JPH08330823A - Antenna - Google Patents

Abstract

PURPOSE: To provide an antenna whose protruding dimension from an installation surface is small and which can finely be installed. CONSTITUTION: Two radiation boards 12 are arranged oppositely on one surface of one ground board 11. In the respective radiation boards 12, center parts are connected to the ground board 11 in the same potential and feeding points 12a are provided for parts different from the center parts. Namely, two antenna elements E1 and E2 sharing the ground board 11 are formed. The cover 13 of plastic covers the ground board 11 in a form covering the radiation board 12, and the antenna main body 10 is formed. The antenna main body 10 is mechanically connected to a fitting base 20 fixed to the installation surface such as a ceiling surface and a wall surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to an antenna installed on an indoor ceiling surface or wall surface.

[0002]

2. Description of the Related Art Conventionally, indoor antennas that are fixed to an installation surface such as a ceiling surface or a wall surface have been provided. As a typical antenna of this type, there is a so-called sleeve antenna in which an antenna element is formed in a rod shape. As shown in FIG. 12, from a rectangular parallelepiped pedestal G fixed to an installation surface to an installation surface. The antenna element E'is installed so as to project in a direction substantially orthogonal to the. Here, the antenna element E ′ provided with two antenna elements is shown.
The pedestal G has protrusions H on both sides, and is fixed to the installation surface by screwing a mounting screw I such as a wood screw inserted into a screw insertion hole formed in the protrusion H to the ceiling or wall. It is like this.

[0003]

In the sleeve antenna as described above, the protruding size of the antenna element E'from the installation surface becomes large, so that there is a problem in that it is easily noticeable and impairs the aesthetics of the indoor space. In particular, when the antenna element E ′ is hung from the ceiling surface when it is installed on the ceiling surface, it is assumed that a person may hit the tip of the antenna element E ′ in a place where the ceiling is low, which is not always safe. Not expensive.

In addition, when used in an environment where radio waves are likely to be reflected in the surroundings such as inside a building or in an underground mall, radio waves interfere with each other so that the intensity of the radio waves is weakened by setting the half wavelength to a minimum interval. Since a phenomenon called fading in which the reception intensity changes with the passage of time is likely to occur, an antenna that is not easily affected by fading is required when the main grounding place is indoors.

The present invention has been made in view of the above circumstances, and an object thereof is that a projecting dimension from an installation surface is smaller than that of a conventional one, the apparatus can be installed neatly, there is almost no danger of hitting a person, and the influence of fading is exerted. To provide an antenna that is difficult to receive.

[0006]

In order to achieve the above-mentioned object, in the invention of claim 1, two sheets are arranged in parallel so as not to overlap in the thickness direction and each of which has a feeding point at a portion different from the central portion. A radiation plate; and a ground plate that is arranged parallel to the radiation plates and that is opposed to the radiation plate on one side with a predetermined distance and that is electrically connected to the central portion of the radiation plate.
The antenna element is provided, the surface of the grounding plate opposite to the radiation plate side is provided with a mechanical fixing means for the installation surface, and the radiation plate side of the grounding plate is formed of a radio wave transmitting material covering the radiation plate. A cover is provided.

According to a second aspect of the present invention, in the first aspect of the present invention, the line connecting the feeding points of both radiation plates and the center of the ground plate is on a straight line, and the power feeding of both radiation plates is performed with respect to the center of the ground plate. The feature is that the points are located outside. According to a third aspect of the present invention, in the first or second aspect of the invention, one of the outer side surfaces of the cover, which is on the vertical bisector of the straight line connecting the feeding points of the radiation plates in the plane parallel to the ground plate, A feature is that a mark indicating the mounting direction of the antenna element is provided at the location.

According to a fourth aspect of the present invention, in the first to third aspects of the invention, air flows between the inside and the outside surrounded by the ground plate and the cover at the lowermost portion of the cover when the cover is installed. A breathing hole that enables According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, a concave portion that is fixed to the installation surface and that opens in a circular shape is formed on the surface opposite to the installation surface, and the antenna element and the antenna element A mounting base that serves as the above-mentioned fixing means is provided by holding a part of the antenna main body that is a cover in a fitted state, and an opening window through which a line connected to each antenna element can be inserted is formed in the mounting base. A hook plate arranged along the circumferential direction of the antenna main body is provided on one of the inner bottom surface of the concave portion of the base and the ground plate facing the inner bottom surface of the concave portion of the antenna main body, and the antenna main body is mounted on the other side as the mounting base. On the other hand, there is provided a locking plate that engages with the hooking plate when rotated relatively in the circumferential direction.

