Composite patch antenna device

Abstract

To provide a small and thin composite patch antenna device that supports multiple frequency bands.SOLUTION: A composite patch antenna device includes a ground plate 10, a dielectric 20, a first patch element 30, a second patch element 40, and a filter portion 50. The first patch element 30 is disposed on the dielectric 20, has a power supply portion 31, and corresponds to a first frequency band. The second patch element 40 is formed in the first patch element 30 and separated from the first patch element 30 by a slit 41 of a predetermined width, shares the power supply portion 31 of the first patch element 30, and corresponds to a second frequency band higher than the first frequency band. The filter portion 50 is connected between the first patch element 30 and the second patch element 40, and attenuates signals in the second frequency band and passes signals in the first frequency band.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a composite patch antenna device, and more particularly to a small and thin composite patch antenna device compatible with multiple frequency bands. [Background technology]

[0002] Motorcycles use headsets for communication between drivers and passengers. Headsets usually use Bluetooth (registered trademark) communication, and motorcycles have recently been equipped with Bluetooth antennas. Furthermore, wireless LAN antennas are also installed so that wireless LAN communication such as Wi-Fi (registered trademark) communication can be performed with mobile information terminals such as smartphones. Bluetooth communication is in the 2.4 GHz band, and wireless LAN communication is also in the 2.4 GHz band, so they are prone to interference with each other. For this reason, for example, Patent Document 1 discloses an antenna device in which an antenna element for Bluetooth communication and an antenna element for wireless LAN communication are arranged on the same plane and a slit is provided in the ground layer to improve isolation.

[0003] Furthermore, for example, Patent Document 2 discloses a stacked patch antenna device in which planar antenna elements are provided on each layer of a multilayer substrate to accommodate multiple frequency bands, with a feeding point provided only on the planar antenna element on the top layer, and the planar antenna elements on the lower layers being excited using a non-feeding method. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2021-184593 A [Patent Document 2] JP 2003-283240 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, since wireless LAN communication uses not only the 2.4 GHz band but also the 5 GHz band, a separate antenna element compatible with the 5 GHz band is required. For example, in an example in which multiple antenna elements are arranged on the same plane as disclosed in the above-mentioned Patent Document 1, an area is required to arrange on the same plane an antenna element for Bluetooth communication in the 2.4 GHz band and an antenna element for wireless LAN communication in the 2.4 GHz band and 5 GHz band, respectively, and this inevitably results in an increase in the size of the antenna device.

[0006] In addition, in the case of a laminated patch antenna device using a multi-layer substrate as in Patent Document 2, the projection area is small, but the thickness is inevitably large. In addition, the laminated substrate structure makes it expensive. Furthermore, since the structure is excited by a non-power feeding method, it is difficult to obtain sufficient antenna characteristics.

[0007] For this reason, there has been a demand for the development of a small, thin patch antenna device that is circularly polarized so as to enable communication regardless of the orientation of the antenna relative to a motorcycle, and that is compatible with a plurality of frequency bands.

[0008] SUMMARY OF THE PRESENT EMBODIMENT In view of the above circumstances, the present invention provides a small and thin composite patch antenna device that is compatible with a plurality of frequency bands. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object of the present invention, a composite patch antenna device according to the present invention may include a ground plate, a dielectric arranged on the ground plate, a first patch element arranged on the dielectric, having a power feed portion and corresponding to a first frequency band, a second patch element formed within the first patch element and separated from the first patch element by a slit of a predetermined width, sharing the power feed portion of the first patch element, and corresponding to a second frequency band higher than the first frequency band, and a filter portion connected between the first patch element and the second patch element for attenuating signals of the second frequency band and passing signals of the first frequency band.

[0010] Here, the filter section may be connected between the first patch element and the second patch element in the vicinity of a position far from the power supply section.

[0011] Moreover, the filter section may be any section that is capable of adjusting the impedance characteristics of the first patch element by changing the connection position thereof.

[0012] The filter section may be made up of a trap coil or a low-pass filter circuit.

[0013] Moreover, the filter section may be arranged on the side where the dielectric ground plate is arranged, and may be connected between the first patch element and the second patch element via a through hole.

[0014] The filter section may also be made of a meandering pattern arranged on the side of the dielectric where the first patch element and the second patch element are arranged.

[0015] The first patch element may have a cutout portion for adjusting the impedance characteristics of the first patch element.

[0016] The second patch element may be formed to have a similar shape to the first patch element.

[0017] Furthermore, the power supply section may be a one-point or two-point power supply section.

[0018] Furthermore, the first patch element may include a third patch element that is formed within the second patch element and separated from the second patch element by a slit of a predetermined width, shares the power supply section of the first patch element, and corresponds to a third frequency band that is higher than the second frequency band; and a second filter section that is connected between the second patch element and the third patch element and attenuates signals of the third frequency and passes signals of the first frequency band and the second frequency band. Effect of the Invention

[0019] The composite patch antenna device of the present invention has the advantage of being small and thin while being compatible with a plurality of frequency bands. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic top view for explaining a composite patch antenna device of the present invention. [Diagram 2] FIG. 2 is a schematic cross-sectional side view taken along line aa-a for explaining the composite patch antenna device of the present invention. [Diagram 3] FIG. 3 is a circuit diagram for explaining a filter section of the composite patch antenna device of the present invention. [Figure 4] FIG. 4 is a schematic enlarged top view for explaining another example of the filter portion of the composite patch antenna device of the present invention. [Diagram 5] FIG. 5 is a schematic top view for explaining another example of the first patch element of the composite patch antenna device of the present invention. [Figure 6] FIG. 6 is a schematic top view for explaining an example of a composite patch antenna device of the present invention having a two-point feed section. [Figure 7] FIG. 7 is a schematic top view for explaining an example in which the composite patch antenna device of the present invention is adapted to three frequency bands. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, the embodiment of the present invention will be described with reference to the drawings. The composite patch antenna device of the present invention is compatible with a plurality of frequency bands. Specifically, it is compatible with, for example, the 2.4 GHz band for Bluetooth communication and the 5 GHz band for wireless LAN communication. However, the present invention is not limited thereto, and any frequency band that can be supported by the patch antenna may be used. FIG. 1 is a schematic top view for explaining the composite patch antenna device of the present invention. FIG. 2 is a schematic aa side cross-sectional view for explaining the composite patch antenna device of the present invention. In the figure, the parts with the same reference numerals as those in FIG. 1 represent the same objects. As shown in the figure, the composite patch antenna device of the present invention is mainly composed of a ground plate 10, a dielectric 20, a first patch element 30, a second patch element 40, and a filter section 50. The composite patch antenna device of the present invention has a circularly polarized microstrip antenna structure so that communication is possible regardless of the orientation.

[0022] The ground plate 10 serves as the conductive ground plate of the composite patch antenna device. It may be made of a uniform conductive plate. In order to connect the filter section 50 and the signal line of the coaxial cable 1 described below, a connection land separated from the ground plate 10 may be formed.

[0023] The dielectric 20 is disposed on the ground plate 10. The dielectric 20 serves as the dielectric of the composite patch antenna device, and the wavelength shortening effect is obtained by the dielectric constant of the dielectric. The dielectric 20 may be, for example, ceramics, a printed circuit board, or an air space. When the dielectric 20 is a printed circuit board, the solid pattern on the back side of the printed circuit board may be used as the ground plate 10.

[0024] The first patch element 30 corresponds to a first frequency band. Here, the first frequency band may be, for example, the 2.4 GHz band used in Bluetooth communication or wireless LAN communication. The first patch element 30 is disposed on the dielectric 20. The first patch element 30 has a power feed section 31. The power feed section 31 is connected to the connection section of the coaxial cable 1 on the back side of the dielectric 20 via a through hole 32. A resistor for connection detection or the like may be appropriately connected between the connection section of the coaxial cable 1 and the power feed section 31. In the illustrated example, the power feed section 31 is one-point power feed. The impedance characteristics can be adjusted by the offset position of the power feed section 31 from the center of the first patch element 30. In the illustrated example, the first patch element 30 is configured to generate circularly polarized waves by providing degenerate separation elements 33 at the upper right and lower left of a square pattern. However, the present invention is not limited to this, and degenerate separation elements such as cuts may be provided symmetrically in a circular pattern. That is, the shape of the first patch element 30 is not important as long as it is configured to generate a circularly polarized wave. The size of the first patch element 30 may be, for example, such that the length of one side is λ / 2 of the wavelength of the first frequency band.

