Antenna unit and communication device

Abstract

An antenna unit comprising a first antenna unit (10) and a second antenna unit (20), each transmitting or receiving wireless signals, and a ground unit (30) electrically connected to each of the first antenna unit (10) and the second antenna unit (20) and comprising a portion located between the first antenna unit (10) and the second antenna unit (20). A through-hole resonating at a given frequency is provided at the location of the ground unit (30) between the first antenna unit (10) and the second antenna unit (20).

Description

Technical Field

[0001] The present invention relates to an antenna element comprising a plurality of antennas for wireless communication and a communication device comprising the antenna element. Background Technology

[0002] In communication devices that perform wireless communication, some devices include multiple antennas to achieve compatibility with multiple standards or improve communication quality. For example, communication devices that include an antenna compatible with the Bluetooth (registered trademark) standard and another antenna compatible with the Wireless Local Area Network (LAN) standard are known. Furthermore, in Multiple-Input Multiple-Output (MIMO) technology, multiple antennas are used for a single wireless communication connection. Summary of the Invention

[0003] [Technical Issues]

[0004] In the communication devices described above, where multiple antennas transmit and receive radio waves in overlapping frequency bands, mutual interference can sometimes occur between the antennas, degrading communication performance. To prevent this interference and enhance isolation between antennas, it is conceivable to increase the physical distance between them. However, increasing the physical distance between antennas necessitates increasing the size of the communication device or introduces structural limitations. In particular, from a noise reduction perspective, when it is desirable to position antennas isolated from any other electronic components (connectors, etc.), or in similar situations, it is sometimes difficult to position antennas isolated from any other electronic components and to arrange them in a way that isolates them from each other.

[0005] In view of the situation described above, the present invention was made, and one of the objects of the present invention is to provide an antenna element and communication device that can suppress interference between antennas in a relatively space-saving manner.

[0006] [Solution to the problem]

[0007] An antenna element according to one embodiment of the present invention includes a first antenna portion and a second antenna portion that separately transmit or receive wireless signals, and a ground portion electrically connected to each of the first antenna portion and the second antenna portion and including a portion located between the first antenna portion and the second antenna portion. A through-hole resonating at a given frequency is provided at the location of the ground portion between the first antenna portion and the second antenna portion.

[0008] A communication device according to one embodiment of the present invention includes an antenna unit comprising a first antenna portion and a second antenna portion for separately transmitting or receiving wireless signals, and a ground portion electrically connected to each of the first and second antenna portions and including a portion located between the first and second antenna portions. A through-hole resonating at a given frequency is provided at the location of the ground portion between the first and second antenna portions, and the communication device performs wireless communication with other communication devices through the first and second antenna portions. Attached Figure Description

[0009] Figure 1 This is a top view depicting the shape of an antenna element according to an embodiment of the present invention.

[0010] Figure 2A This is a view illustrating the resonance mode of an antenna element according to an embodiment of the present invention.

[0011] Figure 2B This is a view illustrating another resonance mode of an antenna element according to an embodiment of the present invention.

[0012] Figure 3 This is a view illustrating the isolation performance between antennas in an antenna element according to an embodiment of the present invention.

[0013] Figure 4 It is a perspective view depicting the shape of an antenna element according to a first variation of the present invention.

[0014] Figure 5 It is a perspective view depicting the shape of an antenna element according to a second variation of the present invention.

[0015] Figure 6 This is a perspective view depicting the shape of an antenna element according to a third variation of the present invention. Detailed Implementation

[0016] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0017] Figure 1 This is a top view depicting the shape of antenna element 1 according to an embodiment of the present invention. According to an embodiment of the present invention, antenna element 1 is arranged inside a communication device. The communication device can be any of various types of devices performing wireless communication, such as personal computers, stationary game consoles, portable game consoles, smartphones, and tablet computers.

[0018] Antenna element 1 is generally composed of a single conductor. More specifically, antenna element 1 is formed by processing a single metal component in the form of a plate. Antenna element 1 includes a first antenna portion 10, a second antenna portion 20, and a ground portion 30. In the following description, the shape and positional relationship of the first antenna portion 10, the second antenna portion 20, and the ground portion 30, as well as the function of the components, are described in a top view.

