JPH0662614U - Car antenna - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an in-vehicle antenna that is thin and can be installed in a narrow installation space, but is not easily affected by wind pressure and can achieve high efficiency even when the beam tilt angle is large. To do. An antenna element in which an antenna plate 12 which rotates in a plane substantially parallel to a horizontal plane via a rotation drive control means 13 is mounted on a vehicle body substantially horizontally via a shaft 11 and is inclined at a predetermined angle. 14 is provided on the antenna plate 12.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vehicle-mounted antenna, and more particularly to a vehicle-mounted antenna for receiving satellite broadcasting.

[0002]

[Prior art]

 In recent years, an increasing number of ordinary households have installed satellite broadcasting receiving antennas such as parabolic antennas and flat antennas indoors and outdoors to receive satellite broadcasting.

A large gain (about 30 dB) is required for receiving the satellite broadcasting receiving antenna, and the half-power width becomes narrower when trying to obtain the gain. Therefore, in the satellite broadcasting, a predetermined angle in the satellite direction from the vertical direction is obtained. (For example, in Tokyo, the tilt angle is about 50 degrees.) Only the antenna body is directed to receive.

Therefore, when a satellite broadcast receiving antenna for receiving satellite broadcasts is mounted on a moving body (for example, a vehicle), it is necessary to track the direction of the antenna main body in the direction of the satellite according to the movement of the vehicle. . As a method for tracking such an antenna body, phase monopulse control, step track control, gyro sensor, etc. are used. Further, in this case, the tracking range needs to be rotated by 360 degrees in the azimuth direction.

As such a conventional vehicle-mounted antenna, as shown in FIG. 4, an antenna main body 2 having an antenna element 1 is provided on a support base 3 in a state of being inclined at a predetermined angle. There is a system in which the rotation drive control means 4 controlled by the above-described control method is driven so as to follow the movement of the vehicle.

[0006]

[Problems to be solved by the device]

 By the way, in the vehicle-mounted antenna configured as described above, the antenna body 2 itself is formed thin, but since the antenna body 2 needs to be tilted, a predetermined height and azimuth angle of 360 degrees are secured. It is necessary to secure a rotation space for the antenna body 2 for this purpose.

Therefore, there is a problem that the vehicle body is narrow, the height is limited, and further, it is not suitable for the condition of receiving the wind pressure.

Therefore, there is a beam tilt realized by controlling the composite phase of the antenna element 1. However, when the beam tilt angle is a small value of 0 to 30 degrees, the efficiency drop is small, but If it exceeds 30 degrees, the efficiency will be significantly reduced. Therefore, a tilt angle of about 30 degrees is a practical limit, and the antenna body 2 must be tilted around 20 degrees in order to receive even with such an antenna, and the above-mentioned problems are completely solved. I couldn't.

In view of the above situation, the present invention is a vehicle that is thin and can be mounted in a small installation space, is not easily affected by wind pressure, and can achieve high efficiency even if the beam tilt angle is large. It is intended to provide an antenna.

[0010]

[Means for Solving the Problems]

 In order to achieve the object, the present invention provides an antenna plate mounted on a vehicle body substantially horizontally via an axis and rotating in a plane substantially parallel to a horizontal plane via a rotation drive control means, and an antenna plate at a predetermined angle. The gist of the present invention is that it is provided with an antenna element that is arranged so as to be inclined.

[0011]

[Action]

 In such a configuration, the antenna plate that rotates in a plane substantially parallel to the horizontal plane via the rotation drive control means is mounted on the vehicle body substantially horizontally via the shaft and is arranged at a predetermined angle. Elements are provided on the antenna plate.

With this, when the rotation drive control unit rotates the antenna plate about the axis according to the movement of the vehicle body, the antenna element maintains the state of being oriented in the satellite direction.

[0013]

【Example】

 Next, an embodiment of the vehicle-mounted antenna of the present invention will be described with reference to FIGS.

