JP2008092280A - Antenna device - Google Patents

Abstract

An antenna device is provided that is small and light, has low device cost, and can ensure sufficient capacitance.
A dielectric substrate, an antenna element made of a metal plate disposed at a predetermined interval from the dielectric substrate, and a plurality of antenna elements standing from the antenna element toward the dielectric substrate. The leg piece 6 and the chip capacitor 4 electrically connected to the leg piece 6 and the dielectric substrate 2 are provided.
[Selection] Figure 2

Description

  The present invention relates to an antenna device, and more particularly to a planar small antenna device used for a global positioning system (GPS) antenna or the like.

With the development of small communication devices such as mobile communication devices in recent years (for example, GPS-type car navigation devices, portable navigation devices, satellite wave receivers, etc.), the antenna devices used in these devices have been downsized. High performance is required.
In this respect, a planar antenna device (for example, a circularly polarized patch antenna) among antenna devices is advantageous in that it is thin and small in size and relatively easy to integrate with a semiconductor circuit. It is widely applied as an antenna for small communication equipment.

  As such a planar antenna device, for example, one having a configuration including a substrate formed of a high dielectric material such as ceramics, a radiation element provided on the surface of the substrate, and a circuit board is known. (For example, refer to Patent Document 1, Patent Document 2, and Patent Document 3).

In the antenna device having such a configuration, the capacitance of the antenna can be ensured by the high dielectric material, so that the resonance frequency is lowered and the radiation conductor plate can be reduced in size.
JP 2001-339232 A JP 2001-339233 A JP 2001-339234 A

  However, high dielectrics such as ceramics are heavy and expensive. For this reason, as described in Patent Document 1, when a high dielectric such as ceramics is mounted on a small planar antenna device, there is a problem that the entire device becomes heavy and costs increase.

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide an antenna device that is small and lightweight, has a low device cost, and can ensure a sufficient capacitance. To do.

In order to solve the above problem, an antenna device according to claim 1 is provided.
A dielectric substrate;
An antenna element made of a metal plate disposed at a predetermined interval from the dielectric substrate;
A plurality of leg pieces standing from the antenna element toward the dielectric substrate;
And a chip capacitor electrically connected to the leg piece and the dielectric substrate.

  According to the first aspect of the present invention, the dielectric substrate and the leg pieces of the antenna element are electrically connected via the chip capacitor.

The invention according to claim 2 is the antenna device according to claim 1,
The leg pieces are arranged point-symmetrically with respect to the center of the antenna element, and the chip capacitor is provided corresponding to each leg piece.

  According to the second aspect of the present invention, a chip capacitor is provided corresponding to each of the leg pieces arranged point-symmetrically with respect to the center of the antenna element, and each leg piece is connected to the dielectric via the chip capacitor. It is electrically connected to the substrate.

The invention according to claim 3 is the antenna device according to claim 1 or 2,
On the dielectric substrate, a conductor layer in which a circuit is formed, and a conductive portion insulated from the conductor layer are provided,
One end of the leg piece is in contact with the conducting part,
The chip capacitor is provided so as to be in contact with both one end of the conducting portion and the conductor layer.

  According to the third aspect of the present invention, the one end of the leg piece is in contact with the conducting portion on the dielectric substrate, and the leg piece is in contact with both the one end of the conducting portion and the conductor layer. It is electrically connected to the conductor layer through the provided chip capacitor.

According to a fourth aspect of the present invention, in the antenna device according to any one of the first to third aspects,
An insulating portion is provided between the conductive portion of the dielectric substrate and the conductor layer,
The antenna device according to claim 1, wherein the conducting portion is surrounded by the insulating portion.

  According to the fourth aspect of the present invention, the conductive portion and the conductor layer of the dielectric substrate are insulated by the insulating portion.

  According to the first aspect of the present invention, since the antenna device is constituted by the antenna element and the dielectric substrate without using a high dielectric material such as ceramics, the number of parts is small, and the device is reduced in size and weight. Can be realized, and the apparatus cost can be reduced.

  Further, since the dielectric substrate and the leg pieces of the antenna element are connected via the chip capacitor, a sufficient electrostatic capacity can be secured without using a high dielectric such as ceramics.

  According to the invention described in claim 2, since the leg pieces are arranged point-symmetrically with respect to the center of the antenna element, the performance as an antenna is stabilized. In addition, since chip capacitors are provided for each leg piece, sufficient capacitance can be ensured without using a high-dielectric material such as ceramics, and the chip capacitors are arranged at symmetrical positions. By doing so, an effect that the performance as an antenna is stabilized is exhibited.

  According to the third aspect of the present invention, since the leg pieces of the antenna element are electrically connected to the conductor layer of the dielectric substrate via the chip capacitor, it is not necessary to use a high dielectric such as ceramics. The effect that a sufficient electrostatic capacity can be secured is achieved.

  According to the fourth aspect of the invention, since the conductive portion of the dielectric substrate and the conductor layer are separated by the insulating portion, there is an effect that the conductive portion and the conductive layer can be reliably insulated.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 4. However, the scope of the invention is not limited to the illustrated examples.

  FIG. 1 is a perspective view of an antenna device 1 according to the present invention. FIG. 2 is a bottom view of the antenna device 1 shown in FIG. 3 is an enlarged view of a part of the upper surface of the dielectric substrate of the antenna device shown in FIG. 1, and FIG. 4 is an enlarged view of a part of the lower surface of the dielectric substrate of the antenna device shown in FIG.

  As shown in FIGS. 1 and 2, the antenna device 1 includes a dielectric substrate 2 having conductor layers 21 such as copper thin films on both surfaces. The dielectric substrate 2 is formed in a quadrangular shape, and four through holes 22 are provided in the vicinity of each corner of the dielectric substrate 2. In addition, an insertion hole 23 for inserting a power supply pin 3 described later is provided at a position slightly displaced from the center of the dielectric substrate 2.

  As shown in FIG. 3, an insulating portion 24 is provided on the periphery of the through hole 22 and the insertion hole 23 on one surface of the dielectric substrate 2 (upper surface in FIG. 1; hereinafter simply referred to as “upper surface”). The through hole 22 and the insertion hole 23 are insulated from the conductor layer 21. On the other hand, as shown in FIGS. 2 and 4, on the other surface of the dielectric substrate 2 (the lower surface in FIG. 1; hereinafter, simply referred to as “lower surface”), a conduction portion 25 is formed at the periphery of the through hole 22. Is provided so as to surround. An insulating portion 26 is provided on the periphery of the conduction portion 25 and the periphery of the insertion hole 23 so as to surround the conduction portion 25 and the insertion hole 23. Further, the entire periphery of the insulating portion 26 is covered with a conductor layer 27, and a circuit element such as a low noise amplifier (LNA) (not shown) is mounted on the conductor layer 27.

As shown in FIGS. 2 and 4, chip capacitors 4 as lumped constant elements are provided on the lower surface of the dielectric substrate 2 so as to be in contact with one end of each conductive portion 25. Each chip capacitor 4 is arranged so that one end is in contact with the conducting portion 25 and the other end is in contact with the conductor layer 27 with the insulating portion 26 interposed therebetween.
The chip capacitor 4 is, for example, a multilayer ceramic chip capacitor configured by sandwiching a conductor such as ceramics with a metal plate or the like. However, the chip capacitor 4 can be applied as long as it is a small and light capacitor, and the configuration is not particularly limited. Further, the chip capacitor 4 may be disposed at a position where one end is in contact with the conducting portion 25 and the other end is in contact with the conductor layer 27 with the insulating portion 26 interposed therebetween, and the position is not limited to the illustrated example.

  Of the insulating portions 24 provided on the upper surface of the dielectric substrate 2, the longitudinal size of the insulating portion 24 provided on the periphery of the through hole 22 and the conduction portion 25 provided on the lower surface of the dielectric substrate 2. The size in the longitudinal direction is substantially the same, and the insulating portion 24 provided on the periphery of the through hole 22 faces the conducting portion 25. Thereby, the conduction | electrical_connection part 25 and the conductor layer 21 of an upper surface are not made to oppose.

