JP2005223836A - Slot feeding antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a slot feeding frequency shared antenna which enhances a polarized diversity effect by improving an intersecting polarized identifying degree. <P>SOLUTION: In a slot feeding antenna 1, a plurality of antenna elements 2 and 6 are placed in a longitudinal direction on a narrow piece of printed board 40, and metal boards 51 and 52 are placed opposed on both sides of a widthwise direction of the printed board 40 of the antenna elements 2 and 6, which are sandwiched between the metal boards 51 and 52. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an antenna, and more particularly to a base station antenna in mobile radio communication.

  Conventionally, in mobile communication, a phenomenon called fading, in which received power of electromagnetic waves fluctuates due to movement of a mobile station, has been a problem. As one of the measures to reduce this fading, a diversity method is known in which a plurality of antennas are used to simultaneously receive signals from the plurality of antennas, and a received signal from the antenna having the stronger reception power is used for communication. Yes.

  Typical examples of this diversity method include a space diversity method, a polarization diversity method, a directivity diversity method, a frequency diversity method, a time diversity method, and the like.

  In particular, a polarization diversity system that uses two polarized antennas in a single housing has been widely studied (see, for example, Patent Document 1).

  In the polarization diversity antenna, the polarization diversity effect improves as the cross polarization discrimination degree increases. An example in which the cross polarization discrimination degree is improved is disclosed in Patent Document 2. This is an example in which the cross-polarization discrimination is improved by making the parasitic elements used for the diversity antenna cross or substantially cross in a ± 45 ° polarization diversity antenna.

JP 2003-46326 A Japanese Patent Application No. 2002-114970

  However, the mobile radio communication base station antenna is realized as an array antenna in which several to tens of antenna elements are arranged. In this case, when viewed from the antenna element, there is an adjacent antenna element in the longitudinal direction of the antenna, but there is no adjacent antenna element in the width direction of the antenna, and the symmetry of the antenna is lost. . For this reason, there is a problem in that the cross polarization discrimination is deteriorated due to the influence of adjacent antenna elements.

  Therefore, an object of the present invention is to provide a slot-fed frequency sharing antenna having a high polarization diversity effect with excellent cross polarization discrimination.

  The present invention has been devised to achieve the above object, and the first invention is that a plurality of antenna elements are arranged along a longitudinal direction on an elongated printed board, and the printed board of each antenna element is arranged. 1 is a slot-fed antenna in which a metal plate is placed on both sides in the width direction of the antenna element so as to face each other.

  In the second invention, each of the antenna elements is a polarization diversity antenna element.

  According to a third aspect of the present invention, the polarization diversity antenna element is a first polarization diversity antenna element, and both longitudinal sides of the first polarization diversity antenna element or between the longitudinal directions of the first polarization diversity antenna element. A plurality of second polarization diversity antenna elements are arranged in the longitudinal direction of the printed circuit board, and second metal plates are arranged on both sides of the printed circuit board in the width direction of each of the second polarization diversity antenna elements. is there.

  According to a fourth aspect of the present invention, the first polarization diversity antenna element has two slots formed on the printed circuit board and orthogonal to each other at the center, and each slot on the back side of the printed circuit board is orthogonal to each other. Formed with two microstrip lines for feeding and two conductor patterns orthogonal to each other provided in parallel with the slot on two or more second printed boards parallel to the printed board The passive element is provided.

  According to a fifth aspect of the present invention, the second polarization diversity antenna element includes two second-sized slots formed on the printed board and orthogonal to each other at the center, and on the back side of the printed board. Two second power-feeding microstrip lines formed so as to be orthogonal to the second-sized slot, and the second printed circuit board on the two or more third printed boards parallel to the printed board. And a second parasitic element formed of two conductor patterns orthogonal to each other provided in parallel with the size slot.

  In a sixth aspect of the present invention, the metal plate is formed to be bent with a size corresponding to the polarization diversity antenna element, and the second metal plate is a size corresponding to the second polarization diversity antenna element. It is bent and formed.

