JP2009124403A - Antenna unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cross dipole antenna unit whose number of components is small for easy assembling and which is light in weight. <P>SOLUTION: A first dielectric substrate 110 and second dielectric substrate 120, with antenna elements of different shapes formed on both surfaces, are combined at a cut part. Engaging parts are inserted in engaging parts of a stage 130, where a grounding pattern 130a is formed on its surface so that the center axes of the first and second dielectric substrates coincide orthogonally with each other orthogonally. Under this condition, the cross dipole antenna mounted unit 100 is fixed to the stage. The antenna elements are so formed so as not to contact each other, a feed point and a shorting point are provided to the contact point between the end part of antenna element and the stage 130. With this configuration, a cross dipole antenna of high productivity and strength is provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an antenna device, and more particularly to a cross-dipole antenna device for a wireless device in mobile communication.

  Conventional cross dipole antennas are roughly classified into two types. In the first type, four L-shaped antenna elements formed using a semi-rigid cable or the like are arranged as two pairs of dipole antennas so as to intersect at 90 °, and power is fed to the antenna element side that forms a 180 ° pair with each other. And having a structure in which the outer conductor portion is short-circuited. The second type is a structure in which antenna elements are printed on a printed circuit board, two pairs of dipole antennas are crossed at 90 ° by a combination of two printed circuit boards, and power is fed by a coaxial cable or the like. It is what has.

Among these, the antennas described in Patent Documents 1 to 3 can be referred to as the latter example. Patent Document 1 describes an antenna device in which two types of antenna elements in which an antenna pattern is formed along an end face of a plate-like dielectric are three-dimensionally crossed by combining slits on the center axes of each other. Patent Document 2 describes a cross dipole antenna in which antenna patterns having different shapes are formed on both surfaces of a dielectric substrate and two dielectric substrates are crossed at right angles. Further, Patent Document 3 describes a polarization diversity antenna in which an antenna pattern is formed on a surface of a dielectric substrate and two dielectric substrates are orthogonal to each other. It is possible to widen the beam width.
JP 2005-51575 A Japanese Patent Laid-Open No. 2001-168637 JP 2006-352293 A

However, such a conventional cross dipole antenna has the following problems.
First, it is necessary to electrically connect the required portions of the dipole antenna using four separate parts, but since the antenna elements are orthogonal, the connection is complicated and difficult. Therefore, the productivity is poor and the electrical characteristics become unstable because the connection points are likely to vary.
Furthermore, when the antenna elements are orthogonalized, the arrangement angle is determined by the accuracy of the parts and jigs or the ability of the manufacturer, so that there remains a problem in the assembling accuracy.
In view of these points, an object of the present invention is to provide an antenna device that is easy to assemble, has high productivity, and has good assembly accuracy.

  In order to achieve this object, an antenna device provided by the present invention includes a first antenna element having an electrical length of λ / 4 formed on the front surface and a first antenna element having an electrical length of λ / 4 formed on the rear surface. A substantially rectangular first dielectric substrate having two antenna elements and a plurality of fitting portions, a third antenna element having an electrical length of λ / 4 formed on the front surface, and formed on the back surface a substantially rectangular second dielectric substrate having a fourth antenna element having an electrical length of λ / 4, a plurality of fitting portions, and a pedestal for attaching the first and second dielectric substrates; Is provided. Each of the first and second dielectric substrates has a cut portion perpendicular to the long side at the center of one long side, and the pedestal is formed on the surface to which the first and second dielectric substrates are attached. A grounding short circuit pattern, a plurality of power supply portions provided near the center through the pedestal, a plurality of insertion portions for fixing the first and second dielectric substrates by inserting the fitting portions; The first dielectric substrate and the second dielectric substrate are attached to the pedestal so that the central axes coincide with each other and are orthogonal to each other by combining the cut portions with each other. The first to fourth elements are formed so as not to contact each other when the first dielectric substrate and the second dielectric substrate are combined. The first antenna element extends from the vicinity of the central axis of the first dielectric substrate toward one short side of the first dielectric substrate in parallel with the long side of the first dielectric substrate. A second antenna element comprising: a side; a second side coupled perpendicularly to the first side at one end of the first side; and a third side coupled perpendicularly to the first side in the middle of the first side Are a first side extending in parallel with the long side of the first dielectric substrate from the vicinity of the central axis of the first dielectric substrate toward the other short side of the first dielectric substrate, And a second side coupled perpendicularly to the first side at one end of the side. The third antenna element extends from the vicinity of the central axis of the second dielectric substrate toward one short side of the second dielectric substrate in parallel with the long side of the second dielectric substrate. An edge, a second edge that is coupled perpendicularly to the first edge at one end of the first edge, a third edge that is coupled perpendicularly to the second edge at one end of the second edge, and a first edge at one end of the third edge. A fourth piece coupled perpendicularly to three sides, the second side, the third side, and the fourth side form a U-shape, and the fourth antenna element is a second dielectric A first side extending in parallel with the long side of the second dielectric substrate from the vicinity of the central axis of the substrate toward the other short side of the second dielectric substrate, and a first side at one end of the first side And a second side coupled orthogonally. When the first and second dielectric substrates are attached to the pedestal, power is supplied to the contact between the power supply unit and the second side of the first antenna element and the contact between the power supply unit and the fourth side of the third antenna element. A grounding short-circuit pattern of the base, the third side of the first antenna element, the second side of the second antenna element, the second side of the third antenna element, and the second side of the fourth antenna element. A ground short-circuit point is formed at each contact point with the side.

In this antenna device, the antenna element may be a broadband element.
In this antenna device, the pedestal may be rectangular.
Further, in the antenna apparatus, the pedestal may be circular. On the other surface of the pedestal, there is a 90 ° phase circuit that shifts the phase of the signal supplied to the antenna element on the first dielectric substrate and the signal supplied to the antenna element on the second dielectric substrate by 90 °. It may be formed.

The antenna device according to the present invention can be composed of a small number of parts, and the soldering process can be minimized as compared with the prior art. Therefore, the assembly is easy and the productivity is excellent. Weight reduction can be realized. In addition, the orthogonality is high and the strength is improved as compared with the conventional antenna device. Since the pedestal and the antenna element are integrally formed, it can be easily mounted on an array antenna such as a base station antenna.
In addition, when the pedestal is made circular, the pedestal can be used as a reflecting plate by making its diameter equal to or greater than the wavelength of the operating frequency, and a 90 ° phase circuit can be provided on the pedestal. It can also be attached to a circularly polarized wave specification to provide a satellite communication antenna.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a crossed dipole antenna device according to a first embodiment of the present invention, and shows a case where (a) and (b) are viewed from different angles. As illustrated, the antenna device 100 is configured by combining a first dielectric substrate 110 and a second dielectric substrate 120 on a pedestal 130.
Of these, the first dielectric substrate 110 is shown in FIG. 2A shows the front surface 110a of the first dielectric substrate 110, and FIG. 2B shows the back surface 110b. The first dielectric substrate 110 has a substantially rectangular shape, and a notch 201 is provided at the center of one long side perpendicular to the long side. The width of the cut portion 201 is substantially the same as the thickness of the dielectric substrate. In addition, convex fitting portions 30 are formed at both ends of the other long side facing the side.

  As shown in FIG. 2A, an antenna element a1 formed by combining three sides a11, a12, and a13 is formed on the surface 110a of the first dielectric substrate 110. Each of the lengths L11 and L12 is λ / 4 in electrical length. The sides a12 and a13 are separated by, for example, about 0.05λ. On the other hand, as shown in FIG. 2B, an antenna element a2 formed by joining two sides a21 and a22 is formed on the back surface 110b of the first dielectric substrate 110, and its pattern length L13 is shown. And L14 each have an electrical length of λ / 4. The antenna elements a1 and a2 are made of metal such as copper foil.

  2A and 2B, in order to clarify the positional relationship between the antenna elements formed on the front surface 110a and the back surface 110b, the antenna elements on the surface displayed on the front side are indicated by solid lines, and the broken lines are shown. Shows the antenna element on the surface displayed on the back side. As shown in the figure, each antenna element is substantially bilaterally symmetric between the front surface and the back surface.

Next, the second dielectric substrate 120 is shown in FIG. 3A shows the front surface 120a of the second dielectric substrate 120, and FIG. 3B shows the back surface 120b. The distinction between solid and broken lines is the same as in FIG. The second dielectric substrate 120 has substantially the same shape as the first dielectric substrate 110, but the notch portion 202 and the convex fitting portion 30 are formed on the same long side. There are differences. The cut portion 202 is provided in the center of the long side in a direction perpendicular to the long side. Moreover, the fitting part 30 is formed in the both ends of a long side.
The sum of the length of the cut portion 201 of the first dielectric substrate 110 and the length of the cut portion 202 of the second dielectric substrate 120 is, for example, the same as the length of the short side of each dielectric substrate. Can do.

