JPH032977Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to an antenna device for an on-vehicle radio receiver that utilizes an automobile body made of a conductive structure.

(Prior Art) Generally, as an antenna device for a vehicle-mounted radio receiver, there is a rod antenna protruding from a vehicle body, a glass antenna in which an antenna pattern is arranged on a rear window, or the like. This rod antenna has excellent electrical performance, but because it protrudes from the vehicle body, it has mechanical properties, such as being susceptible to bending and rust, and because it protrudes to the outside, it lacks safety. In addition, glass antennas do not protrude from the vehicle body in any way and improve the mechanical performance problems of the rod antennas mentioned above, but since they are placed in a limited space such as the rear window, they do not necessarily have sufficient electrical performance. I can not say.

Therefore, a ferrite core around which a pick-up coil is wound is placed inside the pillar so as to be perpendicular to the longitudinal axis of the pillar, and the output of this pick-up coil is input to the antenna of the in-vehicle radio receiver via a coaxial cable. An antenna device that provides the following is proposed in Japanese Utility Model Publication No. 53-34826.
This technology attempts to effectively utilize radio waves received by a car body made of a conductive structure. High-frequency signals induced by radio waves received at the car roof flow to the body via the pillars,
It also flows into the ground. Therefore, a pick-up coil picks up the signal induced by the high-frequency signal flowing through the pillar and supplies it to the in-vehicle radio receiver as an antenna input.

(Problems to be solved by the invention) The technology proposed in the above-mentioned Japanese Utility Model Publication No. 53-34826 has the advantage that it has no directivity, is not affected by the surrounding environment, and does not protrude outside the vehicle body. It is something that

However, since the rod-shaped ferrite core is disposed inside the pillar so as to be perpendicular to the vertical axis direction, the length of the ferrite core is limited to the width of the pillar even if it is the longest due to aesthetic reasons, which does not allow for free design. However, it is not possible to obtain a sufficiently satisfactory receiving sensitivity. Furthermore, since the output of the pickup coil is directly given to the vehicle radio receiver via the coaxial cable, the signal-to-noise ratio is likely to deteriorate due to transmission loss in the coaxial cable.

The purpose of the present invention was made in view of the above-mentioned conventional circumstances, and it is an antenna device for an in-vehicle radio receiver that has high reception sensitivity and an excellent signal-to-noise ratio, using a rod-shaped ferrite core around which a pick-up coil is wound. It is about providing.

(Means for Solving the Problem) In order to achieve this object, the present invention provides an antenna device for an in-vehicle radio receiver, in which a rod-shaped ferrite core around which a pick-up coil is wound is attached to the roof of the vehicle body near the connection point with the pillar. A booster is arranged near the ferrite core, and the booster amplifies the output of the pick-up coil and supplies it to the in-vehicle radio receiver via a coaxial cable. .

(Function) Since the rod-shaped ferrite core around which the pick-up coil is wound is arranged along the inside of the vehicle roof near the connection point with the pillar, radio waves received at the vehicle roof not only transmit high-frequency signals to the pillar, but also other signals. The pick-up coil can also pick up signals induced by high-frequency signals flowing through the pillars, and the length of the rod-shaped ferrite core is not limited and can be designed freely, making it possible to achieve high reception sensitivity. . In addition, since the output of the pick-up coil is amplified by a booster placed near the ferrite core and fed to the in-vehicle radio receiver as an antenna input via a coaxial cable, the signal-to-noise ratio is It is possible to make it excellent.

(Description of Embodiments) Hereinafter, embodiments of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram of an embodiment of the antenna device for a vehicle-mounted radio receiver of the present invention.

In FIG. 1, there is a T-shape along the inside of the vehicle body roof 1 and in the axial direction of the front pillar 2 near the connection point between the vehicle body roof 1 made of a conductive structure and one of the front pillars 2. A rod-shaped ferrite core 4 around which a pick-up coil 3 is wound is disposed so as to be orthogonal to the ferrite core. Furthermore, this ferrite core 4
A booster 5 is disposed near the pick-up coil 3, and the output of the pickup coil 3 is amplified by the booster 5 and fed to an on-vehicle radio receiver 7 as an antenna input via a coaxial cable 6.