In FIG. 1, a vehicle-mounted antenna 10 includes a shaft 11 having a base end fixed to a vehicle body (not shown), and an antenna plate 12 as a radiation waveguide mounted on the tip of the shaft 11 so as to be relatively rotatable. A rotation drive control means 13 for detecting a movement of the vehicle body and rotating a gear 13a meshing with a gear portion 12a provided on a peripheral end surface of the antenna plate 12 to rotate the antenna plate 12 while maintaining the horizontal state; The plate 12 includes a large number of antenna elements 14 protruding from the upper surface.

As the antenna element 14 used here, for example, the helical element shown in FIG. 2 (A), the curl element shown in FIG. 2 (B), or the same antenna element piece as the conventional one is used as the shaft 14a. It is a three-dimensional antenna such as one that is tilted. As a result, the degree of freedom in designing the antenna gain, directional characteristics, etc. can be increased.

Further, as shown in FIG. 1B, the antenna element 14 is tilted at an angle θ from the axis of the shaft 11, and the directional characteristic of one antenna element 14 has the maximum gain in the direction of the spiral axis. Thus, the combined phase of each antenna element 14 is set so that the maximum gain direction and the setting direction of the beam tilt angle θ0 by the array are the same (θ = θ0).

The design method of the tilt antenna is the same as the conventional method of setting the phase so that the radio waves from the direction of the angle θ are in-phase combined at the feeding point (the insertion portion of the shaft 11 in FIG. 1B). By using, it is possible to use the direction of the maximum gain of each antenna element 14 at the time of beam tilt, and it is possible to realize a highly efficient tilt antenna regardless of the size of the tilt angle.

Note that this radio wave synthesizing unit radiates, for example, as shown in FIG. 3, by using the antenna plate 12 as a dielectric (relative permittivity ε) and providing a microstrip line on the bottom surface thereof, a triplate, or the like. It is not limited to the waveguide. Further, the array of the antenna elements 14 is arbitrary, such as a circle, a square, a rectangle, and the like arranged concentrically and multiply.

In the above structure, when the vehicle-mounted antenna 10 is mounted on a vehicle body (not shown) and the vehicle travels, the rotation drive control means 13 detects the movement of the vehicle body and rotates the gear 13a to rotate the gear. By receiving and rotating the antenna plate 12, the directivity to the satellite is maintained.

At this time, since the antenna plate 12 rotates horizontally about the shaft 11, it does not require a space larger than the currently installed space, and the antenna plate 12 is installed substantially horizontally. However, the influence of wind pressure during driving is minimized, and the height restriction is not significantly sacrificed.

[0021]

[Effect of device]

 As described above, the in-vehicle antenna of the present invention includes an antenna plate that is mounted on the vehicle body substantially horizontally via the shaft and that rotates in a plane substantially parallel to the horizontal plane via the rotation drive control means. Since the antenna plate is provided with an antenna element that is tilted at a predetermined angle, it is thin and can be installed in a small installation space, but it is not easily affected by wind pressure and the beam tilt High efficiency can be obtained even if the angle is large.

[Brief description of drawings]

1A and 1B show a vehicle-mounted antenna of the present invention, in which FIG. 1A is a perspective view of a main part, and FIG. 1B is a front view of the main part.

FIG. 2 shows an example of an antenna element used in the present invention,
(A) is a helical element, (B) is a curl element, and (C) is a three-dimensional element.

FIG. 3 is a sectional view of an essential part showing another embodiment of the vehicle-mounted antenna of the present invention.

FIG. 4 is a perspective view of a main part showing a conventional vehicle-mounted antenna.

[Explanation of symbols]

 10 ... In-vehicle antenna 11 ... Shaft 12 ... Antenna plate 13 ... Rotation drive control means 14 ... Antenna element

Claims (1)

[Scope of utility model registration request] 1. An antenna plate which is mounted on a vehicle body substantially horizontally via an axis and which rotates in a plane substantially parallel to a horizontal plane via a rotation drive control means, and an antenna plate which is inclined to the antenna plate at a predetermined angle. A vehicle-mounted antenna, comprising: