WO2011132642A1

WO2011132642A1 - Uhf band antenna

Info

Publication number: WO2011132642A1
Application number: PCT/JP2011/059552
Authority: WO
Inventors: 金子　敦; 靖人関口
Original assignee: 八木アンテナ株式会社
Priority date: 2010-04-20
Filing date: 2011-04-18
Publication date: 2011-10-27

Abstract

Disclosed is a UHF band antenna, wherein a radiation element of an antenna is formed by using a plate-shaped conductive member to form antenna elements in the horizontal direction on the upper and lower sides, coupling the antenna elements by means of a coupling line, and forming openings in the upper and lower parts. A reflection element is provided in a predetermined gap at the rear surface of the radiation element, the plate-shaped conductive member is used to form the reflection element into a frame shape, reflection element sections are formed on the upper and lower sides, and side-section elements are formed on both sides. Holes are provided in the side-section elements which are bent at an angle of 90° toward the rear. A connector is attached to a connector attachment plate provided between the side-section elements in the center of the rear surface of the reflection element. A coaxial cable is connected to a power feed point provided in the coupling line, and the other end of the coaxial cable is connected to the connector to serve as an antenna output.

Description

UHF band antenna

The present invention relates to a UHF band antenna used for terrestrial digital broadcasting and wireless communication. In particular, the present invention relates to a vertically long UHF band antenna.

Digital Terrestrial (TV) Broadcasting (ISTB-T: Terrestrial Integrated Services Digital Broadcasting) uses UHF band radio waves, which use 470 to 770 MHz (13 to 62 channels), mainly horizontally polarized Is used. Against this background, the diversification of antennas has progressed, and the demand for miniaturization has increased, and in particular, miniaturization in the installed state of horizontal polarization reception has been demanded.

Therefore, conventionally, in a UHF band antenna in which a radiating element and a reflector are arranged at a predetermined interval, the radiating element has a linear element disposed horizontally on the outer side in the vertical direction, and the straight line A wide-band antenna with a reflector that can be reduced in size by connecting a linear element with a coupling line and providing a feeding point at the center of the coupling line is considered (for example, see Patent Document 1 below). .

Japanese Unexamined Patent Publication No. 2008-113407

The conventional UHF band receiving antenna has a problem that it is not sufficiently miniaturized and has a large wind receiving area because the width is set to about ½ wavelength. The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a UHF band antenna that can be downsized while ensuring a sufficient gain and can reduce a wind receiving area.

A vertically long UHF band antenna according to the present invention is a UHF band antenna comprising an antenna body in which a reflecting element is arranged opposite to a back surface of a radiating element and a case housing the antenna body.
The radiating element includes a first antenna element and a second antenna element which are arranged with a predetermined interval in a vertical direction in the same plane by a plate-like conductive member, and the first antenna element and the second antenna element. A coupling line that couples to the antenna element; a feeding unit that is provided in a central portion of the coupling line and feeds power to the first antenna element and the second antenna element; and the first antenna element and the second antenna element. A first gap formed in the coupling line between at least one of the antenna elements of the antenna element and the feeding portion,
The reflecting element includes a reflecting element portion provided at a predetermined interval in the vertical direction, a side element provided with a predetermined width on both the left and right sides and bent backward by approximately 90 °, and the side elements. A vertically long hole formed in each of the upper portion and the lower portion, and a second gap portion formed at a position corresponding to the first gap portion provided in the radiation element,
The case for housing the antenna body includes a window at a position corresponding to a first gap formed in the radiating element and a second gap formed in the reflective element.

According to the present invention, the width of the antenna can be narrowed to reduce the wind receiving area, and the case can be provided with a window to allow the wind to pass therethrough, thereby further reducing the wind receiving area. .

