JPH0583022A - Planar antenna - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To realize a planar antenna that facilitates the sealing work performed at the joint between the frame and radome. [Structure] A peripheral edge of the radome 5 is extended to an outer peripheral side at a joint portion between a circular frame 1 having an open upper portion and a radome 5 that forms a circular flat space inside by closing the opening surface of the frame 1. Then, a predetermined gap is provided at the joint. As a result, the sealing work performed at the joint between the frame 1 and the radome 5 becomes easy.

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a planar antenna suitable for use in the quasi-millimeter wave band such as satellite broadcasting and satellite communication.

[0002]

As is well known, various planar antennas have been put into practical use in recent years with the start of satellite broadcasting. In particular, in satellite broadcasting, miniaturization and higher performance of this planar antenna are advancing along with improvement of transmission power and improvement of noise figure (NF) of a BS converter connected to a receiving antenna.

Among the small planar antennas of this type, there is a radial line slot antenna using a radial waveguide with a small transmission loss. FIG. 3 is a perspective sectional view showing the structure of this radial line slot antenna. In this figure, reference numeral 1 is a frame constituting the back side of this antenna. The frame 1 is formed of a metal conductor, has a circular shape when viewed from the front, and has a flat container shape in which an upper portion is widely opened. A slot plate 2 is provided with a slot array formed by etching or the like on a metal disk. Reference numeral 3 is a low-foam dielectric material filled between the frame 1 and the slot plate 2. Here, the slot plate 2 and the frame 1 form a radial waveguide 4. When the permittivity of the low foam dielectric 3 interposed in the radial waveguide 4 is ε, the guide wavelength λg of the transmission wave in the radial waveguide 4 is the spatial wavelength λ of 1 / √.
It is shortened by ε. For this reason, this low foam dielectric 3 is called a slow wave circuit.

5 is a radome which covers the front of the antenna and seals the joint with the peripheral edge of the frame 1 with a silicone adhesive having excellent resistance to high and low temperatures in order to suit the outdoor use. Is. A space between the radome 5 and the slot plate 2 is filled with a high-foam spacer 6 having a dielectric constant substantially equal to that of air, whereby the slot plate 2 is brought into close contact with the low-foam dielectric 3 and
The electric performance is stabilized by keeping the distance from the frame 1 constant. Reference numeral 7 denotes a rubber ring for protecting the outer circumference which is provided so as to cover the joint between the frame 1 and the radome 5.
The outer peripheral protection rubber ring 7 protects the antenna from impacts during transportation or construction. Reference numeral 8 is a power supply unit, and 9 is a BS converter that converts the satellite broadcast waves supplied from this power supply unit to the UHF band.

Next, FIG. 4 is a sectional view showing an example of a joint portion between the frame 1 and the radome 5 described above. In this figure, the parts corresponding to those in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted. As shown in this figure, the peripheral edge of the frame 1 has a U-shape folded back with respect to the opening surface, and the edge of the radome 5 is located in this U-shaped bent portion. It is formed so as to be joined. As a result, the frame 1 and the radome 5 are in close contact with each other. Also,
FIG. 5 is a cross-sectional view showing another joining example. In this case, the peripheral edge of the frame 1 is bent inward with a predetermined curvature with respect to the opening surface, while the edge of the radome 5 is formed so as to come into contact with and overlap the outer edge of the radome 1. It is in close contact with the radome 5.

The joint between the frame 1 and the radome 5 having such a structure is sealed with a silicone adhesive as described above. This sealing operation is performed in the antenna assembly process using the jig shown in FIG. In this figure, 20 is a turntable, 2
1 is a presser foot. This presser foot 21 is a frame 1 arranged to face the radome 5 placed on the turntable 20.
Press. The air cylinder 22 applies a pressing force generated by the supplied compressed air to the pressing tool 21. D1, D
A dispenser D1 is filled with a silicone resin, and a dispenser D2 is filled with a hot-melt resin.

In order to seal the joint between the frame 1 and the radome 5 with such a jig, first, the antenna in the temporarily assembled state is arranged on the turntable 20, and
The pressing tool 21 presses this with a uniform pressure. Then, while rotating the turntable 20, the dispenser D is placed at a predetermined position of the joint between the frame 1 and the radome 5.
2 is used to inject the hot melt resin and temporarily fix it. Then, using the dispenser D1, the frame 1 and the radome 5
A silicon resin is injected over the entire circumference of the joint.
After these operations are completed, the assembly is completed by removing it from the jig, allowing it to stand for 24 hours to cure the resin, and mounting the outer peripheral protection rubber ring 7 after fixing the resin and fixing it with an adhesive. To do.

Since the silicone resin injected into the joint between the frame 1 and the radome 5 is highly elastic even when cured, it fulfills an adhesive function and is formed of the resin and the radome 5. It also plays a role of absorbing the expansion / contraction difference due to the difference in thermal expansion coefficient from the frame 1.

[0009]

The conventional radial line slot antenna described above has the configuration shown in FIG.
As shown in FIG. 6 and FIG. 6, since the edge of the radome 5 and the peripheral edge of the frame 1 are in close contact with each other, the injection needle (outer diameter 2 mmφ) of the dispenser D1 or D2 described above is inserted into this joint portion. As a result, it has been difficult to inject the silicone resin. That is, it is necessary to inject this silicone resin evenly over the entire circumference of the joint between the frame 1 and the radome 5, but in reality, only a small amount can be infused, so that the coating thickness of the resin can be increased. It depends on the place. Therefore, the expansion / contraction difference due to the difference in expansion coefficient between the dielectric plate radome 5 and the metal plate frame 1 cannot be absorbed, and in some cases the radome 5
There is a concern that cracks may occur in the frame and the frame 1 and the radome 5 may separate. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a planar antenna that facilitates the sealing work performed at the joint between the frame 1 and the radome 5.

[0010]

According to the present invention, there is provided a circular frame having an open upper portion, and a radome for closing the opening surface of the frame to form a circular flat space therein. A planar antenna having an outer peripheral ring attached to a joint with a radome is characterized in that a peripheral edge of the radome is projected to an outer peripheral side and a predetermined gap is provided at the joint. Also, in the gap,
While sealing the joint between the frame and the radome,
It is characterized by being filled with a silicon resin to be adhered.

[0011]

According to the present invention, the outer periphery of the radome is formed at the joint between the circular frame having an open upper portion and the radome that covers the opening surface of the frame and forms a circular flat space inside. A predetermined gap is provided at the joint by projecting to the side. As a result, the sealing work performed at the joint between the frame and the radome becomes easy. Further, since the gap is uniformly filled with silicon resin, the radome and the frame can be reliably bonded together, and the expansion / contraction difference due to the difference in the thermal expansion coefficient between the dielectric plate and the metal plate can be surely ensured. Can be absorbed.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. A. First Embodiment FIG. 1 is a sectional view showing the structure of a first embodiment according to the present invention. In this figure, parts corresponding to those in FIG. 4 are assigned the same reference numerals and explanations thereof are omitted. This structure is different from the structure shown in FIG. 4 in that the frame 1 and the radome 5 are
The point is that the structure is provided with a space SA into which the above-mentioned silicone resin is injected and a space SB into which the injection needle of the dispenser D1 is inserted at the time of this injection, at the joint portion with.

That is, on the peripheral edge of the frame 1, there is formed a curling portion C having an arcuate cross section having a predetermined radius of curvature from the opening surface. On the other hand, the peripheral edge of the radome 5 is formed so as to come into close contact with the curling portion C, and further, this edge is formed so as to project in the outer peripheral direction in order to provide the above-mentioned space SA. According to such a structure, the curling portion C positions the radome 5 and the frame 1, so that the radome 5 and the frame 1 can be easily joined. Further, at the time of the sealing work in the above-described assembly process, the space SB is provided so that the dispenser D1,
The injection needle of D2 can be inserted, and since the space SA is provided, the hot melt resin can be applied to a predetermined place at the time of temporary fixing, and the silicone resin serving as a sealing agent can be applied to this antenna. It can be injected so as to have a uniform coating film thickness over the entire circumference.

B. Second Embodiment Next, FIG. 2 is a sectional view showing the structure of the second embodiment according to the present invention. In this figure, parts corresponding to those in FIG. 5 are assigned the same reference numerals and explanations thereof are omitted. 5 is different from the structure shown in FIG. 5 in that a space SA into which the silicone resin is injected and a space SB into which the injection needle of the dispenser D1 is inserted at the joint between the frame 1 and the radome 5 are inserted. The cross-sectional structure is provided with.

That is, the curling portion C having a predetermined radius of curvature on the peripheral edge of the frame 1 and curved inward of the opening surface.
Are formed. On the other hand, the peripheral edge of the radome 5 is formed so as to come into close contact with the curling portion C, and further, this edge is formed so as to project in the outer peripheral direction in order to provide the above-mentioned space SA. According to such a structure, the curling portion C allows the radome 5 and the frame 1 to be
By locating and, the joining of these becomes easy. Moreover, at the time of sealing work, the space S
The injection needles of the dispensers D1 and D2 can be easily inserted into B, and since the space SA is provided, the hot melt resin can be applied to a predetermined place at the time of temporary fixing, and this antenna It becomes possible to inject the silicone resin with a uniform coating film thickness over the entire circumference.

[0016]

As described above, according to the present invention, the joint portion between the circular frame having an open upper portion and the radome which closes the opening surface of the frame and forms a circular flat space inside is formed. In addition, since the peripheral edge of the radome is projected to the outer peripheral side and a predetermined gap is provided in the joint portion, the sealing work performed at the joint portion between the frame and the radome can be easily performed. Also, in the gap,
Since the silicone resin is uniformly filled, the radome and the frame can be reliably bonded together, and the expansion and contraction difference due to the difference in the thermal expansion coefficient between the dielectric plate and the metal plate can be reliably absorbed.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a first embodiment according to the present invention.

FIG. 2 is a sectional view showing the structure of a second embodiment according to the present invention.

FIG. 3 is a perspective sectional view showing a structural example of a radial line slot antenna which is a conventional planar antenna.

FIG. 4 is a cross-sectional view for explaining a conventional example.

FIG. 5 is a sectional view for explaining a conventional example.

FIG. 6 is a diagram for explaining a conventional example.

[Explanation of symbols]

 1 ... Frame, 5 ... Radome, SA, SB ... Space.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masanori Suzuki 1-5-1, Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. (72) Inventor Tatsuhiro Okano 1-5-1, Taito, Taito-ku, Tokyo Toppan Imprint Co., Ltd.

Claims (2)

[Claims] 1. A circular frame having an upper opening, and a radome that covers the opening surface of the frame and forms a circular flat space inside, and an outer peripheral ring is formed at the joint between the frame and the radome. A planar antenna in which the radome is attached to the outer peripheral side of the radome, and a predetermined gap is provided at the joint. 2. The planar antenna according to claim 1, wherein the gap is filled with a silicone resin that seals and bonds the joint between the frame and the radome.