JPS6146601A - Antenna for automobile - Google Patents

Abstract

PURPOSE:To provide incorporatedly two antennas of a different frequency band to an automobile by providing the 1st antenna section to the tip of a coaxial line and constituting the 2nd antenna section with an outer conductor of the coaxial and a metallic body of the automobile. CONSTITUTION:The coaxial line 1 is projected vertically from the metallic body 2 of the automobile in an insulated state and a rod 3 having a length of nearly 8cm corresponding to a 1/4 wavelength of a band of a personal radio equipment while being coupled with the center conducror 1a is provided to the tip, being projected upright. Further, a pottery tube 4 having a length of 8cm and a structurefolding an outer conductor 1b is provided to the peripheral part of the tip and they constitute an antenna section 5 for personal radio equipment. Further, the length of a part of the coaxial line 1 projected from the metallic body 2 is set to nearly 90cm being a 1/4 wavelength of an FM frequency band and the outer conductor 1b constitutes an AM/FM antenna section 6 using the body 2 as ground. Thus, the antenna for automobile operated for two different frequency bands is constituted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automotive antenna used primarily for receiving radio broadcasts, transmitting and receiving radio signals, etc. on a vehicle.

(Prior art) In recent years, the frequency band used is called Vernal radio.
As small in-vehicle radios with a frequency of 3 to 905 MHz have become popular, automobiles equipped with this personal AK are equipped with an AM/FM radio consisting of a Rondo antenna with a length of about 90 to 110 cnL, as shown in Figure 4. In addition to the vehicle antenna 14, a Franklin antenna or a Ranal Burnal radio antenna 15, for example, with a length of approximately 70 CIn, is installed on the vehicle body. However, since such an antenna protrudes long from the vehicle body, it is necessary to store or remove it each time the antenna is washed with charcoal (automatic car wash) or when entering the garage. For this reason, as the number of antennas increases, the effort described above increases.
It is hoped that an automotive antenna that can be applied to both AM/FM radio and personal radio will emerge.

Therefore, conventionally, a coaxial line is formed using the waveguide outer frame of a horn-shaped antenna as a coaxial inner conductor, and the opening outer frame of this horn-shaped antenna is used as a radiating element to couple the coaxial line. Antenna (Japanese Unexamined Patent Publication No. 57-168506
However, such an antenna is a VC antenna that is attached to the outside of the vehicle body and used for receiving radio broadcasts, transmitting and receiving personal radio, etc.
is inappropriate due to operating characteristics such as frequency band and structural problems.

(Problems to be Solved by the Invention) As described above, in the conventional automobile antenna, the antenna for AM1M radio and the antenna for personal radio are provided separately, and An antenna operating in two different frequency bands in a
Since it is not suitable as an automotive antenna, the present invention provides a complete automotive antenna that can operate in two different frequency bands, e.g. AM/'FM radio and personal radio, by providing a complete automotive antenna that can operate in two different frequency bands, for example, AM/'FM radio and personal radio. This is intended to prevent an increase in the number of automobile antennas due to the installation of antennas, and to reduce the trouble of attaching and detaching the antennas when washing the car or entering the garage.

(Means for Solving All Problems) 1. In order to solve the above problems, the present invention provides a first antenna section that operates in a first frequency band at the tip of a coaxial line, and Outer conductor? By using it as an antenna element and configuring a second antenna part that operates in a second frequency band between the outer conductor and the metal body of the automobile, it is possible to operate in mutually different frequency bands. Two antenna parts? It constitutes an integrated automobile antenna.

(Example) Hereinafter, embodiments of the present invention will be explained in detail with reference to the drawings.

FIG. 1 and FIG. 2 are diagrams showing the configuration of an embodiment of the present invention. As shown in FIGS. 1 and 2, 1 is a coaxial line installed such that one end thereof projects vertically upward from the metal body 2 of the NtJ vehicle, and is insulated from the metal body 2. At the tip of the coaxial line 1 protruding from the metal body 2, there is a conductor of about 8α, which is electrically connected to the center conductor 1a and corresponds to about 1/4 wavelength of radio waves of 903 to 905 MHz, which is the frequency band used by personal radios. A long metal rod 3 is provided to protrude upward, and an outer conductor 11+ is provided on the outer periphery of the tip.
The length of the i-folded structure is also about 80! rL tube 4 is provided, and these metal rods 3 and tube 4
These constitute a personal radio antenna section 5. Further, the length of the coaxial line 1 that protrudes from the metal body 2 is 76 to 90 M, which is the frequency band used for 7M radio broadcasting.
The antenna part 6 for an AM/'FM radio is installed so that it has a length of about 90 Hz, which corresponds to about 174 ff length of a radio wave of Hz, and the outer conductor 1b of this coaxial line is connected to the metal body 2 of the car as the ground. It consists of The personal radio antenna section 5 is connected to the personal radio device 7 via the center conductor 1aB of the coaxial line 1 and the outer conductor 1b (z).
/FM radio antenna section 6 has a center conductor connected to the outer conductor 1b1 of the coaxial line 1, and the outer conductors connected to the metal body 2.
7' (connected to an AM/'FM radio receiver 9 via a coaxial line 8).