FIG. 1 shows an external configuration of an antenna body of a UHF band antenna according to an embodiment of the present invention, FIG. 1 (a) is a perspective view seen from the front direction, and FIG. 1 (b) is a perspective view seen from the rear side. FIG. 2A is a front view of the antenna body according to the embodiment, FIG. 2B is a right side view thereof, and FIG. 2C is a top view thereof. 3A is a rear view of the antenna body according to the embodiment, and FIG. 3B is a right side view thereof. 4A and 4B show a state where the plug attachment plate is attached according to the same embodiment. FIG. 4A is a view of the plug attachment plate viewed from the radiating element side, and FIG. 4B is a side view. . FIG. 5 is an exploded perspective view showing a state where the antenna body according to the embodiment is housed in a resin case. FIG. 6 is a gain characteristic diagram of the UHF band antenna according to the embodiment. FIG. 7 is a VSWR characteristic diagram of the UHF band antenna according to the embodiment. FIG. 8A is a view when the antenna main body according to the embodiment is attached to a stretchable antenna mast installed on a veranda or the like, and FIG. 8B is a diagram illustrating the antenna main body according to the embodiment attached to the antenna mast. It is a figure which shows the form attached and used for.

This embodiment shows an example in which the present invention is applied to a UHF band antenna that receives UHF band radio waves of 470 to 770 MHz.

FIG. 1 shows an external configuration of an antenna main body 10 according to this embodiment, FIG. 1 (a) is a perspective view seen from the front direction, and FIG. 1 (b) is a perspective view seen from the back side. 2A is a front view of the antenna body 10 according to the embodiment, FIG. 2B is a right side view thereof, and FIG. 2C is a top view thereof. 3A is a rear view of the antenna body 10 according to the embodiment, and FIG. 3B is a right side view thereof.

1 to 3, reference numeral 11 denotes a radiating element, and a reflecting element 21 is provided on the back side of the radiating element 11 with a predetermined interval. The radiating element 11 and the reflecting element 21 are supported by support members 31a to 31f provided in two respectively in the top and bottom and the center. The distance D1 between the radiating element 11 and the reflecting element 21 is set to, for example, about 0.078λa. For example, λa indicates the wavelength at the lowest frequency 470 MHz in the used frequency band 470 to 770 MHz. The support materials 31a to 31f are made of an insulator, and are fixed to the radiating element 11 and the reflecting element 21 with screws, for example.

The radiating element 11 uses a plate-shaped conductive member having a total length H1 of 0.815 λa and a lateral width of 0.201 λa, and first and

second antenna elements

12a and 12b are formed in the horizontal direction on both upper and lower sides. The

antenna elements

12a and 12b are coupled by a coupling line 13. In this case, the radiating element 11 forms the

antenna elements

12a and 12b and the coupling line 13 by providing

gaps

14a and 14b having a predetermined shape between the center position and the upper and lower ends. The first antenna element 12a and the second antenna element 12b are formed vertically and symmetrically. The first and

second antenna elements

12a and 12b operate as antennas stacked in two upper and lower stages, and receive horizontally polarized radio waves.

The coupling line 13 is composed of

lines

15a and 15b formed on both sides of the radiating element 11 with a width of W1 (about 0.022λa) and substantially triangular

power supply parts

16a and 16b provided in the center of the radiating element 11. The In this case, the

power feeding portions

16a and 16b are provided at predetermined intervals so that the triangular top portions face each other, and the bottom portions located on both sides are connected to the

lines

15a and 15b. The

lines

15a and 15b are cut off by a length of D2 (about 0.094λa) at the central portion, that is, at a portion connected to the

power feeding portions

16a and 16b. The

power feeding portions

16a and 16b have a bottom width W2 set to a value larger than D2, for example, about 0.188λa, and are connected to the

lines

15a and 15b at both ends of the bottom.

The

antenna elements

12a and 12b have a vertical length H2 of about 0.102λa, the outer corners thereof are notched obliquely, and the inner center (horizontal direction) has a width W3 (about 0). .094λa) is formed in a straight line, and both sides thereof are formed obliquely extending in the direction of the

power feeding portions

16a and 16b. In the

antenna elements

12a and 12b, the distance between the inner position and the horizontal center line of the

power feeding parts

16a and 16b is set to H3 (about 0.306λa), and the extended tip part is connected to the center line of the

power feeding parts

16a and 16b. Is set to H4 (about 0.235λa).

In the radiating element 11, the

lines

15 a and 15 b formed on both sides are bent in the direction of the reflecting element 21 at an angle θ, for example, an angle of about 135 °. At this time, the radiating element 11 has a central portion width W4 of about 0.157λa and a total width W5 viewed from the front of about 0.188λa.
In addition, the

feeding portions

16a and 16b have

feeding points

17a and 17b formed at opposite ends, and the distance between the tips is D3 (about 0.044λa) in the direction of the reflective element 21. Can be bent diagonally. For example, the outer conductor 34 of the feeding coaxial cable 32 having a characteristic impedance of 75Ω is connected to one feeding point 17a by soldering or the like, and the center conductor 33 is connected to the other feeding point 17b. The

power feeding units

16a and 16b feed power to the

antenna elements

12a and 12b through the coupling line 13, and operate as antennas stacked in two stages.

The

antenna elements

12a and 12b are provided with

holes

18a and 18b through which screws for fixing to the resin case are inserted as will be described in detail later.

On the other hand, the reflective element 21 is formed in a frame shape having a total length H11 of about 0.831λa and a lateral width of about 0.235λa using a plate-like conductive member, and has a vertical length of H12 (about 0.031λa) first reflecting element portion 22a and second reflecting element portion 22b are formed, and

side elements

23a and 23b having a lateral width of D11 (about 0.031λa) are formed on the left and right sides. .
That is, the reflective element 21 has a configuration in which a gap is provided at a position facing the

gaps

14 a and 14 b formed in the radiating element 11. The second reflecting element portion 22b located on the lower side is provided with a positioning projection 20 at the center on the back side.

The reflective element 21 has the

side elements

23a and 23b bent rearward, that is, in a direction opposite to the radiating element 11, at an angle of 90 °, and the lateral width W10 after bending is set to about 0.172λa. The

side elements

23a and 23b are notched obliquely at each corner. Further, the

side elements

23a and 23b are provided with holes 24a to 24d formed in a square shape having a height H13 and a lateral width W11, for example, at the upper and lower portions. The holes 24a to 24d have a height H13 of about 0.266λa, a lateral width W11 of about 0.016λa, and a distance H14 from the upper and lower ends of the reflective element 21 of about 0.031λa.

Further, the reflecting element 21 has one side element 23b, that is, the side element 23b on the side corresponding to the power feeding part 16b to which the central conductor 33 of the coaxial cable 32 is connected among the

power feeding parts

16a and 16b of the radiating element 11. The impedance adjustment unit 25 is configured by extending the central portion of the base plate by a predetermined length of L11 (about 0.251λa). That is, the impedance adjusting unit 25 extends the central portion of the side element 23b by a length of L11 from the front surface of the reflecting element 21 by a length of L11, and bends at an angle of 90 ° further inward from the extended position. ing. The value of D12 of the impedance adjusting unit 25 is set to about 0.063λa, and the width D13 of the bent tip is set to about 0.031λa.

By forming the impedance adjusting unit 25 by bending as described above, the depth D14 of the antenna body 10, that is, the depth D14 from the front surface of the radiating element 11 to the rear surface of the plug attachment plate 26 is about 0.11λa.
In addition, a plug attachment plate 26 is attached to the reflecting element 21 between the

side elements

23a and 23b at the center position on the back side. The plug mounting plate 26 is bent on both sides and positioned inside the

side elements

23a and 23b, and is attached to the

side elements

23a and 23b with, for example, rivets or screws. The vertical length H15 of the plug mounting plate 26 is set to about 0.125λa.

