Antenna apparatus

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the appended drawings which given by way of illustration only, and thus are not intended as a definition of the limits of the present invention, and wherein;

FIG. 1 is a schematic sectional view showing the configuration of an antenna apparatus according to the present embodiment;

FIG. 2 is a perspective view showing a shield cover, a coaxial cable, and the like, in the state in which the antenna apparatus shown in FIG. 1 is turned upside down;

FIG. 3 is a schematic view illustrating an angle between the base of the tongue flap of the shield cover and a connecting piece;

FIG. 4 is an enlarged view showing a soldering structure of the tongue flap of the shield cover and the outer conductor of the coaxial cable according to the present embodiment;

FIG. 5 is an enlarged view showing a modification of the soldering structure of the tongue flap to the outer conductor;

FIG. 6 is an enlarged view showing another modification of the soldering structure of the tongue flap to the outer conductor;

FIG. 7 is a schematic sectional view showing the configuration of a conventional antenna apparatus;

FIG. 8 is a perspective view showing a shield cover, a coaxial cable, and the like, in the state in which the antenna apparatus shown in FIG. 7 is turned upside down; and

FIG. 9 is a schematic sectional view for illustrating a rise of the shield cover owing to a rise of solder.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, the preferred embodiment of an antenna apparatus according to the present invention will be described with reference to the attached drawings.

An antenna apparatus 1 according to the present embodiment includes an antenna element 2, a circuit substrate 3, a shield cover 4, a coaxial cable 5, and the like, as shown in FIGS. 1 and 2. Incidentally, FIG. 2 and FIGS. 3-6, which will be described later, show the state of the shield cover 4, the coaxial cable 5, and the like, in which the antenna apparatus 1 shown in FIG. 1 is turned upside down. Moreover, the showing of the soldering of a tongue flap 4b of the shield cover 4 to an outer conductor 5b of the coaxial cable 5, which will be described later, is omitted.

The antenna element 2 is made of a ceramic to be formed in a plate being slightly thick in the present embodiment. A patch type receiving surface 6 as a receiving unit receiving electric waves is stuck on a surface of the antenna element 2 on one side. Incidentally, the receiving surface 6 of the antenna element 2 is drawn to be thicker than the actual thickness thereof in FIG. 1. Moreover, a not shown GND pattern shaped in a metallic thin film is stuck on almost the whole surface of the antenna element 2 on the opposite side to the receiving surface 6 except for an input pin 7 and the circumjacent part thereof.

The circuit substrate 3 is provided on the opposite surface side of the antenna element 2 to the receiving surface 6. A not shown GND pattern shaped in a metallic thin film is stuck on almost the whole surface of the circuit substrate 3 on the side of the antenna element 2 except for the input pin 7 and the circumjacent part thereof separately from the GND pattern of the antenna element 2.

In the present embodiment, the GND pattern of the circuit substrate 3 and the GND pattern of the antenna element 2 are stuck together with an adhesive member, such as a double-coated adhesive tape, and the antenna element 2 and the circuit substrate 3 are thereby bonded together. Moreover, the GND pattern of the circuit substrate 3 functions as the GND pattern of the antenna element 2 together with the GND pattern of the antenna element 2 itself.

A not shown circuit amplifying an input from the antenna element 2 to output the amplified input is formed on the surface of the circuit substrate 3 on the opposite side to the antenna element 2, i.e., a circuit surface 3a. A not shown plurality of through-holes is formed in the circuit substrate 3 at suitable positions, and the GND of the circuit on the circuit surface 3a is connected to the GND pattern on the back surface of the circuit substrate 3 through the through-holes.

The input pin 7 penetrates through the receiving surface 6 of the antenna element 2 and the circuit surface 3a of the circuit substrate 3 perpendicularly to them at a predetermined position of the antenna element 2 and the circuit substrate 3. In the present embodiment, the input pin 7 is electrically connected to the receiving surface 6 and the circuit by soldering, and the input pin 7 inputs an electric wave signal received by the receiving surface 6 of the antenna element 2 to the circuit of the circuit substrate 3.

The shield cover 4, which is made of a metal and formed in substantially a box, is attached to the circuit substrate 3 on the side of the circuit surface 3a so as to cover the circuit surface 3a, and the shield cover 4 shields the circuit surface 3a from disturbing waves arriving at the circuit surface 3a from the outside. Moreover, a base surface 4a of the substantially box-like shield cover 4 is arranged in parallel to the receiving surface 6 of the antenna element 2 and the circuit surface 3a of the circuit substrate 3.

As shown in the sectional view of FIG. 1, a part of the shield cover 4 is formed as a projection to penetrate the circuit substrate 3, and thereby the shield cover 4 is located to the circuit substrate 3. Moreover, as shown in FIG. 2, in the present embodiment, the shield cover 4 is electrically connected to the GND of the circuit by being soldered to the GND on the circuit surface 3a of the circuit substrate 3.

In the inside of the shield cover 4, the coaxial cable 5 is inserted. The core wire 5a of the coaxial cable 5 is electrically connected to the circuit on the circuit surface 3a of the circuit substrate 3 by soldering. Driving power is supplied to the circuit through the core wire 5a, and a signal received with the antenna element 2 and amplified by the circuit is output from the circuit through the core wire 5a.

Moreover, the tongue flap 4b is formed on the shield cover 4 so as to be bent from the base surface 4a of the shield cover 4 to extend to the coaxial cable 5.

In the present embodiment, the tongue flap 4b is bent at a position between the bent portion from the base surface 4a of the shield cover 4 and the end on the coaxial cable side, and the tongue flap 4b includes a tabular base 4c formed by being bent from the base surface 4a of the shield cover 4 toward the coaxial cable 5 at almost a right angle and a tabular connecting piece 4d formed by the bending of the end of the tongue flap 4b on the coaxial cable side.

In the terminal portion of the connecting piece 4d, an arcuate notch along the outer conductor 5b of the coaxial cable 5 is formed, and the connecting piece 4d and the outer conductor 5b of the coaxial cable 5 are electrically connected to each other by soldering in the state in which the notch portion comes close to or abuts on the outer conductor 5b.

In the present embodiment, if the angle formed by the base 4c of the tongue flap 4b and the connecting piece 4d is denoted by θ as shown in FIG. 3, then the connecting piece 4d is bent at a bent portion R to the base 4c toward the outside of the shield cover 4 so that the angle θ may within the range:

0°<θ≦90° (1).

Moreover, in the present embodiment, as shown in FIG. 4, the surface on the opposite side to the surface opposed to the coaxial cable 5 between the front/back surfaces of the tabular connecting piece 4d and the outer conductor 5a of the coaxial cable 5 are electrically connected to each other by the soldering using the solder H.

Incidentally, although the state in which the connecting piece 4d of the tongue flap 4b is soldered only to a part of the outer conductor 5b is schematically shown in FIG. 4 and FIGS. 5 and 6, both will be described later, the tongue flap 4b and the outer conductor 5b of the coaxial cable 5 are actually soldered together by infiltrating the solder H into almost the whole area in the circumferential direction of the outer conductor 5b.

The GND potential is supplied to the outer conductor 5b of the coaxial cable 5, and the GND potential is supplied from the outer conductor 5b of the coaxial cable 5 to the circuit of the circuit substrate 3 through the tongue flap 4b and the shield cover 4 by the connection of them by the soldering.

Moreover, in the present embodiment, as shown in FIG. 1, the antenna apparatus 1 is provided with a bottom cover 8 made of a metal on the outside of the base surface 4a of the shield cover 4, and the further improvement of the grounding efficiency of the circuit is achieved by bringing the base surface 4a of the shield cover 4 and the bottom cover 8 into surface contact.

Next, the operation of the antenna apparatus 1 according to the present embodiment will be described.

Driving power is supplied to the circuit on the circuit substrate 3 of the antenna apparatus 1 through the core wire 5a of the coaxial cable 5. When the receiving surface 6 of the antenna element 2 receives a high frequency electric wave for the GPS or for a satellite radio, the electric wave signal is transmitted to the circuit on the circuit substrate 3 through the input pin 7, and an electric wave signal amplified by the circuit is output through the core wire 5a of the coaxial cable 5.

