JPH08139514A - On-vehicle lens antenna - Google Patents

Abstract

PURPOSE: To obtain an on-vehicle antenna which is low in manufacturing cost and easy in assembling operation and has large resistance to a hostile by environment such as high-level vibration. CONSTITUTION: This antenna is equipped with a dielectric lens 11 which is formed of the same material with a vehicle bumper 10 of resin such as polypropylene, etc., and a primary radiator 13 which is arranged nearby the focus of this dielectric lens 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-vehicle antenna used for an on-vehicle millimeter-wave radar, and in particular, it is manufactured as an antenna by being integrated with a resin vehicle bumper. -The present invention relates to a dielectric lens antenna for a vehicle in which the cost of assembling is significantly reduced.

[0002]

2. Description of the Related Art On-vehicle radar devices include a laser radar device that uses laser light and a radio wave radar device that uses radio waves. Comparing the two, the radio wave radar device is superior in that it is resistant to adverse environments such as rain, snow and fog which are inherent in vehicles. Further, the FM radar and the AM radar methods are superior to the pulse radar method in that the distance measuring range includes a short range of several tens of cm. Further, the millimeter wave band having a short wavelength is used in order to reduce the size of the radar device, especially the antenna. Thus, the millimeter-wave band FM radar is one step ahead in the possibility of practical application.

[0003]

The radio wave radar device represented by the millimeter wave band FM radar device has a problem that the manufacturing cost of the device is lower than that of the laser radar.
As can be understood by referring to, for example, Japanese Patent Application Laid-Open No. 5-273339 (Japanese Patent Application No. 3-74758) related to the applicant's earlier application, the manufacturing cost of the antenna and the vehicle cost out of the manufacturing cost of the entire radar device. The cost of mounting the antenna to the occupies a considerable proportion. In particular, since the vehicle radar device is expected to be installed by the customer after purchasing the vehicle, it is considered inevitable to perform a complicated installation work in consideration of anti-vibration measures.

Accordingly, one object of the present invention is to provide a vehicle-mounted antenna which is inexpensive to manufacture and install on a vehicle. Another object of the present invention is to provide a highly reliable in-vehicle antenna that maintains its performance even in a bad environment peculiar to a vehicle such as high level vibration, a wide temperature range, dust, wind and rain.

[0005]

An on-vehicle lens antenna of the present invention which solves the above-mentioned problems of the prior art is made of the same material as a vehicle bumper made of a resin such as polypropylene, and from the back surface of the vehicle bumper. It comprises a raised dielectric lens and a primary radiator arranged near the focal point of the dielectric lens.

[0006]

In the past, most vehicle bumpers made of metal were used, but nowadays, bumpers made of resin are mainly used. A dielectric lens such as a plano-convex lens is formed by elevating the resin (dielectric) that is the material from the back surface of the bumper into a lens shape. By placing the primary radiator in the vicinity of the focal point of the dielectric lens, the vehicle-mounted lens antenna can be formed extremely easily. Hereinafter, the present invention will be described in more detail with reference to Examples.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an exploded perspective view (A) showing the structure of a vehicle-mounted lens antenna according to an embodiment of the present invention and a sectional view (B) showing a state of use after assembly, in which 10 is polypropylene. Is a resin bumper made of resin, 11 is a dielectric lens, 12 is a stay, 13 is a planar antenna, 14 is a dielectric substrate, 15 and 16 are connectors, and 17 is a coaxial cable.

The dielectric lens 11 is made of polypropylene (dielectric) and is made of polypropylene surrounded by a curved surface portion protruding from the rear surface of the vehicle bumper 10 and a circular flat portion shown by a dotted line on the rear surface of the vehicle bumper 10. It is composed of a plano-convex lens as a material. Similarly, stay 12
Is also made of polypropylene having a cylindrical shape that is raised from the back surface of the vehicle bumper 10 made of polypropylene so as to surround the dielectric lens 11. In each case, the polypropylene vehicle bumper 10, the dielectric lens 11 and the stay 12 are integrally formed by injection molding for manufacturing the vehicle bumper 10.

The dielectric lens antenna itself is known from JP-A-51-1006664, and the dielectric lens itself made of polypropylene is known from JP-B-59-23483. There is.

Planar antenna 1 acting as a primary radiator
3 is formed in the central portion of a disk-shaped dielectric substrate 14, and when the peripheral portion of the dielectric substrate 14 is fixed on the cylindrical stay 12 via an adhesive, the dielectric lens 3 is formed. It is arranged near the focal point of 11. The planar antenna 13 includes a microstrip line extending from a central portion of the dielectric substrate 12 to a peripheral portion thereof, a coaxial connector 15 mounted on the peripheral portion of the dielectric substrate 12, and a coaxial screwed to the coaxial connector 15. Connector 16 and coaxial cable 1
7 and a main body portion (not shown) including an FM signal generator and a mixer. Typical millimeter wave FM
When configuring a radar device, the planar antenna 13
Emits an FM signal in the millimeter wave band and receives its reflected wave.

For a detailed example of such a planar antenna, the specification of Japanese Patent Application No. 6-109041 entitled "Microstrip Patch Antenna" previously filed by the applicant of the present invention, etc. may be used as necessary. Please refer. Further, as disclosed in the specification of the patent application entitled "Radar Module" previously filed by the present applicant, a plurality of planar array antennas having different tilt angles are formed as primary radiators, It is also possible to adopt a configuration in which the beam is substantially scanned by selectively switching these.

FIG. 2 is a perspective view showing a vehicle-mounted lens antenna according to another embodiment of the present invention in which a plurality of dielectric lenses and stays are formed along the length direction of a vehicle bumper. Seven dielectric lenses 11 along the length of the vehicle bumper 10
a to 11 g are formed, and seven cylindrical stays 12 a to 12 g are formed so as to surround each dielectric lens. The number of antennas used varies depending on the type of radar device installed in the vehicle. In this case, the maximum number of dielectric lenses and stays are made integrally with the vehicle bumper so as to be compatible with the radar device that uses the maximum number of antennas, and the actual number of dielectric lenses and stays is actually set according to the type of the radar device to be mounted. The primary radiator should be attached to only what is needed.

Further, the bumper for a vehicle is installed in advance even in a vehicle in which the radar device is not mounted at the time of selling the vehicle body. In this way, it is possible to add antennas very easily by the simple operation of adding the primary radiator in response to the customer's demand after the sale. Since the space occupied by the stay on the back surface of the vehicle bumper is small, the space wasted when the radar device is not mounted is relatively small. In addition, since the vehicle bumper does not have any cutouts such as cutouts and has a reinforcing structure with a dielectric lens and stay added, the mechanical strength of the vehicle bumper is rather increased. improves.

Although the structure in which the dielectric substrate on which the primary radiator is formed is adhered and fixed onto the stay has been described above, the structure may be performed by screwing or fitting.

Although the stay has a cylindrical shape,
Of course, any other suitable shape that facilitates injection molding may be adopted. Further, if the problem of dust prevention is not a problem, the stay may not be closed and the post may be composed of two to three or more posts which are discretely arranged at equal intervals on the circumference. Alternatively, it is possible to adopt a configuration in which the primary radiator is fixed to the center of the dielectric lens by adhesion without forming the stay itself.

Further, although the case where the planar antenna is used as the primary radiator is illustrated, other suitable primary radiators such as a horn can be used.

Although polypropylene having a small dielectric loss has been exemplified as the resin, if the dielectric loss can be increased to some extent, another cheaper resin can be used as a material.

[0018]

As described in detail above, the vehicle-mounted lens antenna of the present invention has a structure in which a resin-made dielectric lens such as polypropylene is integrally formed with a vehicle bumper by injection molding or the like. Therefore, the manufacturing cost and mounting work of the antenna can be substantially simplified to the cost and mounting work of only the primary radiator, and the manufacturing cost and the mounting cost to the vehicle are extremely low.

The vehicle-mounted lens antenna of the present invention is
Since the dielectric lens, which occupies a major part in terms of electrical performance, is constructed integrally with the mechanically strong vehicle bumper,
Performance is maintained even under adverse vehicle environment such as high level vibration, wide temperature range, dust, wind and rain.

[Brief description of drawings]

FIG. 1 is an exploded perspective view (A) of a vehicle-mounted lens antenna according to an embodiment of the present invention and a cross-sectional view (B) showing an assembled state of the vehicle antenna.

FIG. 2 is a perspective view showing an external appearance of a portion excluding a primary radiator of a vehicle-mounted lens antenna according to another embodiment of the present invention.

[Explanation of symbols]

 10 Vehicle bumper 11 Dielectric lens 12 Stay (holding mechanism) 13 Primary radiator (planar antenna) 14 Dielectric substrate 15,16 Coaxial connector 17 Coaxial cable

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Claims (5)

[Claims] 1. A dielectric lens made of the same material as a vehicle bumper made of resin and protruding from the rear surface of the vehicle bumper, and a primary radiator arranged near the focal point of the dielectric lens. An in-vehicle lens antenna, which is characterized in that 2. The primary radiator according to claim 1, wherein the primary radiator is made of the same material as that of the vehicle bumper and is held by a holding mechanism protruding from a back surface of the vehicle bumper at a peripheral portion of the dielectric lens. An in-vehicle lens antenna, which is characterized in that 3. The vehicle-mounted lens antenna according to claim 2, wherein the vehicle bumper, the dielectric lens and the holding mechanism are integrally manufactured by injection molding. 4. The vehicle-mounted lens antenna according to claim 1, wherein the primary radiator is a planar antenna formed on a dielectric substrate. 5. The vehicle-mounted lens antenna according to claim 1, wherein the resin that is a material of the vehicle bumper is polypropylene.