JP2006254081A - Dipole-type antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dipole-type antenna having a simple structure applicable to a mobile terminal, and capable of obtaining wide-band characteristics. <P>SOLUTION: The antenna comprises two conductor plates 1 and 2 of a rectangle shape having different length and width, respectively. Each of one side of the two conductor plates 1 and 2, in the longitudinal direction is placed in a straight line and each of one side in the width direction is placed in close at a predetermined gap on a flat surface or a substantially flat surface. A feeding line 3 is connected to each of the two conductor plates 1 and 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a dipole antenna applied to a portable terminal for wireless communication, for example, mobile wireless communication.

  Mobile radio communication portable terminals are being shared for adapting to a plurality of radio communication systems. Since the radio communication system is assigned a frequency band of radio waves to be used, sharing various radio communication systems corresponds to different frequency bands, that is, broadband radio waves. Therefore, it is required to increase the bandwidth of the antenna of the mobile terminal.

Resonates in a plurality of frequency bands, as an antenna for a conventional portable terminal that allows the sharing of the plurality of wireless communication systems, and linear feeder element having a length L _1, one end is short-circuited to the power supply element, and a linear folded element having closely spaced length L _2, the length L ₂ of the folded element, are set so as to resonate in a higher frequency in L ₁ -L _2, the feed element There is a technique in which the length L ₁ is set to a length that acts with the folding element and resonates at the lower frequency at the lower frequency (see, for example, Patent Document 1). Patent Document 1 further describes that this antenna is formed as a planar antenna by forming a feeding element and a folding element with a strip line.

Japanese Patent Laid-Open No. 10-51224 (FIG. 1)

  The conventional antenna is configured to obtain a double resonance by folding the linear antenna element as described above, but can obtain only two resonances. The frequency bands of a plurality of communication methods are not necessarily two frequency bands and may be three or more frequency bands, and each frequency band may not be close to each other and may be separated and scattered. Conventional antennas of portable terminals cannot sufficiently cope with the broadband including these. In particular, in recent years, functions of new frequencies such as short-range wireless Bluetooth (registered trademark) 2.4 GHz, wireless LAN 2.4 GHz, and 5.0 GHz have been demanded. There is a problem that it is not possible to cope with a wide band including these. In addition, as an antenna of a mobile terminal, there are a dipole antenna that is symmetrically arranged using two rectangular conductor plates of the same size, or a unipole antenna in which a linear radiation conductor and a rectangular conductor plate are adjacently arranged. Even if two resonance points were obtained, matching at the frequency of each point could not be obtained, which was not suitable for widening the band.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a dipole antenna having a simple structure that can obtain broadband characteristics and can be applied to a mobile terminal.

  The dipole antenna according to the present invention has two conductor plates made of rectangles having different lengths and widths, and straight lines are provided on one side in the length direction of the two conductor plates on a plane or a substantially plane. It is configured so as to form an arrangement in which one side in the width direction is adjacent to each other at a predetermined interval, and a feeder line is connected to each of the two conductor plates.

  According to the present invention, since an asymmetric dipole antenna is formed, two or more series resonances can be generated by a combination of the length and width of the conductor plate to be used. . In addition, since a conductor plate is used as the antenna element, a simple and stable structure can be obtained using a printed board so as to be suitable for a portable terminal.

Embodiment 1 FIG.
1 is a perspective view showing a configuration of a dipole antenna according to Embodiment 1 of the present invention.
In the figure, this dipole antenna has a first conductor plate 1 and a second conductor plate 2 each having a rectangular shape with a different length and width. The two conductor plates 1 and 2 are arranged on the same plane so that the sides 101 and 201 in the length direction of the two conductor plates 1 and 2 are aligned on a straight line, and the sides 102 and 202 in the width direction have a predetermined interval. It arrange | positions so that it may adjoin apart. That is, the arrangement of the first conductor plate 1 and the second conductor plate 2 is asymmetric. In addition, a power supply line 3 is connected to a portion where the gap between the first conductor plate 1 and the second conductor plate 2 is opposed to form a power supply unit. Here, the length of the first conductor plate 1 is L1 and the width W1, and the length of the second conductor plate 2 is L2 and the width W2. This dipole antenna can have a stable structure by using a printed circuit board and forming the first conductor plate 1 and the second conductor plate 2 with the conductive foil.

When the voltage of the transmission signal is applied to the feeder 3, current flows through the first conductor plate 1 and the second conductor plate 2, and radio waves are radiated. Since the arrangement configuration of the first conductor plate 1 and the second conductor plate 2 is asymmetric, a plurality of series resonances are generated as follows. That is, resonance occurs in which the sum of the length L1 of the first conductor plate 1 and the length L2 of the second conductor plate 2 is an integral multiple of ½ wavelength. Further, resonance occurs in which the sum of the width W1 of the upper side of the first conductor plate 1 and the length L2 of the second conductor plate 2 is an integral multiple of ½ wavelength. Furthermore, resonance occurs in which the sum of the length L1 of the first conductor plate 1 and the length L2 of the second conductor plate 2 is an integral multiple of one wavelength. Note that a conventional dipole antenna in which conductor plates of the same size are arranged symmetrically cannot obtain resonance at a frequency between ½ wavelength and 1 wavelength.
Further, since the antenna element is a conductor plate, currents in various directions flow through the plate-shaped surface, and current paths with various lengths are generated. Since current paths having various lengths are generated, various resonances occur at different frequencies, and changes due to frequencies can be reduced. As a result, it is possible to obtain broadband characteristics even when the resonance frequencies are separated.

FIG. 2 shows an equivalent circuit of the dipole antenna of FIG. In the figure, Z ₁ , Z ₂ and Z ₃ represent impedances at three resonance frequencies. Z _in represents the overall impedance. In this equivalent circuit, the following equations hold.

  In the dipole antenna according to the first embodiment, as described with reference to FIG. 1, the first and second conductive plates are asymmetrical. As a result, the configuration shown in FIG. There is a great effect. FIG. 3 shows the voltage standing wave ratio (hereinafter referred to as VSWR) with respect to the frequency obtained by numerical analysis using the impedance equation obtained from the equivalent circuit and further providing a quarter wavelength matching circuit. The vertical axis represents the value of VSWR, and the horizontal axis represents the frequency. The thick line represents the value of the dipole antenna of the first embodiment, and the thin line represents the value of a conventional dipole antenna constructed symmetrically using two rectangular conductor plates of the same size. Assuming that the antenna operates within the range of VSWR of 1.0 to 2.0, it can be seen that the dipole antenna according to the first embodiment has a wider band characteristic than the conventional dipole antenna.

  FIG. 4 shows the VSWR obtained by conducting the numerical analysis by dividing the analysis region into a finite number and analyzing it using the finite element method and providing a quarter-wavelength matching circuit for the result. The dimensions [unit: mm] of the dipole antenna of the present invention used in this analysis are L1 = 110, L2 = 60, W1 = 40, and W2 = 20. It can be seen from FIG. 4 that a band with VSWR of 2 or less is obtained from 0.61 GHz to 2.55 GHz. With a conventional dipole antenna, only a bandwidth of 20% can be obtained, but compared with that, a broadband characteristic can be obtained.

  As described above, according to the first embodiment, the two conductive plates 1 and 2 made of rectangles having different lengths and widths are used, and the sides 101 and 201 in the respective length directions are formed on the plane. Since the arrangement is made such that the sides 102 and 202 in the width direction are aligned on a straight line and close to each other at a predetermined interval, the power supply line 3 is connected to each of the two conductor plates 1 and 2. It is possible to form a dipole antenna having asymmetric arrangement. Therefore, it is possible to generate two or more series resonances by the combination of the length and width of the conductor plates 1 and 2, and to obtain a broadband characteristic from 0.61 GHz to 2.55 GHz even when the VSWR is 2 or less. The effect that it can be obtained.

Embodiment 2. FIG.
FIG. 5 is a perspective view showing the configuration of a dipole antenna according to Embodiment 2 of the present invention. In the figure, portions corresponding to those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted in principle.
This dipole antenna uses a printed circuit board 4, and a first conductive plate 1 made of conductive foil is provided on the back surface of the printed circuit board 4 by the conductive foil, and the second conductive plate 2 made of conductive foil and a transmitter / receiver circuit are provided on the front surface. Part 5 is provided. A feeder line 3 is connected to the first conductor plate 1 and the second conductor plate 2 from the transceiver circuit unit 5. In this case, the power supply line 3 to the first conductor plate 1 on the back surface may be connected via a through hole. In this configuration, since the printed circuit board 4 is thick, the first conductor plate 1 and the second conductor plate 2 are not strictly on the same plane, but are the same as the dipole antenna of the first embodiment. Since the same effect can be obtained by the operation, both the conductor plates are treated as being provided on substantially the same plane in the configuration of the invention. Further, the first conductor plate 1 and the second conductor plate 2 may be formed on the same surface of the printed circuit board 4.

  As described above, according to the second embodiment, the first conductor plate 1 and the second conductor plate 2 made of conductive foil are formed on the printed circuit board 4, and these conductor plates 1, 2 are formed on the same printed circuit board. And the transmitter / receiver circuit unit 5 are integrated to form a dipole antenna, so that in addition to the effects of the first embodiment, a structure suitable for miniaturization of a portable terminal can be achieved, and the shape of the antenna element The unit structure can be made stable.

Embodiment 3 FIG.
FIG. 6 is a perspective view showing the configuration of a dipole antenna according to Embodiment 3 of the present invention. Parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted in principle.
This dipole antenna has two plates or boxes 41 and 42 that can be folded by the hinge portion 6, the first conductor plate 1 is provided on the front or back surface of one of the plates 41, and the second conductor 42 is provided on the front or back surface of the other 42. 2 conductor plates 2 are provided. When a box is used, the transmitter / receiver circuit unit 5 is provided inside one of them. By folding the plates or boxes 41 and 42, the two conductor plates 1 and 2 can be folded. When the two plates or boxes 41, 42 are opened, that is, in the state of FIG. 6, the sides 101, 201 in the length direction of the two conductor plates 1, 2 are aligned on a plane, and The dipole antenna is the same as that of the first embodiment in which the respective sides 102 and 202 in the width direction are arranged close to each other at a predetermined interval.
In an actual folding mobile phone, the two boxes are configured to be given a slight inclination when opened. In this case, the operation is the same as that of the dipole antenna of the first embodiment. Therefore, in the present invention, the same surface is used.

  As described above, according to the third embodiment, since the first conductor plate 1 and the second conductor plate are folded by the hinge portion 6, in addition to the effects of the first embodiment, the folding portable The effect that can be applied to the telephone is obtained.

Embodiment 4 FIG.
FIG. 7 is a perspective view showing a configuration of a dipole antenna according to Embodiment 4 of the present invention. In the figure, portions corresponding to those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted in principle.
This dipole antenna has a configuration in which an appropriate number of slits 7 are provided on the side 102 of the first conductor plate 1 adjacent to the second conductor plate 2. By providing the slit 7, the width of the first conductor plate 1 is reduced by an amount corresponding to the width of the slit from the apparent width W <b> 1 (this is referred to as an equivalent width). Therefore, the resonance frequency using the width of the first conductor plate 1 has a resonance frequency depending on this equivalent width.

  As described above, according to the fourth embodiment, one or more slits 7 for adjusting the equivalent width are provided on the side 102 of the first conductor plate 1 adjacent to the second conductor plate 2. The resonance frequency using the width of the first conductor plate 1 can be selected to an arbitrary value.

Embodiment 5. FIG.
FIG. 8 is a perspective view showing the configuration of a dipole antenna according to Embodiment 5 of the present invention.
This dipole antenna has a rectangular conductor plate 11 serving as a radiation conductor and a U-shaped conductor 12 formed in a U-shape by cutting out another rectangular conductor plate. The rectangular conductor plate 11 and the U-shaped conductor 12 are arranged on the same plane so that one side 101 of the rectangular conductor plate 11 in the longitudinal direction and one branch side 121 of the U-shaped conductor are aligned on a straight line. The one side 103 in the width direction of the conductor plate and the middle side 122 of the U-shaped conductor 12 are arranged close to each other at a predetermined interval. In this case, the direction of the branch 121 of the U-shaped conductor 12 is the length direction. In addition, a feeder line 3 is connected to a portion where the conductor plate 11 and the U-shaped conductor 12 face each other to form a feeder portion. Here, the length of the conductor plate 11 is L11 and the width W11, the length of the U-shaped conductor 12 is L12 and the width W12, L11 and L12 are different, and W11 and W12 are also different.

A voltage of a transmission signal is applied to the feeder 3, current flows through the conductor plate 11 and the U-shaped conductor 22, which are radiation conductors, and radio waves are emitted. The two conductors 11 and 12 cause a plurality of series resonances. Resonance occurs where the sum of the length L11 of the conductor plate 11 and the length L12 of the U-shaped conductor 12 is an integral multiple of ½ wavelength. Further, resonance occurs in which the sum of the length L11 of the conductor plate 11 and the width W12 of the intermediate side 122 of the U-shaped conductor 12 is an integral multiple of ½ wavelength.
The equivalent circuit of this dipole antenna is the same as that shown in FIG.

  Since the rectangular first conductor plate 1 of the first embodiment has a portion where no current flows, this dipole antenna is cut out to form a U-shaped conductor 12. With this configuration, the effect shown in FIG. 9 can be obtained. FIG. 9 shows the VSWR with respect to the frequency obtained by numerical analysis using the equation of impedance obtained from the equivalent circuit. The vertical axis represents the value of VSWR, and the horizontal axis represents the frequency. The thick line represents the value obtained with the equivalent circuit of FIG. 2 for the dipole antenna of the fifth embodiment, and the thin line represents the value of a conventional unipole antenna in which a linear radiating conductor and a rectangular conductor plate are arranged adjacent to each other. If the VSWR is in the range of 1.0 to 2.0, the unipole antenna operates, the dipole antenna according to the fifth embodiment has a wider band characteristic than the conventional unipole antenna. I understand.

  In addition, in the dipole antenna according to the fifth embodiment, the result of VSWR obtained by numerically analyzing the dimensions (unit: mm) of each part as L1 = 60, L2 = 110, W1 = 20, and W2 = 40 Represents the same characteristics as the graph of FIG. Also in this example, it was possible to obtain a band with VSWR of 2 or less from 0.61 GHz to 2.55 GHz. Compared with the 20% bandwidth of a conventionally used unipole antenna, a wide band characteristic can be obtained.

  As described above, according to the fifth embodiment, the one side 101 in the length direction of the rectangular conductor plate 11 serving as the radiation conductor and the one side 121 of the U-shaped conductor 12 are linearly arranged on a plane. And one side 103 in the width direction of the rectangular conductor plate 11 and the middle side 122 of the U-shaped conductor are arranged close to each other at a predetermined interval. Therefore, by using a U-shaped conductor, a broadband characteristic from 0.61 GHz to 2.55 GHz can be obtained even in a range where VSWR is 2 or less. The configuration of the fifth embodiment may be applied to the configuration of the third embodiment.

Embodiment 6 FIG.
FIG. 10 is a perspective view showing a configuration of a dipole antenna according to Embodiment 6 of the present invention. In the figure, parts corresponding to those in FIG. 8 are denoted by the same reference numerals, and detailed description thereof will be omitted in principle.
In this dipole antenna, the transmitter / receiver circuit unit 5 is arranged in the inner portion 124 after the U-shaped conductor 12 is cut out, and the rectangular conductor plate 11 and the U-shaped conductor 12 are fed from the transmitter / receiver circuit unit 5. The configuration is as follows. Thus, even if the transceiver circuit unit 5 is arranged in the space of the inner portion 124, the same effect as in the fifth embodiment can be obtained without any trouble. Moreover, it can comprise compactly on the assembly of an apparatus.

Embodiment 7 FIG.
FIG. 11 is a perspective view showing the configuration of a dipole antenna according to Embodiment 7 of the present invention. In the figure, parts corresponding to those in FIG. 8 are denoted by the same reference numerals, and detailed description thereof will be omitted in principle.
In this dipole antenna, a printed circuit board 41 is used, a rectangular conductor plate 11 and a U-shaped conductor 12 are provided on the surface of the printed circuit board 41, and a transmitter / receiver circuit is provided at a position on the back surface of the printed circuit board 41 corresponding to the inner portion 124. Part 5 is provided. Note that one of the rectangular conductor plate 11 and the U-shaped conductor 12 may be provided on the back surface of the printed circuit board 41.

  As described above, according to the seventh embodiment, the conductive plate 11 serving as the radiation conductor and the U-shaped conductor 12 are arranged on the printed circuit board 41 to constitute the dipole antenna. In addition to the effect, since the antenna and the transceiver circuit unit 5 are integrated on the same printed circuit board, a unit structure that is suitable for downsizing of the mobile terminal and that stabilizes the shape of the antenna element can be obtained.

Embodiment 8 FIG.
12 is a perspective view showing the structure of a dipole antenna according to an eighth embodiment of the present invention. In the figure, parts corresponding to those in FIG. 8 are denoted by the same reference numerals, and detailed description thereof will be omitted in principle.
This dipole antenna has a configuration in which a rectangular conductor plate 11 serving as a radiation conductor shown in FIG. 8 is cut out to form a U-shaped conductor 111 having the same shape as the U-shaped conductor 12. In this case, the intermediate side 122 of the U-shaped conductor 12 and the intermediate side 112 of the U-shaped conductor 111 are opposed to each other.
In this way, by using the U-shaped conductor 111 as the radiating conductor, it is possible to resonate twice by providing two current paths having different lengths, and the width of the resonating frequency is widened so that resonance can be easily obtained. it can. The configuration of the eighth embodiment may be applied to the configurations of the third embodiment, the sixth embodiment, and the seventh embodiment.

It is a perspective view which shows the structure of the dipole type antenna by Embodiment 1 of this invention. It is a circuit diagram which shows the equivalent circuit of the dipole type antenna which concerns on Embodiment 1 of this invention. It is explanatory drawing showing the voltage standing wave ratio of the dipole type antenna which concerns on Embodiment 1 of this invention. It is explanatory drawing showing the voltage standing wave ratio analyzed by the finite element method of the dipole type antenna which concerns on Embodiment 1 of this invention. It is a perspective view which shows the structure of the dipole type | mold antenna by Embodiment 2 of this invention. It is a perspective view which shows the structure of the dipole type | mold antenna by Embodiment 3 of this invention. It is a perspective view which shows the structure of the dipole type | mold antenna by Embodiment 4 of this invention. It is a perspective view which shows the structure of the dipole type | mold antenna by Embodiment 5 of this invention. It is explanatory drawing showing the voltage standing wave ratio of the dipole type antenna which concerns on Embodiment 5 of this invention. It is a perspective view which shows the structure of the dipole type | mold antenna by Embodiment 6 of this invention. It is a perspective view which shows the structure of the dipole type | mold antenna by Embodiment 7 of this invention. It is a perspective view which shows the structure of the dipole type | mold antenna by Embodiment 8 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 1st conductor board, 2nd conductor board, 3 feeder, 4,41 printed circuit board, 5 transceiver circuit part, 6 hinge part, 7 slit, 11 conductor board, 12,111 U-shaped conductor.

Claims (12)

  It has two conductor plates made of rectangles having different lengths and widths, and one side in the length direction of each of the two conductor plates is aligned on a plane or a substantially plane, and each width 2. A dipole antenna comprising a configuration in which one side in a direction is arranged close to each other at a predetermined interval, and a feed line is connected to each of the two conductor plates.   2. The dipole antenna according to claim 1, wherein the two conductive plates are formed of a conductive foil of a printed board.   3. The circuit board according to claim 2, wherein one of the conductor plates is formed, but a transceiver circuit unit is provided on the back surface of the printed circuit board, and power is supplied to the two conductor plates from the transceiver circuit unit. Dipole antenna.   One of the two conductive plates is provided on one of the two plates or box that is folded by the hinge portion, and the other of the two conductive plates is provided on the other of the two plates or box. The dipole antenna according to any one of claims 1 to 3, wherein:   5. The slit according to claim 1, wherein one or more slits for adjusting an equivalent width are provided on a side of the other conductor plate adjacent to one of the two conductor plates. Antenna.   A rectangular conductor plate serving as a radiation conductor, and a U-shaped conductor having a length and a width different from those of the conductor plate, and one side of the rectangular conductor plate in the length direction and One side of the U-shaped conductor is aligned with a straight line, and one side in the width direction of the rectangular conductor plate and the middle side of the U-shaped conductor are configured to be close to each other at a predetermined interval. A dipole antenna, wherein a feed line is connected to each of the rectangular conductor plate and the U-shaped conductor.   7. A dipole antenna according to claim 6, wherein a U-shaped conductor is used in place of the rectangular conductor plate serving as a radiation conductor.   8. The dipole antenna according to claim 6, wherein a transmitter / receiver circuit unit is disposed inside the U-shaped conductor, and power is supplied to each conductor from the transmitter / receiver circuit unit.   7. The dipole antenna according to claim 6, wherein the rectangular conductor plate and the U-shaped conductor are formed of a conductive foil of a printed board.   8. The dipole antenna according to claim 7, wherein the two rectangular conductor plates are formed of a conductive foil of a printed board.   The rectangular conductor plate is provided on one surface or the back surface of the two plates or the box that is folded by the hinge portion, and the U-shaped conductor is provided on the other surface or the back surface of the two plates or the box. The dipole antenna according to claim 6.   One of the two rectangular conductor plates is provided on one of the two plates or the box that is folded by the hinge portion, and the other of the two rectangular conductor plates is provided on the other of the two plates or the box. The dipole antenna according to claim 7, wherein the antenna is a dipole antenna.

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