JP2005124056A - Patch antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a patch antenna which is adaptive to a plurality of frequency bands, miniaturized while securing desired antenna characteristics and is easily made low-cost. <P>SOLUTION: The patch antenna 21 is provided with two kinds of patch electrodes 23, 24 arranged side by side on the top surface of a dielectric substrate 22, a ground electrode 25 provided on the bottom surface of the dielectric substrate 22, feeding pins 27, 28 connected to feeding points of the patch electrodes 23, 24, respectively and a group of through-holes 26 provided between the patch electrodes 23, 24 and penetrating the dielectric substrate 22. The patch antenna 21 is loaded on a circuit board 30, the feeding pins 27, 28 are connected to an antenna circuit 32 and the group of through-holes 26 are connected to a ground conductor part 31. Wherein, the group of through-holes 26 are for assuring isolation by guiding an electric field between the patch electrodes 23, 24 and may be metal pins, etc. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a small patch antenna including a plurality of patch electrodes corresponding to a plurality of frequency bands.

  Recently, an in-vehicle patch antenna has been proposed that unitizes a GPS (global positioning system) antenna with a resonance frequency of 1.5 GHz and an ETC (automatic toll collection system) antenna with a resonance frequency of 5.8 GHz. Has been. Since the GPS antenna and the ETC antenna have greatly different resonance frequencies, the patch electrodes of the two are considerably different in size and shape.

  FIG. 3 is a perspective view showing a conventional example of a patch antenna having two types of patch electrodes having different resonance frequencies. In the patch antenna 1 shown in the figure, two types of patch electrodes 2 and 3 having different sizes and shapes are provided on the top surfaces of different dielectric substrates 4 and 5, respectively. That is, the patch electrode 2 is provided on the top surface of the dielectric substrate 4, the patch electrode 3 is provided on the top surface of the dielectric substrate 5, and a ground electrode (not shown) is provided on the bottom surface of each dielectric substrate 4, 5. Is provided. The pair of dielectric bases 4 and 5 are arranged in parallel at predetermined positions on the circuit board 8, and one end sides of the power supply pins 6 and 7 are connected to the power supply points of the patch electrodes 2 and 3, respectively. 2 and 3 are individually fed. A ground conductor portion 9 is provided on almost the entire surface of the circuit board 8 on which the dielectric substrates 4 and 5 are mounted. On the lower surface side of the circuit board 8, an antenna circuit (not shown) including a filter unit, an amplifier unit, and the like is disposed, and the other end side of each of the feed pins 6 and 7 is connected to the antenna circuit.

In addition, a patch antenna having a configuration in which two types of patch electrodes having different resonance frequencies are arranged side by side on the top surface of the same dielectric substrate has been proposed (for example, see Patent Document 1). FIG. 4 is a perspective view showing a conventional example of this type of patch antenna. In the patch antenna 11 shown in the figure, two types of patch electrodes 12 and 13 having different sizes and shapes are disposed on the top surface of a common dielectric substrate 14, and the bottom surface of the dielectric substrate 14 is almost the entire surface. A ground electrode (not shown) is provided. One end side of each of the feed pins 15 and 16 is connected to the feed point of each patch electrode 12 and 13, and the other end side of each of the feed pins 15 and 16 is a diagram of the circuit board 18 on which the patch antenna 11 is mounted. It is connected to an antenna circuit (not shown). A ground conductor portion 19 is provided on almost the entire surface of the circuit board 18 on the upper surface side.
JP 2001-94336 A (page 4, FIG. 4)

  In the conventional patch antenna 1 shown in FIG. 3, two types of patch electrodes 2 and 3 having different resonance frequencies are provided on separate dielectric bases 4 and 5, and the dielectric bases 4 and 5 are arranged on a circuit board 8. Since it is to be mounted, it is possible to save space by arranging the dielectric substrates 4 and 5 close to each other. However, this is because the size and shape of the dielectric substrates 4 and 5 made of ceramic or the like are different, so that the mold cost is increased, and the assembly cost is increased due to the large number of parts, resulting in high cost. There was a problem of becoming a patch antenna.

  On the other hand, the conventional patch antenna 11 shown in FIG. 4 has two types of patch electrodes 12 and 13 having different resonance frequencies provided on the top surface of the common dielectric substrate 14, so that the number of parts is small and the gold There is an advantage that mold costs and assembly costs can be reduced. However, in this case, unless the two types of patch electrodes 12 and 13 are sufficiently separated from each other to ensure isolation, the electric field generated by one patch electrode and the electric field generated by the other patch electrode interfere with each other. Since the antenna characteristics are liable to be deteriorated, a large dielectric base 14 having a wide top surface is required, and therefore there is a problem that it is difficult to reduce the size of the patch antenna.

  The present invention has been made in view of the actual situation of the prior art, and an object of the present invention is to be able to deal with a plurality of frequency bands, to achieve a desired antenna characteristic, to be downsized, and to easily reduce the cost. Is to provide a simple patch antenna.

  In order to achieve the above-described object, in the patch antenna of the present invention, a dielectric substrate made of a dielectric material, a plurality of patch electrodes arranged in parallel on the top surface of the dielectric substrate, and a bottom surface of the dielectric substrate. A ground electrode provided, a plurality of power supply means for individually supplying power to the plurality of patch electrodes, and an electric field induction means provided between the plurality of patch electrodes and penetrating the dielectric substrate, It was mounted on a circuit board having a ground conductor part on at least one side. Here, as the electric field induction means penetrating the dielectric substrate, a plurality of through holes and metal pins connected to the ground conductor portion of the circuit board are preferable, but air holes (cavities) may also be used.

  The patch antenna configured in this manner is such that a plurality of patch electrodes are arranged on the top surface of a common dielectric substrate and each patch electrode is individually fed. Electric field induction means (a plurality of through holes, metal pins, etc.) penetrating the substrate are provided, and an electric field between the patch electrodes can be induced to the electric field induction means. The risk of causing interference is reduced, and as a result, it is easy to ensure isolation without separating the plurality of patch electrodes from each other. That is, since it is not necessary to increase the size of the dielectric substrate in order to ensure desired antenna characteristics, the patch antenna can be easily reduced in size. In addition, since this patch antenna has a common dielectric base, the number of parts is small, so that the die cost and assembly cost can be reduced, and the cost can be easily reduced.

  In the patch antenna configured as described above, when the plurality of patch electrodes are a pair of patch electrodes having different resonance frequencies, a plurality of through-holes or Electric field induction means can be obtained by interspersing metal pins and the like. In this case, for example, one patch electrode can be used for GPS and the other patch electrode can be used for a smaller ETC.

  The patch antenna according to the present invention includes a plurality of patch electrodes that are individually fed to the top surface of a common dielectric substrate, and a through hole or a metal pin that penetrates the dielectric substrate between the plurality of patch electrodes. The electric field induction means such as the above is provided, and the electric field generated by each patch electrode during power feeding is less likely to cause interference, so that it is easy to ensure isolation even if the plurality of patch electrodes are not greatly separated from each other. Therefore, this patch antenna not only facilitates cost reduction by reducing the die cost and assembly cost due to the common use of the dielectric substrate, but also enlarges the dielectric substrate to ensure the desired antenna characteristics. Since it is not necessary, it is easy to reduce the size.

  An embodiment of the invention will be described with reference to the drawings. FIG. 1 is a perspective view of a patch antenna according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the patch antenna.

  The patch antenna 21 shown in these drawings is provided on almost the entire surface of a dielectric substrate 22 made of ceramic or the like, patch electrodes 23 and 24 disposed on the top surface of the dielectric substrate 22, and the bottom surface of the dielectric substrate 22. The ground electrode 25, the plurality of through holes 26 penetrating the dielectric substrate 22 at almost the midpoint between the patch electrodes 23 and 24, and the dielectric material soldered to the feeding points of the patch electrodes 23 and 24, respectively. It is constituted by power supply pins 27 and 28 penetrating the base 22. Here, one patch electrode 23 is a radiation conductor for GPS, the other patch electrode 24 is a radiation conductor for ETC smaller than that, and the patch electrodes 23 and 24 have a predetermined interval. It is installed side by side. The plurality of through holes 26 are all kept in contact with the ground electrode 25.

  As shown in FIG. 2, the patch antenna 21 is mounted and fixed on a circuit board 30 using an insulating double-sided adhesive tape 29. A ground conductor portion 31 is provided on almost the entire upper surface side and a part of the lower surface side of the circuit board 30, and an antenna circuit 32 including a filter unit and an amplifying unit is disposed on the lower surface side of the circuit board 30. It is installed. Since the lower end portions of the power feeding pins 27 and 28 are connected to the antenna circuit 32, the patch electrodes 23 and 24 of the patch antenna 21 are individually fed. A plurality of through holes 26 located between the patch electrodes 23 and 24 and penetrating the dielectric substrate 22 penetrate the circuit board 30 and are soldered to the ground conductor portion 31 on the lower surface side.

  In the patch antenna 21 described above, two types of patch electrodes 23 and 24 are arranged on the top surface of a common dielectric substrate 22 and the patch electrodes 23 and 24 are individually fed. A plurality of through holes 26 penetrating the dielectric substrate 22 are provided along an appropriate boundary line between the patch electrodes 23 and 24, and the group of these through holes 26 is a kind of shield function for inducing an electric field between the patch electrodes 23 and 24. Therefore, there is little risk of interference between the electric fields generated by the patch electrodes 23 and 24 during power feeding. That is, in the patch antenna 21, by providing the through-hole 26 group, it is easy to ensure isolation without greatly separating the two types of patch electrodes 23 and 24 from each other. Therefore, in the case of the patch antenna 21, it is not necessary to increase the size of the dielectric base 22 in order to correspond to different frequency bands for GPS and ETC, and the size reduction is realized while ensuring desired antenna characteristics. . In addition, since the patch antenna 21 has a common GPS and ETC dielectric substrate 22, the number of parts is small, and the die cost and assembly cost can be reduced, thereby making it easy to reduce the cost.

  The means for inducing the electric field between the patch electrodes 23 and 24 is not limited to the group of the through holes 26, and for example, penetrates the dielectric substrate 22 along an appropriate boundary line between the patch electrodes 23 and 24. Even if a plurality of metal pins are provided and these metal pins are connected to the ground conductor portion 31, the same effect can be obtained. Further, even if an air hole (cavity) having no internal conductor is provided in place of the through hole 26 group, the electric field between the patch electrodes 23 and 24 can be induced to some extent, so that isolation can be ensured. There is an effect of both miniaturization.

1 is a perspective view of a patch antenna according to an embodiment of the present invention. It is sectional drawing of this patch antenna. It is a perspective view which shows a prior art example. It is a perspective view which shows another prior art example.

Explanation of symbols

21 Patch antenna 22 Dielectric substrate 23, 24 Patch electrode 25 Ground electrode 26 Through hole (electric field induction means)
27, 28 Feeding pin 29 Double-sided adhesive tape 30 Circuit board 31 Ground conductor 32 Antenna circuit

Claims (5)

  A dielectric substrate made of a dielectric material, a plurality of patch electrodes arranged side by side on the top surface of the dielectric substrate, a ground electrode provided on the bottom surface of the dielectric substrate, and the plurality of patch electrodes A plurality of power supply means for individually supplying power and an electric field induction means provided between the plurality of patch electrodes and penetrating the dielectric substrate, and mounted on a circuit board having a ground conductor portion on at least one side This is a patch antenna.   2. The patch antenna according to claim 1, wherein the electric field induction means is a plurality of through holes connected to the ground conductor portion.   2. The patch antenna according to claim 1, wherein the electric field induction means is a plurality of metal pins connected to the ground conductor portion.   2. The patch antenna according to claim 1, wherein the electric field induction means is a plurality of air holes. 5. The patch antenna according to claim 1, wherein the plurality of patch electrodes are a pair of patch electrodes having different resonance frequencies.

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