[0009]

According to the structure of the invention of claim 1, the space diversity function is provided by providing the two antenna elements in the form in which the one ground plate is shared by the two radiation plates. Therefore, the influence of fading can be reduced. Further, by providing a radiation plate parallel to the ground plate, and by providing a mechanical fixing means to the installation surface on the surface of the ground plate opposite to the radiation plate side,
Compared with the sleeve antenna, the protruding size from the installation surface is smaller, and since the radiation plate is covered with the cover, it can be installed with a good appearance, and furthermore, it can be installed safely without being caught by a person.

According to the structure of the second aspect of the invention, the center of the ground plate is located between the feeding points of the radiation plates, and the feeding points of the radiation plates of each radiation plate are viewed from the center of the ground plate. Since it is located outside the center, the distance between the feeding points of the radiation plate, that is, the distance between the antenna elements can be made relatively large within the limited area of the ground plate. As a result, the effect of space diversity for a desired wavelength can be realized with a relatively small antenna.

According to the structure of the third aspect of the present invention, since the mark indicating the mounting direction of the antenna element is provided at one place on the outer surface of the cover, the orientation of the antenna is set to a desired orientation according to the surrounding environment. The work to do becomes easy. According to the configuration of the invention of claim 4, a breathing hole that allows air to flow between the inside and the outside surrounded by the ground plate and the cover is provided at the lowermost portion of the cover when the cover is installed. Therefore, even if the air in the internal space surrounded by the ground plate and the cover expands and contracts due to the change in the ambient temperature, the air can escape to the outside and the deformation of the ground plate and the cover can be prevented. Further, since the breathing hole is provided at the bottom of the cover, it is difficult for moisture to enter the internal space even if dew condensation occurs.

According to the fifth aspect of the invention, the mounting base is provided as the fixing means, the line connected to the antenna element is passed through the opening window formed in the mounting base, and the antenna body is engaged with the mounting base. Therefore, the mounting base is fixed to the ground plane, the line is electrically connected to the antenna element with the line pulled out from the opening window, and then the antenna body is fixed to the ground plane via the mounting base. be able to. As a result, the work is facilitated during construction.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 and 2, an antenna according to this embodiment comprises an antenna body 10 and a mounting base 20 as a fixing means for holding the antenna body 10 fixed to a ceiling surface or a wall surface. Hereinafter, a case where the antenna is attached to the ceiling will be described.

The antenna body 10 includes a pair of antenna elements E.
Equipped with ₁ , E ₂ . Each of the antenna elements E ₁ and E ₂ includes a disk-shaped ground plate 11 shared by both antenna elements E ₁ and E ₂ , and is arranged substantially parallel to the ground plate 11 while being separated in the thickness direction of the ground plate 11. A radiation plate 12 made of a disk-shaped conductor plate having a diameter smaller than that of the ground plate 11 is provided for each of the antenna elements E ₁ and E ₂ . Both radiation plates 12 are arranged on substantially the same plane. It is desirable to use stainless steel for the ground plate 11 in consideration of rust prevention performance, but it is also possible to use aluminum or brass as long as it is a conductive material.

A cover 13 made of a thermoplastic synthetic resin is attached to one side of the ground plate 11 in the thickness direction where the radiation plate 12 is arranged. The cover 13 is formed in a bowl shape and has a circular opening. In addition, bosses 13a are provided at four locations on the inner peripheral portion of the cover 13 at substantially equal intervals in the circumferential direction, and screws provided on the ground plate 11 are provided in boss holes (not shown) formed in each boss 13a. The ground plate 11 is covered with the cover 13 by screwing the tip ends of the fixing screws 14 made of tapping screws through the insertion holes 11a (see FIG. 3C).
Are combined. Further, a positioning protrusion 13c serving as a mark having an insertion hole 13b at one location on the outer peripheral surface of the cover 13.
Is projected. A breathing hole 13d that communicates with the inside and outside is formed at the lower end of the cover 13 to allow air to flow between the internal space surrounded by the ground plate 11 and the cover 13 and the outside. Since this breathing hole 13d is located at the bottom when the antenna body 10 is attached to the ceiling, it is difficult for moisture to enter the internal space even if dew condensation occurs. In order to have the same function when the antenna main body 10 is attached to the wall, in the antenna main body 10 for the wall, the breathing hole 13d is formed on the side surface of the cover 13.
Is preferably formed.

