JPH10242740A - Multi-resonance antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use the antenna for two frequency bands or over apart from each other. SOLUTION: An upper end of a straight line whip antenna element 2 is inserted to a lower end of a parasitic antenna coil element 1, then the whip antenna element 2 and the parasitic antenna element 1 are insulated but coupled electromagnetically. A signal source 5 is connected to the lower end of the whip antenna element 2 to energize it, then the antenna is resonated at two frequency bands apart from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable telephone and a simplified portable telephone system (PHS: personal handyphone system).
The present invention relates to a multi-resonant antenna that can be used in frequency bands separated from each other used in the above-mentioned method.

[0002]

2. Description of the Related Art In general, a portable telephone is provided with a telescopic antenna which can be extended from a housing at the time of use and can be stored in the housing at the time of standby. Note that, even when the antenna is housed in the housing, the antenna is configured such that the helical antenna element always projects from the housing so that transmission and reception are possible. The structure of such an antenna will be briefly described. Generally, the antenna is composed of a whip antenna element and a helical antenna element integrally provided at the upper end of the whip antenna element. When the antenna is extended, power is supplied to the whip antenna element, and when the antenna is stored, power is supplied to the helical antenna element.

In a PHS machine, a helical antenna element is fixed to a housing and provided so as to protrude from the housing. The reason why the helical antenna element is used is that the entire length is shortened and the handling becomes easy. Note that the frequency band of the mobile phone is 800 MHz.
Band and 1500 MHz band are assigned,
In S, the 1900 MHz band is assigned.

[0004]

However, since the frequency band that can be used by the antenna is narrow, it is necessary to prepare an antenna for each device that uses a different frequency band. Further, when the device supports a plurality of frequency bands, it is necessary to exchange antennas for each frequency band to be used. Therefore, an object of the present invention is to provide a multi-resonant antenna that can be used in both frequency bands even in frequency bands separated from each other such as a mobile phone and a PHS.

[0005]

In order to achieve the above object, a first multi-resonant antenna according to the present invention comprises a first antenna element having one end serving as a feeding point, and an electromagnetic force applied to the first antenna element. A first antenna element and a coil-shaped second antenna element fitted to the first antenna element so as to resonate in two separated frequency bands. In such a first multi-resonant antenna of the present invention,
The first antenna element is formed of a linear wire, and is formed in a groove formed on the outer peripheral surface of an insulating cylinder in which the lower end is inserted into the upper end of the first antenna element. Then, the second antenna element may be formed.

A second multi-resonant antenna according to the present invention comprises:
Two separate frequencies consisting of a coiled second antenna element fitted to the first antenna element so as to electromagnetically couple to a linear first antenna element having one end serving as a feed point A first antenna that resonates in a band, a coil-shaped third antenna element that is electrically insulated and disposed so as to be integrated in the extension direction of the first antenna, and has one end serving as a feeding point; A second antenna resonating in the two separated frequency bands, comprising a coil-shaped fourth antenna element fitted to the third antenna element so as to be electromagnetically coupled to the third antenna element; And a multi-resonant antenna including an antenna, when the multi-resonant antenna is extended from the mounting body, power is supplied only to the first antenna, and the multi-resonant antenna is housed in the mounting body. Sometimes the second It is to be powered only antenna.

In the above-described second multi-resonant antenna of the present invention, the first antenna element is formed of a linear wire, and the lower end of the first antenna element is fitted to the upper end of the first antenna element. The second antenna element is formed in a helical groove formed on the outer peripheral surface of the inserted first insulating cylinder, and the third antenna element is connected to the second antenna element.
Of the third insulating cylinder, which is formed in a helical groove formed on the outer peripheral surface of the insulating cylinder, and whose lower end is inserted into the upper end of the second insulating cylinder. The fourth antenna element is formed in a helical groove formed on the outer peripheral surface, and a conductive stopper fixed to a lower end of the first antenna element is used to supply power to the first antenna. A conductive top whose lower end is fitted to the upper end of the first insulating cylinder and whose upper end is fitted to the lower end of the second insulating cylinder. A plug may be a feeding point of the second antenna.

Further, the third multi-resonant antenna of the present invention is fitted to the first antenna element so as to be electromagnetically coupled to the linear first antenna element having one end serving as a feeding point. A first antenna that resonates in two separate frequency bands composed of a coiled second antenna element, and an electrically insulated so that the first antenna can slide inside the first antenna; And a coil-shaped fourth antenna element fitted to the third antenna element so as to be electromagnetically coupled to the third antenna element. And a second antenna resonating in the two separated frequency bands, wherein the multi-resonant antenna is fed to the first antenna when the multi-resonant antenna is extended from the mounting body. At the same time When the vibration antenna is accommodated in the mounting member, which is to be powered only in the second antenna.

Still further, the fourth multi-resonant antenna of the present invention includes a first antenna element having one end serving as a feed point, and the first multi-resonant antenna being electromagnetically coupled to the first antenna element. By providing a coil-shaped second antenna element fitted to the antenna element, and further comprising a coil-shaped third antenna element fitted to the second antenna element,
It is designed to resonate in multiple frequency bands separated from each other.

According to the present invention, since a multi-resonant antenna capable of resonating in a plurality of frequency bands can be provided, a device in a communication system having a different system such as a cellular phone or a PHS can be used as an antenna. Can be used without any change in the configuration. Therefore, the cost of the antenna alone can be reduced. Further, in a device corresponding to a plurality of communication systems, by providing one multi-resonance antenna according to the present invention, communication in a plurality of systems can be enabled. Note that this multi-resonant antenna has an 800 MHz band, a 1500 MHz band, and a 1900 MHz band.
Not only can it be used in the MHz band, but it is also possible to resonate in various frequency bands by adjusting the length of the whip antenna element 2 and the parasitic antenna element 1 and the degree of coupling between them.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 are schematic views of a first embodiment of a multi-resonant antenna according to the present invention. In FIG. 1, reference numeral 1 denotes a parasitic antenna element formed in a coil shape, and reference numeral 2 denotes a linear whip antenna element.
The lower end of the parasitic antenna element 1 is fitted to the upper end of the whip antenna element 2 so that the whip antenna element 2 and the parasitic antenna element 1 are insulated and electromagnetically coupled. Then, the lower end of the whip antenna element 2 is set as a feeding point, and the signal source 5 is connected, so that the whip antenna element 2 and the parasitic antenna element 1 are brought into an operating state. Note that the diameter of the parasitic antenna element 1 is φ1, the length thereof is l1, and the whip antenna element 2 is
When the length is L1, the diameter φ1 is selected such that the circumference length πφ1 of the parasitic antenna element 1 is extremely small with respect to the used wavelength λ. When the multi-resonant antenna is set to the high impedance operation mode, the whip antenna element 2 is excited by the signal source 5 via the matching circuit 6 shown.

Next, the multi-resonant antenna shown in FIG. 2 includes a helical antenna element 4 formed in a coil shape and a parasitic antenna element 3 formed in a coil shape with a diameter larger than the diameter of the helical antenna element 4. It is configured. The lower end of the parasitic antenna element 3 is fitted to the upper end of the helical antenna element 4 so that the helical antenna element 4 and the parasitic antenna element 3 are insulated and electromagnetically coupled. ing. Note that the lower end of the helical antenna element 4 is a feeding point, and the signal source 5 is connected. Note that the diameter of the parasitic antenna element 3 is φ
2. When the length is l2 and the length of the helical antenna element 4 is L2, the circumferential length πφ of the parasitic antenna element 3
2, and the circumference length πφ3 of the helical antenna element 3
However, the diameters φ2 and φ3 are selected so as to be extremely small with respect to the used wavelength λ.

When the multi-resonant antenna is set to the high impedance operation mode, the helical antenna element 4 is excited by the signal source 5 via the matching circuit 6 shown. The winding direction of the helical antenna element 4 and the winding direction of the parasitic antenna element 3 may be the same or opposite. Further, the relationship between the length L1 of the whip antenna element 2 and the length L2 of the helical antenna element 4 and the high frequency band f1 and the low frequency band f2 in the used frequency band shown in FIG. L1, L2
<1/4 wavelength of f2. Thus, the whip antenna element 2 and the helical antenna element 4 are generally １ ／
This is a λ mode antenna.

In the multi-resonant antenna shown in FIG.
The resonance frequency of the whip antenna element 2 alone in the 4λ mode is about 1400 MHz, the degree of coupling of the parasitic antenna element 1 electromagnetically coupled to the whip antenna element 2, and the length of the parasitic antenna element 1 Is adjusted, the resonance characteristics are exhibited in the 800 MHz band and the 1900 MHz band as shown in FIG.
In the multi-resonant antenna shown in FIG. 2, the resonance frequency of the helical antenna element 4 in the 1 / 4.lamda. Mode is about 1200 MHz, and the parasitic antenna element 3 electromagnetically coupled to the helical antenna element 4 is used. 14 and the length of the parasitic antenna element 3, the 800 MHz band and the 1900 M
Resonance characteristics are exhibited in the Hz band.

Therefore, by using the multi-resonant antenna shown in FIGS. 1 and 2, a portable communication device capable of transmitting and receiving in, for example, the 800 MHz band and the 1900 MHz band can be realized. The multi-resonant antenna of the present invention can be used not only in the 800 MHz band and the 1900 MHz band, but also in the length of the whip antenna element 2, the helical antenna element 4, the parasitic antenna elements 1 and 3, and the distance between the antenna elements. By adjusting the degree of coupling, it is possible to resonate in various frequency bands.

Next, FIGS. 3 and 4 show a specific configuration when the multi-resonant antenna according to the first embodiment of the present invention shown in FIG. 1 is applied to a vehicle-mounted antenna. FIG. 3 shows a state in which the multi-resonant antenna according to the present invention is mounted on a roof of a vehicle body. In this figure, a multi-resonant antenna 10 is a roof 10
A cable 12 which is attached to the center of the cable 0 by an attachment portion 11 and is connected to a feed point of the multi-resonant antenna 10 is drawn into the vehicle body. The detailed configuration of such a multi-resonant antenna 10 is shown in FIGS. FIG. 4A shows the appearance of the multi-resonant antenna 10, and the outer surface of the multi-resonant antenna 10 has an FRP (fiber rein
The antenna is covered with an antenna cover 13 made of, for example, forced plastic), and a mounting portion 11 is fixed to a lower end thereof. The mounting portion 11 has a built-in magnet and can be fixed to the roof 100, or can be fixed to the roof 100 or the trunk lid with double-sided tape or a trunk lid fitting. A cable 1 for feeding power to the multi-resonant antenna 10 built in the antenna cover 13
2 is pulled out from the lower end.

FIG. 4B shows the internal configuration of the multi-resonant antenna 10 covered by the antenna cover 13, and FIG. 4C shows a half-sectional view of the multi-resonant antenna 10. As shown in these figures, a lower end of a resin-made insulating cylinder 20 is fitted into an upper end of a rod-shaped whip antenna element 2. A helical groove is formed on the outer peripheral surface of the insulating cylinder 20, and a conductor is formed in the groove by plating or vapor deposition. As a result, the parasitic antenna element 1 is formed on the outer peripheral surface of the insulating cylinder 20. As described above, the whip antenna element 2 and the parasitic antenna element 1 are arranged so as to be insulated and electromagnetically coupled. The core wire of the coaxial cable 12 is connected to the lower end of the whip antenna element 2. In addition, the parasitic antenna element 1 is
0 may be constituted by a coil wound helically on the outer peripheral surface.

In the multi-resonant antenna according to the first embodiment of the present invention shown in FIG. 4, the whip antenna element 2 is electromagnetically coupled to the parasitic antenna element 1. By adjusting the length of the antenna element 2 and the length of the parasitic antenna element 1, resonance characteristics are exhibited in the 800 MHz band and the 1900 MHz band as shown in FIG. Therefore, it can be used for any device without changing the configuration in the frequency band of the mobile phone or the frequency band of the PHS which are allocated apart from each other.

Next, a schematic configuration diagram of a second embodiment of a multi-resonant antenna of the present invention suitable for application to a portable device is shown in FIG.
And FIG. The multi-resonant antenna according to the second embodiment includes a first multi-resonant antenna and a second multi-resonant antenna. However, FIG. 5 is a diagram illustrating a state where the multi-resonant antenna according to the second embodiment is extended, and FIG. 6 is a diagram illustrating a state where the multi-resonant antenna according to the second embodiment is housed. 5 and 6, reference numeral 1 denotes a coil-shaped first parasitic antenna element which is activated when the multi-resonant antenna is extended, and 2 is a linear antenna which is activated when the multi-resonant antenna is extended. The first multi-resonant antenna is constituted by the first parasitic antenna element 1 and the whip antenna element 2. The lower end of the first parasitic antenna element 1 is fitted to the upper end of the whip antenna element 2 so that the whip antenna element 2 and the first parasitic antenna element 1 are insulated and electromagnetically coupled. Have been. When the multi-resonance antenna is extended, the signal source 5 is connected to a feed point at the lower end of the whip antenna element 2 as shown in FIG.

At this time, when the first multi-resonant antenna including the first parasitic antenna element 1 and the whip antenna element 2 is set to the high impedance operation mode, impedance matching with the signal source 5 is performed. Then, the whip antenna element 2 is excited by the signal source 5 via the matching circuit 6 shown. Reference numeral 4 denotes a coil-shaped helical antenna element that is activated when the multi-resonant antenna is housed, and 3 has a diameter larger than the diameter of the helical antenna element 4 that is activated when the multi-resonant antenna is housed. This is a second parasitic antenna element formed in a coil shape, and the helical antenna element 4 and the parasitic antenna element 3 constitute a second multi-resonant antenna. The lower end of the second parasitic antenna element 3 is fitted to the upper end of the helical antenna element 4, so that the helical antenna element 4 and the second parasitic antenna element 3 are insulated and electromagnetically. Is joined to. When the multi-resonance antenna is housed, the signal source 5 is connected to the feed point at the lower end of the helical antenna element 4 as shown in FIG.

At this time, the helical antenna element 4 and the second
When the second multi-resonant antenna composed of the parasitic antenna element 3 is set to the high impedance operation mode, the helical antenna element 4 is connected via the matching circuit 6 shown in FIG. The signal source 5 is connected to the lower end of the. The winding direction of the helical antenna element 4 and the winding direction of the second parasitic antenna element 3 may be the same or opposite. 5 and 6, a first multi-resonant antenna including the whip antenna element 2 and the first parasitic antenna element 2, and a second multi-resonant antenna including the helical antenna element 4 and the second parasitic antenna element 3. The antenna is arranged on a straight line and integrated with the antenna.
In this case, the second multi-resonant antenna is arranged on the first multi-resonant antenna.

Next, a schematic configuration diagram of a third embodiment of the multi-resonant antenna of the present invention, which is preferably applied to a portable device, is shown in FIG.
And FIG. The multi-resonant antenna according to the third embodiment has a configuration in which the first multi-resonant antenna is slidable in the second multi-resonant antenna as compared with the multi-resonant antenna according to the second embodiment. , And is the same in other configurations. FIG. 7 is a diagram illustrating a state where the first multi-resonant antenna is extended in the multi-resonant antenna according to the third embodiment. FIG. 8 is a diagram illustrating the first multi-resonant antenna according to the third embodiment. It is a figure showing the state where a resonance antenna was stored.

In FIGS. 7 and 8, reference numeral 1 denotes a first parasitic antenna element formed into a coil which is brought into an operating state when the first multi-resonant antenna is extended, and 2 denotes a first parasitic antenna element when the first multi-resonant antenna is extended. The first whip antenna element 1 and the whip antenna element 2 constitute a first multi-resonant antenna. The lower end of the first parasitic antenna element 1 is fitted to the upper end of the whip antenna element 2 so that the whip antenna element 2 and the first parasitic antenna element 1 are insulated and electromagnetically coupled. Have been. When the multi-resonance antenna is extended, the signal source 5 is connected to the feed point at the lower end of the whip antenna element 2 as shown in FIG. At the same time, a second multi-resonant antenna composed of the helical antenna element 4 and the second parasitic antenna element 3 is also connected to the signal source 5. At this time, when the first multi-resonant antenna and the second multi-resonant antenna are set to a high impedance operation mode, a whip antenna is connected via a matching circuit 6 shown in FIG. The element 2 and the helical antenna element 4 are excited by the signal source 5.

In the second multi-resonant antenna, reference numeral 4 denotes a helical antenna element formed in a coil shape, and reference numeral 3 denotes a second parasitic antenna element formed in a coil shape with a diameter larger than the diameter of the helical antenna element 4. And the second by the helical antenna element 4 and the parasitic antenna element 3.
A multi-resonant antenna is configured. The lower end of the second parasitic antenna element 3 is fitted to the upper end of the helical antenna element 4 so that the helical antenna element 4 and the second
The parasitic antenna element 3 is insulated and electromagnetically coupled. Regardless of whether or not the first multi-resonant antenna is housed, the signal source 5 is connected to the feed point at the lower end of the helical antenna element 4 as shown in FIGS. When the first multi-resonant antenna is housed, power is supplied only to the second multi-resonant antenna.

At this time, when the first multi-resonant antenna composed of the first parasitic antenna element 1 and the whip antenna element 2 is set to the high impedance operation mode, impedance matching with the signal source 5 is performed. Then, the whip antenna element 2 is excited by the signal source 5 via the matching circuit 6 shown. The winding direction of the helical antenna element 4 and the winding direction of the second parasitic antenna element 3 may be the same or opposite. As shown in FIGS. 7 and 8, the first multi-resonant antenna including the whip antenna element 2 and the first parasitic antenna element 1 is a second multi-resonant antenna including the helical antenna element 4 and the second parasitic antenna element 3. The antenna is slidably arranged in the antenna.
In this case, the second multi-resonance antenna is attached so as to be fixed to the housing of the device.

Next, a specific configuration of the multi-resonant antenna according to the second embodiment, which is preferably applied to the portable device shown in FIGS. 5 and 6, is shown in FIGS. However, FIG. 9 is an external view of the multi-resonant antenna, and FIG.
FIG. 11A shows a state in which the multi-resonant antenna according to the second embodiment is extended with respect to the housing of the portable device, and FIG. 3 shows a state in which the multi-resonant antenna of the embodiment is housed. Hereinafter, a specific configuration of the multi-resonant antenna according to the second embodiment will be described with reference to these drawings. In the multi-resonant antenna of the second embodiment, as shown in FIGS. 9 and 10, a top 31 made of a resin such as ABS or elastomer is fixed to the tip, and a conductive top plug 32 is formed below the top. Have been. The top 31 has a cylindrical shape, and has a second multi-resonant antenna built therein.

That is, the helical antenna element 4 and the second parasitic antenna element 3 are built inside the top 31, and the helical antenna element 4 and the second parasitic antenna element 3 form a second multi-resonant antenna. It is configured.
The helical antenna element 4 is formed on the outer peripheral surface of the second insulating cylinder 41 made of resin. A helical groove is formed on the outer peripheral surface of the insulating cylinder 41, and a conductor serving as the helical antenna element 4 is formed in the groove by vapor deposition or plating. A third insulating cylinder 40 is fitted at the upper end of the second insulating cylinder 41, and a second parasitic antenna element 3 is formed on the outer peripheral surface of the third insulating cylinder 40. In this case, a helical groove is formed on the outer peripheral surface of the third insulating cylinder 40, and a conductor serving as the second parasitic antenna element 3 is formed in the groove by vapor deposition or plating. Thereby, the helical antenna element 4 and the second parasitic antenna element 3 are insulated, and
It becomes electromagnetically coupled.

The lower end of the second insulating cylinder 41 is fitted to the conductive top plug 32, so that the helical antenna element 4 formed on the outer peripheral surface of the second insulating cylinder 4 is formed.
And the top plug 32 are electrically connected. In the top plug 32, an insertion hole formed from the lower end is formed halfway, and the distal end of the first insulating cylinder 42 is fitted and fixed in the insertion hole. This first
The first parasitic antenna element 1 is formed on the outer peripheral surface of the insulating cylinder 42. In this case, a helical groove is formed on the outer peripheral surface of the first insulating cylinder 42, and the first
A conductor serving as the parasitic antenna element 1 is formed by vapor deposition or plating.

Further, the tip of the rod-shaped whip antenna element 2 is fitted into the lower end of the first insulating cylinder 42. Thereby, the whip antenna element 2 and the first parasitic antenna element 1 are insulated and electromagnetically coupled. A conductive stopper 35 is fixed to the lower end of the whip antenna element 2. Further, the outer periphery of the first multi-resonant antenna including the whip antenna element 2 and the first parasitic antenna element 1 is covered with a covering tube 3.
3 is covered.

Further, a conductive holder 34 is slidably fitted into the covering tube 33 and the top plug 32. The holder 34 is a portion that is fixed to the housing when the multi-resonance antenna is fixed to the housing of a portable device or the like. When the stopper 35 is fitted into the holder 34, the first multi-resonant antenna is electrically connected to the stopper 35 to excite it, and when the top plug 32 is fitted into the holder 34, The second multi-resonant antenna is excited by being electrically connected to the plug 32. The first parasitic antenna is formed by winding a conductive wire in a helical groove formed on the outer peripheral surface of the first insulating cylinder 42, the second insulating cylinder 41, and the third insulating cylinder 40. The element 1, the helical antenna element 4, and the second parasitic antenna element 3 may be formed.

Next, an operation state when the multi-resonant antenna according to the second embodiment shown in FIGS. 9 and 10 is attached to a housing of a portable device or the like will be described with reference to FIG. FIG. 11A shows a state where the multi-resonant antenna is extended from the housing 50. This multi-resonant antenna is
Is fitted into an insertion hole formed in the housing 34, and a screw portion 51 is screwed from a lower end side of the holder 34 to be attached to the housing 50. As shown in the figure, when the multi-resonant antenna is extended, the stopper 35 provided at the lower end of the multi-resonant antenna is fitted into the holder 34. Thereby, power is supplied from the signal source 5 to the whip antenna element 2 via the holder 34. Further, the first parasitic antenna element 1 is also fed with power via the whip antenna element 2.

At this time, when the first multi-resonant antenna including the first parasitic antenna element 1 and the whip antenna element 2 is set to the high impedance operation mode, the impedance matching with the signal source 5 is performed. Then, the whip antenna element 2 is excited by the signal source 5 via the matching circuit 6 shown. When the multi-resonant antenna is extended, power is not supplied to the second multi-resonant antenna including the helical antenna element 4 and the second parasitic antenna element 3, so that the second multi-resonant antenna does not operate.

FIG. 11B shows a case where the multi-resonant antenna is mounted on the housing 50.
2 shows a state in which it is stored inside. As shown, when the multi-resonant antenna is housed, the top 31
The top plug 32 fixed under the
Will be fitted inside. Thereby, the holder 34
Is supplied from the signal source 5 to the helical antenna element 4 via the. Further, power is also supplied to the second parasitic antenna element 3 via the helical antenna element 4. At this time, if the second multi-resonant antenna composed of the second parasitic antenna element 3 and the helical antenna element 4 is set to a high impedance operation mode, it is shown in FIG. Matching circuit 6
, The whip antenna element 2 is excited by the signal source 5. When the multi-resonant antenna is housed, no power is supplied to the first multi-resonant antenna including the whip antenna element 2 and the first parasitic antenna element 1, so that the first multi-resonant antenna does not operate.

When the multi-resonant antenna is extended as shown in FIG.
Is electromagnetically coupled to the first parasitic antenna element 1. By adjusting the degree of coupling, the length of the whip antenna element 2, and the length of the first parasitic antenna element 1, FIG. 800MHz band and 1900 as shown
In the MHz band, resonance characteristics are exhibited. When a multi-resonant antenna is housed as shown in FIG. 11B, the helical antenna element 4 is electromagnetically coupled to the second parasitic antenna element 3. By adjusting the length of the element 4 and the length of the second parasitic antenna element 3, as shown in FIG.
Resonance characteristics are exhibited in the 0 MHz band and the 1900 MHz band.

Therefore, by using the multi-resonant antenna according to the second embodiment of the present invention shown in FIGS. 10 and 11, it is possible to realize a portable communication device capable of transmitting and receiving in the 800 MHz band and the 1900 MHz band, for example. it can. The multi-resonant antenna according to the second embodiment of the present invention can be used not only in the 800 MHz band and the 1900 MHz band, but also in the whip antenna element 2, the helical antenna element 4, and the first parasitic antenna element 1. By adjusting the length and the degree of coupling of the second parasitic antenna element 3, it is possible to resonate in various frequency bands.

Next, a schematic configuration of a multi-resonant antenna according to a fourth embodiment of the present invention is shown in FIGS. 4th
The multi-resonant antenna according to the embodiment is a multi-resonant antenna that can resonate in three or more frequency bands. In the multi-resonant antenna according to the fourth embodiment shown in FIG. 12A, 1 is a first parasitic antenna element formed in a coil shape, 2 is a linear whip antenna element, and 7 is a whip antenna element. This is a third parasitic antenna element formed in a coil shape. The lower end of the first parasitic antenna element 1 is
The whip antenna element 2 and the first parasitic antenna element 1 are fitted to the upper end of the whip antenna element 2 so as to be insulated and electromagnetically coupled. Further, the lower end of the third parasitic antenna element 7 is fitted on the upper end of the first parasitic antenna element 1 so that the first parasitic antenna element 1 and the third parasitic antenna element 7 are insulated. And are electromagnetically coupled. In addition, the lower end of the whip antenna element 2 is used as a feeding point, and the signal source 5 is connected.

When the multi-resonant antenna is set to a high impedance operation mode, the whip antenna element 2 is excited by the signal source 5 via the matching circuit 6 shown. The first parasitic antenna element 1
And the winding direction of the third parasitic antenna element 7 may be the same or opposite. The diameter of the first parasitic antenna element 1 is φ1, its length is 11, the length of the whip antenna element 2 is L1, and the third parasitic antenna element 7 is
Is the diameter of φ4 and its length is 111, the circumference length πφ1 of the first parasitic antenna element 1 and the circumference length πφ4 of the third parasitic antenna element 7 are extremely different with respect to the used wavelength λ. The diameter φ1 and the diameter φ4 are selected so as to be small.

Next, in a modification of the multi-resonant antenna according to the fourth embodiment shown in FIG. 12B, a helical antenna element 4 formed in a coil shape and a coil having a diameter larger than the diameter of the helical antenna element 4 are used. The antenna includes a second parasitic antenna element 3 formed in the shape of a circle, and a fourth parasitic antenna element 8 formed in a coil shape with a diameter larger than the diameter of the second parasitic antenna element 3. The lower end of the fourth parasitic antenna element 8 is fitted to the upper end of the second parasitic antenna element 3 to insulate the fourth parasitic antenna element 8 from the second parasitic antenna element 3. And are electromagnetically coupled. Further, the lower end of the second parasitic antenna element 3 is fitted to the upper end of the helical antenna element 4, so that the helical antenna element 4 and the parasitic antenna element 3 are insulated.
Electromagnetically coupled.

The signal source 5 is connected to the lower end of the helical antenna element 4 as a feeding point. When the multi-resonant antenna is set to a high impedance operation mode, the helical antenna element 4 is excited by the signal source 5 via the matching circuit 6 shown. Furthermore, the winding direction of the helical antenna element 4, the winding direction of the second parasitic antenna element 3, and the winding direction of the fourth parasitic antenna element 8 may be the same or opposite. Furthermore, the diameter of the second parasitic antenna element 3 is φ2, its length is l2, and the diameter of the fourth parasitic antenna element 8 is φ2.
5, when its length is 122, the diameter of the helical antenna element 4 is φ3, and its length is L2, the circumference length πφ2 of the second parasitic antenna element 3 and the circle of the fourth parasitic antenna element 8 The diameters φ2, φ5, and φ3 are selected so that the circumference length πφ5 and the circumference length πφ3 of the helical antenna element are extremely small with respect to the used wavelength λ.

In the multi-resonant antenna according to the fourth embodiment shown in FIG. 12A, the length L1 of the whip antenna element 2 and the length l1 of the first parasitic antenna element 1 are shown in FIG. The degree of electromagnetic coupling between the whip antenna element 2, the first parasitic antenna element 1, and the third parasitic antenna element 7, and the length of the third parasitic element 7 are adjusted to have the same dimensions as the antenna. Thus, as shown in FIG. 15, 800 MHz band, 1000 MHz band, 1600 MHZ
Resonance characteristics are exhibited in the z band and the 1900 MHz band.

In the multi-resonant antenna according to the fourth embodiment shown in FIG. 12B, the length L2 of the helical antenna element 4 and the length l2 of the second parasitic antenna element 3 are shown in FIG. The degree of electromagnetic coupling between the helical antenna element 4, the second parasitic antenna element 3, and the fourth parasitic antenna element 8 and the length of the fourth parasitic antenna element 8 are adjusted to have the same dimensions as the multi-resonant antenna. By doing so, resonance characteristics similar to the resonance characteristics shown in FIG. 15 can be obtained.

Therefore, by using the multi-resonant antenna of the fourth embodiment shown in FIGS. 12A and 12B, a portable communication device capable of transmitting and receiving in a multi-frequency band can be realized. . The multi-resonant antenna according to the fourth embodiment of the present invention includes a whip antenna element 2, a helical antenna element 4, and first to fourth parasitic antenna elements.
By adjusting the length of the parasitic antenna element 8 and the degree of coupling, resonance can be achieved in various frequency bands.

Here, an example of a method of forming an antenna element on the outer periphery of an insulating cylinder as shown in FIGS. 4 and 9 to 11 will be described. First, a helical groove is formed on the outer periphery of the insulating cylinder. Then, a conductive layer is formed on the entire surface of the insulating cylinder by vapor deposition or plating. Next, when the outer peripheral surface of the insulating cylinder is cut,
The conductive layer is removed leaving the conductive layer formed in the groove formed on the outer peripheral surface. Thus, a coil-shaped antenna element can be formed on the outer peripheral surface of the insulating cylinder.

[0044]

Since the present invention is configured as described above, it can be a multi-resonant antenna capable of resonating in a plurality of frequency bands, and can be used in different communication systems such as a cellular phone and a PHS. It can be used for devices in the system without any change in configuration.
Therefore, the cost of the antenna alone can be reduced. Further, in a device corresponding to a plurality of communication systems, by providing one multi-resonance antenna according to the present invention, communication in a plurality of systems can be enabled. Note that this multi-resonant antenna has an 800 MHz band, a 1500 MHz band, and a 1900 MHz band.
Not only can it be used in the MHz band, but it is possible to resonate in various frequency bands by adjusting the length of the whip antenna element 2 and the parasitic antenna element 1 and the degree of coupling between them.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of a multi-resonant antenna according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a schematic configuration of a modified example of the multi-resonant antenna according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a configuration when the multi-resonant antenna according to the first embodiment of the present invention is applied to a vehicle-mounted antenna.

FIG. 4 is a diagram showing a detailed configuration when the multi-resonant antenna according to the first embodiment of the present invention is applied to a vehicle-mounted antenna.

FIG. 5 is a diagram illustrating a schematic configuration of a multi-resonant antenna according to a second embodiment of the present invention when the antenna is extended.

FIG. 6 is a diagram showing a schematic configuration when a multi-resonant antenna according to a second embodiment of the present invention is housed.

FIG. 7 is a diagram illustrating a schematic configuration when a multi-resonant antenna according to a third embodiment of the present invention is extended.

FIG. 8 is a diagram showing a schematic configuration when a multi-resonant antenna according to a third embodiment of the present invention is housed.

FIG. 9 is a diagram showing an external configuration when the multi-resonant antenna according to the second embodiment of the present invention is applied to an antenna for a portable device.

FIG. 10 is a half sectional view showing a detailed configuration when the multi-resonant antenna according to the second embodiment of the present invention is applied to an antenna for a portable device.

FIG. 11 is a diagram illustrating a state when a multi-resonant antenna according to a second embodiment of the present invention is extended and a state when the multi-resonant antenna is stored.

FIG. 12 is a diagram illustrating a schematic configuration of a multi-resonant antenna according to a fourth embodiment of the present invention, and a modification thereof.

13 is a diagram showing resonance characteristics of the multi-resonance antenna of the present invention shown in FIG.

14 is a diagram showing resonance characteristics of the multi-resonance antenna of the present invention shown in FIG.

FIG. 15 is a diagram showing resonance characteristics of the multi-resonance antenna of the present invention shown in FIG.

[Description of Signs] 1,3,7,8 Parasitic antenna element 2 Whip antenna element 4 Helical antenna element 5 Signal source 6 Matching circuit 10 Multi-resonant antenna 11 Mounting part 12 Cable 13 Antenna cover 20,40,41,42 Insulation Cylindrical body 31 Top 32 Top plug 33 Coated tube 34 Holder 35 Stopper 50 Housing 51 Screw part

Claims (6)

[Claims] A first antenna element having one end serving as a feeding point; and a second coil-shaped member fitted to the first antenna element so as to be electromagnetically coupled to the first antenna element.
A multi-resonant antenna characterized by having the antenna element of (1) and (2) to resonate in two separate frequency bands. 2. The method according to claim 1, wherein the first antenna element is formed of a linear wire, and the upper end of the first antenna element is mounted on the outer peripheral surface of an insulating cylinder having a lower end fitted therein. The multi-resonant antenna according to claim 1, wherein the second antenna element is formed in the formed groove. 3. A coil-shaped second antenna element fitted to the first antenna element so as to be electromagnetically coupled to a linear first antenna element having one end serving as a feeding point. A first antenna that resonates in two separated frequency bands, and a coil-shaped third antenna that is electrically insulated and disposed so as to be integrated with the extension direction of the first antenna and has one end serving as a feeding point. And a coil-shaped fourth antenna element fitted on the third antenna element so as to be electromagnetically coupled to the third antenna element. And a second antenna that resonates with the multi-resonant antenna, wherein when the multi-resonant antenna is extended from the mounting body, power is supplied only to the first antenna and the multi-resonant antenna is mounted. Housed in the body Multi-resonance antenna come in, characterized in that it is to be powered only in the second antenna. 4. The outer periphery of a first insulating cylinder in which the first antenna element is formed of a linear wire and the lower end of the first antenna element is inserted into the upper end of the first antenna element. The second antenna element is formed in a helical groove formed on the surface, and the third antenna element is formed in a helical groove formed on the outer peripheral surface of the second insulating cylinder. The fourth insulating cylinder is formed in the helical groove formed on the outer peripheral surface of the third insulating cylinder, the lower end of which is inserted into the upper end of the second insulating cylinder. An antenna element is formed, and a conductive stopper fixed to a lower end of the first antenna element is a feed point of the first antenna.
A conductive top plug whose lower end is fitted to the upper end of the first insulating tubular body and whose upper end is fitted to the lower end of the second insulating tubular body is connected to the second insulating tubular body. The multi-resonant antenna according to claim 3, wherein the multi-resonant antenna is a feed point of the antenna. 5. A coil-shaped second antenna element fitted to the first antenna element so as to be electromagnetically coupled to a linear first antenna element having one end serving as a feeding point. A first antenna that resonates in two separated frequency bands, a coil-shaped third antenna that is electrically insulated so that the first antenna can slide inside and has one end serving as a feeding point; And a coil-shaped fourth antenna element fitted on the third antenna element so as to be electromagnetically coupled to the third antenna element.
A multi-resonant antenna comprising the second antenna resonating in the two separated frequency bands, wherein when the multi-resonant antenna is extended from the mounting body, power is supplied to the first antenna; A multi-resonant antenna, wherein when the multi-resonant antenna is stored in a mounting body, power is supplied only to the second antenna. 6. A first antenna element having one end serving as a feeding point, and a coil-shaped second antenna fitted to the first antenna element so as to be electromagnetically coupled to the first antenna element.
And a coil-shaped third antenna element fitted to the second antenna element so as to resonate in multiple frequency bands separated from each other. Multi-resonant antenna.