Antenna device and wireless communication device

Abstract

An antenna device and a wireless communication device that are small in size and capable of transmitting and receiving a vertically polarized wave without requiring an additional noise countermeasure are provided. An antenna device (100) includes a feed antenna element (101) having an element portion (101A) parallel to a ground surface, one end of the antenna device (100) being electrically connected to a supply source (203) that supplies a wireless communication signal; and a parasitic antenna element (102) having a vertical element portion arranged perpendicular to the ground surface and arranged near the other end of the feed antenna element (101). Further, a wireless communication device (200) includes a substrate (201) on which a ground layer (202) having a reference potential and the supply source (203) that supplies the wireless communication signal are formed; and the antenna device (100).

Description

Technical Field

[0001] The present invention relates to an antenna device and a wireless communication device. Background Art

[0002] When radio waves are sent and received between wireless communication devices, the polarization waves of the antennas need to be matched to each other. When the opposing wireless communication device only sends and receives vertically polarized waves, the wireless communication device itself also needs to be able to send and receive vertically polarized waves. For example, when communicating with an access point having a dipole antenna arranged perpendicular to the ground, the antenna of the slave unit also needs to be able to send and receive vertically polarized waves. In order to send and receive vertically polarized waves, it is necessary to install an antenna element having a portion perpendicular to the ground. In addition, as the frequency of the radio waves to be sent and received becomes lower (the wavelength of the radio waves becomes longer), it is necessary to increase the length of the portion of the antenna element perpendicular to the ground. In other words, it is necessary to increase the height of the wireless communication device. However, when the height of the wireless communication device increases, the installation location of the wireless communication device is limited. In addition, when the portion of the antenna element perpendicular to the ground is shortened in order to reduce the height of the wireless communication device, the communicable distance is shortened.

[0003] Patent document 1 describes an antenna device comprising: a plate-shaped floor providing a ground potential; an inverted L-shaped feed element connected to the floor via a feed unit; and a linear parasitic element arranged at predetermined intervals relative to the floor in a manner that capacitively couples to the floor. In Patent document 1, the linear parasitic element (which has a length less than half the wavelength of the radio wave to be transmitted and received) is connected to an inductor (which provides a predetermined inductance). In Patent document 1, the inductance provided by the inductor is set to a value that resonates in series with the capacitance (formed between the floor and the feed element). As a result, a current that is phase-shifted by 90 degrees from the current flowing through the feed element is excited in the parasitic element. Therefore, the length of the parasitic element, which serves as a reflective element, can be shortened to less than half the wavelength of the radio wave to be transmitted and received.

[0004] Patent Document 2 describes a radio device comprising: a first antenna connected to a conductor plate serving as a ground conductor via a feed unit; and a second antenna connected to the conductor plate via a connection unit and a terminal and comprising an element arranged parallel to the first antenna. Furthermore, Patent Document 2 improves the radio device's high-frequency characteristics by adjusting the spacing between the element of the second antenna and the first antenna. Patent Document 2 describes miniaturizing the second antenna by bending the portion of the element extending away from the radio device.

[0005] Citation List

[0006] Patent Literature

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-170590

[0008] [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-028392 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] However, Patent Document 1 uses a current flowing through the floor, and the feed element and parasitic element are arranged at separate locations. This requires a design to suppress noise around the antenna, such as from the feed element and parasitic element. Therefore, placing the feed element and parasitic element at separate locations requires additional noise countermeasures.

[0011] Furthermore, Patent Document 2 does not mention a technique for matching polarized waves of antennas between wireless communication devices.

[0012] An object of the present invention is to provide an antenna device and a wireless communication device that are small in size and capable of transmitting and receiving vertically polarized waves without requiring additional noise countermeasures.

[0013] Solutions for solving problems

[0014] An antenna device according to a first aspect of the present invention includes: a feed antenna element having one end electrically connected to a supply source for supplying a wireless communication signal and provided with an element portion parallel to the ground; and a parasitic antenna element having a vertical element portion arranged perpendicular to the ground and arranged near the other end of the feed antenna element.

[0015] A wireless communication device according to a second aspect of the present invention includes: a substrate on which a ground layer having a reference potential and a supply source for supplying a wireless communication signal are formed; and the above-mentioned antenna device.

