Antenna equipment

Abstract

This antenna device comprises a flat plate-shaped first element and a second element having a plate-shaped portion provided in parallel to the first element. The plate-shaped portion comprises three or more power-feeding path sections extending radially from a power-feeding section of a center portion, and three or more antenna sections that are extended from end sections of the three or more power-feeding path sections and are connected to a grounding section of the first element.

Description

Technical Field

[0001] This disclosure relates to an antenna device.

Background Art

[0002] In sensor terminals constituting a wireless sensor network, primary batteries such as button cells, solar cells, thermoelectric conversion elements, etc. are generally used as power sources. However, primary batteries require battery replacement, and solar cells and thermoelectric conversion elements have problems of high material costs. Such problems related to power sources are barriers to the spread of wireless sensor networks.

[0003] In a sensor system using RFID (radio frequency identifier) as a communication unit, since it cannot spontaneously transmit communication radio waves, it has low power consumption and can utilize energy harvesting as a power source. RF energy harvesting uses wireless power for part or all of the power source. This enables the realization of wireless and battery-free sensor terminals.

[0004] The wireless power distributed in the environment varies greatly depending on the distance from the transmitter, reflection, interference, etc., which is a problem when applying wireless power to a sensor terminal. Therefore, it is required to realize highly efficient sensor driving by RF energy harvesting through a power management configuration.

[0005] One method of wireless power transmission is distributed power supply. In this technology, a plurality of antennas are arranged on the ceiling and the phases of each antenna are controlled to reduce the exposure level to humans and supply high power pinpointedly. To realize this technology, it is necessary to efficiently transmit power from the power transmitter, and thus it is necessary to design a small and highly efficient antenna.

[0006] For example, Patent Document 1 discloses a circularly polarized antenna having an inverted F antenna provided on one side of two orthogonal sides of a rectangular ground conductor plate, a dipole antenna provided on the other side, and an EM feeding section positioned opposite each of the open ends of both antennas. In this technology, the circularly polarized antenna is made smaller and more efficient by providing single-point feeding by the EM feeding section to the inverted F antenna (λ / 4 type) and dipole antenna (λ / 2 type) which are orthogonally arranged on a sheet metal. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2018-170561 [Overview of the project] [Problems that the invention aims to solve]

[0008] Incidentally, the performance requirements for antennas used in wireless power transmission include being small enough to be placed in multiple locations on the ceiling, being highly efficient to improve power efficiency, having circular polarization directivity because the orientation of the receiving antennas is random, and having an antenna pattern suitable for distributed power supply.

[0009] Furthermore, generally speaking, the radiation pattern of an antenna suitable for distributed power transmission has a secant-square characteristic, where the radio waves radiated in the linear direction are small, and the radio waves radiated at both ends are large. The secant-square characteristic is the same as the cosecant-square beam in radar and base station antennas, as it only differs in how θ is chosen. Conical beams are considered effective in reproducing this secant-square characteristic.

[0010] However, conventional circularly polarized antennas often exhibit elliptical polarization, resulting in a bias in the direction of radio wave emission. Furthermore, their large size presents a problem when used as antennas for distributed power supply.

[0011] The purpose of this disclosure is to provide an antenna device that can be miniaturized while having wide directivity. [Means for solving the problem]

[0012] The antenna device related to this disclosure is A flat plate-shaped first element, A second element having a plate-like portion provided parallel to the first element, Equipped with, The plate-like portion is Three or more power supply paths radiate outwards from the central power supply section, Three or more antenna sections extending from the ends of the three or more power supply path sections and connected to the ground section of the first element, It is equipped with. [Effects of the Invention]

[0013] According to this disclosure, it is possible to achieve wide directivity while miniaturizing the device. [Brief explanation of the drawing]

[0014] [Figure 1] This figure shows an antenna device according to an embodiment of the present disclosure. [Figure 2] This is a diagram showing the first element. [Figure 3] This figure shows the return loss characteristics of the antenna device according to this embodiment. [Figure 4] This figure shows the linear polarization pattern of the antenna device according to this embodiment. [Figure 5] This figure shows the axial ratio characteristics of the antenna device according to this embodiment. [Figure 6] This figure shows the directional characteristics of the antenna device according to this embodiment. [Figure 7] This figure shows an antenna device with the first element grounded to concrete. [Figure 8] This figure shows the return loss characteristics of the antenna device shown in Figure 7. [Figure 9]It is a diagram showing the axial ratio characteristics of the antenna device shown in FIG. 7. [Figure 10] It is a diagram showing the directivity characteristics of the antenna device shown in FIG. 7. [Figure 11] It is a diagram showing an antenna device in which the first element is grounded to a metal foil. [Figure 12] It is a diagram showing the return loss characteristics of the antenna device shown in FIG. 11. [Figure 13] It is a diagram showing the axial ratio characteristics of the antenna device shown in FIG. 11. [Figure 14] It is a diagram showing the directivity characteristics of the antenna device shown in FIG. 11. [Figure 15] It is a diagram showing an example in which the second element of the antenna device is a substrate. [Figure 16] It is a diagram showing the plate-like portion of the antenna device shown in FIG. 15. [Figure 17] It is a diagram showing the connection portion of the antenna device shown in FIG. 15. [Figure 18] It is a diagram showing the first element of the antenna device shown in FIG. 15. [Figure 19] It is a diagram showing the return loss characteristics shown in FIG. 15. [Figure 20] It is a diagram showing the axial ratio characteristics of the antenna device shown in FIG. 15. [Figure 21] It is a diagram showing the directivity characteristics of the antenna device shown in FIG. 15.

Mode for Carrying Out the Invention

[0015] (Embodiment) Hereinafter, embodiments of the present disclosure will be described in detail based on the drawings. FIG. 1 is a diagram showing an antenna device 100 according to an embodiment of the present disclosure. In the embodiment, a rectangular coordinate system (X, Y, Z) is used for the description. The same rectangular coordinate system (X, Y, Z) is also shown in the drawings described later.

[0016] For example, the antenna device 100 is installed on the XY plane (horizontal plane) with mutually orthogonal X and Y axes. That is, the X and Y directions are parallel to the horizontal direction, and the Z direction is perpendicular to the horizontal direction.

[0017] As shown in Figure 1, the antenna device 100 is, for example, a power transmission antenna used in a wireless power transmission system, and radiates a circularly polarized conical beam. The antenna device 100 comprises a first element 110 and a second element 120.

[0018] As shown in Figure 2, the first element 110 is a flat conductive plate configured in a circular shape, and is the part that is attached to the installation location of the antenna device 100. A coaxial cable connector for supplying power is connected to the center P of the first element 110, and it is possible to send current to the power supply section 121A of the second element 120, which will be described later.

[0019] The first element 110 is provided with grounding points 111 connected to ground. The grounding points 111 are connection points with the second element 120, and four of them are provided at positions corresponding to the outer edge of the first element 110. Note that each grounding point 111 may be connected on the first element 110.

[0020] The four grounding points 111 are arranged such that the distance between any two adjacent grounding points 111 is equal. For example, in this embodiment, the distance between two adjacent grounding points 111 is such that the angle formed by the line connecting each grounding point 111 to the center P of the first element 110 is the same angle (90 degrees in this embodiment). Note that the range of the same angle includes not only perfectly identical angles but also a very small range of angles (for example, 1 or 2 degrees).

[0021] Furthermore, the first element 110 has a first element side antenna section 112. There are a total of four first element side antenna sections 112, corresponding to each of the four grounding sections 111, and each has a first section 112A and a second section 112B. Since each first element side antenna section 112 has the same shape, only one first element side antenna section 112 will be described below, and the descriptions of the other first element side antenna sections 112 will be omitted.

[0022] The first part 112A extends from a position corresponding to the grounding portion 111 along the outer edge of the first element 110, for example in a counterclockwise direction in Figure 2. The first part 112A extends to a position corresponding to the front side of the grounding portion 111 adjacent to the grounding portion 111 in a counterclockwise direction from the base end position.

[0023] The second part 112B extends linearly from the end of the first part 112A opposite to the grounding portion 111 at its base position toward the center of the first element 110. The second part 112B extends to a position corresponding to the front side of the center of the first element 110.

