JPH04337907A - Antenna - Google Patents

Abstract

PURPOSE:To manufacture the thinned antenna and to reduce the number of parts. CONSTITUTION:An antenna element 3 is fixed to the inner face of a housing 1. A flexible printed wiring board 6 forming a ground 4 and a microstrip line 5 with metal foil is joined onto the surface of a dielectric plate 7. The dielectric plate 7 is arranged in the housing 1, the terminal edge part of the dielectric plate 7 is fitted and fixed to the opening part 2 of the housing 1, and the antenna element 3 and the microstrip line 5 are electrically connected. Connection to an amplifier or the like can be executed by extending the terminal edge part of the flexible printed wiring board 6 and pulling out the microstrip line 5 and the ground 4, and it is not necessary to use a coaxial cable while directly connecting it to the antenna. By fitting the terminal edge part of the dielectric plate 7 to the opening part 2 of the housing 1, it can be also used as the cover of the housing 1.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin antenna that is installed on a moving object such as an automobile.

0002

2. Description of the Related Art Conventional thin antennas are often constructed using printed wiring boards. That is,
After creating a laminate 12 in which metal foils 11 such as copper foil are laminated on both sides through the process of lamination molding, each metal foil 11 is etched to form a pattern, as shown in FIG. 4(a).
), an antenna block A was created in which an antenna element 3 was formed using one metal foil 11, and a ground 4 with a loophole 13 was formed using the other metal foil 11, and a through hole was further formed at the loophole 13. The current collecting pin 14 is inserted and attached by processing, and the current collecting pin 14 is connected to the antenna element 3 by soldering or the like. In the antenna block A made of a printed wiring board in which the antenna element 3 and the ground 4 are provided in this manner, a dielectric layer is formed by the laminated plate 12. Then, the coaxial cable 15 is attached to the bottom surface of the antenna block A, and the inner conductor 15a of the coaxial cable 15 is connected to the current collecting pin 14 by soldering or the like, and the outer conductor 15b of the coaxial cable 15 is connected to the ground 4 by soldering or the like. The antenna is constructed by attaching this antenna block A inside the housing 1 with screws or the like as shown in FIG. 4(b), and further fitting the cover plate 16 into the opening 2 of the housing 1 and attaching it with screws or the like. It is something that can be done.

0003

[Problems to be Solved by the Invention] However, in the antenna configured as described above, the antenna block A incorporated in the housing 1 is connected to an amplifier etc. by connecting a coaxial cable 15 to the bottom surface of the antenna block A. Since the diameter of the coaxial cable 15 is added to the total thickness of the antenna, there is a problem in that there is a limit to how thin the antenna can be made.

The present invention has been made in view of the above points, and it is an object of the present invention to provide an antenna that can be manufactured in a thinner form and that can also reduce the number of parts. be.

[0005]

[Means for Solving the Problems] In the antenna according to the present invention, an antenna element 3 is fixed to the inner surface facing the opening 2 of a housing 1 having one side open, and the antenna element 3 is electrically connected to the ground 4 using metal foil. A flexible printed wiring board 6 on which an insulated microstrip line 5 is formed is integrally bonded to one surface of a dielectric plate 7, and the housing 1 is assembled so that the other surface of the dielectric plate 7 faces the antenna element 3. The antenna element 3 and the microstrip line 5 are electrically connected to each other by fitting and fixing the edge of the dielectric plate 7 into the opening 2 of the housing 1. be.

[0006]

[Function] A flexible printed wiring board 6 on which a ground 4 and a microstrip line 5 electrically insulated from the ground 4 are formed with metal foil is integrally bonded to one surface of a dielectric board 7, and the antenna element 3 and the micro Since the microstrip line 5 is electrically connected to the strip line 5, the connection to the amplifier etc. is made by extending the edge of the flexible printed wiring board 6 and drawing out the ground 4 and the microstrip line 5. This eliminates the need to use the coaxial cable 15 when connecting to an amplifier or the like. Furthermore, since the edge of the dielectric plate 7 is fitted and fixed into the opening 2 of the housing 1, the dielectric plate 7 can also serve as the lid of the housing 1, reducing the number of parts. can.

[0007]

EXAMPLES The present invention will be explained in detail by way of examples. The housing 1 is made of a resin molded product and has an opening 2 on one side (bottom side).
It is formed into a box shape with a Further, the antenna element 3 is formed of a metal plate such as a copper plate with a thickness of about 0.1 to 0.5 mm, and a current collecting pin 14 is attached to the lower surface of the metal plate forming the antenna element 3, one end of which is soldered. It is attached by attaching it etc. This antenna element 3
As shown in FIG. 1(a), the antenna element 3 is attached to the inner surface facing the opening 2 of the housing 1, and the antenna element 3 is attached so that the surface of the antenna element 3 and the inner surface of the housing 1 are flush with each other. When attaching the antenna element 3, even if a recess is provided on the inner surface of the housing 1 and the antenna element 3 is fitted into the recess,
Furthermore, when the housing 1 is resin-molded, the antenna element 3 may be insert-molded into the housing 1 and attached integrally.

On the other hand, the dielectric plate 7 is made of a resin material having a small dielectric constant (ε) or dielectric loss tangent (tan δ), such as polypropylene (tan δ = 0.0005), polyphenylene oxide (PPO; tan δ = 0.0004), or polyethylene terephthalate. (PET; tanδ=0.0004)
, polymethylpentene (tan δ = 0.00007),
It is made by injection molding etc. of fluororesin (tan δ = 0.0002), and the dielectric plate 7
An engaging convex step 23 is provided protruding from each edge of the four circumferences at a position near one surface side of the holder. The size of the engaging convex portion 23 of the dielectric plate 5 is formed to be approximately equal to the size of the opening 2 of the housing 1. Further, on one surface of the dielectric plate 7, a flexible printed wiring board 6 is laminated and integrally joined as shown in FIG. 2(a).

The flexible printed wiring board 6 uses a flexible laminate in which a metal foil 11 such as copper foil is adhered to the surface of an insulating film 17 such as a polyimide film, and a part of the metal foil 11 is etched. By removing the insulating space 18 as shown in FIGS. 2(c) and 2(d), the microstrip line 5 is formed as shown in FIG. 2(b), and the other part of the metal foil 11 is used as the ground 4. It is created by forming
Land 19 provided at one end of microstrip line 5
A through hole 19 passing through the dielectric board 7 and the flexible printed wiring board 6 is drilled at the center of the board. Further, a part of the flexible printed wiring board 6 is extended as a lead part 21 from one end edge of the flexible printed wiring board 6, and the microstrip line 5 is formed so as to reach the tip of this lead part 21. Also, a part of the ground 4 is extended to the lead part 21 as a terminal part 22.

Dielectric plate 7 formed as described above
is arranged in the housing 1, the current collecting pin 14 is inserted into the through hole 20, the dielectric plate 7 is brought into close contact with the antenna element 3, and the engaging step 23 is fitted into the opening 2 of the housing 1. The dielectric plate 7 is attached to the housing 1 by fixing with screws, adhesive, high-frequency welding, or the like. In order to seal the inside of the housing 1, a packing 24 such as an O-ring may be attached between the opening 2 of the housing 1 and the engaging convex step 23 of the dielectric plate 7. Furthermore, current collector pin 1
4 and the land 19 of the microstrip line 5 by soldering or the like, the antenna element 3 is electrically connected to the microstrip line 5 via the current collecting pin 14, and the antenna as shown in FIG. Can be assembled. In an antenna assembled in this way,
Since a part of the flexible printed wiring board 6 can be extended as a lead part 21, this lead part 21
By connecting the microstrip line 5 to the amplifier at the part shown in FIG. This prevents the antenna from becoming thicker due to the addition of a diameter. For example, by connecting to the lead part 21 using a strip-shaped flexible printed wiring board having the same structure as the lead part 21, the microstrip line 5 can be extended as an amplifier circuit, and the terminal part 22 of the ground 4 can be extended to connect to the amplifier. It is also possible to connect the coaxial cable 15 to the tip of the lead portion 21. Note that by using a two- or three-layer stack of metal foils 11 as the flexible printed wiring board 6 to be bonded to the dielectric board 7, the bottom layer of the metal foil 11 is provided with microstrip lines as described above. 5 and the ground 4, and the metal foil 11 of another layer can form the ground 4 and the shield layer.

Furthermore, in the antenna assembled in this way, if a dielectric plate 7 forming a dielectric layer between the antenna element 3 and the ground 4 is made of a resin having a small dielectric constant and dielectric loss tangent, The antenna can be made thinner by forming the dielectric plate 7 thinner. Further, as shown in FIG. 3, the dielectric plate 7 may be formed into a plurality of layers 7a and 7b made of different materials such as resins with different dielectric constants and dielectric loss tangents, and the thickness of each layer 7a and 7b may be changed. Accordingly, the distribution of the dielectric constant and dielectric loss tangent at each portion of the dielectric plate 7 can be changed. Therefore, by using such a dielectric plate 7, the antenna element 3
The distribution of the dielectric constant and dielectric loss tangent between the ground 4 and ground 4 can be adjusted in various ways. By adjusting it, it is possible to receive reception over a wide band of frequencies. Further, by adjusting the thickness of the dielectric plate 7, reception in a wide band of frequencies can be similarly made possible.

0012

Effects of the Invention As described above, the present invention fixes an antenna element to the inner surface facing the opening of a housing that is open on one side, and forms a ground and a microstrip line electrically insulated from the ground using metal foil. The flexible printed wiring board is integrally bonded to one surface of the dielectric plate, and the dielectric plate is placed in the housing with the other surface facing the antenna element, and the edge of the dielectric plate is The antenna element and the microstrip line are electrically connected by fitting into the opening of the housing, and the microstrip line is electrically connected to the antenna element by extending the edge of the flexible printed wiring board to connect to the amplifier, etc. This can be done by pulling out the microstrip line and ground, which eliminates the need to connect the coaxial cable directly to the antenna, and the diameter of the coaxial cable does not add to the thickness of the antenna. can be made even thinner,
In addition, by fitting the edge of the dielectric plate into the opening of the housing, it can also be used as the lid of the housing.
This allows the number of parts to be reduced.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the present invention, in which (a) is a cross-sectional view and (b) is a bottom view.

FIG. 2 shows a dielectric board and a flexible printed wiring board used in the present invention, where (a) is a cross-sectional view, (b) is a bottom view, and (c) is a line A--I in FIG. 2(b). Enlarged cross-sectional view, (
d) is an enlarged sectional view of the flexible printed wiring board along the Ro-Ro line in FIG. 2(b).

FIG. 3 is a cross-sectional view of a dielectric plate and a flexible printed wiring board used in the present invention.

FIG. 4 shows a conventional example, in which (a) is a cross-sectional view of an antenna block, and (b) is a cross-sectional view of the antenna.

[Explanation of symbols]

1 Housing 2 Opening 3 Antenna element 4 Grand 5 Microstrip line 6 Flexible printed wiring board 7 Dielectric plate

Claims (1)

[Claims] Claim 1: An antenna element is fixed to the inner surface facing the opening of a housing that is open on one side, and a flexible printed wiring board is formed with a metal foil to form a ground and a microstrip line electrically insulated from the ground. The dielectric plate is integrally joined to one surface of the plate, and the dielectric plate is arranged in the housing with the other surface facing the antenna element, and the edge of the dielectric plate is fitted and fixed into the opening of the housing. An antenna characterized by electrically connecting an antenna element and a microstrip line.