Antenna elements and antenna devices

Abstract

To provide an antenna element reduced in size and in weight in comparison with a commonly-used patch antenna.SOLUTION: An antennal element 20 comprises an upper conductor 201, lower conductors 203, leg parts 205, and a power supply part 207. In the upper conductor 201 are formed opening parts 22. The upper conductor 201 has a central part 211, annular parts 213 and connection parts 215. The annular parts 213 are positioned away from the central part 211 and surround the central part 211 seamlessly. The opening parts 22 are positioned between the central part 211 and the annular parts 213 in a planar view. The connection parts 215 each connect the central part 211 to the annular parts 213. The leg parts 205 are extended from the annular parts 213. The lower conductors 203 are arranged away from the upper conductor 201 in a vertical direction and are connected to the leg parts 205. The power supply part 207 is extended from the upper conductor 201.SELECTED DRAWING: Figure 1

Description

Technical Field

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[0001] The present invention relates to an antenna element and an antenna device including the same.

Background Art

[0002] As a general patch antenna, for example, a patch antenna including a ceramic substrate disclosed in Patent Document 1 is known.

[0003] Referring to FIG. 11, a patch antenna 90 described in Patent Document 1 includes an antenna base substrate 92, a patch element 94 formed on the surface thereof, and two feeding conductors 96.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] ​​​​​​​​​​​​​​​ The annular portion is located away from the central portion and surrounds the central portion without any breaks. The aforementioned opening is located between the central portion and the annular portion in a plan view. Each of the aforementioned connecting parts connects the central part and the annular part. The at least one leg extends from the annular portion, The at least one lower conductor is separated from the upper conductor in the vertical direction and is connected to the at least one leg. The at least one power supply unit extends from the upper conductor. Provides antenna elements.

[0007] Furthermore, the present invention provides a second antenna element, which is the first antenna element, The aforementioned at least one power supply unit comprises two power supply units, The two imaginary lines connecting the center of the central section and the two power supply sections form a 90-degree angle in a plan view. Provides antenna elements.

[0008] Furthermore, the present invention provides a third antenna element, which is the first antenna element, The aforementioned at least one lower conductor comprises four lower conductors, The aforementioned at least one leg comprises four legs, The at least one lower conductor and the at least one leg are connected in a one-to-one relationship. Provides antenna elements.

[0009] Furthermore, the present invention provides a fourth antenna element, which is the first antenna element, The upper conductor, the at least one lower conductor, the at least one leg, and the at least one power supply unit are mounted on a support made of resin. Provides antenna elements.

[0010] Further, the present invention provides, as a fifth antenna element, a fourth antenna element, wherein a plurality of recesses recessed downward in the vertical direction are formed in the support portion, and the plurality of recesses respectively correspond in position to the plurality of openings. An antenna element is provided.

[0011] Further, the present invention provides, as a sixth antenna element, a fourth antenna element, wherein the upper conductor, the at least one lower conductor, the at least one leg portion, and the at least one feeding portion do not overlap with each other in a plan view. An antenna element is provided. <�

[0012] Further, the present invention provides, as a seventh antenna element, a sixth antenna element, wherein the support portion has at least a central support portion that supports the central portion, an annular support portion that supports the annular portion, and a plurality of connection support portions that respectively support the plurality of connection portions, the central support portion and the annular support portion are spaced apart from each other and are connected by the connection support portion. An antenna element is provided.

[0013] Further, the present invention provides, as an eighth antenna element, a seventh antenna element, wherein the annular support portion has an additional recess recessed downward in the vertical direction, and the annular portion extends along the upper surface of the annular support portion including the additional recess. An antenna element is provided.

[0014] Further, the present invention provides, as a first antenna device, any one of the antenna elements from the first to the eighth, a ground conductor, and a dielectric interposed between the antenna element and the ground conductor. To provide an antenna device comprising the same.

Advantages of the Invention

[0015] In the antenna element according to the present invention, the lower conductor forms a capacitor with the upper conductor. Thereby, miniaturization of the antenna element can be achieved. Further, a plurality of openings are formed in the upper conductor, thereby realizing weight reduction of the antenna element. An antenna device including such an antenna element can also be miniaturized and lightened.

Brief Description of the Drawings

[0016] [Figure 1] It is a perspective view showing an antenna device according to an embodiment of the present invention. [Figure 2] It is a top view showing the antenna device of FIG. 1. [Figure 3] It is a side view showing the antenna device of FIG. 1. [Figure 4] It is a schematic diagram showing a first modification of the antenna device according to the present invention. [Figure 5] It is a top view showing a second modification of the antenna device according to the present invention. Only the plate-like portion is shown for the support portion. [Figure 6] It is a top view showing a third modification of the antenna device according to the present invention. Only the plate-like portion is shown for the support portion. [Figure 7] It is a top view showing a fourth modification of the antenna device according to the present invention. Only the plate-like portion is shown for the support portion. [Figure 8] It is a schematic diagram showing a fifth modification of the antenna device according to the present invention. [Figure 9] It is a schematic diagram showing a sixth modification of the antenna device according to the present invention. [Figure 10] It is a schematic diagram showing a seventh modification of the antenna device according to the present invention. [Figure 11] It is a perspective view showing a patch antenna disclosed in Patent Document 1.

Modes for Carrying Out the Invention

[0017] Referring to Figures 1 and 2, an antenna device 10 according to one embodiment of the present invention comprises an antenna element 20, a support portion (dielectric) 30, and a ground conductor 40. In other words, the antenna device 10 is constituted by the antenna element 20 being provided on the ground conductor 40 via the support portion (dielectric) 30.

[0018] As shown in Figures 1 and 2, the antenna element 20 comprises an upper conductor 201, at least one lower conductor 203, at least one leg portion 205, and at least one feed portion 207.

[0019] As can be seen from Figures 1 and 2, in this embodiment, the antenna element 20 is mounted on the support portion 30. That is, the upper conductor 201, at least one lower conductor 203, at least one leg portion 205, and at least one feed portion 207 are mounted on the support portion 30. In this embodiment, the vertical direction is the Z direction. The +Z direction is upward, and the -Z direction is downward.

[0020] The antenna element 20 shown in Figures 1 and 2 can be formed, for example, using the laser direct structuring (LDS) method. Specifically, a support portion 30 is fabricated using a resin material in which a metal complex is dispersed. Laser light is irradiated onto a predetermined area on the surface of the support portion 30 to reduce the metal complex. Selective plating is performed on a predetermined area on the surface of the support portion 30 using the reduced metal as a catalytic nucleus. The resulting plated film becomes the antenna element 20. In this method, since the laser light is irradiated from above the support portion 30, the entire formed plated film can be viewed from above. Therefore, in this embodiment, the upper conductor 201, at least one lower conductor 203, at least one leg portion 205, and at least one feed portion 207 do not overlap with each other in a plan view. However, the present invention is not limited thereto. The antenna element 20 may be formed using one or more metal plates. In that case, if the antenna element 20 has a self-supporting structure, a flat dielectric plate can be used instead of the support portion 30. In this case, the antenna element 20 is mounted on a dielectric plate.

[0021] As shown in Figure 3, the ground conductor 40 is positioned directly below the support portion 30. In other words, the antenna device 10 is mounted on the ground conductor 40. As the ground conductor 40, a circuit board can be used in which conductor layers are formed on the entire upper and lower surfaces of an insulating substrate. In this case, it is preferable that the conductor layer on the upper surface and the conductor layer on the lower surface are connected to each other using vias or the like.

[0022] As shown in Figure 3, in this embodiment, a ground layer 31 is formed on the lower surface of the support portion 30, covering almost its entire surface. The ground conductor 40, positioned below the support portion 30, is electrically connected to the ground layer 31 formed on the lower surface of the support portion 30. However, the present invention is not limited to this. The ground layer 31 does not necessarily have to be formed on the lower surface of the support portion 30.

[0023] As shown in Figure 2, in this embodiment, the outer shape of the upper conductor 201 is approximately square in plan view. However, the present invention is not limited to this. The outer shape of the upper conductor 201 does not have to be approximately square in plan view. However, in order to enable communication by circular polarization in the antenna device 10, it is preferable that the outer shape of the upper conductor 201 is approximately n times symmetric in plan view. Here, n is a multiple of 4 (the same applies hereafter).

[0024] As shown in Figure 2, the upper conductor 201 has a central portion 211, an annular portion 213, and a plurality of connecting portions 215. The central portion 211 is the part that includes the center of the upper conductor 201 in a plan view. The annular portion 213 is the part along the outer edge of the upper conductor 201. The connecting portions 215 are the parts that connect the central portion 211 and the annular portion 213. The connecting portions 215 have an end region 217 which is a relatively wide area connected to the annular portion 213. However, the boundary between the central portion 211 and the connecting portions 215, and the boundary between the annular portion 213 and the connecting portions 215 are not clearly defined.

[0025] As can be seen from Figures 1 and 2, the central portion 211, the annular portion 213, and the connecting portion 215 define a plurality of openings 22. In other words, the upper conductor 201 has a plurality of openings 22. Each of the openings 22 is located between the central portion 211 and the annular portion 213 in a plan view. In this embodiment, there are four connecting portions 215 and four openings 22. By forming the openings 22, the amount of metal material can be reduced, resulting in a lighter weight.

[0026] As shown in Figure 2, in this embodiment, the number of lower conductors 203 and the number of legs 205 are each four. Also, in this embodiment, the number of power supply units 207 is two. In other words, in this embodiment, at least one lower conductor 203 comprises four lower conductors 203. Also, at least one leg 205 comprises four legs 205. Furthermore, at least one power supply unit 207 comprises two power supply units 207. However, the present invention is not limited thereto. The number of lower conductors 203, legs 205 and power supply units 207 can each be arbitrarily set. In this embodiment, the number of lower conductors 203 and the number of legs 205 are equal, but they do not necessarily have to be equal.

[0027] As shown in Figure 2, in this embodiment, the lower conductors 203 are arranged at the corners of the support portion 30. In this embodiment, the shape of the lower conductors 203 is L-shaped in plan view. However, the present invention is not limited thereto. The shape of each of the lower conductors 203 can be arbitrarily set. However, it is preferable that the lower conductors 203 are formed with approximately n rotational symmetry with respect to the center of the support portion 30 in plan view.

[0028] As can be seen from Figures 1 and 2, each of the lower conductors 203 is connected to the corresponding leg 205. In other words, at least one lower conductor 203 and at least one leg 205 are connected one-to-one.

[0029] As shown in Figure 1, the support portion 30 includes a central support portion 301, an annular support portion 303, at least one connecting support portion 305, at least one power supply support portion 307, and a plate-shaped portion 309. In this embodiment, there are four connecting support portions 305. Also in this embodiment, there are two power supply support portions 307.

[0030] As can be seen from Figures 1 and 3, the central support portion 301, the annular support portion 303, the connecting support portion 305, and the power supply support portion 307 protrude upward from the upper surface of the plate-shaped portion 309. The central support portion 301, the annular support portion 303, and the connecting support portion 305 define a plurality of recesses 32. In other words, the support portion 30 has a plurality of recesses 32 that are recessed downward in the vertical direction. The recesses 32 correspond in position to the openings 22 of the upper conductor 201, respectively. The formation of the recesses 32 reduces the loss of the antenna device 10 due to the resin. On the other hand, the annular support portion 303 has an additional recess 33 that is recessed downward in the vertical direction.

[0031] As can be seen from Figures 1 and 2, the central support 301 corresponds to the central part 211 and supports the central part 211. The annular support 303 corresponds to the annular part 213 and supports the annular part 213. The central support 301 and the annular support 303 are located apart from each other and are connected by connecting support 305. Each connecting support 305 corresponds to each connecting part 215. Each connecting support 305 supports the corresponding connecting part 215. The power supply support 307 corresponds to each power supply part 207. Each power supply support 307 supports the corresponding power supply part 207.

[0032] As shown in Figures 1 and 2, in this embodiment, the central portion 211 is provided on the upper surface of the central support portion 301. The outer shape of the central portion 211 is approximately octagonal in plan view.

[0033] As shown in Figures 1 and 2, in this embodiment, the annular portion 213 extends along the upper surface of the annular support portion 303, including the additional recess 33. In plan view, the annular portion 213 has a substantially square frame shape that follows the outer shape of the upper conductor 201. In plan view, the annular portion 213 is located outward from the central portion 211 and surrounds the central portion 211 without any breaks. The additional recess 33 is located at the longitudinal center of each side of the annular portion 213.

[0034] As shown in Figures 1 and 2, in this embodiment, there are four connecting portions 215. Each connecting portion 215 is provided on the upper surface of the corresponding connecting support portion 305. Each connecting portion 215 corresponds to one of the eight corners of the central portion 211, and also to one of the four corners of the annular portion 213. Each connecting portion 215 connects the corresponding corner of the central portion 211 to the corresponding corner of the annular portion 213.

[0035] As can be seen from Figures 1 and 3, in this embodiment, the central portion 211 and the connecting portion 215 are located on a specific plane perpendicular to the vertical direction. The annular portion 213 is partially located on the specific plane. The annular portion 213 has a portion located below the specific plane in the vertical direction, i.e., a portion corresponding to the additional recess 33.

[0036] As shown in Figures 1 and 2, the lower conductor 203 is provided on the upper surface of the plate-like portion 309 and is separated from the upper conductor 201 in the vertical direction. More specifically, the lower conductor 203 is located below the upper conductor 201 in the vertical direction.