[0024] Furthermore, the length of the first element side antenna section 112 is one-quarter of the wavelength of the radio waves radiated by the antenna device 100. The length of the first element side antenna section 112 may be set appropriately according to the wavelength radiated by the antenna device 100.

[0025] The first element side antenna portion 112 is formed by forming a notch 113 in the first element 110. In other words, the notch 113 is the portion of the first element 110 that has been cut out so that the first element side antenna portion 112 has a first end corresponding to the ground portion 111 and a second end that is a free end.

[0026] The notch 113 is formed along the first element side antenna portion 112 such that there is a substantially constant distance between the first element side antenna portion 112 and the first elements 110 other than the first element side antenna portion 112. A notch 113 is provided for each first element side antenna portion 112, and their shapes are all the same.

[0027] In this way, by forming a first element-side antenna portion 112 having a certain length from the portion corresponding to the grounding portion 111 using the notch portion 113, a part of the first element 110 can be made to function as an antenna.

[0028] Furthermore, the width of the notch 113 is appropriately set to a length that does not affect the impedance in the antenna device 100 (for example, 2 mm if the width of the first element side antenna portion 112 is 4 mm).

[0029] As shown in Figure 1, the second element 120 is provided on the positive side in the Z direction of the first element 110 and has the function of supplying power to the antenna device 100 and also functions as an antenna. The second element 120 has a plate-shaped portion 121 and a connecting portion 122.

[0030] The plate-like portion 121 is arranged parallel to the first element 110 and is spaced apart from the first element 110. Therefore, an air layer is provided between the first element 110 and the second element 120. The range of parallelism includes not only perfectly parallel surfaces but also those with a slight incline (for example, around 1 or 2 degrees).

[0031] The plate-shaped portion 121 has a circular contour and the same outer diameter as the circular shape of the first element 110. In other words, the plate-shaped portion 121 has the same contour shape as the first element 110. The plate-shaped portion 121 includes a power supply portion 121A, a power supply path portion 121B, and an antenna portion 121C.

[0032] The power supply section 121A is the central part of the plate-shaped section 121 and is the part that supplies power to the antenna device 100. The power supply section 121A is located at the same position as the center P of the first element 110 in the X and Y directions and supplies the current sent via the coaxial cable connected to the first element 110 to the antenna section 121C.

[0033] The power supply path section 121B is a portion that extends radially from the power supply section 121A and constitutes a path for supplying power to the antenna section 121C. A total of four power supply path sections 121B are provided, each having the same shape. The four power supply path sections 121B are arranged such that the angle between two adjacent power supply path sections 121B is the same angle (90 degrees in this embodiment). Note that the range of the same angle includes not only perfectly identical angles but also a very small range of angles (for example, 1 or 2 degrees).

[0034] The antenna section 121C functions as part of the antenna on the second element 120 side, powered by the feed section 121A. The antenna section 121C is provided in each of the four feed path sections 121B, and each has the same shape. The antenna section 121C has a straight section C1 and an arc section C2.

[0035] The straight section C1 extends from the end of the power supply path section 121B in a direction perpendicular to that of the power supply path section 121B. Furthermore, each straight section C1 extends toward the side of the power supply path section 121B that is located downstream in a counterclockwise direction from the power supply path section 121B corresponding to the base end, so as not to interfere with each other.

[0036] The arc-shaped section C2 is connected to the end of the straight section C1 opposite to the power supply path section 121B and is configured in an arc shape.

[0037] The arc of the arc portion C2 is configured to be approximately the same as the arc of the first element 110. The arc portion C2 is positioned so that, for example, when viewed from the Z direction, it overlaps with the outer edge of the first element 110. The arc portion C2 extends counterclockwise (counterclockwise direction in the XY plane in Figure 1) from the end of the straight portion C1 to a position corresponding to the ground portion 111 of the first element 110. Note that the arc portion C2 may be positioned offset from the outer edge of the first element 110.

[0038] The connection portion 122 is the part that connects the antenna portion 121C to the ground portion 111 of the first element 110, and functions as part of the antenna on the second element 120 side. The connection portion 122 is provided perpendicular to the antenna portion 121C. The connection portion 122 extends from the end of the arc portion C2 of the antenna portion 121C opposite to the end on the straight portion C1 side (feed path portion 121B side), toward the negative Z direction, and connects to the ground portion 111. Note that the range of perpendicularity includes not only perfectly perpendicular (90 degrees) but also those that are slightly off from 90 degrees (for example, about 1 or 2 degrees).

