JP2009267502A - Antenna unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna unit for which wiring investigation is not needed, and work efficiency is improved without adversely affecting antenna characteristics, and whose mass production cost can be reduced. <P>SOLUTION: The antenna unit includes: a grounded conductor 2; a radiation element 3 arranged on one surface of the grounded conductor 2; control equipment 4 arranged on the other surface of the grounded conductor 2 so as to control the radiation element 3; a radome 5 arranged to cover the grounded conductor 2, the radiation element 3, and the control equipment 4; a lightning rod 6 arranged in the upper part of the radome 5; and a grounded terminal base 7 for allowing an electric current to escape to the ground through the lightning rod 6 in the case of the falling of a thunderbolt. In the antenna device, one end of the grounded conductor 2 is electrically connected to the lightning rod 6, and also the other end of the grounded conductor 2 is electrically connected to the grounded terminal base 7. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an antenna device for a cellular phone base station having a lightning arrester.

  FIG. 4 shows a cellular phone base station antenna having a conventional lightning protection device. In the mobile phone base station antenna 41, lightning protection measures are achieved by electrically connecting a lightning rod 42 at the top of the antenna and a ground terminal seat 43 at the bottom of the antenna by a ground wire 44 such as a stranded wire installed inside the antenna. Is realized.

  In the antenna for a mobile phone base station, lightning protection measures are required when installing the antenna for a mobile phone base station under a specific situation, for example, when there is no lightning rod in a building or a steel pipe column for mounting an antenna. This lightning protection measure has an important role in protecting the building under the antenna and the radio connected to the antenna.

  As shown in FIG. 4, the mobile phone base station antenna 41 is covered with a radome 45. In FIG. 4, for simplification of illustration, the wiring of the ground wire 44 is a single wire.

  The control device 47 includes a device such as a phase shifter that changes the beam direction of radio waves and a wiring cable for electrically connecting these devices and the antenna radiating element 46 to each other. Since there are dozens of wiring cables in the control device 47, the illustration is omitted in FIG.

  The prior art document information related to the invention of this application includes the following.

Japanese Patent Laid-Open No. 10-126125 JP 2006-209984 A

  However, since the antenna has a structure in which a large number of antenna radiating elements 46 that radiate radio waves and a control device 47 for controlling the antenna radiating elements 46 are arranged, and the space is limited, wiring of the ground wire 44 is easy. is not.

  In addition, in the mobile phone base station antenna 41 having a lightning protection device, it is necessary to wire the ground wire 44 in an empty space inside the antenna. However, the ground wire 44 should be wired from the antenna radiation element 46 to the radio wave radiation direction side. I can't. This is because the antenna radiating element 46 has a complicated structure in order to realize various characteristics such as desired radiation directivity, and the characteristics may be destroyed due to very few factors. For this reason, it is necessary to examine the wiring of the ground wire 44 in a limited space on the back surface of the chassis 48 that is opposite to the radio wave radiation direction so as not to affect the antenna characteristics. .

Furthermore, according to JIS standard A4201, the required cross-sectional area of the copper ground wire 44 is determined to be 16 mm ² or more. However, as described above, the ground that greatly exceeds the required cross-sectional area due to space and wiring complexity problems. Because the installation of the line 44 is difficult, the safety factor remains at the lowest acceptable level.

  Further, since the wiring of the ground wire 44 is a wiring that follows a complicated route, work efficiency is deteriorated and mass productivity is also deteriorated.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an antenna device that solves the above-described problems, improves work efficiency without affecting the characteristics of the antenna, and enables safer design.

  The present invention has been developed to achieve the above object, and includes a ground conductor, a radiating element installed on one surface of the ground conductor, and the radiating element installed on the other surface side of the ground conductor. A control device that controls the earth conductor, a radome provided so as to cover the ground conductor, the radiating element, and the control device, a lightning rod provided on the top of the radome, and a current from the lightning rod during a lightning strike to ground. In the antenna device provided with a ground terminal seat for connecting, the one end of the ground conductor and the lightning rod are electrically connected, and the other end of the ground conductor and the ground terminal seat are electrically connected. It is an antenna device.

  The present invention is an antenna device in which the ground conductor and the ground terminal seat are electrically connected via a metal plate formed separately from the ground conductor.

The present invention is the antenna device, wherein the ground conductor is a chassis made of aluminum having a cross-sectional area of 25 mm ² or more.

  According to the present invention, since the ground conductor is also used as a ground wire, it is not necessary to consider wiring, and the work efficiency can be improved and the mass production cost can be reduced without affecting the characteristics of the antenna, thereby enabling a safer design. It becomes.

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

  The antenna device according to the present embodiment is used as an antenna for a mobile phone base station, and is used when there is no lightning rod in a building on which an antenna is installed or a steel pipe pillar for mounting an antenna.

  FIG. 1 is a partial longitudinal sectional view of an antenna device showing a preferred embodiment of the present invention.

  As shown in FIG. 1, the antenna device 1 according to the present embodiment includes a ground conductor 2 that becomes a ground potential, a radiating element 3 installed on one surface of the ground conductor 2, and the other surface of the ground conductor 2. A control device 4 installed on the side for controlling the radiating element 3, a radome 5 provided so as to cover the ground conductor 2, the radiating element 3, and the control device 4, and a lightning rod 6 provided on the top of the radome 5, An earth terminal 7 for mainly discharging current from the lightning rod 6 to the ground during a lightning strike is mainly provided.

  The ground conductor 2 is a chassis made of plate-like aluminum. The ground conductor 2 is grounded and becomes a ground potential (ground).

According to JIS standard A4201 described later, aluminum (25 mm ² or more) needs to be larger than copper (16 mm ² or more) with respect to the required cross-sectional area of the ground conductor 2. However, towards the copper (8.96g / cm ³⁾ Aluminum than (2.70g / cm ³⁾ with respect to density much smaller. Therefore, the weight can be reduced by making the ground conductor 2 made of aluminum.

  The ground conductor 2 is formed in an L shape in cross-sectional view by bending its one end (upper side in FIG. 1) 90 degrees. The ground conductor 2 includes a lightning rod connecting portion 2a having a plane facing in the vertical direction and a radiating element installation portion 2b having a plane facing in the horizontal direction. A plurality of mounting holes (not shown) for mounting the radiation element 3 and the control device 4 are formed in the radiation element installation portion 2b.

The ground conductor 2 used as the ground wire has a cross-sectional area of 25 mm ² or more in every part. This is because the cross-sectional area of aluminum required as lightning protection equipment is defined as 25 mm ² or more according to JIS standard A4201, and if the cross-sectional area is less than 25 mm ² , the ground conductor 2 is damaged by the current during lightning strikes. This is because there is a fear.

  On one surface (left side in FIG. 1) of the radiating element installation portion 2b of the ground conductor 2, the radiating element 3 is installed. The radiating element 3 includes a plurality of known antennas such as a plurality of microstrip antennas and a printed dipole antenna.

  The control device 4 is installed on the other surface side (right side in FIG. 1) of the radiating element installation portion 2a of the ground conductor 2. The control device 4 includes known devices such as a phase shifter for controlling the radio wave radiation direction, and a wiring cable for electrically connecting these devices and the radiation element 3 to each other.

  The radiating element 3 and the control device 4 can be variously changed according to the characteristic specification and application of the antenna for a mobile phone base station.

  The radome 5 has a cylindrical shape and is made of FRP (Fiberglass Reinforced Plastics).

  An upper antenna cap 8 is provided at the upper end of the radome 5, and a lower antenna cap 9 is provided at the lower end of the radome 5. Thereby, an antenna internal space 11 surrounded by the radome 5, the upper antenna cap 8, and the lower antenna cap 9 is formed.

  An input connector 12 is provided on the lower surface of the lower antenna cap 9, and the input connector 12 and the control device 4 are connected by a cable 13. The input connector 12 is connected to a radio device (not shown) installed outside the antenna device 1.

  The upper antenna cap 8 is provided with a lightning rod 6 protruding above the upper antenna cap 8.

  A lightning rod base 10 for supporting the lightning rod 6 is installed below the lightning rod 6.

  Between the lightning rod base 10 and the upper antenna cap 8, the lightning rod connection part 2a of the ground conductor 2 is positioned. That is, it arrange | positions so that it may become the lightning rod base 10, the lightning rod connection part 2a, the upper side antenna cap 8, and the lightning rod 6 in order from the bottom, and these are fixed with the metal volt | bolts which are not shown in figure. Thereby, the lightning rod 6 and the lightning rod connection part 2a of the ground conductor 2 are electrically connected.

  A ground terminal seat 7 that penetrates the radome 5 is provided on the side (the right side in FIG. 1) where the control device 4 below the radome 5 is installed.

  The ground terminal seat 7 and the other end of the ground conductor 2 are electrically connected via an inverted U-shaped ground bar 14 in a sectional view.

The earth bar 14 is a metal plate formed separately from the ground conductor 2. In this embodiment, as the earth bar 14, a copper plate having a cross-sectional area of 16 mm ² or more bent in an inverted U shape in a cross-sectional view is used.

  Here, the reverse U-shape in cross-sectional view is that the ground terminal seat is adjusted by adjusting the opening degree of the U-shaped portion even when the distance between the ground terminal seat 7 and the other end of the ground conductor 2 deviates from the design value. This is because 7 and the other end of the ground conductor 2 can be reliably connected. Moreover, the reason why copper is used for the earth bar 14 is that it is easy to process in an inverted U-shape in cross-sectional view, has a small necessary cross-sectional area, and is soft in material, so that the opening degree can be easily adjusted. It is.

Further, the cross-sectional area of the copper plate to a 16 mm ² or more is because the cross-sectional area of the required copper as lightning protection facilities, are provided with 16 mm ² or more in accordance with JIS Standard A 4201, the cross-sectional area is less than 16 mm ² This is because the earth bar 14 may be damaged by a current during a lightning strike.

  The other end of the ground conductor 2 and one end (left side in FIG. 1) of the ground bar 14 are fixed by a metal bolt or welding (not shown), and the other end of the ground bar 14 (right side in FIG. 1) and the ground terminal seat 7 Is fixed by a metal bolt or welding (not shown). Thereby, the ground conductor 2 and the ground terminal seat 7 are electrically connected via the ground bar 14.

  One end of an external ground wire (not shown) is electrically connected to the ground terminal seat 7 outside the radome 5, and the other end of the external ground wire is grounded.

  Here, the shape of the ground conductor 2 will be described in more detail.

  As shown in FIGS. 2 (a) to 2 (c), a mounting hole 21 for connecting the lightning rod 6 is formed in the lightning rod connection part 2 a of the ground conductor 2. In the present embodiment, the two mounting holes 21 are formed so as to be arranged in the lateral direction (the left-right direction in FIG. 2A).

  The radiating element installation part 2b of the ground conductor 2 includes an installation part 22 for installing the radiating element 3 and the control device 4, vertical parts 23a and 23b formed at both ends of the installation part 22 in the horizontal direction, It consists of parallel parts 24a and 24b formed substantially in parallel.

  The other end of the vertical portion 23a is connected to one end of the installation portion 22 in the horizontal direction (upper side in FIG. 2A) so that the installation portion 22 and the vertical portion 23a are substantially vertical. The vertical portion 23a is formed on the side opposite to the side where the lightning rod connection portion 2a is formed (left side in FIG. 2A).

  The other end of the parallel part 24a is connected to one end of the vertical part 23a so that the vertical part 23a and the parallel part 24a are substantially vertical. The parallel portion 24a is formed on the side opposite to the installation portion 22 (upper side in FIG. 2A).

  Similarly, the other end of the installation portion 22 in the horizontal direction is connected to the other end of the vertical portion 23b so that the installation portion 22 and the vertical portion 23b are substantially vertical. The vertical portion 23b is formed on the side opposite to the side where the lightning rod connection portion 2a is formed (left side in FIG. 2A).

  The other end of the parallel part 24b is connected to one end of the vertical part 23b so that the vertical part 23b and the parallel part 24b are substantially vertical. The parallel part 24b is formed on the side opposite to the installation part 22 (the lower side in FIG. 2A).

  The installation part 22, the vertical parts 23a and 23b, and the parallel parts 24a and 24b are integrally formed.

  Accordingly, a recess 25 surrounded by the installation portion 22 and the vertical portions 23a and 23b is formed, and the upper recess 26 surrounded by the vertical portion 23a, the parallel portion 24a, and the radome 5, the vertical portion 23b, and the parallel portion. 24b and a lower concave portion 27 surrounded by the radome 5 are formed.

  In the present embodiment, the radiating element 3 is installed in the recess 25, and the control device 4 is installed on the opposite side.

  The ground conductor 2 may be formed by pressing or the like.

  Next, the operation of the present embodiment will be described together with the operation of the antenna device 1 according to the present embodiment.

  In the antenna device 1 according to the present embodiment, the one end portion of the ground conductor 2 and the lightning rod 6 are electrically connected, and the other end portion of the ground conductor 2 and one end of the ground terminal seat 7 are electrically connected, The other end of the earth terminal seat 7 is grounded via an external earth wire.

  When a lightning strike occurs on the lightning rod 6 of the antenna device 1, the current caused by the lightning strike passes through the lightning rod 6, the conductor 2, and the ground terminal seat 7, and escapes to the ground via an external ground wire connected to the ground terminal seat 7.

  That is, in the antenna device 1 according to the present embodiment, the ground conductor 2 is used as the ground wire, so that a large current during a lightning strike is released to the ground. Thereby, the building under the antenna, the radio connected to the antenna device 1 and the like can be protected.

  Furthermore, since the ground conductor 2 is used as a ground wire, it is not necessary to separately install a ground wire in the antenna internal space 11. Therefore, it is not necessary to consider wiring when installing the ground wire in the antenna internal space 11, work efficiency when the antenna device 1 is manufactured can be improved, and mass production costs can be reduced.

  Moreover, since the antenna device 1 uses the ground conductor 2 conventionally used as a ground wire, the characteristics of the radiating element 3 are not affected.

  Furthermore, in the antenna device 1 according to the present embodiment, the ground conductor 2 and the ground terminal seat 7 are electrically connected via the ground bar 14.

  When the distance between the other end portion of the ground conductor 2 and the ground terminal seat 7 is long, the other end portion of the ground conductor 2 is bent and the other end portion of the ground conductor 2 and the ground terminal seat 7 are directly connected. The processing of the ground conductor 2 becomes complicated. Furthermore, when the other end of the ground conductor 2 and the ground terminal seat 7 are directly connected, the wiring of the control device 4 may be complicated.

  In the antenna device 1, the ground conductor 2 and the ground terminal seat 7 are electrically connected via the ground bar 14, whereby the distance between the other end of the ground conductor 2 and the ground terminal seat 7 is large. However, since it is not necessary to perform complicated processing on the ground conductor 2 and the wiring of the control device 4 is not complicated, work efficiency can be improved.

  Further, in the conventional structure in which the lightning rod 6 and the ground terminal seat 7 are connected by a ground wire, the ground wire is complicated and there is no space in the antenna internal space 14, so that the cross-sectional area of the ground wire is increased. Was difficult.

  In the antenna device 1, the ground conductor 2 is used as a ground wire. Thereby, since it becomes unnecessary to wire a ground wire using the empty space of the antenna internal space 11, the cross-sectional area of the ground conductor 2 can be increased. That is, the cross-sectional area of the ground conductor 2 can be designed to exceed the required cross-sectional area according to JIS standard A4201, and a safer design can be achieved.

  Moreover, in the antenna device 1 according to the present embodiment, both end portions in the horizontal direction of the ground conductor 2 are processed to form the concave portion 25, the upper concave portion 26, and the lower concave portion 27. By forming the upper concave portion 26 and the lower concave portion 27, a space in which the control device 4 can be installed is increased, so that the arrangement of the control device 4 and the wiring design are facilitated. Furthermore, since it processes so that the both ends of the horizontal direction of the ground conductor 2 may be bent, the cross-sectional area of the ground conductor 2 can be enlarged.

  In the said embodiment, although the thing of the shape shown to Fig.2 (a)-(c) was used as the ground conductor 2, it is not limited to this, For example, the ground conductor 30 shown to Fig.3 (a)-(c) May be used.

  As shown in FIGS. 3A to 3C, the ground conductor 30 is further extended at both ends in the horizontal direction of the radiating element installation portion 2b of the ground conductor 2 of FIGS. , 31b.

  In the ground conductor 30, one end of the extension part 31a is connected to one end of the radiating element installation part 2b (upper side in FIG. 3A), and the parallel part 24a and the extension part 31a of the radiating element installation part 2b are substantially vertical. To be. The extension portion 31a is formed on the lightning rod connection portion 2a side (the right side in FIG. 3A).

  Similarly, one end of the extension portion 31b is connected to the other end of the radiating element installation portion 2b so that the parallel portion 24b and the extension portion 31b are substantially vertical.

  In the ground conductor 30, the extension portions 31 a and 31 b are further formed at both ends of the ground conductor 2 in the horizontal direction. Therefore, JIS standard A4201 can be sufficiently satisfied and a safer design can be achieved.

  In the above embodiment, a chassis made of aluminum is used as the ground conductor 2, but a chassis made of other metal such as copper or steel may be used. However, since JIS standard A4201 defines the required cross-sectional area as a lightning protection device according to the material, care is required.

  Moreover, although the copper plate was used as the ground bar 14 in the said embodiment, you may use other metal plates, such as a steel plate. However, since JIS standard A4201 defines the required cross-sectional area as a lightning protection device according to the material, care is required.

  Furthermore, in the above embodiment, the lightning rod 6 and the ground conductor 2, the ground conductor 2 and the ground bar 14, and the ground bar 14 and the ground terminal seat 7 are fixed with metal bolts. You may fix using other fixing methods, such as welding.

  In the above embodiment, the ground conductor 2 and the ground terminal seat 7 are electrically connected via the ground bar 14, but the distance between the ground conductor 2 and the ground terminal seat 7 is short, and the wiring of the control device 4 is complicated. If not, the ground conductor 2 may be processed, and the ground conductor 2 and the ground terminal seat 7 may be directly connected and electrically connected.

  Furthermore, in the said embodiment, although the two attachment holes 21 arranged in a horizontal direction were formed in the lightning rod connection part 2a of the ground conductor 2, the quantity and arrangement direction of the attachment holes 21 may be determined arbitrarily.

  In the above embodiment, the lightning rod base 10 is separated from the upper antenna cap 8 and the ground conductor 2, but the lightning rod base 10 may be formed integrally with the upper antenna cap 8 and the ground conductor 2.

It is a fragmentary longitudinal cross-sectional view of the antenna device which concerns on suitable embodiment of this invention. 2A is a cross-sectional view taken along line 2A-2A in FIG. 1, FIG. 2B is a cross-sectional view taken along line 2B-2B, and FIG. 2C is a perspective view of a ground conductor used in the antenna device according to the present embodiment. FIG. 3A is a cross-sectional view taken along line 2A-2A of a ground conductor used in a modification of the antenna device according to the present embodiment, FIG. 2B is a cross-sectional view taken along line 2B-2B, and FIG. 3C is a perspective view. FIG. It is a partial longitudinal cross-sectional view of the conventional antenna apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna apparatus 2 Ground conductor 3 Radiating element 4 Control apparatus 5 Radome 6 Lightning rod 7 Ground terminal seat

Claims (3)

  A ground conductor, a radiating element installed on one surface of the ground conductor, a control device installed on the other surface side of the ground conductor to control the radiating element, the ground conductor, the radiating element, and the control An antenna device comprising a radome provided so as to cover a device, a lightning rod provided on an upper portion of the radome, and an earth terminal seat for releasing current from the lightning rod to the ground during a lightning strike, An antenna device, wherein one end portion and the lightning rod are electrically connected, and the other end portion of the ground conductor and the ground terminal seat are electrically connected.   The antenna device according to claim 1, wherein the ground conductor and the ground terminal seat are electrically connected via a metal plate formed separately from the ground conductor. The antenna device according to claim 1 or 2, wherein the ground conductor is a chassis made of aluminum having a cross-sectional area of 25 mm ² or more.

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