JP6057163B2 - Antenna device - Google Patents

Description

  The present invention relates to an antenna device capable of achieving 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.

  The present invention has been made in view of the above-mentioned problems, and can flexibly adjust each resonance frequency that has been double-resonated. It is an object of the present invention to provide an antenna device that can be thinned and that can effectively flow a high-frequency current through a plurality of antenna elements and that can suppress the influence of peripheral components.

  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 first element and a second element, and the ground surface is A ground main surface portion and a ground side portion protruding from the ground main surface portion to a side portion of the region where the first element and the second element are formed, and the first element is in the vicinity of the ground main surface portion. And a first extending portion extending in a direction away from the ground main surface portion from the feeding point, and the first extending portion in a direction away from the ground side portion. A second extending portion extending from the distal end of the first element, and a base end of the second element is connected to the ground side portion at a position spaced from the ground main surface portion, and is separated from the ground side portion. Wherein the tip with extends along the ground main surface in a direction which is connected to the distal end of the first extending portion for.

In this antenna device, the second element has a base end connected to the ground side portion at a position spaced from the ground main surface portion, extends along the ground main surface portion in a direction away from the ground side portion, and a distal end. Since it is connected to the tip of the first extension part, the end part of the route of the high-frequency current from the first extension part to the second element is connected to the ground plane (ground side part), and the ground plane (ground side) Part and the ground main surface part). A stray capacitance between the second element and the ground main surface portion is generated in the open loop, so that a high-frequency current can flow effectively in the open loop, and there are peripheral components in the open loop or the ground plane. Even when mounted, the influence on the antenna characteristics can be reduced. In addition, peripheral components (such as a microphone, a switch, and FPS) can be mounted on the ground side, and the antenna area can be reduced in size.
In addition, since the first element and the second element extend at an interval from the ground plane so that stray capacitance between the first element and the second element can be generated, the respective stray capacitances are effectively used. Thus, multiple resonance can be achieved.

An antenna device according to a second invention is characterized in that, in the first invention, an antenna element of a dielectric antenna is connected to the second extending portion.
That is, in this antenna device, since the antenna element of the dielectric antenna is connected to the second extending portion, the element length is shortened and the impedance is increased by the antenna element of the loading element that does not self-resonate at a desired resonance frequency. The stray capacitance can be increased, the adjustment of the double resonance can be facilitated, and the size and the antenna characteristics can be improved.
Further, by selecting the antenna element and the passive element connected to the element (changing constants, etc.), it is possible to flexibly adjust each resonance frequency and 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.
Furthermore, it is possible to design in the plane of the substrate body, and it is possible to reduce the thickness compared to the case of 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 antenna device according to a third aspect of the present invention is the antenna device according to the second aspect, further comprising a third element having a pattern formed on the substrate body with a metal foil and having a base end connected in the middle of the second element. A base end is connected to the ground side portion at a position farther from the ground main surface portion than a tip end of the first extension portion, and extends along the ground main surface portion in a direction away from the ground side portion. 3 extending portions, a fourth extending portion extending from the distal end of the third extending portion toward the ground main surface portion, and a direction away from the ground side portion from the distal end of the fourth extending portion A third extension portion extending and connected to the tip of the first extension portion, and the third element of the third extension portion in a direction away from the ground side portion. The antenna element extends from the tip and the tip is the antenna element. Characterized in that it is arranged oppositely.

  That is, in this antenna device, the third element extends from the tip of the third extending portion in the direction away from the ground side portion, and the tip is arranged facing the antenna element. In addition to the resonance frequency of the antenna element mainly including the first element and the resonance frequency of the antenna element mainly including the second element, the resonance frequency of the antenna element mainly including the third element can be obtained. In particular, since the tip of the third element faces the antenna element, the resonance frequency and impedance can be adjusted by the stray capacitance between the third element and the antenna element.

The antenna device according to a fourth invention is the antenna device according to the third invention, wherein the substrate body is patterned with a metal foil, the tip is connected to the middle of the first extending portion, and the base end is separated from the feeding point. A ground connection portion connected to the ground main surface portion at the position is provided, and a passive element for impedance adjustment is connected to the ground connection portion.
That is, in this antenna device, since the impedance adjustment passive element is connected to the ground connection portion, the impedance adjustment of each frequency band can be performed by setting the impedance adjustment passive element.
In addition, since the second element is connected to the ground side portion of the ground surface instead of the open end via a passive element, the second element via the passive element, the first extension portion, and the passive element for impedance adjustment A π-type matching circuit pattern is formed by the ground connection portion via the. Therefore, as will be described later, by setting the passive element of the second element to a high impedance in a desired frequency band, a high-frequency current is generated in the open loop using the stray capacitance between the second element and the ground plane. It becomes possible to flow effectively.

An antenna device according to a fifth invention is the antenna device according to the third or fourth invention, wherein the third element is connected to the second element formed on the surface of the substrate body through a through-hole, It is formed on the back surface.
That is, in this antenna device, the third element is connected to the second element formed on the front surface of the substrate body through the through hole and formed on the back surface of the substrate body, so that the back surface has enough space. By providing the third element, the stray capacitance between the third element and the antenna element can be efficiently used.

The antenna device according to a sixth aspect of the present invention is the antenna device according to any one of the second to fifth aspects, wherein the first element is connected to a tip end of the first extension portion and separated from the ground side portion. A sixth extending portion extending along the surface portion and connected to the base end of the antenna element; and a distal end of the antenna element extending in a direction away from the ground side portion and connected to the antenna element more than the antenna element. It has the 6th extension part extended in the shape of a ring on the direction side spaced apart from a ground side part, It is characterized by the above-mentioned.
That is, this antenna device has the sixth extending portion that is connected to the tip of the antenna element and extends in a ring shape on the direction side away from the ground side than the antenna element. And the stray capacitance between the ground main surface portion and the resonance frequency and impedance can be easily adjusted. In addition, the sixth extending portion is arranged on the side away from the ground side than the antenna element, compared to the case where the antenna element is folded and arranged on the side close to the ground side from the tip of the antenna element. And away from the feeding point.

An antenna device according to a seventh invention is the antenna device according to the sixth invention, wherein the sixth extending portion is divided into a pattern on the front surface side and the back surface side and is connected to each other through a through hole to form an annular shape. It has a pattern part and a back surface pattern part.
That is, in this antenna device, the sixth extending portion has a front surface pattern portion and a rear surface pattern portion which are separately formed in a pattern on the front surface side and the back surface side, and are connected to each other via a through hole. Therefore, it is possible to form the loop-like sixth extending portion by using the back surface having a sufficient space.

The present invention has the following effects.
That is, according to the antenna device of the present invention, the second element extends along the ground main surface portion in a direction away from the ground side portion from the ground side portion at a position separated from the ground main surface portion, and the tip is first. Since it is connected to the tip of one extension part, an open loop is formed between the first extension part, the second element, and the ground plane, stray capacitance is generated, and high frequency current is effectively generated in the open loop. It can flow. Therefore, even if peripheral parts are mounted in the open loop or on the ground plane, the effect on the antenna characteristics can be reduced, and peripheral parts can also be mounted on the ground side, resulting in a smaller antenna area. Is possible.

1 is a wiring diagram showing an antenna device and each stray capacitance in an embodiment of the antenna device according to the present invention. In this embodiment, it is a wiring diagram for demonstrating simply the corresponding element of the resonant frequency in an antenna apparatus. In this embodiment, it is the top view and back view which show an antenna device. In this embodiment, it is the enlarged plan view and enlarged back view of the principal part which show an antenna device. 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. 5 is a graph showing VSWR characteristics (voltage standing wave ratio) at three resonances in an example of an antenna device according to the present invention. In the Example of the antenna device which concerns on this invention, it is a graph which shows the radiation pattern of 900 MHz band and 1800 MHz band.

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

  As shown in FIGS. 1 to 4, the antenna device 1 according to the present embodiment includes an insulating substrate body 2, a ground surface GND that is patterned on the substrate body 2 with a metal foil such as a copper foil, 1st element EL1 and 2nd element EL2 to which 1 passive element P1 and 2nd passive element P2 were connected in the middle, and 3rd element EL3 to which the base end was connected to the middle of this 2nd element EL2 are provided. . The ground plane GND, the first element EL1, and the second element EL2 are formed on the surface of the substrate body 2.

The ground surface GND has a ground main surface portion G1 and a ground side portion G2 protruding from the ground main surface portion G1 to a side portion of a region where the first element EL1 and the second element EL2 are formed. That is, the ground side portion G <b> 2 is formed at one corner of the substrate body 2. The ground main surface portion G1 is provided with a mounting region for RF circuit components and the like.
The first element EL1 includes a first extending portion E1 provided with a feeding point FP at a proximal end in the vicinity of the ground main surface portion G1, and extending in a direction away from the ground main surface portion G1 from the feeding point FP, A second extending portion E2 extending from the tip of the first extending portion E1 in a direction away from the side portion G2.
In addition, an antenna element AT of a dielectric antenna is connected to the second extending portion E2.

  The second element EL2 has a proximal end connected to the ground side portion G2 at a position spaced from the ground main surface portion G1, and extends along the ground main surface portion G1 in a direction away from the ground side portion G2. Is connected to the tip of the first extension E1. The phrase “along the ground main surface portion G1” means more specifically along the end side of the opposing ground main surface portion G1.

  The second element EL2 is connected to the ground main surface portion G1 in a direction away from the ground side portion G2 with a base end connected to the ground side portion G2 at a position farther from the ground main surface portion G1 than the tip of the first extending portion E1. A third extending portion E3 extending along, a fourth extending portion E4 extending from the tip of the third extending portion E3 toward the ground main surface portion G1, and a tip of the fourth extending portion E4 A fifth extending portion E5 extending in a direction away from the ground side portion G2 and connected to the tip of the first extending portion E1. In the present embodiment, the second passive element P2 is mounted and connected in the middle of the third extending portion E3.

Further, the first element EL1 is connected to the tip of the antenna element AT extending in a direction away from the ground side portion G2, and extends in a ring shape on the direction side away from the ground side portion G2 than the antenna element AT. It has the 6th extension part E6.
In the present embodiment, the two first passive elements P1 are mounted in series and connected to the second extending portion E2.

  The sixth extending portion E6 has a front surface pattern portion E6a and a rear surface pattern portion E6b that are separately formed on the front surface side and the back surface side, and are connected to each other through the through holes H to form an annular shape. . The front surface pattern portion E6a and the back surface pattern portion E6b are formed in an L shape extending once from the front end of the antenna element AT to the ground main surface portion G1 and then bending and extending away from the ground side portion G2. A pattern is formed, and the substrate body 2 is sandwiched between them. That is, a rectangular space is vacated at the corner on the sixth extending portion E6 side of the substrate body 2 (the corner opposite to the ground side portion G2), and a fixing screw hole or the like is provided in this portion. It is also possible.

The third element EL3 extends from the tip of the third extending portion E3 in a direction away from the ground side portion G2, and the tip is arranged to face the antenna element AT.
The third element EL3 is connected to the second element EL2 formed on the surface of the substrate body 2 through the through hole H, and is formed on the back surface of the substrate body 2.
The third passive element P3 is connected to the third element on the way.

  In addition, the antenna device 1 is formed by patterning the substrate body 2 with a metal foil such as a copper foil, the tip is connected to the middle of the first extending portion E1, and the base end is separated from the feeding point FP at the ground. A ground connection portion EL4 connected to the main surface portion G1 is provided. An impedance adjusting passive element P4 is connected to the ground connection portion EL4.

  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: 108.0 mm, a transversal direction: 51.5 mm, and thickness: 1.0 mm. In addition, the dimensions of the antenna region (region in which the ground main surface portion G1 and the ground side portion G2 are not formed) in the substrate body 2 are as follows: the longitudinal direction of the substrate body 2: 11.5 mm, and the short direction of the substrate body 2: 37. 0.0 mm.