The power plug 41 is attached to the central portion of the plug mounting plate 26. 4A and 4B show a state where the plug attachment plate 26 is attached, FIG. 4A is a view of the plug attachment plate 26 viewed from the radiating element 11 side, and FIG. 4B is a side view thereof. is there. The plug attachment plate 26 is cut and raised at the center portion at an angle of θa, for example, an angle of about 135 ° in the outer direction, and the center portion of the cut and raised piece 27 is bent at an angle of 90 ° in the inner direction. Further, the plug mounting plate 26 is formed with a hole 28 for arranging the plug 41 in the portion where the cut and raised piece 27 is provided. Then, the plug 41 is attached to the tip end side of the cut and raised piece 27 so as to face obliquely downward by 45 °. The center conductor and the outer conductor of the connector 41 are connected to the feeding points 17a and 17b of the

feeding parts

16a and 16b by the coaxial cable 32 as shown in FIG.

By attaching the plug 41 obliquely to the tip end side of the cut and raised piece 27 as described above, a coaxial cable (not shown) externally connected to the plug 41 is naturally wired downward, Handleability is improved. *

And the antenna main body 10 comprised as mentioned above is accommodated in the resin case 51 as shown in FIG. FIG. 5 is an exploded perspective view showing a state where the antenna body 10 is housed in the resin case 51.
The resin case 51 includes a front case 52 and a back case 53. The front case 52 and the back case 53 have, for example, a vertically long elliptical window at a position facing the upper gap portion 14a provided in the radiating element 11. 54a and 54b are provided. Further, on the inner side of the back case 53, a mounting base (boss) 55a for mounting the antenna is provided at a position corresponding to the

holes

18a and 18b provided in the first antenna element 12a and the second antenna element 12b of the radiating element 11. 55b is provided at a predetermined height.

Further, a front case mounting base 56 for mounting the front case 52 at a position slightly below the center is provided inside the rear case 53 at a predetermined height. The front case mounting base 56 is provided with a through hole for screw insertion along the central axis. A mounting base (not shown) is provided on the inner side of the front case 52 at a position corresponding to the front case mounting base 56, and the rear case 53 is inserted into the through hole for screw insertion of the front case mounting base 56. A mounting screw is inserted from the back surface of the front side, and a tip thereof is screwed to a mounting base portion on the front case 52 side to fix the front case 52 and the rear case 53.
Further, the back case 53 is provided with a plug insertion hole 57 at the center portion, that is, at a position corresponding to the plug 41 attached to the plug mounting plate 26 of the reflective element 21.

Furthermore, a semicircular groove-like column mounting portion 58 is provided at the lower portion of the back case 53. The column attachment portion 58 is provided with

column attachment bases

59a and 59b with a predetermined interval in the vertical direction. The support bases 59a and 59b are provided with through holes along the central axis, and nuts are mounted in the through holes. The antenna column 62 attached to the column mounting portion 58 is provided with mounting holes (not shown) at positions corresponding to the

column mounting bases

59a and 59b in the upper end portion. The antenna column 62 has an upper end positioned on the column mounting portion 58, a screw is inserted into the mounting hole, screwed into a nut provided on the

column mounting bases

59 a and 59 b, and tightened to the column mounting unit 58. Fix it.
Further, a positioning base 63 is provided on the inner side of the column mounting portion 58 slightly above the column mounting base 59b. The positioning base 63 is provided at a position corresponding to the positioning projection 20 provided on the second reflecting element portion 22b of the reflecting element 21, and a positioning hole is provided at the upper end. The positioning projection 20 of the second reflecting element portion 22b is inserted into the positioning hole to position the antenna.

In the above configuration, when the antenna body 10 is stored in the resin case 51, first, the antenna body 10 is attached to the back case 53 as shown in FIG. At this time, the antenna body 10 performs positioning by inserting the positioning protrusion 20 provided on the second reflecting element portion 22b of the reflecting element 21 into the positioning hole provided on the positioning base portion 63 of the back case 53, and then performing positioning. The

screws

19a and 19b are inserted into the

holes

18a and 18b provided in the

antenna elements

12a and 12b of the radiating element 11, and are screwed into the screw holes of the attachment bases 55a and 55b provided in the rear case 53, and then fastened and fixed. To do. At this time, the plug 41 attached to the plug mounting plate 26 of the reflective element 21 is inserted into a plug insertion hole 57 provided in the back case 53.

Next, the front case 52 is positioned on the front side of the antenna body 10, a screw is inserted from the back side into the through hole of the front case mounting base 56 provided on the back case 53, and the tip thereof is provided on the front case 52 side. The front case 52 and the rear case 53 are fixed by screwing into the screw holes of the mounting base.

When the antenna is attached to the antenna support 62, the upper end of the antenna support 62 is positioned at the support attaching part 58 provided in the back case 53, and a screw is inserted into the attachment hole provided in the antenna support 62. Then, the resin case 51 is attached to the antenna support 62 together with the antenna body 10 by screwing and tightening to nuts provided on the

support bases

59a and 59b. By using the antenna support 62, the antenna can be attached to the outside of the house such as a veranda (see FIG. 8).

FIG. 6 shows the gain characteristics of the UHF band antenna according to the above embodiment. The horizontal axis represents frequency (MHz) and the vertical axis represents operation gain (dBd). The UHF band antenna according to the above embodiment can obtain a high gain of 6.2 to 8 dBd over the entire band of 470 to 77 MHz.

FIG. 7 shows the VSWR characteristics of the UHF band antenna according to the above embodiment. The horizontal axis represents frequency (MHz) and the vertical axis represents VSWR. The UHF band antenna according to the above embodiment can have a VSWR of “2” or less in a low frequency band of 470 to 630 MHz, and a VSWR of “2.4” or less even in a high frequency band of 630 to 770 MHz. It can be.

According to the above-described embodiment, the radiating element 11 is bent back at an angle of about 135 ° on both sides, and the reflecting element 21 is bent on the

side elements

23a and 23b on both sides and the

side elements

23a and 23b. By providing the holes 24a to 24d, the lateral width W5 of the antenna body 10 can be reduced to about 0.188λa, and can be reduced to ½ or less compared to 0.5λa which is the lateral width of the conventional antenna. As a result, the wind receiving area can be greatly reduced.
In addition, since the

windows

54a and 54b are provided in the resin case 51 and air can be passed between the front and back surfaces, the wind receiving area can be further reduced.

In the above embodiment, the

side elements

23a and 23b of the reflecting element 21 are provided with the square holes 24a to 24d. However, the shapes of the holes 24a to 24d are not limited to the square, You may form in a shape.
The dimensions of each part of the UHF band antenna are not limited to the values shown in the above embodiment, and can be set to arbitrary values according to the desired characteristics of the antenna.
Furthermore, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage.
This application is based on a Japanese patent application filed on April 20, 2010 (Japanese Patent Application No. 2010-097250) and a Japanese patent application filed on May 28, 2010 (Japanese Patent Application No. 2010-123424). Incorporated herein by reference.

INDUSTRIAL APPLICABILITY The present invention can provide a vertically long UHF band antenna suitable for terrestrial digital broadcast reception that can reduce the wind receiving area while ensuring a sufficient gain, and has industrial applicability. It is expensive.

Claims

In a UHF band antenna comprising an antenna body formed by opposingly reflecting reflective elements on the back surface of a radiating element, and a case housing the antenna body,
The radiating element includes a first antenna element and a second antenna element which are arranged with a predetermined interval in a vertical direction in the same plane by a plate-like conductive member, and the first antenna element and the second antenna element. A coupling line that couples to the antenna element; a feeding unit that is provided in a central portion of the coupling line and feeds power to the first antenna element and the second antenna element; and the first antenna element and the second antenna element. A first gap formed in the coupling line between at least one of the antenna elements of the antenna element and the feeding portion,
The reflecting element includes a reflecting element portion provided at a predetermined interval in the vertical direction, a side element provided with a predetermined width on both the left and right sides and bent backward by approximately 90 °, and the side elements. A vertically long hole formed in each of the upper portion and the lower portion, and a second gap portion formed at a position corresponding to the first gap portion provided in the radiation element,
The case for housing the antenna main body includes a window at a position corresponding to the first gap formed in the radiating element and the second gap formed in the reflective element. antenna.
The UHF band antenna according to claim 1 has a vertically long shape.