JP4629928B2 - Antenna unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an antenna unit in which a coaxial cable is connected to a chip-type antenna element.
[0002]
[Past Technology]
The present inventor first designed an in-vehicle antenna unit used in ETC or the like as shown in FIG. In the figure, 10 is a circular metal base plate, 12 is an antenna element mounted on the surface of the metal base plate 10, and 14 is a coaxial cable fixed to the back side of the metal base plate 10. A resin radome is placed on the surface side of the metal base plate 10 but is not shown.
[0003]
The antenna element 12 includes a dielectric substrate 16, a radiating conductor 18 provided on the front surface, a ground conductor 20 provided on the back surface, and a feed pin 22. One end of the power feed pin 22 is electrically connected to the radiation conductor pattern 18, passes through the dielectric substrate 16 and the ground conductor 20, and the other end protrudes from the surface on the ground conductor 20 side. The antenna element 12 is mounted on the metal base plate 10 such that the feed pin 22 passes through the hole 24 of the metal base plate 10 and protrudes from the back surface of the metal base plate 10.
[0004]
A cable fixing portion 26 for fixing the end portion of the coaxial cable 14 is formed on the back surface of the metal base plate 10. The cable fixing portion 26 folds a metal plate extending from a part of the periphery of the metal base plate 10 to the back surface of the metal base plate 10, cuts and raises both sides of the metal plate, and the first caulking piece 28 and the second caulking piece 28 A caulking piece 30 is formed. When fixing the end portion of the coaxial cable 14 to the cable fixing portion 26, the end portion of the stripped coaxial cable 14 is set as illustrated, and the first caulking piece 28 is used for the sheath 32 of the coaxial cable 14. The portion is caulked from both sides, and the second caulking piece 30 caulks the portion of the outer conductor 34 of the coaxial cable 14 from both sides. After fixing the coaxial cable 14 to the back side of the metal base plate 10 in this way, the central conductor 36 of the coaxial cable 14 and the feed pin 22 of the antenna element 12 are directly connected by soldering.
[0005]
[Problems to be solved by the invention]
The antenna unit is configured such that the coaxial cable 14 is placed on the metal plate folded back on the back surface of the metal base plate 10, and when the coaxial cable 14 is caulked with the caulking pieces 28 and 30, the coaxial cable 14 Since the cross section of the wire is deformed into an ellipse that is long in the direction perpendicular to the metal base plate 10 (hereinafter sometimes referred to as the vertical direction), the dimension in the direction perpendicular to the metal base plate 10 is increased and the antenna unit is made thinner. There were restrictions. Further, since the coaxial cable is deformed into an ellipse, and the caulking pieces on both sides of the coaxial cable are difficult to caulk uniformly, the position of the coaxial cable in the left-right direction is not stable, and thus electrical characteristics tend to vary.
[0006]
An object of the present invention is to provide an antenna unit capable of making the antenna unit thinner and capable of stabilizing electrical characteristics.
[0007]
[Means for Solving the Problems]
In order to achieve this object, the present invention mounts an antenna element on the surface of a metal base plate, projects a feeding pin of the antenna element to the back surface of the metal base plate, and connects a cable fixing portion to the back surface of the metal base plate. In the antenna unit, the end of the coaxial cable is fixed thereto, and the feeding pin of the antenna element and the central conductor of the coaxial cable are directly connected to the back side of the metal base plate. The metal plate extending from a part of the periphery of the metal base plate is bent into a U-shape on the back side of the metal base plate, and the rising wall portion rising from the part of the periphery of the metal base plate by the outer diameter of the coaxial cable; A ceiling portion extending in the direction parallel to the metal base plate from the tip of the rising wall portion, and the outer diameter of the coaxial cable from the tip of the ceiling portion to the metal base plate Forming a falling wall portion that only falls, and forming a notch portion for inserting a coaxial cable in the rising wall portion and the falling wall portion, and inserting a coaxial cable into the notch portion, By restricting lateral movement of the coaxial cable at the edges on both sides of the notch, and restricting movement in the direction perpendicular to the metallic base plate of the coaxial cable at the ceiling, the coaxial cable is connected to the back surface of the metallic base plate. It is characterized by being fixed to.
[0008]
In this way, the coaxial cable is sandwiched between the ceiling portion of the cable fixing portion and the metal base plate so that the position in the vertical direction is restricted, and there is little risk of being deformed into a long oval shape in the vertical direction. The dimension in the vertical direction can be reduced, and the antenna unit can be thinned. Further, the variation in the deformation amount of the coaxial cable can be suppressed and the position can be stabilized, so that the variation in electrical characteristics can be reduced.
[0009]
The antenna unit of the present invention has a configuration in which a protruding piece extending along the back surface of the metal base plate is formed at the tip of the falling wall portion, and the protruding piece is fixed to the metal base plate by soldering or bonding. preferable.
