JPH0479503A - Planar antenna - Google Patents

Abstract

PURPOSE:To adopt punching of a metallic plate offering ease of manufacture and inexpensive manufacture cost for the manufacture of a radiation circuit board by forming a radiation element of the radiation circuit board with an aperture. CONSTITUTION:The antenna consists of a radiation circuit board 1 formed by punching plural apertures 2 being circular polarized radiation elements from a metallic plate such as aluminum at an equal interval longitudinally and laterally, a feeding circuit board 4 arranged under the radiation circuit board 1 at a prescribed interval and on which feeders of a feeding circuit coupled electromagnetically with each aperture 2 are formed by etching, and a ground conductor board 5 made of a metallic board such as an aluminum board on market arranged under the feeding circuit board 4 at a prescribed interval. Thus, the planar antenna is realized in which the cross polarized wave characteristic with a high efficiency over a wide band is easily and inexpensively ensured.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a planar antenna.

[Prior Art] Conventional planar antennas have been proposed in which one is constructed by bending a strip line into a crank shape, and the other is constructed by a plurality of patch elements.

However, these are narrow band 300-400MH for boat fishing.
It has been difficult to have sufficient performance over the entire broadcast band spanning z. Furthermore, the loss from the power supply line was large, making it difficult to improve efficiency.

Therefore, in order to achieve high efficiency and wideband, ground conductor board, power supply circuit board,
An I-ribrate type planar antenna consisting of a radiating circuit board was developed, and the reception performance was 1'lfs, which was comparable to that of a parabolic antenna.
We have reached a point where we have the following.

[Problems to be Solved by the Invention] However, although the above-mentioned planar antenna consisting of an annular slot-type radiating element has the same performance as a parabolic antenna, there is a cost problem due to the high cost of the etching process. Furthermore, it has been difficult to ensure cross-polarization characteristics over a wide band.

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a planar antenna that is highly efficient, easily ensures cross-polarization characteristics over a wide band, and can be manufactured at low cost. There is something to do.

[Means for Solving the Problems] To achieve the above object, the invention described in the claims] provides a planar antenna consisting of a ground conductor plate, a feeding circuit board, and a radiation circuit board, which is symmetrical on the left and right sides and , the bottom is also symmetrical to the left,
An outer circumferential shape in which two shapes that are symmetrical on the right and symmetrical on the bottom are stacked so that they are perpendicular to each other with a common center, with both ends of the other shape protruding outward from both sides of one shape. A plurality of apertures consisting of the following are formed on a radiating circuit board, and the apertures are electromagnetically coupled to the feed line of the feed circuit board located below the radiating circuit board.

The invention according to claim 2 is the invention according to claim 1,
The outer peripheral shape formed using two rectangles of different sizes is used as the shape of an aperture.

The invention according to claim 3 is the invention according to claim 1, in which a spacer having a space layer or a dielectric constant and a dielectric loss tangent close to the space layer is provided between the ground conductor plate and the feeding circuit board, and between the feeding circuit board and the radiation circuit board. It is something that has been mediated.

The invention according to claim 4 is the invention according to claim 3,
A foamed plastic sheet is used as the spacer.

The invention according to claim 5 is the invention according to claim 3,
As the spacer, a sheet formed by partially trapping air between extremely thin plastic films is used.

[Function] According to the present invention, since the radiating elements of the radiating circuit board are formed by apertures, the radiating circuit board can be manufactured by punching a metal plate, which is easy to manufacture and has low manufacturing costs. This makes it possible to significantly reduce costs compared to the conventional etching process, and by manufacturing the radiating circuit board by punching a metal plate, it is possible to obtain a radiating circuit board with excellent rigidity. It is possible to improve the accuracy of the spacing between the ground conductor board, the feeding circuit board, and the radiation circuit board, and to minimize variations in antenna performance.

Furthermore, the unevenness of the radiation circuit board can be improved, loss can be reduced, and an extremely highly efficient antenna can be obtained.

Moreover, since it is a radiating element using an aperture, the Q value becomes small, and it is effective in expanding the band.

Furthermore, over a shape that is symmetrical on the left and right and symmetrical on the top and bottom, another shape that is symmetrical on the left and right and symmetrical on the top and bottom are stacked so that they are perpendicular to each other with a common center. Since a large number of apertures are formed on the radiation circuit board, each of which has an outer circumferential shape with both ends protruding outward from the other end, the electromagnetic coupling between the feed line and the aperture alone can produce good circularly polarized waves. characteristics were obtained.

Furthermore, if the aperture was formed using a bipedal outer circumferential shape formed using two rectangles of different sizes, an antenna with the best circular polarization characteristics could be obtained.

Furthermore, by interposing a spacer having a space layer or a dielectric constant and dielectric loss tangent close to the space layer between the ground conductor plate and the feeding circuit board, and between the feeding circuit board and the radiation circuit board, an antenna with low dielectric loss can be realized. In particular, when a foamed plastic sheet is used as the spacer, the cost is low and it is easy to handle.Furthermore, it is possible to use a sheet formed by partially trapping air between ultra-thin plastic films as the spacer. When used, it is possible to realize an antenna that is cheaper and has less dielectric loss.

Examples] The present invention will be explained below with reference to Examples.

Figure 1 shows a partially omitted exploded perspective view of Embodiment 1, in which a circularly polarized radiating element is mounted on a metal plate such as aluminum with a thickness of 0.41 mm. A radiation circuit board 1 formed by punching out apertures 2 at equal intervals vertically and horizontally, and a power supply that is placed below the radiation circuit board 1 at a fixed interval and capable of electromagnetically coupling to each aperture 2. It consists of a power supply circuit board 4 on which a circuit power supply line is formed by etching, and a ground conductor plate 5 made of a metal plate such as a commercially available aluminum plate and placed below the power supply circuit board 4 at a certain distance. There is. FIG. 2 shows its cross-sectional configuration, and shows the space between the ground conductor plate 5 and the power supply circuit board 4, and the power supply circuit board 4.
A spacer 6 made of a foamed plastic sheet is interposed between the radiating circuit board 1 and the radiating circuit board 1.

The aperture 2 formed on the radiation circuit board 1 has a rectangular shape with a short side of 9 mm and a long side of 17.5 mm, and a rectangular shape with a short side of 9 mm and a long side of 13 mm.
The radiating circuit board 1 is punched in 16 rows and 16 columns at intervals of 20 mm in the embodiment.

The power supply circuit board 4 is a printed circuit board with a circuit pattern formed by etching, and when placed below the radiation circuit board 1, the coupling portion 3 of the power supply circuit corresponding to the aperture 2 and the aperture 2 are connected to each other. are electromagnetically coupled as shown in FIG. Here coupling part 3
It is desirable that the tip of the aperture 2 be located at a position protruding from the center of the aperture 2.

The ground conductor plate 5 is formed using a metal plate such as a commercially available aluminum plate having a thickness of 2 mm, for example.

The planar antenna of the example constructed as described above has a wide band of 11.5 to 1.2.2 GHz (70 GHz).
0 MHz), an efficiency of 65% or more and a cross-polarization characteristic of 20 dB or more were obtained.

Furthermore, compared to the conventional annular slot antenna, which is manufactured by etching a printed circuit board, the manufacturing cost of this embodiment, which is performed by punching, is about 30% lower.

Furthermore, it was confirmed that there was no deterioration in performance even in accelerated weathering tests, which were equivalent to when this antenna was used outdoors for about two years.

Himi ■yu The shape of the aperture 2 in the above Example 1 was the same shape as the outer circumferential shape created by combining rectangles, but as shown in FIG. In Example 2, a square with one side of 12 mm, a long side of 1.8 mm, and a short side of 1
A radiation circuit board 1 is formed by punching out a plurality of apertures 2 having the same shape as the outer circumferential shape when a rectangle of 0 mm and a rectangle having a common center and perpendicular to each other are punched into a metal plate in the same arrangement as in Example 1. An antenna performance similar to that of Example 1 was obtained.

Hinomi ■Yu In the first embodiment, the outer circumferential shape formed by the combination of rectangles was used as the shape of the aperture 2, and in the second embodiment, the outer circumferential shape formed by the combination of squares and rectangles was used as the shape of the aperture 2. As shown in FIG. 5, a radiating circuit board 1 is used in which an aperture 2 having the same shape as the outer circumference formed by orthogonally intersecting hexagons of different sizes is provided.

This third embodiment uses an aperture 2 having such a shape as 6
Cross polarization discrimination of 15 dB or more was obtained with an efficiency of 0% or more.

The shape of the aperture 2 is a combination of two types of shapes, such as a combination of a hexagon and a rectangle, a combination of rhombuses, or a combination of a rectangle and a rhombus, as shown in FIGS. 6(a) to (c). You may also use the outer peripheral shape made by
Alternatively, the outer peripheral shape may be a combination of shapes other than polygons, such as ellipses.

In each of the above embodiments, a dielectric made of a foamed plastic sheet was used as the spacer 6, but in this embodiment, as shown in FIG. 7, one film sheet is overlaid on another film sheet. An air cap sheet with a height of about 2 mm, in which a number of air-closed caps 6a are independently formed using another film sheet, is used as the spacer 6, and this spacer 6 is used to connect the radiation circuit board 1 and the feeding circuit board 1. and between the power supply circuit board 4 and the ground conductor board 5, as shown in FIG.

In this embodiment, it is cheaper than the embodiment using a foamed plastic sheet, and furthermore, since the dielectric material approaches the space layer, dielectric loss etc. can be improved.

Furthermore, in each of the above embodiments, a metal plate such as an aluminum plate is used as the radiation circuit board 1 and the aperture 2 is formed therein, but the aperture 2 is formed by etching using the silver foil part of a commercially available flexible printed circuit board as the conductive plate. Even when formed, antenna characteristics similar to those of the two-legged embodiment were obtained. Of course, in this case, the cost is slightly higher than that of punching.

[Effect of the invention] Since the invention as claimed in claim 1 forms the radiating element of the radiating circuit board with an aperture, the punching process of a metal plate, which is easy to manufacture and inexpensive to manufacture, is adopted for manufacturing the radiating circuit board. This makes it possible to significantly reduce costs compared to the conventional etching process.Furthermore, by manufacturing the radiating circuit board by punching a metal plate,
A radiating circuit board with excellent rigidity can be obtained, and as a result, it is possible to improve the accuracy of the spacing between the ground conductor board, the feeding circuit board, and the radiating circuit board, and to minimize variations in antenna characteristics. Furthermore, it is possible to improve the unevenness of the radiating circuit board, which reduces loss and provides an extremely highly efficient antenna.Also, since the radiating element is an aperture, the Q value is reduced and the band is expanded. It is also effective to create a shape that is symmetrical on the left and right, and symmetrical on the bottom, and another shape that is symmetrical on the left and right, and symmetrical on the top and bottom, so that they are orthogonal to each other with a common center. Since a large number of apertures are formed on the radiation circuit board, each having an outer peripheral shape in which both ends of one shape protrude outward from both sides of the other shape, an electromagnetic cup between the feed line and the aperture is formed. The ring alone has the effect of providing good circular polarization characteristics.

Furthermore, the invention as claimed in claim 2 has the effect that an antenna with the best circular polarization characteristics can be obtained by using two rectangles of different sizes and by shifting the shape of the outer periphery of the two legs from the shape of the aperture. be.

Furthermore, the invention according to claim 3 provides a dielectric material by interposing a spacer having a space layer or a dielectric constant and dielectric loss tangent close to those of the space layer between the ground conductor plate and the feeding circuit board, and between the feeding circuit board and the radiation circuit board. An antenna with low loss can be realized, and in particular, the invention according to claim 4 uses a foamed plastic sheet as the spacer, which has the effect of reducing cost and ease of handling.Furthermore, the invention according to claim 5 has the effect that the spacer can be Since a sheet formed by partially trapping air between ultra-thin plastic films is used, it is possible to realize an antenna that is inexpensive and has even less dielectric loss.

[Brief explanation of drawings]

FIG. 1 is a partially omitted exploded perspective view of Embodiment 1 of the present invention;
FIG. 2 is a partially omitted cross-sectional view of the same as above, FIG. 3 is an explanatory diagram of the electromagnetic coupling state between the aperture and the power supply line, and FIG. 4 is an explanatory diagram of the shape of the aperture according to the second embodiment of the present invention. , FIG. 5 is an explanatory diagram of the shape of the aperture according to the third embodiment of the present invention, FIG. FIG. 8 is a reduced sectional view of the spacer used, and a sectional view of the same part can be omitted. 1 is a radiation circuit board, 2 is an aperture, 3 is a coupling part, 4 is a power supply circuit board, is a coupling part, 5 is the ground conductor board. Agent Patent attorney Stone 1) Cho 7

Claims (5)

[Claims] (1) In a planar antenna consisting of a ground conductor board, a feeding circuit board, and a radiation circuit board, the left and right sides are symmetrical, and the top and bottom are also symmetrical.The left and right sides are symmetrical, and the top and bottom are also symmetrical. A large number of apertures are formed on the radiating circuit board, each having an outer circumferential shape in which shapes are stacked orthogonally to each other with a common center, and both ends of one shape protrude outward from both sides of the other shape. A planar antenna characterized by electromagnetically coupling a feed line of a feed circuit board located below a circuit board and an aperture. (2) The planar antenna according to claim 1, wherein the aperture has an outer peripheral shape formed using two rectangles of different sizes. (3) A spacer having a space layer or a dielectric constant and dielectric loss tangent close to that of the space layer is interposed between the ground conductor plate and the feed circuit board, and between the feed circuit board and the radiation circuit board. Planar antenna as described. (4) The planar antenna according to claim 3, wherein a foamed plastic sheet is used as the spacer. (5) The planar antenna according to claim 3, wherein the spacer is a sheet formed by partially trapping air between extremely thin plastic films.