WO2003107478A1 - Multi-resonance antenna and antenna for portable radio - Google Patents

Abstract

A small antenna operating at a plurality of frequency bands comprising a pattern of antennal elements (14) resonant at a plurality of frequency bands formed as a plurality of helical lines on the outer circumferential surface of an antenna bobbin (12). A parasitic conductor (11) is fitted in a containing hole made substantially along the central axis of the antenna bobbin (12). An antenna operating well at two frequency bands of 800 MHz and 1.4 GHz of PDC can thereby be obtained.

Description

 Description Multi-resonant antenna and antenna for portable radio

 The present invention relates to a multi-resonance antenna operating in a plurality of frequency bands and an antenna for a portable wireless device. Background art

 The frequency band used by a mobile telephone system is generally a plurality of frequency bands. Example: XJ, the PDC system (Personal Digital Cellular telecommunication system) in Japan uses the 800 MHz band (810 MHz to 956 MHz) and the 1.4 GHz band (1429 MHz to 501 MHz). In the digital senerora system in the United States, 900 MHz band (824 MHz to 894 MHz) power as AMPS (Advanced Mobile Phone Service) system and 1.8 GHz band (1850 MHz) as PCS (Presonal Communication Service) system ~ 1990 MHz) is at least used. In Europe, the 900 GHz band (870 MHz to 960 MHz) as the GSM (Global System for Mobile communications) system and the 1.8 GHz band (1 710 MHz to 880 MHz) as the DCS (Digital Cellular System) system are available. It is used. The reason for using multiple frequency bands in this way is that the number of subscribers increases and one frequency band lacks available frequencies.

As described above, a portable wireless device that receives or transmits a plurality of frequency bands needs to be equipped with an antenna that operates in a plurality of frequency bands. Therefore, conventionally, as an antenna operating in a plurality of frequency bands, a planar antenna or a small-volume chip antenna has been built in the radio housing in addition to the main external antenna. However, this has the problem that the antenna takes up the volume inside the wireless device housing, which is incompatible with miniaturization of the wireless device. Furthermore, when the portable wireless device is held by the user, the built-in antenna is more likely to be covered by the hand, and the antenna characteristics when using the portable wireless device are reduced. There was also a problem of deterioration.

 There is also a method of using a one-element helical antenna and forcibly causing multiple resonance by an impedance matching circuit to obtain a multiple resonance antenna. Fig. 13 shows an example of a helical antenna in this case. The helical antenna shown in Fig. 13 has a single helical element 114a formed on the outer peripheral surface of an insulative circular antenna bobbin 112, and a power supply ring 1 serving as a power supply at the lower end. 14b is formed. The frequency characteristics of the voltage standing wave ratio (VSWR) in the frequency band when the length of the element 114a is determined so that this helical antenna operates in the 800MHz band and the 1.4GHz band of the PDC system are described in the following. It is shown in Figure 14. Referring to Fig. 14, it can be seen that the VSWR of the PDC system in the 80 OMHz band is about 3.5 or less, but the VSWR in the 1.4 GHz band is about 9.5 or less, which is unpractical. .

 As described above, there has been a problem that it is difficult to obtain satisfactory antenna electrical characteristics in a plurality of frequency bands in a portable radio antenna using a combination of a one-element whip antenna or a helical antenna and a matching circuit. Furthermore, it is conceivable to use antenna elements that operate independently in each frequency band in a plurality of frequency bands as antennas. However, there has been a problem that it is difficult to apply the method to mobile phones and wire machines.

 Accordingly, it is an object of the present invention to provide a miniaturized double resonance antenna and a mobile / radio antenna that operate well in a plurality of frequency bands. Disclosure of the invention

 In order to solve the above-mentioned problems, a multiple resonance antenna according to the present invention includes an insulating antenna box formed on an outer peripheral surface of a pattern of elements that resonate in a plurality of frequency bands, and a central axis of the antenna pobin. And a conductive parasitic conductor fitted in a storage hole formed substantially along the line, and the pattern of the element is a plurality of helical patterns.

Further, in the multiple resonance antenna according to the present invention, the lower portion of the antenna pobin is connected The antenna holder and the element are electrically connected to each other by being fitted to an electrically conductive antenna holder, and an insulating cap covering the antenna pobin is fitted to the antenna holder. Is also good.

 Further, in the multiple resonance antenna of the present invention, a conductive film may be formed on the inner peripheral surface of the storage hole in the antenna pobin instead of the parasitic conductor.

 Next, an antenna for a portable wireless device according to the present invention, which can solve the above-mentioned problem, comprises: a whip portion that is extendable and retractable with respect to a holder portion that can be fixed to a housing of the portable wireless device; And a top portion fixed to the end of the portable radio device via an insulating portion, wherein the top portion has a plurality of helical element patterns that resonate in a plurality of frequency bands. An insulated antenna pobin, a conductive parasitic conductor inserted in a storage hole formed substantially along the central axis of the antenna pobin, and a lower part of the antenna pobin. A diameter-enlarged portion fitted and electrically connected to the element; a conductive plug portion having a small-diameter portion inserted into the holder portion when retracted; and covering the antenna bobbin. Absolute The whip portion is slidable in the holder portion; a conductive stopper portion provided at a lower end and held in the holder portion when extended; A whip portion and an insulating insulating portion provided so as to connect the top portion, wherein an upper portion is fixed to the plug portion, and a lower portion is fixed to a tip of the whip portion. The top portion and the whip portion are substantially uniaxially arranged and fixed by the insulating portion. Further, in the portable wireless device antenna of the present invention, in place of the parasitic conductor, A conductive film may be formed on the inner peripheral surface of the storage hole in the antenna pobin.

According to the present invention as described above, a conductive parasitic conductor is inserted into a storage hole of an insulating antenna bobbin in which a pattern of a plurality of helical elements resonating in a plurality of frequency bands is formed. Because of this, it is possible to increase the bandwidth and operate in a plurality of frequency bands. can do. Moreover, the size can be reduced.

 In addition, when a telescopic mobile radio antenna including such a multi-resonant antenna as a top portion of the antenna is configured, a mobile phone having good electrical characteristics in a wide band capable of operating in a plurality of frequency bands is provided. It can be a radio antenna. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a diagram showing a configuration of a portable wireless device including a multiple resonance antenna according to an embodiment of the present invention.

 FIG. 2 is an exploded view showing a configuration of a fixed antenna unit according to the embodiment of the multiple resonance antenna of the present invention.

 FIG. 3 is a perspective view showing a configuration of a fixed antenna unit according to the embodiment of the multiple resonance antenna of the present invention.

 FIG. 4 is a cross-sectional view showing a configuration of a fixed antenna unit according to an embodiment of the multiple resonance antenna of the present invention.

 FIG. 5 is a cross-sectional view showing a configuration of a fixed antenna unit according to an embodiment of the multiple resonance antenna of the present invention.

 FIG. 6 is a diagram showing a detailed configuration of an antenna pobin in the fixed antenna unit according to the embodiment of the multiple resonance antenna of the present invention.

 FIG. 7 is a diagram showing a frequency characteristic of V SWR in a fixed antenna unit having no parasitic element according to the embodiment of the present invention.

 FIG. 8 is a diagram showing a frequency characteristic of V SWR in a fixed antenna unit having a parasitic element according to the embodiment of the present invention.

 FIG. 9 is a diagram showing a configuration of a portable wireless device including the portable wireless device antenna according to the embodiment of the present invention.

 FIG. 10 is a diagram showing a relationship between the antenna for a portable wireless device according to the embodiment of the present invention and a circuit board built in the portable wireless device.

FIG. 11 is a perspective view showing an overall configuration of an antenna for a portable wireless device according to an embodiment of the present invention. FIG. 12 is a cross-sectional view showing a configuration of the antenna for a portable wireless device according to the embodiment of the present invention when the top portion is extended.

 FIG. 13 is a diagram showing a configuration of a conventional helical antenna.

 FIG. 14 is a diagram showing the frequency characteristic of V S WR of a conventional helical antenna.

BEST MODE FOR CARRYING OUT THE INVENTION

 FIG. 1 shows a configuration of a portable wireless device including a multiple resonance antenna according to an embodiment of the present invention.

 The portable wireless device 1 shown in FIG. 1 is a mobile phone, for example, and includes a wireless device housing 1a in which a telephone function circuit unit and a battery are stored. Various buttons including a dial button and a display are provided. Further, a fixed antenna unit 2 which is a multiple resonance antenna according to the present invention is fixed to the upper surface of the wireless device casing 1a. The fixed antenna section 2 is an antenna operable in two frequency bands, for example, the 80 MHz band and the 1.4 GHz band of the PDC system.

 Next, FIG. 2 shows an exploded view of the fixed antenna unit 2, and FIGS. 3 to 5 show the configuration of the fixed antenna unit 2. FIG. However, FIG. 3 is a perspective view showing the configuration of the fixed antenna unit 2, FIG. 4 is a cross-sectional view of the fixed antenna unit 2, and FIG. 5 is a cutaway of the antenna bobbin 12 of the fixed antenna unit 2. It is sectional drawing shown without doing.

In these figures, for example, a conductive antenna holder 13 made of metal has a screw portion 13b formed on an outer peripheral surface thereof, and a concave fitting portion 13a formed on an upper surface thereof. I have. The lower part of the antenna pobin 12 is fitted into the fitting portion 13a. The antenna bobbin 12 is made of an insulating material such as a synthetic resin and has a substantially circular cross section. On the outer peripheral surface of the antenna pobin 12, a pattern of a plurality of helical antenna elements 14 resonating in a plurality of frequency bands is formed. This pattern is formed as a conductive film on the outer peripheral surface of the antenna pobin 12 by conductive foil printing, conductive powder deposition, plating, or the like, and has a ring-shaped pattern under the antenna bobbin 12. . This ring-shaped pattern is When the antenna 12 is inserted into the insertion portion 13 a of the antenna holder 13, the power supply portion is electrically connected to the antenna holder 13.

 The antenna pobin 12 fixed to the antenna holder 13 is provided with a storage hole 12a along the center axis so as to substantially correspond to the portion where the antenna element 14 is formed. A conductive parasitic conductor 11 made of, for example, metal and formed into a cylindrical shape is inserted into the storage hole 12a. In this state, an insulating cap portion 10 made of, for example, a synthetic resin is placed from above so as to store the antenna pobin 12 in the storage portion 10a of the cap portion 10. Then, the fitting portion 10b provided at the lower portion of the cap portion 10 is fitted and fixed to the upper portion of the antenna holder 13. The antenna holder 13 of the fixed antenna unit 2 configured as described above is inserted into the through hole provided on the upper surface of the wireless device housing 1a, and the inside of the waterless device housing 1a is inserted. By screwing the holder nut to the screw portion 13b of the antenna holder 13 from above, the fixed antenna portion 2 is fixed to the wireless device housing 1a. At this time, the terminal comes into contact with the antenna holder 13, and the radio circuit incorporated in the radio case 1 a and the fixed antenna section 2 are electrically connected.

 Here, the detailed configuration of the antenna bobbin 12 is shown in FIG.

 The antenna pobin 12 is composed of an insulator with a substantially circular cross section, and its outer peripheral surface has a first element 14a, a second element 14b, and a third element 14 as shown in FIG. An antenna element 14 consisting of three helical patterns of c is formed. The helical first element 14a to third element 14c have almost the same length, but their lengths are adjusted so that good electrical characteristics can be obtained in the operating frequency band. ing. Further, the lower ends of the first element 14a to the third element 14c are connected to a power supply ring part 14d formed below the antenna pobin 12, and the power supply ring part is formed. The power supply section 14 d is inserted into the insertion section 13 a of the antenna holder 13 to be in contact therewith.

The fixed antenna section 2 in which the antenna element 14 having the pattern shown in FIG. 6 is formed on the outer peripheral surface of the antenna bobbin 12 is used in the 800 MHz band of the PDC system. And 1.4 GHz band, the first element 14a to the third element 14c are located close to each other, so that the first element 14a to the third The elements 14c are not operated independently, but are influenced by each other. As a result, the antenna element 14 as a whole can operate in two frequency bands of the PDC system. Furthermore, the parasitic conductor 11 fitted in the storage hole 12a of the antenna bobbin 12 is disposed close to the pattern of the antenna element 14, and as a result of the influence of the parasitic conductor 11, The band is widened and the electrical characteristics are improved in the two frequency bands of the PDC system. Thus, the fixed antenna unit 2 can operate in two frequency bands of the PDC system. Since the impedance of the fixed antenna section 2 is a three-strip pattern and is approximately 5 Ω in an operable frequency band, a matching circuit for matching with a radio circuit can be omitted.

 Here, the frequency characteristics of the voltage standing wave ratio (VSWR) of the fixed antenna unit 2 having the antenna element 14 shown in FIG. 6 are shown in FIG. 7 in a case where the parasitic conductor 11 is not provided. Figure 8 shows the case where

 As shown in Fig. 7, the frequency characteristics of the VSWR in the fixed antenna section 2 without the parasitic conductor 11 are about 3.0 or less in the 80-MHz band (81 MHz to 956 MHz) of the PDC system. However, in the 1.4 GHz band (14 29 MHz to 1501 MHz), it has deteriorated to about 4.0 or less. On the other hand, the frequency characteristics of the VSWR in the fixed antenna section 2 provided with the parasitic antenna 11 are as shown in Fig. 8 in the 8 OOMHz band (810MHz to 960MHz) of the PDC system. It has been improved to about 2.5 or less, and also improved to about 3.0 or less in the 1.4 GHz band (1429 MHz to 1501 MHz).

 In this way, the provision of the parasitic antenna 11 improves the bandwidth and improves the electrical characteristics in the two frequency bands of the 800 MHz band and the 1.4 GHz band of the PDC system. It can be seen that the fixed antenna section 2 can operate in the frequency band.

Next, a portable radio equipped with a portable radio antenna according to an embodiment of the present invention Fig. 9 shows the configuration of the portable radio, and Fig. 10 shows the relationship between the circuit board built in the portable radio and the antenna for the portable radio.

 The mobile wireless device 1 shown in FIG. 9 is, for example, a mobile phone, and has a wireless device housing 1a containing a telephone function circuit unit and a battery. Various buttons including dial buttons and a display are provided. The antenna 3 for a portable wireless device according to the present invention is fixed to the upper surface of the wireless device housing 1a. The portable wireless device antenna 3 is an antenna operable in two frequency bands of, for example, the 80-MHz band and the 1.4-GHz band of the PDC system. The portable wireless device antenna 3 includes a whip portion 5 and a top portion 8 fixed to an upper end of the whip portion 5 via an insulating portion 6. The whip unit 5 is made to be able to expand and contract with respect to the holder unit 4 that is fixed to the radio housing 1a, and the whip unit 5 is fixed to the radio housing 1a so that the whip unit 5 is fixed. It is extendable with respect to the housing 1a. In this case, the holder unit 4 is passed through the through hole provided on the upper surface of the wireless device housing la, and the holder nut is inserted from inside the wireless device housing 1a as shown in FIG. By screwing 1b to the lower part of the holder unit 4, the holder unit 4 is fixed to the wireless device casing 1a. At this time, the contact terminal 1c, one end of which is soldered to the circuit board 1d, comes into contact with the holder section 4, and the RF circuit 1e provided on the circuit board 1d and the holder section 4 Will be electrically connected. Since the impedance of the portable wireless device antenna 3 is approximately 50 Ω in an operable frequency band, a matching circuit for matching the portable wireless device antenna 3 and the RF circuit 1 e is omitted. Can be.

 Next, FIG. 11 shows the entire configuration of the antenna 3 for a portable wireless device according to the present invention, and FIG. 10 is a cross-sectional view showing a state where the whip portion 5 is extended.

 As shown in these figures, the top part 8 is fixed to the tip of the whip part 5 by an insulating part 6. The top part 8 includes a metal plug part 7, an insulated antenna bobbin 12 whose lower part is fitted or screwed to the plug part 7, and a housing formed substantially at the center of the antenna bobbin 12. An antenna is placed in the hole 12a so as to cover the conductive parasitic conductor 11 made of metal, for example, and the antenna pobin 12.

Insulation that is covered by 2 and the lower part is fitted or screwed into the plug part 7 And a cap portion 10. The configuration of the top section 8 is almost the same as that of the fixed antenna section 2 described above. Good electrical characteristics are improved in the two frequency bands of the 1.4 GHz band. This allows operation in two frequency bands of the PDC system.

 The upper part of the plug part 7 is a large diameter part with a large diameter, and a small diameter part with a small diameter is extended downward from the large diameter part. An antenna bobbin 12 is fitted or screwed into the enlarged diameter portion, and an insulating portion 6 is fitted into the through hole of the small diameter portion and fixed to the plug portion 7. Is integrally formed with the tip of the element 5a in the whip portion 5. Thus, the whip portion 5 and the top portion 8 are arranged substantially uniaxially and mechanically fixed. When the whip portion 5 is retracted with respect to the holder portion 4, the plug portion 7 is fitted into the holder portion 4 and is held by the metal holding panel 4 c such as phosphor bronze in the holder portion 4. Is done. As a result, an antenna element 14 formed on the antenna bobbin 12 as shown in FIG. 6 is electrically connected to the holder 4. In this case, since the whip portion 5 is electrically insulated by the insulating portion 6, only the top portion 8 operates as an antenna. The frequency characteristic of the VS WR when the top part 8 is operated by contracting the antenna 3 for the portable radio becomes almost the same as the frequency characteristic of the VS WR shown in FIG. Operable in two frequency bands.