[0010]
If it does in this way, it will become easy to fix the tip side of a falling wall part to a metal base board, and fixation of a coaxial cable can be performed more certainly.
[0011]
In the antenna unit of the present invention, the metal base plate is circular, the rising wall portion is flat, the intermediate portion in the width direction is connected to the metal base plate, and both end portions in the width direction are separated from the periphery of the metal base plate. It is preferable that both end portions of the rising wall portion are inserted and fixed in grooves formed in a radome that covers the antenna element and the metal base plate.
[0012]
With such a configuration, the metal base plate can be firmly fixed to the radome, and the positional accuracy of the metal base plate is improved.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0014]
Embodiment 1 FIG. 1 shows an embodiment of the present invention. In the figure, the same parts as those of the antenna unit of FIG. 4 described above are denoted by the same reference numerals. That is, 10 is a circular metal base plate, 12 is an antenna element, 14 is a coaxial cable, 16 is a dielectric substrate of the antenna element 12, 18 is a radiation conductor, 20 is a ground conductor, and 22 is a feed pin. The antenna element 12 is mounted on the metal base plate 10 such that the feed pin 22 passes through the hole 24 of the metal base plate 10 and protrudes from the back surface of the metal base plate 10.
[0015]
The feature of this antenna unit is that a cable fixing portion 26 formed by bending a metal plate extending from a part of the periphery of the metal base plate 10 into a U-shape is provided on the back side of the metal base plate 10. is there. That is, the cable fixing portion 26 rises from a part of the periphery of the metal base plate 10 by the outer diameter of the coaxial cable 14, and extends from the tip of the rise wall portion 38 in a direction parallel to the metal base plate 10. The ceiling portion 40 has a falling wall portion 42 that falls from the tip of the ceiling portion 40 toward the metal base plate 10 by the outer diameter of the coaxial cable 14. In addition, a notch 44 for inserting a coaxial cable is formed in the intermediate portion in the lateral direction of the rising wall 38 and the falling wall 42. Further, a pair of projecting pieces 46 extending in the direction of the coaxial cable along the back surface of the metal base plate 10 is formed at the tip of the falling wall portion 42.
[0016]
When the coaxial cable 14 is fixed by the cable fixing portion 36, the end portion of the coaxial cable 14 is inserted into the cutout portion 44, and the portion of the sheath 32 of the coaxial cable 14 is pressed against the metal base plate 10 by the ceiling portion 40. In both cases, the protruding piece 46 is fixed to the metal base plate 10 by soldering or an adhesive in a state where the lateral movement of the coaxial cable 14 is prevented at both edges of the notch 44. Further, the outer conductor 34 of the coaxial cable 14 is soldered to the metal base plate 10, and the center conductor 36 is soldered to the feed pin 22 of the antenna element 12.
[0017]
With such a fixing structure, the coaxial cable 14 is directly pressed against the back surface of the metal base plate 10 and is less likely to be deformed into an elliptical shape that is long in the vertical direction, and the dimension in the direction perpendicular to the metal base plate 10 can be reduced. The antenna unit can be made thinner. Even if the coaxial cable 14 is deformed in the lateral direction, variations between individual products can be reduced and the position can be stabilized, so that variations in electrical characteristics can be reduced.
[0018]
Embodiment 2 FIG. 2 shows another embodiment of the present invention. In this embodiment, a resin radome 48 is put on the antenna unit of FIG. Inside the radome 48 are a deepest recess 50 in which the antenna element 12 is housed, a circular recess 52 in which the metal base plate 10 is fitted, and a shallow rectangular recess 54 in which the bottom plate 56 of the radome 48 is fitted. It is formed in three stages. Further, a notch 58 is formed in a portion where the coaxial cable 14 is inserted, and portions corresponding to the bottom of the rectangular recess 54 (flat portions of the edge of the circular recess 52) on both sides of the notch 58 are formed. A groove 60 into which both end portions of the rising wall portion 38 are inserted is formed.
[0019]
As shown in FIG. 1E, the metal base plate 10 has a circular shape, and the rising wall portion 38 rising from a part of the periphery of the metal base plate 10 has a flat plate shape. Therefore, the rising wall portion 38 is a metal base at the intermediate portion in the width direction. Although connected to the plate 10, both ends in the width direction are separated from the periphery of the metal base plate 10. The both end portions of the rising wall portion 38 are inserted into the groove 60 formed in the radome 48 when the metal base plate 10 is fitted into the circular recess 52 of the radome 48. In this way, the metal base plate 10 can be firmly fixed to the radome 40, and the position fixing accuracy of the metal base plate 10 can be improved.