[0039] In the second element 120 configured in this way, the antenna section 121C and the connection section 122 are supplied with power via the power supply section 121A and the power supply path section 121B, so that the antenna section 121C and the connection section 122 function as the antenna on the second element side (hereinafter referred to as the second element side antenna section).

[0040] Furthermore, the length of the second element side antenna section (the sum of the lengths of the antenna section 121C and the connection section 122) is one-quarter of the wavelength of the radio waves radiated by the antenna device 100. For example, if the resonant frequency of the antenna device 100 is 920 MHz and the diameter of the first element 110 is set to 70 mm, the connection section 122 can be set to approximately 25 mm. As long as the length of the second element side antenna section is one-quarter of the wavelength of the radio waves, the length of the connection section 122 and the length of the antenna section 121C can be adjusted as appropriate.

[0041] Radio waves are emitted from the second element antenna section, which is powered. Specifically, current flows through the antenna section 121C in a direction parallel to the X and Y directions (horizontal direction), and Φ waves parallel to the horizontal direction are emitted. In addition, current flows through the connection section 122 in the Z direction (vertical direction), which is perpendicular to the horizontal direction, and θ waves parallel to the vertical direction are emitted.

[0042] Furthermore, the current flowing through the second element antenna section is sent to the first element antenna section 112, which is connected to the ground section 111, and radio waves are also radiated from the first element antenna section 112. In other words, when current flows horizontally through the first element antenna section 112, Φ waves parallel to the horizontal direction are radiated.

[0043] In this way, the antenna device 100 can produce circularly polarized waves that are close to a perfect circle by radiating Φ waves and θ waves to roughly the same extent.

[0044] Furthermore, since the four second-element antenna sections and the four first-element antenna sections 112 are configured with the same shape and are arranged at equal intervals, the phase difference of each radio wave is isolated by 90 degrees. As a result, radiation in the forward direction (Z direction) is canceled out, and a conical beam circular polarization antenna that radiates significantly to the periphery (X and Y directions) can be constructed.

[0045] Next, the simulation results of the antenna characteristics of the antenna device 100 according to this embodiment will be described. Figure 3 is a diagram showing the return loss characteristics of the antenna device 100 according to this embodiment. In Figure 3, the horizontal axis represents frequency (GHz) and the vertical axis represents the return loss characteristics (dB).

[0046] As shown in Figure 3, the resonant frequency of the antenna device 100 is polarized to 920 MHz, which is the peak of the even mode, and 1.2 GHz, which is the peak of the odd mode.

[0047] For example, in the configuration described in Patent Document 1, the resonant frequency of the inverted-F antenna is 2.310 GHz, and the resonant frequency of the dipole antenna is 2.55 GHz, so the resonant frequency of the circularly polarized antenna is 2.44 GHz.

[0048] In contrast, in this embodiment, for example, by extracting the 920MHz (even mode) on the low-frequency side, the resonant frequency can be significantly reduced compared to the conventional configuration. This characteristic contributes to miniaturization of the antenna device 100.

[0049] Furthermore, the relative bandwidth of the antenna device 100 is 5.4%. Since the relative bandwidth of a typical patch antenna is 3-4%, it can be confirmed that the relative bandwidth of the antenna device 100 according to this embodiment is a good value compared to a typical patch antenna.

[0050] Figure 4 shows the linear polarization pattern of the antenna device 100 according to this embodiment. In Figure 4, the solid line shows the theta wave radiation pattern, and the dashed line shows the Φ wave radiation pattern.

[0051] As shown in Figure 4, the difference between theta waves and Φ waves is within 2 dB, confirming that theta waves and Φ waves are radiated to roughly the same extent. This radiation pattern of theta waves and Φ waves can be adjusted by changing the lengths of the antenna sections on the first element and the second element.

[0052] Figure 5 shows the axial ratio characteristics of the antenna device 100 according to this embodiment. In Figure 5, the horizontal axis represents angle (deg) and the vertical axis represents axial ratio (dB).

