WO2005101573A1

WO2005101573A1 - Mobile equipment antenna

Info

Publication number: WO2005101573A1
Application number: PCT/JP2005/003961
Authority: WO
Inventors: Akio Mamuro
Original assignee: Nippon Antena Kabushiki Kaisha
Priority date: 2004-04-12
Filing date: 2005-03-08
Publication date: 2005-10-27
Also published as: JP2005303655A

Abstract

A mobile equipment antenna having helical elements capable of providing double-resonance. The inside helical element (42b) is formed by folding back the tip of the outside helical element (42a) and reversely winding it in the outside helical element (42a). Power is supplied from an antenna holder (41) in contact with the lower end of the outside helical element (42a) to a helical antenna part (40) thus formed. Since the inside helical element (42b) is wound in the outside helical element (42a), the helical elements can be double-resonated.

Description

Specification

Mobile device antenna

Technical field

The present invention relates to a mobile device antenna provided in a mobile wireless device such as a mobile phone.

Background art

[0002] A mobile wireless device such as a mobile phone is provided with an antenna for transmitting and receiving calls and information. A common antenna for mobile devices is a retractable antenna that can be stored in the housing of a mobile phone so that it is easy to carry when waiting. In this case, when the whip element is stored in the housing, transmission and reception of the mobile phone become almost impossible. Therefore, even when the whip element is stored in the housing, the small helical element located outside the housing can be removed. It is provided at the tip of the whip element. Thus, when the whip element is stored in the housing, transmission and reception can be performed using this helicopter element.

[0003] Furthermore, it is also practiced to provide an antenna having only a helical element without a whip element in a housing of a mobile device. In the case of such an antenna, the helical element is small in size, and it can be used easily and can be used as a mobile device. FIG. 13 shows an example of a conventional configuration of such an antenna.

An antenna 100 shown in FIG. 13 is housed in a helical element 101 which is wound in a helical shape and has a small size, and a force-insulating antenna cover 102. A metal holder 103 is fitted to the lower end of the antenna cover 102, and power can be supplied to the helical element 101 from the holder 103. A screw is provided on the outer peripheral surface of the holder 103 so that the holder 103 can be screwed to a housing of the mobile device.

Disclosure of the invention

Problems to be solved by the invention

[0004] FIG. 14 shows a return loss frequency characteristic of the antenna 100 shown in FIG. Referring to the frequency characteristics of this return loss, the frequency at which the return loss increases at two frequencies It is a characteristic. Then, at the frequency of about 1.19 MHz indicated by mark 1, a return loss of about -5.7 dB is obtained, and it is almost in a resonance state. However, at the frequency of about 1.66MHz indicated by mark 2, the return loss was not obtained and only a force of about 1.66dB was obtained, which is not a resonance state. As described above, the conventional helical antenna has a problem that it is difficult to obtain a double resonance.

[0005] Therefore, an object of the present invention is to provide an antenna for a mobile device including a helical element capable of obtaining multiple resonance.

Means for solving the problem

[0006] In order to achieve the above object, an antenna for a mobile device of the present invention includes an outer helical element wound with a first diameter, and a first force smaller than the first diameter by bending one end of the outer helical element. The most important feature is to have a helical element consisting of an inner helical element which is wound in a reverse winding at a diameter of 2 and arranged inside the outer helical element.

The invention's effect

[0007] According to the present invention, the outer helical element wound with the first diameter and the one-sided force of the outer helical element are folded back and wound in reverse with a second diameter smaller than the first diameter, Since the inner helical element disposed inside the outer helical element and the helical element which acts as a force are provided, it is possible to provide a mobile station antenna capable of obtaining multiple resonances.

Brief Description of Drawings

FIG. 1 is a diagram showing an overall configuration of a mobile device antenna according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the overall configuration of a mobile device antenna according to a first embodiment of the present invention.

FIG. 3 is a perspective view showing an overall configuration of a mobile phone including a mobile station antenna according to the present invention.

FIG. 4 is a perspective view showing an antenna circuit of a mobile phone including the mobile device antenna according to the present invention. FIG. 5 is a perspective view showing an overall configuration of a mobile device antenna according to a second embodiment of the present invention.

FIG. 6 is a perspective view showing an overall configuration of a mobile device antenna according to a third embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a detailed configuration of a mobile station antenna according to a third embodiment of the present invention.

FIG. 8 is an exploded view of a mobile station antenna according to a third embodiment of the present invention.

FIG. 9 is a diagram showing a configuration in which an outer helical element in a mobile device antenna according to a third embodiment of the present invention is held by an antenna cover.

FIG. 10 is a diagram showing a configuration in which an inner helical element of an antenna for a mobile device according to a third embodiment of the present invention is held by an antenna bobbin.

FIG. 11 is a graph showing frequency characteristics of return loss when the winding pitch of the inner helical element is larger than the winding pitch of the outer helical element in the mobile station antenna according to the third embodiment of the present invention.

FIG. 12 is a graph showing frequency characteristics of return loss when the winding pitch of the inner helical element is set to be the same as the winding pitch of the outer helical element in the mobile station antenna according to the third embodiment of the present invention. .

FIG. 13 is a cross-sectional view showing an example of a configuration of a conventional mobile device antenna.

FIG. 14 is a graph showing frequency characteristics of return loss of a conventional mobile station antenna. Explanation of symbols

1 mobile phone, la housing, 2 mobile unit antenna, 3 circuit board, 4 mobile unit antenna, 5 mobile unit antenna, 10 helical antenna unit, 10a antenna cover, 11 wheel antenna unit, 11a whip element, l ib insulation tube, 12 top plug, 13 joint, 14 holder, 14a flange, 14b screw, 14c holding panel, 14d stopper, 15 holder nut, 16 contact terminal, 17 matching circuit, 18 high frequency circuit, 19 helical element , 30 Helical Antenna, 31 Whip Antenna, 32 Antenna Holder, 33 Joint, 33a Flange, 40 Helical Antenna, 40a Antenna Cano, Ink Storage, 41 Antenna Holder, 41 Screw, 41b Large Diameter, 42 Helical Element, 42a Outer helical element, 42b Inner helical element, 43 antenna nabobin, 100 antenna, 101 helicopter element, 102 antenna cover, 103 antenna

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] An object of the present invention is to provide an antenna for a mobile device including a helical element capable of obtaining a multiple resonance, and an outer helical element wound with a first diameter and one end force of the outer helical element. This is achieved by providing a helical element that is wound in a reverse direction with a second diameter smaller than the diameter of 1 and that acts as an inner helical element arranged inside the helical element outward.

FIG. 1 shows an overall configuration of a mobile device antenna according to a first embodiment of the present invention.

As shown in FIG. 1, a mobile station antenna 2 according to a first embodiment of the present invention includes a helical antenna section 10 and a whip antenna section 11, and the helical antenna section 10 and the whip antenna section 11 are insulated from each other. Are mechanically connected by a sex joint 13. The whip antenna section 11 is formed by covering a linear whip element with an insulating tube. The tip of the whip element is integrally formed and mechanically connected to the lower end of the joint 13 so as to be located substantially uniaxially.A conductive stopper is attached to the lower end of the whip element. Is fixed. Further, the whip antenna section 11 is slidably held by a conductive holder 14. The helical antenna section 10 is composed of an antenna cover for accommodating a helical element wound in two sections described later, and a conductive top plug 12 capable of supplying power to the helical element has a lower end of the helical antenna section 10. The force is arranged around the joint 13 to protrude.

Next, FIG. 2 is a cross-sectional view showing an overall configuration of a mobile device antenna 2 according to a first embodiment of the present invention.

As shown in FIG. 2, a lower portion of a whip element 1 la is integrally formed and fixed to a front end of the whip element 1 la when the resin joint 13 is formed. In this case, a deformed portion that is enlarged to prevent the whip element 11a made of, for example, a superelastic metal from coming out of the joint 13 is formed at the distal end portion. The whip element 11a is provided with an elastic insulating tube l ib made of synthetic resin. Has been coated. At the other end of the whip antenna section 11, a conductive stopper 14d having a diameter larger than that of the insulating tube 11b, for example, made of metal, is connected so as to be electrically connected to the whip element 11a. Has been fixed. Further, the holder 14 for holding the wobble antenna portion 11 so as to be able to expand and contract is inserted through the whip antenna portion 11 before fixing the stopper 14d. A through-hole formed in the holder 14 accommodates a holding panel 14c formed in a ring shape so that the holder 14 can securely hold the top plug 12 or the stopper 14d. Have been. A flange portion 14a is formed on the upper portion of the holder 14, and a screw portion 14b for attaching the holder 14 to the housing of the mobile device is formed to extend from below the flange portion 14a.