The antenna elements E ₁ and E ₂ will be described in more detail. As shown in FIG. 3, two screws 15 made of a conductive material are inserted into the ground plate 11 at a position away from the center, and the tip end surface of the cylindrical spacer 16 inserted into the screw 15 and the screw 15 are inserted. The center part of the radiation plate 12 is sandwiched between the center part of the radiation plate 12 and the nut 17 screwed to the tip part of the. That is, each radiating plate 12 is opposed to be parallel to the ground plate 11 with a certain distance from the ground plate 11 via the spacer 16, and the substantially central portion of the radiating plate 12 is connected via the screw 15 to the ground plate 11. It is electrically connected to. Further, the feeding point 12a is set at a portion on the straight line connecting the centers of both the radiation plates 12 and different from the center of each radiation plate 12.
The tip of the feeding pin 33, which is the central conductor of the coaxial connector 30 fixed to the grounding plate 11, is connected to the feeding points 12a of the second portion 2 with solder. A cylindrical holder 34 is inserted into the power supply pin 33 to keep the radiation plate 12 together with the spacer 16 substantially parallel to the ground plate 11. That is, the ground plate 11 and the radiation plate 12 form a so-called top-load type antenna. Here, as shown in FIG. 3 (c), the feeding points 12 a of the radiation plates 12 are provided outside the centers of the radiation plates 12 as viewed from the center of the ground plate 11, and between the feeding points 12 a. Distance L
Is set to be λ / 2 or more when the wavelength used is λ. Therefore, the effect of space diversity can be obtained by the antenna elements E ₁ and E ₂ .

The connector 30 is cylindrical and has a cylindrical portion 31 in which an external thread portion 31a is formed on the outer peripheral surface of one end portion in the axial direction.
And a square mounting flange 32 is formed at the other axial end of the tubular portion 31. The connector 30 is fixed to the ground plate 11 by screwing the mounting screws 35 inserted into the four corners of the mounting flange 32 into the ground plate 11. That is, the tubular portion 31 and the mounting flange 32 are electrically connected to the ground plate 11. Further, the tubular portion 31 is the ground plate 1
It projects to the side opposite to the radiation plate 12 with 1 in between. That is, the connector 30 exposes the tubular portion 31 to the outside of the cover 13. Further, the above-described power supply pin 33 is provided coaxially with the tubular portion 31.

The ground plate 11 is provided with a pair of hook plates 18 for mechanically coupling with the mounting base 20 on the same surface as the connecting portion of the connector 30. The hooking plate 18 is formed in a shape having a strip-shaped base piece 18a and a substantially L-shaped hooking claw piece 18b that is integrally continuous with one end of the base piece 18a in the longitudinal direction. A mounting screw 19 screwed into the ground plate 11 and the above-mentioned fixing screw 14 can be inserted into each end of the base piece 18a in the longitudinal direction (see FIG. 2).
8 is a ground plate 11 with a mounting screw 19 and a fixing screw 14.
Fixed to. With the hooking plate 18 fixed to the ground plate 11, the tip of the hooking claw piece 18b is located away from the ground plate 11.

As described above, the antenna body 10 is formed to have an appearance as shown in FIG. 4, is provided with a pair of antenna elements E ₁ and E ₂ having the ground plate 11 in common, and each antenna element E ₁ , E. _{The second} radiation plate 12 (see FIG. 3) is covered with a cover 13 serving as a radome, and the connector 30 is exposed on one surface side of the ground plate 11 which is not covered with the cover 13. Furthermore, a hook plate 18 for mechanical connection with the mounting base 20 is also provided.

Next, the mounting base 20 will be described.
As shown in FIGS. 5 and 6, the mounting base 20 is formed of a synthetic resin in a shallow bottomed cylindrical shape having an opening on the lower surface side, and has an inner diameter approximately equal to the outer diameter of the upper end portion of the antenna body 10 described above. There is. That is, a recess into which the upper portion of the antenna body 10 is fitted is formed on the lower surface side of the mounting base 20.

A pair of guide grooves 20a opening in an arc shape are formed in the inner bottom surface of the mounting base 20 corresponding to the hooking plates 18 provided on the antenna body 10, and a part of the opening of the guide groove 20a is formed. The locking plate 21 is fixed so as to straddle the width direction. The locking plate 21 is formed in a strip shape, and one end in the longitudinal direction is inserted into a protrusion 20b provided on the outer peripheral side of the mounting base 20 with respect to the guide groove 20a, and a tapping screw inserted into the other end. It is fixed to the mounting base 20 by screwing the fixing screw 22 made of the screw into the inner peripheral side of the mounting base 20 with respect to the guide groove 20a. The guide groove 20a has a width dimension and a depth dimension into which the hooking claw piece 18b can be inserted. After the antenna body 10 is fitted into the mounting base 20 and the hooking claw piece 18b is aligned with the guide groove 20, the hooking claw piece is formed. When the antenna body 10 is rotated so that 18b is locked by the locking plate 21, the antenna body 10 can be coupled to the mounting base 20.

Further, a positioning projection 20c is formed on the outer peripheral surface of the mounting base 20 in a state where the hooking claw piece 18b is locked by the locking plate 21 and which is aligned with the positioning projection 13c provided on the cover 13. An insertion hole 20d is formed through the positioning protrusion 20c, and a nut 23 (see FIG. 5A) is embedded in the upper end of the positioning protrusion 20c.
Therefore, if the screw is inserted into the insertion holes 13b and 20d and screwed into the nut 23 after the antenna body 10 is coupled to the mounting base 20, the antenna body 10 is attached to the mounting base 20.
Will be securely fixed. Also, the positioning protrusion 1
By providing 3c and 20c in one place, the positioning of the antenna main body 10 with respect to the mounting base 20 becomes easy. Here, the position of the positioning protrusion 13c is
It is formed on a straight line orthogonal to the straight line connecting the feeding points 12a of the radiation plates 12 of both antenna elements E ₁ and E _{2 in} the plane parallel to the ground plate 11.

By the way, the connector 30 provided on the antenna main body 10 has a pair of connector insertion holes as opening windows through which a line is inserted, each opening in a fan shape in a portion different from the guide groove 20a in the bottom wall of the mounting base 20. It is inserted through the hole 24. As shown in FIG. 2, a coaxial connector 37 provided at one end of a coaxial cable 36 as a line is coupled to each connector 30. In addition, one connector insertion hole 2
A hook 24a is formed on the inner peripheral portion of the hook 4.
A fall prevention string 25 can be attached between 4a and the connecting hole 18c formed in the hook claw piece 18b of the hook plate 18. An annular hooking ring 25 is provided at one end of the captive string 25.
a is attached, and a hook-shaped hooking hook 25b is attached to the other end. Therefore, the hook ring 25a is hooked on the hook 24a, and the hook hook 25 is hooked on the connecting hole 18c.
By hooking b, it is possible to prevent the antenna main body 10 from falling off when the connectors 30 and 37 are attached / detached (particularly at the time of coupling), and the work can be performed easily.
Further, as described above, the hook ring 25a is attached to the hook 24a.
Since the hooks 25 are simply hooked on the hooks 25b and the hooks 25b are hooked on the connecting holes 18c, the cap 25 can be easily removed after the connectors 30 and 37 are joined or separated.

Next, a method of mounting the mounting base 20 on the installation surface will be described. Mounting base 20 in this embodiment
Is configured so that various mounting methods can be selected. First, the case of attaching to a panel-shaped member such as a ceiling panel or a wall panel will be described. FIG. 7B shows a sandwich metal fitting 41 used for mounting on a relatively thin panel-shaped member, and is formed on the outer peripheral portion of the upper surface of the mounting base 20 as shown in FIG. 7A. Are attached to the pair of metal fitting mounts 26. Bracket mount 2
A pair of holding grooves 26a is formed on the upper surface of the mounting base 20 along the diametrical direction of the mounting base 20, and each holding groove 26a is formed such that the outer peripheral side of the mounting base 20 is wider than the inner peripheral side. Further, between both holding grooves 26a provided in each metal fitting mounting base 26, a so-called daruma-hole-shaped screw holding hole 26b in which the outer peripheral side of the mounting base 20 is formed wider than the inner peripheral side is formed. ing. On the other hand, the sandwiching metal piece 41 is formed in a shape in which a substantially U-shaped mounting spring piece 41b that opens downward from a tip edge of one of the substantially L-shaped base pieces 41a extends continuously and integrally. The fixing screw 4 inserted into the base piece 41a from the lower surface side of the mounting base 20 through the screw holding hole 26b.
Two screw holes 41c to be screwed are formed. Base 41
From the tip edge of the other piece of a, a holding piece 41d formed in a substantially L shape in the piece is provided so as to project downward.