  According to a seventh aspect of the present invention, the second metal plate includes a metal plate element formed by bending, a mounting portion formed by bending and fixed to a printed circuit board, the metal element and the mounting portion. And a spacer that is coupled and fixed.

  In an eighth aspect of the invention, the metal plate element is bent along the longitudinal direction of an elongated plate and formed in an L shape.

  In a ninth invention, the metal plate element has one or more cuts on one side of the L shape.

  According to the present invention, it is possible to obtain a slot-fed frequency sharing antenna having a high polarization diversity effect with excellent cross polarization discrimination.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings.

  FIG. 1 is a perspective view showing an overview of a slot-fed antenna according to a preferred embodiment of the present invention. FIG. 2 is a front view of a slot-fed antenna according to a preferred embodiment of the present invention.

  As shown in FIGS. 1 and 2, the slot-fed antenna 1 has a plurality of first polarization diversity antenna elements 2 arranged along the longitudinal direction on an elongated printed board 40, and each first polarization This is a polarization diversity antenna in which metal plates 51 are arranged on both sides in the width direction of the printed circuit board 40 of the diversity antenna element 2.

  The slot-fed antenna 1 includes a plurality of second polarization diversity antenna elements 6 arranged in the longitudinal direction of the printed circuit board 40 on both sides in the longitudinal direction of the first polarization diversity antenna element 2 or the first polarization diversity antenna 1. A plurality of second polarization diversity antenna elements 6 are arranged in the longitudinal direction of the printed circuit board 40 between the longitudinal directions of the antenna elements 2, and both widthwise sides of the printed circuit board 40 of each of the second polarization diversity antenna elements 6. In addition, the second metal plate 52 is a slot feeding type frequency sharing antenna capable of transmitting and receiving different frequencies.

  The first polarization diversity antenna element 2 includes a cross-shaped slot 3 (shown in FIG. 3) formed on the printed board 40 and formed by two slots orthogonal to each other at the center, and the printed board 40. On the back side where the slots 3 are formed, two power supply microstrip lines (not shown) formed so as to be orthogonal to the respective slots 3 and two or more second printed boards 22 parallel to the printed board 40 And a parasitic element 22a formed by two conductor patterns orthogonal to each other provided in parallel with the slot 3 and a spacer 28 for fixing the second printed circuit board 22 on the printed circuit board 40. Configured.

  A metal plate 51 formed in a size corresponding to the first polarization diversity antenna element 2 is arranged on both sides in the width direction of the printed circuit board 40 of each first polarization diversity antenna element 2. Yes.

  The first polarization diversity antenna element 2 and the metal plate 51 constitute a polarization antenna element for a low frequency.

  A slot 3 and a slot 35 are formed in the printed circuit board 40 as shown in FIG. The slot 3 and the slot 35 are provided with a conductive material (for example, copper) foil (thin film) on the surface of the printed circuit board 40 made of a dielectric material, and a part of the conductive material is removed by processing such as etching. It is formed by. These slots 3 are composed of two slots 3 a and 3 b that are orthogonal to each other at the center, and form a part of the first polarization diversity antenna element 2. The slot 35 having a size different from that of the slot 3 includes two slots 35 a and 35 b that are orthogonal to each other at the center, and constitutes a part of the second polarization diversity antenna element 6.

  On the printed circuit board 40, two unillustrated power feeding microstrip lines are formed. Each of these two power supply microstrip lines is provided with a foil (thin film) made of a conductor material (for example, copper) on the back surface of the printed circuit board 40 made of a dielectric material on which the slot 3 and the slot 35 are formed. It is formed by removing a part of the conductor material by processing. Each of these two feeding microstrip lines is formed to be orthogonal to the slots 3 and 35.

  A plurality of the slots 3 are arranged along the longitudinal direction on the elongated printed circuit board 40, and the slots 35 are provided on both sides in the longitudinal direction of each slot 3 or between the longitudinal directions of each slot 3. FIG. 3 shows an embodiment in which the slots 35 are provided on both longitudinal sides of each slot 3.

  As shown in FIG. 1 and FIG. 2, the second printed circuit board 22 is formed by forming a dielectric material similar to the printed circuit board 40 into a plate shape, and is provided on the surface of the dielectric material with a conductive material (for example, copper). In this structure, the parasitic element 22a is formed by etching a thin foil (thin film). The parasitic element 22a is an element pattern formed on the printed circuit board 22 by leaving the conductor material in a cross shape so as to be orthogonal to each other at the center, and is arranged in parallel to the slot 3 provided on the printed circuit board 40. Patterned so that it can be.

  The spacer 28 is a member for fixing the second printed circuit board 22 on the printed circuit board 40 in parallel with the slot 3 and has, for example, a cylindrical or polygonal column shape.

  The spacer 28 may be provided at a position that does not affect the radiation and resonance of the electromagnetic wave using a member that does not affect the radiation and resonance of the electromagnetic wave of the first polarization diversity antenna element 2 to be formed.

  The parasitic element 22a is provided in parallel with the slot 3 so that the second printed board 22 covers the slot 3, and is formed in multiple stages in the vertical direction of the printed board 40 as necessary. The printed circuit board 40 and the second printed circuit board 22 are provided at regular intervals, and are held and fixed by a spacer 28.

  The parasitic element 22a re-radiates the electromagnetic wave radiated from the slot 3 and has a function of making the antenna directivity more favorable.

  The metal plate 51 is provided in the vicinity of each first polarization diversity antenna element 2, and is disposed so that each first polarization diversity antenna element 2 is placed on both sides of the printed board 40 in the width direction. The

  The metal plate 51 is formed of a metal plate having a size corresponding to the operating frequency of each first polarization diversity antenna element 2, and has, for example, a saddle shape formed by bending a single plate as shown in FIG. ing. As shown in FIG. 1, the metal plate 51 is attached so that one surface bent to the printed circuit board 40 is in close contact, and the other surface bent is perpendicular to the printed circuit board 40.

  When the polarized electromagnetic wave transmitted / received by the first polarization diversity antenna element 2 resonates between the slot 3 (see FIG. 3) and the parasitic element 22a, the metal plate 51 has a polarization angle of the electromagnetic wave. It has a function to adjust.

  The second polarization diversity antenna element 6 includes two slots 35 (shown in FIG. 3) that are orthogonal to each other at the center and have different sizes from the slots 3 formed on the printed board 40. Two second power supply microstrip lines (not shown) formed on the back side so as to be orthogonal to the respective slots 35 of the second size, and two or more third printed circuit boards parallel to the printed circuit board 40 A second parasitic element 32a formed of two conductor patterns provided in parallel with the slot 35 of the second size on the top 32 and perpendicular to the center, and the third printed circuit board 32 are connected to the printed circuit board 40. And a spacer 29 for fixing on the top.

  A structure in which a second metal plate 52 having a size corresponding to the second polarization diversity antenna element 6 is disposed on both sides in the width direction of the printed circuit board 40 of each second polarization diversity antenna element 6. It has become.

  The second polarization diversity antenna element 6 and the second metal plate 52 constitute a polarization antenna element for a high frequency.

  The third printed circuit board 32 is formed by using the same dielectric material as that of the printed circuit board 40 in the form of a plate, and etching is performed on a foil (thin film) provided on the surface of the dielectric material with a conductive material (for example, copper). Thus, the parasitic element 32a is formed. The parasitic element 32a is an element pattern formed on the printed circuit board 32 by leaving the conductor material in a cross shape so as to be orthogonal to each other at the center, and is arranged in parallel with the slot 35 provided on the printed circuit board 40. Patterned so that it can be.

  The spacer 29 is a member for fixing the third printed circuit board 32 on the printed circuit board 40 in parallel with the slot 35 and has, for example, a cylindrical or polygonal column shape.

