be mounted and its application, the antenna design and mold design This is necessary and causes a significant increase in cost. Furthermore, since the dielectric block and the molded resin are integrated with an adhesive, the antenna performance may be degraded or unstable depending on the adhesive conditions (adhesive thickness, adhesive area, etc.) in addition to the adhesive Q value. There is a disadvantage that the number of elements increases.
In addition, in the case of an antenna device using a switch and a control voltage source as described in Patent Document 2, a configuration of a control voltage source, a reactance circuit, and the like are required to switch the resonance frequency with the switch. However, there is a problem in that each device is complicated, there is no degree of freedom in design, and easy antenna adjustment is difficult.
Therefore, the present inventors have proposed an antenna in which a ground plane and a plurality of antenna elements are respectively formed by patterning metal foil on an insulating substrate body as an antenna device that can be double-resonant and can be reduced in size and thickness. We have been diligently researching the device, but forming a plurality of antenna elements that extend separately from the feeding point has the disadvantage that it is difficult to flow high-frequency current from the feeding point through each antenna element in a balanced manner. . In addition, there has been a problem that the antenna performance deteriorates due to the influence of peripheral components that have become closer to each other due to the reduction in size and thickness.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an antenna device capable of effectively flowing a high-frequency current through a plurality of antenna elements and suppressing the influence of peripheral components. And

  The present invention employs the following configuration in order to solve the above problems. That is, the antenna device according to the first invention includes an insulating substrate body, a ground surface patterned with a metal foil on the substrate body, and a plurality of antenna elements, and the plurality of antenna elements are A common feeding point is provided at the base end in the vicinity of the ground plane, and these are divided into one of a first base end part and a second base end part extending in two different directions from the power feeding point. A first ground connection portion having a proximal end connected to the ground surface and a distal end connected to the middle of the first proximal end portion, and a proximal end connected to the first ground connection portion. A connection between the first ground connection portion of the first base end portion and a second ground connection portion that is connected to the ground plane at a distance from the position and whose tip is connected in the middle of the second base end portion Tip than part And a connection pattern extending by connecting the tip end side of the second base end portion with respect to the connection portion of the second ground connection portion, and in the vicinity of the feeding point, the connection pattern and the first base An annular opening pattern portion is formed between the end portion and the second base end portion.

  In this antenna device, an annular opening pattern portion is formed between the connection pattern, the first base end portion, and the second base end portion in the vicinity of the feeding point. It is possible to reduce an adverse effect from the capacitive component generated between the parts and to achieve high performance for each element. That is, the opening pattern portion allows a high-frequency current flow from the feeding point to each element on the first base end side and the second base end side to flow effectively in a balanced manner.

An antenna device according to a second invention is the antenna device according to the first invention, wherein at least one of the plurality of antenna elements is spaced apart from the opening pattern portion so that stray capacitance can be generated therebetween. It is characterized by extending.
That is, in this antenna device, since at least one of the plurality of antenna elements extends in a state of being opposed to the opening pattern portion so that stray capacitance can be generated therebetween, the opening pattern portion Stray capacitance can be generated between the antenna element and the opposing antenna element, and impedance adjustment at the resonance frequency of the antenna element can be performed.

An antenna device according to a third invention is the antenna device according to the first or second invention, wherein at least one of the plurality of antenna elements extends with a passive element in the middle, and at least one of the plurality of antenna elements is The antenna elements of the dielectric antenna are extended so that the plurality of antenna elements can generate stray capacitance between adjacent antenna elements and stray capacitance between the ground planes, respectively. The antenna element and the ground plane extend at a distance from each other.
That is, in this antenna device, a plurality of antenna elements can generate stray capacitance between adjacent antenna elements and stray capacitance between the ground plane, respectively, with respect to the adjacent antenna element and the ground plane. Thus, multiple resonance can be achieved by effectively using the antenna element of the loading element that does not self-resonate at a desired resonance frequency and the stray capacitance between the elements. Further, by selecting antenna elements and passive elements (changing constants, etc.), it is possible to flexibly adjust each resonance frequency, and it is possible to obtain an antenna device that can resonate according to design conditions. In this way, each resonance frequency can be flexibly adjusted with one antenna device due to the antenna configuration, so that the resonance frequency can be switched, and the adjustment location by the passive element etc. can be changed according to the application and equipment. Yes. The bandwidth can be adjusted by setting the length and width of each element and each stray capacitance.
In addition, it can be designed in the plane of the substrate body, and can be made thinner than when using a conventional dielectric block or resin molded body, and also by selecting an antenna element that is a dielectric antenna. , Downsizing and high performance are possible. Further, there is no need for costs due to molds, design changes, etc., and low costs can be realized.

The present invention has the following effects.
That is, according to the antenna device of the present invention, the annular opening pattern portion is formed between the connection pattern, the first base end portion, and the second base end portion in the vicinity of the feeding point. The adverse effect from the capacitive component generated between the peripheral components can be reduced by the capacitive component generated at the same time, and the performance of each element can be improved.
In particular, it is effective when the distance from the peripheral parts becomes short with the miniaturization and thinning, and it is possible to achieve both miniaturization and high performance.

In one Embodiment of the antenna device which concerns on this invention, it is a wiring diagram which shows an antenna device. In this embodiment, it is a wiring diagram which shows the stray capacitance produced with an antenna apparatus. In this embodiment, it is the top view and back view which show the board | substrate for antenna devices. In this embodiment, it is a top view which shows an antenna apparatus. In this embodiment, they are a perspective view (a), a plan view (b), a front view (c), and a bottom view (d) showing an antenna element. In this embodiment, it is explanatory drawing for demonstrating the function of an opening pattern part. 5 is a graph showing VSWR characteristics (voltage standing wave ratio) at four resonances in an example of an antenna device according to the present invention. In the Example which concerns on this invention, it is a graph which shows the radiation pattern of 920MHz band, 1400MHz band, and 1920MHz band.

  Hereinafter, an embodiment of an antenna device according to the present invention will be described with reference to FIGS.

As shown in FIGS. 1 to 4, the antenna device 10 according to the present embodiment includes an insulating substrate body 2, a ground surface GND and a plurality of ground surfaces GND each formed by patterning a metal foil such as a copper foil on the substrate body 2. Antenna elements EL1 to EL4 are provided.
The plurality of antenna elements EL <b> 1 to EL <b> 4 are provided with a common feeding point FP at the base end in the vicinity of the ground plane GND, and a first extending portion extending in two different directions from the feeding point FP ( The first base end portion E1 and the sixth extension portion (second base end portion) E6 are divided into and connected to these.

That is, the antenna device 10 includes an antenna device substrate 1, and the antenna device substrate 1 is formed by patterning the substrate body 2 and the substrate body 2 with a metal foil such as a copper foil. , Second element EL2, third element EL3, fourth element EL4, and ground plane GND.
A mounting area for RF circuit components and the like is provided on the ground plane GND. The ground surface GND is formed not only on the front surface of the substrate body 2 but also on the back surface in the same pattern corresponding to the front surface.

The first element EL1 is provided with a feeding point FP at the base end in the vicinity of the ground plane GND, and a first connection portion C1 to which the first passive element P1 can be connected midway and an antenna element AT of the dielectric antenna. Are extended in this order. In the present embodiment, as shown in FIGS. 3 and 4, the first passive element P1 is mounted on each of the two first connection portions C1, and the two first passive elements P1 are connected in series.
The second element EL2 includes a second connection portion C2 whose base end is connected between the feeding point FP of the first element EL1 and the first connection portion C1, and to which the second passive element P2 can be connected. It is extended.

  The third element EL3 has a power supply point FP connected to the base end and has a third connection portion C3 to which the third passive element P3 can be connected midway. In this embodiment, as shown in FIGS. 3 and 4, the third passive element P3 is mounted on each of the two third connection portions C3, and the two third passive elements P3 are connected in series.

  The fourth element EL4 has a base end connected between the feeding point FP of the third element EL3 and the third connection portion C3, and has a fourth connection portion C4 to which the fourth passive element P4 can be connected midway. It is extended. In this embodiment, as shown in FIGS. 3 and 4, the fourth passive element P4 is mounted on each of the two fourth connection portions C4, and the two fourth passive elements P4 are connected in series. The first passive element P1, the third passive element P3, and the fourth passive element P4 each use a combination of two passive elements. However, two passive elements having the same characteristics may be used and different characteristics may be used. Two passive elements may be used. Further, instead of a combination of two passive elements, one passive element or a combination of three or more passive elements may be used.

  The first element EL1 extends in one direction along the ground plane GND in a direction extending away from the ground plane GND from the front end of the first extension E1 extending from the feeding point FP. The second extending portion E2 is connected to the antenna element AT extending in the direction along the ground plane GND from the tip of the second extending portion E2 via the first connecting portion C1. And a third extending portion E3. Here, the direction along the ground plane GND is the direction along the end side of the opposing ground plane GND.