When the fixing screw 42 is loosely screwed into the screw hole 41c, the holding piece 41d is inserted into the wide portion of the holding groove 26a and slid into the narrow portion, so that the holding metal fitting 41 is attached to the mounting base 41. It is temporarily held at 20. On the other hand, a circular mounting hole having a diameter slightly smaller than the distance between the holding spring pieces 41b of the sandwiching metal fittings 41 is bored in the panel material constituting the ceiling or the wall. Here, both clamping metal fittings 41 are inserted into the mounting holes while the fixing screws 42 are loosened, and then the fixing screws 42 are tightened, whereby the clamping metal fittings 41 are attached.
At the same time as fixing to 0, the peripheral portion of the mounting hole can be sandwiched between the outer peripheral portion of the upper surface of the mounting base 20 and the tip portion of the holding spring piece 41b, and as a result, the mounting base 20 becomes a panel-shaped member. It can be fixed. Upon removal, the fixing screw 42 is loosened and the fixing screw 42 is slid along the screw holding hole 26b toward the outer peripheral side of the mounting base 20, and the head of the fixing screw 42 reaches the large diameter portion of the screw holding hole 26b. At this time, the fixing screw 42 can be removed from the mounting base 20 together with the sandwiching metal fitting 41.

The sandwiching metal fitting 43 shown in FIG. 8 (b) is substantially L instead of the holding spring piece 41b of the sandwiching metal fitting 41 shown in FIG.
One of the character-shaped base pieces 43a is formed to extend along the upper surface of the mounting base 20 and sandwiching pieces 43b projecting from both side edges of the tip end portion. Other configurations are similar to those of the sandwich metal fitting 41 shown in FIG. 7, the base piece 43a has a screw hole 43c, and the other piece of the base piece 43a is provided with a holding piece 43d. Here, the sandwiching piece 43b is inclined so that it approaches the upper surface of the mounting base 20 toward the tip end side.

The method of attaching and detaching to the panel material constituting the ceiling or the wall by using the sandwich metal fitting 43 is as follows.
It is similar to the sandwiching metal fitting 41 shown in FIG. 7. The sandwich metal fitting 43 is suitable for mounting on a member having a small thickness.
The sandwich metal fitting 44 shown in FIG. 9 can be used regardless of the thickness of the panel-shaped member. The sandwich metal fitting 44 includes a cylindrical pillar 45 having an opening on one side and a pillar 4
5, a tightening screw 46 rotatably supported at both upper and lower ends.
And a sandwich plate 47 screwed to the tightening screw 46. Fixing pieces 45a are provided on both sides of the lower end of the column 45 in FIG. 9, and the holding groove 2 is provided on the lower surface of the fixing piece 45a.
A fixed projecting piece (not shown) inserted into 6a is projected. That is, by inserting a fixing protrusion protruding from the lower surface of the fixing piece 45a into the holding groove 26a, the support column 45 is fixed to the mounting base 20 with its opening surface facing outward. A retraction notch 45b is formed at the upper end of one side wall adjacent to the opening surface of the column 45. Sandwich plate 47
Is prevented from rotating by both side walls adjacent to the opening surface of the column 45, and the pinch plate 47 moves the column 45 up and down with the tip end protruding from the opening surface of the column 45 as the tightening screw 46 rotates. Moving. Further, when the clamping plate 47 reaches the position corresponding to the retracting notch 45b while the clamping screw 46 is rotated in the loosening direction and the clamping plate 47 is moving upward, the clamping plate 47 becomes the retracting notch 45b. Will be introduced. That is, the tip of the sandwiching plate 47 faces in the circumferential direction of the mounting base 20.

Therefore, when the mounting base 20 is fixed to the panel-shaped member by using the sandwiching metal fitting 44, the sandwiching metal fitting 44 is introduced into the retracting notch 45b, and the sandwiching metal fitting 44 is punched in the panel-shaped member. Insert it into the mounting hole. After that, when the tightening screw 46 is tightened, the sandwich plate 47
Comes out of the notch 45b for evacuation, and the tip portion projects from the opening surface of the column 45. Therefore, by further tightening the tightening screw 46, the sandwiching plate 47 comes closer to the upper surface of the mounting base 20, and the peripheral portion of the mounting hole is separated between the upper surface of the mounting base 20 and the tip of the sandwiching plate 47. It can be pinched. To remove the mounting base 20,
The tightening screw 46 may be loosened and the sandwiching plate 47 may be retracted to the retracting notch 45b.

By the way, the mounting base 20 is mounted on a switch box or the like used when mounting wiring equipment such as a switch or an outlet, in addition to mounting on the ceiling or wall using the above-mentioned sandwiching metal fittings 41, 43, 44. Or it can be attached directly to the ceiling or wall. The switch box is generally embedded in a wall and has an opening surface that is substantially flush with the wall surface. Since the tongue piece having the screw hole is provided on this opening surface, the screw insertion holes 27a and 27b provided in the mounting base 20 are provided.
The mounting base 20 can be fixed to the switch box by screwing the box screw through the screw hole provided in the switch box. Here, the one screw insertion hole 27a is a so-called daruma hole in which a narrow width portion and a wide width portion are continuous, and the interval between the box screws inserted into both the screw insertion holes 27a and 27b can be adjusted. Further, when directly attached to the ceiling or wall, a fixture such as a wood screw may be fixed to the ceiling or wall through the screw insertion hole 28 formed in the outer peripheral portion of the mounting base 20.

The above-mentioned antenna is, for example, a PHS (Pe
rsonal Handy-phone System) can be used as an antenna for a base station. For example, as shown in FIG. 10 and FIG. 11, two antennas A described above are provided, and both antennas A are connected via an RF switch box B to a BS main C that converts a wireless signal and a wired signal. The BS main C performs mutual conversion between a radio signal transmitted / received between the PHS telephone D and the antenna A and a wired signal transmitted through a general telephone line 54. Each antenna A is provided with two antenna elements E _1, E ₂ to have a function of space diversity, each antenna element E _1, E
Every _two are connected to the RF switch box B using the coaxial cable 36. The RF switch box B includes four antennas for amplifying received signals for each antenna element E ₁ and E _2.
One amplifier 51 is provided, and one amplifier 52 for amplifying a transmission signal is shared by all the antenna elements E ₁ and E ₂ . Further, four changeover switches 53 are provided so that the antenna elements E ₁ and E ₂ are selectively connected to the amplifier 51 and the amplifier 52. Here, of the signals received by the _two antenna elements E ₁ and E ₂ of each antenna A, the one having the better reception condition is adopted.

[0031]

According to the first aspect of the present invention, since the two antenna elements in which the two ground plates share one ground plate are provided, the function of space diversity can be provided. There is an advantage that the influence of fading can be reduced. Also, a radiation plate parallel to the ground plate is provided,
Since the surface of the ground plate opposite to the radiation plate side is provided with a mechanical fixing means for the installation surface, the projecting dimension from the installation surface becomes smaller than that of the sleeve antenna.
In addition, since the radiation plate is covered with the cover, the radiation plate can be installed with a good appearance, and further, there is an effect that a person can safely install the antenna without being caught by the antenna.

According to a second aspect of the present invention, the center of the ground plate is located between the feeding points of the radiation plates, and the feeding points of the radiation plates are located closer to the center of each radiation plate when viewed from the center of the ground plate. Since it is located outside, the distance between the feeding points of the radiation plate, that is, the distance between the antenna elements can be made relatively large within the limited area of the ground plate. As a result, there is an advantage that the effect of space diversity for a desired wavelength can be realized with a relatively small antenna.

According to the third aspect of the present invention, since the mark indicating the mounting direction of the antenna element is provided at one location on the outer side surface of the cover, it is easy to set the orientation of the antenna to a desired orientation according to the surrounding environment. Has the advantage that According to the invention of claim 4, in the portion which becomes the lowermost part in the cover when installed,
The air inside the space surrounded by the ground plate and the cover expands due to changes in ambient temperature because the breathing holes that allow air to flow between the inside and the outside are surrounded by the ground plate and the cover. Even if it contracts, it can be released to the outside, and the deformation of the ground plate and the cover can be prevented. Further, since the breathing hole is provided at the bottom of the cover, there is an advantage that it is difficult for moisture to enter the internal space even if dew condensation occurs.