The circuit of the circuit substrate 3 is shielded from disturbing waves from the outside by the shield cover 4 made of a metal, which caver 4 covers the circuit. Moreover, the GND of the circuit is connected to the shield cover 4, as described above, and the circuit is grounded by receiving the supply of the GND potential from the outer conductor 5b of the coaxial cable 5 to the shield cover 4. The GND potential is also supplied to the GND pattern of the circuit substrate 3 through the through-holes of the circuit substrate 3, and the GND pattern of the circuit substrate 3 is grounded, so that the GND level is provided to the antenna element 2.

At that time, the surface on the opposite side to the surface opposed to the coaxial cable 5 between surfaces of the tabular connecting piece 4d formed at the end on the coaxial cable side of the tongue flap 4b of the shield cover 4 and the outer conductor 5a of the coaxial cable 5 are soldered together, and the tongue flap 4b and the outer conductor 5b of the coaxial cable 5 are connected to each other by being soldered together so as to infiltrate the solder H over almost the whole area in the circumferential direction of the outer conductor 5b. In this way, the contact area of the tongue flap 4b and the outer conductor 5b is more enlarged, and thereby the grounding efficiency of the shield cover 4 through the tongue flap 4b is improved.

Moreover, in the soldering, the melted solder H infiltrates the outer conductor 5a and diffuses onto the connecting piece 4d by the surface tension of the melted solder H. Because the connecting piece 4d (bent portion) is formed by being bent to the base 4c of the tongue flap 4b, the surface tension of the melted solder H is intercepted at the bent portion R between the base 4c of the tongue flap 4b and the connecting piece 4d. Consequently, the spreading of the melted solder H into the direction of the base 4c of the tongue flap 4b is effectively obstructed, and it is prevented that the melted solder H spreads on the surface of the base 4c to rise higher than the height of the base surface 4a of the shield cover 4.

In this case, even if ordinary soldering operation is performed at the time of soldering, the diffusion of the melted solder H on the connecting piece 4d (bent portion) surely stops at the bent portion R. Consequently, it is unnecessary to perform the soldering especially carefully or to perform the soldering using an especial technique, and the diffusion of the melted solder H onto the base 4c of the tongue flap 4b can be sufficiently obstructed by the ordinary soldering operation to surely prevent the rise of the solder H.

Incidentally, by providing the bottom cover 8 made of a metal to the bottom of the antenna apparatus 1, and by bringing the base surface 4a of the shield cover 4 and the bottom cover 8 into surface contact to ground the shield cover 4 like the present embodiment, the grounding efficiency of the circuit is more improved.

As described above, by the antenna apparatus 1 according to the present embodiment, the end of the tongue flap 4b of the shield cover 4 on the coaxial cable side is bent to form the connecting piece 4d, and the connecting piece 4d and the outer conductor 5b of the coaxial cable 5 are soldered together. Consequently, the surface tension of the melted solder H is intercepted at the bent portion R between the connecting piece 4d and the base 4c of the tongue flap 4b, and the diffusion of the melted solder H to the side of the base 4c is obstructed.

Hence, even if the ordinary soldering operation is performed, it is surely prevented that the solder H spreads on the surface of the base 4c of the tongue flap 4b to rise higher than the base surface 4a of the shield cover 4, and it becomes possible to surely connect shield cover 4 with the coaxial cable 5 through the tongue flap 4b by suitably soldering the connecting piece 4d to the outer conductor 5b.

Moreover, because the rise of the solder H in the connection portion between the tongue flap 4b and the outer conductor 5b of the coaxial cable 5 is not produced, it becomes possible to avoid the inclination of the shield cover owing to the rise from the bottom cover as shown in FIG. 9, and the normal directivity of the antenna can be obtained. The reception efficiency of electric waves is then stabilized, and it becomes possible to keep the assembly accuracy of the antenna apparatus 1.

Moreover, if grounding is performed by the surface contact between the base surface 4a of the shield cover 4 and the bottom cover 8 like the present embodiment, the grounding efficiency can be kept at a very high state. Moreover, because the soldering structure described above can be obtained by the ordinary soldering operation, the aforesaid advantages can be obtained without lowering the manufacturing efficiency of the antenna apparatus 1.

On the other hand, as described above, it is sufficient to bend the tongue flap 4b of the shield cover 4 only at one position between the bent portion from the base surface 4a of the shield cover 4 and the end of the tongue flap 4b on the coaxial cable side, and consequently the manufacturing process of the antenna apparatus 1 is not made to be complicated. Consequently, even if the tongue flap 4b is bent, the manufacturing efficiency of the antenna apparatus 1 is kept.

Moreover, if soldering is performed on the surface of the tabular connecting piece 4d on the opposite side to the surface thereof opposed to the coaxial cable 5 as shown in FIG. 4, the soldering can be performed from the upper side of the sheet of the drawing, and the soldering can be very easily performed.

Incidentally, the method of bending the connecting piece 4d of the tongue flap 4b and the surface on which the soldering of the connecting piece 4d is performed are not limited to those in the present embodiment.

For example, as shown in FIG. 5, it is also possible to connect the shield cover 4 with the coaxial cable 5 by greatly bending the connecting piece 4d to the base 4c of the tongue flap 4b toward the outside of the shield cover 4 so that the aforesaid angle θ may be within a range:

90°<θ≧180° (2),

and by soldering the surface opposed to the coaxial cable 5 between the front/back surfaces of the tabular connecting piece 4d to the outer conductor 5a of the coaxial cable 5.

If the soldering is performed like this, it becomes possible to suitably solder the connecting piece 4d to the outer conductor 5b to surely connect the shield cover 4 with the coaxial cable 5 through the tongue flap 4b, and similar advantages to those of the embodiment mentioned above can be obtained. Furthermore, the surface tension of the melted solder H is surely intercepted in the bent portion R between the connecting piece 4d and the base 4c of the tongue flap 4b to obstruct the spreading of the melted solder H to the side of the base 4c. Consequently, it becomes possible to surely prevent the solder H from rising higher than the height of the base surface 4a of the shield cover 4 by the connecting piece 4d (bent portion).

Moreover, for example, as shown in FIG. 6, it is also possible to solder the connecting piece 4d, the end of the tongue flap 4b on the coaxial cable side, to the outer conductor 5b of the coaxial cable 5 by forming the tongue flap 4b to be bent at a plurality of positions between the bent portion from the base surface 4a of the shield cover 4 and the end on the coaxial cable side.

If the soldering is performed like this, it becomes possible to surely connect the shield cover 4 with the coaxial cable 5 through the tongue flap 4b by suitably soldering the connecting piece 4d to the outer conductor 5b, and similar advantages to those of the embodiment mentioned above can be obtained. Furthermore, the surface tension of the melted solder H is surely intercepted at the bent portion R nearest to the side of the connecting piece 4d among the plurality of bent portions, and the spreading of the melted solder H to the side of the base 4c is obstructed. Consequently, it becomes possible to prevent the solder H from rising higher than the height of the base surface 4a of the shield cover 4.

Incidentally, although the description has been given to the antenna apparatus 1 including the patch type receiving surface 6 receiving the high frequency electric waves for the GPS or for a satellite radio on the surface of the antenna element 2 in the present embodiment and the aforesaid modifications, the antenna apparatus of the present invention is characterized by the structure of the tongue flap of the shield cover as described above, and the configuration of the antenna element is not limited to the one including the patch type receiving surface.

According to the embodiment of the present invention, an antenna apparatus comprises: an antenna element which includes a receiving unit to receive an electric wave; circuit substrate including a circuit surface on which a circuit is formed, the circuit amplifying an input from the antenna element; a shield cover covering the circuit surface to shield the circuit substrate from a disturbing wave, the shield cover being grounded; a coaxial cable to supply driving power and GND potential to the circuit on the circuit substrate, and to output a signal from the circuit, the coaxial cable being inserted into the shield cover, wherein the shield cover includes a base surface disposed in parallel with the circuit surface, and a tongue flap extending from the base surface to the coaxial cable, and the tongue flap includes a connecting piece which is formed by bending an end of the tongue flap at a side of the coaxial cable, the connecting piece being soldered to an outer conductor of the coaxial cable.

