JPH10163734A - Antenna device - Google Patents

Abstract

(57) [Problem] To provide a small and lightweight antenna device suitable for a portable receiver. SOLUTION: A conductor having a predetermined width is attached to a side surface of a core material 2 so as to make substantially one round to form a tuning coil 3, and conductors 7, 10 or a core material formed on an opening surface of the core material 2 are formed. When 2 is mounted on the wiring board 14, the conductors 15 and 19 formed on the wiring board 14 form a coil electromagnetically coupled to the tuning coil 3 connected to an external antenna.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device used for a battery-operable portable receiving device such as an FM or TV.

[0002]

2. Description of the Related Art In recent years, the service of FM multiplex broadcasting has been started, and the contents of the programs have been diversified, and a paging service (FM pager) will be implemented in the near future. Conventionally, these receiving devices require a rod antenna or an antenna using a headphone lead as a device for receiving a radio wave, and it is necessary to always extend the rod antenna or wear headphones when receiving broadcast. In FM and TV receivers, the length of the above antenna depends on the frequency of the received radio wave,
When receiving a domestic FM broadcast, it is necessary to use an antenna having a length of about 1 m.

[0003]

When the receiving device is operated with the above-mentioned conventional rod antenna or an antenna using a headphone lead, it is necessary to extend a long rod antenna and attach a headphone. Is inconvenient, and is not practical as an antenna for a portable receiver such as a pager receiver.

[0004]

According to the present invention, in order to solve the above-mentioned problems, an antenna device according to a first aspect of the present invention is provided such that a band-shaped first conductor having a predetermined width is attached to a side surface of a core material so as to make substantially one round. A first coil for tuning is formed, and both ends of the first conductor are used as output terminals, and a surface of the core material substantially perpendicular to a side surface of the core material is used as an opening surface of the antenna. It is characterized by.

Therefore, according to the above configuration, it is only necessary to attach a conductor having a predetermined width to the side surface of the core material, so that the antenna device is small and lightweight and easy to manufacture, and is inexpensive and can be used for various types of portable receiving devices. An antenna device suitable for the device can be obtained.

[0006] The antenna device according to the second aspect is the first aspect.
A second coil is provided for connecting to an external antenna formed by attaching a band-shaped second conductor in the opening surface of the antenna device described above, and both ends of the second conductor are connected to the second coil. The terminal is characterized by.

Therefore, according to the above configuration, the second conductor is attached to the opening surface of the core member having the first coil for tuning on the side surface, and the second conductor is connected to the external antenna. Therefore, the second coil can be formed without increasing the size of the core material, and an antenna device provided with the second coil for connecting to a small and inexpensive external antenna suitable for a portable receiving device is obtained. be able to.

[0008] The antenna device according to the third aspect is the first aspect.
A third strip-shaped conductor whose one end extends to a boundary with the side surface of the core material is attached to an opening surface of the antenna device according to the above aspect, and protrudes from the first conductor at an intermediate point of the first coil. An intermediate tap is formed, and one end of the third conductor is connected to an intermediate tap protruding from the first conductor on the side surface of the core material, and the third conductor and the first coil are connected to each other. A third coil for connecting to an external antenna is formed by a part of the first conductor to be formed.

Therefore, according to the above configuration, the third conductor is provided on the opening surface of the core material provided with the first coil for tuning on the side surface, and the third conductor is connected to the end of the opening surface of the core material. Since it is connected to the intermediate tap of the first coil formed on the side surface at the part,
The third coil for connecting to the external antenna can be formed by a part of the third conductor and the first conductor forming the first coil, and the external antenna can be formed without increasing the core material. An antenna device provided with a coil for connection can be obtained.

[0010] The antenna device according to the fourth aspect is the first aspect.
An annular fourth conductor having an opening in a part thereof is provided on a wiring board to which the antenna device according to the above is attached, facing the opening surface of the core material of the antenna device, and the fourth conductor is used for an external antenna. Forming a fourth coil for connection, and a first coil for tuning;
The first coil and the fourth coil are electromagnetically coupled in a state in which the core material having the above-mentioned coil is attached to the wiring board.

Therefore, according to the above configuration, the first coil formed of the first conductor formed on the core material includes the fourth conductor provided on the wiring board when the core material is mounted on the wiring board. It is electromagnetically coupled to the fourth coil. Therefore, the coil connected to the tuning coil can be formed to connect to the external antenna without forming a special pattern on the core material side.

[0012] The antenna device according to the fifth aspect is the first aspect of the invention.
A fifth conductor provided on a wiring board to which the antenna device according to the above is attached, the fifth conductor having one end extending to a predetermined position facing an opening surface of the core material of the antenna device and facing a side surface of the core material; Forming an intermediate tap projecting at an intermediate point of the first coil formed on the side surface of the fifth conductor, connecting one end of the fifth conductor extending to a predetermined position to the intermediate tap,
A fifth coil connected to an external antenna is formed by a part of the fifth conductor and the first conductor forming the first coil.

Therefore, according to the above configuration, when the core material having the tuning first coil formed on the side surface is attached to a predetermined position of the wiring board, the intermediate tap protrudingly provided at the intermediate point of the first coil is provided. Are connected to one end of the fifth conductor formed on the wiring board so as to face each other, and are part of the fifth conductor formed on the wiring board and the first conductor provided on the side surface of the core material; A fifth coil is electromagnetically coupled to a tuning coil for connection to an external antenna. Also in this configuration, it is possible to form a coil for connecting to an external antenna coupled to a tuning coil without increasing the size of the core material.

[0014]

Embodiments of the present invention will be described below. The present invention utilizes a loop antenna using a core material, and aims to reduce the size of an antenna device.

(Embodiment 1) First, a basic structure of a loop antenna using a core material will be described. FIG. 1 is a perspective view of a basic structure of a loop antenna 1, wherein a one-turn coil 3 formed by attaching a conductor such as a band-shaped copper foil having a width T to a side surface of a rectangular parallelepiped core material 2 is provided. Both ends of the coil 3 are output terminals 4. The upper surface of the core material 2 is an opening of the loop antenna, and S represents the opening area. In order to improve the receiving performance of the loop antenna 1, it is necessary to increase the Q of the antenna or increase the opening area S.

FIG. 2 shows a configuration of an antenna circuit using the loop antenna 1 described above. A tuning variable capacitor 5 is provided in parallel with the output terminal 4 of the loop antenna 1, and a tuning circuit is formed by the coil 3 of the loop antenna 1 and the tuning variable capacitor 5, thereby increasing the Q of the receiving antenna. When the capacitance of the tuning variable capacitor 5 is adjusted,
Tuning to a signal of a desired frequency, a radio wave of a desired station can be extracted, and the extracted reception signal is amplified by a high-frequency amplifier 6 at the next stage and output as an RF output to an FM, a TV tuner or the like.

The opening area S of the loop antenna 1 is determined by the inductance value L required for the loop antenna 1 using the core material 2, and the inductance value L is obtained as follows. Can be Maximum and minimum frequencies of radio waves to be received (reception band)
Thus, the variable capacitance ratio (maximum capacitance value / minimum capacitance value) of the tuning variable capacitor 5 is determined. The minimum receiving frequency is f
And _LOW, if the maximum capacity value of the variable capacitor 5 and the C _MAX, the value L of the inductance required for the loop antenna 1 using the above core material 2 is _{L = 1 / (2πf LOW)} 2
× C _MAX .

The inductance value L of the loop antenna 1 using the core material 2 is as follows in the case of the structure shown in FIG.
The value increases when the opening area S of the loop antenna 1 is increased, and decreases when the opening area S is reduced. However, in this case, the width T of the coil 3 is assumed to be constant. When the opening area S is constant, the coil 3
When the width T of the coil 3 is reduced, the inductance value L increases, and when the width T of the coil 3 is increased, the inductance value L decreases.

Therefore, when the inductance value L and the opening area S of the loop antenna 1 using the core material 2 are determined, the required value of the inductance L of the loop antenna 1 is determined by selecting the width T of the coil 3. Can be obtained. One-turn coil 3 provided on the side surface of core material 2
Can be formed by sticking a metal plate or a copper foil tape, and the coil 3 having a constant width T can be easily obtained. According to the above description, a loop antenna using a core material can be realized.

(Embodiment 2) FIG. 3 shows a second embodiment of the present invention, in which parts corresponding to those in FIG. In this embodiment, a secondary winding for connecting an external rod antenna, an antenna using a headphone lead, or the like to a loop antenna using a core material is provided.

In FIG. 3, a one-turn coil 3 made of a conductor having a width T is formed on the side surface of the core material 2 of the loop antenna 1-1, and this coil 3 serves as a tuning coil. A coil 7 serving as a one-turn secondary winding is formed on the upper surface of the core member 3. Terminals 8 provided at both ends of the coil 7 are connected to external rod antennas or antennas using a headphone lead. It becomes a terminal connected to the antenna. In the figure, H indicates the height of the side surface of the core material 2.
The tuning coil 3 and the coil 7 for connection to the external antenna serving as the secondary winding are formed in the same manner as in the embodiment shown in FIG.

The one-turn coil 3 for tuning of the loop antenna has a predetermined opening area S and a width T of the coil 3 needs to be a predetermined value in order to obtain a predetermined inductance value L. . Therefore, when the coil 7 serving as a secondary winding for connecting to an external antenna is formed side by side with the coil 3 for tuning on the side surface of the core material 2, the height H of the side surface of the core material 2 increases, 2 becomes large, which is not preferable as an antenna circuit of a portable receiver. In this embodiment, since the coil 7 serving as the secondary winding is formed in the opening on the upper surface of the core material 2, the degree of freedom in designing the coil 7 is increased, and the core material is not increased. A small antenna can be obtained.

(Embodiment 3) FIG. 4 shows a third embodiment of the present invention, in which parts corresponding to those in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof will be omitted. This embodiment has a structure in which a part of a coil serving as a secondary winding for connection to an external antenna is also used as a part of a tuning coil.

In FIG. 4, a one-turn tuning coil 3 made of a conductor having a width T is provided on the side surface of the core material 2 of the loop antenna 1-2, and output terminals 9 are provided at both ends of the coil 3.
-1 and 9-2 are provided. Also, an L-shaped conductor 10 is formed in the opening on the upper surface of the core material 2, a terminal 11 is provided at one end of the conductor 10, and the other end of the conductor 10 is 2 and connected to the intermediate tap portion 12 of the coil 3 for tuning.

Accordingly, the L-shaped conductor 10 is integrated with a part of the coil 3 through the intermediate tap portion 12 of the coil 3 to form a secondary winding for connecting to a one-turn external antenna. The terminal of the coil 13 is the terminal 11 provided at one end of the L-shaped conductor 10 and the other terminal 9-2 of the coil 3 for tuning. Also in this case, the coil 3, the intermediate tap 12, and the L-shaped conductor 10 are formed in the same manner as in the first and second embodiments.

In this case, the grounding terminal (GND) of the tuning coil 3 and the coil 13 serving as the secondary winding is connected to the terminal 9.
−2, which becomes a common terminal. In this embodiment, since a part of the coil 13 serving as the secondary winding is provided in the opening on the upper surface of the core material 2, the degree of freedom in designing the secondary winding is increased as in the second embodiment, and the core material 2 is Without increasing the size, a small antenna can be provided, and the position of the intermediate tap can be set freely.

(Embodiment 4) FIG. 5 shows a fourth embodiment of the present invention. The parts corresponding to those in FIGS. 1 to 4 are denoted by the same reference numerals, and description thereof is omitted. In this embodiment, when a coil serving as a secondary winding for connection to an external antenna is formed on the wiring board side and the core material provided with the tuning coil is attached to the wiring board, the two coils are connected. It is something to do.

In FIG. 5, a one-turn tuning coil 3 made of a conductor having a width T is provided on the side surface of the core material 2 of the loop antenna 1-3, and output terminals 13 are provided at both ends of the coil 3.
-1, 13-2 are provided.

On the other hand, when the loop antenna 1-3 is mounted on the wiring board 14 on which the loop antenna 1-3 is mounted, one turn of the loop antenna 1-3 is provided at a position facing the lower surface of the core material 2 of the loop antenna 1-3. Coil 1 to be secondary winding
5 is formed as a pattern on the wiring board 14. The terminals 16-1 and 16-2 at both ends of the coil 15
Are wired to terminals connected to an external antenna (not shown) on the wiring board 14, and are provided on the core material 2 when the loop antenna 1-3 is attached to the wiring board 14. Both output terminals 13- of the coil 3 for tuning
Terminals 17-1 and 17-2 to which terminals 1 and 13-2 are connected are provided.

Therefore, the loop antenna 1 is
-3 attached, core material 2 of loop antenna 1-3
The one-turn tuning coil 3 formed on the side surface of the wiring and the coil 15 serving as a one-turn secondary winding formed on the wiring board 14 face the opening surface in common, and both coils are electromagnetically coupled. I do. In this case, the coil 15 serving as the secondary winding can be formed at the same time when the pattern of the wiring board 14 is formed, and can be manufactured with high accuracy and at low cost. Further, the design of the coil 15 can be freely set with respect to the opening surface of the loop antenna as in the other embodiments, and a small and high-performance antenna can be provided. In this case, the coil 3 may be formed in the same manner as in the other embodiments described above.

(Embodiment 5) FIG. 6 shows a fifth embodiment of the present invention, in which parts corresponding to those in FIGS. 1 to 5 are denoted by the same reference numerals, and description thereof will be omitted. In this embodiment, when a part of a coil serving as a secondary winding for connection to an external antenna is formed on a wiring board side and a core material provided with a tuning coil is attached to the wiring board, the wiring A part of the coil formed on the substrate and a part of the tuning coil formed on the core material form a coil which is a secondary winding.

In FIG. 6, a one-turn tuning coil 3 made of a conductor having a width T is provided on the side surface of the core material 2 of the loop antenna 1-4, and output terminals 13 are provided at both ends of the coil 3.
-1, 13-2 are provided, and an intermediate tap portion 18 is formed in an intermediate portion of the coil 3.

On the other hand, when the loop antenna 1-4 is attached to the wiring board 14 to which the loop antenna 1-4 is attached, a conductor 19 is provided at a position facing the lower surface of the core material 2 of the loop antenna 1-4. It is formed as a wiring pattern of the wiring board 14. At one end of the conductor 19, a terminal 20 to which the intermediate tap portion 18 of the coil 3 is connected when the loop antenna 1-4 is attached to the wiring board 14 is formed. 3 and a coil for connecting to an external antenna serving as a secondary winding between a terminal 21 provided at the other end of the conductor 19 and the output terminal 13-2 of the coil 3. To form Both output terminals 13-1, 13-2 of the coil 3
Are the terminals 17-1 and 17-2 provided on the wiring board 14 when the loop antenna 1-4 is mounted on the wiring board 14.
Connected to.

Therefore, the loop antenna 1 is
When -4 is attached, both output terminals 13-1 and 13-2 of the coil 3 formed on the loop antenna 1-4 are connected to terminals 17-1 and 17-2 formed on the wiring board 14, respectively. 3 is provided on the wiring board 1.
4 is connected to the terminal 20 provided in the terminal 4. Therefore, the wiring board 1
A secondary coil composed of a conductor 19 and a part of the coil 3 is formed between a terminal 21 formed at one end of the conductor 19 and one output terminal 17-2 of the coil 3. The secondary coil is electromagnetically coupled to the tuning coil 3.

In this case, since the conductor 19 forming a part of the coil serving as the secondary winding can be formed simultaneously with the wiring pattern of the wiring board 14, it can be manufactured at low cost and with high accuracy. Further, the design of the secondary side coil can be freely set with respect to the opening surface of the loop antenna similarly to the other embodiments, and a small and high performance antenna can be supplied. Also in this case, the coil 3 may be formed in the same manner as in the other embodiments described above.
The ground terminal (GND) of the tuning coil 3 and the coil serving as the secondary winding is the terminal 13-2, and is a common terminal as in the embodiment shown in FIG.

[0036]

According to the present invention having the above-described structure, a small and lightweight antenna circuit can be provided. In addition, a coil serving as a secondary winding for connecting to an external antenna is attached to the surface of the core material orthogonal to the surface of the core material forming the tuning coil formed by attaching the conductor foil by attaching the conductor foil. Since the molding is performed, the secondary winding can be formed without increasing the size of the core material. The secondary winding can also serve as a part of a tuning coil. In this case, the secondary winding can be made compact without increasing the size of the core material.

According to the present invention, a coil for connecting to an external antenna is formed simultaneously with a wiring pattern on a wiring board, and a coil for tuning is formed by attaching a conductive foil to the core material. The coil formed on the wiring board can be formed with high precision at the same time as the formation of the wiring pattern. A small and lightweight antenna circuit can be provided without having to increase the size of the material itself.

[Brief description of the drawings]

FIG. 1 is a perspective view of a first embodiment of the present invention.

FIG. 2 is a circuit diagram of a main part of the present invention.

FIG. 3 is a perspective view of a second embodiment of the present invention.

FIG. 4 is a perspective view of a third embodiment of the present invention.

FIG. 5 is a perspective view of a fourth embodiment of the present invention.

FIG. 6 is a perspective view of a fifth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 loop antenna 1-1, 1-2, 1-3, 1-4 loop antenna 2 core material 3, 8, 15 coil 4 output terminal 7 coil 9-1, 9-2 output terminal 10 conductor 11 terminal 12 middle tap 13-1, 13-2 Output terminal 14 Wiring board 16-1, 16-2 Terminal 18 Intermediate tap 19 Conductor 20, 21 Terminal

Claims (5)

[Claims] 1. A first coil for tuning, which is formed by applying a band-shaped first conductor with a predetermined width so as to make substantially one round on a side surface of a core material, is provided, and both ends of the first conductor are connected to each other. An antenna device as an output terminal, wherein a surface of a core material substantially orthogonal to a side surface of the core material is an opening surface of the antenna. 2. A second coil for connecting to an external antenna formed by attaching a band-shaped second conductor in an opening surface of the antenna device according to claim 1, wherein the second coil is connected to an external antenna. An antenna device wherein both ends are terminals of the second coil. 3. A band-shaped third conductor, one end of which extends to a boundary with the side surface of the core material, is attached to an opening surface of the antenna device according to claim 1, and is located at an intermediate point of the first coil. Forming an intermediate tap protruding from the first conductor in the third conductor;
The above-mentioned one end of the conductor is connected to an intermediate tap protruding from the side of the core material to the first conductor, and the third conductor and a part of the first conductor forming the first coil are externally connected. An antenna device, wherein a third coil for connecting to an antenna is formed. 4. An annular fourth conductor having an opening in a part thereof is provided on a wiring board on which the antenna device according to claim 1 is mounted, facing an opening surface of a core material of the antenna device, A fourth coil connected to the external antenna is formed by the fourth conductor, and the first coil is connected to the wiring substrate in a state where the core material on which the first coil for tuning is formed is mounted on the wiring board. Characterized in that the antennas are electromagnetically coupled. 5. A wiring board on which the antenna device according to claim 1 is mounted, the first end of which extends to a predetermined position facing an opening surface of a core material of the antenna device and one end of which faces a side surface of the core material. 5 conductor, a middle tap protruding at a middle point of the first coil formed on the side surface of the core material, and one end extending to a predetermined position of the fifth conductor is used as the middle tap. An antenna device, wherein a fifth coil connected to an external antenna is formed by a part of the first conductor that is connected to form the fifth conductor and the first coil.