Antenna unit

Abstract

An antenna unit includes an antenna capable of transmitting and receiving radio waves of a predetermined frequency band, the antenna includes a conductor layer formed on a substrate extending in a first direction, and a first antenna and a second antenna capable of transmitting and receiving polarized waves different from each other, the first antenna is supplied with power from one end and the other end is open, and the second antenna is supplied with power from one end and the other end is open. The first antenna and the second antenna are formed in a central region of the substrate in the first direction.

Description

Technical Field

[0001] The present invention relates to an antenna element having an antenna capable of transmitting and receiving radio waves in a specified frequency band. Background Technology

[0002] Traditionally, antennas have been used for transmitting and receiving radio waves. As a technology related to such antennas, there is, for example, the antenna module described in Patent Document 1.

[0003] The antenna module described in Patent Document 1 (equivalent to the "antenna element" in this application) has a first antenna and a second antenna. These antennas are configured in a so-called inverted F-shape, and the power supply unit is electrically connected to the power-received unit via capacitive coupling.

[0004] Prior technology documents

[0005] Patent documents

[0006] Patent document 1: Japanese Patent Application Publication No. 2023-104765.

[0007] The problem that the invention aims to solve

[0008] In the antenna module described in Patent Document 1, the first antenna and the second antenna are positioned at a 90-degree angle to each other. In this case, in order to transmit and receive waves with different polarizations, a substrate with an aspect ratio close to 1 is required. Therefore, the substrate of the antenna module described in Patent Document 1 is square in shape, leaving room for improvement in substrate miniaturization.

[0009] Therefore, miniaturized antenna elements are required. Summary of the Invention

[0010] Technical means for solving the problem

[0011] The antenna unit involved in this invention is characterized by having an antenna capable of transmitting and receiving radio waves in a specified frequency band. The antenna has a first antenna and a second antenna, which are formed on a conductor layer of a substrate extending along a first direction and are capable of transmitting and receiving waves with different polarizations. The first antenna is powered from one end and open at the other end, and the second antenna is powered from one end and electrically connected to a ground region at the other end. The first antenna and the second antenna are formed in a central region of the substrate along the first direction.

[0012] With this configuration, the first antenna is formed in the central region of the substrate along the first direction, powered from one end and open at the other, thus enabling the transmission and reception of polarized waves orthogonal to the first direction. Similarly, the second antenna is formed in the central region of the substrate along the first direction, powered from one end and electrically connected to a ground region at the other end, thus enabling the transmission and reception of polarized waves in the first direction. Furthermore, in this configuration, the length of the substrate in the direction orthogonal to the first direction is not particularly limited, thus allowing for substrate miniaturization. Attached Figure Description

[0013] Figure 1 This is a top view of the antenna unit.

[0014] Figure 2 This is a magnified view of the first celestial body.

[0015] Figure 3 This is a magnified view of the second day's horizon.

[0016] Figure 4 This is a top view of the antenna element after the antenna position has been changed. Detailed Implementation

[0017] The antenna element disclosed herein includes an antenna capable of transmitting and receiving radio waves in a specified frequency band, and capable of transmitting and receiving waves with different polarizations. Hereinafter, antenna element 1 of this embodiment will be described. However, antenna element 1 is not limited to the following embodiment, and various modifications can be made without departing from its spirit.

[0018] Figure 1 This is a top view of antenna element 1. Figure 2 This is an enlarged view of the first antenna 11. Figure 3 This is a magnified view of Line 12 on the second day. (Example) Figure 1 As shown, the antenna unit 1 includes an antenna 10, a removal section 20, an impedance adjustment section 30, and a control section 40.

[0019] Antenna 10 has a first antenna 11 and a second antenna 12. Antenna 10 is capable of receiving radio waves propagating in the air and converting them into electrical signals, transmitting the electrical signals to the control unit 40, and enabling radio waves superimposed with the electrical signals output from the control unit 40 to propagate in the air.

[0020] Antenna 10 is formed on a conductor layer of substrate 2 extending along a first direction. In this embodiment, substrate 2 is shown in top view as follows: Figure 1The antenna 10 is formed by patterning a long side along a first direction and a short side along a second direction orthogonal to the first direction. The substrate 2 is a printed circuit board formed by alternating layers of conductors, such as copper foil, and insulating layers made of insulating material. In this embodiment, a double-layer substrate is used, for example. A double-layer substrate is a substrate formed by stacking two conductor layers via insulating layers. The surface layer of the substrate 2 refers to the conductor layer on one side of one face of the substrate 2, and its surface may also be provided with an insulating layer. Furthermore, the substrate 2 may be a four-layer substrate, a six-layer substrate, or a substrate with more layers.

[0021] like Figure 2 As shown, the first antenna 11 is constructed from a power supply line 11A formed by removing (etching) the conductors constituting the conductive layer. The first antenna 11 is powered from one end 11B and the other end 11C is open. One end 11B of the power supply line 11A is supplied with power from the control unit 40 via a wiring pattern 71. The other end 11C of the power supply line 11A is constructed such that the conductors surrounding it, excluding the power supply line 11A, are etched and separated from the surrounding conductors. Thus, in the power supply line 11A, current flows from one end 11B to the other end 11C, enabling the transmission and reception of polarized waves in a second direction orthogonal to the first direction.

[0022] like Figure 3 As shown, the second antenna 12 is composed of a power supply line 12A formed by etching a conductor that constitutes a conductive layer. The second antenna 12 is powered from one end 12B and the other end 12C is electrically connected to the ground region G. One end 12B of the power supply line 12A is supplied with power from the control unit 40 via a wiring pattern 72. The other end 12C of the power supply line 12A is configured such that the conductors surrounding it, excluding the power supply line 12A, are etched and separated from the surrounding conductors. Furthermore, this other end 12C is connected to the ground region G via a chip component mounted on the pad L10. This chip component can be, for example, a capacitor or a coil. Alternatively, a chip jumper can be used. When using a capacitor or a coil, the power supply line 12A is electromagnetically connected to the ground region G. When using a chip jumper, the power supply line 12A is connected via an ohmic contact. In either case, current flows from one end 12B to the other end 12C in the power supply line 12A, enabling the transmission and reception of polarized waves in the first direction. Furthermore, in Figure 1 The central grounding region G is shown in the substrate 2 with an aspect ratio of 3:1 centered on the antenna 10, but it is not limited to this; for example, it can also be about 3:2.

[0023] The first antenna 11 and the second antenna 12 are configured such that their antenna lengths are equal. Therefore, the first antenna 11 and the second antenna 12 are capable of receiving radio waves in the same frequency band.

[0024] The first antenna 11 and the second antenna 12 are formed in the central region of the substrate 2 along the first direction. The central region of the substrate 2 along the first direction refers to the region of the substrate 2 that is separated from both ends of the first direction, and is not limited to the center of the first direction. Therefore, the first antenna 11 and the second antenna 12 are formed in the central region of the substrate 2 that is separated from both ends of the first direction.

[0025] Here, as described above, the first antenna 11 is capable of transmitting and receiving polarized waves in the second direction, and the second antenna 12 is capable of transmitting and receiving polarized waves in the first direction on the substrate 2. In this way, the first antenna 11 and the second antenna 12 are configured to transmit and receive polarized waves of different polarizations.

[0026] In this embodiment, the antenna 10 is positioned at least 1 / 10 of the wavelength of the radio wave between the two ends of the grounding region G along the first direction. As described above, the antenna 10 is capable of transmitting and receiving radio waves in a specified frequency band, but in this embodiment, this frequency band is in the range of 2.4 GHz to 2.5 GHz. The wavelength of the radio waves in this frequency band is 12 cm to 12.5 cm, so 1 / 10 of the wavelength corresponds to 1.2 cm to 1.25 cm. Therefore, the antenna 10 is positioned at least 1.25 cm between the two ends of the grounding region G along the first direction. In other words, the antenna 10 is positioned at least 1.25 cm from the two ends of the grounding region G in the substrate 2 towards the center of the first direction.

[0027] The removal section 20 is provided in the entire lower layer area of ​​each of the first antenna 11 and the second antenna 12 in the substrate 2, and is formed by removing the conductor layer. In this embodiment, the substrate 2 is a double-layer substrate, and the first antenna 11 and the second antenna 12 are formed in the first layer, which is the surface layer of the substrate 2. The substrate 2 also has a conductor layer in the second layer, which is the inner layer on the side opposite to the first layer.

[0028] like Figures 2-3 As shown, in the first layer where the first antenna 11 and the second antenna 12 are formed, the conductor layer surrounding the first antenna 11 and the second antenna 12 is removed across a predetermined range R. Furthermore, in the top view of the substrate 2, the conductor layer in the second layer overlapping with the range R is also removed. Therefore, the removal portion 20 corresponds to the area in the top view of the substrate 2 where the conductor layer is removed across the range R. Moreover, "formed by removing the conductor layer" means formed by etching the conductor layer. Therefore, the removal portion 20 is in a state where no conductor layer exists.

[0029] In this embodiment, the removal portion 20 is formed as a rectangle when viewed from above. The removal portion 20 is configured such that at least a portion of its outer edge contacts the outer edge 2A of the substrate 2 along the first direction. At least a portion of the outer edge refers to at least one of the four sides constituting the rectangle. If the four sides are respectively designated as side 20A, side 20B, side 20C, and side 20D, then sides 20A, 20B, and 20C are in contact with the grounding region G, but side 20D coincides with the outer edge 2A. Therefore, as... Figures 2-3 As shown, edge 20D does not contact the grounding region G. Thus, in this embodiment, the removal portion 20 contacts the grounding region G in three of the four surrounding directions, and contacts the outer edge portion 2A in the remaining direction.

[0030] The first antenna 11 is powered from the side 20A of the removal section 20. In this embodiment, the first antenna 11 extends from the side 20A along the sides 20B and 20D toward the side 20C. The top end (the other end 11C) of the first antenna 11 is electrically open as described above.

[0031] The second antenna 12 is powered from the side 20A of the removal section 20. In this embodiment, the second antenna 12 extends from the side 20A along sides 20B and 20D toward the side 20C. The top end (the other end 12C) of the second antenna 12 is electromagnetically connected to the grounding region G as described above.

[0032] An impedance adjustment unit 30 is provided on the antenna 10, enabling adjustment of the impedance of the antenna 10. In this embodiment, the impedance is adjusted by a chip component mounted on the substrate 2. In this embodiment, two impedance adjustment units 30 are connected in series with respect to the power supply line 11A in the first antenna 11. Additionally, one is connected in series with respect to the wiring pattern 71, and another is connected across the ground region G. Instead of the series connection, the chip component connected in series with respect to the wiring pattern 71 has a pad pattern to allow it to be connected across the wiring pattern 71 and the ground region G.

[0033] On the other hand, two impedance adjustment units 30 are provided in series in the second antenna 12 relative to the power supply line 12A. Here, as described above, the top end (the other end 12C) of the second antenna 12 is electrically connected to the grounding region G, but the pad L10 at this top end can also be used as an impedance adjustment unit 30. In addition, one is provided across the grounding region G relative to the wiring pattern 72.

[0034] In this embodiment, the first antenna 11 has pads L1 and L2 on the power supply line 11A. Additionally, pads L3 and L4 are provided on the wiring pattern 71. The pad of pad L3 closest to pad L4 can mount a chip component between itself and pad L31 located in the ground region G. Since pad L4 spans both the wiring pattern 71 and the ground region G, it may not be required. Furthermore, pads L1, L2, and L3 may each be equipped with jumper components (e.g., 0Ω resistors).

[0035] As described above, when the component impedance is adjusted by setting pads L1, L2, L3, and L4, inductors (e.g., chip inductors) and capacitors (e.g., ceramic capacitors) can be mounted.

[0036] In this embodiment, the second antenna 12 has pads L5 and L10 on the power supply line 12A. Additionally, pad L6 is provided on the wiring pattern 72. Since pad L6 spans the wiring pattern 72 and the grounding area G, it may not be necessary to include it. Furthermore, pads L5 and L10 may each be equipped with jumper components (e.g., 0Ω resistors).

[0037] As described above, when components are set on pads L5, L6, and L10 to adjust the impedance, inductors (e.g., chip inductors) and capacitors (e.g., ceramic capacitors) can be mounted.

[0038] In this embodiment, the length of the substrate 2 along the second direction orthogonal to the first direction is configured to be 1 / 3 or less of the wavelength of the radio wave. The frequency band in this embodiment is 2.4 GHz to 2.5 GHz, so 1 / 3 of the wavelength corresponds to 4 cm. Therefore, the substrate 2 in this embodiment is configured to have a length of 4 cm or less along the second direction. Furthermore, the length of the substrate 2 along the second direction orthogonal to the first direction is preferably 1 / 4 or less of the wavelength of the radio wave (i.e., 3 cm or less).

[0039] The control unit 40 supplies power to the first antenna 11 and the second antenna 12, and performs prescribed signal processing on the signals transmitted from the first antenna 11 and the second antenna 12.

[0040] [Other Implementation Methods]

[0041] Next, other embodiments of antenna element 1 will be described.

[0042] In the above embodiment, two opposing outer edges 2A along the first direction, which are respectively provided as the first antenna 11 and the second antenna 12, on the substrate 2, have been described. However, as Figure 4As shown, the first antenna 11 and the second antenna 12 may also be disposed on one of the two opposing outer edges 2A along the first direction in the substrate 2.

[0043] In the above embodiments, examples of the first antenna 11 and the second antenna 12 being configured in a straight line shape have been described. However, at least one of the first antenna 11 and the second antenna 12 may also be configured in an L-shape. Furthermore, in the case of an L-shape configuration, the angle of the bend is not limited to 90 degrees; it may be less than 90 degrees or greater than 90 degrees.

[0044] In the above embodiment, the distance between the antenna 10 and the grounding region G along the first direction is described as being at least 1 / 10 of the wavelength of the radio wave. However, for example, the antenna 10 may also be provided at a location in the grounding region G along the first direction where the distance between the two ends is less than 1 / 10 of the wavelength of the radio wave.

[0045] In the above embodiment, a removal section 20 has been described, which is a substrate 2 having a removal section 20 disposed in the lower layer of each of the first antenna 11 and the second antenna 12, and in which the conductor layer has been removed. However, the substrate 2 may also be configured not to have a removal section 20.

[0046] In the above embodiment, the outer edge portion 2A of the conductor layer, which is provided as the removal portion 20, has been described. However, the removal portion 20 may also be configured to be separate from the outer edge portion 2A of the substrate 2.

[0047] In the above embodiment, the impedance adjustment section 30, which adjusts the impedance of the antenna 10, has been described. However, the antenna 10 may also be configured without the impedance adjustment section 30. In this case, for example, the inductive and capacitive components may be patterned.

[0048] In the above embodiment, the length of the substrate 2 along the second direction orthogonal to the first direction was described as less than 1 / 3 of the wavelength of the radio wave. However, the length of the substrate 2 along the second direction orthogonal to the first direction may also be longer than 1 / 3 of the wavelength of the radio wave.

[0049] In the above embodiment, the frequency band was described as a range of 2.4 GHz to 2.5 GHz. However, the frequency band may include frequencies lower than 2.4 GHz or frequencies higher than 2.5 GHz.

[0050] In the above embodiment, the pad L10, which serves as the other end 12C of the second antenna 12, is equipped with a jumper component. However, instead of the pad L10, the power supply line 12A can be electrically connected to the grounding area G by patterning.

[0051] [Summary of the above embodiments]

[0052] The following is a summary of the antenna element 1 described above.

[0053] (1) Antenna unit 1 is an antenna unit 1 having an antenna 10 capable of transmitting and receiving radio waves in a specified frequency band. The antenna 10 has a first antenna 11 and a second antenna 12. The first antenna 11 and the second antenna 12 are formed on a conductor layer of a substrate 2 extending in a first direction and are capable of transmitting and receiving waves with different polarizations. The first antenna 11 is powered from one end 11B and the other end 11C is open. The second antenna 12 is powered from one end 12B and the other end 12C is electrically connected to a ground region G. The first antenna 11 and the second antenna 12 are formed in a central region in the substrate 2 along the first direction.

[0054] According to this configuration, the first antenna 11 is formed in the central region of the substrate 2 along the first direction, powered from one end 11B and with the other end 11C open, thus enabling the transmission and reception of polarized waves orthogonal to the first direction. Furthermore, the second antenna 12 is formed in the central region of the substrate 2 along the first direction, powered from one end 12B and electrically connected to the ground region G at the other end 12C, thus enabling the transmission and reception of polarized waves in the first direction. Additionally, in this configuration, the length of the substrate 2 in the direction orthogonal to the first direction is not particularly limited, thus allowing for miniaturization of the substrate 2.

[0055] (2) In the antenna element 1 described in (1), the antenna 10 is configured to be spaced from the two ends of the grounding region G along the first direction by more than 1 / 10 of the wavelength of the radio wave.

[0056] According to this configuration, a grounding pattern (grounding potential) can be ensured for each of the first antenna 11 and the second antenna 12, thereby improving the antenna characteristics of the first antenna 11 and the second antenna 12.

[0057] (3) In the antenna unit 1 described in (1) or (2), preferably, the substrate 2 has a removal portion 20 in which the conductor layer is removed, the removal portion 20 is provided in the entire area of ​​the lower layer of the first antenna 11 and the second antenna 12 respectively, and the removal portion 20 is provided in the outer edge portion 2A of the substrate 2.

[0058] According to this configuration, by configuring the removal portion 20, electromagnetic bonding with the conductor layers of the first antenna 11 and the second antenna 12 can be prevented. Furthermore, since the removal portion 20 is provided at the outer edge portion 2A, at least a portion around the first antenna 11 and the second antenna 12 is free of conductor layers. Therefore, the first antenna 11 and the second antenna 12 can possess the desired performance.

[0059] (4) In the antenna unit 1 described in (1) or (2), preferably, the antenna 10 is provided with an impedance adjustment section 30, which adjusts the impedance.

[0060] According to this configuration, even if the dimensions of the first antenna 11 and the second antenna 12 are reduced, impedance matching of the first antenna 11 and the second antenna 12 can be achieved through the impedance adjustment unit 30. Therefore, even if the antenna element 1 is miniaturized, the expected characteristics can be maintained.

[0061] (5) In the antenna element 1 described in (1) or (2), it is preferable that the length of the substrate 2 along the second direction orthogonal to the first direction is less than 1 / 3 of the wavelength of the radio wave.

[0062] According to this configuration, the length of the substrate 2 along the second direction can be shortened, thus allowing the antenna element 1 to be assembled into an elongated housing, for example. This increases the degree of freedom in the arrangement of the antenna element 1.

[0063] (6) In the antenna element 1 described in (1) or (2), preferably, the frequency band is in the range of 2.4 GHz to 2.5 GHz.

[0064] According to this configuration, the antenna element 1 can be used for communication such as Bluetooth (registered trademark).

[0065] Industrial utilization potential

[0066] The technology involved in this invention can be used in antenna units that have antennas for transmitting and receiving radio waves at a specified frequency.

[0067] Explanation of reference numerals in the attached figures

[0068] 1: Antenna element, 2: Substrate, 2A: Outer edge, 10: Antenna, 11: First antenna, 11B: One end, 11C: The other end, 12: Second antenna, 12B: One end, 12C: The other end, 20: Removal part, 30: Impedance adjustment part, G: Grounding area.

Claims

1. An antenna element comprising an antenna capable of transmitting and receiving radio waves in a specified frequency band, wherein, The antenna has a first antenna and a second antenna, which are formed on a conductor layer of a substrate extending along a first direction and are capable of transmitting and receiving waves with different polarizations. The first antenna is powered from one end and open-circuited at the other end. The second antenna is powered from one end and electrically connected to a grounded area at the other end. The first antenna and the second antenna are formed in the central region of the substrate along the first direction.

2. The antenna element according to claim 1, wherein, The antenna is spaced from both ends of the grounding region along the first direction by more than 1 / 10 of the wavelength of the radio wave.

3. The antenna element according to claim 1 or 2, wherein, The substrate has a removal portion where the conductor layer is removed, and this removal portion is disposed over the entire area beneath each of the first antenna and the second antenna. The removal portion is disposed on the outer edge of the substrate.

4. The antenna element according to claim 1 or 2, wherein, The antenna is provided with an impedance adjustment section, which adjusts the impedance.

5. The antenna element according to claim 1 or 2, wherein, The length of the substrate along a second direction orthogonal to the first direction is less than 1 / 3 of the wavelength of the radio wave.

6. The antenna element according to claim 1 or 2, wherein, The frequency band is in the range of 2.4 GHz to 2.5 GHz.

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