In the above configuration 2, the personal radio antenna section 5 has a lower end portion of the tunnel tube 4 located 10c from the metal body 2 of the automobile.
If the distance is more than IrL, it will function as an antenna regardless of the conduction or insulation between the outer conductor 1b of the coaxial line 1 and the metal body 2, and in this embodiment, the distance from the metal body 2 is 80 or more. Therefore, it has good circular directivity in a horizontal plane without being affected by the metal body 2. The tube 4 is provided to completely prevent leakage current from occurring in the outer conductor 1bK of the coaxial line 1, and to match the impedance of the personal radio 7 (50Ω).

In other words, in the AM/FM radio antenna section 6, the length of the outer conductor 1b of the coaxial line 1 serving as the antenna element protruding from the metal body 2 is set based on the wavelength of 7M radio broadcasting. 8 wholesale <7M radio antenna and AM
The radio antenna can be used for both AMB and FM.
Both radio broadcasts can be received well.

In addition, as an example of actually installing this embodiment in a car, as shown in Fig. 3 (a) and ('b), the part constituting the coaxial 11111 antenna is shaped like a rod made of resin. It is embedded in the member 10p'9 so that it can stand upright on the car, and the lower end of the rod-shaped member 10' has a threaded portion on the upper outer peripheral surface thereof. A cylindrical conductive stay 11 is fitted onto the outside of the metal and fixed, and ten rod-shaped members are fixed to the mounting bracket 13 by means of the stay 11 and a screw 12 that engages with the threaded portion thereof.

This mounting bracket 13 is a quiz type that is attached to a normally used trunk lid. Then, connect the coaxial line j2 to the personal radio, connect the center conductor of the coaxial line 8 to the outer conductor 1b of the coaxial line 1, and connect the outer conductor of the coaxial line 8 to the mounting bracket 1.
A stay 11 that is electrically connected to the metal body 2 of the automobile via 3.
The coaxial line 8 is connected to an AM/'FM radio receiver by soldering or the like, respectively.

2. As an example, an automotive antenna that operates in the frequency bands of personal radio and AM/FM radio has been described, but antennas that operate in two other different frequency bands can be constructed in the same way. requires a difference of at least three times the lower frequency band.

Further, in the above embodiment, the personal wireless antenna unit 5 is configured with a coaxial type antenna, but it may also be configured with a Brown antenna or the like.

(Effects of the Invention) As explained above, the present invention provides a first antenna part that operates in a first frequency band at the tip of a coaxial line, and uses the outer conductor of this coaxial line as an antenna element, A second antenna section that operates in a second frequency band using a metal body as a care ground? An automotive antenna that can be configured to operate in two different frequency bands with one antenna? Since it can be configured, it has the effect of completely preventing an increase in the number of automobile antennas due to the installation of a personal radio device.

[Brief explanation of drawings]

Fig. 1 and Fig. 2 are diagrams showing the configuration of an embodiment of the present invention U, and Fig. 3 (a) 2 and (bl) illustrate the installation of an embodiment of the present invention on an automobile. In the diagram for, Figure 4,
A car antenna? FIG. 1: Coaxial line, 1a: Center conductor 1b: Outer conductor 2: Metal potty 3: Metal rod 4: Tube 5: Personal radio antenna section 6: AM, etc.M tera radio antenna section 3 Figure 4

Claims (1)

[Scope of Claims] A first antenna portion corresponding to a first frequency band, disposed at the tip of a coaxial line and configured between a center conductor and an outer conductor of the coaxial line; 1. An antenna for an automobile, comprising: a second antenna portion corresponding to a second frequency band formed between the outer conductor and a metal body of the automobile by using a conductor.