JP2650778B2 - Planar antenna - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circularly polarized planar antenna used as a receiving antenna for satellite broadcasting or the like.

[Prior Art] Conventionally, as a planar antenna for circularly polarized wave reception, a device using a patch element or an annular slot element obtained by printing or etching has been widely used as an antenna element. Although the planar antenna using the structure is easy to assemble, it has a disadvantage that the receiving efficiency is not always high.

On the other hand, a planar antenna with a structure in which the antenna elements are lifted from the reflecting surface has high reception efficiency, but it is necessary to mount 100 to 300 elements together with their supports individually on the metal plate surface as the reflecting surface. Therefore, there is a disadvantage that workability is poor and assembly is difficult.

FIGS. 5A and 5B show the mounting structure of an antenna element in a conventional planar antenna, respectively. FIG. 5A shows a case of a helical element, and FIG. 5B shows a case of a patch element. ing.

That is, an element support hole 12 is formed in the conductor plate 11 serving as a reception reflection surface of satellite radio waves, and a support 13 made of a dielectric is fitted into the support hole 12. Then, a small hole 14 is formed at the center of the support 13, and the shaft portion 15 of the helical antenna element 15 or the patch antenna element 16 is formed in the small hole 14.
Insert a or 16a. Thus, the helical antenna element 15 or the patch antenna element 16 is fixed to the conductor plate 11.

[Problems to be Solved by the Invention] However, when the antenna element is fixed to the conductor plate by the above structure, for example, when the helical antenna element 15 is used, the conductor plate 11 having a diameter of about 30 cm Since the number of element support holes 12 is required, the same number of dielectric supports 13 need to be manufactured, and mounting work by combination with the helical antenna element 15 is required, which increases the manufacturing cost and hinders cost reduction. .

The present invention has been made in view of the above problems, and even when a high receiving efficiency is obtained by using a structure in which an antenna element is floated above a reflecting surface, production and assembly work are not troublesome.
An object of the present invention is to provide a planar antenna that can be reduced in cost.

[Means for Solving the Problems] That is, a planar antenna according to the present invention is provided inside a metal case having a one-sided opening, a dielectric having a large number of projections formed on a surface thereof, and a surface of the dielectric. A conductor plate having a plurality of holes that are superimposed thereon and into which a plurality of protrusions of the dielectric are respectively inserted, and standing on the upper end surface of each of the protrusions of the dielectric inserted through the plurality of holes of the conductor plate. An antenna element to be provided, an annular short-circuit portion for electrically connecting the outer peripheral edge of the metal case and the outer peripheral edge of the conductor plate, and the dielectric member provided on the non-opening surface side of the metal case. And a converter having a power supply pin inserted at the center.

[Operation] In other words, it is not necessary to manufacture a dielectric support for each of the antenna elements and to incorporate the support into the conductor plate.
After the superposition of the first dielectric and the conductor plate on the metal case, only the antenna elements need to be erected, so that the assembly is easy and the production and operation costs can be reduced.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an assembling structure of a planar antenna. In FIG. 1, reference numeral 21 denotes a disk-shaped metal case, and a first metal case 21 having substantially the same diameter as the metal case 21 is provided on the surface of the metal case 21. The dielectric 22 is placed. The first dielectric 22 is made of a dielectric material having a low dielectric constant and a low loss, such as foamed polyethylene, and the surface of the dielectric 22 has 168 element supports when its diameter is 30 cm, for example. Are formed at predetermined intervals, and a conductor plate 24 is further placed on the surface of the dielectric 22. As shown by a broken line a, the conductor plate 24 has the first
A number of holes 25,... Corresponding to the respective protrusions 23,... Of the dielectric 22 are formed by press working. Are mounted on the surface of the first dielectric 22 with fitting. Here, the metal case 21 and the conductive plate 24 are electrically short-circuited by an annular short-circuit portion 27 surrounding the outer peripheral edge thereof.

Then, on the surface of the conductor plate 24, the large number of holes 25,
Are projected through the shaft portions 26a,... Of the helical antenna elements 26,. It is erected.

When a large number of helical antenna elements 26,... Are erected on the surface of the conductor plate 24 in a floating state, the second dielectric 28 is placed on the conductor plate 24. The second dielectric body 28 has a plurality of cylindrical holes 29 corresponding to the standing positions of the helical antenna elements 26,.
Are formed in the holes 29,..., As shown by broken lines c, the winding portions of the helical antenna element 26 are accommodated in the holes 29,. ,
Are fitted to each other and placed and superimposed on the conductor plate 24. Here, a cover 30 is provided further outside the second dielectric body 28.

On the other hand, a power supply hole 31 is formed in the center of the metal case 21, and a converter 32 is provided on the lower surface thereof. The power supply pin 32 a of the converter 32 is inserted into the center of the lower surface of the first dielectric 22. Then, a received signal is derived. The received signal frequency-converted through the converter 32 is a cable
Supplied to the receiver through 33.

FIG. 2 is a plan view of the metal plate 21 of the above-mentioned planar antenna and a conductor plate.
The cross-sectional configuration of the antenna body up to 24 is shown, the arrangement interval of the helical antenna elements 26,... Is set to one wavelength (λ) or less, and the hole diameter of the holes 25,. Is done. The distance between the metal case 21 and the conductor plate 24 is 1 /
At two wavelengths, the distance between the peripheral short-circuit portion 27 of the metal case 21 and the outer peripheral helical antenna element 26 is set to / 4 wavelength.

Here, assuming that the reception frequency of satellite broadcasting is 11.7 to 12 GHz, the diameter of the antenna main body is 30 cm, the number of helical antenna elements 26 is 168, the element wire diameter is 0.5 mm, the helical pitch is 1.8 mm, and the number of windings is 2 The winding diameter is 8 mm, the height from the conductor plate 24 to the helical start position is 1 mm, the length of the shaft 26a at the center of the antenna is 2 mm, and the shaft 26 at the outer periphery of the antenna.
If the length of a is set to 7.5 mm, a gain of about 31 dB can be obtained.

In this case, the reception signal transmitted from the helical antenna elements 26 to the power supply pin 32a through the first dielectric 22 in the metal case 21 becomes a traveling wave.

3 (A) and 3 (B) show the mounting structure of the antenna element in the planar antenna, respectively. FIG. 3 (A) shows the case of a helical element, and FIG. 3 (B) shows the case of a patch element. I have. In this case, the shaft of the helical element 26
26a or the shaft portion 34a of the patch element 34 is the first dielectric
Are inserted and erected into through holes 23a formed along the centers of the projections 23,.

Therefore, according to the planar antenna having the above configuration, the projecting portions 23,... For supporting the elements are formed in advance on the surface of the first dielectric 22, corresponding to the positions of the helical antenna elements 26,. After mounting the conductor plate 24 on which the plurality of holes 25,... Into which the convex portions 23 are inserted, the shaft portions of the helical antenna elements 26,. 26a,... Were inserted to form the antenna main body, so that a dielectric support 13 was manufactured corresponding to each of the antenna elements as shown in the conventional example in FIG. After the superposition of the first dielectric 22 and the conductor plate 24 on the metal case 21 without the necessity of assembling, only the helical antenna elements 26,... Work costs can be reduced.

The upper part of the antenna main body is provided with a second dielectric 8.
And further covered by the cover 30, it is possible to obtain a highly efficient and stable receiving characteristic even when the device is installed in a place where the environment is bad due to wind and snow.

Note that, as the first dielectric 22 in the above embodiment, a copper foil or the like is adhered to the surface of the first dielectric 22, and holes 25,... 24 can be realized.

In the above embodiment, the first dielectric 22 is superimposed without leaving a space between the metal case 21 and the conductor plate 24. For example, the first dielectric 22 has a convex portion 2 corresponding to the position where the antenna element is disposed.
3, and the surroundings are raised to the required height, and the dielectric in the other areas is formed thin so that the metal case 21 and the conductor plate 24 are formed.
And a space may be left between them.