[0037] As shown in Figures 1 and 2, the legs 205 extend from the annular portion 213. In this embodiment, the legs 205 extend outward from the outer edge of the annular portion 213 in a plan view. More specifically, each of the legs 205 extends diagonally downward from one of the four corners of the annular portion 213.

[0038] As shown in Figures 1 and 2, the power supply section 207 extends from the upper conductor 201. In this embodiment, the power supply section 207 extends from the central section 211 toward one of the corners of the annular section 213, and then extends toward the central section of the recess 32. However, the present invention is not limited thereto. The power supply section 207 may also extend from the connecting section 215.

[0039] As can be seen from Figure 2, the two virtual lines connecting the center of the central section 211 and the two feed points 207 form a 90-degree angle in plan view. More specifically, if we define the connection points between each of the feed points 207 and the central section 211 as feed points 209, then the two virtual lines connecting the center of the central section 211 and the two feed points 209 form a 90-degree angle in plan view. This makes it possible to realize circular polarization communication using a two-point feeding method with the antenna device 10.

[0040] In the antenna device 10 shown in Figures 1 to 3, each of the lower conductors 203 forms a capacitor with the upper conductor 201 or the connecting portion 215. That is, the presence of the lower conductors 203 affects the resonant frequency of the antenna device 10. More specifically, the presence of the lower conductors 203 lowers the resonant frequency compared to when they are absent. In other words, the presence of the lower conductors 203 makes it possible to miniaturize the antenna element 20 having a predetermined resonant frequency, and thereby makes it possible to miniaturize the antenna device 10.

[0041] In the antenna device 10 shown in Figures 1 to 3, the shape and size of the lower conductor 203 affect the setting of the resonant frequency. In addition, the shape and size of the annular portion 213 also affect the resonant frequency. By positioning the annular portion 213 partially below a specific plane in the vertical direction, the resonant frequency can be lowered compared to when the entire annular portion 213 is positioned on the specific plane. This enables miniaturization of the antenna element 20 and thus miniaturization of the antenna device 10.

[0042] The antenna device 10 shown in Figures 1 to 3 employs a two-point feeding system. Specifically, by inputting a first input signal to one of the feeding sections 207 and a second input signal with a phase difference of 90 degrees from the first input signal to the other feeding section 207, the antenna element 20 can be made to communicate using highly circularly polarized waves. In order to achieve highly circularly polarized communication, it is preferable that the outer shape of the upper conductor 201 and the arrangement of the lower conductor 203 be approximately n rotationally symmetrical.

[0043] Although the present invention has been described above with reference to embodiments, the present invention is not limited to the embodiments described above, and various modifications and changes are possible without departing from the spirit of the present invention.

[0044] (First variation) Referring to Figure 4, the antenna element 20A comprises an upper conductor 201A, at least one lower conductor 203A, at least one leg portion 205A, and at least one feed portion 207A. The antenna element 20A does not have a support portion 30 (see Figures 1-3).

[0045] As shown in Figure 4, the antenna element 20A is positioned above the ground conductor 40A, away from the ground conductor 40A, and constitutes the antenna device 10A. The antenna element 20A and the ground conductor 40A are fixed to each other by a support member (not shown). Air exists as a dielectric between the antenna element 20A and the ground conductor 40A. Thus, in the antenna device of the present invention, the dielectric may be air. In this modified example, the annular portion 213A may also have a portion located below a specific plane in the vertical direction, similar to the annular portion 213 shown in Figures 1 to 3.

[0046] (Second variation) Referring to Figure 5, in the antenna element 20B, the shape of the central portion 211B of the upper conductor 201 is approximately square in plan view. Thus, the shape of the central portion 211B of the upper conductor 201 can be set arbitrarily. However, in order to realize communication using circular polarization, it is preferable that the shape of the central portion 211B be n times symmetric.

[0047] In the antenna element 20B, each of the feed points 207B is connected to one of the four corners of the central section 211B. In this modified example as well, the two virtual lines connecting the center of the central section 211B to the two feed points 207B form a 90-degree angle in plan view. More specifically, if the connection point between each of the feed points 207B and the central section 211B is called the feed point 209, then the two virtual lines connecting the center of the central section 211B to the two feed points 209 form a 90-degree angle in plan view.

[0048] (Third variation) Referring to Figure 6, in the antenna element 20C, each of the connecting portions 215C corresponds to one of the eight sides of the central portion 211C. Each of the connecting portions 215C connects the corresponding side of the central portion 211C to the corresponding corner of the annular portion 213C. The feed portion 207C is located in a slot 219 formed in the connecting portion 215C in a plan view. In a plan view, the feed portion 207C extends from one of the sides of the central portion 211C toward the corner of the annular portion 213C.

[0049] (Fourth variation) Referring to Figure 7, the antenna element 20D differs from the antenna element 20C of the third modification in that it has a dummy slot 219D. Compared to the antenna element 20C of the third modification, the antenna element 20D can use less metal material, thus making the antenna element 20D lighter.

[0050] (Fifth variation) Referring to Figure 8, the antenna element 20E differs from the first modified antenna element 20A in that the central portion 211E of the upper conductor 201E is located below the end region 217E of the connecting portion 215E in the vertical direction. Thus, in the antenna element of the present invention, the central portion of the upper conductor and the connecting portion do not have to be located on the same plane in part. The antenna element 20E may have the shape shown in Figure 5, Figure 6, or Figure 7 in a plan view. Furthermore, the annular portion 213A of the upper conductor 201E may have a portion located below a specific plane in the vertical direction.

[0051] (Sixth variation) Referring to Figure 9, antenna device 10F differs from antenna device 10A in Figure 4 in that dielectric material 34 is filled between the antenna element 20A and the ground conductor 40A. Also, referring to Figure 10, antenna device 10G differs from antenna device 10E in Figure 8 in that dielectric material 34 is filled between the antenna element 20E and the ground conductor 40A, and in the space above the central portion 211E. In either case, various resins such as epoxy resin and Teflon (registered trademark) can be used as the dielectric material 34. Thus, various materials can be used as the dielectric material in the antenna device of the present invention. [Explanation of Symbols]

[0052] 10, 10A, 10B, 10C, 10D, 10E, 10F, 10G Antenna Equipment 20, 20A, 20B, 20C, 20D, 20E Antenna Elements 201, 201A, 201E Upper conductor 203, 203A Lower conductor 205,205A Legs 207, 207A, 207B, 207C Power supply section 209 Power supply point 211,211A,211B,211C,211E Central part 213,213A Ring section 215,215A,215C,215E Connection part 217,217A,217E End area 219 slots 219D Dummy Slot 22 Opening 30 Support part (dielectric) 301 Central support part 303 Annular support section 305 Connection support part 307 Power supply support section 309 Plate-like part 32 recesses 33 Additional recess 34 Dielectrics 40,40A Ground conductor

Claims

1. An antenna element that constitutes an antenna device by being placed on a ground conductor via a dielectric, The antenna element comprises an upper conductor, at least one lower conductor, at least one leg, and at least one feed point. The upper conductor has a plurality of openings formed therein. The upper conductor has a central portion, an annular portion, and a plurality of connecting portions. The annular portion is located away from the central portion and surrounds the central portion without any breaks. The aforementioned opening is located between the central portion and the annular portion in a plan view. Each of the aforementioned connecting parts connects the central part and the annular part. The at least one leg extends from the annular portion, The at least one lower conductor is separated from the upper conductor in the vertical direction and is connected to the at least one leg portion. The at least one power supply unit extends from the upper conductor, The outer shape of the upper conductor is fourfold symmetrical in a plan view. The aforementioned at least one lower conductor comprises four lower conductors, The aforementioned at least one leg comprises four legs, The at least one lower conductor and the at least one leg are connected in a one-to-one relationship. Antenna element.

2. The antenna element according to claim 1, The aforementioned at least one power supply unit comprises two power supply units, The two imaginary lines connecting the center of the central section and the two power supply sections form a 90-degree angle in a plan view. Antenna element.

3. The antenna element according to claim 1, The upper conductor, the at least one lower conductor, the at least one leg, and the at least one power supply unit are mounted on a support made of resin. Antenna element.

4. The antenna element according to claim 3, The support portion has a plurality of recesses that are recessed downward in the vertical direction. The plurality of recesses correspond in position to the plurality of openings. Antenna element.

5. The antenna element according to claim 3, The upper conductor, the at least one lower conductor, the at least one leg, and the at least one power supply portion do not overlap with each other in a plan view. Antenna element.

6. The antenna element according to claim 5, The support portion comprises at least a central support portion that supports the central portion, an annular support portion that supports the annular portion, and a plurality of connecting support portions that each support the plurality of connecting portions. The central support portion and the annular support portion are located apart from each other and are connected by the connecting support portion. Antenna element.

7. The antenna element according to claim 6, The annular support portion has an additional recess that is recessed downward in the vertical direction, The annular portion extends along the upper surface of the annular support portion, including the additional recess. Antenna element.

8. An antenna element according to any one of claims 1 to 7, Ground conductor and, A dielectric interposed between the antenna element and the ground conductor An antenna device equipped with the following features.

Images