  In addition, the feeding pin 3 is inserted into the insertion hole 23 of the dielectric substrate 2 so as to penetrate the dielectric substrate 2. The lower end portion of the power feed pin 3 (the end portion protruding from the lower surface side of the dielectric substrate 2) is connected to a central conductor of a coaxial cable (not shown), and the external receiving circuit is connected to the antenna device 1 via the coaxial cable. A signal is sent to.

  Above the upper surface side of the dielectric substrate 2, a flat antenna element 5 disposed in parallel with the dielectric substrate 2 with a predetermined interval is provided. The antenna element 5 is composed of a rectangular metal plate (for example, a copper plate) having a size smaller than that of the dielectric substrate 2.

In the vicinity of each corner of the antenna element 5, metal flat leg pieces 6 are erected toward the dielectric substrate 2, and the leg pieces 6 are substantially point-symmetric with respect to the center of the antenna element 5. Be placed. The leg piece 6 is formed integrally with the antenna element 5 by bending a part of the antenna element 5, for example.
Note that the leg pieces 6 are only required to be substantially point-symmetric with respect to the center of the antenna element 5, and the number, shape, and the like of the leg pieces 6 are not limited to those exemplified here.

  The ends of the plurality of leg pieces 6 on the dielectric substrate 2 side are inserted into through holes 22 provided in the vicinity of each corner of the dielectric substrate 2, as shown in FIGS. It does not conduct with the dielectric substrate 2 and penetrates from the upper surface (surface facing the antenna element 5) side to the lower surface side of the dielectric substrate 2.

  As described above, the periphery of the through hole 22 is surrounded by the conductive portion 25 on the lower surface side of the dielectric substrate 2, and the portion of the leg piece 6 protruding from the lower surface side of the dielectric substrate 2 (hereinafter, “fixing portion 61”). Is in contact with the conductive portion 25 and is fixed by solder or the like. In addition, the fixing | fixed part 61 should just be fixed so that it may not fall out from the through-hole 22, and the method of fixing the fixing | fixed part 61 is not limited to solder.

  Further, as described above, the chip capacitor 4 is provided at a position in contact with both one end portion of each conductive portion 25 and the conductor layer 27, and the fixing portion 61 of each leg piece 6 is connected to the conductive portion 25. By being fixed in contact with the conductive portion 25, the conductive layer 27 is electrically connected to the conductor layer 27 of the dielectric substrate 2 through the chip capacitor 4 connected to the conductive portion 25.

  A feeding point 51 is provided at a position slightly displaced from the center of the antenna element 5, and the feeding point 51 is connected to the upper end portion of the feeding pin 3 that penetrates the dielectric substrate 2 (connected to the coaxial cable). The end on the non-side is soldered.

  Next, the operation of this embodiment will be described.

  In the antenna device 1 in the present embodiment, the end portions of the plurality of leg pieces 6 formed integrally with the antenna element 5 are respectively inserted into the through holes 22 provided in the dielectric substrate 2, and the protruding portions ( The fixing portion 61) is fixed by soldering to the conduction portion 25 provided on the lower surface of the dielectric substrate 2. As a result, the fixing portion 61 is fixed to the dielectric substrate 2 without coming off, and each chip capacitor 4 provided at a position in contact with one end portion of each conduction portion 25 and the conductor layer 27 is used for each. The fixing portion 61 of the leg piece 6 is electrically connected to the conductor layer 27 of the dielectric substrate 2.

  In addition, the feeding pin 3 whose one end is connected to the central conductor of the coaxial cable is inserted into the insertion hole 23 of the dielectric substrate 2, and the other end (upper end) of the feeding pin 3 is the feeding point of the antenna element 5. Solder to 4. As a result, the feed pin 3 penetrates the dielectric substrate 2 without being electrically connected to the dielectric substrate 2 and is connected to the antenna element 5.

When a predetermined high-frequency signal is supplied to the antenna element 5 through the feed pin 3, an electric field is formed and circularly polarized radio waves are radiated from the antenna element 5.
On the other hand, when a signal radio wave is received by the antenna element 5, this electrical signal is output to an external receiving circuit via an LNA circuit, a coaxial cable, or the like.

  As described above, according to the present embodiment, the antenna device 1 includes the antenna element 5 formed of a metal plate such as a copper plate and the dielectric substrate 2, and is formed of a high dielectric such as ceramics. It does not have a substrate. For this reason, the number of parts is small, the weight of the entire apparatus can be reduced, and the apparatus can be configured without using ceramics, which is a relatively expensive material, and thus the apparatus cost can be reduced.

Further, in the present embodiment, the fixing portion 61 of the leg piece 6 and the dielectric substrate 2 are electrically connected via the chip capacitor 4, so that the substrate is enlarged or formed of a high dielectric such as ceramics. A large capacitance can be easily secured without providing a substrate or the like, and the apparatus can be reduced in size and weight.
Further, by providing the chip capacitor 4, the capacitance value can be easily adjusted.

  Since the leg pieces 6 are arranged point-symmetrically with respect to the center of the antenna element 5, the performance as an antenna is stabilized. Further, since the chip capacitors 4 are provided corresponding to the respective leg pieces 6, it is possible to ensure a sufficient capacitance without using a high dielectric such as ceramics, and the chip capacitors 6 are symmetrical. The performance as an antenna is stabilized by being arranged in the position.

  In the present embodiment, the chip capacitor 4 is disposed on the lower surface of the dielectric substrate 2. However, the chip capacitor 4 may be disposed on the upper surface of the dielectric substrate 2 (the surface facing the antenna element 5). . In this case, each chip capacitor 4 may be provided at a position where one end is in contact with the leg piece 6 and the other end is in contact with the conductor layer 21 with the insulating portion 24 interposed therebetween, and the arrangement thereof is not particularly limited. .

  Further, by adjusting the capacitance of the chip capacitor 4, the size reduction ratio of the antenna device 1 can be adjusted. However, as the capacity of the chip capacitor 4 increases, the antenna characteristic (gain) decreases. Therefore, the capacity of the chip capacitor 4 is determined in relation to the required antenna characteristics (gain).

  In addition, it is needless to say that the present invention is not limited to the above embodiment and can be modified as appropriate.

It is a perspective view which shows the antenna device which concerns on this embodiment. It is a bottom view which shows the antenna apparatus shown in FIG. It is the figure which expanded a part of upper surface of the dielectric substrate of the antenna apparatus shown in FIG. It is the figure which expanded a part of lower surface of the dielectric substrate of the antenna apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna apparatus 2 Dielectric board | substrate 3 Feeding pin 4 Chip capacitor 5 Antenna element 6 Leg piece 21 Conductor layer 22 Through-hole 23 Insertion hole 24 Insulation part 25 Conductive part 26 Insulation part 27 Conductive layer 51 Feeding point 61 Fixing part

Claims (4)

A dielectric substrate;
An antenna element made of a metal plate disposed at a predetermined interval from the dielectric substrate;
A plurality of leg pieces standing from the antenna element toward the dielectric substrate;
An antenna device comprising: a chip capacitor electrically connected to the leg piece and the dielectric substrate.   The antenna device according to claim 1, wherein the leg pieces are arranged point-symmetrically with respect to a center of the antenna element, and the chip capacitor is provided corresponding to each leg piece. On the dielectric substrate, a conductor layer in which a circuit is formed, and a conductive portion insulated from the conductor layer are provided,
One end of the leg piece is in contact with the conducting part,
The antenna device according to claim 1, wherein the chip capacitor is provided so as to be in contact with both one end portion of the conducting portion and the conductor layer. An insulating part is provided between the conductive part and the conductive layer of the dielectric substrate,
The antenna device according to any one of claims 1 to 3, wherein the conductive portion is surrounded by the insulating portion.

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