[0053] For example, in the configuration described in Patent Document 1, the axial ratio characteristics of 3 dB or less are 136.9 degrees to 205.6 degrees and 333.7 degrees to 43.3 degrees.

[0054] In contrast, as shown in Figure 5, the axial ratio characteristics of the antenna device 100 according to this embodiment are within 2 dB or less over a wide angular range, so it can be confirmed that circularly polarized waves close to a perfect circle are being radiated. From this, it can be confirmed that the antenna device 100 according to this embodiment provides better axial ratio characteristics compared to the conventional configuration.

[0055] Figure 6 shows the directional characteristics of the antenna device 100 according to this embodiment. In Figure 6, L1 represents left-hand circular polarization and L2 represents right-hand circular polarization.

[0056] As shown in Figure 6, it can be confirmed that the antenna device 100 mainly radiates left-hand circular polarization and does not radiate right-hand circular polarization. More specifically, the arc portion C2 of the antenna portion 121C extends counterclockwise from the end of the straight portion C1, and the first portion 112A extends counterclockwise from the ground portion 111. Therefore, the antenna device 100 in this embodiment is designed to radiate left-hand circular polarization. As a result, it can be confirmed from the results shown in Figure 6 that right-hand circular polarization is not radiated, and the radiation efficiency of the antenna device 100 is good without the left-hand circular polarization being canceled out.

[0057] Next, the disturbance resistance of the antenna device 100 will be described. Figure 7 shows the antenna device 100 with the first element 110 grounded to concrete C.

[0058] The antenna device 100 is used, for example, by grounding the first element 110 to concrete C, as shown in Figure 7. In this case, as shown in Figure 8, the return loss characteristics can be seen to be slightly shifted to the lower frequency side for both even and odd modes, compared to the return loss characteristics of the configuration not grounded to concrete C shown in Figure 1 (see Figure 3).

[0059] Since this is only a minor difference from the configuration shown in Figure 1, it is possible to adjust the target resonant frequency (e.g., 920 MHz) by, for example, fine-tuning the length of the connection and antenna section in the second element antenna. Alternatively, the length of the first element antenna can also be fine-tuned.

[0060] Furthermore, as shown in Figure 9, the axial ratio characteristics are above 2 dB around 130 to 180 degrees, but remain below 3 dB, confirming that this falls within the range of good circular polarization over a wide area.

[0061] Furthermore, as shown in Figure 10, the directional characteristics (L3 in Figure 10) are almost identical to those of the configuration not grounded to concrete C shown in Figure 1 (see Figure 4). In Figure 10, L4 indicates the area with the strongest radio wave radiation, while L5 and L6 indicate areas where the radio wave radiation intensity is 3 dB lower than L4.

[0062] Furthermore, the antenna device 100 is used by grounding the first element 110 to the metal foil M, for example, as shown in Figure 11. In this case, the return loss characteristics are as shown in Figure 12, and it can be confirmed that the resonant frequencies are shifted to the higher frequency side for even modes and to the lower frequency side for odd modes, unlike the return loss characteristics of the configuration grounded to the concrete C shown in Figure 7 (see Figure 8).

[0063] This also involves only minor differences from the configuration shown in Figure 1. Therefore, it is possible to adjust the target resonant frequency (e.g., 920 MHz) by, for example, fine-tuning the length of the connection and antenna sections in the second element antenna section. Alternatively, the length of the first element antenna section may also be fine-tuned.

[0064] Furthermore, as shown in Figure 13, the axial ratio characteristics are above 2 dB in the range of 0 to 60 degrees, but remain below 3 dB, confirming that this falls within the range of good circular polarization over a wide area.

[0065] Furthermore, as shown in Figure 14, the directional characteristics (L7 in Figure 14) are almost identical to those of the configuration not grounded to the metal foil M shown in Figure 1. In Figure 14, L8 indicates the region with the strongest radio wave radiation, while L9 and L10 indicate regions where the radio wave radiation intensity is 3 dB lower than L8.

[0066] From these observations, it can be seen that in the configurations shown in Figures 7 and 11, no significant change in characteristics is observed even when the first element 110 is grounded to another object. As a result, it can be confirmed that the antenna device 100 according to this embodiment is resistant to disturbances.