The whip portion 5 includes a linear element 5a made of, for example, a superelastic metal, and an insulating tube 5b covered by the element 5a. At the lower part of the element 5a, a metal stopper part 9 is swaged, and when it extends with respect to the holder part 4 as shown in FIG. 12, the stopper part 9 is lowered inside the holder part 4. Will be inserted from. At this time, the stopper portion 9 is held by the holding panel 4c in the holder part 4, so that it does not come off and is electrically connected. As a result, the whip section 5 is activated, but the top section 8 is insulated by the insulating section 6 and does not operate. At the lower end of the stopper portion 9, a flange-shaped engaging portion 9a is formed, and when the whip portion 5 is extended, the engaging portion 9a abuts against the lower end of the holder portion 4, and further. It cannot be extended. As a result, the whip portion 5 does not come out of the holder portion 4. At the top of the holder part 4, when the holder part 4 is passed through the mounting hole formed in the radio equipment casing 1a, there is no taku part 4a that comes into contact with the equipment casing 1a. On the outer peripheral surface of the holder part 4, a screw part 4b to which the holder nut 1b is screwed is formed. In the fixed antenna part 2 described above, instead of fitting the parasitic conductor 11 into the storage hole 12 a formed in the antenna pobin 12, the inner peripheral surface of the storage hole 12 a The conductive film may be formed by conductive foil printing, conductive powder deposition, plating, or the like.

 Further, in the above description, the fixed antenna unit 2 and the portable radio antenna 3 according to the present invention are operable in two frequency bands in the PDC system. However, the present invention is not limited to this. It may be possible to operate in the two frequency bands of GSM and DCS. In addition, the antenna may be operable as a GPS antenna. Industrial applicability

 As described above, a conductive parasitic conductor is fitted into a storage hole of an insulating antenna pobin in which a plurality of helical element patterns resonating in a plurality of frequency bands are formed. As a result, a multi-resonant antenna having good electrical characteristics that can be made broadband and can be operated in a plurality of frequency bands can be obtained. Moreover, the size can be reduced.

 In addition, when a telescopic portable wireless antenna having such a multi-resonant antenna as a top portion of the antenna is constructed, the electrical characteristics can be reduced in a wide band which can operate in a plurality of frequency bands, and the electric characteristics can be reduced. Mobile radio antenna.

Claims

The scope of the claims  1. The pattern of the element that resonates in a plurality of frequency bands is composed of an insulating antenna bobbin formed on the outer peripheral surface,  A conductive parasitic conductor fitted in a storage hole formed substantially along the center axis of the antenna bobbin,  Wherein the pattern of the element is a plurality of helical patterns. 2. The lower part of the antenna bobbin is fitted into a conductive antenna holder, the antenna holder and the element are electrically connected, and the insulating cap covering the antenna bobbin is connected to the antenna holder. 2. The multiple resonance device according to claim 1, wherein 3. The multiple resonance antenna according to claim 1, wherein a conductive film is formed on an inner peripheral surface of the storage hole in the antenna bobbin, instead of the parasitic conductor. 4. A wobble part that can be extended and retracted with respect to a holder part that can be fixed to the housing of the portable wireless device, and a top part that is fixed to the tip of the whip part via an insulating part. Mobile radio / wireless machine antenna,  The top portion includes an insulating antenna bobbin having a plurality of helical element patterns resonating in a plurality of frequency bands formed on an outer peripheral surface thereof, and a storage hole formed substantially along a central axis of the antenna bobbin. A conductive non-powered conductor inserted in the antenna, a large-diameter portion in which the lower part of the antenna nabbin is fitted and the element is electrically connected, and a holder inside the holder when retracted. A conductive plug portion having a small-diameter portion through which it passes, and an insulating cap portion covering the antenna pobin, The whip portion is slidable in the holder portion, and is provided at a lower end and extends. A part of a conductive stopper held in the holder portion when the operation is performed, and an insulating insulating portion provided to connect the whip portion and the top portion,  The top portion and the whip portion are substantially uniaxially arranged and fixed by the insulating portion having an upper portion fixed to the plug portion and a lower portion fixed to the tip of the whip portion. An antenna for a portable wireless device. 5. The antenna for a portable wireless device according to claim 4, wherein a conductive film is formed on an inner peripheral surface of said storage hole in said antenna bobbin, instead of said parasitic conductor.