[0016] Effects of the Invention

[0017] An antenna device and a wireless communication device that are small in size and capable of transmitting and receiving vertically polarized waves without requiring additional noise countermeasures can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a front view showing an example of the antenna device according to the first exemplary embodiment of the present invention;

[0019] Figure 2 is a perspective view showing an example of the antenna device according to the first exemplary embodiment of the present invention;

[0020] Figure 3 is a block diagram showing an example of a configuration of a wireless communication apparatus according to a first exemplary embodiment of the present invention;

[0021] Figure 4 is a diagram showing an example of measurement results of radiation characteristics of the antenna device without a parasitic antenna element according to the first exemplary embodiment of the present invention;

[0022] Figure 5 is a diagram showing an example of measurement results of radiation characteristics of the antenna device according to the first exemplary embodiment of the present invention;

[0023] Figure 6 is a front view showing an example of an antenna device according to a second exemplary embodiment of the present invention;

[0024] Figure 7 is a perspective view showing an example of an antenna device according to a second exemplary embodiment of the present invention;

[0025] Figure 8 is a diagram showing an example of measurement results of radiation characteristics of the antenna device according to the second exemplary embodiment of the present invention;

[0026] Figure 9 is a front view showing an example of an antenna device according to a third exemplary embodiment of the present invention;

[0027] Figure 10 is a perspective view showing an example of an antenna device according to a third exemplary embodiment of the present invention; and

[0028] Figure 11 is a diagram showing an example of measurement results of radiation characteristics of the antenna device according to the third exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0029] Exemplary embodiments of the present invention will be described below with reference to the accompanying drawings.

[0030] First exemplary embodiment

[0031] First, refer to Figures 1 to 5 A first exemplary embodiment of the present invention is described. Figure 1 and Figure 2 are diagrams each showing an example of the antenna device 100 according to the first exemplary embodiment of the present invention. Figure 3 is a block diagram illustrating an example of the configuration of a wireless communication device 200 including the antenna device 100. In this specification, an axis perpendicular to the ground is defined as the Z axis, an axis perpendicular to the Z axis and parallel to the substrate 201 (described later) is defined as the X axis, and an axis perpendicular to the Z axis and perpendicular to the substrate 201 is defined as the Y axis. That is, the X axis and the Y axis are axes parallel to the ground.

[0032] like Figure 1 and Figure 2As shown, antenna device 100 includes a feed antenna element 101 and a parasitic antenna element 102. Antenna device 100 transmits and receives target radio waves. Examples of target radio waves for antenna device 100 include microwaves (SHF: Super High Frequency) and ultra-high frequency waves (UHF: Ultra High Frequency). The wavelength of microwaves is approximately 10 mm to 100 mm, and the wavelength of ultra-high frequency waves is approximately 100 mm to 1000 mm.

[0033] The feeding antenna element 101 is provided on a substrate 201 on which a ground layer 202 having a reference potential and a supply source 203 (reference potential) for supplying a radio communication signal are formed. Figure 3 ). The feed antenna element 101 includes an element portion 101A parallel to the ground. That is, the element portion 101A is arranged parallel to the X-axis. The feed antenna element 101 is provided on the edge side of the substrate 201 in such a manner that the element portion 101A extends along the edge on the side opposite to the ground side. One end of the feed antenna element 101 is electrically connected to the supply source 203. Hereinafter, the end of the feed antenna element 101 connected to the supply source 203 will be referred to as the feed end. The feed antenna element 101 is formed of a straight or elongated plate-shaped electrical conductor such as copper, brass, or aluminum. The feed antenna element 101 can be formed as a conductor pattern of the substrate 201.

[0034] Specifically, if Figure 1 and Figure 2 As shown, feed antenna element 101 is, for example, an inverted L-shaped element, with element portion 101A and element portion 101B connected perpendicularly. One element portion 101A, which forms the L-shape, is arranged parallel to the ground. In other words, element portion 101A is arranged parallel to the X-axis. The other element portion 101B, which forms the L-shape, is arranged perpendicular to the ground; in other words, element portion 101B is arranged parallel to the Z-axis. The other end (feeding end) of element portion 101B, which is not connected to element portion 101A, is connected to supply source 203.

[0035] The parasitic antenna element 102 includes a vertical element portion arranged perpendicular to the ground. Figure 1 and Figure 2As shown, parasitic antenna element 102 according to the first exemplary embodiment includes only a vertical element portion. In other words, parasitic antenna element 102 is arranged parallel to the Z-axis. Furthermore, parasitic antenna element 102 is arranged near the other end (the end on the side opposite to the feeding end) of feeding antenna element 101. More specifically, the end of parasitic antenna element 102 on the feeding antenna element 101 side is arranged a predetermined distance away from the edge of substrate 201. The end of parasitic antenna element 102 is arranged near the end of feeding antenna element 101, which is on the side opposite to the end of element portion 101A connected to element portion 101B. Note that the distance between the end of parasitic antenna element 102 and the other end (the end on the side opposite to the feeding end) of feeding antenna element 101 is a distance that allows high-frequency current to be excited in parasitic antenna element 102 by feeding feeding antenna element 101.

[0036] The parasitic antenna element 102 is formed of a linear or elongated plate-shaped conductor such as copper, brass, or aluminum. The parasitic antenna element 102 can be formed as a conductor pattern of a printed wiring board. Note that the resonant frequency of the parasitic antenna element 102 matches the resonant frequency of the feed antenna element 101.

[0037] The length of parasitic antenna element 102 (the length of the vertical element portion) is less than half the wavelength of the radio waves to be transmitted and received. In the first exemplary embodiment, for example, when the frequency of the radio waves to be transmitted and received is 815 MHz, the length of parasitic antenna element 102 (the vertical element portion) is half the wavelength of the radio waves or slightly shorter, for example, 135 mm. Note that the length (height) of parasitic antenna element 102 is not limited to the above length because it depends on the wavelength of the target radio waves.

[0038] like Figure 3 As shown, the wireless communication device 200 includes a substrate 201 on which a ground layer 202 and a supply source 203 are formed, and Figure 1 and Figure 2 The antenna device 100 is shown.

[0039] The substrate 201 is a member on a flat plate made of an electrically insulating material such as resin, etc. Examples of the resin include glass cloth material, epoxy resin, and the like.

[0040] Ground layer 202 is a plate-shaped conductor member made of a conductor such as copper. Specifically, ground layer 202 is a ground conductor for a mounting unit for a circuit such as a transmission / reception circuit or a signal processing circuit. Ground layer 202 is electrically connected to feed antenna element 101 via supply source 203 and provides a reference potential (ground potential) to feed antenna element 101.

[0041] The supply source 203 serves as an input terminal for a high-frequency signal (as a wireless communication signal) to the feeding antenna element 101 and an output terminal for a high-frequency signal from the feeding antenna element 101. The supply source 203 includes, for example, two terminals, one of which is connected to the feeding antenna element 101 and the other of which is connected to the ground layer 202.

[0042] Next, we will refer to Figure 2 The operation of the antenna device 100 according to the first exemplary embodiment will be described. Figure 2 In FIG, the current flowing through the ground layer 202 is indicated by a solid arrow, the current flowing through the feed antenna element 101 is indicated by a dashed arrow, and the current induced in the parasitic antenna element 102 is indicated by a dashed arrow. Figure 2 In the illustrated example, to reduce the height of antenna device 100, the first side of ground layer 202, perpendicular to the ground, is shorter than the second side of ground layer 202, parallel to the ground. Furthermore, current tends to flow in a portion with a length commensurate with the resonant frequency. Therefore, ideally, the total length of the first side of ground layer 202 and feed antenna element 101 is approximately half the wavelength of the radio waves to be transmitted and received. However, at a resonant frequency of approximately 815 MHz, the total length of the first side of ground layer 202 and feed antenna element 101 is less than the length commensurate with the resonant frequency. Therefore, a greater amount of current flows in the second side, which is longer than the first side. As a result, when parasitic antenna element 102 is not used, the intensity of horizontally polarized waves increases, while the intensity of vertically polarized waves decreases. However, in antenna device 100 according to the first exemplary embodiment, the intensity of vertically polarized waves can be increased by using parasitic antenna element 102.

[0043] First, a high-frequency current flows from ground layer 202 to feed antenna element 101, and the high-frequency current is supplied to feed antenna element 101 via supply source 203. Next, as the high-frequency current flows through feed antenna element 101, it excites a high-frequency current in parasitic antenna element 102 through electromagnetic coupling. At this point, parasitic antenna element 102 resonates at a frequency approximately half the wavelength of the radio waves to be transmitted and received. As a result, parasitic antenna element 102 can increase the intensity of vertically polarized waves in antenna device 100. Note that the intensity of the high-frequency current excited by parasitic antenna element 102 depends on the intensity of the high-frequency current flowing through feed antenna element 101. Therefore, the resonant frequency of parasitic antenna element 102 needs to match the resonant frequency of feed antenna element 101.

[0044] Next, refer to Figure 4 and Figure 5 , the radiation characteristics of the vertically polarized wave of the antenna device 100 according to the first exemplary embodiment will be described. Figure 4and Figure 5 Shown are measurement results of radiation characteristics when the frequency of radio waves to be transmitted and received is 815 MHz. Figure 4 The measurement results of the radiation characteristics of the antenna device without the parasitic antenna element 102 according to the first exemplary embodiment are shown. Figure 5 The measurement results of the radiation characteristics of the antenna device 100 according to the first exemplary embodiment are shown. Note that Figure 5 is a measurement result using the parasitic antenna element 102 having a length of 135 mm. Figure 4 and Figure 5 The antenna efficiency of the antenna device 100 including the parasitic antenna element 102 is -1.6 dB, while the antenna efficiency of the antenna device without the parasitic antenna element 102 is -3.4 dB. Therefore, it can be understood that by providing the parasitic antenna element 102, the intensity of the vertically polarized wave can be increased, and the antenna efficiency can be further improved.

[0045] According to the antenna device 100 and wireless communication device 200 according to the first exemplary embodiment described above, a parasitic antenna element 102 having a vertical element portion arranged perpendicular to the ground is provided near the end of the feed antenna element 101, thereby increasing the intensity of vertically polarized waves. As a result, the antenna efficiency of the antenna device 100 and wireless communication device 200 can be improved. Furthermore, the length of the parasitic antenna element 102, which serves as a reflective element, can be shortened to less than half the wavelength of the radio waves to be transmitted and received. This makes it possible to suppress the increase in size of the antenna device 100 and wireless communication device 200. Furthermore, since the feed antenna element 101 and the parasitic antenna element 102 are arranged in close proximity, no additional noise countermeasures are required. Consequently, a compact antenna device and wireless communication device capable of transmitting and receiving vertically polarized waves without requiring additional noise countermeasures can be provided.

[0046] Second exemplary embodiment

[0047] Next, we will refer to Figures 6 to 8 A second exemplary embodiment of the present invention is described. Figure 6 and Figure 7 are diagrams each showing an example of an antenna device 300 according to a second exemplary embodiment of the present invention. Figure 8 The measurement results of the radiation characteristics of the antenna device 300 according to the second exemplary embodiment are shown. Note that the second exemplary embodiment differs from the first exemplary embodiment only in the configuration of the parasitic antenna element 302 in the antenna device 300. Therefore, in the second exemplary embodiment, the same reference numerals are assigned to the same configurations as those of the first exemplary embodiment, and their descriptions are omitted.

[0048] Parasitic antenna element 302 is a flat, U-shaped element. Specifically, parasitic antenna element 302 includes a first element portion 302A, a second element portion 302B, and a third element portion 302C. First element portion 302A and second element portion 302B are two opposing sides of the flat, U-shaped element and are arranged parallel to element portion 101A of feed antenna element 101, which is parallel to the ground. First element portion 302A is arranged closer to substrate 201 than second element portion 302B and faces element portion 101A of feed antenna element 101. Third element portion 302C connects the two opposing sides of the flat, U-shaped element and is a vertical element portion of parasitic antenna element 302. That is, first element portion 302A and second element portion 302B are arranged parallel to the X-axis, and third element portion 302C is arranged parallel to the Z-axis. One end of the third element portion 302C, serving as a vertical element portion, is arranged near the other end of the feeding antenna element (the end on the side opposite to the feeding end). Specifically, the end of the third element portion 302C on the feeding antenna element 101 side is arranged a predetermined distance away from the edge of the substrate 201. The end of the third element portion 302C is arranged near the end of the element portion 101A of the feeding antenna element 101 (on the side opposite to the end of the element portion 101A connected to the element portion 101B). Note that the distance between the end of the third element portion 302C and the other end of the feeding antenna element 101 (the end on the side opposite to the feeding end) is such that a high-frequency current can be excited in the parasitic antenna element 302 by feeding the feeding antenna element 101.

[0049] Parasitic antenna element 302 is formed of a linear or elongated plate-shaped conductor such as copper, brass, or aluminum. Parasitic antenna element 302 can be formed as a conductor pattern of a printed wiring board. Note that the resonant frequency of parasitic antenna element 302 matches the resonant frequency of feed antenna element 101.

[0050] In the first exemplary embodiment, the length of parasitic antenna element 102 is less than half the wavelength of the radio waves to be transmitted and received. However, since parasitic antenna element 302 according to the second exemplary embodiment has a flat U-shape, the length of third element portion 302C (vertical element portion) can be shorter than the length of parasitic antenna element 102. In the second exemplary embodiment, for example, when the frequency of the radio waves to be transmitted and received is 815 MHz, the length of third element portion 302C (vertical element portion) is, for example, 90 mm. Note that the length (height) of third element portion 302C is not limited to the above length because it depends on the wavelength of the target radio waves.

[0051] Figure 7 The operation of the antenna device 300 according to the second exemplary embodiment is shown. Figure 7 In FIG, the current flowing through the ground layer 202 is indicated by a solid arrow, the current flowing through the feed antenna element 101 is indicated by a dashed arrow, and the current induced in the parasitic antenna element 302 is indicated by a dashed arrow. Figure 7 As shown, the operation of the antenna device 300 according to the second exemplary embodiment is similar to Figure 2 The operation of the antenna device 100 according to the first exemplary embodiment shown is the same, and thus a description thereof is omitted.

[0052] Next, refer to Figure 8 , the radiation characteristics of the vertically polarized wave of the antenna device 300 according to the second exemplary embodiment will be described. Note that, Figure 8 is a measurement result using the parasitic antenna element 302, wherein the parasitic antenna element 302 has a third element portion 302C (as a vertical element portion) of 90 mm in length. In addition, Figure 8 Shows the measurement results of the radiation characteristics when the frequency of the radio waves to be transmitted and received is 815 MHz. Figure 5 and Figure 8 , the antenna efficiency of the antenna device 100 according to the first exemplary embodiment is -1.6 dB, while the antenna efficiency of the antenna device 300 according to the second exemplary embodiment is -1.5 dB. Therefore, it should be understood that, similar to the antenna device 100 according to the first exemplary embodiment, the intensity of the vertically polarized wave can be increased and the antenna efficiency can be further improved in the antenna device 300 according to the second exemplary embodiment.

[0053] According to the antenna device 300 and the wireless communication device 200 according to the second exemplary embodiment that have been described above, not only can effects equivalent to those of the antenna device 100 according to the first exemplary embodiment be obtained, but also, because the parasitic antenna element 302 has a flattened U-shape, the height of the parasitic antenna element 302 of the antenna device 300 can be further reduced. This makes it possible to further reduce the height of the antenna device 300 and the wireless communication device 200.

[0054] Third exemplary embodiment

[0055] Next, we will refer to Figures 9 to 11 A third exemplary embodiment of the present invention is described. Figure 9 and Figure 10 are diagrams each showing an example of an antenna device 400 according to a third exemplary embodiment of the present invention. Figure 11The measurement results of the radiation characteristics of antenna device 400 according to the third exemplary embodiment are shown. Note that the third exemplary embodiment differs from the first exemplary embodiment only in the configuration of parasitic antenna element 402 in antenna device 400. Therefore, in the third exemplary embodiment, the same reference numerals are assigned to the same configurations as those of the first exemplary embodiment, and description thereof is omitted.

[0056] Parasitic antenna element 402 includes not only components parallel to the X-axis and Z-axis, but also components parallel to the Y-axis. In other words, parasitic antenna element 402 has a three-dimensional shape. Specifically, parasitic antenna element 402 includes a first component portion 402A, a second component portion 402B, a third component portion 402C, a fourth component portion 402D, and a fifth component portion 402E. First component portion 402A, second component portion 402B, third component portion 402C, fourth component portion 402D, and fifth component portion 402E are electrically connected in this order. In addition, first component portion 402A, second component portion 402B, third component portion 402C, fourth component portion 402D, and fifth component portion 402E are connected to each other's ends so that the angle formed by their ends is at right angles to each other. First component portion 402A, second component portion 402B, fourth component portion 402D, and fifth component portion 402E are parallel component portions arranged parallel to the ground. Third element portion 402C is a vertical element portion arranged perpendicular to the ground. First element portion 402A is arranged at a position facing element portion 101A of feed antenna element 101 and is arranged near feed antenna element 101. Second element portion 402B and fourth element portion 402D are connected to the end of third element portion 402C, which is a vertical element portion, so that the angle formed by third element portion 402C is perpendicular to each other.

[0057] More specifically, first element portion 402A and fifth element portion 402E are arranged parallel to the X-axis. Second element portion 402B and fourth element portion 402D are arranged parallel to the Y-axis. Third element portion 402C is arranged parallel to the Z-axis. First element portion 402A and fifth element portion 402E are opposite each other, and second element portion 402B and fourth element portion 402D are opposite each other. First element portion 402A and second element portion 402B are arranged on a side closer to substrate 201 than fourth element portion 402D and fifth element portion 402E. First element portion 402A and fifth element portion 402E are arranged at substantially the same position relative to substrate 201 in the Y-axis direction. First element portion 402A is arranged so as to face element portion 101A of feed antenna element 101. Second element portion 402B is connected to an end of first element portion 402A that faces the other end of feed antenna element 101 (the end on the side opposite the feed end). The third element portion 402C is connected to the end of the second element portion 402B on the side opposite to the end connected to the first element portion 402A, and extends parallel to the Z-axis in a direction away from the substrate 201. The fourth element portion 402D is connected to the end of the third element portion 402C on the side opposite to the end of the third element portion 402C on the substrate 201 side. The fifth element portion 402E is connected to the end of the fourth element portion 402D on the side opposite to the end connected to the third element portion 402C. Furthermore, the second element portion 402B extends from the end of the first element portion 402A in a direction projecting toward the surface side of the substrate 201 where the ground layer 202, the supply source 203, the feed antenna element 101, and the like are provided. Hereinafter, the surface of the substrate 201 where the ground layer 202, the supply source 203, and the feed antenna element 101 are provided is referred to as the surface of the substrate 201. Similarly, the fourth element portion 402D extends from the end of the fifth element portion 402E in a direction protruding toward the surface side of the substrate 201. That is, the second element portion 402B, the third element portion 402C, and the fourth element portion 402D are arranged at positions away from the surface of the substrate 201 in the Y-axis direction.

[0058] First element portion 402A is arranged to be separated from the edge of substrate 201 by a predetermined distance. First element portion 402A is arranged near element portion 101A of feeding antenna element 101 so as to face element portion 101A. Note that the distance between first element portion 402A and element portion 101A of feeding antenna element 101 is such a distance that a high-frequency current can be excited in parasitic antenna element 402 by feeding feeding antenna element 101.

[0059] The parasitic antenna element 402 is formed of a linear or elongated plate-like conductor such as copper, brass, or aluminum, etc. Note that the resonant frequency of the parasitic antenna element 402 coincides with the resonant frequency of the feeding antenna element 101 .

[0060] In the first exemplary embodiment, the length of parasitic antenna element 102 is less than half the wavelength of the radio waves to be transmitted and received. However, since parasitic antenna element 402 according to the third exemplary embodiment has a three-dimensional shape with multiple element portions connected, the length of third element portion 402C (vertical element portion) is shorter than the length of parasitic antenna element 102. In the third exemplary embodiment, for example, when the frequency of the radio waves to be transmitted and received is 815 MHz, the length of third element portion 402C (vertical element portion) is, for example, 50 mm. Note that the length (height) of third element portion 402C is not limited to the above length because it depends on the wavelength of the target radio waves.

[0061] Figure 10 The operation of the antenna device 400 according to the third exemplary embodiment is shown. Figure 10 In FIG, the current flowing through the ground layer 202 is indicated by a solid arrow, the current flowing through the feed antenna element 101 is indicated by a dashed arrow, and the current induced in the parasitic antenna element 402 is indicated by a dashed arrow. Figure 10 As shown, the operation of the antenna device 400 according to the third exemplary embodiment is similar to Figure 2 The operation of the antenna device 100 according to the first exemplary embodiment shown is the same, and thus a description thereof is omitted.

