JPH06232620A - Antenna system - Google Patents

Abstract

PURPOSE:To revise an elevating angle to maximize the sensitivity of an antenna in response to a moving location when a mobile body is moved. CONSTITUTION:The antenna system using a conductor wire 2 formed in spiral as a radiation element is provided with a cylindrical support 1 supporting the spiral conductor wire 2, a hollow cylindrical radome 3 fitted to the main body and covering the support 2 and a driver moving the support 1 vertically, one end of the conductor wire 2 is fixed in the vicinity of a lower end of the radome 3, the other end is fixed in the vicinity of an upper end of the support 1 and the driver moves the support 1 vertically to change a pitch of the spiral conductor wire 2. Since a major radiation direction of a beam over a wide area is easily set by one antenna, the replacement of plural antennas whose elevating angle is set specifically to the area depending on a moving destination is avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is used in a wireless communication device. INDUSTRIAL APPLICABILITY The present invention is suitable for use in a mobile station device for wireless communication relayed by a satellite. The present invention relates to an apparatus capable of performing satellite tracking by variably setting the direction of a cone beam by using a spiral conductor wire as a radiating element and making the spiral shape movable along a central axis.

[0002]

2. Description of the Related Art An antenna device using a spiral conductor wire as a radiation element as shown in FIG. 5 (a) or 5 (b) is known. This is also called a helical antenna and is called "Shaped
-con-ical radiation pattern performance of the bac
kfire quadrifilar helix ”(IEEE Trans.on Antennas &
Prop.vol.23,5,1975), "Radiation directivity of a two-wire wound helical antenna having a conical beam" (1991 IEICE Spring National Convention B-43).

It is known that this device, when used by being attached to a moving body such as an automobile so that its axial direction is vertical, exhibits a conical beam-shaped radiation characteristic around the vertical axis as shown in FIG. There is. Therefore, such an antenna device is used for a mobile station device of a mobile communication system using a relay satellite. That is, if the elevation angle that maximizes the sensitivity of the directional cone beam is set to be equal to the elevation angle of the relay satellite, no matter which direction the vehicle is facing, the vehicle stops or runs on level ground. As long as you can, you can always communicate with the relay satellite with maximum sensitivity.

FIG. 7 shows an example of the shape of such a conventional helical antenna. FIGS. 8 (a), 8 (b) and 8 (c) show when the pitch P of the helical antenna shown in FIG. 7 is changed. It shows the change in the directivity of. It can be seen that changing the pitch P significantly changes the directivity.

[0005]

However, when the mobile body stays in a specific area, the elevation angle with respect to the relay satellite changes when the mobile body moves far. The conventional antenna device as shown in FIG.
The elevation angle that maximizes its sensitivity is fixed and cannot be changed. Therefore, even if such an antenna device uses the same relay satellite, it is necessary to design an antenna device having optimum characteristics for each major city. It is often necessary to prepare a plurality of antenna devices having different characteristics for a mobile object that travels a long distance, and replace and use these antenna devices as the mobile device moves.

The present invention has been made against such a background, and it is an object of the present invention to provide an antenna device capable of changing the elevation angle, which is the maximum sensitivity, with movement. That is, the present invention is carried out by focusing on the fact that the antenna device having a spiral radiating element can change the elevation angle, which is the maximum sensitivity of directivity, by changing the diameter of the spiral and the pitch of the spiral. It is a thing.

[0007]

According to the present invention, in an antenna device having a spirally formed conductor wire as a radiating element, one end of the conductor wire is fixed to the main body of the device and the other end is a central axis of the spiral. It is characterized in that it is attached to a support body that moves along. It is desirable to provide a fixture that is attached to the vehicle body so that the central axis is in the vertical direction.

[0008]

Function: One end of the spirally formed conductor wire is fixed to the main body of the apparatus, and the other end is attached to a support body which moves along the central axis of the spiral, and this support body is moved to make a pitch between the conductor wires. And the main radiation direction of the beam is set to a desired elevation angle direction.

As a result, even if the satellite moves between areas having different satellite elevation angles, the antenna directivity can be set to the elevation angle that provides the maximum sensitivity according to the location of the movement, and high gain can be obtained.

Further, the device of the present invention is attached to the vehicle body by using the attachment, and the central axis is adjusted so as to be vertical. This makes it possible to set the directional characteristics to include the relay satellite regardless of whether the vehicle body faces north, south, east, or west.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an antenna device according to an embodiment of the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a view showing the arrangement of the essential portions of the first embodiment of the present invention.

In the first embodiment of the present invention, a cylindrical support 1 arranged in the vertical direction and a flexible conductor wire 2 spirally wound around the outer periphery of the support 1 with the same diameter. And a hollow cylindrical radome 3 that covers the outside thereof, a drive device 5 that moves the support 1 up and down via a connecting rod 4, and a power supply circuit 6 that supplies power to the conductor wire 2.

The support 1 is supported by the radome 3 via a support member 7 which is vertically slidable, one end of the conductor wire 2 is fixed near the lower end of the radome 3, and the other end is supported by the support 1. Is fixed near the upper end of the. The spiral conductor wire 2 expands and contracts in the longitudinal direction as the support 1 moves up and down.

The drive device 5 may have any structure capable of moving the support 1 up and down. For example, a hydraulic mechanism for directly connecting the connecting rod 4 to a cylinder to supply pressure oil and moving it up and down, or a connecting rod. It is possible to use a mechanical mechanism in which a rack is formed in a part of 4 and meshes with a gear, a handle is provided to rotate the gear manually, or an electric motor is provided to drive the gear.

