JPH0456503A - Planar antenna - Google Patents

Abstract

PURPOSE:To reduce the cost and to decrease the loss through the considering a dielectric body to be almost an air layer by forming the dielectric layer with an air cap sheet provided with lots of independent air caps. CONSTITUTION:A spacer 6 being a dielectric layer is provided between a ground conductor board 5 and a feeder circuit board 4 and between the feeder circuit board 4 and a radiation circuit board 1 to keep the interval of them. The spacer 6 is made of an air cap sheet in which another film sheet is overlapped on one film sheet and the other film sheet forms lots of caps 6a enclosing air independently. Thus, the space between the ground conductor board 5 and the feeder circuit board 4 and between the feeder circuit board 4 and the radiation circuit board 1 is kept by using the dielectric layer made of the inexpensive air cap sheet and since the dielectric constant is almost regarded to be that of an air layer, the loss is reduced.

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 batch elements.

However, these are narrow band for boat fishing of 300 to 400M.
It has been difficult to provide sufficient performance over the entire broadcast band spanning Hz.

Furthermore, the loss from the power supply line is large, making it difficult to improve efficiency.

Therefore, as shown in FIG. 9, in order to achieve high efficiency and wideband, a ground conductor plate 5 made of a commercially available aluminum plate, and a power supply circuit board 4 in which a power supply circuit is formed by etching the circuit board.
A triplate type planar antenna consisting of a radiating circuit board 1 in which an aperture 2 is punched out as a radiating element in an aluminum plate has been developed, and has achieved reception performance comparable to that of a parabolic antenna.

[Problems to be Solved by the Invention] However, in the conventional triplate type planar antenna, foamed plastic sheets are provided between the ground conductor plate 5 and the feeder circuit board 4 and between the feeder circuit board 4 and the radiation circuit board 1, respectively. However, when viewed as a dielectric material, there was a problem that the loss was greater than that of air, and the cost was also high.

The present invention has been made in view of the above-mentioned drawbacks, and its purpose is to provide a triplate type planar antenna between the ground conductor plate and the feeding circuit board, and between the feeding circuit board and the radiation circuit board. An object of the present invention is to provide a planar antenna in which the distance between the antenna and the antenna is maintained by a dielectric layer made of an air cap sheet that is inexpensive and has little loss.

[Means for Solving the Problems] In order to achieve the above-mentioned objects, the present invention provides a ground conductor plate made of a metal plate, a feed circuit board forming a feed circuit, and a metal plate formed by punching out an aperture of a radiating element. In a planar antenna, radiating circuit boards are stacked one on top of the other, separated by a predetermined distance from each other by a dielectric layer made of air bubbles and a synthetic resin. It consists of a cap sheet.

[Function] In the present invention, since the dielectric layer is formed of an air cap sheet, the cost is low, and when viewed as a dielectric, it can be regarded as an air layer, reducing loss.

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

Figure 1 shows a partially omitted exploded perspective view of Example 1. In this example, a circularly polarized radiation element is mounted on a metal plate such as 0.4-part aluminum. A radiation circuit board 1 is formed by punching out a plurality of barrel apertures 2 at equal intervals vertically and horizontally, and a power supply is placed below the radiation circuit board 1 at a fixed interval and capable of electromagnetically coupling to each aperture 2. A power supply circuit board 4 on which a power supply line 4a of the circuit is formed by etching, 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; A spacer 6, which is a dielectric layer, is interposed between the conductor plate 5 and the feeder circuit board 4 and between the feeder circuit board 4 and the radiation circuit board 1 to maintain the spacing between them.
It is made up of.

As shown in FIG. 2, the spacer 6 is made by stacking another film sheet on top of one film sheet, and forming a number of air-closed caps 6a independently with this other film sheet. It consists of a cap sheet, and is interposed between the ground conductor plate 5 and the feeder circuit board 4 and between the feeder circuit board 4 and the radiation circuit board 1, respectively, as shown in FIG.

As shown in FIG. 4, the aperture 2 formed on the radiation circuit board 1 has a square shape with one side having a dimension a (in the example, a=13 mm), the long side of which is approximately Ja, and the short side of which is approximately Ja. It consists of a hole with the same shape as the outer circumferential shape that is created when the squares are overlapped at a 45-degree angle to the horizontal axis passing through the center of the square, as shown in Figure 5, with the same center as the rectangle a / h, and the radial In this embodiment, the circuit board 1 is punched out in 16 rows and 16 columns at intervals of 20 mm. In other words, the aperture 2 is punched out in the form of a square hole with notches communicating outwardly from the edges of a pair of diagonal portions of the square hole.

When the feeder circuit board 4 is placed below the radiation circuit board 1, the feeder line 4a of the feeder circuit corresponding to the aperture 2
The coupling portion of the aperture 2 is electromagnetically coupled to the aperture 2 via a spacer 6 as shown in FIG. Here, it is preferable that the tip of the coupling portion be placed 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.

In the above example, the gain as a planar antenna was improved by 0.7 dB compared to the conventional antenna, and it was confirmed that the antenna was effective in improving characteristics.

In the above embodiment, the cap 6a of the air cap sheet constituting the spacer 6 inserted between the power supply circuit board 4 and the ground conductor plate 5 is oriented upward, but as shown in FIG. By arranging the spacer 6 made of an air cap sheet so that the upper and lower surfaces are sandwiched between the smooth surfaces of the air cap sheet, the smoothness of the feeding circuit board 4 is improved, and the antenna performance can be improved and stability can be maintained for a long time. become.

The shape of the aperture 2 may be a linear polarization type, such as a square with each side of 14 mm or a circle, as shown in FIGS. 7(a) and 7(b).

Practically speaking, the thickness of the aperture 2 is preferably about 0.1 to 2.0 mm; outside this range, punching becomes difficult.
This leads to increased costs.

[Effects of the Invention] The present invention provides a ground conductor plate made of a metal plate, a feed circuit board on which a feed circuit is formed, and a radiation circuit board made of a metal plate formed by punching out an aperture of a radiating element, each of which is made of air bubbles and synthetic resin. In a planar antenna in which dielectric layers are stacked and separated by a predetermined distance, the dielectric layer is composed of an air cap sheet with a number of independently formed caps for sealing air on the surface, so that rigidity can be improved. The spacing between the ground conductor board and the feeder circuit board, and between the feeder circuit board and the radiation circuit board, can be sufficiently maintained with a dielectric layer made of an inexpensive air cap sheet, and when viewed as a dielectric, it is This has the effect of reducing loss by treating it as an air layer.

[Brief explanation of the drawing]

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 air cap sheet that can be used in the same as above, Fig. 3 is a partially omitted cross-sectional view of the same as above, and Fig.
5 is an explanatory diagram of the shape of the aperture same as above, FIG. 6 is an explanatory diagram of the arrangement relationship between the aperture same as the above and the radiating element, FIG. 8 is a partially omitted sectional view of another embodiment of the present invention;
The figure is a partially omitted cross-sectional view of a conventional example. 1 is a radiation circuit board, 2 is an aperture, 3 is a patch element, 4
4 is a power supply circuit board, 4a is a power supply line, 5 is a ground conductor plate, 6 is a spacer, and 6a is a cap. Agent Patent Attorney Ishi 1) Chief 7 Figure 2/I power supply circuit &'8υX Figure 4 Figure 5 Figure 6 Figure 7 (b) Figure 8 Figure 9

Claims (1)

[Claims] (1) A ground conductor plate made of a metal plate, a feed circuit board with a feed circuit formed thereon, a radiation circuit board made of a metal plate formed by punching out the aperture of the radiating element, and a dielectric layer made of air bubbles and synthetic resin. 1. A planar antenna in which the dielectric layer is formed of an air cap sheet having a plurality of independently formed caps for sealing air on the surface thereof, in which the dielectric layer is arranged one on top of the other and separated by a predetermined distance.