[0019] The first antenna portion 10 and the second antenna portion 20 independently transmit and / or receive wireless signals (electromagnetic waves). The communication device according to this embodiment uses the first antenna portion 10 and the second antenna portion 20 to perform wireless communication with some other communication devices. In the following description, the frequency band of the wireless signal to be used as the target for transmission and reception of each of the first antenna portions 10 and 20 is referred to as the target frequency band. It is assumed that the target frequency band of the first antenna portion 10 and the target frequency band of the second antenna portion 20 at least partially overlap with each other. For example, one of the first antenna portion 10 and the second antenna portion 20 can be used for wireless local area network communication based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, while the other of the first and second antenna portions can be used for Bluetooth communication. Alternatively, both the first antenna portion 10 and the second antenna portion 20 can be used for communication via the same standard (e.g., wireless local area network or Bluetooth) based on technologies such as MIMO. In this embodiment, it is assumed that the target frequency bands of the first antenna portion 10 and the second antenna portion 20 are substantially consistent with each other and are a frequency band close to 2.4 GHz.

[0020] The first antenna section 10 has an overall approximately F-shaped form and functions as an inverted F-shaped antenna. The shape and dimensions of the first antenna section 10 are determined such that resonance occurs at a frequency within the target frequency band of the first antenna section 10. In the following description, the resonance occurring in the first antenna section 10 is referred to as the first resonance.

[0021] Specifically, the first antenna portion 10 includes a main body portion 11, a feed portion 12, and a short-circuit portion 13. The main body portion 11 is shaped to extend in the upward and downward directions and its base end is connected to the end of the short-circuit portion 13, and the end of the main body portion 11 is an open end. The feed portion 12 is shaped to extend in the left and right directions and its base end provides a feed point P1 for the first antenna portion 10. The feed portion 12 is connected to the main body portion 11 at its end near the base end between the end of the main body portion 11 and the base end. The short-circuit portion 13 is shaped to extend in the left-right direction, parallel to the feed portion 12, and its base end is connected to the upper end of the ground portion 30, and its end is connected to the base end of the main body portion 11.

[0022] like Figure 1As shown, the second antenna portion 20 is arranged symmetrically with respect to the axis of symmetry given by the center line in the left-right direction of the antenna element 1 with respect to the first antenna portion 10. Specifically, the second antenna portion 20 has a shape substantially the same as the first antenna portion 10 and is arranged in directions opposite to the right and left directions of the first antenna portion 10. Furthermore, the first antenna portion 10 and the second antenna portion 20 are arranged in an arrangement such that they are opposite each other along the left-right direction of the antenna element 1. Additionally, the first antenna portion 10 and the second antenna portion 20 are arranged at positions that are substantially equidistant from the center line in the left-right direction of the antenna element 1. Furthermore, as... Figure 1 As shown, the feed point P2 of the second antenna section 20 is also arranged symmetrically with respect to the axis of symmetry given by the center line in the left-right direction of the antenna element 1, and is positioned symmetrically with respect to the feed point P1 of the first antenna section 10. Therefore, the second antenna section 20 resonates in a target frequency band substantially equal to that of the first antenna section 10. In the following description, the resonance occurring in the second antenna section 20 is referred to as the second resonance.

[0023] Specifically, the second antenna portion 20 includes a main body portion 21, a power supply portion 22, and a short-circuit portion 23. The main body portion 21 is shaped to extend in the vertical direction and its base end is connected to the end of the short-circuit portion 23, and the end of the main body portion 21 is an open end. The power supply portion 22 is shaped to extend in the horizontal direction, and the power supply point P2 of the second antenna portion 20 is arranged at the base end of the power supply portion 22. The power supply portion 22 is connected to the main body portion 21 at its end near the base end, between the end of the main body portion 21 and the base end. The short-circuit portion 23 is shaped to extend in the horizontal direction, parallel to the power supply portion 22, and its base end is connected to the upper end of the ground portion 30, and its end is connected to the base end of the main body portion 21.

