JP2546351Y2 - antenna - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna for receiving a high-frequency signal in a pager, a cordless phone or the like.

[0002]

2. Description of the Related Art FIGS. 5 and 6 are views showing a conventional antenna, FIG. 5 is a perspective view of the antenna, and FIG.
FIG. 6B shows an equivalent circuit of the antenna when viewed from the direction.

In the figure, 1 is a ferrite core, 2 is a chip capacitor, 3 is a printed board, 4 is a metal cap, 5 is an external terminal, 6 is a solder, 7 is a cut-out projection, L is a coil, C _{1 to} C ₄ Indicates a capacitor, and T ₁ and T ₂ indicate terminals.

Conventionally, for example, a pager antenna has been configured as shown in FIGS. In this example,
A printed circuit board 3 on which a plurality of (for example, four) chip capacitors 2 are mounted is adhered to one surface of a ferrite core 1 having a rectangular parallelepiped shape, and the periphery of the ferrite core 1 is surrounded by a metal case (conductor) 4.

[0005] Then, the printed board 3 and the opening edge of the metal cap 4 are fixed by solder 6 to be integrated. In this case, the metal cap 4 is used as a one-turn coil, and is electrically connected to each of the chip capacitors 2.

A cut-and-raised protrusion 7 is provided at the edge of the opening of the metal cap 4 to prevent the chip capacitor 2 from coming into contact with the mounting surface of the motherboard when the antenna is mounted on the motherboard, for example.

FIG. 6B shows an equivalent circuit of the antenna having the above configuration. That is, the metal cap 4 serves as a coil L, and the chip capacitor 2 includes capacitors C _{1 to} C
It becomes ₄ . The capacitors C _{1 to} C ₄ and the coil L constitute an LC parallel resonance circuit. The resonance frequency f _o of the LC parallel resonance circuit, for example, 50 MHz, 150MH
z, 900 MHz or the like, and receives a high-frequency signal of the frequency.

[0008]

Problems to be Solved by the Invention The above-mentioned conventional devices have the following problems. (1) A gap G is formed between the metal cap 4 and the ferrite core 1 due to the thickness of the printed circuit board 3. For this reason, the antenna becomes thick, and miniaturization is difficult.

(2) Since the gap G is formed, the adhesion of the metal cap 4 to the ferrite core 1 is poor, and the characteristics as an antenna are deteriorated. In addition, the characteristics of the antenna vary due to the variation of the gap G.

(3) When the printed circuit board 3 is bonded to the ferrite core 1, the position of the printed circuit board 3 cannot be determined.
It is necessary to position the printed circuit board 3 with respect to the ferrite core 1 using a special jig, and to perform bonding. Therefore, workability is poor.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a conventional problem, to reduce the size and weight of the antenna, to reduce variations in characteristics, and to improve the workability of assembling the antenna.

[0012]

FIG. 1 is a view for explaining the principle of the present invention, and the same reference numerals as those in FIGS. 5 and 6 denote the same parts.
1A is a magnetic core, 2A is a capacitor, 8 is an end, 9 is an opening edge, 10 is a recess, and g is a gap (portion without a conductor).
Is shown.

The present invention has the following configuration to solve the above problems. (1) An antenna including a magnetic core 1A having a flat portion at least in part, a metal cap 4 surrounding the magnetic core 1A, and a capacitor 2A connected to the metal cap 4; 1A
Allowed, provided with a gap g between both open end edges 9,9 of the metal cap 4 on the flat portion of the magnetic core 1A, the both open edges 9,9 and holds storage capacitor 2A A holding portion is provided integrally with the metal case, and further,
The metal cap 4 has one external terminal 5 and one raised projection.
Provided physically, housing the capacitor 2A in the holding portion,
The capacitor 2A was connected to the metal cap 4.

(2) In the configuration (1), the periphery of the end of the metal cap 4 and the magnetic core 1A are fixed with an adhesive. (3) In the configuration (1), the holding unit and the capacitor 2
The terminal A was fixed by soldering. (4) In the configuration (1), a ferrite core is used as the magnetic core.

[0015]

The present invention is constructed as described above, and has the following effects. When assembling the antenna, magnetic core 1A
(For example, a ferrite core) is covered with a metal cap 4 and the periphery of the end of the metal cap 4 is bonded to the magnetic core 1A with an adhesive.

When connecting the capacitor 2A to the metal cap 4, the capacitor 2A is housed in a holding portion (for example, the concave portion 10) and temporarily fixed, and then both terminals of the capacitor 2A are soldered by soldering. Connect and fix to the holder.

This makes it possible to connect a capacitor to the metal cap 4 without using a printed circuit board as in the prior art.
While being smaller and lighter than conventional antennas,
During the connection work of the capacitor 2A, the capacitor 2A can be temporarily fixed by the holding portion, so that the positioning of the capacitor can be easily performed, and the workability is improved.

When the antenna is used, the metal cap 4 serves as a coil, and the coil and the capacitor 2A constitute an LC parallel resonance circuit. In this case, since the metal cap 4 and the magnetic core 1A are in close contact with each other,
Compared to conventional antennas, there is less variation in characteristics,
Moreover, the characteristics of the antenna are improved.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. 2 to 4 are views showing an antenna according to an embodiment of the present invention. FIG. 2A is a perspective view before storing a capacitor, FIG. 2B is a perspective view after storing a capacitor, and FIG. 3C is a perspective view of a completed antenna. FIG. 3D is a sectional view taken along line ST of FIG. 2B,
4E shows an equivalent circuit of the antenna, and FIG. 4F shows a mounting diagram of the antenna.

In the figure, the same reference numerals as those in FIG. 1 denote the same parts.
11 is a hollow portion, 12 is a solder, 13 is an adhesive, 1
4 motherboard 15 solder, L ₁₀ is a coil, C _10,
C ₁₁ is a capacitor, T _1, T ₂ denotes the terminal.

The antenna of this embodiment is a pager antenna and is used for receiving a high-frequency signal. This antenna constitutes an LC parallel resonance circuit equivalently as in the conventional example, but an example in which two chip capacitors are used as the capacitors of the circuit will be described.

Hereinafter, description will be made along the order of manufacturing the antenna. First, a ferrite core 1 as a magnetic core of a coil,
The metal cap 4 as a coil is separately manufactured. As shown in FIG. 2A, the ferrite core 1 is manufactured so that its outer shape is substantially a rectangular parallelepiped.

Since the metal cap 4 serves as a coil, the metal cap 4 is made of a conductor having a predetermined resistance value as shown in FIG.
A is formed into a shape as shown in FIG. Then, a metal cap 4 is placed so as to surround the periphery of the ferrite core 1, and an end of the metal cap 4 (the ferrite core 1 shown in FIG.
(The part located on the upper surface side) of the ferrite core 1 is adhered to the surface of the ferrite core 1 with an adhesive to fix (integrate) the metal case 4 and the ferrite core 1.

In this case, the metal cap 4 and the ferrite core 1 are brought into a state of being substantially in close contact with each other.
The dimensions are set so as to form a predetermined gap g between the open edges 9 of the metal cap 4.

Also, both open edges 9, 9 of the metal cap 4 are provided.
In this case, a pair of recesses (holding portions) 10 for housing and holding and temporarily fixing the chip capacitors 2 are provided for each of two locations, and a total of four locations (in this example, there are two chip capacitors, so the recesses are At four locations).

Further, around the end 8 of the metal cap 4, the external terminal 5 and the cut-and-raised protrusion 7 are formed at a plurality of places, and the hollow portion 11 is formed at a plurality of places. Then, by forming the hollow portion 11 to the portion behind the concave portion 10, the conductor width (conductor constituting the metal cap) of the concave portion 10 is reduced.

Next, as shown in FIG. 2B, the chip capacitor 2 is inserted between the two pairs of concave portions 10,
Perform temporary fixing. Thereafter, the terminals of the chip capacitor 2 and the conductors of the recess 10 (conductors constituting the metal cap 4)
Are electrically connected and mechanically fixed by the solder 12 (see FIGS. 3C and 3D).

Finally, as shown in FIG. 3C, an adhesive 13 is dropped or applied around the end 8 of the metal cap 4 to obtain a completed antenna. This adhesive 13
Protects the surface of the metal cap 4
It is provided to improve the adhesion between the ferrite core 1 and the metal cap 4 or to further firmly fix the ferrite core 1 to the metal cap 4.

FIG. 4E shows an equivalent circuit of the antenna completed as described above. That is, the metal cap 4 is a coil L ₁₀ of 1 turn, this ferrite core 1 has a magnetic core of the coil L _10.

The two chip capacitors 2 become capacitors C ₁₀ and C ₁₁ , respectively, and an LC parallel resonance circuit is formed between the terminals T ₁ and T ₂ . And this LC
The resonance frequency f _o of the resonance circuit is set to match the frequency of the high frequency signal received by the pager.

FIG. 4F shows the antenna mounted on a motherboard in a pager. As shown in the figure, when mounting the antenna on the motherboard 14, the external terminal 5 of the antenna is inserted into a component insertion hole provided in the motherboard 14, and the solder 15 And is connected to a predetermined circuit pattern.

At this time, the tip of the cut-and-raised projection 7 provided on the metal cap 4 comes into contact with the surface of the motherboard 14,
The chip capacitor 2 does not contact the motherboard 14. Thus, protection of the chip capacitor 2 and insulation between the antenna and other conductors on the motherboard 14 are performed.

(Explanation of Other Embodiments) Although the embodiments have been described above, the present invention can be implemented as follows. (1) The number of capacitors connected to the metal cap may be one or more and an arbitrary number. Further, the capacities of the capacitors may be all the same, may be all different capacities, and may be selected to any capacity.

(2) The antenna of the present invention may be an insertion part as in the above embodiment, but may be a surface mounting part by changing the structure of the external terminals. In order to form this surface-mounted component, external terminals may be formed on the side surface of the antenna (the side surface when mounted on a motherboard or the like).

(3) By bending the external terminal in the above embodiment toward the surface on which the capacitor is provided, it is also possible to make a component having the terminal provided on the bottom surface of the antenna (the bottom surface when mounted on a motherboard or the like). It is.

(4) The magnetic core is not limited to a ferrite core, and other magnetic materials may be used. (5) It can be used not only as an antenna for pagers but also as an antenna for cordless phones.

(6) The holding portion for housing and holding the capacitor is not limited to the concave portion 10 as in the above-described embodiment, but any structure having a structure capable of holding the terminals provided at both ends of the capacitor can be used. Any shape may be used.

[0038]

[Effects of the Invention] As described above, the present invention has the following effects. (1) A capacitor can be connected to a metal cap without using a printed circuit board as in the conventional example. Therefore,
The size and weight of the antenna can be reduced by the amount of the printed circuit board, and the price of the antenna can be reduced.

(2) The metal cap and the ferrite core are in close contact with each other, and no gap G is formed unlike the conventional example. Therefore, variations in antenna characteristics are eliminated, and the antenna characteristics are improved and stabilized.

(3) The capacitor can be temporarily fixed using the concave portion provided at the opening edge of the metal cap, and then the capacitor can be connected to the metal cap by soldering. Therefore, the positioning of the capacitor is facilitated, and the workability is improved. In addition, since it is not necessary to use a special jig as in the conventional example, the antenna can be easily manufactured at this point and an inexpensive antenna can be obtained.

(4) Since only soldering is required for the terminals of the capacitor and the concave portions, the work time and work are reduced as compared with the conventional example. (5) The conductor width around the concave portion for housing the capacitor is narrow, and a hollow portion is formed behind the concave portion. And
When soldering the terminals of the capacitor or when using the antenna, if the temperature near the concave portion becomes high, the metal in the concave portion may thermally expand.

In such a case, the thermally expanded metal spreads to the hollow portion, and no extra force is applied to the capacitor.
Therefore, the capacitor can be protected without cracking. (6) Since the metal cap is provided with cut-out projections,
When the antenna is attached to the motherboard,
The tip of the projection comes into contact with the surface of the motherboard and the chip
Make sure that capacitor 2 does not touch the motherboard
Can be. As a result, protection of chip capacitors and
Provide insulation between the antenna and other conductors on the motherboard
Can be. (7) Since the external terminals are provided integrally with the metal cap,
External terminals can be manufactured simultaneously in the metal cap manufacturing process.
Can be. Therefore, the antenna manufacturing process is simplified.
Cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a diagram illustrating an antenna (part 1) according to one embodiment of the present invention;

FIG. 3 is a diagram illustrating an antenna (part 2) according to one embodiment of the present invention;

FIG. 4 is a diagram illustrating an antenna (part 3) according to one embodiment of the present invention;

FIG. 5 is a diagram showing a conventional antenna (No. 1).

FIG. 6 is a diagram showing a conventional antenna (part 2).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ferrite core 1A Magnetic core 2 Chip capacitor 2A capacitor 4 Metal cap 5 External terminal 6, 12, 15 Solder 7 Cut-and-raised projection 8 End of metal cap 9 Opening edge of metal cap 10 Concave part 11 Hollow part 13 Adhesive 14 Motherboard

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-51-83755 (JP, A) JP-A-57-15502 (JP, A) Japanese Utility Model Sho 62-32613 (JP, U) Japanese Utility Model Sho-48 25638 (JP, U) Fully open 1983-34763 (JP, U) Fully open 1984-171325 (JP, U)

Claims (4)

(57) [Scope of request for utility model registration] A magnetic core (1) having a flat portion at least partially.
A), a metal cap (4) surrounding the magnetic core (1A), and a capacitor (2A) connected to the metal cap (4), wherein the metal cap (4) is connected to the magnetic core (1A). )
A gap (g) is provided between the open edges (9, 9) of the metal cap (4) on the plane portion of the magnetic core (1A), and the gap (g) is provided on the open edges (9, 9). Is provided with a holding portion for accommodating and holding the capacitor (2A) integrally with the metal case.
The metal cap (4) further includes an external terminal.
(5) An antenna characterized in that a cut-and-raised projection (7) is provided integrally , a capacitor (2A) is housed in the holding portion, and the capacitor (2A) is connected to the metal cap (4). 2. An antenna according to claim 1, wherein the magnetic core (1A) and the periphery of the end of the metal cap (4) are fixed with an adhesive. 3. The antenna according to claim 1, wherein the holding portion and a terminal of the capacitor are fixed by soldering. 4. An antenna according to claim 1, wherein a ferrite core (1) is used as said magnetic core (1A).