Thereby, the connecting piece is formed by bending the end of the tongue flap of the shield cover on the side of the coaxial cable, and the connecting piece and the outer conductor of the coaxial cable are soldered together. Consequently, the surface tension of melted solder is intercepted by a bent portion of the connecting piece. It is then prevented that the melted solder spreads along the tongue flap.

Consequently, even if the ordinary soldering operation is performed, it is surely prevented that the solder spreads on the surface of the tongue flap to rise higher than the height of the base surface of the shield cover, and it is also enabled that the connecting piece and the outer conductor are suitably soldered together to surely connect the shield cover with the coaxial cable through the tongue flap.

Moreover, because the rise of the solder in the connection portion between the tongue flap and the outer conductor of the coaxial cable does not appears, the inclination of the shield cover owing to the rise thereof from a bottom cover as shown in FIG. 9 can be avoided, and normal antenna directivity can be obtained. The reception efficiency of electric waves is then stabilized, and the assembly accuracy of the antenna apparatus can be kept.

Moreover, if grounding is performed by the surface contact of the base surface of the shield cover with the bottom cover, the grounding efficiency can be kept in a very high state. Moreover, because the soldering structure mentioned above can be obtained by the ordinary soldering operation, the above advantages can be obtained without lowering the manufacturing efficiency of the antenna apparatus.

It is preferable that the connecting piece is formed by bending the tongue flap at one position.

By doing so, in addition to the advantages of the first aspect mentioned above, it is sufficient to bend the tongue flap of the shield cover only at one position between the bent portion from the base surface of the shield cover and the end of the coaxial cable side, and the manufacturing processes of the antenna apparatus does not become complicated. Consequently, even if the tongue flap is bent, the manufacturing efficiency of the antenna apparatus can be kept.

It is preferable that the connecting piece is formed by bending the tongue flap at a plurality of positions.

By doing so, in addition to the advantages of the first aspect mentioned above, the surface tension of the melted solder is surely intercepted by a bent portion nearest to the connecting piece to prevent the melted solder from spreading along the tongue flap, and it can be surely prevented that the solder rises higher than the height of the base surface of the shield cover.

It is preferable that a surface on an opposite side to a surface opposed to the coaxial cable between front/back surfaces of the tabular connecting piece is soldered to the outer conductor of the coaxial cable.

By doing so, in addition to the advantages of each aspect mentioned above, the antenna apparatus is configured to solder the solder on the surface of the connecting piece on the opposite side to the surface of the connecting piece opposed to the coaxial cable. Thereby, it becomes possible to perform soldering easily and surely, and to keep productivity. Furthermore, the high grounding efficiency of the shield cover can be surely kept.

It is preferable that a surface opposed to the coaxial cable between front/back surfaces of the tabular connecting piece is soldered to the outer conductor of the coaxial cable.

By doing so, in addition to the advantages of each aspect mentioned above, it becomes possible to suitably solder the connecting piece and the outer conductor of the coaxial cable together to surely connect the shield cover with the coaxial cable through the tongue flap. Furthermore, the surface tension of the melted solder is surely intercepted at the bent portion of the connecting piece to surely prevent the melted solder from spreading along the tongue flap, and consequently it is surely prevented that the solder rises higher than the height of the base surface of the shield cover by the bent portion.

The entire disclosure of Japanese Patent Application No. 2006-239053 filed on Sep. 4, 2007, including description, claims, drawings and summary are incorporated herein by reference in its entirety.

Although various exemplary embodiments have been shown and described, the invention is not limited to the embodiments. Therefore, the scope of the invention is intended to be limited solely by the following claims.

Antenna apparatus

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Description

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Priority Claims (1)