[0013] The antenna cover 10a of the helical antenna unit 10 is formed into a bag-like shape with an upper part closed by resin molding ABS resin, elastomer resin, or the like. A helical element 19 is housed inside the antenna cover 10a, and a conductive top plug 12 is fitted to a lower portion thereof. The helical element 19 is configured by winding an outer helical element and an inner helical element into two turns. The lower end of the outer helical element is fitted over and electrically connected to the upper part of the top plug 12, and the top plug 12 is integrally formed with an elongated and insulating joint 13! The upper part of the joint 13 is disposed in the antenna cover 10a so as to extend from the top plug 12 and hold the internal helical element.

In the mobile device antenna 2 configured as described above, the holder 114 made of, for example, metal is attached to a housing of a mobile phone or the like, and when the whip antenna unit 11 is extended with respect to the holder 14. As a result, the stopper 14d is inserted and held in the holder 14 with a downward force, and the lower end thereof comes into contact with the lower surface of the holder 14. As a result, the whip antenna section 11 is electrically connected to the holder 14, and only the whip antenna section 11 is in an operating state. When the whip antenna section 11 is stored in the housing, the whip antenna section 10 is inserted into the holder 14 from the joint 13 until the lower surface of the helical antenna section 10 contacts the upper surface of the holder 14, and is disposed around the joint 13. The conductive top plug 12 is inserted and electrically connected to the holder 14. As a result, only the spiral element 19 in the helical antenna unit 10 enters the operating state. [0015] Therefore, when the mobile device antenna 2 of the present invention is applied to a mobile phone, when the mobile device antenna 2 is extended, it is possible to efficiently transmit and receive using the whip antenna unit 11, If the antenna 2 for a machine is stored in a compact form, transmission and reception can be performed using the helical element 19 housed in the helical antenna unit 10. The mobile device antenna 2 is a multiple resonance antenna that operates in the first frequency band and the second frequency band.

This is because the whip antenna section 11 and the helical antenna section 10 are insulated by the joint 13 and used as an antenna. That is, when a capacitance is generated between the top plug 12 serving as the power supply means of the helical element 19 and the whip antenna section 11, the helical element 19 and the whip antenna section 11 are electrically coupled to each other. This will adversely affect the operation of the antenna. In order to prevent this, the insulating joint 13 is interposed so that the helical antenna section 10 and the whip antenna section 11 are sufficiently separated from each other to generate capacitance.

Next, FIG. 3 is a perspective view showing the entire configuration of a mobile phone provided with the mobile device antenna according to the present invention.

The mobile phone 1 shown in FIG. The mobile device antenna 2 is fixed to the housing la by screwing the holder 14 to a holder nut of the housing la. As described above, the whip antenna section 11 is slidably held by the holder 14, and when the whip antenna section 11 is extended with respect to the housing la as shown in the drawing, the whip antenna section 11 is in an operating state. It becomes. Also, when the whip antenna unit 11 is stored in the housing la, the helical antenna unit 10 is in an operating state.

Next, FIG. 4 is a perspective view showing an antenna circuit of a mobile phone provided with the mobile device antenna according to the present invention.

As shown in FIG. 4, the mobile device antenna 2 is fixed to the housing la by screwing the holder 14 to the holder nut 15. The holder nut 15 is fixed to the housing la so as to protrude into the housing la. In the housing la, an elastic contact terminal 16 is in contact with the holder nut 15. This contact terminal 16 is It is connected to the printed pattern formed on the circuit board 3. The printed pattern is provided with a matching circuit 17 as necessary, and is connected to a high-frequency circuit 18 provided on the circuit board 3. As a result, the mobile device antenna 2 is connected to the high-frequency circuit 18, and the transmission / reception circuit in the high-frequency circuit 18 can be transmitted and received using the mobile device antenna 2.

Next, FIG. 5 is a perspective view showing the overall configuration of a mobile device antenna according to a second embodiment of the present invention.

The mobile device antenna 4 shown in FIG. 5 has a helical antenna portion 30 provided with an antenna holder 32, and a whip antenna portion 31 provided slidably with respect to the helical antenna portion 30 and the antenna holder 32. I have. At the tip of the whip antenna section 31, an insulating elongated joint 33 is formed in a body, and at the tip of the joint 33, a disk-shaped flange 33a having a large diameter is formed. The helical element in which the outer helical element and the inner helical element are wound in two rows as shown in FIG. 2 is housed in the antenna cover constituting the helical antenna section 30. This mobile device antenna 4 is a multiple resonance antenna that operates in the first frequency band and the second frequency band.

In the mobile device antenna 4 configured as described above, the antenna holder 32 made of, for example, metal is attached to a housing of a mobile phone or the like, and the whip antenna unit 31 is extended with respect to the antenna holder 32. At this time, a stopper fixed to the lower end of the whip antenna unit 31 is inserted and held in the antenna holder 32 with a downward force, and the lower end comes into contact with the lower surface of the antenna holder 32. As a result, the whip antenna section 31 is electrically connected to the antenna holder 32, and the whip antenna section 31 is in an operating state. In this case, since the whip antenna section 31 is located within the helical antenna section 30, the helical antenna section 30 does not operate in a predetermined frequency band. When stored, the joint 33 is inserted into the helical antenna unit 30 and the antenna holder 32 until the lower surface of the flange 33a of the joint 33 contacts the upper surface of the helical antenna unit 30. As a result, the insulating joint 33 is located in the helical antenna section 30, and the helical antenna section 30 operates in a predetermined frequency band. In this case, Hui The antenna unit 31 does not operate because the connection with the antenna holder 32 is broken.

Next, FIG. 6 is a perspective view showing the entire configuration of a mobile station antenna according to a third embodiment of the present invention.

The mobile device antenna 5 shown in FIG. 6 includes a helical antenna unit 40. The helical element in which the outer helical element and the inner helical element are wound in two lines as shown in FIG. 2 is housed in the antenna cover constituting the helical antenna section 40. The mobile device antenna 5 is a multiple resonance antenna that operates in the first frequency band and the second frequency band.

Here, the helical element in which the outer helical element and the inner helical element, which are characteristic in the first to third embodiments of the present invention, are wound in two, is described in the third embodiment. An example will be described. FIG. 7 is a sectional view showing a detailed configuration of a mobile station antenna 5 according to a third embodiment of the present invention. FIG. 8 is an exploded view of the mobile station antenna 5 according to the third embodiment of the present invention. FIG.

As shown in these figures, the antenna cover 40a of the helical antenna portion 40 constituting the mobile device antenna 5 is formed by molding a resin such as ABS resin, elastomer resin, or the like into a bag whose upper part is closed. A helical element 42 in which an outer helical element 42a and an inner helical element 42b are wound in two rows is stored in a storage section 40b of the antenna cover 40a. An enlarged diameter portion 41b formed on the upper portion of the conductive antenna holder 41 is fitted to the lower portion of the antenna cover 40a, and the lower end of the outer helical element 42a is fitted on the upper portion of the antenna holder 41. I have. In addition, the antenna holder 41 holds an insulative elongated antenna bobbin 43, and the antenna bobbin 43 is disposed inside to hold the inner helical element 42b. Further, a screw portion 41 is formed on an outer peripheral surface at a lower portion of the antenna holder 41. By screwing the screw portion 41 to a holder nut fixed to a casing of a mobile phone or the like, the mobile device antenna 5 can be fixed to the mobile phone or the like.

As shown in the figure, the helical element 42 has an inner helical element 42b formed by folding the tip of the outer helical element 42a and winding it around the outer helical element 42a. That is, the winding diameter of the outer helical element 42a is It is larger than the winding diameter of the cull element 42b. Then, as shown in FIG. 9, the inner diameter of the antenna force bar 40a is slightly smaller than the outer diameter of the outer helical element 42a. Then, when the helical element 42 is stored in the storage portion 40b of the antenna cover 40a, the outer diameter of the outer helical element 42a is slightly reduced, and the outer circumference of the outer helical element 42a is formed inside the antenna cover 40a. Becomes sexually in contact with the peripheral surface. Thus, the outer helical element 42a can be prevented from changing in winding diameter by the antenna cover 40a, and its electrical characteristics can be stabilized. However, in FIG. 9, the inner helical element 42b is omitted from illustration.

As shown in FIG. 10, the outer diameter of the antenna bobbin 43 is substantially the same as the inner diameter of the inner helical element 42b. Then, when the helical element 42 is inserted into the antenna bobbin 43 fixed to the antenna holder 41, the antenna bobbin 43 is inserted into the inner helical element 42b without a gap. As a result, the inward recurrence 42b can be prevented from changing its winding diameter by the antenna bobbin 43, and its electrical characteristics can be stabilized. However, in FIG. 10, the outer helical element 42a is omitted from illustration.

The helical element 42 described above has the same configuration as the helical element 19 in the mobile station antenna 2 of the first embodiment shown in FIG. In this case, instead of the antenna bobbin 43, a joint 13 having a similar effect is provided in the inner helical element. Further, a helical element having the same configuration as the helical element 42 is also stored in the helical antenna section 30 of the mobile station antenna 4 of the second embodiment. In this case, when the helical element operates, a joint 33 having the same function as the antenna bobbin 43 is inserted into the inner helical element of the helical element.

FIG. 11 shows a return when the winding pitch of the inner helical element 42b is larger than the winding pitch of the outer helical element 42a in the mobile station antenna 5 according to the third embodiment of the present invention shown in FIG. 6 is a graph illustrating frequency characteristics of loss. Referring to this figure, the resonance state is shown at two frequencies. At the frequency of about 820 MHz indicated by mark 1, the return loss is about -11.8 dB, which is a good resonance state. Also Also, at the frequency of about 1460 MHz indicated by mark 2, the return loss is about –19.7 dB, indicating a good resonance state. The mobile device antenna 5 is installed almost at the center of a 300 × 300 mm ground plate, and the return loss characteristics are measured.

FIG. 12 shows a case where the winding pitch of the inner helical element 42b and the winding pitch of the outer helical element 42a are the same in the mobile station antenna 5 according to the third embodiment of the present invention shown in FIG. 6 is a graph showing the frequency characteristics of the return loss of FIG. Referring to this figure, the resonance state is shown at two frequencies. At the frequency of about 950MHz indicated by mark 1, the return loss is about -9.3dB, which is a good resonance state. Also, at the frequency of about 1440 MHz indicated by mark 2, the return loss is about -25.1 dB, indicating a good resonance state. The mobile device antenna 5 is installed almost at the center of a 300 × 300 mm ground plate, and the return loss characteristics are measured. As described above, in the mobile station antenna of the present invention, the resonance frequency becomes different by making the winding pitch of the inner helical element 42b the same as or larger than the winding pitch of the outer helical element 42a. By changing the relationship between the winding pitches of 42a and 42b, it becomes possible to adjust the resonance frequency of the multiple resonance.

In the mobile station antenna according to the present invention described above, the outer helical element of the helical element is fixed by the antenna cover, and the inner helical element is fixed by the antenna bobbin or the joint. With this structure, it is possible to prevent the inner and outer helical elements from coming into contact with each other. Then, the outer helical element and the inner helical element are reversely wound, and by changing the length, winding pitch, and thickness of each helical element, a double resonance can be realized and the desired resonance frequency can be reduced. So that you can get it. In addition, even if multiple resonances occur, the size of the mobile device antenna can be reduced. Furthermore, by winding the outer helical element and the inner helical element in two turns, it is possible to easily achieve multiple resonance matching by the helical antenna itself. Further, since the outer helical element and the inner helical element are reversely wound, the radiation of the inward helical element is not obstructed by the outer helical element, so that the operation is efficient.

Industrial applicability In the above description, an antenna for a mobile device is used. However, the present invention is not limited to this, and can be applied to a general helical antenna that wants to perform double resonance.

Claims

The scope of the claims

[1] An outer helical element wound with a first diameter, and an outer helical element that is turned back from one end of the outer helical element and wound in a reverse winding with a second diameter smaller than the first diameter, and the outer helical element is returned to the outer helical element. Helical element consisting of an inner helical element placed inside the

An insulating antenna cover in which the helical element is housed in a housing formed therein, and an open lower end of the outer helical element where the outer peripheral surface is in contact with the inner peripheral surface;

An insulated antenna bobbin disposed in the antenna cover, wherein an inner peripheral surface of the inner helical element contacts an outer peripheral surface;

A conductive antenna holder fitted into the opening at the lower end of the antenna cover, holding the antenna bobbin, and capable of supplying power to the other end of the outer helical element;

An antenna for a mobile device, comprising:

[2] An outer helical element wound with a first diameter, and an outer helical element folded back from one end of the outer helical element and wound in a reverse winding with a second diameter smaller than the first diameter, and the outer helical element is wound around the outer helical element. Helical element consisting of an inner helical element placed inside the

An insulating antenna cover in which the helical element is stored in a storage portion formed therein, and an outer end of the outer helical element is in contact with an inner peripheral surface, and an open lower end is provided;

An insulating joint having an upper portion disposed in the antenna cover and an inner peripheral surface of the inner helical element being in contact with an outer peripheral surface;

A conductive top plug fitted into the opening at the lower end of the antenna cover, the lower part of the joint penetrating substantially along the central axis, and capable of supplying power to the other end of the outer helical element; ,

A whip element fixed to the lower end of the joint,

A holder for slidably holding the whip element, An antenna for a mobile device, comprising: