JP2019022145A - Antenna device - Google Patents

Abstract

To provide an antenna device which allows for adjustment of resonance frequency and compaction even if a ground pattern is not arranged oppositely along antenna elements, and can realize good antenna performance even if it is provided separately from the main substrate of the circuit.SOLUTION: An antenna device includes a substrate body 2, a ground pattern 3, and a first element 4, where the first element 4 has a first extension E1 extending from a feeding point toward the other side 2b of the substrate body, a second extension E2 extending from the tip of the first extension toward the other end side of the substrate body, and an element branch connection E7 extending from the way of the second extension along the first extension toward one side 2a of the substrate body. The ground pattern has a first ground extension G1 extending from the vicinity of the feeding point along the second extension, and a second ground extension G2 extending from the first ground extension to project between the first extension and the element branch connection.SELECTED DRAWING: Figure 1

Description

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

  In recent years, in communication equipment, an antenna device has been developed that can flexibly adjust each resonance frequency that has been double-resonated, and can easily and inexpensively ensure antenna performance according to the application and equipment (for example, Patent Document 1). ). Since these antenna devices are provided with a ground pattern and a plurality of elements, each of which is formed with a metal foil on the surface of the substrate body, the respective stray capacitances between the elements and between the ground patterns are effectively used. By doing so, a double resonance is achieved.

JP 2017-92978 A

However, the following problems remain in the above-described conventional technology.
That is, in the conventional antenna device described above, the design is performed by using the stray capacitance generated between the antenna element and the wide ground pattern that is opposed to the antenna element. If not, there is an inconvenience that it is difficult to adjust the resonance frequency and reduce the size. Also, since the antenna pattern is formed in the antenna occupation area provided on the main board of the circuit, the antenna performance is largely due to the ground size of the main board, and it is difficult to realize good performance depending on the design conditions. . Further, when the antenna device is provided separately from the main board of the circuit, it cannot be designed using the ground of the main board.

  The present invention has been made in view of the above-described problems, and it is possible to adjust the resonance frequency and reduce the size even if a wide ground pattern is not disposed opposite to the antenna element. It is an object of the present invention to provide an antenna device that can achieve good antenna performance even if provided separately.

  The present invention employs the following configuration in order to solve the above problems. That is, an antenna device according to a first aspect of the present invention includes a rectangular and insulating substrate body, a ground pattern patterned with a metal foil on one end side of the substrate body and connected to the ground, and a metal foil on the substrate body. A first element that is patterned and connected to a feeding point, the feeding point being arranged on one side of both sides extending from one end of the substrate body to the other end, and the ground pattern A ground main surface portion formed on one end side of the substrate body apart from the feeding point, and a ground connection portion arranged from the ground main surface portion to the vicinity of the feeding point, wherein the first element is A first extending portion extending from the feeding point toward the other side of the substrate body, and a second extending from the tip of the first extending portion toward the other end side of the substrate body. An extension part and the second extension An element branch portion extending toward one side of the substrate main body along the first extending portion from the middle of the ground pattern, and the ground pattern is connected to the ground connecting portion. A first ground extension extending from the vicinity along the second extension, and a protrusion extending between the first extension and the element branch from the first ground extension. And a second ground extending portion.

  In this antenna device, the ground pattern includes a first ground extending portion that extends from the vicinity of the feeding point along the second extending portion, a first extending portion from the first ground extending portion, and an element branching portion. And a second ground extension portion that protrudes and extends between the first extension portion, the base end side of the second extension portion, the element branch portion, and the second ground extension from the feeding point. When the high-frequency current flows in a loop shape in the part and the first ground extension part, a resonance frequency different from that of the first element can be generated. In addition, the stray capacitance is generated between the second ground extension portion, the first extension portion, the base end side of the second extension portion, and the element branch portion, thereby adjusting the resonance frequency and increasing the bandwidth. be able to. Further, the first element, the loop-like portion for generating a high-frequency current and the ground main surface portion can be arranged side by side in one direction, and can be provided on an elongated substrate body, facilitating miniaturization.

The antenna device according to a second invention is the antenna device according to the first invention, wherein the tip end portion of the second ground extension portion is a wide tip portion that extends to the first extension portion side and the element branching portion side. It is characterized by.
That is, in this antenna device, the distal end portion of the second ground extending portion is a wide distal end portion that extends to the first extending portion side and the element branching portion side, so that it corresponds to the width of the wide distal end portion. The stray capacitance generated between the first extending portion, the proximal end side of the second extending portion, and the element branching portion can be adjusted.

An antenna device according to a third invention is characterized in that, in the first or second invention, the antenna device has an additional element portion extending from the tip of the element branching portion toward the other end of the substrate body. And
That is, in this antenna apparatus, since it has the additional element part extended toward the other end side of a board | substrate body from the front-end | tip of an element branch part, it is between an additional element part with an open end, and a 1st element. A stray capacitance is generated in the first, and another resonance frequency can be generated.

An antenna device according to a fourth invention is characterized in that, in any one of the first to third inventions, an antenna element of a dielectric antenna is connected in the middle of the second extending portion.
That is, in this antenna device, since the antenna element of the dielectric antenna is connected in the middle of the second extending portion, the element length is shortened and the high impedance is achieved by the antenna element of the loading element that does not self-resonate at a desired resonance frequency. And an increase in stray capacitance, making it easy to adjust the double resonance and reducing the size and improving the antenna characteristics.

The antenna device according to a fifth aspect of the present invention is characterized in that, in any one of the first to fourth aspects, a passive element is connected to the proximal end or midway of the second extending portion.
The antenna device according to a sixth aspect of the invention is characterized in that, in the third aspect of the invention, a passive element is connected to the proximal end or midway of the additional element portion.
That is, in these antenna devices, since the passive element is connected to the base end or the middle of the second extension part or the additional element, each resonance frequency can be flexibly adjusted by selecting the passive element, and the design conditions An antenna device capable of achieving multiple resonance according to the above can be obtained. Thus, since each resonance frequency can be flexibly adjusted in terms of the antenna configuration, the resonance frequency can be switched, and the adjustment location by a passive element or the like can be changed according to the application or device.

An antenna device according to a seventh invention is the antenna device according to any one of the first to sixth inventions, wherein the substrate main body has a thin plate shape extending in a strip shape, and the ground main surface portion is one end side of the substrate main body. It is characterized by extending in a strip shape.
That is, in this antenna device, the substrate main body has a thin plate shape extending in a band shape, and the ground main surface portion extends in a band shape on one end side of the substrate main body, so that the whole can be elongated and reduced in size.

The present invention has the following effects.
According to the antenna device of the present invention, the ground pattern includes a first ground extending portion extending from the vicinity of the feeding point along the second extending portion, and a first extending portion extending from the first ground extending portion. Since it has the 2nd ground extension part which protruded and extended between the element branch parts, the high frequency current from a feeding point flows in a loop shape via an element branch part, Can generate different resonant frequencies. In addition, since the stray capacitance is generated between the element branch portion and the periphery thereof, the resonance frequency can be adjusted and the bandwidth can be increased.
That is, the resonance frequency can be easily adjusted and reduced in size even if a wide ground pattern is not disposed opposite to the antenna element. Further, it is possible to obtain good antenna performance while suppressing the influence of the circuit main board and the like.
Therefore, the antenna device of the present invention can easily achieve multiple resonances corresponding to various applications and devices, and can save space.

In one Embodiment of the antenna device which concerns on this invention, it is a top view which shows the positional relationship of each element. In this embodiment, it is a wiring diagram which shows the main area | regions which contribute to each resonance frequency. In this embodiment, it is a wiring diagram which shows the stray capacitance produced with an antenna apparatus. In this embodiment, it is the perspective view (a) which shows an antenna element, a top view (b), a front view (c), and a bottom view (d). In this embodiment, it is a graph which shows the VSWR characteristic (voltage standing wave ratio).

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

  As shown in FIGS. 1 and 2, the antenna device 1 according to the present embodiment is formed into a rectangular and insulating substrate body 2, and the substrate body 2 is patterned with a metal foil such as a copper foil and connected to the ground GND. The ground pattern 3 is provided with a first element 4 and a second element 5 that are patterned on the substrate body 2 with a metal foil such as a copper foil and connected to the feeding point FP.

The feeding point FP is arranged on one side 2 a of both sides extending from one end of the substrate body 2 to the other end.
The first element 4 includes a first extending part E1 extending from the feeding point FP toward the other side 2b of the substrate body 2, and the other end side of the substrate body 2 from the tip of the first extending part E1. A second extending portion E2 extending toward the substrate, and an element branching portion E7 extending toward one side of the substrate body 2 along the first extending portion E1 from the middle of the second extending portion E2. And have.

That is, the element branching portion E7 extends toward one side 2a of the substrate body 2, and the first branching portion E1 and the base end side of the second extending portion E2 and the element branching portion E7 A letter-shaped pattern is formed.
The base end side of the second extending portion E2 (from the connecting portion with the first extending portion E1 to the connecting portion with the element branching portion E7) has a wide base end portion E2a formed wider than the tip end side. Has been.

The ground pattern 3 is separated from the feeding point FP and is formed on one end side of the substrate body 2. The ground main surface portion 3 a extends from the ground principal surface portion 3 a toward the other end side of the substrate body 2. And a ground connection portion 3b arranged up to the vicinity.
The feeding point FP is disposed on one side (side 2a) of both sides extending from one end to the other end of the substrate body 2, and the ground connection portion 3b also extends along the one side 2a. doing.

The ground pattern 3 is connected to the ground connection portion 3b and extends from the vicinity of the feeding point FP along the second extension portion E2, and the first ground extension portion G1 to the first It further has a second ground extending portion G2 that protrudes and extends between the extending portion E1 and the element branching portion E7.
That is, the first ground extending portion G1 extends along the second extending portion E2 from the ground connecting portion 3b toward the other end side of the substrate body 2. Further, the second ground extension part G2 extends from the tip of the first ground extension part G1 so as to protrude between the first extension part E1 and the element branch part E7.

In addition, as a connection point with the ground GND, a first connection point Ga is provided at one end of the substrate main body 2 of the first ground extension G1, and the other end of the substrate main body 2 of the first ground extension G1. A second connection point Gb is provided at the side end.
That is, the ground connection portion 3b is connected to the first connection point Ga arranged on the left side of the feeding point FP with the tip side bent toward the first ground extension portion G1.
The second ground extension part G2 extends from the second connection point Gb arranged on the right side of the feeding point FP toward the base end side of the second extension part E2.

The distal end portion of the second ground extending portion G2 is a wide distal end portion G2a that extends to the first extending portion E1 side and the element branching portion E7 side.
In addition, the antenna device 1 according to the present embodiment includes the additional element portion E8 extending from the tip of the element branching portion E7 toward the other end of the substrate body 2.

The second element 5 has a third extending portion E3 extending along the ground connection portion 3b from the tip end of the first extending portion E1 toward the ground main surface portion 3a.
The second element 5 includes a fourth extending portion E4 extending from the tip of the third extending portion E3 toward the ground connection portion 3b, and the other end of the substrate body 2 from the tip of the fourth extending portion E4. And a fifth extending portion E5 extending along the ground connection portion 3b toward the side. That is, the second element 5 is formed in a U shape at the tip side.

The first element 4 includes a ninth extending portion E9 extending from the tip of the second extending portion E2 along the first extending portion E1, and one end of the substrate body 2 from the tip of the ninth extending portion E9. It further has a tenth extending portion E10 extending along the second extending portion E2 toward the side. That is, the first element 4 is formed in a U shape at the tip end side, and the ninth extending portion E <b> 9 is disposed in the vicinity of the other end of the substrate body 2.
The distal end of the additional element portion E8 is arranged to face the open end of the first element 4 (the distal end of the tenth extending portion E10). In this way, it is preferable that the tip of the additional element portion E8 and the open end of the first element 4 are arranged to face each other in the front, but the direction toward the one of the two side edges 2a and 2b of the substrate body 2 is mutually. It does not matter if it is shifted to.

In the middle of the second extending portion E2, an antenna element AT of a dielectric antenna is connected. The antenna element AT is connected to the front end side of the connection portion between the second extending portion E2 and the element branching portion E7.
In addition, passive elements are respectively connected to the base ends or in the middle of the second extending portion E2 and the third extending portion E3. In the present embodiment, the first passive element P1 is connected in the middle of the second extending part E2, and the second passive element P2 is connected to the base end of the third extending part E3.
Further, the base end of the first extending portion E1 and the base end of the ground connection portion 3b are connected by a third passive element P3, and the fourth passive element P4 is connected to the base end of the additional element portion E8. ing. Note that the third passive element P3 may not be mounted.

The substrate body 2 has a thin plate shape extending in a band shape, and the ground main surface portion 3 a extends in a band shape on one end side of the substrate body 2. The substrate body 2 has a rectangular shape of 11 mm × 141 mm with a thickness of 0.8 mm, for example.
The substrate body 2 is a general printed circuit board, and in this embodiment, a printed circuit board made of glass epoxy resin or the like is employed.
The length from the first connection point Ga to the end of the ground main surface portion 3a (one end of the substrate body 2) is 1/4 of the wavelength of the lowest resonance frequency (the first resonance frequency f1 of the present invention). The length is preferably about the wavelength. In the present embodiment, the length from the first connection point Ga to the end of the ground main surface portion 3a is 90 mm.
Note that a circuit component or the like may be mounted in the area of the ground main surface portion 3a.
For example, an inductor, a capacitor, a resistor, or a jumper line is used as each passive element.

The feeding point FP is connected to a feeding point of a high-frequency circuit (not shown) provided on another main board or the like via 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 first ground extending portion G1, 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 122 such as Ag is formed on the surface of a dielectric 121 such as ceramic as shown in FIG. is there.
As the antenna element AT, elements having different lengths, widths, conductor patterns, and the like may be selected according to the setting of the resonance frequency and the like. Depending on the desired frequency, the dielectric 121 used in the antenna element AT may be a magnetic material or a composite material in which a dielectric and a magnetic material are mixed.

In the antenna device 1 of this embodiment, stray capacitance is generated as follows.
That is, as shown in FIG. 3, the stray capacitance Ca between the tip end side of the second extending portion E2 (the tip side of the antenna element AT) and the tenth extending portion E10, the antenna element AT, and the tenth extending portion. The stray capacitance Cb between the existing portion E10, the stray capacitance Cc between the second ground extending portion G2 and the element branching portion E7, and the base ends of the second ground extending portion G2 and the second extending portion E2. Stray capacitance Cd between the side (wide base end portion E2a), stray capacitance Ce between the second ground extension portion G2 and the first extension portion E1, an additional element portion E8, and a tenth extension portion. A stray capacitance Cf between E10, a stray capacitance Cg between the fourth extending portion E4 and the ground main surface portion 3a, a stray capacitance Ch between the fifth extending portion E5 and the ground connection portion 3b, The stray capacitance Ci between the fifth extending part E5 and the third extending part E3, the fifth extending part E5 and the first extending part 1 and the stray capacitance Cj between a and stray capacitance Ck between the additional element portion E8 and the second extending portion E2 can be generated.

