JP2007228413A - Antenna device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form optimum directivity at all times even if the height of an antenna changes, and to ensure a fixed communication area by one antenna. <P>SOLUTION: A supporting structure 17 is hung from a ceiling 16 in a television studio 11, and the antenna 31 for relay is mounted to the supporting structure 17 with a plurality of lighting systems 19. A lighting height control section 23 drives a support mechanism 22 by a vertical movement control signal to adjust the height of the lighting system 19. The antenna 31 comprises an antenna element 32 and a reflecting plate 33. The position of a reflecting plate 33 can be moved by the support mechanism 34. A reflecting plate control section 35 drives the support mechanism 34 by a control signal given to the lighting height control section 23 for control to adjust the position of the reflecting plate 33. When the position of the antenna 31 is moved vertically following the movement of the lighting system 19, the distance (d) between the antenna element 32 and the reflecting plate 33 varies within 0.5 λ<SB>0</SB>, and the directivity of the antenna 31 is changed to ensure the fixed communication area. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an antenna device for video transmission of a studio wireless camera, and more particularly to an antenna device for securing a certain communication area even when the height of the antenna changes.

  In a television station studio, video captured by a television camera is transmitted to a main device such as an editing device, for example, a host computer, via a cable connected to the camera. In this case, since a human who cuts the cable is necessary so as not to obstruct the movement of the cameraman, a wireless camera that wirelessly transmits a signal transmitted by the cable has attracted attention.

  FIG. 7 shows a system configuration in a case where a video taken by a wireless camera is wirelessly transmitted to a main apparatus in a television station studio. In FIG. 7, reference numeral 11 denotes a television studio, and a wireless camera 13 is arranged on the floor 12 thereof. The wireless camera 13 includes an antenna 14 for wireless communication, and is installed on a transport base 15 so that it can move on the floor 12.

  A support structure 17 is suspended from a ceiling 16 of the television studio 11 by a support 18. A large number of lighting devices 19 are attached to the support structure 17 by means of attachment brackets 21. Further, a support mechanism 22 that moves the support structure 17 in the vertical direction and an illumination height control unit 23 that drives and controls the support mechanism 22 are provided at the attachment portion between the support column 18 and the support structure 17. The control unit 23 moves the support structure 17 in the vertical direction in accordance with a control signal sent from the control device (not shown) through the signal line 24 to adjust the position (height) of the illumination device 19.

  An antenna 25 is attached to the support structure 17 by an antenna mounting bracket 26. The antenna 25 is for transmitting and receiving signals to and from the antenna 14 of the wireless camera 13 and is connected to a host computer via a feeder line (not shown). That is, the video imaged by the wireless camera 13 is wirelessly transmitted between the antennas 14 and 25 and further sent to the host computer via the feeder line.

  Further, as a known technique related to the present invention, a dielectric substrate having a spiral conductor pattern disposed on the surface thereof and a metal reflector disposed behind the dielectric substrate, the dielectric substrate and the dielectric substrate according to the wavelength of the operating frequency are provided. A planar spiral antenna with a drive reflector is known in which the position of the metal reflector is moved so that the distance from the metal reflector is a quarter wavelength or an odd multiple of a quarter wavelength (for example, patents). Reference 1).

In recent years, the effective dielectric constant (ε) and permeability (μ) for electromagnetic waves transmitted through the artificial medium are both negative, and as a result, the refractive index is also negative. A technique that enables beam scanning in an arbitrary direction within a range of −42 degrees to +34 degrees has been studied (for example, see Non-Patent Document 1).
Japanese Patent Laid-Open No. 11-122029 Nikkei Electronics January 2, 2006 issue, page 75 “Left-Handed Metamaterial”

  According to the video transmission system shown in FIG. 7, the video captured by the wireless camera 13 can be transmitted to the host computer wirelessly, and the conventionally required video transmission cable can be eliminated.

  However, the support structure 17 is moved up and down by a vertical movement control signal in order to adjust the brightness in the studio. Therefore, the radio communication antenna 25 moves up and down together with the illumination device 19. When the position of the antenna 25 moves up and down, the width of the communication area changes, and there is a problem that the communication state between the antenna 25 and the wireless camera 13 becomes unstable.

  In this case, the communication area between the antenna 25 and the wireless camera 13 is determined by the directivity width of the antenna 25. That is, when the height of the illumination device 19 is low, the angle at which the antenna 25 looks into the communication area in the direction of the floor surface 12 becomes wide, and thus wide directivity is required. On the other hand, when the height of the lighting device 19 is high, the prospective angle becomes narrow. When the antenna 25 having a wide directivity is used as it is, there is a possibility that the radio wave is unnecessarily spread and erroneous communication is caused.

  In order to solve such a problem, conventionally, a plurality of antennas having different directivities are previously attached to the support structure 17, and the antenna having the optimum directivity according to the height of the illumination device 19, that is, the height of the antenna. The method of switching to is generally used.

  By using the above antenna switching method, it is possible to ensure a certain communication area even when the height of the antenna changes.

  However, in the above method, it is necessary to install a plurality of antennas having optimum directivities according to the height, and the antenna installation is troublesome and the antennas must be switched according to the height. There was a problem that became complicated.

  The present invention has been made to solve the above-described problems. Even when the height changes, the optimal directivity can always be formed, and a certain communication area can be secured with one antenna. An object of the present invention is to provide an antenna device that can be used.

  According to a first aspect of the present invention, in the antenna device fixed to the lighting fixing support structure that moves up and down, the directivity is varied based on the vertical movement control signal and the vertical position information of the lighting fixing support structure.

  According to a second aspect of the present invention, in the antenna device according to the first aspect of the present invention, the antenna element includes a reflection plate that reflects radio waves and a reflection plate driving unit, and the reflection plate driving unit is driven and controlled by a control signal. The directivity is varied by varying the distance between the reflector and the reflector.

  According to a third aspect of the present invention, in the antenna device according to the first aspect of the present invention, the antenna element includes a reflection plate that reflects radio waves and a reflection plate driving unit, and the reflection plate driving unit is driven and controlled by a control signal. The directivity is varied by varying the angle of the reflecting plate with respect to.

  According to a fourth aspect of the present invention, there is provided an antenna apparatus fixed to an illumination fixing support structure that moves up and down, and includes a plurality of antenna elements and a distribution circuit, and the distribution ratio of the distribution circuit to the plurality of antenna elements is changed by a control signal. The characteristic is variable.

  ADVANTAGE OF THE INVENTION According to this invention, even when the height of an antenna changes with position adjustment of an illuminating device, optimal directivity can be formed and a fixed communication area can be ensured with one antenna.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 shows a system configuration in which an antenna apparatus according to a first embodiment of the present invention is installed in a studio of a television station, and video captured by a wireless camera is transmitted wirelessly to a host computer constituting a main apparatus such as an editing apparatus. An example is shown.

  As shown in FIG. 1, a wireless camera 13 is disposed on the floor 12 of the television studio 11. The wireless camera 13 includes an antenna 14 for wireless communication, and is installed on a transport base 15 so that it can move on the floor 12. As the antenna 14 of the wireless camera 13, for example, a turn style antenna or a circular microstrip patch antenna that operates in a 2.4 to 2.5 GHz band is used.

  A support structure 17 is suspended from a ceiling 16 of the television studio 11 by a support 18. A plurality of lighting devices 19 are attached to the support structure 17 by mounting brackets 21. Further, the support column 18 is provided with a support mechanism 22 that moves the support structure 17 in the vertical direction and an illumination height control unit 23 that drives and controls the support mechanism 22. The illumination height control unit 23 moves the support structure 17 in the vertical direction in accordance with the vertical movement control signal sent from the control device (not shown) through the signal line 24, so that the position (height) of the illumination device 19 is changed. adjust.

  A relay antenna 31 is attached to the support structure 17 by an antenna mounting bracket 30. The antenna 31 includes, for example, an antenna element 32 such as a patch antenna or a dipole and a plate-like reflecting plate 33, and a feeding point of the antenna element 32 is connected to a host computer via a feeding line (not shown). That is, the antenna 31 is a wireless LAN antenna that relays between the wireless camera 13 and the host computer. The antenna 31 receives a video signal transmitted from the wireless camera 13 via the antenna 14 and transmits it to the host computer. Signals are transmitted and received between the antenna 31 of the wireless LAN and the antenna 14 of the wireless camera 13 using radio waves of, for example, 2.4 to 2.5 GHz band and millimeter wave band.

The antenna 31 has an antenna element 32 attached to the lower end of the antenna mounting bracket 30 and a reflector 33 attached to the upper position of the antenna 31 while maintaining a predetermined distance d. In this case, the reflecting plate 33 is attached to the antenna mounting bracket 30 via the support mechanism 34. In addition, the support mechanism 34 is provided with a reflector control unit 35, and a vertical movement control signal provided from the control device to the illumination height controller 23 via the signal line 24 is also input to the reflector control unit 35. The The reflector control unit 35 drives the support mechanism 34 according to the vertical movement control signal, and moves the position of the reflector 33 in the vertical direction. That is, the support mechanism 34 and the reflection plate control unit 35 constitute a reflection plate drive unit. The reflection plate control unit 35 moves the antenna element 32 when the lighting device 19 is moved to a lower position by the vertical movement control signal. When the illuminating device 19 moves to a higher position so that the distance d between the reflector 33 and the reflector 33 becomes larger within 0.5λ ₀ (λ ₀ is the wavelength at the used frequency), the antenna element 32 and the reflector 33 distance d is driven controls the support mechanism 34 to be smaller in 0.5 [lambda ₀ within adjusts the position of the reflector 33.

  The antenna 31 has a wide directivity when the distance d between the antenna element 32 and the reflector 33 is increased, and a narrow directivity when the distance d between the antenna element 32 and the reflector 33 is decreased. It becomes sex. Accordingly, when the lighting device 19 moves to a low position, the expected angle of the communication area of the antenna 31 is increased. When the lighting device 19 moves to a higher position, the expected angle of the communication area of the antenna 31 is increased. The distance d between the antenna element 32 and the reflecting plate 33 is adjusted so that becomes smaller.

  When the position of the antenna 31 moves up and down together with the lighting device 19 as described above, by changing the distance d between the antenna element 32 and the reflector 33, the directivity of the antenna 31 is changed and a certain communication area is secured. It is configured to do.

FIG. 2 shows an example of vertical plane directivity when the distance d between the antenna element 32 and the reflection plate 33 is changed. 2, directivity indicated by the solid line a case of setting the distance d between the antenna elements 32 and the reflector 33 to 0.25 [lambda _0, the distance of the directional shown by the broken line b and the antenna element 32 and the reflector 33 d the shows a case set to 0.35λ _0. If the distance d between the antenna element 32 and the reflecting plate 33 is 0.5λ ₀ or more, it is emitted not only in the right direction (270 ° direction) but also in the lateral direction, causing irregular reflection in the room. , the distance d between the antenna elements 32 and the reflecting plate 33 is set within 0.5 [lambda ₀ as described above.

  As is clear from FIG. 2, when the distance d between the antenna element 32 and the reflecting plate 33 is reduced, the directivity is narrow, and when the distance d between the antenna element 32 and the reflecting plate 33 is increased. Wide directivity.

  In the television studio 11 shown in FIG. 1, a vertical movement control signal is given from the control device to the illumination height control unit 23 via the signal line 24, the support structure 17 is moved, and the illumination device 19 is moved in the vertical direction. In this case, the antenna 31 moves in the vertical direction together with the illumination device 19. When the reflector control unit 35 receives a control signal for moving the illumination device 19 downward, the position of the antenna 31 is lowered, so that the distance d between the antenna element 32 and the reflector 33 is increased within 0.5λ. As described above, the support mechanism 34 is driven to adjust the position of the reflector 33, and the directivity of the antenna 31 is widened to ensure a predetermined communication area.

  In addition, when the reflector control unit 35 receives a control signal for moving the lighting device 19 upward, the position of the antenna 31 is increased, and therefore the distance d between the antenna element 32 and the reflector 33 is within 0.5λ. The support mechanism 34 is driven so as to be small, the position of the reflector 33 is adjusted, and the directivity width of the antenna 31 is narrowed to secure a predetermined communication area.

  Therefore, even if the position of the antenna 31 moves in the vertical direction in accordance with the position adjustment of the lighting device 19, the directivity of the antenna 31 is changed to be constant by changing the distance d between the antenna element 32 and the reflection plate 33. The communication area can be secured, and the video imaged by the wireless camera 13 can always be transmitted to the host computer in a stable state.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 3 shows a configuration example of a main part when the antenna device according to the second embodiment of the present invention is installed in a studio of a television station.

  The antenna device according to the second embodiment uses a corner reflector type reflector 37 instead of the reflector 33 in the first embodiment as shown in FIG. 3, and the angle of the reflector 37 with respect to the antenna element 32. And the directivity of the antenna 31A is varied. Since other configurations are the same as those of the first embodiment, the same portions are denoted by the same reference numerals, and detailed description thereof is omitted.

The antenna 31A includes an antenna element 32 and a corner reflector type reflector 37. The reflection plate 37 is formed in a corner reflector type using, for example, two conductor plates 37a and 37b, and the angle α of the conductor plates 37a and 37b can be changed by the support mechanism 34a. The conductor plates 37a and 37b are set such that the distance from the top to the front end is, for example, about 1.4λ ₀ , and the distance d from the top to the antenna element 32 is about 0.4λ ₀ .

  The support mechanism 34a is driven and controlled by the reflector control unit 35a. The reflector control unit 35a drives the support mechanism 34a by a vertical movement control signal given from the control device, and when a control signal for driving the lighting device 19 in the lower direction is given, the angle α of the conductor plates 37a, 37b. That is, the angle α of the reflecting plate 37 is increased and the directivity width of the antenna 31A is increased to ensure a predetermined communication area. In addition, when a control signal for driving the illumination device 19 in the lower direction is given, the reflector control unit 35a reduces the angle α of the reflector 37 and reduces the directivity of the antenna 31A to a predetermined value. Secure a communication area. The angle α of the reflection plate 37 is adjusted according to the position of the lighting device 19 with 90 ° as a reference, for example.

  According to the second embodiment, even if the position of the antenna 31A moves in the vertical direction in accordance with the position adjustment of the lighting device 19, the angle α of the reflecting plate 37 can be varied according to the height of the antenna 31A. By changing the directivity of the antenna 31A, a certain communication area can be secured, and the video imaged by the wireless camera 13 can be always transmitted to the host computer in a stable state.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG.
FIG. 4 shows a configuration example of a main part when the antenna device according to the third embodiment of the present invention is installed in a studio of a television station.

  As shown in FIG. 4, the antenna device according to the third embodiment uses a distribution circuit 40 instead of the reflector 33 in the first embodiment, and includes an antenna composed of a plurality of antenna elements 32a, 32b,. The directivity is variably set so as to secure a constant communication area by distributing power to 31B and changing the distribution ratio of the distribution circuit 40 in accordance with the height of the lighting device 19. Since other configurations are the same as those of the first embodiment, the same portions are denoted by the same reference numerals, and detailed description thereof is omitted.

  A vertical movement control signal given from the control device to the illumination height control unit 23 is input to the distribution circuit 40, and distribution ratios of the antenna elements 32a, 32b,..., 32n according to the height of the illumination device 19 are input. For example, as shown in FIG. FIG. 5 shows a configuration example of the distribution circuit 40 in the case where the power supply signal is distributed into four.

  In FIG. 5, reference numeral 41 denotes a control signal input terminal to which a vertical movement control signal is input from a control device, and a control unit 42 that variably controls the distribution ratio is connected to the input terminal 41. Reference numeral 43 denotes a power supply terminal connected to the host computer via a power supply line. A power supply signal supplied to the power supply terminal 43 is divided into two and input to attenuators (ATT) 44a and 44b. The output signals of the attenuators 44a and 44b are each divided into two and input to the attenuators 45a to 45d. The output signals of the attenuators 45a and 45b are output to the distribution terminals 47a and 47b via the phase shifters 46a and 46b, respectively. The output signals of the attenuators 45c and 45d are output to the distribution terminals 47c and 47d via the phase shifters 46c and 46d, respectively. Antenna elements 32a to 32d in FIG. 4 are connected to the distribution terminals 47a to 47d, respectively.

  The control unit 42 controls the attenuation amount of each attenuator 44a, 44b, 45a to 45d and the phase shift amount of the phase shifters 46a to 46d based on the vertical movement control signal given from the control device, and the antenna elements 32a to 32d. The distribution ratio with respect to is variable.

  When the control unit 42 is given a control signal for driving the lighting device 19 in a lower direction, the control unit 42 reduces the number of distribution of the antenna elements 32a, 32b,. A predetermined communication area is secured by widening the width of the directivity of 31B. Further, when a control signal for driving the lighting device 19 in the high direction is given, the control unit 42 increases the number of antenna elements 32a, 32b,..., That is, increases the number of antenna elements to be fed. Then, the width of the directivity of the antenna 31B is narrowed to secure a predetermined communication area.

  According to the third embodiment, even if the position of the antenna 31B moves in the vertical direction as the position of the lighting device 19 is adjusted, the distribution ratio of the distribution circuit 40 is varied according to the height of the antenna 31B. By changing the directivity of the antenna 31B, a certain communication area can be secured, and the video imaged by the wireless camera 13 can always be transmitted to the host computer in a stable state.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG.
FIG. 6 shows a system configuration example when the antenna device according to the fourth embodiment of the present invention is installed in a studio of a television station.

  In the first embodiment, the vertical movement control signal given to the illumination height control unit 23 is input to the reflector control unit 35 and the like to control the directivity of the antenna. As shown in FIG. 6, a height detector 51 is provided on the support structure 17 to detect the height of the support structure 17, and the detection signal is input to the reflector control unit 35 to control the directivity of the antenna. It is configured. Since other configurations are the same as those of the first embodiment, the same portions are denoted by the same reference numerals, and detailed description thereof is omitted.

  The height detector 51 detects the height from the floor surface 12 to the support structure 17 by response to radio waves such as an ultrasonic sensor, an infrared sensor, or a GPS or a wireless tag, and image processing. Input to the reflector control unit 35. The reflector control unit 35 varies the distance d between the antenna element 32 and the reflector 33 based on the signal detected by the height detector 51, and changes the directivity of the antenna 31 as described in the first embodiment. Set to the optimum value.

  According to the fourth embodiment, even if the position of the antenna 31 moves in the vertical direction in accordance with the position adjustment of the lighting device 19, the vertical movement control signal input to the lighting height control unit 23 is not used. The optimum directivity according to the height of the antenna element 32 can be realized.

  In the fourth embodiment, the case where the height detector 51 is mounted on the support structure 17 has been described. However, the height detector 51 is located at a place other than the support structure 17, such as the antenna mounting bracket 26 and the reflector 33. It is also possible to detect the height of the mounting part.

  In the fourth embodiment, the case where the directivity is set to the optimum value by changing the distance d between the antenna 31 and the reflector 33 by the height signal detected by the height detector 51 has been described. As shown in the second embodiment, the directivity is set to the optimum value by changing the angle α of the reflector 37, or the directivity is optimized by changing the distribution ratio of the distribution circuit 40 as shown in the third embodiment. Even when the value is set, the height signal detected by the height detector 51 can be input to the reflector control unit 35a or the distribution circuit 40 to set the directivity to the optimum value.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements without departing from the scope of the invention in the implementation stage.

It is a figure which shows the system structural example at the time of installing the antenna apparatus which concerns on 1st Embodiment of this invention in the studio of a television station. In the same embodiment, it is a figure which shows the vertical surface directivity at the time of changing the distance d of an antenna element and a reflecting plate. It is a figure which shows the structural example of the principal part at the time of installing the antenna apparatus which concerns on 2nd Embodiment of this invention in the studio of a television station. It is a figure which shows the structural example of the principal part at the time of installing the antenna apparatus which concerns on 3rd Embodiment of this invention in the studio of a television station. It is a figure which shows the structural example of the distribution circuit in the same embodiment. It is a figure which shows the system structural example at the time of installing the antenna apparatus which concerns on 4th Embodiment of this invention in the studio of a television station. It is a figure which shows the system structural example at the time of installing the conventional antenna apparatus in the studio of a television station.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Television studio, 12 ... Floor surface, 13 ... Wireless camera, 14 ... Wireless camera antenna, 15 ... Conveyance base, 16 ... Ceiling, 17 ... Support structure, 18 ... Post, 19 ... Illumination device, 21 ... Mounting bracket , 22 ... support mechanism, 23 ... control unit, 24 ... signal line, 30 ... antenna mounting bracket, 31, 31A, 31B ... wireless LAN antenna, 32, 32a to 32n ... antenna element, 33, 37 ... reflector, 34 , 34a ... support mechanism, 35, 35a ... reflector control unit, 37 ... reflector, 37a. 37b ... Conductor plate, 40 ... Distribution circuit, 41 ... Input terminal, 42 ... Control unit, 43 ... Feeding terminal, 44a, 44b, 45a-45d ... Attenuator, 46a-46d ... Phase shifter, 47a-47d ... Distribution terminal, 51. Detector.

Claims (4)

  An antenna apparatus that is fixed to an illumination fixing support structure that moves up and down, and that changes directivity based on an up / down movement control signal and vertical position information of the illumination fixing support structure.   The antenna device according to claim 1, further comprising an antenna element, a reflector that reflects radio waves, and a reflector driving unit, wherein the reflector driving unit is driven and controlled by a control signal, and the distance between the antenna element and the reflector is determined. An antenna device characterized in that the directivity is varied.   The antenna device according to claim 1, further comprising an antenna element, a reflector that reflects radio waves, and a reflector driving unit, wherein the reflector driving unit is driven and controlled by a control signal, and the angle of the reflector with respect to the antenna element is variable. An antenna device characterized by varying directivity.   An antenna device fixed to an illumination fixing support structure that moves up and down, comprising a plurality of antenna elements and a distribution circuit, and varying a distribution ratio of the distribution circuit to the plurality of antenna elements by a control signal to vary directivity. A feature antenna device.

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