JPS63124605A - On-vehicle antenna system - Google Patents

Abstract

PURPOSE:To obtain a practically sufficient reception performance without a projecting antenna part at the outside of a vehicle by arranging a plate metallic body to an outer side lower face of a car body with a gap by an insulator and connecting a feeder end to the metallic body and the car body respectively. CONSTITUTION:An antenna 11 is provided with a metallic plate 11 being an antenna element. The surface of the metallic plate 11a is coated by an insulator 11b made of a reinforced plastic such as FRP and arranged to a face of the lower part 13 of a rear trunk with a prescribed gap. That is, the car body 12 and the metallic plate 11a are insulated electrically and a core wire is connected to the metallic plate 11a, the outer conductor of one end of the feeder 14 such as a coaxial cable is connected to the car body 12 and the other end is connected to a receiver. Thus, since the the metallic plate 11a being the antenna element is arranged to the outer side face of the car body 12, the external appearance of the car body is not deteriorated and no wind break noise is caused and noise from a microcomputer in the car body and a heater or the like is shielded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a vehicle antenna device that is mounted on a vehicle such as an automobile and receives radio waves in the medium wave band.

[Prior art and its drawbacks] In general, antennas for vehicles such as automobiles include a rondo antenna made of metal pipes connected together, a pillar antenna, a window glass antenna with a conductor pasted on the window glass, and a trunk part of the car body used as an antenna. Trunk antennas and the like that are used are known.

Although the above-mentioned rondo antenna and pillar antenna have relatively high sensitivity, they have problems in appearance, are easily damaged, generate large wind noise while driving, and have drawbacks such as inconvenience in expanding and contracting the antenna.

In addition, the above window glass antenna and trunk antenna are
Since it does not protrude from the vehicle body, it looks good and does not generate wind noise, but it has the disadvantage of low sensitivity. In particular, window glass antennas tend to pick up noise from the heat rays used for defogging and the microcomputer inside the car, which has the drawback of lowering reception sensitivity and impeding visibility.

Furthermore, modern vehicles not only have radios, but also televisions,
Since various antennas are required such as personal radio,
There are disadvantages such as deterioration in appearance due to the protrusion of a large number of antennas and generation of wind noise when driving.

[Object of the Invention] The present invention was made in view of the above-mentioned drawbacks, and an object of the present invention is to provide an antenna device for a vehicle that can obtain practically sufficient reception performance without being installed protruding from the outside of the vehicle. shall be.

[Key Points of the Invention In other words, the antenna device for a vehicle according to the present invention includes a plate-shaped metal body disposed on the outer lower surface of the vehicle body with a gap formed by an insulating material, and a power supply to the metal body and the vehicle body, respectively. It is constructed by connecting the 1f end portions.

[Embodiments of the invention] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows its external configuration from the bottom side of the vehicle body, and this antenna 11 is installed on the lower part 13 of the rear trunk of the metal vehicle body 12.

FIG. 2 shows a cross-sectional configuration taken along the line ■-■ in FIG. 1, and the antenna 11 includes a metal plate 11a serving as an antenna element. The surface of this metal plate 11a is coated with an insulating material 11b made of reinforced plastic such as FRP,
It is arranged on the lower 13 surface of the rear trunk with a predetermined gap (3 to 6α). That is, the car body 12 and the metal plate 11a are electrically insulated, and the outer conductor at one end of the power supply line 14, such as a coaxial cable, is connected to the car body 12, the core wire is connected to the metal plate 11a, and the other end The receiver R (not shown) is connected to the receiver R (not shown). Here, the antenna 11 coated with the insulating material 11b is fixed to the vehicle body 12 with screws, strong adhesive, or the like.

That is, according to the antenna device having the above configuration, the antenna 1
1 does not protrude from the outside of the car body 12, and the metal plate 11a itself serving as the antenna element is arranged on the outside surface of the car body 12, so the appearance of the car body does not deteriorate and wind noise is not generated. It is possible to shield noise from microcomputers in the car, heat rays, etc., and a sufficient induced voltage of 1 can be generated for the received signal. Furthermore, if the antenna 11 is installed on the lower surface 13 of the vehicle body, the roof section can be designed more freely than when installed on the upper surface of the vehicle body, for example on the roof, and painting and surface finishing treatments are easier.
Cost reduction becomes possible.

Here, as shown in FIGS. 3 and 4, the metal plate 11a as the antenna element has a length L1=8907M,
Width 81-300m, grid-shaped width L2-28m, length 8
The reception sensitivity of this antenna 11 is compared to that of the conventional Rondo antenna with a length of 1.14 m when it is constructed using extended band metal of 2-16 feet and the average gap with the vehicle body 12 is 35 feet. Then, the reception frequency is 0 (d b) at 594 (klh) and +2 (db) at 954 (kHz).
, 1197 (K city) and -1 (db), and although there are slight variations at each frequency, it can be seen that, on average, sufficient reception sensitivity is obtained that is equal to or higher than that of the conventional Rondo antenna.

In the above embodiment, the antenna 11 is installed on the lower surface of the rear trunk, but for example, as shown in FIG. 5, it can be installed on the lower surface of a single compartment! You may. Furthermore, if this antenna 11 is installed under a gasoline tank, hydraulic pipe, etc., the antenna itself will protect them and improve safety.

Further, the metal plate 11a serving as the antenna element may be donut-shaped as shown in FIG. 6, or a metal plate 11a with a large hole as shown in FIG. It is sufficient if the required area can be obtained with a predetermined gap.

In other words, if it is a planar shape, it can be configured in various shapes.

Furthermore, in the above embodiment, the insulating material 11b is attached to the metal plate 11a.
Although a gap with the vehicle body 12 is maintained and fixed by coating, if a predetermined gap is obtained between the vehicle body 12 and the vehicle body 12, it may be fixed via an insulating bushing or the like, for example.

[Effects of the Invention] As described above, according to the present invention, a plate-shaped metal body serving as an antenna element is disposed on the outer lower surface of the vehicle body with a gap formed by an insulator, and the metal body and the vehicle body are On the other hand, since the feeding end portions are connected to each other, it is possible to provide a vehicle antenna device that can obtain practically sufficient reception performance without the antenna portion protruding from the outside of the vehicle.

[Brief explanation of the drawing]

The first factor is a diagram showing a vehicle antenna device according to an embodiment of the present invention viewed from the underside of the vehicle body, FIG. 2 is a sectional view taken along the If-IF line showing the vehicle antenna device in FIG. 1, and FIG. 4 and 4 respectively show the shape of the metal plate in the antenna device of the vehicle, FIG. 5 shows the antenna installation position according to another embodiment of the present invention, and FIGS. 6 and 7 respectively It is a figure which shows the metal plate shape by another Example. 11... Antenna, 11a... Metal plate, 11b...
・Insulating material, 12... Vehicle body, 13... Vehicle body lower surface, 14
...Power line. Applicant's agent Patent attorney Takehiko Suzue Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] It is characterized by comprising a metal car body, a plate-shaped metal body disposed with a gap on the outer lower surface of the car body, and a power supply line whose ends are connected to the metal body and the car body. Antenna equipment for vehicles with