JPS6342507A - Antenna system for automobile - Google Patents

Abstract

PURPOSE:To use a single ball-shaped antenna system in different frequency bands by connecting a frequency band separating element, which has a high impedance for a high frequency, between two conductors. CONSTITUTION:The first conductor 5 includes conductors 8, 8a, 9, and 10 arranged in order from the top. A loading coil 6 functions as the frequency band separating element which has a high impedance for a relatively high frequency band, and this coil 6 has a low impedance in case of a relatively low frequency band of radio broadcast. The second conductor 7 functions as a whip antenna in the frequency band of car telephone. A center conductor 13 of a coaxial cable 12 is connected to a base body 4, and its outer conductor 14 is connected to an automobile body 2. The coaxial cable 12 is connected to a radio receiver through a distributor 15 and a coaxial cable 16 and is connected to a transmitter-receiver for car telephone through a coaxial cable 17.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to an antenna device for an automobile, and more particularly to an antenna device for an automobile that can be used for radio broadcasting, automobile telephones, and the like.

BACKGROUND ART Traditionally, a radio broadcasting antenna and an automatic 11 telephone antenna have been separately installed on the body of an automobile. When these antennas are formed in the shape of a longitudinal bar, a plurality of antennas protrude from the vehicle body, resulting in a problem that the aesthetic appearance deteriorates and wind noise is generated during driving.

Problems to be Solved by the Invention An object of the present invention is to solve the problem of a longitudinal bar 7 protruding from the body of an automobile.
Self-gII which made it possible to reduce the number of antennas
An object of the present invention is to provide an antenna device for a J car.

Means for Solving the Problems The present invention comprises: a first longitudinal conductor; a frequency band separation element that is connected to the lower part of the first conductor and has a large impedance at high frequencies; and a frequency band separation element that is connected to the lower part of the element. a longitudinal second conductor, where only the second conductor is used as a 7 antenna for high frequencies, and at frequencies lower than those where the second conductor is used as a 7 antenna, the first conductor and the second conductor are This is a seven-antenna device for automobiles that is characterized by being used as a whip antenna.

A preferred high fI embodiment is characterized in that the second conductor is a whip antenna.

Even better implementation! ! , the second conductor is a vertical gouball antenna.

Function According to the present invention, the impedance of the element is small in a relatively low frequency band such as radio broadcasting, and therefore the first conductor and the second conductor can be used as a whip antenna. Relatively high frequency i! for car phones etc. 1. In the band, the element becomes a large impedance and therefore the second conductor is used as an antenna,
At this time, the traveling wave is prevented from being transmitted to the first conductor by the element. In this way, the overall shape can be made into a roughly elongated ball shape, which can be used in common in different frequency bands. Therefore, it becomes possible to reduce the number of antennas attached to the car body.

Embodiment FIG. 1 is a perspective view showing a seven-antenna assembly RA1 according to an embodiment of the present invention in an extended state, and FIG. 2 is a perspective view showing the antenna device 1 in a shortened state. This antenna
! cii! The top of the rear trunk of the metal car body 2 of the car is removed from the car body 1 and is used commonly for radio broadcast reception and car phone calls.

Figure 3 is an antenna! If! ! FIG. 1 is a vertical cross-sectional view showing the expanded state as in FIG. 1 of FIG. A metal base 4 in the shape of a right circular sieve is fixed to the vehicle body 2 via an electrical insulator 3 made of a material such as synthetic resin. The fourteenth body 5, the a-ding coil 6, and the second conductor 7 are housed in the base body 4 in a telescopic shape, so that it can be shortened as shown in FIG. 2 described above. The first conductor 5 is a conductor 8.8a in order from the top.
, 9.10, the loading coil 6 acts as a frequency A-band separation element that has a large impedance in a relatively high frequency band for car telephones, and has a small impedance in a relatively low frequency band for radio broadcasting. ing.

When the first conductor 5, the loading fill 6, the second conductor 7, and the wires of the loading coil 6 are stretched in a straight line, the total length is equal to the wavelength of the frequency band of radio broadcasting. 1, r length, and λ1/4.

λ1. 1F1=□ ...(1) In Japan, the frequency band of frequency modulation radio broadcasting is 7G-
90MHz and J? 1 is defined, for example, at about 90c. In this way, the first conductor 5 and the loading coil 6
and the second conductor 7 function as a whip antenna in the frequency band of radio broadcasting.

The length 2 of the second conductor 7 is determined to be 2/4, where λ2 is the wavelength of the frequency band for car telephones.

The length i2 corresponds to the frequency band for car phones of 860-940.
Since it is MHz, it is determined to be approximately 9ci*.

In this way, the second conductor 7 acts as a whip antenna in the frequency band 1 of the car telephone.

Conductor 8.3a when not receiving radio broadcasts.

9 can be abbreviated and placed in a constant standby state as described above in the frequency/band of the car phone.

The center conductor 13 of the coaxial cable 12 is connected to the base 4, and its outer conductor 14 is connected to the vehicle body 2! 1 will be given.

The coaxial cable 12 is connected to a radio receiver via a coaxial cable 16 via a distributor 15, and to a car telephone transceiver via a coaxial cable 17.

FIG. 4 shows an antenna arrangement according to another embodiment of the present invention! 119 is a perspective view showing the state when the antenna device 119 is extended, FIG. 5 is a perspective view showing the state when the antenna device 19 is shortened, and FIG. FIG. 3 is a longitudinal cross-sectional view of the device 19 when it is extended.

This embodiment is similar to the previous embodiment B, corresponding parts bear the same reference numerals, it should be noted that the automotive metal**
A base body 20 made of metal and formed into a right cylindrical shape is fixed to the body 2 . A first conductor 21, a loading coil 22, and a second conductor 23 are used for radio broadcast reception. The first conductor 21 includes expandable and contractible conductors 24 and 25.2G. The loading coil 22 has a similar configuration to the above-described loading coil 6, has a large impedance at high frequencies, and has a high frequency signal fjS1.
It is prevented from proceeding to the conductor 21 side.

The second conductor 23 includes conductors 27 and 28. The conductor 27 is storably attached to the base body 20 via a short cylindrical electrical insulator 29 made of synthetic resin or the like. A conductor 28 is connected to the base body 20 via a metal connecting member 30 extending radially outward. The inner conductor 13 of the coaxial cable 12 is electrically connected to the conductor 27, and the outer conductor 14
is electrically connected to the conductor 28 via the connecting member 30. In relatively low frequency bands such as radio broadcasting,
Assuming that the total length of the first conductor 21, the a-ding coil 22, and the conductor 27 of the second conductor 23 is 13 when the loading coil 22 is extended linearly, the frequency band of radio broadcasting is λ1. Then, it is determined as shown in the third equation.

The length of the conductor 27.28, ii' 4 'tZ A b, is the fourth wavelength λ2 of the frequency band of the car telephone.
It is determined according to the formula.

()4a+, 54L+) in the PISS formula is approximately 17
It is defined in cm.

Car I! without receiving radio broadcasts! When only four episodes are used, the first conductor 21 and the loading fill 22 can be shortened and stored in the second conductor 23. When not receiving radio broadcasts or performing car phone communication, First conductor 21, loading coil 2
2 and the conductor 27 are housed in the base body 20 to form the state shown in Fig. P2S5.

As described above, the loading coil 22 has a large impedance in the high frequency band of a car phone, and has as small an impedance as possible in a low frequency band of radio broadcasting. 8!
For example, a parallel resonant circuit may be formed by a fill and a floating capacitor, and the element may be configured to resonate in a high frequency band and have a large impedance. Good length in each of the above examples! 1 to 4 are changed as appropriate depending on the frequency used, and their wavelength inputs 1. It may be set to a value having another magnification of λ2.

Effects As described above, according to the present invention, a single ball-shaped antenna device can be used to transmit different frequencies! Since the vehicle can be shared by the & band, the aesthetic appearance is improved and the generation of wind noise during driving can be reduced by $11.

[Brief explanation of the drawing]

FIG. 1 shows an antenna device i! according to an embodiment of the present invention. 1 is a perspective view showing the extended state of the 7-antenna device 1, FIG. 3 is a perspective view showing the shortened state of the 7-antenna device 1, and FIG.
Fig. fi4 is a perspective view showing the extended state of the antenna device 19 of the embodiment of the present invention, Fig. 5 is a perspective view showing the antenna R219 in the shortened state, and Fig. 6 is a longitudinal cross-sectional view of No. be. 1. One thing...antenna device, two...vehicle body, 5.21
...first conductor, 6,22...loading coil,
7, 23...second conductor, 4,20...substrate agent
Patent Attorney Number of Strokes Keiichi Parts Figure 1 Figure 2 Figure 3 λ Figure 4 Figure 5 Figure 6x Procedural Amendment May 27, 1988 Patent Application 1987-187144 2. Title of Invention Automotive Antenna Device 3, Amendment Applicant Address: 1-2-28 Gosho-dori, Hyogo-ku, Kobe Name: Fujitsu Ten Ltd. Representative: Ishii Tairahe Department 4, Agent Address: 1-13-38 Nishihonmachi, Nishi-ku, Osaka City Emerging building country equipment EX 0525-5985 INTAPT
J International FAX GIII&Gn (06)538-
02476, Drawing 7 to be corrected, and Figure 6 of the drawings to be corrected are corrected as shown in the attached sheet. that's all

Claims (3)

[Claims] (1) A first longitudinal conductor, and a second longitudinal conductor connected to the lower part of the element for frequency band separation, which is connected to the lower part of the first conductor and has a large impedance at high frequencies; An antenna device for an automobile, characterized in that the first conductor and the second conductor are used as a whip antenna at frequencies lower than the frequency at which the second conductor is used as an antenna. (2) The antenna device for an automobile according to claim 1, wherein the second conductor is a whip antenna. (3) The antenna device for an automobile according to claim 1, wherein the second conductor is a vertical dipole antenna.