FIGS. 4 (A) and 4 (B) show a plane configuration of a first dielectric 35 as another embodiment of the above-mentioned planar antenna and a cross-sectional configuration thereof along the line AA, respectively.
The dielectric 35 has a convex portion 2 corresponding to the arrangement position of the antenna element.
3, and the supporting columns of the conductor plate 24 only at the peripheral and outer peripheral portions
, Or as a support wall 37, and the other area is formed as a thin plate portion. A power supply pin insertion hole 39 into which the power supply pin 32a of the converter 32 is inserted is formed at the center of the dielectric 35. In this case, the support columns 36 of the dielectric 35 may be formed in a prism shape or the like in addition to the column shape.

That is, by using the first dielectric 35 having the above configuration, high-frequency loss in the dielectric is minimized,
Even better reception characteristics can be obtained.

Further, the antenna element in the above embodiment is configured using a helical antenna element or a patch antenna element, but may be configured using, for example, a spiral antenna.

[Effects of the Invention] As described above, according to the present invention, a dielectric is provided inside a metal case having a one-sided opening and a large number of protrusions are formed on the surface thereof, and the dielectric is polymerized on the surface of the dielectric A conductor plate having a plurality of holes into which a plurality of projections of the dielectric are respectively inserted, and an antenna standing on the upper end surface of each of the projections of the dielectric inserted through the plurality of holes of the conductor plate An element, an annular short-circuit portion for electrically connecting an outer peripheral edge of the metal case to an outer peripheral edge of the conductor plate, and a central portion of the dielectric provided on a non-opening surface side of the metal case. Therefore, even when the antenna element has a structure floating above the reflection surface (conductor plate) to obtain high reception efficiency, the production and assembly work does not require much labor. Planar Ann that enables low cost Can provide tena.

[Brief description of the drawings]

FIG. 1 is a diagram showing an assembly configuration of a planar antenna according to an embodiment of the present invention, FIG. 2 is a diagram showing a cross-sectional configuration of an antenna main body from a metal case to a conductor plate of the planar antenna, and FIG. FIGS. 4A and 4B are cross-sectional views each showing a mounting structure of an antenna element in the planar antenna, and FIGS. 4A and 4B are diagrams of a first dielectric material as another embodiment of the planar antenna. Planar structure and its A-
5 (A) and 5 (B) are cross-sectional views each showing a mounting structure of an antenna element in a conventional planar antenna. 21 ... metal case, 22, 35 ... first dielectric, 23 ... dielectric protrusion, 24 ... conductor plate, 25 ... conductor plate hole, 26 ...
Helical antenna element, 26a ... Shaft of helical element, 2
7 short circuit portion, 28 second dielectric, 29 helical element receiving hole, 30 cover, 31 power supply hole, 32 converter, 32a power supply pin, 33 cable , 34 ... Patch antenna element, 34a ... Shaft part of patch element, 36 ...
Dielectric support pillar, 37: Dielectric support wall, 38: Dielectric thin plate part, 39: Feeding pin insertion hole.

Claims (3)

(57) [Claims] 1. A dielectric which is installed inside a metal case having a one-sided opening and on which a number of projections are integrally formed, and which is superposed on the surface of the dielectric and is integrally formed on the surface of the dielectric. A conductive plate having a plurality of holes into which the formed plurality of protrusions are respectively inserted; and an antenna element standing upright on an upper end surface of each of the dielectric protrusions inserted through the plurality of holes of the conductor plate. An annular short-circuit portion that electrically connects the outer peripheral edge of the metal case and the outer peripheral edge of the conductor plate; and an annular short-circuit portion provided on the non-opening surface side of the metal case and inserted into the center of the dielectric. And a converter having a feed pin. 2. The planar antenna according to claim 1, wherein said conductor plate is made of a conductive foil film attached to a surface of said dielectric. 3. The dielectric body according to claim 1, wherein only the outer peripheral edge, a large number of projections, and the periphery of the projections are formed upright corresponding to the conductor plate, and the other region is formed in a thin plate shape. The planar antenna according to claim 1, wherein: