JP2014007537A - Antenna device of wireless base station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna device of a wireless base station the coverage of which can be expanded without having an adverse effect on the conventional coverage.SOLUTION: The antenna device of a wireless base station includes a first reflector which reflects radio waves emitted from an antenna element or reflects radio waves toward an antenna element, and a second reflector which reflects a side lobe due to the radio waves emitted from an antenna element and the radio waves reflected on the first reflector, or reflects the radio waves toward an antenna element and the first reflector.

Description

  The present invention relates to an antenna device for a radio base station.

  Conventionally known antenna devices for mobile phone radio base stations include an antenna element and a reflector (for example, Patent Document 1). If the antenna element is a transmission antenna element, the reflector reflects the back lobe generated by the transmission antenna element. If the antenna element is a receiving antenna element, the reflector reflects the radio wave toward the receiving antenna element.

JP 2003-8332 A

  However, since the antenna element has directivity, it restricts the coverage of the radio base station. If the antenna element is a transmission antenna element, the reception level at the user terminal (mobile station) in the null beam direction is low. If the antenna element is a reception antenna element, the reception level at the radio base station of radio waves from a user terminal in a direction where the sensitivity of the reception antenna element is low is low.

  Therefore, the present invention provides an antenna apparatus for a radio base station that can expand the coverage without adversely affecting the conventional coverage.

  An antenna device of a radio base station according to a first aspect of the present invention includes an antenna element that emits radio waves in response to an electrical signal, a first reflector that reflects radio waves emitted from the antenna elements, and the antenna A radio wave emitted from the element and a second reflector that reflects side lobes caused by the radio wave reflected by the first reflector. Since the second reflecting plate reflects the side lobe, the user terminal that does not reach the main lobe caused by the radio wave emitted from the antenna element and the radio wave reflected by the first reflecting plate receives the radio wave of the reflected side lobe. The coverage of the radio base station is expanded. Since the second reflecting plate reflects the side lobe, the coverage formed by the main lobe caused by the radio wave emitted from the antenna element and the radio wave reflected by the first reflecting plate is not affected.

  The main lobe caused by the radio wave emitted from the antenna element and the radio wave reflected by the first reflector is obliquely downward, and the second reflector reflects the side lobe obliquely upward. It is preferable. Usually, the antenna element of a radio base station is designed so that the main lobe is inclined downward in order to suppress interference with user terminals in cells of other radio base stations. For this reason, the main lobe may not reach the user terminal at the top of a high building in the cell of the radio base station. The second reflecting plate reflects the side lobe obliquely upward, so that the user terminal at the upper part of the tall building can receive the reflected side lobe radio wave.

  The antenna device according to the first aspect may include a plurality of the second reflecting plates. The presence of the plurality of second reflecting plates can further expand the coverage of the radio base station.

  The main lobe caused by the radio wave emitted from the antenna element and the radio wave reflected by the first reflector is obliquely downward, and the antenna device of the first aspect includes a plurality of the second reflectors. Any one of the plurality of second reflecting plates reflects the side lobe obliquely upward, and another one of the plurality of the second reflecting plates obliquely moves downward. May be reflected. Any of the second reflectors reflects the side lobes obliquely upward, so that the user terminal at the top of the tall building can receive the reflected side lobe radio waves. When the second reflector reflects the side lobe obliquely downward, the range of cells that the downlink radio wave reaches from the radio base station can be expanded.

  An antenna device of a radio base station according to a second aspect of the present invention includes an antenna element that generates an electrical signal corresponding to a received radio wave, a first reflector that reflects the radio wave toward the antenna element, An antenna element and a second reflector that reflects radio waves toward the first reflector. Since the second reflecting plate reflects radio waves toward the antenna element and the first reflecting plate, the coverage of the radio base station can be expanded as compared with the case where there is no second reflecting plate. The second reflector does not affect the radio wave that can be received by the antenna element in the absence of this, and therefore does not affect the conventional coverage.

  The antenna element and the first reflector are adjusted so that the antenna element has a large sensitivity to radio waves coming from diagonally downward, and the second reflector is radio waves coming from diagonally upward Is preferably reflected toward the antenna element and the first reflecting plate. Usually, the antenna element of a radio base station is designed so that the direction with high reception sensitivity is inclined downward in order to suppress interference received from user terminals in cells of other radio base stations. For this reason, the radio wave from the user terminal in the upper part of the high building in the cell of the radio base station may not reach the radio base station. The antenna element can receive the radio wave from the user terminal located in the upper part of the high building by reflecting the radio wave coming from the diagonally upward direction toward the antenna element and the first reflector. .

  The antenna device of the second aspect may also include a plurality of the second reflecting plates. The presence of the plurality of second reflecting plates can further expand the coverage of the radio base station.

  The antenna element and the first reflector are adjusted so that the antenna element has a large sensitivity to radio waves coming from diagonally below, and the antenna device of the second aspect includes a plurality of the second elements A plurality of the second reflectors includes a reflector, and any one of the plurality of second reflectors reflects a radio wave arriving from an obliquely upward direction toward the antenna element and the first reflector. Any of the other may reflect a radio wave coming from an obliquely downward direction toward the antenna element and the first reflecting plate. The antenna element receives the radio wave from the user terminal located in the upper part of the high building by reflecting the radio wave arriving from one of the second reflectors obliquely upward toward the antenna element and the first reflector. Any other second reflecting plate reflects an incoming radio wave from an obliquely downward direction toward the antenna element and the first reflecting plate, thereby transmitting an uplink radio wave to the radio base station. The range of cells that can be expanded.

  The surface of the second reflecting plate on the antenna element side is preferably curved in a convex shape. Thereby, the coverage of the radio base station can be further expanded. If the antenna element is a transmitting antenna element, the reflected radio wave is delivered to a wide range of directions by the surface of the second antenna element that is curved in a convex shape. If the antenna element is a receiving antenna element, radio waves coming from a wide range of directions are reflected toward the antenna element.

It is a perspective view which shows the antenna apparatus of the wireless base station which concerns on the 1st Embodiment of this invention. It is sectional drawing of the antenna apparatus of the wireless base station which concerns on 1st Embodiment. It is a figure which shows the use condition of the antenna apparatus of the wireless base station which concerns on 1st Embodiment. It is a figure which shows the other use condition of the antenna apparatus of the wireless base station which concerns on 1st Embodiment. It is a figure which shows the use condition of the antenna apparatus of the wireless base station which concerns on the 2nd Embodiment of this invention. It is a figure which shows the other use condition of the antenna apparatus of the wireless base station which concerns on 2nd Embodiment. It is a figure which shows the other use condition of the antenna apparatus of the wireless base station which concerns on 2nd Embodiment. It is a perspective view which shows the antenna apparatus of the wireless base station which concerns on the 3rd Embodiment of this invention. It is sectional drawing of the antenna apparatus of the wireless base station which concerns on 3rd Embodiment. It is a perspective view which shows the antenna apparatus of the wireless base station which concerns on the 4th Embodiment of this invention. It is sectional drawing of the antenna apparatus of the wireless base station which concerns on 4th Embodiment. It is a perspective view which shows the antenna apparatus of the wireless base station which concerns on the 5th Embodiment of this invention. It is sectional drawing of the antenna apparatus of the wireless base station which concerns on 5th Embodiment. It is a perspective view which shows the antenna apparatus of the wireless base station which concerns on the 6th Embodiment of this invention. It is sectional drawing of the antenna apparatus of the wireless base station which concerns on 6th Embodiment.

  Hereinafter, various embodiments according to the present invention will be described with reference to the accompanying drawings. The antenna device of the following embodiment is an antenna device of a mobile phone radio base station, but may be used in other communication systems such as Wi-Fi and WiMAX radio base stations.

First embodiment

  As shown in FIGS. 1 and 2, the antenna apparatus 10 of the radio base station according to the first embodiment of the present invention includes a radome 12, a plurality of antenna elements 16, a first reflector 14, and a second reflector. A reflector 18 is provided. The antenna element 16 is a known antenna element, and may be a transmission antenna element that emits radio waves according to an electric signal, or a reception antenna element that generates an electric signal according to received radio waves. Further, it may be a transmission / reception antenna element having a function of a transmission antenna element and a function of a reception antenna element. The number of antenna elements 16 is not limited to the illustrated embodiment, and may be 1 or 2, or 4 or more.

  The first reflecting plate 14 is disposed at a position away from the antenna element 16. When the antenna element 16 is a transmission antenna element, the first reflector 14 reflects the back lobe of the radio wave emitted from the antenna element 16 forward. When the antenna element 16 is a receiving antenna element, the first reflector 14 reflects radio waves toward the antenna element 16. The first reflector 14 is made of a material having good radio wave reflection characteristics. In this embodiment, the first reflecting plate 14 is generally a rectangular flat plate, but has a shape in which both end edges are bent.

  The radome 12 surrounds the first reflector 14 and the antenna element 16 in order to protect the first reflector 14 and the antenna element 16. The radome 12 is made of a material that transmits radio waves, such as resin.

  The second reflector 18 is disposed outside the radome 12. When the antenna element 16 is a transmitting antenna element, the second reflector 18 reflects side lobes caused by the radio wave emitted from the antenna element 16 and the radio wave reflected by the first reflector 14. When the antenna element 16 is a receiving antenna element, the second reflector 18 reflects radio waves toward the antenna element 16 and the first reflector 14. The second reflector 18 is made of a material having good radio wave reflection characteristics. In this embodiment, the second reflecting plate 18 is a flat plate. The angle of the second reflector 18 with respect to the vertical axis can be adjusted, and the angle of the second reflector 18 with respect to the vertical axis can be adjusted.

  An example of use of the antenna device 10 will be described with reference to FIGS. 3 and 4. Assume that the antenna element 16 is a transmitting antenna element. 3 and 4, the main lobe ML caused by the radio wave emitted by the antenna element 16 and the radio wave reflected by the first reflecting plate 14, the radio wave emitted by the antenna element 16, and the first reflecting plate 14. A side lobe SL caused by the radio wave reflected by is shown. The second reflector 18 reflects one of the side lobes SL. Since the second reflector 18 reflects the side lobe SL, the user terminal to which the main lobe ML caused by the radio wave emitted from the antenna element 16 and the radio wave reflected by the first reflector 14 does not reach the second lobe. The radio wave of the side lobe SL reflected by the reflector 18 can be received, and as a result, the coverage of the radio base station is expanded. Since the second reflector 18 reflects the side lobe SL, the coverage formed by the main lobe ML caused by the radio wave emitted from the antenna element 16 and the radio wave reflected by the first reflector 14 is affected. Don't give.

  In FIG. 3, the main lobe ML caused by the radio wave emitted from the antenna element 16 and the radio wave reflected by the first reflector 14 is obliquely downward. Usually, the antenna element 16 of the radio base station is designed such that the main lobe ML is inclined downward in order to suppress interference with user terminals in cells of other radio base stations. For this reason, the main lobe ML may not reach the user terminal on the upper part of the tall building 30 in the cell 20 of the radio base station (for example, the floor 31 in FIG. 3). In addition, no side lobe is directed to the position, and radio waves do not reach the user terminal there, or the reception level of radio waves may be weak.

  In FIG. 3, the second reflecting plate 18 is installed so as to reflect the side lobe SL obliquely upward. When the second reflector 18 reflects the side lobe obliquely upward, the user terminal on the upper portion of the tall building 30 (for example, the floor 31 in FIG. 3) receives the radio waves of the reflected side lobe SL. Can do. Therefore, for example, when a high building is newly built in the cell of the radio base station, the second reflector 18 is provided to adversely affect the existing cell 20 without the second reflector 18. It is possible to provide a communication service to user terminals in a building without giving

  In FIG. 4, the second reflecting plate 18 is installed so as to reflect the side lobes SL obliquely downward. In this case, the expansion of the communication service to the user terminal in a high building cannot be expected. However, the cell range can be expanded as indicated by reference numeral 21 without adversely affecting the existing cell 20 in the absence of the second reflector 18.

  Similar effects are achieved when the antenna element 16 is a receiving antenna element. In this case, since the second reflector 18 reflects radio waves toward the antenna element 16 and the first reflector 14, the coverage of the radio base station is expanded as compared with the case where the second reflector 18 is not provided. be able to. The second reflector 18 does not affect the radio wave that can be received by the antenna element 16 in the absence of this, and therefore does not affect the conventional coverage.

  When the antenna element 16 is a receiving antenna element, the antenna element 16 and the first reflecting plate 14 are adjusted so that the antenna element 16 has a large sensitivity with respect to radio waves coming from diagonally below. Usually, the antenna element 16 of a radio base station is designed so that the direction with high reception sensitivity is obliquely downward in order to suppress interference received from user terminals in cells of other radio base stations. For this reason, the radio wave from the user terminal in the upper part of the high building 30 in the cell 20 of the radio base station (for example, the floor 31 in FIG. 3) does not reach the radio base station, or the radio wave reception level at the radio base station is May be weak.

  In FIG. 3, the second reflector 18 reflects radio waves coming from diagonally upward toward the antenna element 16 and the first reflector 14. The antenna element 16 receives the radio wave from the user terminal located in the upper part of the high building by reflecting the radio wave arriving from the diagonally upward direction toward the antenna element 16 and the first reflector 14. can do. Therefore, for example, when a high building is newly built in the cell of the radio base station, the second reflector 18 is provided to adversely affect the existing cell 20 without the second reflector 18. It is possible to provide a communication service to user terminals in a building without giving

  In FIG. 4, the second reflector 18 is installed so as to reflect radio waves coming from diagonally downward toward the antenna element 16 and the first reflector 14. In this case, the expansion of the communication service to the user terminal in a high building cannot be expected. However, the cell range can be expanded as indicated by reference numeral 21 without adversely affecting the existing cell 20 in the absence of the second reflector 18.

Second Embodiment As shown in FIG. 5, an antenna device 100 of a radio base station according to a second embodiment of the present invention is already added to the configuration of the antenna device 10 of the first embodiment. One second reflector 19 is provided. That is, the antenna device 100 includes a plurality of second reflecting plates 18 and 19.

  The second reflector 19 is disposed outside the radome 12. When the antenna element 16 is a transmission antenna element, the second reflector 19 reflects the side lobe SL caused by the radio wave emitted from the antenna element 16 and the radio wave reflected by the first reflector 14. When the antenna element 16 is a receiving antenna element, the second reflector 19 reflects radio waves toward the antenna element 16 and the first reflector 14. The second reflector 19 is made of a material having good radio wave reflection characteristics. In this embodiment, the second reflecting plate 19 is a flat plate. The angle of the second reflector 19 can be adjusted with respect to the vertical axis, and the angle of the second reflector 19 can be adjusted around the vertical axis.

  By providing the plurality of second reflectors 18 and 19, the coverage of the radio base station can be further expanded. An example of use of the antenna device 100 will be described with reference to FIGS. 5, 6, and 7. The same reference numerals are used in FIG. 5, FIG. 6, and FIG. 7 to show the components common to the first embodiment.

  Assume that the antenna element 16 is a transmitting antenna element. The second reflector 18 reflects one of the side lobes SL. The second reflector 19 reflects the other one of the side lobes SL. Since the second reflectors 18 and 19 reflect the side lobe SL, the user terminal to which the main lobe ML caused by the radio wave emitted from the antenna element 16 and the radio wave reflected by the first reflector 14 does not reach is the first user terminal. The radio waves of the side lobes SL reflected by the two reflectors 18 and 19 can be received. As a result, the coverage of the radio base station is expanded. Since the second reflectors 18 and 19 reflect the side lobe SL, the coverage formed by the main lobe ML caused by the radio wave emitted from the antenna element 16 and the radio wave reflected by the first reflector 14 is not included. Does not affect.

  In FIG. 5, the main lobe ML caused by the radio wave emitted from the antenna element 16 and the radio wave reflected by the first reflector 14 is obliquely downward. Usually, the antenna element 16 of the radio base station is designed such that the main lobe ML is inclined downward in order to suppress interference with user terminals in cells of other radio base stations. For this reason, the main lobe ML may not reach the user terminals on the upper part of the high building 30 (for example, the floors 31 and 32 in FIG. 5) in the cell 20 of the radio base station. In addition, no side lobe is directed to the position, and radio waves do not reach the user terminal there, or the reception level of radio waves may be weak.

  In FIG. 5, the second reflector 18 is installed so as to reflect the side lobe SL obliquely upward, and the second reflector 19 also reflects the side lobe SL obliquely upward. is set up. When the second reflector 18 reflects the side lobe obliquely upward, the user terminal on the upper portion of the tall building 30 (for example, the floor 31 in FIG. 5) receives the radio wave of the reflected side lobe SL. Can do. When the second reflector 19 reflects the side lobe obliquely upward, the user terminal on the upper portion of the tall building 30 (for example, the floor 32 in FIG. 5) receives the radio waves of the reflected side lobe SL. Can do. As described above, the plurality of second reflecting plates 18 and 19 are installed so that the radio waves reach different locations. For example, when a high building is newly constructed in a cell of a radio base station, the existing cell 20 without the second reflectors 18 and 19 is provided by providing the second reflectors 18 and 19. It is possible to provide a communication service to user terminals in the building without adversely affecting the user terminal. In particular, since the second reflectors 18 and 19 deliver radio waves toward different positions, the coverage of the radio base station can be significantly increased.

  In FIG. 6, the second reflectors 18 and 19 are installed so as to reflect the side lobes SL obliquely downward. In this case, the expansion of the communication service to the user terminal in a high building cannot be expected. However, the cell range can be expanded as indicated by reference numerals 21 and 22 without adversely affecting the existing cells 20 in the absence of the second reflectors 18 and 19. In particular, since the second reflectors 18 and 19 deliver radio waves toward different positions, the coverage of the radio base station can be significantly increased.

  In FIG. 7, one second reflecting plate 19 is installed so as to reflect the side lobe SL obliquely upward, and the other second reflecting plate 18 causes the side lobe SL to face obliquely upward. It is installed to reflect. When the second reflector 19 reflects the side lobe obliquely upward, the user terminal on the upper portion of the tall building 30 (for example, the floor 31 in FIG. 7) receives the radio waves of the reflected side lobe SL. Can do. Further, the other second reflector 18 reflects the side lobes SL obliquely downward, so that the existing cell 20 is not adversely affected. It is possible to extend the range of cells that radio waves reach.

  Similar effects are achieved when the antenna element 16 is a receiving antenna element. In this case, since the second reflectors 18 and 19 reflect radio waves toward the antenna element 16 and the first reflector 14, compared with the case where the second reflectors 18 and 19 are not provided, Coverage can be expanded. Since the second reflectors 18 and 19 do not affect the radio waves that can be received by the antenna element 16 in the absence of this, the conventional reflectors do not affect the coverage.

  When the antenna element 16 is a receiving antenna element, the antenna element 16 and the first reflecting plate 14 are adjusted so that the antenna element 16 has a large sensitivity with respect to radio waves coming from diagonally below. Usually, the antenna element 16 of a radio base station is designed so that the direction with high reception sensitivity is obliquely downward in order to suppress interference received from user terminals in cells of other radio base stations. For this reason, the radio wave from the user terminal on the upper part of the high building 30 in the cell 20 of the radio base station (for example, the floors 31 and 32 in FIG. 5) does not reach the radio base station or the radio base station receives the radio wave. The level may be weak.

  In FIG. 5, the second reflector 18 reflects radio waves arriving from an obliquely upward direction (for example, the floor 31 of the building 30) toward the antenna element 16 and the first reflector 14. The second reflector 19 also reflects radio waves coming from an obliquely upward direction (for example, the floor 32 of the building 30) toward the antenna element 16 and the first reflector 14. The second reflecting plates 18 and 19 reflect the radio waves coming from diagonally upward toward the antenna element 16 and the first reflecting plate 14, so that the radio waves from the user terminal on the upper part of the high building are reflected by the antenna element 16. Can be received. Therefore, for example, when a high building is newly constructed in the cell of the radio base station, by providing the second reflectors 18 and 19, the existing ones without the second reflectors 18 and 19 are provided. A communication service can be provided to user terminals in the building without adversely affecting the cell 20. In particular, since the second reflectors 18 and 19 deliver radio waves from separate positions to the antenna element 16 and the first reflector 14, the coverage of the radio base station can be significantly increased.

  In FIG. 6, the second reflectors 18 and 19 are installed so as to reflect radio waves coming from diagonally downward toward the antenna element 16 and the first reflector 14. In this case, the expansion of the communication service to the user terminal in a high building cannot be expected. However, the cell range can be expanded as indicated by reference numerals 21 and 22 without adversely affecting the existing cells 20 in the absence of the second reflectors 18 and 19. In particular, since the second reflectors 18 and 19 deliver radio waves from separate positions to the antenna element 16 and the first reflector 14, the coverage of the radio base station can be significantly increased.

  In FIG. 7, one second reflecting plate 19 is installed so as to reflect radio waves coming from diagonally upward toward the antenna element 16 and the first reflecting plate 14, and the other second reflecting plate 19. The plate 19 is installed so as to reflect radio waves coming from diagonally downward toward the antenna element 16 and the first reflecting plate 18. The second reflector 19 reflects a radio wave arriving from an obliquely upward direction (for example, the floor 31 of the building 30) toward the antenna element 15 and the first reflector 14, thereby allowing the user terminal located above the tall building to Can be received by the antenna element. The other second reflector 18 reflects the radio wave arriving from diagonally downward toward the antenna element 16 and the first reflector 14, thereby preventing the existing cell 20 from being adversely affected, and denoted by reference numeral 21. Thus, the range of cells that can transmit uplink radio waves to the radio base station can be expanded.

  5, 6, and 7 show two second reflectors 18 and 19, three or more second reflectors may be provided. In addition, a plurality of second reflectors adapted to user terminals at high positions and a plurality of second reflectors for extending the cell range may be provided.

Third Embodiment In the first embodiment and the second embodiment, the second reflectors 18 and 19 are flat plates, but the surface on the antenna element 16 side is curved in a convex shape. A reflector may be used. The antenna device according to the third embodiment includes such a second reflector.

  As shown in FIGS. 8 and 9, the antenna device 110 according to the third embodiment includes a second reflector 118 that is a curved plate instead of the second reflector 18 that is a flat plate. In order to show the components common to the first embodiment, the same reference numerals are used in FIG. 8 and FIG. 9, and these will not be described in detail. The second reflecting plate 118 is used for the same application as the second reflecting plate 18 of the first embodiment.

  The second reflector 118 is formed of a material having good radio wave reflection characteristics. The surface of the second reflector 118 on the antenna element 16 side is curved in a convex shape. Therefore, the coverage of the radio base station can be further expanded. Specifically, if the antenna element 16 is the transmission antenna element 16, the reflected radio wave is delivered to a wide range of directions by the convexly curved surface of the second antenna element 16 on the antenna element 16 side. FIG. 8 shows how the radio waves reflected by the second reflector 118 travel in a wide range of directions. If the antenna element 16 is the receiving antenna element 16, radio waves that have arrived from a wide range of directions are reflected toward the antenna element 16.

  As a combination of the second embodiment and the third embodiment, a plurality of second reflecting plates whose surfaces on the antenna element 16 side are curved in a convex shape may be provided.

Fourth Embodiment The fourth embodiment relates to the deformation of the first reflector. As shown in FIG. 10 and FIG. 11, the antenna device 120 of the radio base station according to the fourth embodiment has a first reflector 124 instead of the first reflector 14 of the first embodiment. Is provided. In order to show the components common to the first embodiment, the same reference numerals are used in FIG. 10 and FIG. 11, and these will not be described in detail. The first reflector 124 is used for the same application as the first reflector 14 of the first embodiment. The first reflector 124 is made of a material having good radio wave reflection characteristics. The first reflector 124 has two flat plate portions 124A and 124B that are rectangular and extend in the same direction as the direction in which the antenna element 16 extends. One end of the flat plate portion 124B is connected to one end of the flat plate portion 124A, and the flat plate portions 124A and 124B are perpendicular to each other. Such a first reflector 124 may be used in the second embodiment and the third embodiment.

Fifth Embodiment The fifth embodiment relates to deformation of the first reflector. As shown in FIGS. 12 and 13, the antenna device 130 of the radio base station according to the fifth embodiment includes a first reflector 134 instead of the first reflector 14 of the first embodiment. Is provided. In order to show the components common to the first embodiment, the same reference numerals are used in FIG. 12 and FIG. 13, and these will not be described in detail. The 1st reflecting plate 134 is used for the same use as the 1st reflecting plate 14 of 1st Embodiment. The first reflector 134 is made of a material having good radio wave reflection characteristics. The first reflecting plate 134 is a rectangular flat plate. Such a first reflector 134 may be used in the second embodiment and the third embodiment.

Sixth Embodiment The sixth embodiment relates to deformation of the first reflector. As shown in FIGS. 14 and 15, the antenna apparatus 140 of the radio base station according to the sixth embodiment has a first reflector 144 instead of the first reflector 14 of the first embodiment. Is provided. In order to show the components common to the first embodiment, the same reference numerals are used in FIG. 14 and FIG. 15, and these will not be described in detail. The 1st reflecting plate 144 is used for the same use as the 1st reflecting plate 14 of 1st Embodiment. The first reflector 144 is made of a material having good radio wave reflection characteristics. The first reflecting plate 144 is a rectangular curved plate, and the surface on the antenna element 16 side is concave. Such a first reflector 144 may be used in the second embodiment and the third embodiment.

Other Modifications At least one of the first reflecting plate and the second reflecting plate may be formed of a metamaterial disclosed in Japanese Unexamined Patent Application Publication No. 2009-153095.

10, 100, 110, 120, 130, 140 Antenna device 12 Radome 16 Antenna element 14, 124, 134, 144 First reflector 18, 19, 118 Second reflector

Claims (9)

An antenna element that emits radio waves in response to an electrical signal;
A first reflector that reflects radio waves emitted from the antenna element;
An antenna apparatus for a radio base station, comprising: a radio wave emitted from the antenna element; and a second reflector that reflects a side lobe caused by the radio wave reflected by the first reflector. The main lobe caused by the radio wave emitted from the antenna element and the radio wave reflected by the first reflector is obliquely downward,
2. The radio base station antenna apparatus according to claim 1, wherein the second reflecting plate reflects the side lobe obliquely upward. 3.   The radio base station antenna device according to claim 1, further comprising a plurality of the second reflecting plates. A plurality of the second reflectors;
One of the plurality of second reflecting plates reflects the side lobe obliquely upward, and the other of the plurality of the second reflecting plates reflects the side lobe obliquely downward. The radio base station antenna apparatus according to claim 2, wherein: An antenna element that generates an electrical signal corresponding to the received radio wave;
A first reflector that reflects radio waves toward the antenna element;
An antenna device for a radio base station, comprising: the antenna element; and a second reflector that reflects radio waves toward the first reflector. The antenna element and the first reflector are adjusted so that the antenna element has a high sensitivity to radio waves coming from diagonally below,
6. The antenna apparatus for a radio base station according to claim 5, wherein the second reflecting plate reflects radio waves coming from diagonally upward toward the antenna element and the first reflecting plate.   The antenna device for a radio base station according to claim 5, further comprising a plurality of the second reflecting plates. A plurality of the second reflectors;
Any of the plurality of second reflecting plates reflects radio waves coming from diagonally upward toward the antenna element and the first reflecting plate, and any one of the plurality of second reflecting plates. 7. The radio base station antenna apparatus according to claim 6, wherein radio waves arriving from an obliquely downward direction are reflected toward the antenna element and the first reflector.   The antenna device for a radio base station according to any one of claims 1 to 8, wherein a surface of the second reflector on the antenna element side is curved in a convex shape.

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