[0025] The second patch element 40 corresponds to a second frequency band higher than the first frequency band. Here, the second frequency band may be, for example, the 5 GHz band used in wireless LAN communication. The second patch element 40 is formed in the first patch element 30 by a slit 41 of a predetermined width, separated from the first patch element 30. That is, the second patch element 40 is formed by separating the inside of the first patch element 30 arranged on the dielectric 20 by the slit 41. In other words, a part of the first patch element 30 is used as the second patch element 40. The second patch element 40 shares the power supply section 31 of the first patch element 30. That is, the signals of the first frequency band and the second frequency band may be appropriately separated on the unit side. In the illustrated example, the second patch element 40 is configured to generate a circularly polarized wave by providing degenerate separation elements 43 at the upper right and lower left of a rectangular pattern. Moreover, the second patch element 40 may be formed to have a similar shape to the first patch element 30. However, the present invention is not limited to this, and the shape may be changed as appropriate, for example, to adjust the antenna characteristics of the second patch element 40. The dimensions of the second patch element 40 may be, for example, such that the length of one side is λ / 2 of the wavelength of the second frequency band.

[0026] The filter section 50 attenuates signals in the second frequency band and passes signals in the first frequency band. The filter section 50 is connected between the first patch element 30 and the second patch element 40. Specifically, the filter section 50 is disposed in a slit 41 between the first patch element 30 and the second patch element 40. That is, the first patch element 30 functions as a microstrip antenna that resonates in the first frequency band together with the second patch element 40 via the filter section 50. On the other hand, since signals in the second frequency band are attenuated by the filter section 50, only the second patch element 40 functions as a microstrip antenna that resonates in the second frequency band.

[0027] As shown in the figure, the filter section 50 is connected between the first patch element 30 and the second patch element 40 near a position far from the power supply unit 31. That is, the filter section 50 is disposed at the position of the slit 41 farthest from the power supply unit 31, which is offset downward from the center of the first patch element 30. Specifically, the filter section 50 is connected near the upper left corner of the second patch element 40. This makes the impedance characteristics of both the first patch element 30 and the second patch element 40 the best. However, the present invention is not limited to this, and as long as the antenna characteristics are within an acceptable range, the filter section 50 may be connected to a position that is not too close to the power supply unit 31 from the upper left corner of the second patch element 40, which is the farthest from the power supply unit 31, such as the upper right corner. By adjusting the connection position of the filter section 50, it is possible to adjust the impedance characteristics of the first patch element 30 in particular.

[0028] 2, the filter section 50 is disposed on the side of the dielectric 20 where the ground plate 10 is disposed. The filter section 50 is connected between the first patch element 30 and the second patch element 40 via through holes 21. With this configuration, all of the parts for connecting the filter section 50 and the coaxial cable 1 are disposed on the side where the ground plate 10 is disposed, and therefore soldering is performed only on one side, improving the ease of assembly.

[0029] The ground plane 10, the dielectric 20, the first patch element, and the second patch element can be formed, for example, using a double-sided printed circuit board. That is, the first patch element 30 and the second patch element 40 may be patterned by etching.

[0030] FIG. 3 shows an example of the filter section 50. FIG. 3 is a circuit diagram for explaining the filter section of the composite patch antenna device of the present invention. FIG. 3(a) shows an example in which the filter section 50 is composed of a trap coil 51. The trap coil may be, for example, a chip inductor. FIG. 3(b) shows an example in which the filter section 50 is composed of an LC filter composed of a coil 52 and a capacitor 53. Such a low-pass filter circuit may be used. In the illustrated example, the coil 52 and the capacitor 53 are shown, but it is not necessarily necessary to provide electronic circuit components, and the filter section 50 may be configured to be an LC filter in terms of an equivalent circuit using coupling capacitance or the like. The filter section 50 configured in this manner attenuates signals in the second frequency band and passes signals in the first frequency band. The present invention is not limited to this, and any existing or future configurations of the filter section 50 can be applied as long as the filter section 50 is configured to attenuate signals in the second frequency band and pass signals in the first frequency band.

[0031] The composite patch antenna device of the present invention configured as described above operates as follows: For the first frequency band, the filter section 50 passes signals in the first frequency band, so that the entire section from the second patch element 40 connected to the power supply section 31 through the filter section 50 to the first patch element 30 functions as a microstrip antenna for the first frequency band.

[0032] On the other hand, for the second frequency band, resonance occurs at λ / 2 of the wavelength of the second frequency band using the second patch element 40 connected to the power supply unit 31. Although the filter unit 50 is connected between the first patch element 30 and the second patch element 40, the signal of the second frequency band is attenuated so that the signal does not propagate to the first patch element 30 side, and only the second patch element 40 functions as a microstrip antenna. That is, the first patch element 30 is made invisible from the second patch element 40 by the filter unit 50. Therefore, the filter unit 50 also plays a role in increasing the isolation between the first patch element 30 and the second patch element 40.

[0033] In this way, the filter section 50 acts as a trap coil that attenuates signals in the second frequency band for the second frequency band, and also acts to excite the first patch element 30 via the filter section 50 for the first frequency band.

[0034] According to the composite patch antenna device of the present invention, the second patch element 40 corresponding to the second frequency band can be arranged inside the range of the first patch element 30 corresponding to the first frequency band. That is, by using a part of the first patch element 30 as the second patch element 40, it is possible to support up to the second frequency band with only the area for the first frequency band. Therefore, since a separate area for supporting the second frequency band is not required, it is possible to reduce the size of the antenna device. Furthermore, since it is not necessary to form a laminated structure to support the second frequency band, and the thickness is the same as that of the first patch element 30 corresponding to the first frequency band, it is possible to reduce the thickness of the antenna device.

[0035] In the illustrated example described above, the filter section 50 is disposed on the side of the dielectric 20 where the ground plate 10 is disposed. However, the present invention is not limited to this. FIG. 4 is a schematic top view enlarged for explaining another example of the filter section of the composite patch antenna device of the present invention. In the figure, the parts with the same reference numerals as in FIG. 1 represent the same objects. In FIG. 4, only the periphery of the filter section 50 is shown, and the other parts are omitted. As shown in the figure, the filter section 50 of the composite patch antenna device of the present invention is disposed on the side of the dielectric 20 where the first patch element 30 and the second patch element 40 are disposed. The filter section 50 is made of a meander pattern 52. If the filter section 50 is made of a meander pattern 52, it can be patterned by etching at the same time as the first patch element 30 and the second patch element 40. Therefore, there is no need to solder the filter section 50, which further improves the ease of assembly and reduces costs.

[0036] The first patch element of the composite patch antenna device of the present invention may be deformed in shape to adjust the impedance as appropriate. FIG. 5 is a schematic top view for explaining another example of the first patch element of the composite patch antenna device of the present invention. In the figure, the parts with the same reference numerals as those in FIG. 1 represent the same objects. As shown in the figure, the first patch element 30 may have a cutout portion 34 for adjusting the impedance characteristics of the first patch element 30. By appropriately adjusting the width and length of the cutout portion 34, the impedance characteristics of the first patch element 30 can be adjusted. That is, the impedance characteristics can be adjusted by using the cutout portion 34 together with the connection position of the filter portion 50. In the illustrated example, an example in which the cutout portion 34 is provided only in the first patch element 30 is shown, but the present invention is not limited to this, and the cutout portion may be provided in the second patch element 40.

[0037] In the illustrated examples so far, an example of a composite patch antenna device with a single-point feeder has been shown. However, the present invention is not limited to this. FIG. 6 is a schematic top view for explaining an example of a composite patch antenna device of the present invention with a two-point feeder. In the figure, parts with the same reference numerals as in FIG. 1 represent the same objects. As shown in the figure, the feeder 31 of the composite patch antenna device of the present invention may be composed of a first feeder 31a and a second feeder 31b. Note that since circular polarization is generated by two-point feeder, no degenerate separation element is required.

[0038] In the case of such a two-point feeding, the filter section 50 is composed of a filter section 50a and a filter section 50b. The filter section 50 (50a, 50b) is connected between the first patch element 30 and the second patch element 40 in the vicinity of a position far from the feeding section 31 (31a, 31b), as in the case of a single-point feeding.

[0039] In this way, the feeder 31 of the composite patch antenna device of the present invention may be a single-point feeder or a dual-point feeder. A dual-point feeder is particularly effective when it is desired to widen the axial ratio for the second frequency band.

[0040] Furthermore, the composite patch antenna device of the present invention can be adapted to more frequency bands. FIG. 7 is a schematic top view for explaining an example in which the composite patch antenna device of the present invention is adapted to three frequency bands. In the figure, the parts with the same reference numerals as in FIG. 1 represent the same objects. As shown in the figure, this example has a third patch element 60. The third patch element 60 corresponds to a third frequency band higher than the second frequency band. The third patch element 60 is formed in the second patch element 40 by a second slit 61 of a predetermined width, separated from the second patch element 40. That is, the third patch element 60 is formed by separating the inner side of the second patch element 40 arranged on the dielectric 20 by the second slit 61. In other words, a part of the second patch element 40 is used as the third patch element 60. The third patch element 60 shares the power supply section 31 of the first patch element 30. That is, the signals of the first frequency band, the second frequency band, and the third frequency band may be appropriately separated on the unit side. In the illustrated example, the third patch element 60 is configured to generate circularly polarized waves by providing degenerate separation elements 63 at the upper right and lower left of a rectangular pattern. The third patch element 60 may be formed to have a similar shape to the first patch element 30 and the second patch element 40. However, the present invention is not limited to this, and the shape of the third patch element 60 may be changed as appropriate, for example, to adjust the antenna characteristics of the third patch element 60. The dimensions of the third patch element 60 may be, for example, a height of λ / 2 of the wavelength of the third frequency band.

[0041] And, a second filter section 55 is provided. The second filter section 55 attenuates signals in the third frequency band and passes signals in the first and second frequency bands. The second filter section 55 is connected between the second patch element 40 and the third patch element 60. Specifically, the second filter section 55 is disposed in a second slit 61 between the second patch element 40 and the third patch element 60. That is, the second patch element 40 functions as a microstrip antenna that resonates in the second frequency band together with the third patch element 60 via the second filter section 55. On the other hand, since the signals in the third frequency band are attenuated by the second filter section 55, only the third patch element 60 functions as a microstrip antenna that resonates in the third frequency band.

[0042] In the example shown in the figure, a filter that can handle three frequency bands is shown, but the present invention is not limited to this. It is also possible to separate the inner element with a slit and provide a filter section to make the filter compatible with more frequency bands.

[0043] In this way, according to the present invention, it is possible to provide a small and thin composite patch antenna device that is compatible with a plurality of frequency bands.

[0044] The composite patch antenna device of the present invention is not limited to the above-mentioned illustrated examples, and it is needless to say that various modifications can be made without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0045] 1 Coaxial Cable 10 Ground plate 20 Dielectrics 21 Through Hole 30 First patch element 31 Power supply unit 31a Power supply unit 31b Power supply unit 32 through hole 33 Degenerate separation element 34 Cutout 40 Second patch element 41 Slit 43 Degenerate Separation Element 50 Filter section 50a Filter section 50b Filter section 50 Filter section 51 Trap coil 52 Coil 52 Meander Pattern 53 Capacitor 55 Second filter section 60 3rd patch element 61 Second Slit 63 Degenerate Separation Element

Claims

1. A composite patch antenna device compatible with a plurality of frequency bands, the composite patch antenna device comprising: A ground plate and a dielectric disposed on the ground plane; a first patch element disposed on the dielectric body, the first patch element having a feed portion and corresponding to a first frequency band; a second patch element that is formed in the first patch element and separated from the first patch element by a slit of a predetermined width, shares a power supply part of the first patch element, and corresponds to a second frequency band higher than the first frequency band; a filter section connected between the first patch element and the second patch element, for attenuating signals in a second frequency band and passing signals in a first frequency band; A composite patch antenna device comprising:

2. 2. The composite patch antenna device according to claim 1, wherein said filter section is connected between the first patch element and the second patch element in the vicinity of a position far from a power feed section.

3. 2. The composite patch antenna device according to claim 1, wherein said filter section is capable of adjusting the impedance characteristics of said first patch element by changing the connection position thereof.

4. 2. The composite patch antenna device according to claim 1, wherein said filter section comprises a trap coil or a low-pass filter circuit.

5. 2. The composite patch antenna device according to claim 1, wherein the filter section is arranged on the side where a dielectric ground plate is arranged, and is connected between the first patch element and the second patch element via a through hole.

6. 2. The composite patch antenna device according to claim 1, wherein the filter section is formed of a meandering pattern arranged on the side of the dielectric on which the first patch element and the second patch element are arranged.

7. 2. The composite patch antenna device according to claim 1, wherein the first patch element has a notch for adjusting the impedance characteristics of the first patch element.

8. 2. The composite patch antenna device according to claim 1, wherein the second patch element is formed to have a shape similar to that of the first patch element.

9. 2. The composite patch antenna device according to claim 1, wherein said feed portion is a single-point feed or a dual-point feed.

10. 10. The composite patch antenna device according to claim 1, further comprising: a third patch element that is formed in the second patch element and separated from the second patch element by a slit of a predetermined width, shares the power supply part of the first patch element, and corresponds to a third frequency band higher than the second frequency band; a second filter section connected between the second patch element and the third patch element, which attenuates a signal of a third frequency and passes signals of the first frequency band and the second frequency band; A composite patch antenna device comprising:

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