[0024] As described above, the second antenna portion 20 is arranged symmetrically with respect to the first antenna portion 10. Therefore, the directivity of the first antenna portion 10 and the second antenna portion 20 is also approximately symmetrical. Consequently, the correlation coefficient between the first antenna portion 10 and the second antenna portion 20 in the target frequency band can be suppressed to a low level.

[0025] The grounding portion 30 is electrically connected to the first antenna portion 10 and the second antenna portion 20 by being integrally formed with them, and serves as the ground for the antenna. The grounding portion 30 is shaped such that it extends integrally in the vertical direction, and its upper end is connected to the short-circuit portion 13 of the first antenna portion 10 and the short-circuit portion 23 of the second antenna portion 20.

[0026] More specifically, the grounding portion 30 includes a middle portion 31 located between the first antenna portion 10 and the second antenna portion 20, and an outer edge portion 32 extending along the lower side of the antenna element 1. It should be noted that the grounding portion 30 has a left-right symmetrical shape with respect to the center line in the left-right direction of the antenna element 1. Therefore, the entire antenna element 1 is left-right symmetrical with respect to its center line.

[0027] The slot 33 is substantially formed in the middle of the grounding portion 30 and extends through the through-hole of the antenna element 1 in the form of a flat plate. The slot 33 is arranged between the first antenna portion 10 and the second antenna portion 20. Specifically, in this embodiment, the slot 33 is shaped such that it extends approximately along the center line of the antenna element 1 in the leftward direction (the direction in which the first antenna portion 10 and the second antenna portion 20 are arranged) in both upward and downward directions (in other words, in directions intersecting the direction in which the first antenna portion 10 and the second antenna portion 20 are arranged). Furthermore, the slot 33 is arranged such that the distance from the slot 33 to the feed point P1 and the distance from the slot 33 to the feed point P2 are equal to each other. In addition, as shown in the top view, the slot 33 is formed at a position that overlaps with a portion of the straight line connecting the feed point P1 of the first antenna portion 10 and the feed point P2 of the second antenna portion 20.

[0028] The slot 33 includes a generally rectangular extension 33a extending in the vertical direction and a wide portion 33b connected to one end of the extension 33a and having a width greater than that of the extension 33a. Therefore, the slot 33 has an overall inverted T-shape. It should be noted that the slot 33 is also symmetrical about the center line in the left-right direction of the antenna element 1.

[0029] Due to the presence of the hollow slot 33, resonance occurs not only at the first antenna portion 10 and the second antenna portion 20, but also at the ground portion 30 along the slot 33. In the following description, the resonance occurring along the slot 33 in the ground portion 30 is referred to as slot resonance. The frequency band of the slot resonance depends on the length of the perimeter of the slot 33. In this embodiment, the size and shape of the slot 33 are determined such that the frequency band of the slot resonance overlaps with at least a portion of the target frequency band of the first antenna portion 10 and the second antenna portion 20. In other words, the first resonance, the second resonance, and the slot resonance occur in frequency bands that overlap with each other. In the following description, the frequency band shared by the three resonances is referred to as the resonant frequency band.

[0030] The periphery of slot 33 must have a length at least equal to or longer than half the wavelength of the electromagnetic wave corresponding to the resonant frequency band. To ensure this periphery length, a wide portion 33b is formed at one end of slot 33. It should be noted that, to avoid interference with the first antenna portion 10 and the second antenna portion 20, the wide portion 33b is formed at one of the opposite ends of slot 33 extending in the vertical direction, located on the side away from the feed points P1 and P2.

[0031] Furthermore, the slot resonance in this resonant band occurs in a phase offset by 90 degrees from the first resonance. Therefore, the first resonance and the slot resonance are related in that their nodes and bands are interchanged. From this relationship just described, the slot resonance acts as a counter-resonance that cancels out the effect of the first resonance on the second antenna section 20.

[0032] Figure 2A and 2B It is a view depicting the relationship between the first resonance and the slot resonance, and a simulation result indicating the current distribution that occurs when a signal is input to the feed point P1 of the first antenna section 10. Figure 2A The current distribution generated by the first resonance is depicted, while Figure 2B Depicting in relation to Figure 2A The current distribution at a 90-degree phase shift. For example... Figure 2A and 2B As shown, at the moment when current is generated by the first resonance at the first antenna section 10, no significant current is generated around slot 33. Conversely, at another moment when current is generated by slot resonance at slot 33, no significant current is generated at the first antenna section 10.