[0062] Next, refer to Figure 11 , the radiation characteristics of the vertically polarized wave of the antenna device 400 according to the third exemplary embodiment will be described. Note that, Figure 11 is a measurement result using the parasitic antenna element 402, wherein the parasitic antenna element 402 has a third element portion 402C as a vertical element portion with a length of 50 mm. In addition, Figure 11 Shows the measurement results of the radiation characteristics when the frequency of the radio waves to be transmitted and received is 815 MHz. Figure 5 and Figure 11 , the antenna efficiency of antenna device 100 according to the first exemplary embodiment is -1.6 dB, while the antenna efficiency of antenna device 400 according to the third exemplary embodiment is -2.9 dB. Therefore, it can be seen that, similar to antenna device 100 according to the first exemplary embodiment, antenna device 400 according to the third exemplary embodiment can also increase the intensity of vertically polarized waves and further improve antenna efficiency.

[0063] According to the antenna device 400 and the wireless communication device 200 according to the third exemplary embodiment that have been described above, not only can effects equivalent to those of the antenna device 100 according to the first exemplary embodiment be achieved, but also, because the parasitic antenna element 402 has a three-dimensional shape, the height of the parasitic antenna element 402 of the antenna device 400 can be further reduced. This makes it possible to further reduce the height of the antenna device 400 and the wireless communication device 200.

[0064] Although the present invention has been described above with reference to exemplary embodiments, the present invention is not limited thereto. Various modifications can be made to the structure and details of the present invention within the scope of the present invention, which can be understood by those skilled in the art.

[0065] This application claims the benefit of Japanese Patent Application No. 2020-075850, filed on April 22, 2020, the disclosure of which is incorporated herein by reference in its entirety.

[0066] Industrial applicability

[0067] An antenna device and a wireless communication device that are small in size and capable of transmitting and receiving vertically polarized waves without requiring additional noise countermeasures can be provided.

[0068] Reference Signs List

[0069] 100, 300, 400 antenna units

[0070] 101 Feed Antenna Element

[0071] 101A, 101B components

[0072] 102 parasitic antenna element (vertical element part)

[0073] 302, 402 parasitic antenna elements

[0074] 302A First component part

[0075] 302B Second component part

[0076] 302C Third component part (vertical component part)

[0077] 402A First component part (parallel component part)

[0078] 402B Second component part (parallel component part)

[0079] 402C Third component part (vertical component part)

[0080] 402D Fourth component part (parallel component part)

[0081] 402E Fifth Component Part (Parallel Component Part)

[0082] 200 Wireless Communication Device

[0083] 201 substrate

[0084] 202 ground layer

[0085] 203 Supply Source

Claims

1. An antenna device, comprising: a feed antenna element configured to be electrically connected at one end to a supply source configured to supply a wireless communication signal, the feed antenna element including an element portion parallel to the ground; as well as a parasitic antenna element including a vertical element portion arranged perpendicular to the ground, the parasitic antenna element being arranged to be separated from the other end of the feed antenna element by a predetermined distance, The parasitic antenna element is a flat U-shaped element. Two opposite sides of the lying U-shape are arranged parallel to the element portion of the feed antenna element parallel to the ground, One side connecting two opposite sides of the lying U-shape is the vertical element portion, and One end of the vertical element portion is arranged to be separated from the other end of the feeding antenna element by the predetermined distance.

2. An antenna device, comprising: a feed antenna element configured to be electrically connected at one end to a supply source configured to supply a wireless communication signal, the feed antenna element including an element portion parallel to the ground; as well as a parasitic antenna element including a vertical element portion arranged perpendicular to the ground, the parasitic antenna element being arranged to be separated from the other end of the feed antenna element by a predetermined distance, The parasitic antenna element comprises two parallel element components arranged parallel to the ground, wherein each of the two parallel element components comprises a plurality of parallel element parts. the plurality of parallel element portions are connected to each other's ends in such a manner that at least two of the plurality of parallel element portions form a right angle, The two parallel element parts are each connected to each end of the vertical element part at a right angle to the respective angle formed by the vertical element part, and One of the plurality of parallel element portions of one of the two parallel element parts is arranged parallel to the element portion of the feeding antenna element parallel to the ground at a position facing the feeding antenna element and is arranged apart from the feeding antenna element by the predetermined distance.

3. A wireless communication device, comprising: a substrate on which a ground layer having a reference potential and a supply source for supplying a wireless communication signal are formed; as well as The antenna device according to claim 1 or 2.

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