[0067] Next, an example of an application of the antenna device 100 according to this embodiment will be described. Figure 15 shows an example in which the second element 120 of the antenna device 100 is mounted on a substrate.

[0068] As shown in Figure 15, the plate-shaped portion 121 and the connecting portion 122 of the second element 120 can be made into a substrate. For example, as shown in Figure 16, the plate-shaped portion 121 can be configured as a circular substrate 122D similar to that of the first element 110.

[0069] Furthermore, as shown in Figure 17, the connecting portion 122 can be a rectangular substrate 122A that includes, for example, a connecting portion 122 located on the opposite side of the center of the plate-shaped portion 121. In this case, an engagement groove 122B is formed in the center of the substrate, which allows two substrates to be engaged. By engaging the engagement groove 122B of another substrate 122A with this engagement groove 122B, it becomes possible to provide four connecting portions 122 arranged at equal intervals (90-degree intervals).

[0070] Furthermore, as shown in Figure 18, a connector 110A for the coaxial cable is provided in the center of the first element 110. Current is sent to the plate-shaped part 121 via this connector 110A. Alternatively, the metal parts of each component may be shaped by attaching copper foil to the top and bottom of the substrate and using vias to ensure conductivity between the top and bottom. In addition, the tip of the first element side antenna part 112 may be bent from the configuration shown in Figure 2.

[0071] Furthermore, the simulation results of the return loss characteristics for the configuration shown in Figure 15, as shown in Figure 19, show that the peak of the odd-mode resonance around 1.2 GHz becomes gradual, and only the even-mode resonance around 920 MHz appears as a peak.

[0072] In other words, even with the configuration shown in Figure 15, it is possible to extract only the frequency around 920 MHz, so the same characteristics as the configuration shown in Figure 1 can be obtained.

[0073] Furthermore, regarding the axial ratio characteristics, as shown in Figure 20, although there is a range where it is slightly above 2 dB, it remains below 3 dB over a wide area, confirming that circularly polarized waves close to a perfect circle are being emitted.

[0074] Furthermore, as shown in Figure 21, it can be confirmed that the directivity characteristics (L11 shown in Figure 21) are comparable to those of the configuration shown in Figure 1. In Figure 21, L12 indicates the area where radio wave radiation is strongest, while L13 and L14 indicate areas where the radio wave radiation intensity is 3 dB lower than L12. Also, due to a slight difference in radio wave radiation intensity between the left and right sides, L12, L13, and L14 are in the opposite direction to the results in Figures 10 and 14.

[0075] From the above, it can be confirmed that the desired characteristics can be obtained even if the second element 120 of the antenna device 100 is mounted on a substrate.

[0076] As described above, this embodiment is configured such that the antenna portion 121C and the connection portion 122 of the second element 120 constitute the second element side antenna portion, thus enabling the antenna device 100 to radiate Φ waves and θ waves.

[0077] Specifically, the connection part 122 allows for securing the antenna length in the height direction (Z direction), which reduces the area in which the antenna device 100 is placed, and consequently allows for miniaturization of the antenna device 100 as a whole.

[0078] Furthermore, since each of the multiple power supply path sections 121B and the multiple antenna sections 121C has the same shape, power can be supplied evenly to each second element side antenna section. As a result, good characteristics can be obtained over a wide area.

[0079] In other words, this embodiment allows for miniaturization while maintaining wide directivity. As a result, it can contribute to the practical application of distributed wireless power supply systems.

[0080] Furthermore, since the first element 110 is provided with the first element side antenna section 112, the radiation of Φ waves can be reinforced.

[0081] Furthermore, by providing a notch 113 in the first element 110, the first element side antenna section 112 can be formed, eliminating the need to provide a separate antenna section and resulting in a simpler configuration.

[0082] In the above embodiment, an air layer was provided between the first element 110 and the second element 120, but the disclosure is not limited thereto, and for example, a dielectric layer may be provided.

[0083] Furthermore, in the above embodiment, the first element 110 and the second element 120 were provided with a gap between them, but the disclosure is not limited thereto, and the second element may be provided so as to overlap the first element. In this case, a connecting portion does not need to be provided.

[0084] Furthermore, in the above embodiment, the antenna portion 121C was composed of a straight portion C1 and an arc portion C2, but the present disclosure is not limited thereto, and for example, it may be composed of only an arc portion.

[0085] Furthermore, although the above embodiment had a configuration with two elements (first element 110 and second element 120), the disclosure is not limited thereto, and for example, a configuration with three or more elements is also possible. In this case, elements other than the first and second elements can have the same shape as the second element.

[0086] Furthermore, although the above embodiment had four antenna sections, this disclosure is not limited to this, and the number of antenna sections can be any number as long as there are three or more. Also, the angle between two adjacent power supply path sections is appropriately changed according to the number of antenna sections. For example, if there are three antenna sections, the angle is 120 degrees, and if there are five antenna sections, the angle is 72 degrees.

[0087] Furthermore, although the first element side antenna section 112 in the above embodiment was composed of a first part and a second part, this disclosure is not limited thereto, and for example, it may be composed of only the first part.

[0088] Furthermore, although the above embodiment included a first element-side antenna section 112, this disclosure is not limited thereto, and the first element-side antenna section may not be provided.

[0089] Furthermore, in the above embodiment, the length of the second element side antenna section (the sum of the lengths of the antenna section 121C and the connection section 122) was one-quarter of the wavelength of the radio waves radiated by the antenna device 100, but this disclosure is not limited thereto. For example, the length of the second element side antenna section may be n times (n is 1 or more) one-quarter of the wavelength of the radio waves radiated by the antenna device 100.

[0090] Furthermore, in the above embodiment, the length of the first element side antenna portion was one-quarter of the wavelength of the radio waves radiated by the antenna device 100, but this disclosure is not limited thereto. For example, the length of the first element side antenna portion may be m times (where m is 1 or more) one-quarter of the wavelength of the radio waves radiated by the antenna device 100.

[0091] Furthermore, the embodiments described above are merely examples of how this disclosure may be implemented, and the technical scope of this disclosure should not be limited by them. In other words, this disclosure can be implemented in various ways without departing from its essence or its main features.

[0092] All disclosures in the specification, drawings, and abstract contained in the Japanese application 2022-090204, filed on June 2, 2022, are incorporated herein by reference. [Industrial applicability]

[0093] The antenna device of this disclosure is useful as an antenna device that can be miniaturized while having wide directivity. [Explanation of Symbols]

[0094] 100 Antenna equipment 110 First Rules 111 Grounding part 112 First element side antenna section 112A Part 1 112B Part 2 113 Notch 120 Second Element 121 Plate-like part 121A Power supply section 121B Power supply path section 121C Antenna Section 122 Connection part C1 Straight section C2 Arc section

Claims

1. A flat first element, A second element having a plate-like portion provided parallel to the first element, Equipped with, The plate-like portion is Three or more power supply paths radiate outwards from the central power supply section, Three or more antenna sections extending from the ends of the three or more power supply path sections and connected to the ground section of the first element, Equipped with, Antenna device.

2. The plate-like portion is provided at a distance from the first element, The second element has a connecting portion that connects the end of the antenna portion opposite to the end on the power supply path side to the ground portion of the first element. The antenna device according to claim 1.

3. The aforementioned connection portion is provided perpendicular to the antenna portion. The sum of the lengths of the antenna section and the connection section is n times one-quarter of the wavelength of the radio waves radiated by the antenna device (where n is 1 or greater). The antenna device according to claim 2.

4. The first element has a first element side antenna portion formed by forming a notch, The first element side antenna portion has a first end corresponding to the ground portion of the first element and a second end which is a free end. The antenna device according to claim 1.

5. The first element side antenna portion has a first portion including the outer edge of the first element, and a second portion including the free end and extending from the end of the first portion toward the center of the first element. The antenna device according to claim 4.

6. The length of the first element side antenna portion is one-quarter of the wavelength of the radio waves radiated by the antenna device. The antenna device according to claim 4.

7. An air layer or a dielectric layer is provided between the first element and the plate-like portion. The antenna device according to claim 1.

8. The three or more power supply paths are arranged such that the angle between two adjacent power supply paths is the same. The antenna device according to claim 1.

9. The plate-like portion has the same contour shape as the first element. The antenna device according to claim 1.

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