By the way, high-frequency signals induced by radio waves received at the vehicle roof 1 flow to the body via one front pillar 2 (indicated by a solid arrow), and also flow toward the other front pillar or rear pillar, etc. also flows (indicated by the dashed arrow).

Therefore, the pick-up coil 3 of the ferrite core 4, which is arranged along the inside of the vehicle roof 1 near the connection point of one front pillar 2, is connected to the front pillar 2.
It is possible to pick up not only signals induced by high frequency signals flowing toward the other front pillar or rear pillar, etc., but also signals induced by high frequency signals flowing toward the other front pillar or rear pillar, etc., making it possible to efficiently receive radio waves. . Furthermore, unlike the conventional device, the length of the ferrite core 4 can be designed to an optimal length without any restrictions, and reception sensitivity can be increased.

Further, since the output of the pickup coil 3 is amplified by the booster 5 disposed nearby, the signal-to-noise ratio can be made sufficiently excellent even if there is a transmission loss due to the coaxial cable 6 or the like.

FIG. 2 is a schematic diagram of another embodiment of the antenna device for a vehicle-mounted radio receiver of the present invention. What is shown in FIG. 2 is two rod-shaped ferrite cores 14, 14.
orthogonal to the car body roof 1 and one front pillar 2.
It is arranged along the inside of the vehicle roof 1 near the connection point with the vehicle body roof 1. Pickup coils 13, 13 are wound around the two rod-shaped ferrite cores 14, 14, respectively, and electrically connected in series. This orthogonal pick-up coil 1
3 and 13, it is possible to efficiently pick up high frequency signals flowing not only to one front pillar 2 but also to the other front pillar and rear pillar, and the reception sensitivity is further improved compared to the one shown in Figure 1. can be done.

In the above embodiment, a ferrite core 4, around which pick-up coils 3, 13, 13 are wound, is placed near the connection point between one front pillar 2 and the vehicle roof 1.
14, 14 are provided, but it goes without saying that they may be provided near the connection point between the rear pillar and the vehicle body roof 1. In addition, pick-up coils 3 and 3 are installed near the connection points between the left and right front pillars and the vehicle roof 1, respectively.
Alternatively, ferrite cores 4, 4 wound with ferrite cores 4, 4 may be provided. At these multiple locations, pick up coil 3,
When arranging the ferrite cores 4, 4 wound with ferrite cores 3, as shown in Fig. 3, boosters 5, 5 are arranged near each, and the outputs amplified by the boosters 5, 5 are added together to form a single core. It is given as an antenna input to an in-vehicle radio receiver 7 via a coaxial cable 6 .

(Effects of the invention) As explained above, according to the antenna device for an in-vehicle radio receiver of the invention, the rod-shaped ferrite core around which the pick-up coil is wound is placed along the inside of the vehicle roof near the connection point with the pillar. The pick-up coil can pick up not only high-frequency signals flowing to the pillar due to radio waves received on the roof of the vehicle, but also signals induced by high-frequency signals flowing through other pillars. The length dimension is not limited and can be freely designed, and the reception sensitivity can be high. In addition, since the output of the pick-up coil is amplified by a booster placed near the ferrite core and fed to the in-vehicle radio receiver as an antenna input via a coaxial cable, the signal-to-noise ratio is It has the extraordinary effect of making it superior.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of one embodiment of the antenna device for a vehicle-mounted radio receiver of the present invention, and FIG. 2 is a schematic diagram of another embodiment of the antenna device for a vehicle-mounted radio receiver of the present invention. , FIG. 3 is a circuit diagram when pickup coils and the like are arranged at a plurality of locations. 1: Vehicle roof, 2: Pillar, 3, 13: Pick-up coil, 4, 14: Rod-shaped ferrite core,
5: Booster, 6: Coaxial cable, 7: Car radio receiver.

Claims (1)

[Scope of utility model registration request] A rod-shaped ferrite core around which a pick-up coil is wound is arranged along the inside of the vehicle roof near the connection point with the pillar, a booster is arranged near this ferrite core, and the output of the pick-up coil is transferred to the booster. 1. An antenna device for a vehicle-mounted radio receiver, characterized in that the antenna device is configured to amplify the signal and provide the signal to the vehicle-mounted radio receiver via a coaxial cable.