The first extending portion E1 extends from the feeding point FP in one direction along the ground plane GND, then extends in a direction away from the ground plane GND, and further extends in one direction along the ground plane GND. It extends in one direction along the ground surface GND as a whole while bending in a crank shape.
The first element EL1 includes an eleventh extending portion E11 extending from the tip of the third extending portion E3 toward the ground surface GND, and a first element extending from the tip of the eleventh extending portion E11 along the ground surface GND. And a twelfth extending portion E12 extending toward the extending portion E1. That is, the tip end side of the first element EL1 is folded back by the eleventh extending portion E11 and the twelfth extending portion E12. Note that the eleventh extending portion E11 has a wide rectangular shape.

The second element EL2 includes a fourth extending portion E4 extending in the same direction as the second extending portion E2 from the distal end of the second extending portion E2 via the second connecting portion C2, and the fourth extending portion E2. A fifth extending portion E5 extending in the direction along the third extending portion E3 from the tip of the existing portion E4 toward the antenna element AT.
Further, the base end side of the fifth extending portion E5 from the portion facing the antenna element AT is a wide portion E5a formed wider than the tip end side.

The third element EL3 includes a sixth extending portion E6 extending from the feeding point FP in the other direction along the ground surface GND, and a third extending in a direction away from the ground surface GND from the tip of the sixth extending portion E6. A seventh extension E7 extending through the connection portion C3, and an eighth extension extending in the direction along the ground plane GND from the tip of the seventh extension E7 toward the fourth extension E4 And E8. The sixth extending portion E6 extends from the feeding point FP to the other side in the direction along the ground plane GND, then extends in a direction away from the ground plane GND, and further to the other side in the direction along the ground plane GND. It extends in a crank shape and extends to the other side in the direction along the ground surface GND as a whole.
That is, the base end portions (the first extending portion E1 and the sixth extending portion E6) of the first element EL1 and the third element EL3 extend separately from each other in the opposite direction from the feeding point FP.

  The eighth extending portion E8 has a first back surface pattern portion R1 connected to the front surface side via the through hole H and patterned on the back surface of the substrate body 2, and the first back surface pattern portion R1 is connected to the ground. It is formed wider toward the surface GND. The first back surface pattern portion R1 is connected to the front surface side eighth extending portion E8 by a through hole H on the end portion side of the substrate body 2.

The fourth element EL4 includes a ninth extension portion E9 having a tip connected to the middle of the seventh extension portion E7 and extending in the same direction at a distance from the seventh extension portion E7. And a tenth extending portion E10 extending in a direction away from the seventh extending portion E7 from the tip of the ninth extending portion E9.
A thirteenth extending portion E13 extending in a direction away from the ground surface GND is connected to the proximal end side of the tenth extending portion E10.
The thirteenth extending portion E13 has a second back surface pattern portion R2 connected to the front surface side through the through hole H and patterned on the back surface of the substrate body 2, and the second back surface pattern portion R2 is connected to the ground surface. It is formed wider toward the surface GND. The second back surface pattern portion R2 is connected to the thirteenth extending portion E13 on the front surface side through a through hole H on the end portion side of the substrate body 2.

  In addition, the antenna device substrate 1 has a base end connected to the ground plane GND and a tip in the middle of the first extending portion (first base end) E1, that is, the second element EL2 of the first element EL1. The first ground connection part G1 connected to the base end side with respect to the connection part between the first ground connection part G1 and the base end is connected to the ground surface GND apart from the position where the first ground connection part G1 is connected, and the distal end is A second ground connection portion G2 connected in the middle of the sixth extension portion (second base end portion) E6, that is, closer to the base end side than the connection portion of the third element EL3 to the fourth element EL4, and the first extension Than the connection portion of the first ground connection portion G1 of the existing portion (first base end portion) E1 and the connection portion of the second ground connection portion G2 of the sixth extension portion (second base end portion) E6. Connection pattern L1 extending by connecting the tip side It is equipped with a.

  Further, in the vicinity of the feeding point FP, an annular opening pattern portion S1 is formed between the connection pattern L1, the first extending portion (first base end portion) E1, and the sixth extending portion (second base end portion) E6. Is formed. That is, a part of the first extending portion E1 and the sixth extending portion E6 bent in a crank shape and the connection pattern L1 form a substantially rectangular opening pattern portion S1 that is long along the ground plane GND. Yes.

  A fifth passive element P5, which is an impedance adjustment passive element, is connected to the first ground connection part G1, and a sixth passive element P6, which is an impedance adjustment passive element, is connected to the second ground connection part G2. It is connected. In the present embodiment, the ground plane GND and the first element EL1 are directly connected only by the fifth passive element P5, and the fifth passive element P5 itself functions as the first ground connection portion G1. Further, the ground plane GND and the third element EL3 are directly connected only by the sixth passive element P6, and the sixth passive element P6 itself functions as the second ground connection portion G2.

The substrate body 2 is a general printed circuit board, and in this embodiment, a printed circuit board body made of a rectangular glass epoxy resin or the like is employed. In addition, the dimension of the board | substrate body 2 of this embodiment is a longitudinal direction: 110 mm, a transversal direction: 52 mm, and thickness: 1.0 mm. The dimensions of the antenna region (including a part of the ground plane GND below the fourth element EL4) in the board body 2 are 11 mm in the longitudinal direction of the board body 2 and 35 mm in the short direction of the board body 2.
The feeding point FP is connected to a feeding point of a high-frequency circuit (not shown) through a feeding means such as a coaxial cable. This power supply means includes various connectors such as a coaxial cable, a connector such as a receptacle, a connection structure in which the contact has a leaf spring shape, a connection structure in which the contact has a pin probe shape or a pin shape, and a connection structure using a soldering land. The structure can be adopted.
For example, when a coaxial cable is employed as the power feeding means, the ground wire of the coaxial cable is connected to the base end side of the ground surface GND, and the core wire of the coaxial cable is connected to the feeding point FP.

The antenna element AT is a loading element that does not self-resonate at a desired resonance frequency, and is a chip antenna in which a conductor pattern 102 such as Ag is formed on the surface of a dielectric 101 such as ceramic as shown in FIG. is there. As the antenna element AT, elements having different lengths, widths, conductor patterns 102, and the like may be selected according to the setting of the resonance frequency or the like, or the same element may be selected. The dimensions of the antenna element AT of the present embodiment are a lateral width of 10.5 mm, a depth of 3.0 mm, and a height of 0.8 mm.
As the first passive element P1 to the sixth passive element P6, for example, an inductor, a capacitor, or a resistor is employed.

  In the antenna device substrate 1 of the present embodiment, each element from the first element EL1 to the fourth element EL4 can generate a stray capacitance between adjacent elements and a stray capacitance between the ground plane GND. In addition, it extends with an interval from an adjacent element and the ground plane GND.

  That is, as shown in FIG. 2, the stray capacitance Ca between the twelfth extending portion E12 and the ground plane GND, and between the antenna element AT (third extending portion E3) and the twelfth extending portion E12. The stray capacitance Cb, the stray capacitance Cc between the antenna element AT and the fifth extension portion E5, the stray capacitance Cf between the third extension portion E3 and the fifth extension portion E5, and the fifth extension The stray capacitance Cg between the portion E5 and the eighth extension portion E8, and the stray capacitance between the opening pattern portion S1 (the first extension portion E1 and the sixth extension portion E6) and the eighth extension portion E8. Ch, the stray capacitance Ci between the eighth extension portion E8 and the thirteenth extension portion E13, the stray capacitance Cj between the seventh extension portion E7 and the ninth extension portion E9, and the tenth extension A stray capacitance Ck between the existing portion E10 and the ground plane GND can be generated. Further, a capacitance component Cd due to the opening pattern portion S1 is also generated.

  As shown in FIG. 4, the antenna device 10 of the present embodiment includes the antenna device substrate 1, and the first passive element P1, the second passive element P2, the third passive element P3, and the fourth passive element P4 are The first connection unit C1, the second connection unit C2, the third connection unit C3, and the fourth connection unit C4 are connected to each other.

  Next, the resonance frequency in the antenna device 10 of the present embodiment will be described with reference to FIG.

In the antenna device 10 according to the present embodiment, as shown in FIG. 7, the first resonance frequency f1, the second resonance frequency f2, the third resonance frequency f3, and the fourth resonance frequency f4 are double-resonated. Is done.
The first resonance frequency f1 is in a low frequency band (for example, 920 MHz band) of the four resonance frequencies, and the antenna element AT and the first element EL1 (first extension portion E1, second extension). Part E2, eleventh extending part E11 and twelfth extending part E12).

The broadening of the bandwidth at the first resonance frequency f1 is determined by the length and width of the twelfth extending portion E12, the eleventh extending portion E11, and the third extending portion E3.
In addition, the impedance at the first resonance frequency f1 is determined by each of the stray capacitances Ca to Cd.
Furthermore, the final adjustment of the first resonance frequency f1 can be flexibly adjusted using the first passive element P1.

Therefore, the first resonance frequency f1 is adjusted mainly at a portion surrounded by a broken line A1 in FIG.
Thus, with respect to the first resonance frequency f1, the resonance frequency and bandwidth are determined by setting the length and width of the first element EL1, the first passive element P1, the antenna element AT, and the stray capacitances. And the impedance can be adjusted flexibly.

Next, the third resonance frequency f3 is determined by the lengths of the first extending portion E1, the second extending portion E2, the fourth extending portion E4, and the fifth extending portion.
The broadening of the bandwidth at the third resonance frequency f3 is determined by the lengths and widths of the first extending portion E1, the second extending portion E2, the fourth extending portion E4, and the fifth extending portion.
The impedance at the third resonance frequency f3 is determined by the stray capacitances Cd, Cc, Cf, Cg.
Furthermore, the final adjustment of the third resonance frequency f3 can be flexibly adjusted using the second passive element P2.

Therefore, the third resonance frequency f3 is adjusted mainly at a portion surrounded by a one-dot chain line A3 in FIG.
Thus, for the third resonance frequency f3, the length and width of the first extending portion E1, the second extending portion E2, and the second element EL2, the second passive element P2, and each of the stray capacitances described above are used. Therefore, the resonance frequency, bandwidth and impedance can be adjusted flexibly.

Next, the fourth resonance frequency f4 is determined by the lengths of the eighth extending portion E8 and the seventh extending portion E7.
The broadening of the bandwidth at the fourth resonance frequency f4 is determined by the length and width of the eighth extending portion E8 and the seventh extending portion E7.
The impedance at the fourth resonance frequency f4 is determined by the stray capacitances Cd, Cg, Ch, and Ci.
Further, the final adjustment of the fourth resonance frequency f4 can be flexibly adjusted using the third passive element P3.

Therefore, the fourth resonance frequency f4 is adjusted mainly at a portion surrounded by a two-dot chain line A4 in FIG.
Thus, for the fourth resonance frequency f4, the length and width of the third element EL3 (the seventh extending portion E7 and the eighth extending portion), the third passive element P3, and each of the stray capacitances described above Therefore, the resonance frequency, bandwidth and impedance can be adjusted flexibly.

Next, the second resonance frequency f2 is determined by the lengths of the seventh extending portion E7, the thirteenth extending portion E13, the tenth extending portion E10, and the ninth extending portion E9.
The broadening of the bandwidth at the second resonance frequency f2 is determined by the lengths and widths of the seventh extending portion E7, the thirteenth extending portion E13, the tenth extending portion E10, and the ninth extending portion E9.
The impedance at the second resonance frequency f2 is determined by the stray capacitances Cd, Ci, Cj, and Ck.
Furthermore, the final adjustment of the second resonance frequency f2 can be flexibly adjusted using the fourth passive element P4.

Therefore, the second resonance frequency f2 is adjusted mainly at a portion surrounded by a broken line A2 in FIG.
Thus, for the second resonance frequency f2, the length and width of the seventh extending portion E7, the thirteenth extending portion E13, the tenth extending portion E10, and the ninth extending portion E9, and the fourth passive frequency The resonant frequency, bandwidth and impedance can be flexibly adjusted by setting the element P4 and each of the stray capacitances.
In addition, final impedance adjustment can be flexibly performed using the fifth passive element P5 and the sixth passive element P6 which are passive elements for impedance adjustment with respect to each of the resonance frequencies.

Next, the effect of the opening pattern portion S1 will be described.
In the present embodiment, the opening pattern portion S1 is provided in the vicinity of the feeding point FP, but the opening pattern portion S1 can effectively flow a high-frequency current from the feeding point FP to the left and right elements.
That is, when there is no opening pattern portion S1, as shown in FIG. 6B, in the flow of the high-frequency current from the feeding point FP, the antenna element on the right side (the third element EL3 and the fourth element) The flow to EL4) is smooth, but the flow to the left side generates a capacitive component with the element from the feed point FP. Similarly, in the case of the wiring shown in FIG. 6C, the flow to the left side is smooth, but the flow to the right side generates a capacitance component with the element from the feeding point FP.

As a result, two antenna elements are provided in each of the left and right directions, the influences are different, and the performance is deteriorated.
Further, as shown in FIG. 6D, in the case of the pattern connected from the center without the opening pattern portion S1, the same capacitance component is generated in both the left and right, and the performance deterioration is remarkable.

  Furthermore, as shown in FIG. 6 (e), in the case of a pattern in which the opening pattern portion S1 is a wide pattern without opening, and the pattern has a large area connected from the center, the high-frequency current to each element is Although there is no problem, the performance is increased due to the large area due to the mounting of components around the antenna. In particular, along with the reduction in size and thickness, the distance from the peripheral components is also reduced, and the performance is significantly deteriorated.

  Therefore, as shown in FIG. 6A, by providing the opening pattern portion S1 as in the present invention, the adverse effect from the capacitance component generated between the peripheral components due to the capacitance component in the opening pattern portion S1 is reduced. In addition, a high-frequency current flowing through each antenna element can be efficiently flowed, so that both miniaturization and high performance can be realized.

Next, the first back pattern portion R1 and the second back pattern portion R2 will be described.
First, in the first back surface pattern portion R1, stray capacitance is generated on the front surface with respect to the sixth extending portion E6 and the opening pattern portion S1.
When designing the first back surface pattern portion R1, stray capacitance is generated in the sixth extending portion E6. Therefore, the extending direction of the sixth extending portion E6 is effective depending on the thickness of the substrate body 2. In some cases, it may become impossible to use and interfere with the sixth extending portion E6.

  On the other hand, in the direction toward the opening pattern portion S1, the impedance is lower than that of the sixth extending portion E6, and the influence of interference is small due to the capacitance component on the opening pattern portion S1 side. Therefore, it is effective to design the first back surface pattern portion R1 so that the width of the tenth extending portion E10 is the maximum width and extends from the end side of the substrate body 2 in the extending direction of the sixth extending portion E6.

  Further, in the second back surface pattern portion R2, stray capacitance occurs between the tenth extending portions E10 and between the ground surfaces GND due to the pattern arrangement with the twelfth extending portions E12 in the thirteenth extending portion E13. . Therefore, the second back surface pattern portion R2, in the same way as the first back surface pattern portion R1, maximizes the width of the thirteenth extending portion E13 and is directed from the end side of the substrate body 2 toward the twelfth extending portion E12. A design that extends to the top is effective.

Next, the tenth extending portion E10 and the thirteenth extending portion E13 will be described.
The thirteenth extending portion E13 has a pattern arrangement orthogonal to the tenth extending portion E10. When the thirteenth extending portion E13 is arranged in a pattern only in the horizontal direction (the extending direction of the tenth extending portion E10), the eighth extending portion E8 is considered in consideration of the stray capacitance with the ground plane GND. The degree of freedom in design is reduced, such as the need to design stray capacitance between the two. For this reason, further miniaturization becomes difficult.

  Therefore, the tenth extending portion E10 that uses the stray capacitance between the ground plane GND and the thirteenth extending portion E13 is arranged in a distribution pattern that uses the stray capacitance between the ground surface GND and the eighth extending portion E8. By designing, the high-frequency current flowing through each antenna element is also distributed, and each stray capacitance can be designed effectively. Further, the ground plane GND can be arranged up to the vicinity of the tenth extending portion E10, and other components (button switch, microphone, FPC, etc.) used for the device can be mounted, and the device can be downsized. There is also an advantage that leads to.

Next, the fifth extending portion E5 will be described.
The fifth extending portion E5 has a pattern arrangement using a stray capacitance with the antenna element AT. However, considering the overall size reduction, it is necessary to reduce the antenna area. The arrangement of the extending part E5 and the antenna element AT is important.
As the fifth extending portion E5, designing a wide width is ideal because it leads to a wide band, but there are cases where it is difficult to achieve both miniaturization depending on the antenna region. Therefore, it is desirable that the width of the fifth extending portion E5 is designed to be narrow and designed to be close to the end of the substrate body 2.

  Furthermore, the pattern width on the fifth extending portion E5 side of the portion where the stray capacitance Cf between the third extending portion E3 and the fifth extending portion E5 is generated is widened to be a wide portion E5a, thereby efficiently arranging the patterns. It is preferable that In consideration of the influence of the stray capacitance Cc between the antenna element AT and the fifth extending portion E5, the wide portion E5a is not a quadrilateral shape but a shape with a corner (triangular shape, trapezoidal shape). Thus, it is possible to control the high-frequency current flowing through the fifth extending portion E5 while effectively using the stray capacitance.

As described above, in the antenna device 10 of the present embodiment, the connection pattern L1, the first extending portion (first base end portion) E1, and the sixth extending portion (second base end portion) E6 are provided in the vicinity of the feeding point FP. Since the annular opening pattern portion S1 is formed between the first and second electrodes, the adverse effect of the capacitance component generated between the peripheral components due to the capacitance component Cd generated in the opening pattern portion S1 can be reduced. High performance can be realized.
In addition, since the eighth extending portion E8 of the third element EL3 extends at an interval in a state of being opposed to the opening pattern portion S1 so that stray capacitance can be generated therebetween, the opening pattern portion A stray capacitance Ch can be generated between S1 and the eighth extending portion E8 facing the impedance, and impedance adjustment at the resonance frequency of the third element EL3 can be performed.

  Further, the eighth extending portion E8 has a first back surface pattern portion R1 connected to the front surface side through the through hole H and patterned on the back surface of the substrate body 2, and the first back surface pattern portion R1 is Since it is formed wider toward the ground surface GND, it is possible to effectively generate a stray capacitance with the sixth extending portion E6 without interfering with the sixth extending portion E6. Further, since the first back surface pattern portion R1 is made wider toward the ground surface GND, the impedance is also lower than that of the sixth extending portion E6, and the opening pattern portion S1 (the first extending portion E1 and the eighth extending portion). The influence of interference can be reduced by the stray capacitance Ch with the existing part E8).

  Further, since the impedance adjustment passive elements (the fifth passive element P5 and the sixth passive element P6) are connected to the first ground connection part G1 and the second ground connection part G2, respectively, the setting of the opening pattern part S1 and The impedance adjustment of each frequency band can be performed by setting two impedance adjusting passive elements.

  Further, each element from the first element EL1 to the fourth element EL4 can generate a stray capacitance between adjacent elements and a stray capacitance between the ground plane GND, the adjacent element and the ground plane GND. Since the antenna element AT of the loading element that does not self-resonate at a desired resonance frequency and the stray capacitance between the elements are effectively used, the double resonance (2 ~ 4 resonances).

  Further, each resonance frequency can be flexibly adjusted by selecting the antenna element AT and the first to fourth passive elements P1 to P4 (changing constants, etc.), and an antenna capable of 2 to 4 resonances according to design conditions Device 10 can be obtained. In this way, each resonance frequency can be flexibly adjusted with one antenna device substrate 1 due to the antenna configuration, so that the resonance frequency can be changed, and the adjustment location by a passive element or the like can be changed according to the application or device. It has become.

  In addition, the design can be made in the plane of the substrate body 2, and the thickness can be reduced as compared with the case where a conventional dielectric block or resin molding is used, and the antenna element AT which is a dielectric antenna is selected. This also enables downsizing and higher performance. Further, there is no need for costs due to molds, design changes, etc., and low costs can be realized.

  Therefore, in the antenna device 10 of the present embodiment, the first passive element P1, the second passive element P2, the third passive element P3, and the fourth passive element P4 correspond to the first connection part C1 and the second connection part C2, respectively. Since it is connected to the third connection part C3 and the fourth connection part C4, it is possible to achieve 2 to 4 resonances by simply selecting the first to fourth passive elements P1 to P4 as appropriate. Communication is possible at one to four resonance frequencies.

  Next, in the example produced based on the antenna device of the present embodiment, the results of measurement of the VSWR characteristics (voltage standing wave ratio) and the radiation pattern in the four resonance mode at each resonance frequency are shown in FIGS. Explanation will be made with reference to FIG.

Each passive element is composed of two first passive elements P1: 3.3 nH inductor and 10 nH inductor (total of 13 nH inductor), second passive element P2: 8.2 nH, third passive element P3: two inductors of 4.7 nH and 5.6 nH (total of 10 nH inductor), two fourth passive elements P4: two of 5.6 nH inductor and 12 nH of inductor (total 18 nH) Inductor) was used. The fifth passive element P5 uses a 0.5 pF capacitor, and the sixth passive element P6 uses an 8.2 nH inductor.
As a result, in the embodiment of the present invention, good VSWR characteristics are obtained as shown in FIG. 7 at each resonance frequency from the first resonance frequency f1 to the fourth resonance frequency f4.

  Regarding the measurement of the radiation pattern, the direction extending toward the ground plane GND in the extending direction of the second extending portion E2 is defined as the X direction, and the direction opposite to the extending direction of the third extending portion E3 is defined as the Y direction. The direction perpendicular to the surface of the substrate body 2 was taken as the Z direction. At this time, vertical polarization, horizontal polarization, and power gain with respect to the ZX plane were measured.

FIG. 8A shows a radiation pattern (ZX plane) at the first resonance frequency f1 in the 920 MHz band, and the average power gain is −5.1 dBi.
FIG. 8B is a radiation pattern (ZX plane) at the second resonance frequency f2 in the 1400 MHz band, and the average power gain is −1.9 dBi.
FIG. 8C is a radiation pattern (ZX plane) at the fourth resonance frequency f4 in the 1920 MHz band, and the average power gain is −0.8 dBi.

  In addition, this invention is not limited to the said embodiment and Example, A various change can be added in the range which does not deviate from the meaning of this invention.

For example, in the above embodiment, the antenna element is provided in the first element, but the antenna element may be provided in other elements. In this case, the length of the element can be shortened by the antenna element, which is suitable when the area occupied by the antenna is small. For example, you may connect an antenna element to the 5th extension part, the 8th extension part, the 13th extension part, and the 10th extension part.
In addition, for antenna elements other than the lowest frequency band using the antenna element (elements other than the first element), the frequency band to be used can be flexibly changed and replaced.

Furthermore, in the present invention, a maximum of four resonances are realized, but other than the lowest frequency band using an antenna element, it is possible to deal with two resonances or three resonances depending on the presence or absence of each passive element. Is possible.
That is, any one or two of the second passive element, the third passive element, and the fourth passive element are connected to the corresponding second connection part, third connection part, and fourth connection part, respectively. It is possible to make two resonances or three resonances.

  DESCRIPTION OF SYMBOLS 1 ... Antenna device board | substrate, 2 ... Board | substrate main body, 10 ... Antenna apparatus, AT ... Antenna element, C1 ... 1st connection part, C2 ... 2nd connection part, C3 ... 3rd connection part, C4 ... 4th connection part, E1 ... 1st extension part (1st base end part), E2 ... 2nd extension part, E3 ... 3rd extension part, E4 ... 4th extension part, E5 ... 5th extension part, E6 ... 1st 6 extending portion (second base end portion), E7 ... 7th extending portion, E8 ... 8th extending portion, E9 ... 9th extending portion, E10 ... 10th extending portion, E11 ... 11th extending Part, E12 ... 12th extension part, E13 ... 13th extension part, EL1 ... 1st element, EL2 ... 2nd element, EL3 ... 3rd element, EL4 ... 4th element, G1 ... 1st ground connection part, G2 ... second ground connection portion, GND ... ground surface, H ... through hole, L1 ... connection pattern, P1 ... first passive element, P2 ... second receiving Element, P3: Third passive element, P4: Fourth passive element, P5: Fifth passive element (passive element for impedance adjustment), P6: Sixth passive element (passive element for impedance adjustment), FP: Feed point, R1 ... 1st back surface pattern part, R2 ... 2nd back surface pattern part, S1 ... Opening pattern part

Claims (3)

An insulating substrate body;
A plurality of antenna elements each having a ground plane and an open end patterned with a metal foil on the substrate body,
The plurality of antenna elements are provided with a common feeding point at a proximal end in the vicinity of the ground plane, and extend from the feeding point toward two different directions from each other. Divided into one of the parts connected to these,
A first ground connection portion having a proximal end connected to the ground surface and a distal end connected in the middle of the first proximal end portion;
A second ground connection portion having a proximal end connected to the ground surface apart from a position where the first ground connection portion is connected and a distal end connected to the middle of the second proximal end portion;
A connection that extends by connecting a distal end side of the first base end portion with respect to the connection portion of the first ground connection portion and a distal end side of the connection portion of the second base end portion with respect to the second ground connection portion. With patterns,
In the vicinity of the feeding point, an annular opening pattern portion is formed between the connection pattern, the first base end portion, and the second base end portion ,
The antenna device , wherein the feeding point is provided between the first ground connection portion and the second ground connection portion . The antenna device according to claim 1,
An antenna device, wherein at least one of the plurality of antenna elements extends at an interval in a state of being opposed to the opening pattern portion so that stray capacitance can be generated therebetween. In the antenna device according to claim 1 or 2,
At least one of the plurality of antenna elements extends with a passive element in the middle,
At least one of the plurality of antenna elements extends with an antenna element of a dielectric antenna,
The plurality of antenna elements extend to the adjacent antenna elements and the ground plane with an interval therebetween so that stray capacitance between adjacent antenna elements and stray capacitance between the ground planes can be generated. An antenna device characterized by being present.