antenna

Abstract

To provide a more inexpensive, compact antenna.SOLUTION: Provided is an antenna for transmitting and receiving a wireless signal conforming to a prescribed communication standard that comprises: a metal plate arranged on a circuit board; a first supporting part that connects the metal plate and a feeding point formed on the circuit board to each other, and supports the metal plate; at least one second supporting part that connects the metal plate and a ground formed on the circuit board to each other, and supports the metal plate; and a plurality of extended parts extended from an outer edge of the metal plate toward the circuit board, and formed so as not to be in contact with the circuit board. The plurality of extended parts act as a perturbation element that forms two spatially intersecting exciting modes.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an antenna. [Background technology]

[0002] In recent years, a system has been developed that estimates the arrival angle of a signal based on the Phase Difference of Arrival (PDoA). In order to realize the above-mentioned arrival angle estimation, for example, a circularly polarized patch antenna as disclosed in Patent Document 1 is used. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-120069 A Summary of the Invention [Problem to be solved by the invention]

[0004] In order to ensure desired antenna characteristics, circularly polarized patch antennas are often disposed on expensive high-frequency substrates having a certain thickness or greater, resulting in high manufacturing costs.

[0005] Furthermore, when an array configuration is used for estimating the angle of arrival, the antenna must be made smaller.

[0006] Therefore, the present invention has been made in consideration of the above problems, and an object of the present invention is to realize a cheaper and smaller antenna. [Means for solving the problem]

[0007] In order to solve the above problem, according to one aspect of the present invention, there is provided an antenna for transmitting and receiving wireless signals compliant with a prescribed communication standard, comprising: a metal plate arranged on a circuit board; a first support portion connecting a power feed point formed on the circuit board to the metal plate and supporting the metal plate; at least one second support portion connecting a ground formed on the circuit board to the metal plate and supporting the metal plate; and a plurality of extension portions extending from an outer edge of the metal plate toward the circuit board but formed so as not to contact the circuit board, wherein the plurality of extension portions operate as perturbation elements that form two spatially intersecting excitation modes. Effect of the Invention

[0008] As described above, according to the present invention, it is possible to realize a cheaper and smaller antenna. [Brief description of the drawings]

[0009] [Figure 1] 1 is a top view of an antenna 10 according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a side view of the antenna 10 according to the embodiment. [Diagram 3] FIG. 2 is a perspective view of an antenna 10 according to the embodiment. [Figure 4] FIG. 11 is a top view of an antenna 20 according to a second embodiment of the present invention. [Diagram 5] FIG. 2 is a side view of the antenna 20 according to the embodiment. [Figure 6] FIG. 2 is a perspective view of an antenna 20 according to the embodiment. [Figure 7] FIG. 11 is a diagram for explaining an array antenna configuration including a plurality of antennas 20 according to a second embodiment of the present invention. [Figure 8] 4 is a graph showing the relationship between the strength of mutual coupling between antennas 10 according to the first embodiment of the present invention and the spacing between the antennas 10. [Figure 9]10 is a graph showing the relationship between the strength of mutual coupling between antennas 20 according to the second embodiment of the present invention and the spacing between the antennas 20. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functional configurations are designated by the same reference numerals, and duplicated explanations will be omitted.

[0011] <1. Overview> As described above, typical circularly polarized antennas tend to have high manufacturing costs because they use expensive high-frequency substrates.

[0012] On the other hand, when a patch antenna is constructed using only a metal plate without using a high-frequency substrate, there is a concern that the antenna may become large in size.

[0013] This is because in a configuration using a high-frequency substrate, the wavelength is shortened according to the dielectric constant, making it possible to miniaturize the antenna, whereas in a configuration not using a high-frequency substrate, the same effect cannot be obtained.

[0014] For this reason, when attempting to configure a patch antenna without using a high frequency substrate, particularly when attempting to configure an array antenna, it is necessary to introduce some means for miniaturizing the antenna.

[0015] For example, in an array antenna for realizing arrival angle estimation, the arrangement interval between each antenna is required to be equal to or less than half the wavelength λ of the signal.

[0016] For this reason, if the dimensions of a single antenna exceed 1 / 2λ, it becomes extremely difficult to construct an array antenna.

[0017] The technical idea according to one embodiment of the present invention has been conceived in consideration of the above points, and aims to realize a cheaper and smaller antenna.

[0018] The antenna configurations according to the two embodiments will now be described in detail.

[0019] 2. First embodiment First, a first embodiment of the present invention will be described.

[0020] An antenna 10 according to a first embodiment of the present invention is a circularly polarized antenna that transmits and receives radio signals that comply with a prescribed communication standard.

[0021] The above-mentioned prescribed communication standard includes, for example, ultra wide band (UWB) wireless communication.

[0022] Hereinafter, a configuration example of the antenna 10 according to the present embodiment will be described with reference to FIGS.

[0023] Fig. 1 is a top view of an antenna 10 according to a first embodiment of the present invention, Fig. 2 is a side view of the antenna 10 according to the same embodiment, and Fig. 3 is a perspective view of the antenna 10 according to the same embodiment.

[0024] As shown in FIGS. 1 to 3, the antenna 10 according to this embodiment includes a metal plate 110, a first support portion 121, a second support portion 122, and four extension portions 131 to .

[0025] The metal plate 110, the first support portion 121, the second support portion 122, and the four extension portions 131 to 134 according to this embodiment may be integrally formed using a metal material.

[0026] In FIG. 1, first support portion 121, second support portion 122, and four extension portions 131 to 134 are emphasized by a dot pattern in order to clarify the boundaries between the respective portions.

[0027] (Metal plate 110) The metal plate 110 according to this embodiment is disposed on the circuit board 30, as shown in FIG.

[0028] Moreover, the metal plate 110 according to this embodiment may be formed asymmetrically in a shape similar to the letter H, as exemplified in Figures 1 and 3. This is to realize the generation of circularly polarized waves by perturbation excitation, as will be described later.

[0029] (First support portion 121) The first support portion 121 according to this embodiment connects the power supply point 40 formed on the circuit board 30 to the metal plate 110, and supports the metal plate 110, as shown in FIGS.

[0030] Furthermore, the first support portion 121 according to this embodiment may be formed so as to extend from the outer edge of the metal plate 110 toward the circuit board 30, as shown in FIGS.

[0031] (Second support portion 122) The second support portion 122 according to this embodiment connects a ground (not shown) formed on the circuit board 30 to the metal plate 110, and supports the metal plate 110.

[0032] Furthermore, the second support portion 122 according to this embodiment may be formed so as to extend from the outer edge of the metal plate 110 toward the circuit board 30, as shown in FIGS.

[0033] The first support portion 121 and the second support portion 122 enable the antenna 10 to stand independently on the circuit board 30 .

[0034] (Extension part 131~Extension part 134) The extensions 131 to 134 according to this embodiment extend from the outer edge of the metal plate 110 toward the circuit board 30, as shown in FIGS. 1 to 3, and are formed so as not to come into contact with the circuit board 30. As shown in FIG.

[0035] Further, one of the features of the extensions 131 to 134 according to this embodiment is that they operate as perturbation elements that form two excitation modes that are spatially approximately orthogonal to each other.

[0036] Here, we will explain the outline of perturbation excitation. When two spatially orthogonal excitation modes are designed to have slightly different resonant frequencies, a phase difference of 90° can be given between the two resonant frequencies.

[0037] In other words, perturbation excitation is a method for generating circularly polarized waves by using the above-mentioned 90° phase difference.

[0038] To realize perturbation excitation, as described above, it is necessary to design two spatially orthogonal excitation modes so that their resonant frequencies are slightly different from each other.

[0039] For this reason, the metal plate 110 and the extensions 131 to 134 according to this embodiment are formed so that the lengths of the current paths in the two excitation modes that are spatially approximately orthogonal to each other are different from each other.

[0040] For example, in the example shown in FIGS. 1 to 3, the length L1 of the extensions 131 and 134 and the length L2 of the extensions 132 and 133 are the same.

[0041] On the other hand, in metal plate 110, the length from the portion connected to extension 131 to the portion connected to extension 134 and the length from the portion connected to extension 132 to the portion connected to extension 133 are different from each other.

[0042] Due to the shape of metal plate 110 as described above, in antenna 10 illustrated in Figures 1 to 3, current paths of different lengths are formed in the excitation mode by extensions 131 and 134 and the excitation mode by extensions 132 and 133, thereby realizing perturbation excitation.

[0043] Although Figures 1 to 3 show an example in which the length L1 of extensions 131 and 134 and the length L2 of extensions 132 and 133 are the same, if lengths L1 and L2 are different, it is also possible for metal plate 110 to have a shape that is close to symmetrical.

[0044] Furthermore, if the polarized waves to be generated are not limited to circularly polarized waves, the antenna 10 does not necessarily have to include four extensions.

[0045] For example, it is possible to operate three extensions as perturbation elements to form two spatially intersecting excitation modes, thereby generating an elliptically polarized wave.

[0046] In this case, the metal plate 110 may be formed in an asymmetrical shape similar to the letter T or L.

[0047] 3. Second embodiment Next, a second embodiment of the present invention will be described.

[0048] The antenna 20 according to the second embodiment of the present invention is a circularly polarized antenna that transmits and receives radio signals that comply with a prescribed communication standard, similar to the antenna 10 according to the first embodiment.

[0049] Hereinafter, a configuration example of the antenna 20 according to the present embodiment will be described with reference to FIGS.

[0050] In the following, the description will be given mainly focusing on the differences from the antenna 10 according to the first embodiment, and detailed description of the configuration common to the antenna 10 according to the first embodiment will be omitted.

[0051] Fig. 4 is a top view of an antenna 20 according to a second embodiment of the present invention, Fig. 5 is a side view of the antenna 20 according to the same embodiment, and Fig. 6 is a perspective view of the antenna 20 according to the same embodiment.

[0052] As shown in FIGS. 4 to 6, the antenna 20 according to this embodiment includes a metal plate 210, a first support portion 221, two second support portions 222a and 222b, four extension portions 231 to 234, and an opening portion 240.

[0053] The metal plate 210, the first support portion 221, the two second support portions 222a and 222b, and the four extension portions 231 to 234 according to this embodiment may be integrally formed using a metal material.

[0054] In FIG. 4, in order to clarify the boundaries between the various parts, the first support part 221, the two second support parts 222a and 222b, and the four extension parts 231 to 234 are highlighted with a dot pattern.

[0055] In addition, in FIG. 5, the extensions 232 and 234 are omitted in order to prioritize visibility.

[0056] (Metal plate 210) The metal plate 210 according to this embodiment is disposed on the circuit board 30, as shown in FIG.

[0057] Moreover, the metal plate 210 according to this embodiment may be formed into a symmetrical octagon, as exemplified in FIG. 4 and FIG.

[0058] (First support portion 221) The first support portion 221 according to this embodiment connects the power supply point 40 formed on the circuit board 30 to the metal plate 210, and supports the metal plate 210, as shown in FIGS.

[0059] Furthermore, the first support portion 221 according to this embodiment may be formed so as to extend from the outer edge of the metal plate 210 toward the circuit board 30, as shown in FIGS.

[0060] (Second support portion 222a and second support portion 222b) The second support portion 222a and the second support portion 222b according to this embodiment connect a ground (not shown) formed on the circuit board 30 to the metal plate 210, and support the metal plate 210.

[0061] In addition, the second support portion 222a and the second support portion 222b according to this embodiment may be formed to extend from the edge of the opening 240 formed in the metal plate 210 toward the circuit board 30, as shown in FIGS. 4 and 6.

[0062] The antenna 20 can stand independently on the circuit board 30 by the first support portion 221, the second support portion 222a, and the second support portion 222b.

[0063] (Extension part 231~Extension part 234) The extensions 231 to 234 according to this embodiment extend from the outer edge of the metal plate 210 toward the circuit board 30, as shown in FIGS. 4 to 6, and are formed so as not to come into contact with the circuit board 30. As shown in FIG.

[0064] Further, one of the features of the extensions 231 to 234 according to this embodiment is that they operate as perturbation elements that form two excitation modes that are spatially approximately orthogonal to each other.

[0065] As described above, the metal plate 210 according to this embodiment has a symmetrical shape. Therefore, in order to realize perturbation excitation, the extensions 231 to 234 according to this embodiment are formed so that the lengths of the current paths in the two excitation modes that are spatially approximately orthogonal to each other are different from each other.

[0066] More specifically, in this embodiment, the lengths of the two extensions 231 and 234 that form one of the two excitation modes that are approximately orthogonal in space are formed to be different from the lengths of the two extensions 231 and 234 that form the other.

[0067] 5, the length L1 of the extension 231 and the length L2 of the extension 233 may be designed to be different from each other. Similarly, the length L2 of the extension 232 and the length L1 of the extension 234 may be designed to be different from each other.

[0068] According to the above design, current paths of different lengths are formed in the excitation mode by extensions 231 and 234 having length L1 and in the excitation mode by extensions 232 and 233 having length L2, thereby realizing perturbation excitation.

[0069] Furthermore, the second support portion 222a and the second support portion 222b according to this embodiment may operate as a perturbation element that forms one of two excitation modes that are spatially approximately orthogonal to each other.

[0070] When second support portion 222a and second support portion 222b are operated as perturbation elements, there is no need to increase the difference between length L1 and length L2 described above, and it is possible to avoid the extension portion becoming long enough to come into contact with circuit board 30.

[0071] (Opening 240) As shown in Figures 4 and 6, the opening 240 in this embodiment is formed in the metal plate 210 between two extension portions 231 and 234 that form one of two excitation modes that are spatially approximately orthogonal to each other, and between two extension portions 232 and 233 that form the other.

[0072] According to the opening 240 of this embodiment, the current path between the tip of the extension portion 231 and the tip of the extension portion 234, and the current path between the tip of the extension portion 232 and the tip of the extension portion 233 can be extended, thereby making it possible to make the antenna 20 smaller.

[0073] <4. Array antenna configuration> Next, an array antenna configuration including a plurality of antennas 10 according to the first embodiment or antennas 20 according to the second embodiment of the present invention will be described.

[0074] FIG. 7 is a diagram for explaining an array antenna configuration including a plurality of antennas 20 according to the second embodiment of the present invention.

[0075] As shown in FIG. 7, in the array antenna configuration, a plurality of antennas 20 may be arranged so that the intervals form an equilateral triangle.

[0076] In the example shown in FIG. 7, the reference for the arrangement interval is the center of metal plate 210 (the center of opening 240), but the reference may be any point on antenna 20 or may be feed point 40.

[0077] Although not shown, in an array antenna configuration, the multiple antennas 10 may also be arranged so that the intervals form an equilateral triangle.

[0078] Here, the length of the gap between the antennas 20 is ΔL (ΔL=Dλ).

[0079] In this case, the shorter ΔL is, the more compact the array antenna can be. However, if ΔL is too short, there is a possibility that the desired antenna performance cannot be obtained.

[0080] For this reason, antenna 10 and antenna 20 may be arranged so that the distance between them and other antennas of the same configuration is less than or equal to half the wavelength of a wireless signal conforming to a prescribed communication standard and greater than or equal to a prescribed length D0λ determined by an index.

[0081] An example of the index is the strength of mutual coupling between antennas.

[0082] FIG. 8 is a graph showing the relationship between the strength of mutual coupling between the antennas 10 and the spacing between the antennas 10 according to the first embodiment of the present invention.

[0083] FIG. 9 is a graph showing the relationship between the strength of mutual coupling between the antennas 20 and the spacing between the antennas 20 according to the second embodiment of the present invention.

[0084] As shown in FIGS. 8 and 9, the strength of mutual coupling between the antennas tends to decrease as the spacing between the antennas decreases.

[0085] It is also known that if the strength of mutual coupling between antennas is too weak, it becomes difficult to obtain desired antenna performance.

[0086] For this reason, the arrangement interval of the antennas 10 or 20 may be designed to be equal to or greater than a prescribed length D0λ at ​​which the mutual coupling between the antennas has a prescribed strength or greater.

[0087] The prescribed length D0λ may be determined in consideration of the desired antenna performance, the measurement results of mutual coupling, and the like.

[0088] The index for determining the prescribed length D0λ is not limited to the strength of mutual coupling between the antennas, but may be any index that can be used to determine antenna performance.

[0089] <5. Supplementary Information> Although the preferred embodiment of the present invention has been described in detail above with reference to the accompanying drawings, the present invention is not limited to such an example. It is clear that a person having ordinary knowledge in the technical field to which the present invention pertains can conceive of various modified or altered examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present invention. [Explanation of symbols]

[0090] 10, 20: antenna, 110, 210: metal plate, 121, 221: first support, 122, 222a, 222b: second support, 131 to 134, 231 to 234: extension, 240: opening, 30: circuit board, 40: power supply point

Claims

1. An antenna for transmitting and receiving wireless signals that comply with a prescribed communication standard, A metal plate disposed on the circuit board; a first support portion that connects a power supply point formed on the circuit board and the metal plate and supports the metal plate; at least one second support portion that connects a ground formed on the circuit board to the metal plate and supports the metal plate; A plurality of extensions extending from an outer edge of the metal plate toward the circuit board and formed so as not to contact the circuit board; Equipped with The plurality of extensions act as perturbation elements that form two spatially intersecting excitation modes. antenna.

2. the metal plate and the plurality of extensions are formed such that lengths of current paths in the two spatially intersecting excitation modes are different from each other; 2. The antenna of claim 1.

3. The four extensions act as perturbation elements that form two excitation modes that are substantially orthogonal in space; Equipped with An antenna as claimed in any one of claims 1 or 2.

4. The lengths of the two extension parts forming one of the two excitation modes that are approximately orthogonal in space and the lengths of the two extension parts forming the other of the two excitation modes are formed to be different from each other.

4. The antenna of claim 3.

5. an opening formed in the metal plate between two of the extensions forming one of the two excitation modes substantially perpendicular to each other in space and between two of the extensions forming the other of the two excitation modes; Further comprising:

5. The antenna of claim 4.

6. the two second support portions connecting an edge of the opening portion to a ground and acting as perturbation elements forming one of the two excitation modes that are substantially orthogonal in space; Equipped with 6. The antenna of claim 5.

7. The antenna is arranged so that the distance between the antenna and other antennas of the same configuration is equal to or less than half the wavelength of a radio signal conforming to a prescribed communication standard and equal to or greater than a prescribed length. An antenna according to any one of claims 1 to 6.

8. The prescribed communication standard includes ultra-wideband wireless communication, An antenna according to any one of claims 1 to 7.

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