JP2015146485A - Antenna device and wireless communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna device which facilitates installation of an antenna device and laying of a coaxial cable when building a wireless LAN system or the like by arranging a plurality of antennas, and makes distribution of high frequency signal power to each antenna device adjustable.SOLUTION: An antenna device includes: an antenna substrate (10); an antenna element (11) formed on the antenna substrate in planar pattern; a ground plate (G); a main coupling line (23) and a sub-coupling line (25) arranged closely on the antenna substrate and mutually coupling electromagnetically; and degree of coupling adjustment means (26-28) for adjusting the degree of electromagnetic coupling between both lines. The sub-coupling line includes: a directional coupler (20) connected with the feeding point of the antenna element, and having an input terminal (22) connected with one end side of the main coupling line, and an output terminal (24) connected with the other end side; and a protective cover (30) covering the antenna substrate, antenna element, and directional coupler, and exposing the input terminal and output terminal to the outside.

Description

  The present invention relates to an antenna device configured such that a plurality of antenna elements can be easily connected in cascade. The present invention also relates to a wireless communication system in which a plurality of antenna devices are connected in cascade.

  A wireless LAN system is known as a system for performing wireless communication between a wireless base station and a wireless terminal device indoors or on the premises. For example, in the system shown in FIG. 10 of Japanese Patent Application Laid-Open No. 2004-179756 (Patent Document 1), a plurality of wireless base stations to which LAN cables are connected are installed on the ceiling or the like. In the wireless communication system shown in FIG. 1 of the same document 1, a leaky coaxial cable is meandered on the indoor ceiling in order to eliminate the dead area in the indoor wireless LAN system. Moreover, the object detection apparatus described in Japanese Patent Application Laid-Open No. 2000-9851 (Patent Document 2) extends a trunk cable connected to a controller to an object detection area (parking lot), and further from the trunk cable to a plurality of individual areas. The branch cable branched from the main cable is extended to each (parking space). A detection antenna is connected to the end of each branch cable, and the presence or absence of an object (vehicle) in an individual area is detected by a reflected wave of the radio wave.

JP 2004-179756 A JP 2000-9851 A

  However, when building a wireless LAN system after the building is completed, a new antenna will be installed on the indoor ceiling, a leaky coaxial cable will be installed, a trunk cable will be laid, and the branch cable will be branched and wired to the antenna This is time consuming and expensive.

  In addition, when rooms are separated by fire walls to prevent the spread of fire, as in hotel rooms, it is necessary to make holes in the walls in order to pass coaxial cables inside and outside the rooms and between rooms. .

  In addition, when each room is lined up along the corridor like a hotel or apartment, it is conceivable to lay a leaky coaxial cable in the corridor and feed power from one access point, but as you move away from the feed point The high-frequency signal propagating through the leaky coaxial cable is attenuated, and the intensity of the radio wave radiated from the leaky coaxial cable is also reduced.

  Also, in the direction orthogonal to the leaky coaxial cable laid in the corridor, the reception electric field tends to drop sharply when the cable is separated from the cable, and therefore the connectivity of the wireless terminal to the network may be deteriorated in the room.

  It is difficult to set the reception electric field strength of the wireless terminal in each room to the same level, or to distribute the high-frequency signal power supplied from the access point as desired in each room.

  Therefore, in the present invention, when a wireless LAN system or the like is constructed by arranging a plurality of antennas, the antenna device and the coaxial cable can be easily laid, and the antenna device capable of adjusting the distribution of high-frequency signal power to each antenna device. The purpose is to provide. It is another object of the present invention to provide a wireless communication system that uses a plurality of such antenna devices.

  An antenna device according to one embodiment of the present invention that achieves the above object includes an antenna substrate, an antenna element that is formed in a planar pattern on the antenna substrate, and an electromagnetic wave that is disposed close to the antenna substrate and electromagnetically connected to each other. A main coupling line and a sub coupling line coupled to each other, and coupling degree adjusting means for adjusting an electromagnetic coupling degree between the two lines, wherein the sub coupling line is connected to a feeding point of the antenna element, A directional coupler having an input terminal connected to one end of the line and an output terminal connected to the other end, and covering the antenna substrate, the antenna element, and the directional coupler, and the input terminal and the output terminal And a protective cover that is exposed to the outside.

  Various antenna elements such as a planar antenna, a monopole antenna, a broadband monopole antenna, a two-frequency shared monopole antenna, and a two-frequency shared planar antenna can be used.

  With this configuration, an antenna element, a variable coupling degree directional coupler, and two connection terminals (plugs) for tandem connection are provided on the antenna substrate, assembled as a single antenna device, and covered with a protective cover. Is called. By connecting such antenna devices to each other by wiring (coaxial cable) and connection terminals, a wireless communication system in which a plurality of antenna devices are connected in cascade can be configured.

  Furthermore, in the present invention, a knob for adjusting the degree of electromagnetic coupling from the outside is provided on the protective cover. Thereby, the power distribution to the antenna element can be adjusted by the antenna device.

  The main line or the sub-line is formed on a sub-board that can move in contact with the antenna board, and the distance between the main line and the sub-line can be adjusted. Thereby, a directional coupler with a variable coupling degree can be formed on the antenna substrate.

  The adjustment of the separation distance is a feed screw mechanism. The degree of coupling of the directional coupler can be adjusted by the amount of rotation of the screw.

  A wireless communication system according to an embodiment of the present invention is a wireless communication system in which a plurality of antenna devices described above are connected, and each antenna device is arranged for each reception area of a plurality of reception areas. The power supply of the high-frequency signal that is connected to the column by connecting the output terminal of the antenna device and the input terminal of the other antenna device and is supplied to one end side of the antenna device column connected to the column to reach each antenna element Is determined individually by adjusting the degree of coupling of the directional coupler of each antenna device. Accordingly, it is possible to set the radio field intensity of the reception area with the antenna device of each reception area, which is good.

  Further, for example, the coupling degree of the directional coupler of each antenna device is adjusted so that the attenuation amount of the high-frequency signal in the signal path from one end side of the antenna device row to each antenna element becomes substantially equal. Thereby, it is possible to set the radio field intensity of each reception area substantially equal, which is good.

  According to the present invention, a plurality of antenna devices can be easily connected in cascade, and the radiated power distribution of each antenna device can be individually adjusted with the adjustment knob of each antenna device.

It is explanatory drawing explaining the external appearance of the antenna apparatus of this invention. It is explanatory drawing explaining the structural example of an antenna apparatus. It is explanatory drawing explaining the function of a directional coupler. It is a graph explaining the directional characteristic example (E surface) of the radio wave radiation of an antenna apparatus. It is a graph explaining the directional characteristic example (H surface) of the radio wave radiation of an antenna apparatus. It is explanatory drawing explaining the example of cascade connection of an antenna apparatus. It is explanatory drawing explaining the other Example (planar antenna) of this invention. It is explanatory drawing explaining the other Example (planar antenna) of this invention. It is explanatory drawing explaining the other Example (planar antenna) of this invention. It is explanatory drawing explaining the other Example (planar antenna) of this invention. It is explanatory drawing explaining the other Example (monopole antenna) of this invention. It is explanatory drawing explaining the other Example (2 frequency sharing monopole antenna) of this invention. It is explanatory drawing explaining the other Example (broadband monopole antenna) of this invention. It is explanatory drawing explaining the other Example (2 frequency sharing planar antenna) of this invention. It is explanatory drawing explaining the example of the ground-plate pattern of the antenna substrate back surface of the antenna apparatus of this invention. It is explanatory drawing explaining the other ground-plate pattern example of the antenna substrate back surface of the antenna apparatus of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, corresponding parts are denoted by the same reference numerals, and description of such parts may be omitted.

  In the embodiment of the present invention, an antenna element, a variable coupling degree directional coupler, and two connection terminals (plugs) for tandem connection are provided on an antenna substrate, assembled as one antenna device, and a protective cover Covered with. By arranging such antenna devices at appropriate locations and connecting the antenna devices to each other by wiring (coaxial cable), a wireless communication system in which a plurality of antenna devices are connected in cascade can be easily configured.

  The protective cover is provided with a knob for adjusting the degree of coupling of the directional coupler from the outside. Thereby, the power distribution to the antenna element can be adjusted by the antenna device, and the installation of the antenna system of the wireless communication system is facilitated.

  1 and 2 are explanatory diagrams for explaining one embodiment of the antenna device of the present invention. 1A is a front view showing the appearance of the antenna device 1 in a state where the coaxial cable 50 is connected, and FIG. 1B is a side view thereof. FIG. 2 is an explanatory diagram for explaining the configuration of the antenna device 1. FIG. 2A shows a state in which the protective cover 30 is removed from the antenna device 1 to expose the antenna substrate. FIG. 5B shows a state where a protective cover is put on. The protective cover is provided with a knob 32 for adjusting the coupling degree.

  In the example shown in FIG. 1, the antenna device 1 is entirely covered with a protective cover 30 such as plastic. A knob 32 for adjusting the degree of coupling of the built-in directional coupler 20 is provided on the lower right side of the front side of the protective cover 30. An input terminal 22a and an output terminal 24a are provided below the antenna device 1. A main transmission path (main coupling line) 23 of the directional coupler 20 is formed between the input terminal 22a and the output terminal 24a. One end of a coaxial cable 50 a is connected to the input terminal 22 a by a connector 42. For example, a high frequency signal is supplied from the access point AP to the other end of the coaxial cable 50a. One end of a coaxial cable 50b is connected to the input terminal 24a by a connector 44, and the other end is connected to an input terminal of a next-stage antenna device (not shown).

As shown in FIG. 2A, an antenna device 1 includes, for example, an antenna substrate 10 that is a printed board using a dielectric plate having a thickness of about 3 mm, and an antenna formed with a conductor pattern on the surface side of the antenna substrate 10. The element 11, the directional coupler 20 provided at the feeding point of the antenna element, and a later-described ground plane G formed on the back surface of the antenna substrate 10. In the illustrated example, the antenna element 11 is a planar antenna, but is not limited to a planar antenna as will be described later. The directional coupler 20 has a main transmission line 23 and a sub transmission line (sub-transmission lines) having a length of about ¼ wavelength to 1/20 wavelength (determined appropriately depending on the degree of coupling) of the electromagnetically coupled high-frequency signal. A coupling line) 25. The main transmission line 23 and the sub transmission line 25 are formed by, for example, a microstrip line, but are not limited thereto. One end of the main transmission line 23 is connected to the central conductor of the coaxial cable 50 a via the input terminal 22, and the other end is connected to the central conductor of the coaxial cable 50 b via the output terminal 24. The main transmission path 23 is formed on a movable substrate 21 configured to be movable relative to the antenna substrate 10, and is preferably relative to the sub transmission path 25 by a screw mechanism 26 formed of an insulator. Moving. The screw mechanism 26 is adapted to engage with the rotating shaft of the knob 32 when the protective cover is attached. One end side of the sub-transmission path 25 of the directional coupler 20 is connected to the feeding point of the antenna element 11, and the other end side is connected to the island 12, which is a ground potential, via a termination resistor (or adjustment resistor) 13. For example, the termination resistor 13 is set to about 50 to 100Ω depending on the degree of coupling.
As described above, the ground plate G of the planar antenna as shown by a two-dot chain line in FIG. 2A is formed on the back surface side of the antenna substrate 10. An example of the main plate is shown in FIG. In this example, the conductor pattern of the ground plane G is a so-called solid ground covering almost the entire back surface of the substrate, and is connected to the shield line (ground potential) of the coaxial cable 50a. Similarly, in the planar antenna shown in FIGS. 7 to 10 and FIG. 14 to be described later, a ground plane G is formed on the back side of the antenna substrate 10.

  In this configuration, when the knob 32 shown in FIG. 2B is rotated, the main transmission path 23 of the directional coupler 20 moves, and the electromagnetic coupling between the main transmission path 23 and the sub-transmission path 25 changes. As a result, the amount of high-frequency energy that branches (propagates) from the main transmission path 23 side to the sub-transmission path 25 side changes. The degree of coupling (coupling loss) with respect to the rotation angle of the knob 32 is measured in advance, and a scale of the degree of coupling with respect to the rotation angle of the knob 32 is displayed on the protective cover 32 around the knob 32. As a result, it can be used as a guide for adjusting the coupling level, and it is easy to install and adjust antennas and coaxial cables.

The directional coupler 20 is constituted by a sub-transmission path 25 having a length of ¼ wavelength or less of a high-frequency signal that is electromagnetically coupled to the main transmission path 23.
FIG. 3 is an explanatory diagram for explaining the degree of directional coupling in the directional coupler 20. The directional coupler 20 can be represented by a four-terminal circuit as shown in FIG. A main transmission path 23 is disposed between the terminals (1) and (2), and a sub transmission path 25 is disposed between the terminals (3) and (4). Since the terminal (4) is terminated by a resistor in the application of the present invention, the flow of the high-frequency signal will be described using the terminals (1) to (3).
As shown in FIG. 5B, main transmission high-frequency power is transmitted through the main transmission line 23 between the terminal (1) and the terminal (2), and the degree of coupling between the main transmission line 23 and the terminal (3) is increased. Corresponding high frequency power is input and output. The coupling from the terminal (1) to the terminal (3) is a forward coupling, and forward coupled radio frequency power is transmitted. The coupling from the terminal (2) to the terminal (3) is reverse coupling, and reverse coupled high frequency power is transmitted. Here, the forward coupling is coupled with the set coupling degree, and the reverse coupling degree is generally -20 dB (power ratio 1%) to -30 dB (power ratio 0.1%) of the forward junction. Direction can be given to (degree of coupling).
As shown in FIG. 6 to be described later, in this case, in the tandem connection of a plurality of antenna devices, for example, a signal received by each antenna device is directed only in the direction of the access point (AP) 2 (upstream side). 2 does not flow in the direction opposite to the antenna device direction (downstream side).

  FIG. 4 shows an example of directivity on the E (electric field) plane of the antenna device (planar antenna) 1. The frequency of the high frequency signal is 2450 MHz. As shown in the figure, a substantially single directivity characteristic is obtained on the E plane.

  FIG. 5 shows an example of directivity on the H (magnetic field) plane of the antenna device (planar antenna) 1. The frequency of the high frequency signal is 2450 MHz. As shown in the figure, a substantially single directivity characteristic is obtained on the H plane.

  FIG. 6 shows an example in which a plurality of antenna devices 1 described above are connected in cascade to form a wireless communication system. For example, as shown in FIG. 6A, the interior of the building 3 is divided into areas 0-4. For example, when the building 3 is a hotel or an apartment, each area corresponds to a room, a spare room, or the like. In area 0, an access point (AP) 2 is installed. In each area 1-4, antenna devices 1a to 1d that communicate with wireless terminals in the area are installed. Each area may include a corridor, and can communicate with wireless terminals in the area (room) from the antenna devices 1a to 1d installed in the corridor (the end of the area) by a directional antenna.

  The access point 2 is connected to a local area network (wired LAN) (not shown) and converts, for example, a network signal into a prescribed wireless LAN signal (2.4 GHz, 5 GHz). This high frequency signal is supplied to the input terminal 22a of the antenna device 1a in the area 1 through the coaxial cable 50a. Further, the output terminal 24a of the antenna device 1a in the area 1 and the input terminal 22a of the antenna device 1b in the area 2 are connected by the coaxial cable 50b, and a high-frequency signal from the access point 2 is supplied. Similarly, the output terminal 24a of the antenna device 1b in the area 2 and the input terminal 22a of the antenna device 1c in the area 3 are connected by the coaxial cable 50c, and a high frequency signal from the access point 2 is supplied. The output terminal 24a of the antenna device 1c in the area 3 and the input terminal 22a of the antenna device 1d in the area 4 are connected by the coaxial cable 50d, and a high frequency signal from the access point 2 is supplied. In this example, since the antenna device 1d in the area 4 is the end of the cascade connection, an antenna device that does not incorporate a directional coupler is used. When the antenna device 1n including a directional coupler is used at the end of the cascade connection, a termination resistor is connected to the output terminal of the antenna device 1n.