  As shown in FIG. 3A, an antenna element b1 including four sides b11, b12, b13, and b14 is formed on the surface 120a of the second dielectric substrate 120, and a pattern length L21 thereof is formed. And L22 each have an electrical length of λ / 4. The sides b12 and b14 are separated by, for example, about 0.05λ. On the other hand, as shown in FIG. 3B, an antenna element b2 composed of two sides b21 and b22 is formed on the back surface 120b, and the pattern lengths L23 and L24 are λ / 4 in electrical length, respectively. is there. Similarly to the antenna elements a1 and a2 shown in FIG. 2, the antenna elements b1 and b2 are also made of metal such as copper foil.

  FIG. 4 shows a pedestal 130 used for the antenna device 100. FIG. 4A shows the front surface to which the first dielectric substrate 110 and the second dielectric substrate 120 are attached, and FIG. 4B shows the back surface. A ground short-circuit pattern 130a is formed on the surface of the pedestal 130 with a copper foil or the like. The pedestal 130 has a square shape, and is provided with four insertion portions 40 in the vicinity of the end portion and two power feeding portions 50 that penetrate the pedestal 130 in the vicinity of the center.

  In this embodiment, as shown in FIG. 4, the fitting portion 40 is a long hole, and the long axis direction is provided so as to overlap two orthogonal diagonal lines of the pedestal 130. Here, the size and shape of the fitting portion 40 are not limited to those shown in the drawings, and it is sufficient that each dielectric substrate can be fixed in cooperation with the fitting portion. The fitting portion 40 is provided at a location corresponding to the position of the fitting portion of each dielectric substrate when the first and second dielectric substrates are combined and disposed on the pedestal 130.

  Such first dielectric substrate 110, second dielectric substrate 120, and pedestal 130 constitute an antenna device 100 as shown in FIG. That is, the first dielectric substrate 110 and the second dielectric substrate 120 mesh the notches 201 and 202 to form a cross-shaped three-dimensional intersection. At this time, the height of the three-dimensional intersection is equal to the length of the short sides of both dielectric substrates. Then, by inserting each fitting portion 30 of the first dielectric substrate 110 and the second dielectric substrate 120 into the fitting portion 40 of the pedestal 130, the first dielectric substrate 110 and the second dielectric substrate 120 are It is fixed to the pedestal 130 in an orthogonal state.

  5 and 6 are perspective views of the antenna 100 configured as described above. Unlike FIGS. 1A and 1B, FIGS. 5A and 5B show the front surface 110a and the back surface 110b of the first dielectric substrate 110 in the front direction. 6A and 6B show the front surface 120a and the back surface 120b of the second dielectric substrate 120 in the front direction. 7A is a top view of the antenna device 100, and FIG. 7B is a bottom view of the antenna device 100. FIG.

As shown in FIGS. 5 to 7, one side a <b> 12 of the antenna element a <b> 1 of the first dielectric substrate 110 and one side b <b> 12 of the antenna element b <b> 1 of the second dielectric substrate 120 respectively extend toward the base 130. The tip portion is in contact with the power feeding unit 50. A feed point 50 is formed at each contact.
Further, another side a13 of the antenna element a1, one side a22 of the antenna element a2, another side b14 of the antenna element b1, and one side b22 of the antenna element b2 also extend toward the pedestal 130. Shorted to ground at the contact.

  The other side a11 of the antenna element a1, the other side a21 of the antenna element a2, the other side b11 of the antenna element b1, and the other side b21 of the antenna element b2 are respectively the first dielectric substrate 110 and the second dielectric. The body substrate 120 extends in the vicinity of one of the short sides in parallel with the long side.

  In the first dielectric substrate 110 and the second dielectric substrate 120, the antenna elements a1, a2, b1, b2 on the front surface and the back surface are formed so as not to contact each other. In addition, for example, a power supply pin may be soldered to the power supply unit 50 via a coaxial cable or a microstrip line, or the antenna elements a12 and b14 may be soldered to the ground short circuit pattern 130 in the ground short circuit unit 60. That is, both feeding and short-circuiting are performed so that electrical continuity can be obtained.

  In such an antenna device 100, as described above, the antenna elements a 1, a 2, b 1, and b 2 are substantially bilaterally symmetrical on the front and back surfaces of the dielectric substrates 110 and 120. Each element forms an antenna pattern having a length of λ / 4, and power is supplied near the center on the surfaces 110a and 120a of the dielectric substrates 110 and 120. On the other hand, the back surfaces 110b and 120b of the dielectric substrates 110 and 120 are grounded to the pedestal 130 and operate as a λ / 2 dipole antenna.