  The parasitic elements 32 a are provided in parallel with the slots 35 so that the third printed circuit board 32 covers the slots 35, and are formed in multiple stages in the vertical direction of the printed circuit board 40 as necessary. The printed circuit board 40 and the third printed circuit board 22 are provided at regular intervals, and are held and fixed by a spacer 29.

  The parasitic element 32a re-radiates the electromagnetic wave radiated from the slot 35 and has a function of making the antenna directivity more favorable.

  The spacer 29 may be provided at a position that does not affect the radiation and resonance of the electromagnetic wave using a member that does not affect the radiation and resonance of the electromagnetic wave of the second polarization diversity antenna element 6 to be formed.

  The second metal plate 52 is provided opposite to the vicinity of each second polarization diversity antenna element 6 so that each second polarization diversity antenna element 6 is interposed between both sides of the printed board 40 in the width direction. Placed in.

  As shown in FIG. 5, the second metal plate 52 is formed by bending the metal plate to be attached to the printed circuit board 40 and the metal plate element 52 a having a size corresponding to the use frequency of each second polarization diversity antenna element 6. A mounting portion 52b formed by processing, and a spacer 61 for connecting the metal plate element 52a and the mounting portion 52b as a set of members are configured.

  As shown in FIG. 1, the second metal plate 52 is attached so that one surface of the attachment portion 52 b is in close contact with the printed circuit board 40. The second metal plate 52 adjusts the polarization angle of the electromagnetic wave when the electromagnetic wave transmitted and received by the polarization diversity antenna element 6 resonates between the slot 35 (see FIG. 3) and the parasitic element 32a. have.

  As shown in the drawing, the metal plate element 52a is bent along the longitudinal direction of the long and narrow plate and has a L-shaped cross section.

  The spacer 61 is made of an insulating material and has, for example, a columnar or polygonal column shape, and the metal plate element 52a and the attachment portion 52b are coupled and fixed.

  Next, the function and effect of the slot feeding antenna 1 will be described.

  First, the case where there are no metal plates 51 and 52 will be described.

  The slot-fed antenna 1 transmits / receives a desired low-frequency electromagnetic wave from a plurality of arranged first polarization diversity antenna elements 2 and transmits / receives a desired high-frequency electromagnetic wave from the second polarization diversity antenna element 6. It has a function to do.

  In the first polarization diversity antenna element 2, low-frequency electromagnetic waves are fed from each of the two feeding microstrip lines provided so as to be orthogonal to the slot 3, and the low-frequency electromagnetic waves are fed from the slot 3. Radiated.

  The oblique cross-shaped slots 3 formed in the printed circuit board 40 and orthogonal to each other at the center radiate electromagnetic waves having different polarizations from the slits 3a and 3b. For example, a + 45 ° polarized electromagnetic wave is emitted from the slot 3a, and a −45 ° polarized electromagnetic wave is emitted from the slot 3b.

  Some of the electromagnetic waves radiated from the slots 3a and 3b are radiated directly to the free space as they are, and some of the radiated electromagnetic waves are radiated to the parasitic element 22a. The electromagnetic wave radiated to the parasitic element 22a is reradiated toward the free space.

  At this time, resonance due to electromagnetic waves occurs between the slot 3 and the parasitic element 22a.

  The antenna directivity pattern of the first polarization diversity antenna element 2 is formed by combining the electromagnetic wave radiated from each slot 3 and the electromagnetic wave radiated from each parasitic element 22a.

  By combining the antenna directivity patterns of the first polarization diversity antenna elements 2 thus formed, the low-frequency antenna directivity pattern of the slot-fed antenna 1 is formed.

  The antenna directivity is directed vertically from the printed circuit board 40 toward the second printed circuit board 22. Due to the formed antenna directivity pattern, low-frequency electromagnetic waves are radiated in the direction of the antenna directivity.

  The slot-fed antenna 1 is an antenna having a polarization diversity function capable of transmitting and receiving + 45 ° polarization and −45 ° polarization due to low-frequency electromagnetic waves in the synthesized antenna directivity pattern.

  In the second polarization diversity antenna element 6, high frequency electromagnetic waves are fed from each of the two feeding microstrip lines provided so as to be orthogonal to the slots 35, and the high frequency electromagnetic waves are fed from the slots 35. Radiated.

  The oblique cross slots 35 formed in the printed circuit board 40 and orthogonal to each other at the center radiate electromagnetic waves having different polarizations from the respective slits 35a and 35b. For example, a + 45 ° polarized electromagnetic wave is emitted from the slot 35a, and a −45 ° polarized electromagnetic wave is emitted from the slot 35b.

  Some of the electromagnetic waves radiated from the slots 35a and 35b are radiated directly to the free space as they are, and some of the radiated electromagnetic waves are radiated to the parasitic element 32a. The electromagnetic wave radiated to the parasitic element 32a is reradiated toward the free space.

  At this time, resonance due to electromagnetic waves occurs between the slot 35 and the parasitic element 32a.

  The antenna directivity pattern of the second polarization diversity antenna element 6 is formed by combining the electromagnetic waves radiated from the slots 35 and the electromagnetic waves radiated from the parasitic elements 32a.

  The antenna directivity is directed vertically from the printed circuit board 40 toward the third printed circuit board 32. Due to the formed antenna directivity pattern, high-frequency electromagnetic waves are radiated in the direction of the antenna directivity.

  By combining the antenna directivity patterns of the formed second polarization diversity antenna elements 6, the high-frequency antenna directivity pattern of the slot-fed antenna 1 is formed.

  The slot-fed antenna 1 is an antenna having a polarization diversity function capable of transmitting and receiving + 45 ° polarization and −45 ° polarization due to high frequency electromagnetic waves in the synthesized antenna directivity pattern.

  As described above, the slot-fed antenna 1 has a low-frequency antenna directivity pattern due to the first polarization diversity antenna elements 2 without the metal plate 51.

  However, in this case, when viewed from each first polarization diversity antenna element 2, there is a first polarization diversity antenna element 2 adjacent in the vicinity in the antenna longitudinal direction except for both ends of the printed circuit board. Is a state in which the adjacent first polarization diversity antenna element 2 does not exist, and the symmetry of the antenna is broken. For this reason, there has been a problem that the cross polarization discrimination is deteriorated due to the influence of the adjacent first polarization diversity antenna elements 2.

  The metal plate 51 is a member provided to solve this problem. As shown in FIGS. 1 and 2, the metal plate 51 is provided to face each other across the first polarization diversity antenna element 2. Thus, resonance between the radiated electromagnetic wave from the slot 3 and the re-radiated electromagnetic wave from the parasitic element 22a is helped, and the symmetry of the printed board 40 in the width direction is improved. For this reason, the metal plate 51 exhibits a function of improving the cross polarization discrimination degree of the first polarization diversity antenna element 2.

  That is, by providing the metal plate 51 in the width direction of the printed circuit board 40, the pseudo polarization diversity antenna element 2 is produced in a pseudo manner in the width direction of the printed board 40, and the cross polarization identification is performed. The degree of improvement improves the polarization diversity function of the slot-fed antenna 1 at a low frequency.

  Also in the second polarization diversity antenna element 6, by providing the second metal plate 52, the same effect can be obtained by transmitting and receiving electromagnetic waves of high frequency.

  That is, by providing the second metal plate 52 in the width direction of the printed circuit board 40, the polarization diversity antenna element 6 is simulated in the width direction of the printed circuit board 40. By improving the degree, the polarization diversity function of the slot-fed antenna 1 at a high frequency is improved.

  The shapes of the metal plate 51 processed and bent for the low frequency band and the second metal plate 52 for the high frequency band are not limited to the shapes and bent structures shown in FIGS. Any metal plate can be used as long as it is a metal plate that helps the resonance between the slot 3 and the parasitic element 22a or the resonance between the slot 35 and the parasitic element 32a and improves the cross polarization discrimination.

  For example, the shape of the metal plate element 54 as shown in FIG. 6A or the shape of the metal plate element 55 as shown in FIG. 6B may be used instead of the metal plate element 52a.

  The metal plate elements 54 and 55 are processed so that one or more cuts are made on one side of the bent L-shaped metal plate element 52a. Depending on the number of cuts, the shape and size of the cuts, there is no power supply The resonance state with the element 32a can be adjusted, and the cross polarization discrimination can be improved.

  In this embodiment, the case of transmission / reception of two frequencies is described for the sake of simplicity, but transmission / reception of three or more frequencies is performed by further providing a third and subsequent polarization diversity antenna elements and a metal plate. In this case, the same effect of improving the cross polarization discrimination can be obtained.

  The present invention is not limited to a polarization antenna, and can be applied to an antenna configured by arranging a plurality of antenna elements when the electrical performance of the antenna deteriorates due to the symmetry of the arrangement.

It is a structural diagram showing a slot feeding type antenna which is an embodiment. It is a front view which shows the slot feeding type antenna which is embodiment. It is a front view which shows the antenna element board | substrate of a slot feeding type antenna. It is a general-view figure which shows the metal plate processed and bent for low frequencies. It is a general-view figure which shows the 2nd metal plate formed for high frequencies. Fig.6 (a) is a general-view figure which shows the metal element bent into the L shape, and having made several cut | notch. FIG. 6B is a schematic view showing a metal element that is bent into an L shape and has one cut.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Slot feeding type antenna 2 1st polarization diversity antenna element 6 2nd polarization diversity antenna element 22 2nd printed circuit board 22a Parasitic element 28, 29 Spacer 32 3rd printed circuit board 32a Parasitic element 40 Printed circuit board 51 Metal plate 52 Second metal plate

Claims (9)

  A plurality of antenna elements are arranged along a longitudinal direction on an elongated printed circuit board, and a metal plate is disposed on both sides of the width direction of the printed circuit board of each antenna element so as to face each other with the antenna elements sandwiched therebetween. Slot feed antenna.   2. The slot feeding antenna according to claim 1, wherein each of the antenna elements is a polarization diversity antenna element.   The polarization diversity antenna element is used as a first polarization diversity antenna element, and a second polarization is provided between both longitudinal sides of the first polarization diversity antenna element or between the longitudinal directions of the first polarization diversity antenna element. 3. The slot feeding type according to claim 2, wherein a plurality of diversity antenna elements are arranged in the longitudinal direction of the printed circuit board, and second metal plates are arranged on both sides of the printed circuit board in the width direction of each of the second polarization diversity antenna elements. antenna.   The first polarization diversity antenna element includes two slots formed on the printed board and orthogonal to each other at the center, and two slots formed on the back side of the printed board so as to be orthogonal to the slots. And a parasitic element formed of two conductor patterns orthogonal to each other provided in parallel with the slot on two or more second printed boards parallel to the printed board. A slot-fed antenna according to claim 3.   The second polarization diversity antenna element includes two second size slots formed on the printed board and orthogonal to each other at the center, and the second size on the back side of the printed board. Two second power-feeding microstrip lines formed so as to be orthogonal to the second slot, and parallel to the second size slot on two or more third printed boards parallel to the printed board 4. A slot fed antenna according to claim 3, further comprising a second parasitic element formed by two conductor patterns orthogonal to each other provided at the center.   The metal plate is bent to have a size corresponding to the polarization diversity antenna element, and the second metal plate is bent to have a size corresponding to the second polarization diversity antenna element. The slot feeding type antenna according to claim 1 or 3, wherein:   The second metal plate includes a metal plate element formed by bending, a mounting portion formed by bending and fixed to a printed circuit board, and a spacer for coupling and fixing the metal element and the mounting portion. 7. A slot feeding antenna according to claim 3 or 6, wherein the slot feeding antenna is configured.   8. The slot feeding antenna according to claim 7, wherein the metal plate element is bent along the longitudinal direction of an elongated plate and is formed in an L shape. 9. The slot feeding antenna according to claim 8, wherein the metal plate element has one or more cuts on one side of the L shape.

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