JPH10341105A - Antenna system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an antenna for a mobile radio portable equipment that is mainly operated for two frequency bands in common, wherein the impedance characteristic can be adjusted after manufacture. SOLUTION: A high frequency current induced in a 2nd parasitic coil 17 gives effect on a current distribution and an impedance of a 1st coil 16. Thus, the amplitude and the phase of the high frequency current are controlled by a length and a pitch of the 2nd coil 17 and a position of the 2nd coil 17 with respect to the 1st coil 16. A ceiling plate 18 is freely elevated/descended/rotated on an inner circumferential face of a bobbin 15 by an adjustment lug 18a, thereby changing the pitch of the 2nd coil 17 and the position of the 2nd coil 17 with respect to the 1st coil 16. Thus, the impedance characteristic of an antenna section 21 is controlled and a desired frequency band is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil antenna used mainly as a part of a telescopic antenna used in a mobile radio, and more particularly to a coil type antenna which can flexibly cope with a plurality of frequency bands. The present invention relates to a modified antenna device.

[0002]

2. Description of the Related Art Recently, with the diversification of mobile communication, the frequency bands used have been diversified, for example, to 800 MHz band, 1.5 GHz band and 1.9 GHz band. There is a demand for a wireless device that can share the same. To achieve this, it is necessary to design an antenna having two or more different frequency bands.

Referring to FIG. 10, a whip antenna of a conventional mobile radio portable device will be described.

[0004] The whip antenna 1 includes a monopole antenna element 2 and an antenna unit 3. Here, when the whip antenna 1 is extended, the monopole antenna element 2 is connected from the first contact 5 to the power supply contact piece 11 and the power supply line 10 set on the radio transceiver body 7.
Is connected to the antenna matching circuit 8 via the. When the whip antenna 1 is stored, the antenna unit 3
Is connected to the antenna matching circuit 8 from the second contact 6 via the power supply contact piece 11 and the power supply line 10. The antenna matching circuit 8 is connected to a radio circuit 9 operating in the frequency band A. Further, the antenna matching circuit 8 has a frequency band A
Has a function of converting the impedance of the monopole antenna element 2 into a desired impedance, and a function of converting the impedance of the antenna unit 3 into a desired impedance.

When the whip antenna 1 is pulled out of the wireless device main body 7, the impedance when the whip antenna 1 is viewed from the first contact 5 is Z 1, and when the whip antenna 1 is stored in the wireless device body 7, The impedance of the antenna unit 3 is controlled such that Z1 = Z2, where Z2 is the impedance when the antenna unit 3 is viewed from the two contact points 6. As a result, good matching can be obtained by the antenna matching circuit 8, and high-quality and stable mobile communication can be performed.

FIG. 11 shows in detail the antenna section 3 insulated and connected above the monopole antenna of the mobile radio portable device shown in FIG. Powered first
A first frequency band is formed by the coil 12 and a second frequency band is formed by the unpowered second coil 13, so that each of the two frequency bands can be controlled independently.

[0007]

However, since the antenna section 3 composed of the two coils is completely fixed to each other, it is impossible to adjust the impedance characteristics of the antenna section after manufacture. Met.

An object of the present invention is to solve such a conventional problem, and an object of the present invention is to realize an antenna device capable of adjusting an impedance characteristic of an antenna unit.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and has a mechanism capable of freely changing a positional relationship and a pitch of at least one coil constituting an antenna device. Therefore, an antenna device having desired impedance characteristics can be realized.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to an antenna device corresponding to first and second frequency bands, wherein the first antenna device has an impedance characteristic corresponding to the first frequency band. And a second coil having an impedance characteristic corresponding to a second frequency band provided inside the first coil. The first coil and the second coil for obtaining a desired impedance characteristic are provided. An antenna device provided with adjusting means for adjusting a positional relationship between coils, wherein a resonance frequency band and a VSWR value are easily adjusted by adjusting a positional relationship between a first coil and a second coil. It has the effect that it can be changed.

According to a second aspect of the present invention, the adjusting means is provided so as to be slidable on a cylindrical bobbin provided along the inside of the first coil and an inner peripheral surface of the bobbin. The second coil can be held at an arbitrary position in the first coil by fixing one end of the second coil to the top plate and sliding the top plate. 2. The antenna device according to claim 1, wherein the top plate is slid to change a positional relationship between the first coil and the second coil, thereby obtaining a resonance frequency band and a VSWR value of the antenna device. Has an effect that can be easily adjusted and changed.

According to a third aspect of the present invention, the adjusting means is provided along the inside of the first coil, and has a cylindrical bobbin having a thread groove on an inner peripheral surface thereof; And a disk-shaped top plate that engages with the first coil. One end of the second coil is fixed to the top plate, and the top plate is rotated along a screw groove provided on the bobbin, 2. The antenna device according to claim 1, wherein the second coil can be held at an arbitrary position in the first coil, and the first coil and the second coil are moved by sliding the top plate. By changing the positional relationship between the coils, the resonance frequency band and the VSWR value of the antenna device can be easily adjusted and changed, and the second coil can be more strongly held at an arbitrary position in the first coil. Having.

According to a fourth aspect of the present invention, one end of a second coil is fixed to a sliding portion slidably provided on an inner peripheral surface of a top plate, and 4. The antenna device according to claim 3, wherein the second coil can be held at an arbitrary position in the first coil by sliding the sliding portion. Since the second coil can be rotated without changing the position of the second coil, it has an effect of expanding the adjustment range of the impedance characteristic of the antenna device.

In the invention described in claim 5 of the present invention, the adjusting means has a disk-shaped top plate provided so as to be engaged with a part of the first coil at an outer peripheral portion thereof. The antenna device according to claim 1, wherein the second coil can be held at an arbitrary position in the first coil by rotating the top plate along the first coil. There is no need for a bobbin provided along the first coil, so that it can be manufactured at low cost and has an effect of eliminating the power loss of electromagnetic waves due to the bobbin.

According to a sixth aspect of the present invention, the top plate is slid so that desired impedance characteristics are obtained, and the top plate is fixed to the first coil. 5. The antenna device according to item 5, wherein the antenna device has an operation of preventing displacement of the second coil due to shock or vibration.

According to a seventh aspect of the present invention, the adjusting means is slidable on a cylindrical top plate fixed at least near one end of the first coil and an inner peripheral surface of the top plate. , And one end of the second coil is fixed to the sliding portion, and the sliding portion is slid.
2. The antenna device according to claim 1, wherein the first coil and the second coil can be held at an arbitrary position in the first coil.
Can be rotated, so that the adjustment range of the impedance characteristic of the antenna device can be expanded,
In addition, by reducing the number of movable parts by one, there is an operation that can be manufactured more easily.

According to the invention described in claim 8 of the present invention, the sliding portion slidably provided on the inner peripheral surface of the top plate is slid so that desired impedance characteristics are obtained. 8. The antenna device according to claim 4, wherein the moving part is fixed to the top plate, and has an operation of preventing displacement of the sliding part due to impact or vibration.

According to a ninth aspect of the present invention, in the antenna device according to any one of the first to eighth aspects, the second coil is formed of a rod-shaped conductor. Impedance characteristic different from the case where the antenna device is provided, and as a result, it has the effect of expanding the range of the adjustable impedance characteristic of the antenna device.

According to a tenth aspect of the present invention, the adjusting means is provided along the inside of the first coil and has a cylindrical bobbin having a thread groove on an inner peripheral surface thereof; An engaging portion that extends at least one of the coils and engages with the screw groove, and rotates the engaging portion along the screw groove so that the second coil is moved within the first coil. 2. The device according to claim 1, wherein the device can be held at an arbitrary position.
The antenna device described above does not require a top plate, so that it can be manufactured at low cost and has an effect of eliminating power loss of electromagnetic waves due to the top plate.

An eleventh aspect of the present invention is characterized in that the second coil is slid and the second coil is fixed to the bobbin so that desired impedance characteristics can be obtained. The antenna device according to claim 10,
The second coil has an operation capable of preventing a displacement of the second coil due to shock or vibration.

According to a twelfth aspect of the present invention, the first aspect
12. The antenna device according to claim 1, wherein the first frequency band is lower than the second frequency band, and the second frequency band is formed by the first coil. Has the function of adjusting the second frequency band at the position of the coil.

According to a thirteenth aspect of the present invention, there is provided an antenna apparatus corresponding to N (N is an integer of 3 or more) frequency bands, having an impedance characteristic corresponding to a first frequency band. One coil and N-1 coils or rod-shaped conductors provided inside the first coil and having impedance characteristics corresponding to respective frequency bands other than the first frequency band, and other than the first coil An antenna device characterized in that at least one of the coil or the rod-shaped conductor is configured to be movable inside the first coil, and has an action capable of having three or more frequency bands.

According to a fourteenth aspect of the present invention, at least one of the top plates is fixed to the bobbin by sliding the top plate so as to obtain desired impedance characteristics. Item 14. The antenna device according to Item 13, which has an effect of preventing displacement of the top plate due to shock or vibration.

According to a fifteenth aspect of the present invention, a terminal portion for electrically connecting to an electronic circuit is provided at one end, and a metal plug electrically connected to one end of the first coil is provided at the other end. 15. The antenna device according to claim 1, wherein one end of a second coil or a rod-shaped conductor is electrically connected to the plug. 16. By feeding power to these conductors, the impedance characteristics and directivity of the antenna device can be changed, thereby having the effect of expanding the adjustable range of the antenna device.

According to a sixteenth aspect of the present invention, there is provided an electronic device comprising: a terminal portion for electrically connecting to an electronic circuit at one end; and a metal plug electrically connected to one end of the first coil at the other end. 16. The antenna device according to claim 15, wherein an insulating layer is provided on an upper surface of the metal plug so that one end of the second coil and the metal plug are not electrically connected. This has the effect of changing the impedance characteristics and directivity of the device, thereby expanding the adjustable range of the antenna device.

According to a seventeenth aspect of the present invention, the second aspect
The second coil is configured to contract when one end of the coil comes into contact with a metal plug.
17. The antenna device according to 5 or 16, wherein by contracting the second coil, an impedance characteristic different from the impedance characteristic of the antenna device can be produced, and thereby the adjustable range of the antenna device can be expanded. Having.

An embodiment of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a sectional view of a main part of an antenna device according to a first embodiment of the present invention. In the figure, 19
Is a metal plug made of a conductive metal material, a second contact 6 for connecting to an electronic circuit is formed at one end, and an insulating layer 20 is formed on the other end plane. A cylindrical bobbin 15 made of an insulating resin and having a smooth inner peripheral surface is disposed and fixed on the insulating layer 20, and an impedance characteristic corresponding to a desired first frequency is formed on the outer peripheral surface of the bobbin 15. Is formed, and one end of the first coil 16 is electrically connected to at least one position of the metal plug 19. In addition, a top plate 18 that slides on the inner peripheral surface of the bobbin 15 is provided, an adjustment knob 18a that rotates integrally with the top plate 18 is provided on the top surface of the top plate 18, and a desired second plate is provided on the bottom surface. A second coil 17 having an impedance characteristic corresponding to the frequency is formed, and one end of the second coil 17 is press-fitted and fixed to a cylindrical projection 18b provided on the lower surface side of the top plate 18.

Further, since the second coil 17 has a spring property, the top plate 18 is pushed into the metal plug 19 side and its tip comes into contact with the insulating layer 20. Since it has, it can be contracted, and by changing the pushing amount, the winding pitch of the second coil 17 can be changed.

Reference numeral 18c denotes a fixing member for positioning and fixing the top plate 18 at a desired position on the inner peripheral surface of the bobbin 15 after adjustment, and at least one portion where the top plate 18 and the bobbin 15 are in contact with each other is made of resin or the like. It is stuck in.

According to this configuration, the high-frequency current induced in the non-power-supplied second coil 17 affects the current distribution and impedance of the first coil 16, so that the amplitude and phase of the high-frequency current are equal to those of the second coil 17. Can be controlled by changing the pitch of the second coil 17 and the position of the second coil 17 with respect to the first coil 16.

Therefore, by moving the top plate 18 up and down or rotating by sliding the top plate 18 on the inner peripheral surface of the bobbin 15 by the adjustment knob 18a provided on the upper surface of the top plate 18, the pitch of the second coil 17 and the first Can be changed with respect to the coil 16, thereby controlling the impedance characteristics of the antenna unit 21 and realizing an antenna device that can support two desired frequency bands.

(Embodiment 2) FIG. 2 is a sectional view of a main part of an antenna device according to a second embodiment of the present invention. In the figure, reference numeral 19 denotes a metal plug made of a conductive metal material, one end of which has a second contact 6 for connecting to an electronic circuit.
Is formed, and the insulating layer 20 is formed on the other end plane. A cylindrical bobbin 22 made of an insulating resin and having a thread groove 22a formed on a part of the inner peripheral surface thereof is formed on the insulating layer 20.
And a first coil 16 having an impedance characteristic corresponding to a desired first frequency is formed on an outer peripheral surface of the bobbin 22. One end of the first coil 16 is connected to at least a metal plug 19. It is electrically connected to one place. Further, a top plate 23 having a screw groove portion 23a rotatably engaged with a screw groove 22a provided on the inner peripheral surface of the bobbin 22 is provided. And a second coil 17 having an impedance characteristic corresponding to a desired second frequency is formed on the lower surface side,
One end thereof is press-fitted and fixed to a cylindrical projection 23c provided on the lower surface side of the top plate 23. 23d is the top plate 23
Is a fixing member for positioning and fixing at a desired position after rotation adjustment, and at least one portion where the top plate 23 and the bobbin 22 are in contact with each other is fixed with resin or the like.

With this configuration, the top plate 23 can be moved up and down along the screw groove 22a of the bobbin 22 by rotating and adjusting the adjustment groove 23b provided on the upper surface of the top plate 23 with a driver or the like. Like the first embodiment, the second
The pitch of the coil 17 and the second with respect to the first coil 16
Of the coil 17 can be controlled. As a result, the impedance characteristics of the antenna unit 25 can be easily controlled, and an antenna device that can support two desired frequency bands can be realized.

(Embodiment 3) FIG. 3 is a cross-sectional view of a main part of an antenna device according to a third embodiment of the present invention. The description is omitted. In the figure, a top plate 26 is provided with a sliding portion 27 configured to be slidable inside the top plate 26. With this configuration, by rotating and adjusting the sliding portion 27, the second coil with respect to the first coil 16 is adjusted. Since only the second coil 17 can be rotated at the position without changing the position of the coil 17, the adjustment range of the impedance characteristic of the antenna unit 28 can be widened.

(Embodiment 4) FIG. 4 is a sectional view of an essential part of an antenna device according to a fourth embodiment of the present invention. In the figure, reference numeral 19 denotes a metal plug made of a conductive metal material, one end of which has a second contact 6 for connecting to an electronic circuit.
Is formed, and the insulating layer 20 is formed on the other end plane. Then, a first coil 16 having an impedance characteristic corresponding to a desired first frequency is formed on the insulating layer 20, and one end of the first coil 16 is electrically connected to at least one place of the metal plug 19. Connected. A top plate 29 is provided on its outer peripheral surface so as to be engaged with the first coil 16, an adjustment knob 29 a is provided on the upper surface thereof, and an impedance characteristic corresponding to a desired second frequency is provided on the lower surface side. Is formed, and one end thereof is press-fitted and fixed to a convex portion 29b provided on the lower surface side of the top plate 29.

Reference numeral 29c denotes a fixing member for positioning and fixing the top plate 29 at a desired position inside the first coil 16 after the rotation of the top plate 29 is adjusted. At least one portion where 16 is in contact is fixed with resin or the like.

According to this configuration, in addition to the same effects as in the above-described first embodiment, there is no need to provide a bobbin along the first coil as in the first embodiment, and the device is manufactured at low cost. The power loss of the electromagnetic wave due to the bobbin can be eliminated.

(Embodiment 5) FIG. 5 is a sectional view of an essential part of an antenna device according to a fifth embodiment of the present invention. The same reference numerals are used for the same components as those in the above-described first embodiment. And the description is omitted. In the figure, the bobbin 32 and the top plate 33 are integrally formed, and the adjustment knob 3
1 is configured to be slidable up and down in the center axis of the top plate 33 by rotating the top plate 1.

According to this configuration, the same effects as those of the above-described first embodiment can be obtained, and the bobbin 32 and the top plate 33 can be integrally formed.

(Embodiment 6) FIG. 6 is a sectional view of a main part of an antenna device according to a sixth embodiment of the present invention. The same reference numerals are used for the same components as those in the above-described fourth embodiment. And the description is omitted. 6 differs from the fourth embodiment in that the second coil 1 shown in FIG.
7 in that a rod-shaped conductor 34 is used instead of 7.

With this configuration, the same effect as that of the above-described fourth embodiment can be obtained, and an impedance characteristic different from that of the fourth embodiment can be provided. Range can be expanded.

(Embodiment 7) FIG. 7 is a sectional view of a main part of an antenna device according to a seventh embodiment of the present invention. In the figure, reference numeral 19 denotes a metal plug made of a conductive metal material, one end of which has a second contact 6 for connecting to an electronic circuit.
Is formed, and the insulating layer 20 is formed on the other end plane. A cylindrical bobbin 22 made of an insulating resin and having a thread groove 22a formed on a part of the inner peripheral surface thereof is formed on the insulating layer 20.
And a first coil 16 having an impedance characteristic corresponding to a desired first frequency is formed on an outer peripheral surface of the bobbin 22. One end of the first coil 16 is connected to at least a metal plug 19. It is electrically connected to one place. Next, a second coil 36 having an impedance characteristic corresponding to a desired second frequency is formed to have a diameter such that one of the coils 36 is rotatably engaged with the thread groove 22a of the bobbin 22, and the other is at least halfway. The coil is wound spirally for more than one turn. Thereby, the second coil 36 can move up and down along the thread groove 22a of the bobbin 22. After the adjustment, the second coil 3
In order to fix the position of the coil 6 at a desired position on the inner periphery of the bobbin 22, at least one portion where the inner periphery of the bobbin 22 contacts one end of the second coil 36 is fixed with resin or the like.

According to this configuration, the same effect as that of the above-described second embodiment can be obtained, and since there is no need to provide a top plate as compared with the second embodiment, it is possible to manufacture the device at low cost. Power loss of electromagnetic waves due to the top plate can be eliminated.

(Eighth Embodiment) FIG. 8 is a sectional view of a main part of an antenna device according to an eighth embodiment of the present invention. As shown in FIG. The top plate 41 and the third coil 40 are rotatably inserted into the inside 38.

With this configuration, the same effects as those of the second embodiment can be obtained, and three or more frequency bands can be provided by adding a coil.

(Embodiment 9) FIG. 9 is a sectional view of a main part of an antenna device according to a ninth embodiment of the present invention. As shown in FIG.
The structure is such that the insulating layer 20 is not formed on the upper surface of the metal plug 19.

According to this configuration, it is possible to have impedance characteristics and radiation characteristics different from those of the first embodiment.

[0048]

As described above, according to the present invention, the degree of coupling between the coils can be changed by changing the positional relationship of at least one coil constituting the antenna device. Frequency band, VS
The WR value can be easily changed, and the variation in the impedance characteristic can be easily corrected only by adjusting the WR value at the time of manufacturing the antenna.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an antenna device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part of an antenna device according to a second embodiment of the present invention;

FIG. 3 is a sectional view of a main part of an antenna device according to a third embodiment of the present invention;

FIG. 4 is a sectional view of a main part of an antenna device according to a fourth embodiment of the present invention;

FIG. 5 is a sectional view of a main part of an antenna device according to a fifth embodiment of the present invention.

FIG. 6 is a sectional view of a main part of an antenna device according to a sixth embodiment of the present invention.

FIG. 7 is a sectional view of a main part of an antenna device according to a seventh embodiment of the present invention;

FIG. 8 is a sectional view of a main part of an antenna device according to an eighth embodiment of the present invention.

FIG. 9 is a sectional view of a main part of an antenna device according to a ninth embodiment of the present invention;

FIG. 10 is a conceptual diagram of a whip antenna in a conventional mobile wireless device.

FIG. 11 is a detailed view of the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Whip antenna 2 Monopole antenna element 3 Antenna part 4 Insulating element 5 First contact 6 Second contact 7 Radio | wireless machine main body 8 Antenna matching circuit 9 Radio circuit 10 Feeding line 11 Feeding piece 12, 16 First coil 13 , 17, 36, second coil 14 case 15, 22, 32, 38 bobbin 18, 23, 26, 29, 33, 41 top plate 19 metal plug 20 insulating layer 21, 25, 28 antenna unit 27 sliding unit 31 adjustment Knob 34 Bar-shaped conductor 40 Third coil

 ──────────────────────────────────────────────────続 き Continued from the front page (72) Inventor Yoshio Koyanagi 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (17)

[Claims] 1. An antenna device corresponding to first and second frequency bands, wherein the first coil has impedance characteristics corresponding to the first frequency band, and is provided inside the first coil. Adjusting means for adjusting a positional relationship between the first coil and the second coil for obtaining a desired impedance characteristic, the adjusting means having a second coil having an impedance characteristic corresponding to a second frequency band; Characteristic antenna device. 2. The adjusting means comprises a cylindrical bobbin provided along the inside of the first coil, and a top plate slidably provided on the inner peripheral surface of the bobbin. 2. The coil according to claim 1, wherein one end of the coil is fixed to the top plate, and the second plate can be held at an arbitrary position in the first coil by sliding the top plate. Antenna device. 3. The adjusting means is provided along the inside of the first coil, and has a cylindrical bobbin having a thread groove on an inner peripheral surface thereof, and a disc-shaped top plate engaged with the thread groove. And fixing one end of the second coil to the top plate,
The second coil can be held at an arbitrary position in the first coil by rotating the top plate along a screw groove provided in the bobbin. Antenna device. 4. An end of the second coil is fixed to a sliding portion slidably provided on the inner peripheral surface of the top plate, and the second coil is slid by sliding the sliding portion. 4. A structure in which the first coil can be held at an arbitrary position in the first coil.
An antenna device according to item 1. 5. The adjusting means has a disk-shaped top plate provided so as to be engaged with a part of the first coil at an outer peripheral portion thereof, and adjusts the top plate along the first coil. The antenna device according to claim 1, wherein the second coil can be held at an arbitrary position in the first coil by rotating the antenna. 6. The antenna device according to claim 5, wherein the top plate is slid so as to obtain a desired impedance characteristic, and the top plate is fixed to the first coil. 7. The adjusting means comprises a cylindrical top plate fixed at least near one end of the first coil, and a sliding portion slidably provided on an inner peripheral surface of the top plate. The second coil can be held at an arbitrary position in the first coil by fixing one end of the second coil to the sliding portion and sliding the sliding portion. The antenna device according to claim 1. 8. A method in which a sliding portion slidably provided on an inner peripheral surface of the top plate is slid so that desired impedance characteristics are obtained, and the sliding portion is fixed to the top plate. The antenna device according to claim 4 or 7, wherein: 9. The antenna device according to claim 1, wherein the second coil is formed of a rod-shaped conductor. 10. An adjusting means provided along the inside of the first coil and having at least one of a cylindrical bobbin having a thread groove on an inner peripheral surface thereof and the second coil, the adjusting means comprising: The second coil can be held at any position in the first coil by rotating the engagement portion along the screw groove. The antenna device according to claim 1, wherein: 11. The antenna device according to claim 10, wherein the second coil is slid so that a desired impedance characteristic is obtained, and the second coil is fixed to the bobbin. 12. The antenna device according to claim 1, wherein the first frequency band is smaller than the second frequency band. 13. An antenna device corresponding to N (N is an integer of 3 or more) frequency bands, comprising: a first coil having impedance characteristics corresponding to a first frequency band; It has N-1 coils or rod-shaped conductors provided inside and having impedance characteristics corresponding to each frequency band other than the first frequency band, and at least one of the coils or rod-shaped conductors other than the first coil
An antenna device characterized in that one is movable inside the first coil. 14. The antenna device according to claim 13, wherein the top plate is slid so that desired impedance characteristics are obtained, and at least one of the top plates is fixed to the bobbin. 15. A second coil or rod-shaped member having at one end a terminal for electrically connecting to an electronic circuit and at the other end a metal plug electrically connected to one end of the first coil. 15. The antenna device according to claim 1, wherein one end of the conductor is electrically connected to the plug. 16. One end of a second coil having a terminal portion for electrically connecting to an electronic circuit at one end, and a metal plug electrically connected to one end of a first coil at the other end. 2. An insulating layer is provided on an upper surface of the metal plug so that the metal plug is not electrically connected to the metal plug.
6. The antenna device according to 5. 17. The antenna device according to claim 15, wherein the second coil contracts when one end of the second coil comes into contact with the metal plug.