[0020]
Embodiment 3 FIG. 3 shows still another embodiment of the present invention. FIG. 3 shows a state before the coaxial cable is attached. The antenna unit is different from the antenna unit of FIG. 1 in that 1) a pair of holding pieces 62 are formed on the ceiling portion 40 of the cable fixing portion 26, and the antenna unit is coaxial. After inserting the cable through the notch 44, both sides of the coaxial cable are held by the holding piece 62, and 2) the folded piece 64 inside the pair of protruding pieces 46 extending from the tip of the falling wall part 42. The folded piece 64 is brought into contact with the outer conductor of the coaxial cable. When the pressing piece 62 and the folded piece 64 are formed as described above, the positioning accuracy and fixing strength of the coaxial cable are improved, and variations in electrical characteristics can be reduced, and the tensile strength of the coaxial cable can be improved. Since the configuration other than the above is the same as that of the first embodiment, the same portions are denoted by the same reference numerals and description thereof is omitted.
[0021]
【The invention's effect】
As described above, according to the present invention, the coaxial cable is directly pressed against the back surface of the metal base plate, and the coaxial cable is less likely to be deformed into an elliptical shape that is long in the vertical direction, while reducing variation in the lateral deformation amount, The dimension in the direction perpendicular to the metal base plate can be reduced, and the antenna unit can be made thinner. Further, the variation in the amount of deformation of the coaxial cable is small and the position is stable, so that the variation in electrical characteristics can be reduced.
[Brief description of the drawings]
FIG. 1 shows an embodiment of an antenna unit according to the present invention, (A) is a front view, (B) is a side view, (C) is a rear view, (D) is a plan view, and (E) is a front view. A side perspective view and (F) are back side perspective views.
2A and 2B show another embodiment of the antenna unit according to the present invention. FIG. 2A is a front view, FIG. 2B is a rear view, FIG. 2C is a cross-sectional view taken along the line CC of FIG. (E) is a front perspective view, (F) is a rear perspective view.
FIG. 3 shows still another embodiment of the antenna unit according to the present invention, (A) is a front view, (B) is a side view, (C) is a rear view, (D) is a plan view, and (E). Is a front perspective view, (F) is a rear upper perspective view, and (G) is a rear lower perspective view.
4A is a front view, FIG. 4B is a side view, FIG. 4C is a rear view, FIG. 4D is a plan view, and FIG. 4E is a front perspective view. ) Is a rear perspective view.
[Explanation of symbols]
10: Metal base plate
12: Antenna element
14: Coaxial cable
16: Dielectric substrate
18: Radiation conductor
20: Ground conductor
22: Power supply pin
26: Cable fixing part
36: Center conductor
38: Rising wall
40: Ceiling
42: Falling wall
44: Notch
46: Projection
48: Radome
60: Groove

Claims (3)

The antenna element (12) is mounted on the surface of the metal base plate (10), and the feeding pin (22) of the antenna element is protruded from the back surface of the metal base plate (10), so that the metal base plate (10) A cable fixing portion (26) is provided on the back surface, and the end portion of the coaxial cable (14) is fixed thereto, and the feeding pin (22) of the antenna element (12) on the back surface side of the metal base plate (10) In the antenna unit that is directly connected to the central conductor (36) of the coaxial cable (14),
The cable fixing portion (26) is formed by bending a metal plate extending from a part of the periphery of the metal base plate (10) into a U-shape on the back side of the metal base plate and A rising wall (38) rising by the outer diameter of the coaxial cable, a ceiling (40) extending in parallel to the metal base plate (10) from the tip of the rising wall, and a metal base plate from the tip of the ceiling And forming a falling wall portion (42) falling toward the outer diameter of the coaxial cable toward (10) and cutting the coaxial cable into the rising wall portion (38) and the falling wall portion (42). It consists of what formed the notch (44),
The coaxial cable (14) is inserted into the notch (44), and the lateral movement of the coaxial cable (14) is restricted at both edges of the notch (44), and the ceiling (40) The antenna unit is characterized in that the coaxial cable (14) is fixed to the back surface of the metal base plate (10) by restricting the movement of the coaxial cable (14) in the direction perpendicular to the metal base plate (10). A protruding piece (46) extending along the back surface of the metal base plate (10) is formed at the tip of the falling wall (42), and the protruding piece (46) is soldered or bonded to the metal base plate (10). The antenna unit according to claim 1, wherein the antenna unit is fixed. The metal base plate (10) has a circular shape, the rising wall portion (38) has a flat plate shape, the intermediate portion in the width direction is connected to the metal base plate (10), and both end portions in the width direction of the metal base plate (10). It is separated from the periphery, and both end portions of the rising wall portion (38) are inserted and fixed in grooves (60) formed in the radome (48) covering the antenna element and the metal base plate. The antenna unit according to claim 1.

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