The series distribution of the high-frequency power in the multiple antenna connection of this embodiment does not cause a signal received by one antenna device to be re-radiated by another antenna device, cause crosstalk, or deteriorate communication quality.
For example, the flow of a high-frequency signal received by the antenna device 1b will be described. The high-frequency signal received by the antenna device 1b does not flow downstream by the directional coupler of the antenna device 1b, but goes only upstream. Although there is an antenna device 1a upstream, it does not flow to the high-frequency signal antenna device 1a received by the directional coupler of the antenna device 1a but goes to the access point 2. The high-frequency signal transmitted from the access point 2 is distributed to each antenna device at a preset distribution ratio, but the high-frequency signal received by each antenna device goes to only the access point 2 without flowing to other antenna devices. That is, isolation between each antenna device is achieved by incorporating a directional coupler in each antenna device. Since each antenna device is provided with an isolation function, there is an advantage that the installation and handling of a plurality of antenna devices is easy and the high-frequency power distribution ratio can be changed.

  FIG. 6B shows an example of signal loss in the power feeding system of the wireless communication system having the above configuration. In this example, the power of the high-frequency signal supplied to each antenna element is adjusted to be equal to −10.45 dBm by adjusting the coupling loss in the coupling degree variable directional couplers of the antenna devices 1a to 1c. .

  When 1 mW is set to 0 dBm, the loss of the 2 m coaxial cable 50a connecting the access point 2 and the antenna device 1a is -0.54 dB, and the coupling degree of the antenna device 1a is adjusted to -9.91 dB to the antenna element. Is adjusted to be 10.45 dBm.

  For the antenna device 1b, the loss of the coaxial cable 50a is -0.54 dB, the passage loss of the directional coupler of the antenna device 1a is -0.47 dB, and the loss of the coaxial cable 50b (length 8 m) is -2. Since it is 16 dB, the coupling degree of the antenna device 1 b is adjusted to −7.28 dB, and the power supplied to the antenna element is adjusted to be −10.45 dBm.

  For the antenna device 1c, the loss of the coaxial cable 50a is -0.54 dB, the passage loss of the directional coupler of the antenna device 1a is -0.47 dB, and the loss of the coaxial cable 50b (length 8 m) is -2. Since the transmission loss of the directional coupler of the antenna device 1b is −0.90 dB and the loss of the coaxial cable 50c (length 8 m) is −2.16 dB, the degree of coupling of the antenna device 1c is −4.22 dB. Adjustment is made so that the power supplied to the antenna element is -10.45 dBm.

  For the antenna device 1d, the loss of the coaxial cable 50a is -0.54 dB, the passage loss of the directional coupler of the antenna device 1a is -0.47 dB, and the loss of the coaxial cable 50b (length 8 m) is -2. 16 dB, the loss of the directional coupler of the antenna device 1b is -0.90 dB, the loss of the coaxial cable 50c (length 8 m) is -2.16 dB, and the loss of the directional coupler of the antenna device 1c is -2. Since the loss of 06 dB and the coaxial cable 50 c (length 8 m) is −2.16 dB, the feeding power to the antenna element is −10.45 dBm.

  In the example of FIG. 6B, the antenna device is adjusted so that the same high-frequency signal power is supplied to each antenna element. For example, the antenna device is arranged so that the high-frequency signal power is distributed according to the size of the area. The degree of coupling of the directional coupler may be adjusted.

  In this way, a plurality of antenna devices are connected in cascade, and the distribution ratio of the high frequency power to each antenna device can be set by adjusting the degree of coupling in the directional coupler in each antenna device. It turns out that laying and adjustment are easy.

