JPS59200503A - Antenna for vehicle - Google Patents

Abstract

PURPOSE:To reduce the height of an antenna for a vehicle by forming the antenna by using two metallic disks which are arranged in parallel. CONSTITUTION:A metallic disk 22 having a diameter D<phi> is fitted through an insulating ring 21c to a connector 21 fixed to the roof 11 of a vehicle. A metallic rod 23 is fitted in the hollow part of the insulating ring 21c. A metallic disk 24 having a diameter d<phi> is fixed to the other terminal of this rod 23 and forms a horizontal opening surface uniformly over the entire horizontal circumference together with the disk 22. Metallic rods 25 are stood vertically at the outer circumference part of the disk 24 at equal intervals, and their other-side terminals are fixed to the disk 22 to support both disks and also perform the matching of input resistance. Thus, the antenna 20 is formed to reduce the height of the antenna for the vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to antennas for various transmitting/receiving devices such as radios, radios, televisions, etc. The present invention relates to a vehicle antenna suitable for use in a transmitting/receiving device.

Conventionally, this type of vehicle antenna includes, for example, a vertical whip antenna that extends upward from a portion of a vehicle body, or a modified antenna thereof. however,
The axial length of such an antenna is usually 50 cm or more, which means that the antenna extends high from the surface of the vehicle body, and as a result, while the vehicle is running, it may come into contact with low-lying bridge girders, etc. The antenna may be damaged due to
Alternatively, various problems arise, such as the need to temporarily remove the antenna from the vehicle body when the vehicle is parked in a garage or when an automatic car wash is performed.

The present invention has been made to address these problems.
The purpose is to provide a low-height vehicle antenna that has the same transmitting and receiving functions as the above-mentioned vertical whip antenna or its modified antenna.

In order to achieve such an object, the configuration of the present invention is to provide a short axis length that is erected outwardly on a part of the outer wall of the vehicle so as to be connected to a transmitting device or a receiving device installed in the cabin of the vehicle. a metal rod, and a first metal circle supported substantially horizontally at the tip of the metal rod and having a diameter determined in relation to the wavelength of a signal transmitted from the transmitter or the wavelength of a signal received by the receiver. a second metal disk, which is supported by the metal rod through an electrically insulating member on the underside of the first metal disk and parallel to the first metal disk, and has a diameter determined in relation to the transmitted signal wavelength or the received signal wavelength; two metal disks; and an outer peripheral portion of the first metal disk, which is vertically disposed on the second metal disk at approximately equal intervals along a circumferential portion corresponding to the outer peripheral portion of the first metal disk. and at least two auxiliary metal rods that support the input resistor at each upper end and perform input resistance matching.

By configuring the present invention in this way, the horizontal opening surface is uniformly formed between the first and second metal disks over the entire circumference thereof, and the input of each of the auxiliary metal rods is made uniform. Based on the resistance matching effect, it is possible to ensure omnidirectionality in the horizontal direction similar to that of conventional frame-type antennas, and because the main metal rod has a short axis length, it protrudes from the outer wall of the vehicle compared to conventional frame-type antennas. The degree of
As a result, while the vehicle is running, it will not come into contact with objects around it and be damaged, and it will not get in the way when the vehicle is parked in a garage or when it is being automatically washed. Furthermore, since at least two of the auxiliary metal rods are employed and are arranged at approximately equal intervals between the two metal disks, this type of antenna becomes even more robust. Furthermore, when attaching each of the auxiliary metal rods to both of the metal discs, each auxiliary metal rod is suspended over the second metal disc at approximately equal intervals in line with the outer periphery of the first metal disc. Since it is only necessary to install the input resistor, the installation work can be easily performed, and input resistance matching can also be facilitated.

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings.
The figure shows that an antenna 20 according to the present invention is installed on a roof 11 of a vehicle 10.
It is shown mounted approximately in the center of the The antenna 20 is for a personal radio placed in the cabin of the vehicle 10, and has a connector 21, as shown in FIG.
12 is positioned parallel to the roof 11 and is fixed to the approximate center of the roof 11 at the base 21b via a metal attachment (not shown). Collar part 21111 of connector 21
, a metal disk 22 having a diameter Dφ connects a through hole 222 provided at its center from the connector 21 to the flange 21112.
The insulating ring 21C is fitted onto the outer periphery of the insulating ring 21C that protrudes through the insulating ring 21C, and is fixedly connected to the ground via the flange 21a, the main body of the connector 21, the attachment, and the vehicle 10.

The metal rod 26 has its base connected to the insulating ring 21 of the connector 21.
The metal rod 23 is fitted into the hollow part of C and is assembled to the connector 21 so as to protrude perpendicularly from the metal disk 22 by a height H (referred to as effective height H). The base of the metal rod 26 is connected to the power supply terminal of the personal radio via a coaxial cable (not shown).A metal disk 24 having a diameter dφ is connected to the metal disk 22 at the two ends of the metal rod 26. The four metal rods 25 to 25 are fixed at the center so as to be parallel to each other, and together with the metal disk 22, form a uniform horizontal opening surface over the entire horizontal circumference.The four metal rods 25 to 25 are In order to achieve horizontal omnidirectionality of the antenna 20 with high accuracy, input resistance matching is performed, and as shown in FIGS. 2 and 6, a metal disk 2
2, the metal disks 24 are vertically arranged at approximately equal intervals along the circumferential portion corresponding to the outer circumferential portion of the metal disk 24 of the metal disk 22, and the metal disks 24
is fixed to the outer circumference of the metal disk 24 to short-circuit the outer circumference of the metal disk 24 to the metal disk 22. Note that the metal disk 24 transmits and receives signals to and from the personal radio device via the metal rod 26 at its center.

In this embodiment configured as described above, the antenna 20
Regarding the size and shape of the personal radio and its main characteristics as an antenna, the radio frequency band (906-905 M
When we conducted an experiment regarding the relationship with Hz), we obtained the following results.

1. If the diameter of the metal disk 22 is Dφ200 ('#J, the diameter of the metal disk 24 is dφ-135 (jlM), and the effective height H of the metal rod 26 is 25 (my), then the antenna 20 is The characteristics are as follows.

2, Dφ = 190 (tomo), dφ = 137.
5 (tomo), H-'l 4 (WWI), and Dφ-
180 (home), dφ-140 (war), H=2
3 (mm), substantially the same characteristics as the above experimental results were obtained. However, from the results of the second experiment, the radio frequency of 900 MHz, which is close to 903 to 905 MHz.
When the wavelength of the frequency of Hz is λ, Dφ=0.54λ
〜0.6λ(sin), dφ−0,4λ〜0.42λ(Wx
), if H=0.069λ~0.075λ,
It has been found that the antenna 20 can exhibit characteristics as an antenna that are equal to or better than those of a conventional frame antenna.

In addition, in the embodiment, the diameter Dφ of the metal disk 22
〉An example was explained in which the diameter of the metal disk 24 was dφ, but if Dφ-dφ was used instead, substantially the same experimental results as in the above example could be obtained, except for a slight decrease in the absolute gain. It was done.

In the above embodiment, two metal discs 22.2
4 has been described, but instead of this, the metal disc 22 may be replaced by the roof 11 of the vehicle, and in such a case, dφ-120 (wing), H = 30 (shadow). As a result, substantially the same experimental results as in the previous example were obtained, except that the absolute gain increased by about 7 dB.

Further, in the embodiment, the antenna 20 is connected to the vehicle 10.
An example was explained in which it was installed in the center of the roof 11 of
The present invention is not limited to this, and the attachment location of the antenna 20 to the vehicle 10 may be changed as appropriate. In such a case, the connector 21 may be omitted and the coaxial cable may be directly connected to the base of the metal rod 26.

Further, in the above embodiment, the four metal rods 25 are used as a means for short-circuiting the outer circumference of the metal disk 24 to the metal disk 22 to improve the matching degree of input impedance of the antenna 20. However, instead of this, it may be implemented using, for example, five metal rods 25. In such a case, the above-mentioned configuration may be implemented, except that the diameters of both metal disks 22, 24 are somewhat larger. Substantially the same characteristics as in the example are obtained. Note that the number of metal rods 25 may be reduced, and in this case, at least two metal rods are sufficient.

In the above embodiment, an example was explained in which the antenna 20 was configured for a personal radio, but the present invention is not limited to this, and the present invention may also be applied to a car radio or other vehicle receiver. In such a case, each diameter Dφ, dφ and effective height H may be changed as appropriate depending on the reception frequency of each receiver.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the antenna according to the present invention installed on the roof of a vehicle, FIG. 2 is a partially cutaway surface view of the antenna in FIG. 1, and FIG. 6 is a diagram showing the antenna in FIG. 1. The plan view and FIG. 4 are characteristic curve diagrams showing the relationship between the antenna standing wave ratio (V, S, W, R,) and the fouling coefficient 1r71 in FIG. 1 and the radio frequency. FIG. 1 is a characteristic curve diagram showing the horizontal plane directional electric field pattern of the antenna, and FIG. 6 is a characteristic curve diagram showing the vertical plane directional electric field pattern of the antenna. Description of symbols 10... Vehicle, 11... ffi root, 20... Antenna, 21... Connector, 21c... Insulating ring, 26
... Metal rod, 22.24 ... Metal disk, 25.
...Metal rod. Applicant Nippondenso Co., Ltd. Agent Patent Attorney Teru Hase - Procedural Amendment (Radio) Commissioner of the Japan Patent Office Kazuo Wakasugi 1. Case Description ■Death 1958 Patent Application No. 74722 Showa No.
No. 2, Name of the invention Vehicle antenna 3, Relationship with the case of the person making the amendment Patent Applicant address Name (42/)) Nippondenso Co., Ltd. Ryoshin
Building 6, drawing to be corrected 7, contents of correction +11 Drawing box 5 and 6 will be corrected as shown in the attached sheet. 8. List of attached documents (1) Drawings (Figures 5 and 6) 1 sheet (
2)

Claims (1)

[Claims] A main metal rod with a short axis length that is erected outward on a part of the outer wall of the vehicle so as to be connected to a transmitting device or a receiving device installed in the vehicle interior, and a tip end of the main metal rod. a first metal disk supported substantially horizontally by the transmitter and having a diameter determined in relation to the wavelength of a signal transmitted from the transmitter or the wavelength of a signal received by the receiver; a second metal disk supported by the main metal rod via an electrically insulating member and having a diameter determined in relation to the transmitting signal wavelength or the receiving signal wavelength; Input resistors are provided vertically on the disk at approximately equal intervals along a circumferential portion corresponding to the outer circumferential portion of the first metal disk, and support the outer circumferential portion of the first metal disk at each upper end. and at least two auxiliary metal rods that perform a matching function.