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 ground main surface portion G1 proximal end side, 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. Depending on the desired frequency, the dielectric 101 used for the antenna element AT may be a magnetic material or a composite material in which a dielectric and a magnetic material are mixed.

The antenna element AT is mounted with the central axis shifted in a direction away from the ground main surface part G1 from the tip of the first extension part E1, and the base end is arranged at a position facing the fourth extension part E4. Yes.
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.
For example, an inductor, a capacitor, or a resistor is employed as the first passive element P1 to the third passive element P3 and the impedance adjusting passive element P4.

  In the antenna device 1 of the present embodiment, each element from the first element EL1 to the third element EL3 can generate stray capacitance between adjacent elements and stray capacitance between the ground plane GND, respectively. The adjacent elements and the ground plane GND are extended with a space therebetween.

  That is, as shown in FIG. 1, the stray capacitance Ca between the sixth extending portion E6 and the ground main surface portion G1, the stray capacitance Cb between the antenna element AT and the ground main surface portion G1, and the antenna element AT. The stray capacitance Cc between the third element EL3, the stray capacitance Cd between the second extending portion E2 and the third element EL3, and the stray capacitance between the third extending portion E3 and the ground main surface portion G1. Ce can be generated.

  Next, the resonance frequency in the antenna device 1 of the present embodiment will be described with reference to FIG.

In the antenna device 1 of the present embodiment, for example, as shown in FIG. 6, multiple resonances are made to three of the first resonance frequency f1, the second resonance frequency f2, and the third resonance frequency f3.
The first resonance frequency f1 is in a low frequency band (for example, 900 MHz band) of the three resonance frequencies, and the antenna element AT, the first element EL1, the ground connection portion EL4, and each stray capacitance Ca. ~ Cd and determined and adjusted.
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 two first passive elements P1.
Therefore, the first resonance frequency f1 is adjusted mainly at a portion surrounded by a broken line A1 in FIG.
Thus, for the first resonance frequency f1, the resonance frequency and impedance are flexibly adjusted by setting the antenna element AT, the length of the first element EL1, the first passive element P1, and each of the stray capacitances. Is possible.

Next, the second resonance frequency f2 includes the third element EL3, the first extending portion E1, the ground connecting portion EL4, the fifth extending portion E5, the fourth extending portion E4, and the stray capacitance. Determined and adjusted by Cc and Cd.
The impedance at the second resonance frequency f2 is determined by the stray capacitances Cc and Cd, the second passive element P2, and the third extending portion E3.
Furthermore, the final adjustment of the second resonance frequency f2 can be flexibly adjusted using the third passive element P3.

Therefore, the second resonance frequency f2 is adjusted mainly at a portion surrounded by a two-dot chain line A2 in FIG.
Thus, for the second resonance frequency f2, the lengths of the third element EL3, the first extending portion E1, the ground connecting portion EL4, the fifth extending portion E5, and the fourth extending portion E4, and the third passive frequency f2 are obtained. The resonant frequency and impedance can be flexibly adjusted by setting the element P3 and the stray capacitances Cc and Cd.

Next, the third resonance frequency f3 includes the first extension part E1, the ground connection part EL4, the third extension part E3, the fourth extension part E4, the fifth extension part E5, It is determined and adjusted by the stray capacitance Ce.
The impedance at the third resonance frequency f3 is determined by the stray capacitance Ce.
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.

As described above, for the third resonance frequency f3, the resonance frequency and the impedance are flexibly set by the lengths of the first extending portion E1 and the second element EL2, the second passive element P2, and the stray capacitance Ce. Can be adjusted.
The final impedance adjustment of the first to third resonance frequencies f1 to f3 can be flexibly adjusted using the impedance adjustment passive element P4.

Next, the effect of the second element EL2 will be described.
In the present embodiment, as shown in FIG. 4, the end portion of the route of the high-frequency current from the first extending portion E1 to the second element EL2 is connected to the ground plane GND (ground side portion G2), and the ground plane GND. An open loop R for high-frequency current is formed between the ground side portion G2 and the ground main surface portion G1. Specifically, the power supply point FP is connected to the ground side part G2 through the first extension part E1, the fifth extension part E5, the fourth extension part E4, and the third extension part E3 in this order. ing.

As a result, since the ground plane GND (ground side portion G2) can be arranged on the end side, peripheral components (microphone, switch, FPS, etc.) can be mounted on the ground side portion G2, and the antenna area can be reduced in size. become.
In addition, the stray capacitance Ce between the second element EL2 and the ground main surface portion G1 is generated in the open loop R, and the open loop R can also effectively flow a high-frequency current. Even when peripheral components are mounted on the surface GND, the influence on the antenna characteristics can be reduced.

Next, the effect of the third element EL3 will be described.
In the present embodiment, the impedance adjustment of the resonance frequency constituted by the third element EL3 is performed by setting the second element EL2 and the second passive element P2. Since the second element EL2 is connected to the ground side G2 of the ground plane GND instead of the open end via the second passive element P2, the second element EL2 and the first element EL2 via the second passive element P2 are connected to the first extension EL2. The existing portion E1 and the ground connection portion EL4 through the impedance adjusting passive element P4 constitute a π-type matching circuit pattern.

  Here, since the second passive element P2 effectively allows a high-frequency current to flow in the open loop R using the stray capacitance Ce between the second element EL2 and the ground main surface portion G1, the second passive element P2 has a high impedance in a desired frequency band. It is desirable to set to. Therefore, the flow of the high-frequency current viewed from the third element EL3 is difficult to flow to the second element EL2 side, and an effective high-frequency current flow is generated between the fourth extending portion E4 and the third element EL3. To do. From this point of view, the installation position of the second passive element P2 is preferably the fourth extension part E4 or the fifth extension part E5, but depending on the installation position of the second passive element P2 depending on the desired frequency band, the third element The flow of the high-frequency current to the second element EL2 (particularly, the third extending portion E3) viewed from EL3 can be controlled.

  Thus, in the antenna device 1 of the present embodiment, the second element EL2 is connected to the ground side part G2 at a position away from the ground principal surface part G1, and the ground principal surface part in a direction away from the ground side part G2. Since the tip extends along G1 and the tip is connected to the tip of the first extension E1, the opening loop R can also effectively flow a high-frequency current, and the inside of the opening loop R and the ground surface GND. Even when peripheral components are mounted on the antenna, the influence on the antenna characteristics can be reduced. In addition, peripheral components (such as a microphone, a switch, and FPS) can be mounted on the ground side, and the antenna area can be reduced in size.

In addition, since the first element EL1 and the second element EL2 extend at an interval from the ground plane GND so as to be able to generate stray capacitance between the first plane EL1 and the second plane EL2, respectively, each floating capacitance is effectively used. Can be used to achieve multiple resonances.
Furthermore, since the antenna element AT of the dielectric antenna is connected to the second extending portion E2, the element length is shortened and the impedance is increased by the antenna element AT of the loading element that does not self-resonate at a desired resonance frequency, and floating. Capacitance can be increased, adjustment of double resonance can be facilitated, and miniaturization and improvement of antenna characteristics can be achieved.

  Further, by selecting the antenna element AT and each passive element (changing constants, etc.), it is possible to flexibly adjust each resonance frequency and obtain an antenna device capable of resonance 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.

  Furthermore, it is possible to design in the plane of the substrate body 2, and it is possible to reduce the thickness as compared with the case of using a conventional dielectric block or resin molded body, and to select the antenna element AT which is a dielectric antenna. 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.

  In addition, the third element EL3 extends from the tip of the third extending portion E3 in the direction away from the ground side portion G2, and the tip is arranged facing the antenna element AT. An antenna element mainly composed of the third element EL3 in addition to the first resonance frequency f1 composed mainly of the first element EL1 and the third resonance frequency f3 composed mainly of the second element EL2. The second resonance frequency f2 can be obtained. In particular, since the tip of the third element EL3 faces the antenna element AT, the resonance frequency and impedance can be adjusted by the stray capacitance between the third element EL3 and the antenna element AT.

Further, since the impedance adjustment passive element P4 is connected to the ground connection portion EL4, the impedance adjustment of each frequency band can be performed by setting the impedance adjustment passive element P4.
Further, since the second element EL2 is connected to the ground side portion G2 of the ground surface GND instead of the open end via the second passive element P2, the second element EL2, the first extending portion E1, and the ground connection portion EL4. To form a π-type matching circuit pattern, and by setting the second passive element P2 of the second element EL2 to a high impedance in a desired frequency band, the stray capacitance between the second element EL2 and the ground plane GND A high-frequency current can be effectively passed through the opening loop R using Ce.

  Further, since the third element EL3 is connected to the second element EL2 formed on the front surface of the substrate body 2 via the through hole H and formed on the back surface of the substrate body 2, the back surface has a sufficient space. By providing the third element EL3, the stray capacitance Cc between the third element EL3 and the antenna element AT can be efficiently used.

  In addition, since it has a sixth extending portion E6 that is connected to the tip of the antenna element AT and extends annularly on the direction side away from the ground side portion G2 from the antenna element AT, the sixth extending portion The stray capacitance Ca between E6 and the ground main surface portion G1 increases, and the resonance frequency and impedance can be easily adjusted. In addition, since the sixth extending portion E6 is disposed on the side away from the ground side portion G2 relative to the antenna element AT, the sixth extending portion E6 is folded from the front end of the antenna element AT to the side closer to the ground side portion G2. Compared with the case where it is done, it can keep away from the feeding point FP.

  Further, the sixth extending portion E6 has a front surface pattern portion E6a and a back surface pattern portion E6b which are separately formed in patterns on the front surface side and the back surface side, and are connected to each other through the through holes H to form an annular shape. Therefore, the loop-shaped sixth extending portion E6 can be formed by using the back surface having enough space.

  Next, in the example manufactured 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 three resonances at each resonance frequency are shown in FIGS. This will be described with reference to FIG.

Each passive element includes two first passive elements P1: 4.3 nH inductor, second passive element P2: 0.3 pF capacitor, third passive element P3: 8.2 nH inductor, 4 Passive element P4: A 6.8 nH inductor was used.
As a result, in the embodiment of the present invention, good VSWR characteristics are obtained as shown in FIG. 6 at each resonance frequency from the first resonance frequency f1 to the third resonance frequency f3.

  Further, regarding the measurement of the radiation pattern, the extending direction of the first extending portion E1 and the direction toward the ground plane GND is defined as the X direction, and the extending direction of the second extending portion E2 (the extending of the antenna element AT). Direction) was the Y direction, and the direction perpendicular to the surface of the substrate body 2 was the Z direction. At this time, the vertical polarization, horizontal polarization and power gain with respect to the YZ plane were measured.

FIG. 7A shows a radiation pattern (YZ plane) at the first resonance frequency f1 in the 900 MHz band, and the average power gain was −1.5 dBi. The VSWR is 1.58 (resonance frequency: 890.6 MHz) and the bandwidth is 90.6 MHz (VSWR ≦ 3.0), and a good antenna gain and a wider band are obtained.
FIG. 7B is a radiation pattern (YZ plane) at the second resonance frequency f2 in the 1800 MHz band, and the average power gain is −3.5 dBi. The VSWR is 1.07 (resonance frequency: 1815.6 MHz) and the bandwidth is 803.1 MHz (VSWR ≦ 3.0), and a good antenna gain and a wider band are obtained.

  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, an antenna element may be connected to the third element.

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 above-described embodiment, three resonances are realized, but two resonances are formed by only the first element and the second element without providing the third element or without connecting the third passive element. It doesn't matter.

  In addition, as described above, it is preferable to connect the antenna element to be a part of the element, but the second extending portion that is extended only by a metal foil such as a copper foil may be used without connecting the antenna element. . At this time, in order to increase the impedance, at least a part of the second extension part is formed into a narrow pattern narrower than the other parts, or a meander pattern extending in a certain direction as a whole while being folded back zigzag. It is preferable. Furthermore, when there is a margin in the substrate size, a part of the element may be replaced with a pattern in which a linear or plate-like metal is folded. Moreover, you may make it the pattern swirled in shapes, such as a spiral shape, using a through hole with respect to the front and back of the same board | substrate body.