  FIG. 7 is an explanatory diagram illustrating another configuration example of the antenna device. In the figure, parts corresponding to those in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 7A, in this example, the sub-transmission path 25 of the directional coupler 20 connected to the feeding point of the planar antenna 11 is arranged in the vertical direction as shown. The main transmission path 23 of the directional coupler 20 formed on the movable substrate 21 can move around the fulcrum 29, and the amount of movement of the movable substrate 21 by the feed screw mechanism 27 (the main transmission path 23 and the sub transmission path). 25 relative positions) is adjusted. Thereby, the electromagnetic coupling (coupling degree) between the main transmission path 23 and the sub transmission path 25 of the directional coupler 20 is adjusted. Further, as shown in FIG. 7B, the input terminal 22 a and the output terminal are provided on the front side of the protective cover 30.

  FIG. 8 is an explanatory diagram illustrating another configuration example of the antenna device. In the figure, parts corresponding to those in FIG. 7 are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 8A, in this example, the amount of movement of the movable substrate 21 (the relative position of the main transmission path 23 and the sub transmission path 25) is adjusted by the feed screw mechanism 28 having a bevel gear. As shown in FIG. 7B, the rotation of the adjustment knob 32 provided on the protective cover 30 is transmitted to the axis of the feed screw mechanism 28 orthogonal to the axis of the knob 32 by the bevel gear.

  FIG. 9 is an explanatory diagram illustrating another configuration example of the antenna device. In the figure, parts corresponding to those in FIG. 8 are denoted by the same reference numerals, and description thereof is omitted.

  In this example, as shown in FIG. 9A, the movable substrate 21 is linearly moved in the left-right direction along the guides 29a and 29b provided on the upper and lower sides of the movable substrate 21 by the feed screw mechanism 27. Like to do. Thereby, the electromagnetic coupling (coupling degree) between the main transmission path 23 and the sub transmission path 25 of the directional coupler 20 is adjusted.

  FIG. 10 is an explanatory diagram illustrating another configuration example of the antenna device. In the figure, parts corresponding to those in FIG. 8 are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 10A, in this example, the main transmission path 23 of the movable substrate 21 is overlapped with the sub transmission path 25. The amount of rotation around the fulcrum 29 of the movable substrate 21 is adjusted by the feed screw mechanism 28 having a bevel gear, and the cross positional relationship between the main transmission path 23 and the sub-transmission path 25 is set. The degree of coupling of the directional coupler 20 is determined corresponding to the positional relationship. As shown in FIG. 10B, the rotation of the adjustment knob 32 provided on the protective cover 30 is transmitted to the axis of the feed screw mechanism 28 orthogonal to the axis of the knob 32 by the bevel gear, and the rotation amount of the movable substrate 21 is reduced. Is set. The coupling degree of the directional coupler 20 is set according to the position of the knob 32.

  FIG. 11 is an explanatory diagram illustrating another configuration example of the antenna device. In the figure, parts corresponding to those in FIG. 8 are denoted by the same reference numerals, and description thereof is omitted.

As shown in FIG. 11A, in this example, a monopole antenna having a length corresponding to (1/4) wavelength of a high-frequency signal is used as the antenna element 11. A part of the microstrip line connected to the feeding point of the monopole antenna is used as the sub-transmission path 25. A ground plate G of a monopole antenna is formed on the back side of the antenna substrate 10. The main transmission path 23 of the movable substrate 21 is overlapped with the sub transmission path 25. The amount of rotation around the fulcrum 29 of the movable substrate 21 is adjusted by the feed screw mechanism 28 having a bevel gear, and the cross positional relationship between the main transmission path 23 and the sub-transmission path 25 is set. The degree of coupling of the directional coupler 20 is determined corresponding to the positional relationship. As shown in FIG. 11 (B), the rotation of the adjustment knob 32 provided on the protective cover 30 is transmitted to the screw shaft of the feed screw mechanism 28 orthogonal to the axis of the knob 32 by the bevel gear, and the rotation amount of the movable substrate 21. Is set. Thereby, the coupling degree of the directional coupler 20 is set according to the position of the knob 32.
As described above, the ground plane G of the monopole antenna as shown by a two-dot chain line in FIG. 11A is formed on the back surface side of the antenna substrate 10. An example of the base plate G is shown in FIG. In this example, the conductor pattern of the ground plane G is a so-called solid ground covering the lower half of the back surface of the substrate (not limited to this), and the position corresponding to the upper edge of the ground plane G is used as the antenna feeding point, and the ground plane G is not covered. A (1/4) wavelength monopole antenna extending on the antenna substrate toward the region (monopole antenna region) is formed. The ground plane G is connected to the shielded wire (ground potential) of the coaxial cable 50a. Also in the modified monopole antenna shown in FIGS. 12 to 13 described later, a ground plate G having the same shape is formed on the back side of the antenna substrate 10.

  FIG. 12 is an explanatory diagram illustrating another configuration example of the antenna device. In the figure, parts corresponding to those in FIG. 11 are denoted by the same reference numerals, and description thereof is omitted.

As shown in FIG. 12A, in this example, a dual-frequency monopole antenna is used as the antenna element 11. And lambda _1/4 main monopole antenna having a wavelength corresponding length of the antenna that resonates with the first frequency of the RF signal, the antenna length of the sub monopole antenna 11a of lambda _{2/4-wavelength} corresponding to the resonance in the second frequency of the high frequency signal Are connected at a feeding point in a V shape, and a directional coupler 20 is provided at the feeding point. The feeding point is connected to the sub transmission path 25, and the main transmission path 23 of the movable substrate 21 is overlapped with the sub transmission path 25. The amount of rotation around the fulcrum 29 of the movable substrate 21 is adjusted by the feed screw mechanism 28 having a bevel gear, and the cross positional relationship between the main transmission path 23 and the sub-transmission path 25 is set. The degree of coupling of the directional coupler 20 is determined corresponding to the positional relationship. As shown in FIG. 12B, the rotation of the adjustment knob 32 provided on the protective cover 30 is transmitted to the screw shaft of the feed screw mechanism 28 orthogonal to the axis of the knob 32 by the bevel gear, and the amount of rotation of the movable substrate 21. Is set. Thereby, the coupling degree of the directional coupler 20 is set according to the position of the knob 32.

  FIG. 13 is an explanatory diagram illustrating another configuration example of the antenna device. In the figure, parts corresponding to those in FIG. 11 are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 13A, in this example, a broadband monopole is used as the antenna element 11. The broadband monopole has a fan-shaped antenna pattern extending from the feed point. A directional coupler 20 is provided at this feeding point. The feeding point is connected to the sub transmission path 25, and the main transmission path 23 of the movable substrate 21 is overlapped with the sub transmission path 25. The amount of rotation around the fulcrum 29 of the movable substrate 21 is adjusted by the feed screw mechanism 28 having a bevel gear, and the cross positional relationship between the main transmission path 23 and the sub-transmission path 25 is set. The degree of coupling of the directional coupler 20 is determined corresponding to the positional relationship. As shown in FIG. 13B, the rotation of the adjustment knob 32 provided on the protective cover 30 is transmitted to the screw shaft of the feed screw mechanism 28 orthogonal to the axis of the knob 32 by the bevel gear, and the amount of rotation of the movable substrate 21. Is set. Thereby, the coupling degree of the directional coupler 20 is set according to the position of the knob 32.

  FIG. 14 is an explanatory diagram illustrating another configuration example of the antenna device. In the figure, parts corresponding to those in FIG. 10 are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 14A, in this example, the antenna element 11 is constituted by a two-frequency shared planar antenna. A directional coupler 20 is provided at the feeding point of the two-frequency shared planar antenna. The feeding point is connected to the sub transmission path 25, and the main transmission path 23 of the movable substrate 21 is overlapped with the sub transmission path 25. The amount of rotation around the fulcrum 29 of the movable substrate 21 is adjusted by the feed screw mechanism 28 having a bevel gear, and the cross positional relationship between the main transmission path 23 and the sub-transmission path 25 is set. The degree of coupling of the directional coupler 20 is determined corresponding to the positional relationship. As shown in FIG. 14 (B), the rotation of the adjustment knob 32 provided on the protective cover 30 is transmitted to the screw shaft of the feed screw mechanism 28 orthogonal to the axis of the knob 32 by the bevel gear, and the rotation amount of the movable substrate 21. Is set. Thereby, the coupling degree of the directional coupler 20 is set according to the position of the knob 32.