According to the fifth aspect of the present invention, since the mounting base is provided as the fixing means, the line connected to the antenna element is passed through the opening window formed in the mounting base, and the antenna main body is engaged with the mounting base. It is possible to fix the mounting base on the ground, electrically connect the line to the antenna element with the line pulled out from the opening window, and then fix the antenna main body to the ground plane via the mounting base. As a result, there is an advantage that the work becomes easy at the time of construction.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state in which an antenna body and a mounting base are removed in an embodiment.

FIG. 2 is a perspective view showing a state in which an antenna body and a mounting base are removed in the embodiment.

3A and 3B show an antenna element used in Examples, where FIG. 3A is a plan view, FIG. 3B is a side view, and FIG. 3C is a bottom view.

4A and 4B show an antenna main body used in Examples, FIG. 4A is a plan view, FIG. 4B is a side view, and FIG. 4C is a bottom view.

5A and 5B show a mounting base used in Examples, FIG. 5A is a plan view, FIG. 5B is a side view, and FIG. 5C is a bottom view.

FIG. 6 is a perspective view of a mounting base used in the embodiment.

7 (a) is a perspective view of the mounting base of the embodiment in which the sandwich metal fitting is attached, and FIG. 7 (b) is a perspective view of the sandwich metal fitting used in FIG. 7 (a).

FIG. 8A is a perspective view of the mounting base of the embodiment with another sandwich metal fitting attached thereto, and FIG. 8B is a perspective view of the sandwich metal fitting used in FIG. 8A.

FIG. 9A is a perspective view showing a state in which another sandwich metal fitting is attached to the mounting base of the embodiment, and FIG. 9B is a perspective view of the sandwich metal fitting used in FIG. 9A.

FIG. 10 is a block diagram of a PHS base station using the present invention.

FIG. 11 is a block diagram of a main part of a base station of PHS using the present invention.

FIG. 12 is a perspective view showing a conventional example.

[Explanation of symbols]

10 Antenna Main Body 11 Grounding Plate 12 Radiating Plate 12a Feeding Point 13 Cover 13c Positioning Protrusion 13d Breathing Hole 18 Hooking Plate 20 Mounting Base 21 Locking Plate 36 Coaxial Cable E ₁ , E ₂ Antenna Element

Claims (5)

[Claims] 1. A power supply point is provided at a portion different from the central portion and arranged in parallel so as not to overlap in the thickness direction.
Two radiating plates, and one grounding plate that is arranged in parallel with both radiating plates facing each other on one surface side with a predetermined distance and is electrically connected to the center of the radiating plate The antenna element is provided, the surface of the ground plate opposite to the radiation plate side is provided with a mechanical fixing means for the installation surface, and the radiation plate side of the ground plate is formed of a radio wave transmitting material that covers the radiation plate. An antenna characterized by comprising a cover. 2. The line connecting the feeding points of both radiation plates and the center of the grounding plate is on a straight line, and the feeding points of both radiation plates are located outside the center of the grounding plate. The antenna according to claim 1, which is characterized in that. 3. A mark indicating the mounting direction of the antenna element is provided at one location on the outer surface of the cover on the perpendicular bisector of the straight line connecting the feeding points of both radiation plates in the plane parallel to the ground plate. The antenna according to claim 1 or 2, characterized in that. 4. A breathing hole for allowing air to flow between an internal space surrounded by the ground plate and the cover and the outside is provided at a lowermost portion of the cover when the cover is installed. The antenna according to any one of claims 1 to 3. 5. A recessed portion which is fixed to the mounting surface and opens in a circular shape is formed on a surface opposite to the mounting surface, and a part of an antenna main body including an antenna element and a cover is fitted in the recessed portion. A mounting base that serves as the fixing means by holding is provided, and an opening window through which a line connected to each antenna element can be inserted is formed in the mounting base. One of the ground plate facing the inner bottom surface is provided with a hook plate arranged along the circumferential direction of the antenna body, and the other is provided when the antenna body is rotated in the circumferential direction relative to the mounting base. The antenna according to claim 1, further comprising: a locking plate that engages with the hooking plate.