  DESCRIPTION OF SYMBOLS 1 ... Antenna apparatus, 2 ... Board | substrate main body, AT ... Antenna element, E1 ... 1st extension part, E2 ... 2nd extension part, E3 ... 3rd extension part, E4 ... 4th extension part, E5 ... 1st 5 extending portion, E6 ... 6th extending portion, E6a ... front surface pattern portion, E6b ... back surface pattern portion, EL1 ... 1st element, EL2 ... 2nd element, EL3 ... 3rd element, EL4 ... ground connection portion, G1 ... ground main surface portion, G2 ... ground side portion, GND ... ground surface, H ... through hole, P1 ... first passive element, P2 ... second passive element, P3 ... third passive element, P4 ... passive element for impedance adjustment, FP ... Feed point

Claims (5)

An insulating substrate body;
A ground plane patterned with a metal foil on the substrate body, and a first element and a second element,
The ground surface has a ground main surface portion, and a ground side portion protruding from the ground main surface portion to a side portion of a region where the first element and the second element are formed,
The first element is provided with a feeding point at a proximal end in the vicinity of the ground main surface portion, and extends in a direction away from the ground main surface portion from the power feeding point; and
A second extending part extending from the tip of the first extending part in a direction away from the ground side part,
The second element has a base end connected to the ground side portion at a position spaced from the ground main surface portion, extends along the ground main surface portion in a direction away from the ground side portion, and a distal end of the second element. Connected to the tip of the first extension ,
An antenna element of a dielectric antenna is connected to the second extension part,
A third element having a pattern formed of a metal foil on the substrate body and having a base end connected in the middle of the second element,
The second element has a base end connected to the ground side portion at a position farther from the ground main surface portion than a tip end of the first extending portion, and is along the ground main surface portion in a direction away from the ground side portion. A third extension extending,
A fourth extending portion extending from the tip of the third extending portion toward the ground main surface portion;
A fifth extending portion extending in a direction away from the ground side portion from the tip of the fourth extending portion and connected to the tip of the first extending portion;
The third element extends from the tip of the third extending portion in a direction away from the ground side, and the tip is arranged to face the antenna element. Antenna device to do. The antenna device according to claim 1 ,
A ground connection portion formed by patterning a metal foil on the substrate body and having a distal end connected in the middle of the first extending portion and a base end connected to the ground main surface portion at a position separated from the feeding point. Prepared,
An antenna device, wherein an impedance adjusting passive element is connected to the ground connection portion. In the antenna device according to claim 1 or 2 ,
The antenna device, wherein the third element is connected to the second element formed on the surface of the substrate body through a through hole and formed on the back surface of the substrate body. An insulating substrate body;
A ground plane patterned with a metal foil on the substrate body, and a first element and a second element,
The ground surface has a ground main surface portion, and a ground side portion protruding from the ground main surface portion to a side portion of a region where the first element and the second element are formed,
The first element is provided with a feeding point at a proximal end in the vicinity of the ground main surface portion, and extends in a direction away from the ground main surface portion from the power feeding point; and
A second extending part extending from the tip of the first extending part in a direction away from the ground side part,
The second element has a base end connected to the ground side portion at a position spaced from the ground main surface portion, extends along the ground main surface portion in a direction away from the ground side portion, and a distal end of the second element. Connected to the tip of the first extension,
An antenna element of a dielectric antenna is connected to the second extension part,
The first element is connected to the tip of the antenna element extending in a direction away from the ground side, and is extended in an annular shape on the side away from the ground side than the antenna element. And an antenna device. The antenna device according to claim 4 , wherein
The sixth extending portion has a front surface pattern portion and a back surface pattern portion that are separately formed in a pattern on the front surface side and the back surface side, and are connected to each other via a through hole to form an annular shape. Antenna device to do.