The antenna device constructed as described above is fixed to the vehicle body (moving body) by the fixture 10. The fixture 10 shown in FIG. 1 includes a fixing member 11 on which the antenna device is placed and fixed, and a spherical body 12 connected to the fixing member 11.
And holding members 13 and 14 for holding the spherical body 12 by sandwiching it, and a fixing bolt 15 for fixing the spherical body 12.

The direction of the antenna device is set by the fixing bolt 1
This can be easily performed by loosening 5 and orienting the spherical body 12 in a desired direction and tightening the spherical body 12 again with the fixing bolt 15. By using this fixture 10, the center of the support can be set in the vertical direction regardless of the position of the vehicle body. It should be noted that the present invention can be implemented using a mounting tool having a configuration other than this.

When the support 5 is moved up or down by the drive unit 5 via the connecting rod 4, the lower end of the conductor wire 2 is fixed to the radome 3, and the upper end thereof is fixed to the support 1. Since it is fixed, the upper end of the conductor wire 2 moves as the support 1 moves, and the spiral conductor wire 2 is elongated or compressed in the longitudinal direction. When expanded, the pitch becomes large, and when compressed, the pitch becomes small.

FIG. 2 shows the measured values in the main radiation direction of the beam when the pitch is changed in this way, and the horizontal axis represents the pitch normalized by wavelength (P / λ, P: pitch,
λ: wavelength), and the vertical axis represents the angle (deg) in the main radiation direction
Indicates. As can be seen from this measurement result, by changing the pitch, the main radiation direction of the beam can be changed while maintaining the characteristics of the cone beam. In this measurement example, the main radiation direction was around 35 (deg) when the pitch was 0.45 (P / λ), but when the pitch was increased to 0.65 (P / λ), Radial direction is 75 (d
eg) has changed to the vicinity. This means that it can be covered almost even if it moves in the temperate zone on the ground.

As a result, the main radiation direction of the beam can be reduced to zero by an operation of moving the support 1 with one antenna device.
It can be easily set to any position within the range of to 75 (deg).

In the frequency band of 1 to 2 GHz assigned to mobile communication by satellite relay, the radome length is 20.
It becomes about 30 cm, and the number of turns of the conductor wire 2 becomes about 5 turns. A device that can obtain position information such as GPS (Global Positioning System) or Loran is provided for the control for moving the support 1 up and down, and the satellite elevation angle is obtained from the information, and the support 1 is moved up and down. It is also possible to move the pitch of the spiral conductor wire 2 to an appropriate value and set the main radiation direction of the cone beam to the optimum direction. Tracking can be performed.

(Second Embodiment) FIG. 3 is a view showing the arrangement of the essential parts of a second embodiment of the present invention.

In the second embodiment of the present invention, the radome 3 has a hermetically sealed structure, and the inside of the radome 3 is filled with an insulative semi-solid state (grease-like) dielectric material 8 having a small electrical loss, and the power feeding circuit 6 is provided inside. It is configured to be installed and connected to the communication device by the power supply line 9.

In the case of the second embodiment of the present invention as described above, when the drive device 5 moves the support 1 up and down through the connecting rod 4, the resistance increases, but when it is set at a predetermined position. Since the conductor wire 2 is held by the semi-solid dielectric 8 at a uniform pressure, it is possible to suppress mechanical vibration, eliminate minute deviations in the radial direction due to vibration, and accurately set the elevation angle. .

(Third Embodiment) FIG. 4 is a view showing the arrangement of the essential parts of a third embodiment of the present invention.

In the third embodiment of the present invention, a metal conductor having elasticity is used for the conductor wire 2, a support head 1a having a diameter larger than the diameter is provided on the upper end of the support 1, and the conductor wire 2 is It is sandwiched between the support head 1a and the support member 7 in a non-fixed state.

In the case of the third embodiment, since the conductor wire 2 has elasticity when the support 1 is moved up and down by the drive device 5, the conductor wire 2 receives an external force due to its spring action. Instead, the pitch is increased or decreased, and the pitches between the spirals are made uniform, so that the directional characteristics can be made highly accurate.

[0028]

As described above, according to the present invention, when the moving body moves, the elevation angle can be easily changed so that the sensitivity of the antenna becomes maximum according to the moving place. , It is possible to eliminate the need to change multiple antennas that set the elevation direction unique to each area at the destination each time, and it is possible to easily and arbitrarily set the main radiation direction of the beam over a wide area with one antenna device. effective.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a main part of a first embodiment of the present invention.

FIG. 2 is a diagram showing measured values in the main radiation direction when the pitch is changed by the device of the first embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a main part of a second embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a main part of a third embodiment of the present invention.

5A and 5B are diagrams showing a configuration of an antenna according to a conventional technique.

FIG. 6 is a diagram for explaining the conical beam radiation directivity of a helical antenna.

FIG. 7 is a diagram showing an example of the shape of a helical antenna.

8A, 8B, and 8C are diagrams showing directivity when the pitch of the helical antenna shown in FIG. 7 is changed.

[Explanation of symbols]

 1 Support 1a Support Head 2 Conductor Wire 3 Radome 4 Connecting Rod 5 Driving Device 6 Feeding Circuit 7 Supporting Member 8 Dielectric 9 Feeding Wire 10 Fixture 11 Fixing Member 12 Spherical Body 13, 14 Holding Member 15 Fixing Bolt

Claims (2)

[Claims] 1. An antenna device using a spirally formed conductor wire as a radiation element, wherein one end of the conductor wire is fixed to the main body of the device and the other end is a support body that moves along the central axis of the spiral. An antenna device characterized by being attached. 2. The antenna device according to claim 1, further comprising a mounting tool that is mounted on the vehicle body so that the central axis is in a vertical direction.