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

In the antenna device 1 of the present embodiment, as shown in FIG. 5, the first resonance frequency f1, the second resonance frequency f2, the third resonance frequency f3, and the fourth resonance frequency f4 from the lowest frequency. In order, double resonance is realized in four frequency bands.
In this measurement, the following passive elements were used.
First passive element P1: Inductor with L = 4.7 nH Second passive element P2: Inductor with L = 2.7 nH Third passive element P3: Unmounted fourth passive element P4: Inductor with L = 5.6 nH

“About the first resonance frequency f1”
The frequency of the first resonance frequency f1 can be set and adjusted by the first element 4 and the antenna element AT.
Further, the impedance adjustment of the first resonance frequency f1 can be performed by setting each of the stray capacitances Ca, Cb, Cc, Cd, Ce, and Cf.
Furthermore, the final frequency adjustment can be flexibly performed by selecting the first passive element P1.
In this way, the first resonance frequency f1 is adjusted mainly at the portion of the one-dot chain line A1 in FIG.

“About the second resonance frequency f2”
The frequency of the second resonance frequency f2 can be set and adjusted by the second element 5 and the first extending portion E1.
Further, the impedance adjustment of the second resonance frequency f2 can be performed by setting each of the stray capacitances Cc, Cd, Ce, Cg, Ch, Ci, and Cj.
Further, the final frequency adjustment can be flexibly performed by selecting the second passive element P2.
Thus, the second resonance frequency f2 is adjusted mainly at the portion indicated by the broken line A2 in FIG.

“About the third resonance frequency f3”
The frequency of the third resonance frequency f3 can be set and adjusted by the base end side of the element branch portion E7, the additional element portion E8, the first extending portion E1, and the second extending portion E2.
Further, the impedance adjustment of the third resonance frequency f3 can be performed by setting each of the stray capacitances Cc, Cd, Ce, Cf, and Ck.
Furthermore, the final frequency adjustment can be flexibly performed by selecting the first passive element P1.
In this way, the third resonance frequency f3 is adjusted mainly at the portion of the two-dot chain line A3 in FIG.

“About the fourth resonance frequency f4”
The frequency of the fourth resonance frequency f4 is determined by the first extending portion E1, the base end side of the second extending portion E2, the element branching portion E7, the first ground extending portion G1, and the second ground extending portion G2. Can be set and adjusted.
The impedance adjustment of the fourth resonance frequency f4 can be performed by setting each of the stray capacitances Cc, Cd, Ce, and Cj.
Furthermore, the final frequency adjustment can be flexibly performed by the stray capacitance Cd.
In this way, the fourth resonance frequency f4 is adjusted mainly at the portion of the broken line A4 in FIG.

  The final impedance adjustment at each of the resonance frequencies f1, f2, f3, and f4 can be flexibly performed by controlling the flow of the high-frequency current flowing to the ground pattern 3 side by selecting the third passive element P3. It is.

As described above, in the antenna device 1 according to the present embodiment, the ground pattern 3 includes the first ground extending portion G1 extending along the second extending portion E2 from the vicinity of the feeding point FP, and the first ground extending portion. Since it has the 2nd ground extension part G2 which projected and extended between G1 from the 1st extension part E1 and element branching part E7, it is 1st extension part E1, 2nd from feeding point FP. A high-frequency current flows in a loop through the base end side of the extending part E2, the element branching part E7, the second ground extending part G2, and the first ground extending part G1, so that a resonance frequency different from that of the first element 4 is obtained. Can be generated. In addition, the stray capacitance is generated between the second ground extension part G2, the first extension part E1, the base end side of the second extension part E2, and the element branch part E7, thereby adjusting the resonance frequency. Broadband can be achieved.
Furthermore, the first element 4, the loop-like portion that generates a high-frequency current, and the ground main surface portion 3 a can be arranged side by side in one direction, and can be provided on the elongated substrate body 2. become.

Moreover, since the front-end | tip part of the 2nd ground extension part G2 is made into the wide front-end | tip part G2a extended to the 1st extension part E1 side and the element branch part E7 side, according to the width | variety of the wide front-end | tip part G2a The stray capacitance generated between the base end side of the first extending portion E1 and the second extending portion E2 and the element branching portion E7 can be adjusted.
Further, since the additional element portion E8 extending from the tip of the element branching portion E7 toward the other end side of the substrate body 2 is provided, the additional element portion E8 having an open end and the first element 4 are provided. A stray capacitance is generated in the first, and another resonance frequency can be generated.

In addition, since the antenna element AT of the dielectric antenna is connected in the middle of 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. 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.
In addition, since the passive element is connected to the base end or the middle of the second extending portion E2 or the additional element E8, each resonance frequency can be flexibly adjusted by selecting the passive element, and the complex frequency corresponding to the design condition can be adjusted. An antenna device capable of resonance can be obtained. Thus, since each resonance frequency can be flexibly adjusted in terms of the antenna configuration, the resonance frequency can be switched, and the adjustment location by a passive element or the like can be changed according to the application or device.

In addition, this invention is not limited to said each embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, in each of the above embodiments, the antenna element is provided in the second extending portion, but the antenna element is provided in the tenth extending portion or the third extending portion to shorten the element, thereby reducing the size of the entire apparatus. You may plan to make it.

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 body, 2a ... One side of a board | substrate body, 2b ... The other side of a board | substrate body, 3 ... Ground pattern, 3a ... Ground main surface part, 3b ... Ground connection part, 4 ... 1st DESCRIPTION OF SYMBOLS 1 element, 5 ... 2nd element, AT ... Antenna element, E1 ... 1st extension part, E2 ... 2nd extension part, E3 ... 3rd extension part, E4 ... 4th extension part, E5 ... 5th Extension part, E7 ... Element branch part, E8 ... Additional element part, E9 ... Ninth extension part, E10 ... Tenth extension part, E11 ... Eleventh extension part, GND ... Ground, G1 ... First ground extension Present part, G2 ... second ground extension part, P1 ... first passive element, P2 ... second passive element, P3 ... third passive element, P4 ... fourth passive element, P5 ... fifth passive element, P6 ... first 6 passive elements, FP ... feed point

Claims (7)

A rectangular and insulating substrate body, a ground pattern patterned with a metal foil on one end side of the substrate body and connected to the ground, and a first pattern patterned with metal foil on the substrate body and connected to a feeding point With elements,
The feeding point is arranged on one side of both sides extending from one end of the substrate body to the other end,
A ground main surface portion formed on one end side of the substrate body apart from the feeding point, the ground pattern;
A ground connection portion disposed from the ground main surface portion to the vicinity of the feeding point;
The first element extends from the feeding point toward the other side of the substrate body; and
A second extending portion extending from the tip of the first extending portion toward the other end of the substrate body;
An element branch extending from the middle of the second extending portion along the first extending portion toward one side of the substrate body;
A first ground extension portion connected to the ground connection portion and extending along the second extension portion from the vicinity of the feeding point;
The antenna device further comprising: a second ground extending portion that protrudes from the first ground extending portion and extends between the first extending portion and the element branching portion. The antenna device according to claim 1,
The antenna device according to claim 1, wherein a distal end portion of the second ground extending portion is a wide distal end portion extending to the first extending portion side and the element branching portion side. In the antenna device according to claim 1 or 2,
An antenna device comprising an additional element portion extending from the tip of the element branching portion toward the other end of the substrate body. In the antenna device according to any one of claims 1 to 3,
An antenna device, wherein an antenna element of a dielectric antenna is connected in the middle of the second extending portion. In the antenna device according to any one of claims 1 to 4,
A passive element is connected to the base end or the middle of the second extending portion. The antenna device according to claim 3, wherein
A passive element is connected to the base end or the middle of the additional element portion. In the antenna device according to any one of claims 1 to 6,
The substrate body has a thin plate shape extending in a strip shape,
The antenna device characterized in that the ground main surface portion extends in a band shape on one end side of the substrate body.