[0033] As described above, slot 33 is positioned precisely at the midpoint between the first antenna section 10 and the second antenna section 20, making their distances to the two antennas equidistant. Therefore, similar to the first resonance described above, the slot resonance is an oscillation with a phase offset of 90 degrees from the second resonance. Thus, the slot resonance acts as a counter-resonance to cancel out the effect of the second resonance on the first antenna section 10. Specifically, when a signal is input to the feed point P2, a resonant resonant occurs... Figure 2A and 2B The current distribution depicted in the image is a reversed current distribution.

[0034] As described above, interference between the two antenna sections can be suppressed by slot resonance generated by slot 33. Figure 3 This is a graph showing the results of a study simulating the isolation performance between antennas of antenna element 1 according to this embodiment. The horizontal axis of the graph represents frequency, and the vertical axis represents the isolation value, and the isolation performance between antennas improves as the value decreases. As shown in the graph, it can be recognized that, according to this embodiment, isolation is improved in the resonant frequency band (the band close to 2.4 GHz).

[0035] For the antenna unit 1 according to the above embodiment, since the slot 33 generates a resonance with a resonant phase offset of 90 degrees from that generated by each antenna part, the isolation performance between the two antenna parts can be improved without having to arrange the two antenna parts in positions physically separated from each other. Furthermore, for the antenna unit 1 according to this embodiment, since the first antenna part 10, the second antenna part 20, and the ground part 30 are formed into a single component by a single conductive member, the structure is not complex and production costs can be suppressed.

[0036] It should be noted that the embodiments of the present invention are not limited to the embodiments described above. For example, the shape of the antenna element 1 described above is merely an example, and the antenna element 1 can have various shapes only when the ground portion 30 having the slot 33 is arranged between the first antenna portion 10 and the second antenna portion 20.

[0037] The following describes several variations of antenna element 1. Figure 4 This is a perspective view depicting the shape of antenna element 1 according to a first variant. In the example of this figure, the first antenna portion 10 and the second antenna portion 20 differ in shape from each other. Figure 1 Therefore, antenna element 1 is configured to resonate in multiple frequency bands.

[0038] Specifically, in this variant, a slit 14 with a tortuous shape is formed between the feed portion 12 and the short-circuit portion 13 of the first antenna portion 10. With this configuration just described, the first antenna portion 10 resonates in the first target frequency band via the body portion 11 and in the second target frequency band via the slit 14. Therefore, the first antenna portion 10 transmits and receives radio signals in two different target frequency bands. The second antenna portion 20 has a structure that is approximately symmetrical to the first antenna portion 10, and thus resonates in the first target frequency band via the body portion 21 and in the second target frequency band via the slit 24.

[0039] Similarly, in this variant, the isolation performance between the first antenna section 10 and the second antenna section 20 can be improved because slot 33 generates slot resonance. However, slot 33 improves isolation performance by generating slot resonance targeting a resonant frequency band, which depends on the size and shape of slot 33. Therefore, preferably, the size and shape of slot 33 are determined based on the frequency band from which the isolation performance between the first target frequency band and the second target frequency band is more desired to be improved.

[0040] In the descriptions so far, it has been assumed that antenna element 1 is formed of a metal component in the form of a flat plate, and that the first antenna portion 10, the second antenna portion 20, and the ground portion 30 are all contained in the same plane. However, the shape of antenna element 1 is not limited to this. Figure 5The shape of antenna element 1 according to the second variant is depicted. In the example in this figure, antenna element 1 is shaped such that the metal member with the same shape as antenna element 1 according to the first variant is bent inward along a centerline extending in its left-right direction.

[0041] at the same time, Figure 6 The shape of antenna element 1 according to the third variant is depicted. Antenna element 1 according to this variant is shaped such that it bends inward along straight lines extending in the upward and downward directions, similar to those in the second variant. Specifically, antenna element 1 according to the third variant is shaped such that the plate-shaped metal member bends along two straight lines, including the straight line between the first antenna portion 10 and the slot 33 and another straight line between the second antenna portion 20 and the slot 33.

[0042] In this way, antenna element 1 does not need to have a planar shape, and the isolation between antennas can only be improved when the slot 33 for generating a resonance that is 90 degrees out of phase with each of the first and second resonances is formed in the ground portion 30.

[0043] Furthermore, although it was assumed in the preceding description that antenna element 1 is formed from a single metal plate, antenna element 1 can be formed in other ways as a metal foil, such as copper foil on the surface of a printed circuit board. In this case, since the dielectric is arranged in the slot 33, the electrical length of the periphery of the slot 33 can be greater than its physical length. Therefore, compared to the alternative case where the interior of the slot 33 is hollow, the periphery length of the slot 33 resonating in the resonant frequency band can be made shorter.

[0044] Furthermore, although it is assumed in the preceding description that the entire antenna element 1, including the first antenna portion 10, the second antenna portion 20, and the ground portion 30, is formed from a single conductive member, the antenna element 1 can be formed in other ways by connecting multiple conductive members. Furthermore, when the antenna element 1 is formed on a printed circuit board, it can be formed such that it extends across multiple printed circuit board layers electrically connected to each other. Furthermore, although it is assumed in the preceding description that the first antenna portion 10 and the second antenna portion 20 have identical shapes, the first antenna portion 10 and the second antenna portion 20 can have different shapes corresponding to their respective target frequency bands. Similarly, in this case, by providing a slot 33 at a location substantially equidistant from the feed point P1 of the first antenna portion 10 and the feed point P2 of the second antenna portion 20 to generate a resonance with a 90-degree phase offset from the resonance of the first antenna portion 10 and the second antenna portion 20, the isolation performance between the two antennas can be improved.

[0045] [List of reference numerals]

[0046] 1: Antenna Unit

[0047] 10: First antenna section

[0048] 20: The second day's sky section

[0049] 11, 21: Main body

[0050] 12, 22: Power supply section

[0051] 13, 23: Short circuit section

[0052] 30: Grounding part

[0053] 31: Middle section

[0054] 32: Outer edge portion

[0055] 33: slot

[0056] 33a: Extension

[0057] 33b: Width portion

Claims

1. An antenna element, comprising: A first antenna section and a second antenna section that transmit or receive wireless signals independently; and The grounding portion is electrically connected to each of the first antenna portion and the second antenna portion, and includes a portion located between the first antenna portion and the second antenna portion, wherein... A through-hole resonates at a given frequency at the location of the ground portion between the first antenna section and the second antenna section. The through-hole includes: (i) an extension portion extending along the direction in which the first antenna portion and the second antenna portion are arranged, and (ii) a wide portion connected to one end of the extension portion and having a width greater than the width of the extension portion. The through hole has a T-shape overall.

2. The antenna element according to claim 1, wherein When viewed from above, the via is formed at a location that overlaps with a portion of the straight line connecting the feed points of the first antenna portion and the feed points of the second antenna portion.

3. The antenna element according to claim 1 or 2, wherein Each of the first and second antenna sections has approximately the same shape, with the second antenna section arranged in a direction that reverses to the right and left of the first antenna section.

4. The antenna element according to claim 3, wherein Each of the first and second antenna sections has an F-shape and is used as an inverted F-shaped antenna.

5. The antenna element according to any one of the preceding claims, wherein The second antenna section is linearly symmetrical to the first antenna section with respect to the axis of symmetry given by the center line in the left-right direction of the antenna element.

6. The antenna element according to claim 5, wherein The first antenna section and the second antenna section are arranged at equal distances from each other along the center line in the left-right direction of the antenna element.

7. The antenna element according to any one of claims 1 to 6, wherein The first antenna section, the second antenna section, and the grounding section are formed by a single conductive component in the form of a plate.

8. The antenna element according to any one of claims 1 to 7, wherein The extended portion has a rectangular shape.

9. A communication device comprising an antenna element according to any one of the preceding claims.

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