JP2007295277A - Antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna device capable of reducing the beam width without increasing the shape.
SOLUTION: First and second dipole elements (31, 41) arranged in a horizontal direction at a predetermined interval in a horizontally oriented form are provided. In the first and second dipole elements (31, 41), the lengths of the element conductors (31a, 41a) located outside are set larger than the lengths of the element conductors (31b, 41b) located inside. .
[Selection] Figure 1

Description

  The present invention relates to an antenna device, and more particularly to an antenna device suitable for application to a mobile communication base station.

  In mobile communication, in order to improve frequency utilization efficiency, an area covered by one base station is divided into sector sectors. Thus, in order to divide the rear zone into a fan shape, it is necessary to use a directional antenna device that radiates radio waves only in a desired fan-shaped range as an antenna device for a base station.

  Therefore, in the 6-sector zone configuration, an antenna device having a horizontal beam width (60 ° beam) corresponding to the sector division angle (60 °) is used. However, as the number of users increases, the subscriber capacity increases. For the purpose of increasing, research has been conducted to make the beam width of the horizontal plane of the base station antenna apparatus 45 ° (for example, see Non-Patent Document 1).

(Reiko Kimura, Keizo Naga, Yoshio Ebine, “Directional control of a 60 ° beam antenna in the horizontal plane by placing metal conductors close together” IEICE Technical Report, AP2004-47, pp, 37-42, SAT2004-45)

In order to reduce the beam width in the horizontal plane of the horizontally polarized antenna device to 45 °, for example, two dipole elements having a length of about 0.5λ ₀ (λ ₀ is the wavelength of the center frequency of the used frequency band) are used. it is necessary to sequence at a聞隔about 0.72Ramuda ₀ in the horizontal direction, the shape of the antenna device is increased.
In general, the antenna device is housed in a dielectric cover assuming that it is installed outdoors. In order to reduce the wind pressure load, a cylindrical cover is often used as the dielectric cover. As described above, the shape of the antenna device is increased, the dielectric cover requires diameter large as in the above example, the diameter will be using those 1.21Ramuda ₀ or more.

  An antenna device housed in a cylindrical cover with a large diameter hinders simplification of base station facilities such as the upper part of a steel tower, and also increases wind pressure load. Therefore, in order to reduce the size of the horizontally polarized antenna, it is conceivable to reduce the arrangement interval of the two dipole elements. However, as is clear from FIG. 19 showing the relationship between the arrangement interval of the dipole elements and the beam width in the horizontal plane, when the interval between the dipole elements is reduced, the beam width is increased to obtain a 45 ° beam in the horizontal plane. become unable.

  The present invention has been made in view of such a situation, and an object thereof is to provide an antenna device capable of reducing the beam width without increasing the shape.

  The antenna device according to the present invention includes first and second dipole elements arranged in a horizontal direction at a predetermined interval in a horizontal direction. In the first and second dipole elements, the length of the element conductor located on the outside is set larger than the length of the element conductor located on the inside, thereby achieving the above object.

  The first and second dipole elements can be formed on the same or separate dielectric substrates. In this case, the element conductor located on the outside and the element conductor located on the inside of the first and second dipole elements may be bent so as to form an umbrella shape. And the front-end | tip part of the element conductor located in the said outer side can be formed in a curve shape so that the inner peripheral surface of a dielectric cover may be followed. Furthermore, a power supply system including a balun may be formed on the dielectric substrate.

The antenna device can be arrayed by arranging a plurality of antenna devices.
Also, three or more dipole elements formed on the dielectric substrate so as to be arranged in the horizontal direction at a predetermined interval in a vertically oriented form, and the dielectric in a form branched from the branch point in the arrangement direction of the dipole elements. A vertical line formed on a substrate and having at least one or more dipole elements connected to one branch line and at least two or more dipole elements connected to the other branch line It is also possible to configure a vertical / horizontal polarization antenna device by combining a polarization antenna device with the antenna device.
The vertical / horizontal polarization shared antenna apparatus can also be arrayed by arranging a plurality of antenna apparatuses.
Of course, each antenna device can also be adjusted in directivity by providing a reflector.

  The antenna device according to the present invention can realize both reduction in beam width in the horizontal plane and miniaturization. Therefore, it is effective as an antenna device used in a mobile communication base station.

FIG. 1 is an elevational view showing a first embodiment of an antenna device according to the present invention. The antenna device 10 includes two dipole antenna portions 30 and 40 printed on a dielectric substrate 20.
One dipole antenna unit 30 includes a dipole element 31 and ground conductors 32 a and 32 b formed on one surface of the dielectric substrate 20, and a feed line conductor 33 printed on the other surface of the dielectric substrate 20. ing.

The dipole element 31 includes element conductors 31a and 31b, and is formed along one end (the upper end in the drawing) of the dielectric substrate 20. Element conductors 31a, 31b are different in length from each other, in the present embodiment, the outer element conductor 31a of length L _a of about 0.21λ ₀ (λ ₀ is the center of the frequency band of the (left in the drawing) the wavelength) of the frequency and the length L _b of the element conductor 31b of the inner (right in the drawing) are respectively set to about 0.19λ _0.
The ground conductors 32a and 32b extend in a direction (downward in the drawing) perpendicular to the element conductors 31a and 31b, respectively, starting from the feeding points of the element conductors 31a and 31b. That is, the ground conductors 32a and 32b extend to the other end (lower end in the drawing) of the dielectric substrate 20 so that a slit 34 having a length of about 0.25λ is formed between them.

The feed line conductor 33 extends from the lower end of the dielectric substrate 20 to the back of the feeding point portion of the element conductor 31b in a form facing the back surface of the ground conductor 32b, and further, the portion from there is bent to the element conductor 31a side. It is formed so as to extend toward the lower end of the dielectric substrate 20 after traversing the upper part of the slit 34. That is, the feed line conductor 33 has a substantially inverted U shape that folds with the central portion of the dipole element 31 as the top. In the feeding line conductor 33, the length leading to the tip from the feeding point site element conductor 31b is set to about 0.25 [lambda _0. Note that the front half of the feed line conductor 33 may extend along the element conductor 31a without being folded back. In this case, the feed line conductor 33 has an L shape.

The other dipole antenna section 40 includes a dipole element 41, ground conductors 32a and 32b, a feed line conductor 33 and a slit 34 corresponding to the dipole element 31 of the dipole antenna section 30, ground conductors 42a and 42b, a feed line conductor 43 and a slit. 44 is formed on the dielectric substrate 20 and is provided at a distance of D from the dipole antenna 30 in the horizontal direction. In this embodiment, the distance D is set to about 0.5 [lambda _0.
The element conductors 41a and 41b of the dipole element 41 are positioned symmetrically with respect to the element conductors 31a and 31b of the dipole element 31, and therefore, the long element conductor 41a is positioned outside (the right end side of the dielectric substrate 20). In addition, the short-side element conductor 41b is located inside (on the first dipole antenna unit 30 side).

  The lower end of the dielectric substrate 20 is vertically brought into contact with a power supply dielectric substrate (not shown). The base ends of the feed line conductors 33 and 43 are connected to the two distribution feed lines printed on the dielectric substrate for feeding, and the ground conductor is connected to the ground conductor printed on the dielectric substrate. 32a, 32b and 42a, 42b are connected. In this way, the dipole antenna units 30 and 40 are fed via the dielectric substrate for feeding.

  In the dipole antenna unit 30 in this embodiment, since the ground conductors 32a and 32b are separated by the slits 34, the directions of the currents flowing through the ground conductors 32a and 32b are reversed. Since no current flows through the base ends of the ground conductors 32a and 32b, the power supply system including the ground conductors 32a and 32b and the power supply line conductor 33 includes a balun (balanced / unbalanced converter) that converts the potential. Will be included. The same applies to the corresponding feeding system of the other dipole antenna unit 40. The power feeding system may have a cross power feeding configuration instead of an open balun configuration.

  Instead of providing the dipole antenna portions 30 and 40 on one dielectric substrate 20, these may be provided on individual dielectric substrates. If necessary, a reflector (not shown) having a flat shape or a U-shaped cross-section with both ends raised to the dipole antenna portions 30 and 40 is disposed on the back of the dielectric substrate for power supply. can do.

Next, the operation of the antenna device 10 according to this embodiment will be described. The antenna device 10 is mounted in a form in which the dielectric substrate 20 is horizontal so as to transmit and receive horizontally polarized waves.
FIG. 2 shows, as a comparative example, the arrangement interval D of the dipole antenna portions 30 and 40 is set to D≈0.5λ ₀ , and the element conductor lengths L _a and L _b are set to L _a = L _b ≈0.25λ ₀ . The combined directivity in the horizontal plane of the set antenna device is illustrated, and FIGS. 3 and 4 illustrate the amplitude directivity and the phase directivity in the horizontal plane of each of the dipole antenna units 30 and 40 under the same conditions. Yes.
Further, FIG. 5, the die arrangement interval D of the pole antenna portion 30 and 40 is set to D ≒ 0.5 [lambda, the element conductor length L _a, a _{L b L a ≒ 0.21λ 0,} L b ≒ 0. It illustrates the combined directivity of the horizontal plane of the antenna device 10 according to the present embodiment is set to 19Ramuda _0, 6 and 7, the amplitude directivity of the dipole antenna portion 30, 40 alone in the horizontal plane under the same conditions And phase directivity are respectively illustrated.
3, 4, 6, and 7, the characteristic of the dipole antenna unit 30 is indicated by a solid line, and the characteristic of the dipole antenna unit 40 is indicated by a dotted line.

Contrast As is apparent from FIGS. 4 and 7, according element conductor length L _a, the L _b in the antenna device 10 according to the present embodiment is set to L _a> L _b, the left and right dipole antenna portion 30 and 40 In the vicinity of the main beam direction is larger than that in the antenna device according to the comparative example.
Since the combined directivity changes depending on the amplitude directivity and phase directivity of each dipole antenna unit 30, 40, when the amplitude value of each dipole antenna unit 30, 40 is similar at a certain angle, Its synthesis directivity is weakened. Therefore, the antenna device according to the present embodiment having the amplitude directivity of FIG. 7 and the phase directivity of FIG. 7 as compared with the antenna device of the comparative example having the amplitude directivity of FIG. 4 and the phase directivity of FIG. In the case of 10, the beam width of the combined directivity of each antenna unit becomes narrower. That is, the beam width for the comparative example is about 53 ° (see FIG. 2), but the beam width of the antenna device according to the present embodiment is about 45 ° (see FIG. 5).

As is clear from the above description, according to the antenna device 10 according to the present embodiment, a narrow beam width can be obtained without increasing the arrangement interval D of the dipole antenna units 30 and 40, so that a small diameter (for example, , About 1.02λ). This is advantageous in simplifying the base station equipment and reducing the wind pressure load.
Further, according to the antenna device 10 according to the present embodiment, the element conductor length L _a, the phase directional changes in the dipole antenna portion 30 and 40 by adjusting the L _b, about the specific band as shown in FIG. 8 25 % (<1.5) satisfying a good VSWR (standing wave ratio) characteristic, that is, a wide band can be achieved.

It should be noted that due to the influence of the mounting means (brackets, screws, etc.) of the dielectric substrate 20 and connection cables, the electrical characteristics of the dipole antenna portions 30 and 40 become asymmetrical, and the directivity in the horizontal plane is distorted. There is a fear. However, such a problem is solved by individually adjusting the element conductor lengths L _a and L _b of the dipole elements 31 and 41 in advance so that the distortion in the horizontal plane directivity is corrected.

FIG. 9 shows a second embodiment of the antenna device according to the present invention. The antenna device 50 according to this embodiment has a configuration in which dipole antenna portions 70 and 80 are provided on a dielectric substrate 60.
The dipole antenna portions 70 and 80 are different from the dipole elements 31 and 41 of the dipole antenna portions 30 and 40 shown in FIG. That is, one dipole element 71 is bent to the lower end side of the dielectric substrate 60 so that the outer element conductor 71a and the inner element conductor 71b constituting the dipole element 71 form an umbrella shape. The conductors 81a and 81b are also bent in the same form. The outer element conductors 71a and 81a are formed with curved outer edges.
The dielectric substrate 60 has its corners shaped so as to follow the outer edge shape of the element conductors 71a and 81a.

In this embodiment, the bending angle θ of the element conductors 71a, 71b and 81a, 81b is set to 30 °, but is not limited to this. Further, in this embodiment, the outer element conductor 71a, to the length L _a of about 0.21λ ₀ of 81a, inner element conductor 71b, the length L _b is about 0.19Ramuda ₀ of 81b, the dipole antenna unit arrangement intervals of 70 and 80 are respectively set to approximately 0.5 [lambda _0. Note that the lengths L _a and L _b are projection lengths on horizontal lines on the paper surface of FIG.
The dipole antenna units 70 and 80 have the same configuration as the dipole antenna units 30 and 40 shown in FIG. 1 except that the dipole elements 71 and 81 are formed as described above. Therefore, the reference numerals corresponding to the reference numerals shown in FIG.

The antenna device 50 according to the second embodiment having the above-described configuration is, like the antenna device 10 according to the first embodiment, two distributions that are printed on a dielectric substrate for power supply (not shown). Power can be supplied via a power supply line.
Since this antenna device 50 operates in the same manner as the antenna device 10, the same effects as the device 10 (such as a narrowing of the beam width due to a change in phase directivity) can be achieved.

The antenna device 50 is also accommodated in a cylindrical dielectric cover 90 (radome) as shown in FIG. 10, and at this time, the element conductors 71a and 81a outside the dipole antenna portions 70 and 80 are bent in an umbrella shape. In addition, since the outer edge is formed in a curved shape, the element conductors 71a and 81a can be brought close to the inner peripheral surface of the dielectric cover 90. As described above, when the element conductors 71a and 81a are brought close to the inner peripheral surface of the dielectric cover 90, the dielectric forming the cover 90 has an effect of making the element conductors 71a and 81a appear electrically large. An effect equivalent to extending the element conductors 71a and 81a can be obtained. This means that the element conductor 71a, the length L _a of 81a and shorter than the length (about 0.21λ _0), can be further reduced the size of the dielectric cover 90.

In addition, when the attachment means (a bracket, a screw, etc.) of the dielectric substrate 60 and the connection cable affect the characteristics of the dipole antenna portions 30 and 40, the degree of influence on each of the dipole antenna portions 30 and 40 is affected. Accordingly, the length of one or both of the element conductors 71a and 81a can be finely adjusted as appropriate so that the influence is removed.
Further, instead of providing the dipole antenna portions 70 and 80 on one dielectric substrate 20, these may be provided on individual dielectric substrates. If necessary, a reflector (not shown) having a flat shape or a U-shaped cross section with both ends raised to the dipole antenna portions 30 and 40 side is provided on the back of the dielectric substrate for power supply. can do.

The antenna device 10 shown in FIG. 1 and the antenna device 50 shown in FIG. 2 can be arrayed, and FIG. 11 shows an appropriate number (three in this example) of the latter antenna devices 50 at predetermined intervals. 1 shows an array configuration antenna apparatus 100 according to an embodiment of the present invention arranged in parallel.
The array antenna apparatus 100 includes a feeding dielectric substrate 110 on which a distribution feeding line (not shown) is printed, and individual antenna devices 50 are erected on the feeding dielectric substrate 110. Therefore, the individual antenna devices 50 are fed simultaneously through the distribution feed line. A reflector 120 is disposed on the back of the power supply dielectric substrate 110 as necessary. The reflection plate 120 has sub-reflection plates 20a raised at both ends.

The antenna device 10 shown in FIG. 1 and the antenna device 50 for horizontal polarization shown in FIG. 9 can be combined with the antenna device for vertical polarization in order to form a dual-polarization antenna device. FIG. 12 shows a dual-polarization antenna device 140 according to an embodiment of the present invention, in which the vertically polarized antenna device 130 is combined with the horizontally polarized antenna device 50 shown in FIG. The vertically polarized antenna device 130 is disposed at a position approximately 0.325λ ₀ away from the horizontally polarized antenna device 50 in the vertical direction (direction perpendicular to the dielectric substrate 60 of the antenna device 50).

The vertically polarized antenna device 130 includes dielectric substrates 150 and 160. On the dielectric substrate 150, four dipole elements 151 to 154 and a feed line 155 are printed. On the dielectric substrate 160, a feed line 161 (not shown) is printed.
Dielectric substrate 150 is in vertical contact with dielectric substrate 60 in such a manner that the longitudinal axis of dipole elements 151-154 is orthogonal to dielectric substrate 60 of antenna device 50.

The dipole elements 151 to 154 are arranged in parallel to each other. Among these, the outer dipole elements 151 and 154 have a length of about λ _a / 2, and the inner dipole elements 152 and 153 have a length of about λ _a / 2. Each is set to about λ _b / 2. λ _a is the wavelength of the frequency f _a between the center frequency f ₀ and the lower limit frequency 0.87f ₀ when the lower limit frequency of the used frequency band is 0.87f ₀ and the upper limit frequency is 1.13f ₀ . Λ _a is the wavelength of the frequency f _b between the center frequency f ₀ and the upper limit frequency 1.13f ₀ .

  One element conductors 151 a and 154 a of the outer dipole elements 151 and 154 and the other element conductors 151 b and 154 b are formed on the front surface and the back surface of the dielectric substrate 150, respectively. In addition, one element conductor 152a, 153a and the other element conductor 151b, 154b of the inner dipole elements 152, 153 are formed on the back surface and the front surface of the dielectric substrate 150, respectively.

The feed line 155 is composed of mutually opposing line conductors printed on the front and back surfaces of the dielectric substrate 150, and these line conductors are connected to the dipole elements 151 and 152 and the dipole elements 153 and 154 from the branch point 156, respectively. Two branches.
The branch line conductor on the surface side extending toward the dipole elements 151 and 152 is connected to the feeding point of the element conductors 151a and 152b, and the branch line conductor on the surface side extending toward the dipole elements 153 and 154 is connected to the element conductor. It is connected to the feeding points of 153b and 154a. On the other hand, the backside branch line conductor extending to the dipole elements 151 and 152 is connected to the feeding point of the element conductors 151b and 152a, and the backside branch line conductor extending to the dipole elements 153 and 154 is an element conductor. It is connected to the feeding points of 153a and 154b.

The outer dipole elements 151 and 154 and the inner dipole elements 152 and 153 are located symmetrically with respect to the branch point 156, respectively. In order to set the horizontal plane beam width to about 45 °, the distance between the outer dipole elements 151 and 154 is set to about 0.84λ ₀ , and the distance between the inner dipole elements 152 and 153 is set to about 0.42λ _0. ing. Therefore, the interval spacing and dipole elements 153 and 154 of the dipole elements 151 and 152 are each about 0.21λ _0.

  The dielectric substrate 160 is in contact with the center of the back surface of the dielectric substrate 150 in a form orthogonal to the dielectric substrate 150 and along the dipole elements 151 to 154. On the dielectric substrate 160, a feed line (not shown) connected to the branch point 156 of the feed line 155 is printed in the vertical direction in FIG. In the present embodiment, a feed line of the dielectric substrate 160 having a characteristic impedance of 50Ω is used.

  This dual-polarized antenna device 140 further includes a dielectric substrate 170 facing the dielectric substrate 150 with the dielectric substrate 160 interposed therebetween, and a reflection plate 180 provided on the back of the dielectric substrate 170. The dielectric substrate 160 is in contact with the dielectric substrate 170, and the dielectric substrate 60 of the antenna device 50 is also in contact therewith. A feed line (not shown) is printed on the dielectric substrate 170, and the antenna devices 50 and 130 are fed through the feed line. The reflection plate 180 is positioned at the back of both antenna devices 50 and 130, and sub-reflection plates 180a are formed upright at both ends thereof.

  By the way, in an antenna apparatus applied to mobile communication, as a branching unit when converting one input signal into two or more signals, a length of about ¼ of the wavelength of the center frequency of the used fractional band is appropriate. A power divider with an impedance matching circuit with characteristic impedance is used. The bandwidth of the ¼ wavelength impedance matching circuit is designed to be about VSWR 1.1 or less in order to keep the VSWR characteristic of the antenna device good. Since the specific bandwidth of the single-stage quarter-wave matching circuit is about 17%, a two-stage quarter-wave matching circuit must be used to achieve the target specific bandwidth of about 25%. .

However, when a two-quarter wavelength matching circuit is used, the length of the matching circuit in each branch line is about 1 / 2λ ₀ , so the total length of the matching circuit in the line including each branch line is equivalent to 1λ _0. It also becomes. It is practically difficult to reliably insert such a matching circuit. In particular, in the antenna device 130 having the structure shown in FIG. 12, depending on the arrangement form of the dipole elements 151 to 154, it is possible that the one-quarter wavelength matching circuit cannot be configured in the feed line 155.

Therefore, in the antenna device 130, the feed line 155 is configured so that the characteristic impedances of the one and the other branch line conductors branched from the branch point 156 of the feed line 155 are fixed to the characteristic impedances of the branch points 156, respectively. Yes.
That is, the feed line 155 is configured such that the characteristic impedance of the one and the other branch line conductors is approximately twice the characteristic impedance of the feed line provided on the dielectric substrate 160. Therefore, when the characteristic impedance of the feed line of the dielectric substrate 160 is 50Ω, the characteristic impedances of one and the other branch line conductors of the feed line 155 are fixed to about 100Ω, respectively.
Thereby, branch feeding to the arrayed dipole elements 151 to 154 becomes possible without using a quarter wavelength matching circuit.

The vertically polarized antenna device 130 having such a configuration excites each of the dipole elements 151 to 154 by inputting a high-frequency signal having a center frequency f ₀ through a feed line provided on the dielectric substrate 160. Can do.
According to the antenna device 130, since the dipole elements 151 to 154 are arranged in parallel (arrayed) in the horizontal direction, the side lobe level is set despite the fact that the horizontal plane has a narrow beam width (about 45 °). It is possible to reduce the size without causing deterioration. The reason will be described below.

A conventional antenna device that is not arrayed has a configuration in accordance with a configuration in which the dipole elements 152 and 153 of the antenna device 130 are removed. This conventional antenna device is also provided with a reflector to reduce the back lobe. However, when the distance between the two dipole elements is widened to reduce the beam width of the horizontal plane to, for example, about 45 °, the side lobe level is reduced. It causes degradation and increases the overall size of the antenna.
On the other hand, according to the antenna device 130, since the beam width in the horizontal plane is narrowed by arraying in the horizontal direction, the side lobe level does not depend on the size of the reflector. Therefore, even if a reflector having a small area as shown in the figure is used, the side lobe level does not deteriorate, and as a result, it is possible to reduce the size even when the beam width is narrowed.

Further, according to the antenna device 130, as described above, the characteristic impedance of each branch line conductor of the feed line 155 is set to about twice the characteristic impedance of the feed line provided on the dielectric substrate 160. The feed line 155 does not have frequency characteristics and thus has a wide band. In other words, it is possible to realize a good VSWR (standing wave ratio) characteristic satisfying a specific bandwidth of about 25% (<1.5) as shown in FIG.
The antenna device 130 is configured so that the dipole elements 151 and 154 and the dipole elements 152 and 153 resonate at the intermediate frequencies f _a and f _b , respectively, which also contributes to a wider band. That is, according to this configuration, a wider band is obtained than when all the dipole elements 151 to 154 are resonated at the center frequency f ₀ . Of course, even if all the dipole elements 151 to 154 are made to resonate at the center frequency f ₀ , it is possible to obtain a practically sufficient broadband property.

  Depending on the desired beam width, the arrangement number of the dipole elements 151 to 154 may be changed. In that case, the resonance lengths of these dipole elements are set so as to match the number of the arrays. Further, it is not necessary to provide the same number of dipole elements on one and the other branch feeding conductors around the branch point 156 of the feeding line 155. For example, two dipole elements are provided on one branch feeding conductor and the other branch feeding conductor is provided. It is also possible to provide three dipole elements on the feed conductor. Further, the vertically polarized antenna device 130 is configured to feed the outer dipole elements 151 and 154 and the inner dipole elements 152 and 153 in opposite phases, so that these are fed in the same phase. It may be configured.

FIG. 14 shows that the vertically polarized antenna device 130 has a horizontal plane directivity as shown in FIG. 14 at a frequency of 0.87f ₀ , and a horizontal plane directivity as shown in FIG. 15 at a frequency of 1.13f ₀ . . In each figure, the solid line is based on the calculated value, and the dotted line is based on the actually measured value. As is apparent from these drawings, according to the antenna device 130, the beam width of the horizontal plane for each frequency can be reduced to around 45 °.
On the other hand, FIGS. 16 and 17 show the directivity in the horizontal plane of the horizontally polarized antenna device 50 corresponding to FIGS. 15 and 16, respectively. As can be seen from these figures, this horizontally polarized antenna device 50 can also narrow the horizontal plane beam width for each of the above frequencies to near 45 °.
Therefore, the polarization sharing antenna device 140 according to this embodiment, which is a combination of the antenna devices 50 and 130, is suitable as a polarization diversity antenna device applied to a base station for mobile communication.

FIG. 18 shows an array configuration antenna apparatus 200 according to an embodiment of the present invention in which an appropriate number (three in this example) of the dual-polarization antenna apparatuses 140 are arranged.
This array configuration antenna device 200 has a structure in which are arranged at approximately 0.65Ramuda ₀ intervals each antenna unit 140 vertically (perpendicular to the dielectric substrate 60 of the antenna device 50), and, in FIG. 12 A dielectric substrate 210 and a reflective plate 220 corresponding to the dielectric substrate 170 and the reflective plate 180 shown are provided.

1 is an elevation view showing an antenna device according to a first embodiment of the present invention. It is a graph which shows the synthetic | combination directivity of the antenna apparatus which concerns on a comparative example. It is a graph which shows the amplitude directivity of each antenna part of the antenna apparatus which concerns on a comparative example. It is a graph which shows the phase directivity of each antenna part of the antenna apparatus which concerns on a comparative example. It is a graph which shows the synthetic | combination directivity of the antenna apparatus of FIG. It is a graph which shows the amplitude directivity of each antenna part of the antenna apparatus of FIG. It is a graph which shows the phase directivity of each antenna part of the antenna apparatus of FIG. It is a graph which shows the VSWR characteristic of the antenna apparatus of FIG. It is an elevational view showing a second embodiment of the antenna device according to the present invention. FIG. 10 is a plan view showing a form of mounting the antenna device of FIG. 9 in a dielectric cover. It is a perspective view which shows the antenna apparatus of an array structure using the antenna apparatus of FIG. FIG. 10 is a perspective view showing a dual polarization antenna device incorporating the antenna device of FIG. 9. 13 is a graph showing VSWR characteristics of a vertically polarized antenna device in the antenna device of FIG. It is a graph which shows the directivity in a horizontal surface about the predetermined lower limit frequency of the said antenna device for vertically polarized waves. It is a graph which shows the directivity in a horizontal surface about the predetermined | prescribed upper limit frequency of the said antenna device for vertically polarized waves. It is a graph which shows the directivity in a horizontal surface about the predetermined lower limit frequency of the antenna apparatus for horizontal polarization in the antenna apparatus of FIG. It is a graph which shows the directivity in a horizontal surface about the predetermined | prescribed upper limit frequency of the said antenna device for horizontal polarization. It is a perspective view which shows the antenna apparatus of an array structure using the antenna apparatus of FIG. It is a graph which shows the relationship between the arrangement space | interval of a dipole element, and the beam width in a horizontal surface.

Explanation of symbols

10, 50, 100, 200 Antenna device 31, 41, 71, 81 Dipole element 30, 40, 70, 80 Antenna portion 90 Dielectric cover 120, 180, 220 Reflector

Claims (9)

First and second dipole elements arranged in a horizontal direction at a predetermined interval in a horizontal direction,
In the antenna device, the first and second dipole elements are set such that the length of the element conductor located on the outside is set larger than the length of the element conductor located on the inside.   2. The antenna device according to claim 1, wherein the first and second dipole elements are formed on the same or separate dielectric substrates.   3. The antenna according to claim 2, wherein the outer element conductor and the inner element conductor of the first and second dipole elements are bent so as to form an umbrella shape. 4. apparatus.   The antenna device according to claim 3, wherein a tip portion of the element conductor located on the outside is formed in a curved shape along the inner peripheral surface of the dielectric cover.   The antenna device according to claim 2, wherein a feed system including a balun is formed on the dielectric substrate.   6. An antenna device comprising a plurality of antenna devices according to claim 1 arranged in an array.   Three or more dipole elements formed on the dielectric substrate so as to be arranged at a predetermined interval in the horizontal direction in a vertically oriented form, and on the dielectric substrate in a form branched from the branch point in the arrangement direction of the dipole elements. And a feed line in which at least one dipole element is connected to one branch line and at least two dipole elements are connected to the other branch line. The antenna apparatus according to claim 2, wherein the antenna apparatus is combined.   An antenna device comprising a plurality of antenna devices according to claim 7 arranged in an array.   The antenna device according to claim 1, further comprising a reflector.

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