  Further, on the surfaces 110a and 120a, the sides a13 and b12 are short-circuited to the pedestal 130 to form a λ / 2 detour, functioning as a balun that converts from balanced mode to unbalanced mode, and unbalanced. This prevents the antenna characteristics from being adversely affected, such as the radiation pattern and the deterioration of the VSWR characteristics.

  The effect of such an antenna device 100 is shown directly in the graphs of FIGS. FIG. 8 shows a measurement result of VSWR (Voltage Standing Wave Ratio) at a predetermined frequency of the antenna apparatus 100, and FIG. 9 shows a measurement result of isolation characteristics. Referring to FIG. 8, it can be seen that the antenna device 100 can secure a band of 10% or more with VSWR ≦ 2.0 with respect to a predetermined frequency. Further, as shown in FIG. 9, it can be seen that the isolation is also -20 dB or more, and it operates as a dipole antenna without any problem and a good result is obtained.

  By the way, in recent years, polarization diversity effects have been demanded in outdoor cellular base station antennas, and vertical / horizontal (V / H) and ± 45 ° polarization diversity are being adopted. The cross dipole antenna device 100 of the present invention can also be used for such a base station antenna.

  FIG. 10 and FIG. 11 show that a plurality of antenna devices 100 are mounted in an array on a metal ground plane 70 to form a base station antenna for polarization diversity. 10 shows an array antenna 210 for V / H polarization, and FIG. 11 shows an array antenna 220 for ± 45 ° polarization, and a plurality of antenna devices 100 are fixed to the ground plane 70 with screws or the like. Thus, it can be easily manufactured. Since the antenna device 100 can be easily formed with a small number of parts, the antennas 210 and 220 can increase productivity as compared with the conventional antenna, and have an advantage of being reduced in weight as a whole.

Next, a second embodiment of the present invention will be described.
FIG. 12 shows a cross dipole antenna device 100 ′ according to another embodiment of the present invention. As shown in the figure, the antenna device 101 has substantially the same configuration as the antenna device 100 described above, but only the shape of the antenna element is different.

  In the second dielectric substrate 121 illustrated in FIG. 12, among the sides of the antenna element b1 ′, the width of b11 ′ is wide. In addition, the shape of the antenna element is similarly changed for the first dielectric substrate (not shown) to obtain a broadband element. Thereby, VSWR ≦ 2.0 can be realized over a wider band than the antenna device 100. This is shown in FIG. The solid line represents the VSWR measurement result for the antenna device 100 according to the first embodiment, and the broken line represents the VSWR measurement result for the antenna device 100 ′ according to the second embodiment.

Subsequently, a third embodiment of the present invention will be described.
FIG. 14 is a perspective view of a cross dipole antenna device according to a third embodiment of the present invention. As in the first embodiment shown in FIG. 1, the antenna device 101 is configured by combining a first dielectric substrate 110 and a second dielectric substrate 120 on a pedestal 131. The structures of the first dielectric substrate 110 and the second dielectric substrate 120 are the same as those in the first embodiment described above.

  Here, the pedestal 131 used in the antenna device 101 is circular, unlike the first and second embodiments. This antenna device 101 is a directional antenna using a grounding short-circuit pattern 131a of copper foil on the surface of a base 131 as a reflector. Further, the signal supplied to the antenna element on the first dielectric substrate 110 and the second dielectric are provided on the back surface of the pedestal 131 like the rat race hybrid circuit shown in FIG. 15 or the branch line hybrid circuit shown in FIG. It is also possible to form a 90 ° phase circuit that shifts the phase of the signal supplied to the antenna element on the substrate 120 by 90 ° to form a circularly polarized antenna, which can be used for satellite communication.

  At this time, the diameter of the base 131 is assumed to be larger than the operating frequency λ. Also, the reference numerals P1 to P4 used in FIGS. 15 and 16 are the same as the reference numerals P1 to P4 used in the circuit diagram shown in FIG. 17 and represent port connections.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments and can be implemented in various ways. For example, in the third embodiment, a broadband element can be used as in the second embodiment.

(A) And (b) is a perspective view of the cross-dipole antenna apparatus by the 1st Example of this invention. (A) is the figure showing the surface of the 1st dielectric, and (b) is the figure showing the back of the 1st dielectric. (A) is a figure showing the surface of the 2nd dielectric, and (b) is the figure showing the back of the 2nd dielectric. (A) is the figure showing the surface of a base, (b) represents the back surface of a base. (A) And (b) is a perspective view of the cross-dipole antenna apparatus by the 1st Example of this invention. (A) And (b) is a perspective view of the cross-dipole antenna apparatus by the 1st Example of this invention. (A) is a top view of the cross dipole antenna device by the 1st example of the present invention, and (b) is a bottom view. The figure which shows the measurement result of VSWR of the cross dipole antenna apparatus by the 1st Example of this invention. The figure which shows the measurement result of the isolation characteristic of the cross dipole antenna apparatus by the 1st Example of this invention. The perspective view of the array antenna for V / H polarization | polarized-light comprised using the cross dipole antenna apparatus by the 1st Example of this invention. 1 is a perspective view of an array antenna for ± 45 ° polarization constructed using a cross dipole antenna device according to a first embodiment of the present invention. FIG. The perspective view of the cross dipole antenna device by the 2nd example of the present invention. The figure which shows the measurement result of VSWR of the cross dipole antenna apparatus by the 1st and 2nd Example of this invention. The perspective view of the antenna apparatus by the 3rd Example of this invention. The bottom view of the antenna apparatus by the 3rd Example of this invention. The bottom view of the antenna apparatus by the 3rd Example of this invention. The circuit diagram of the antenna apparatus by the 3rd Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Cross dipole antenna apparatus 110 1st dielectric substrate 110a Front surface 110b Back surface 120 2nd dielectric substrate 120a Front surface 120b Back surface 130 Base 130a Grounding short circuit pattern

Claims (5)

A first antenna element having an electrical length of λ / 4 formed on the front surface, a second antenna element having an electrical length of λ / 4 formed on the back surface, and a plurality of fitting portions. A rectangular first dielectric substrate;
A third antenna element having an electrical length of λ / 4 formed on the front surface, a fourth antenna element having an electrical length of λ / 4 formed on the back surface, and a plurality of fitting portions. A rectangular second dielectric substrate;
A pedestal for mounting the first and second dielectric substrates;
With
Each of the first and second dielectric substrates has a notch perpendicular to the long side at the center of one long side,
The pedestal is inserted with a grounding short-circuit pattern formed on a surface to which the first and second dielectric substrates are attached, a plurality of power supply portions provided near the center through the pedestal, and the fitting portion. And a plurality of insertion portions for fixing the first and second dielectric substrates,
The first dielectric substrate and the second dielectric substrate are attached to the pedestal so that their center axes coincide with each other and are orthogonal to each other by combining the cut portions with each other,
The first to fourth antenna elements are formed so as not to contact each other when the first dielectric substrate and the second dielectric substrate are combined.
The first antenna element is parallel to the long side of the first dielectric substrate from the vicinity of the central axis of the first dielectric substrate toward one short side of the first dielectric substrate. A first side that extends, a second side that is coupled perpendicularly to the first side at one end of the first side, and a third side that is coupled perpendicularly to the first side in the middle of the first side; With
The second antenna element is parallel to the long side of the first dielectric substrate from the vicinity of the central axis of the first dielectric substrate toward the other short side of the first dielectric substrate. A first side that extends, and a second side that is coupled perpendicularly to the first side at one end of the first side,
The third antenna element is parallel to the long side of the second dielectric substrate from the vicinity of the central axis of the second dielectric substrate toward one short side of the second dielectric substrate. A first side that extends, a second side that is coupled perpendicularly to the first side at one end of the first side, and a third side that is coupled perpendicularly to the second side at one end of the second side; And a fourth side that is coupled perpendicularly to the third side at one end of the third side, and the second side, the third side, and the fourth side form a U-shape. ,
The fourth antenna element is parallel to the long side of the second dielectric substrate from the vicinity of the central axis of the second dielectric substrate toward the other short side of the second dielectric substrate. A first side that extends, and a second side that is coupled perpendicularly to the first side at one end of the first side,
When the first and second dielectric substrates are attached to the pedestal, the contact between the power feeding unit and the second side of the first antenna element and the fourth of the power feeding unit and the third antenna element. A feeding point is provided at the contact with the side,
The ground short-circuit pattern of the pedestal and the third side of the first antenna element, the second side of the second antenna element, the second side of the third antenna element, and the second side of the fourth antenna element A grounding short-circuit point is formed at each contact point with two sides. The antenna device according to claim 1,
The antenna device according to claim 1, wherein the pedestal is rectangular. The antenna device according to claim 1,
The antenna device according to claim 1, wherein the base is circular. The antenna device according to claim 3, wherein
On the other surface of the pedestal, the phase of the signal supplied to the antenna element on the first dielectric substrate and the signal supplied to the antenna element on the second dielectric substrate are shifted by 90 °. An antenna device, wherein a phase circuit is formed. The antenna device according to any one of claims 1 to 4,
The antenna apparatus according to claim 1, wherein the first to fourth antenna elements are broadband elements.

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