  As described above, the antenna device of the present embodiment has various antenna elements, a ground plane, a variable coupling degree directional coupler, an input terminal, an output terminal, and an adjustment knob on the antenna substrate. A plurality of antenna devices can be easily connected in tandem with a feeder line. In addition, power distribution in each antenna device can be easily set. Therefore, it is convenient to use in a wireless communication system using a plurality of antennas such as a private wireless LAN.

  In the embodiment of the present invention, each antenna device incorporates a directional coupler to achieve isolation between the antenna devices. Therefore, a plurality of antenna devices are connected in series and the power of the high-frequency signal is serially connected. Even if the signals are distributed, a high-frequency signal received by one antenna device is not re-radiated by another antenna device, crosstalk occurs, and communication quality is not deteriorated.

  In addition, since each antenna device incorporates a directional coupler with a variable coupling degree, the distribution ratio of high-frequency power to each antenna device can be easily changed. Therefore, installation and handling are easy.

  Note that the coupling degree variable mechanism in the directional coupler is not limited to the embodiment, and the coupling degree variable mechanism that adjusts the capacity between the main transmission path 23 and the sub transmission path 25 with a variable capacitance diode, the sub transmission path 25. A coupling degree variable mechanism configured to vary the resistance value using an FET as a connected resistor, and a coupling degree variable mechanism that mechanically adjusts a gap between the main transmission path 23 and the sub transmission path 25 are appropriately selected. Can do.

1 antenna device, 2 access point, 10 antenna substrate, 11 antenna element, 12 island (ground potential), 20 directional coupler, 21 movable substrate, 22 input terminal, 24 output terminal, 26, 27, 28 Movement of working substrate Mechanism, 30 Protective cover, 32 Adjustment knob, 50, 50a-50d Coaxial cable, G Ground plate

Claims (6)

An antenna substrate;
An antenna element formed in a planar pattern on the antenna substrate;
A main coupling line and a sub coupling line which are arranged close to each other on the antenna substrate and electromagnetically coupled to each other; and a degree of coupling adjustment means for adjusting the degree of electromagnetic coupling between the two lines. Is connected to a feeding point of the antenna element, an input terminal is connected to one end side of the main coupling line, and an output terminal is connected to the other end side; and
A protective cover that covers the antenna substrate, the antenna element, and the directional coupler, and that exposes the input terminal and the output terminal to the outside;
An antenna device comprising:   Furthermore, the antenna apparatus of Claim 1 with which the knob which adjusts the said electromagnetic coupling degree from the outside is provided in the said protective cover.   The main line or the sub-line is formed on a sub-board that is movable in contact with the antenna board, and the separation distance between the main line and the sub-line is adjustable. Antenna device.   The antenna device according to claim 3, wherein the adjustment of the separation distance is a feed screw mechanism. A wireless communication system in which a plurality of antenna devices according to any one of claims 1 to 4 are connected,
Each antenna device is arranged for each reception area of a plurality of reception areas, and connected in a column by connecting the output terminal of one antenna device and the input terminal of the other antenna device,
Wireless communication in which power distribution of high-frequency signals supplied to one end side of antenna device rows connected in series and reaching each antenna element is individually determined by adjusting the coupling degree of the directional coupler of each antenna device. system.   6. The radio according to claim 5, wherein the coupling degree of the directional coupler of each antenna device is adjusted such that the attenuation amount of the high-frequency signal in the signal path from one end side of the antenna device row to each antenna element is substantially equal. Communications system.

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