JPH05152810A - Loop slot feeding antenna - Google Patents

Abstract

PURPOSE:To obtain the loop slot feeding antenna in which feeding by a waveguide is especially attained as the characteristic with respect to the circular slot antenna employed for a communication antenna or a broadcast antenna. CONSTITUTION:In the circular slot antenna which consists of a radiation disk 1 to which lots of power radiation slots 1a are made, a bottom plate disk 2 nearly of the same size as that of the radiation disk 1, and a fixing means 3 coupling mutually the radiation disk 1 and the bottom disk 2, and a waveguide space S is formed, a feeding loop slot 2a is formed in the middle of the bottom plate 2, and a waveguide formed with the loop slot having the same size as that of the feeding loop slot 2a is connected to be bonded with both the loop slots, then power is supplied to the waveguide space of the circular slot antenna as its feature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circular slot antenna used as a communication antenna or a broadcasting antenna, and more particularly to a loop slot feed type antenna characterized in that it can be fed by a waveguide.

[0002]

2. Description of the Related Art A conventional circular slot antenna is shown in FIG. 8 or 9, and in the example shown in FIG. 8, a circular radiation plate having a large number of slots 11a for generating circularly polarized waves. 11, a circular bottom plate 12 having a diameter substantially the same as that of the circular radiation plate 11, and a side wall plate 13 made of a radio wave absorber that connects the respective peripheral portions of the circular radiation plate 11 and the circular bottom plate 12 to each other.
And a waveguide space S is formed inside.

The example shown in FIG. 9 is a two-layer circular slot antenna in which the waveguide space S is divided into upper and lower two layers S1 and S2 by a circular intermediate plate 14. In these waveguide spaces, a dielectric is provided as a spacing member or a wave retarding means, if necessary.

In these circular slot antennas, a feeding opening 12a is provided at the center of a circular bottom plate 12, a coaxial line 15 as a feeding means is arranged in the feeding opening 12a, and an outer conductor 15b thereof is The inner conductor 15a is connected to the circular bottom plate 12 so as to project into the waveguide space S.

In such a coaxial line 15, a TEM mode having an electric field direction indicated by an arrow A in FIGS.
When electric power is supplied from the coaxial line 15 through the feeding opening 12a, the TEM mode of the coaxial line having the electric field direction indicated by the arrow B is converted into a TEM mode by 90 ° in the waveguide space S. Is excited, and the power supply is the power supply opening.
Propagating concentrically around 12a. Then, at that time, circularly polarized waves are generated from the circular radiation plate 11 having a large number of slots 11a formed therein.

Incidentally, reference numeral 16 in the drawing indicates a matching means arranged in the waveguide space, and reference numeral 17 indicates a radio wave absorber.

[0007]

By the way, in the conventional circular slot antenna as described above, it is not possible to feed power by the waveguide, and the circular bottom plate is provided with a power feeding opening for connecting to the power feeding means. Since it is necessary, processing is difficult depending on the material used for the circular bottom plate, and it is also difficult to maintain the airtightness of the antenna.

Further, when the dielectric is arranged inside the waveguide space, the inner conductor of the coaxial line projects into the waveguide space, and therefore it is necessary to form a hole or the like for passing the inner conductor through the dielectric. there were.

The present invention is intended to solve such a problem, and enables power supply by a waveguide by supplying power from a power supply means through a loop slot formed in a bottom plate. At the same time, it is an object of the present invention to provide a loop slot feed type antenna having a high airtightness and a simple structure.

[0010]

In order to achieve the above object, a loop slot feed type antenna according to claim 1 of the present invention comprises a circular radiation plate having a large number of power radiation slots formed therein. A circular slot antenna having a circular bottom plate having substantially the same size as that of the radiation plate and fixing means for coupling the radiation plate and the bottom plate to each other. A power feeding loop slot is formed, a power feeding means is provided to be coupled with the loop slot to supply power to the waveguide space, and the power feeding means is configured as a waveguide having a power feeding opening, Power is supplied to the waveguide space of the circular slot antenna by joining the feeding slot to the loop slot.

Further, the loop slot feed type antenna according to the second aspect of the present invention is characterized in that the matching means is arranged inside the waveguide space.

[0012]

In the above-described loop slot feed type antenna of the present invention, the feed loop slot formed on the bottom plate supplies electric power into the waveguide space through the feed loop slot, so that the waveguide space is operated in the TEM mode. Acts to excite.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A loop slot feed type antenna as an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cutaway perspective view, and FIG.
(a), (b), (C) are explanatory views of the slot pattern formed on the radiation plate, FIG. 3 (a) is a perspective view of the loop slot formed on the bottom plate, and FIG. 3 (b) is a waveguide. 4 is an enlarged view of the loop slot formed in FIG. 4, FIG. 4 is a perspective view of the waveguide, FIGS. 5 (a) and 5 (b) are perspective views of the loop slot portion of the waveguide, and FIGS. 7 (C) is a cross-sectional view of the power feeding portion, and FIGS. 7 (a) and 7 (b) are cross-sectional views of the main portion of the power feeding portion including the matching means.

As shown in FIG. 1, the loop slot feed type antenna according to the present embodiment has a circular radiation plate 1 and a bottom plate 2 which are substantially the same size and are arranged so as to be spaced apart from each other and to face each other. The radiation plate 1 is composed of a plate 1 and a bottom plate 2 and side wall plates 3 as fixing means arranged so as to be coupled to each other.
A circular waveguide space S is formed (inside thereof) surrounded by the bottom plate 2 and the side wall plate 3. In this waveguide space S,
If necessary, a dielectric 5 as a spacing member or a wave delaying means is provided. Further, without using the side wall plate 3, the dielectric 5 is used as a fixing means for the radiation plate 1 and the bottom plate 2,
It is also possible to combine the radiation plate 1 and the bottom plate 2.

A plurality of slots 1a are formed in the radiation plate 1 as openings for radiating power. As the slots formed in the radiation plate 1, as shown in FIG.
Slot pairs 1b, which are paired at an angle of approximately 90 ° to each other,
1c arranged on the spiral R, as shown in FIG. 2 (b),
Slots 1d and 1e arranged along two sets of spirals R ₁ and R ₂ , and as shown in FIG. 2 (c), slots 1f, 1g and 1h are arranged on three sets of spirals (not shown). For example, circularly polarized waves are effectively radiated from the radiation plate 1 in which these slots are formed. The length, the arrangement angle, and the arrangement interval of the slots are set so that desired power is radiated.

On the other hand, in the substantially central portion of the bottom plate 2, as shown in FIG.
The loop slot 2a as shown in FIG. 3 is formed, and this loop slot 2a acts as a power feeding opening.

A waveguide 4 (see FIG. 4) is arranged as a power feeding means, and a loop slot 4a as a power feeding opening formed in the upper surface of the waveguide and a loop slot 2a formed in the bottom plate 2 are provided. By joining them so that they coincide with each other, electric power is supplied from the waveguide 4 into the circular waveguide space S through both loop slots 2a and 4a.

The waveguide 4 is excited in the TE ₁ , ₀ mode having a current distribution as shown by the solid line i in FIG. 4, but it is radiated from the loop slot 4a formed on the upper surface of the waveguide and guided. The electric power supplied into the wave space S is the loop slot 2a.
6A, in the waveguide space S, it is excited in a TEM mode having an electric field direction indicated by an arrow B in FIG. 6A and propagates concentrically around the loop slot 2a. At this time, the bottom plate 2
The power supplied near the loop slot 2a formed in Fig. 3 has an electric field E direction indicated by a solid line and a magnetic field H direction indicated by a dotted line in Fig. 3B.

Further, the power feeding opening formed in the waveguide 4 may be a circular opening 4b as shown in FIG.
Even if the cross slot 4c is formed as shown in (b), the power supplied into the circular waveguide space S through the loop slot 2a formed in the bottom plate 2 propagates concentrically in the TEM mode.

The radiation plate 1, the bottom plate 2 and the waveguide 4 are made of metal, and the slot 1a, the loop slot 2a, and the power supply opening formed in the waveguide 4 are formed by etching or the like. For example, as one example thereof, it is formed by attaching a metal foil to a synthetic resin film and then performing etching processing. In this way, the upper surfaces of the radiation plate 1, the bottom plate 2 and the waveguide 4 are formed on the metal foil. In the case of a synthetic resin film attached with, the feeding openings formed in the slot 1a, the loop slot 2a, and the waveguide 4 are formed only in the metal foil, so that there is no hole in the film.

When the power feeding opening formed in the waveguide 4 is the loop slot 4a or the circular opening 4b, the surface of the waveguide 4 on which the power feeding opening is formed and the bottom plate 2 are formed as one sheet. It is also possible to share the metal and configure it integrally.

In the loop slot feed type antenna constructed as above, the loop slot 2a, 4
The electric power supplied to the waveguide space S via a
The light propagates in the TEM mode in a concentric manner from the center to the end of the inside, and circularly polarized waves are generated from the slot 1a formed on the radiation plate 1.

FIG. 6 (c) shows a modification of the above-mentioned one, and this modification is different from the above-mentioned one in that the waveguide 4 is provided with the matching means 6a. In such a configuration, the excitation mode is stable, and the waveguide 4 as the power feeding means and the waveguide space S can be matched,
The power supply can be effectively extracted and effective power supply can be performed.

Further, FIG. 6 (c) shows the dielectric 5 inside the waveguide space S.
It is also an example filled with.

With the above arrangement, this embodiment has the following advantages.

By supplying electric power from the electric power feeding means through the electric power feeding loop slot formed in the bottom plate, it becomes possible to feed electric power by the waveguide which has been impossible in the past.

When the bottom plate is made of a synthetic resin film to which a metal foil is adhered, a loop slot is formed only in the metal foil and no holes are formed in the film. The airtightness can be easily maintained and the weather resistance can be improved as compared with the bottom plate in which the hole as the power feeding opening is formed.

Further, since the loop slot formed in the bottom plate is formed by etching, it is not necessary to form a hole as a power supply opening, which is difficult depending on the material of the bottom plate, and the bottom plate can be easily formed. Not only that, since the internal conductor of the coaxial line does not project into the waveguide space, which was indispensable for conventional coaxial line power feeding, there is no need to process the dielectric material placed in the waveguide space. Since the structure is easy to manufacture, an inexpensive loop slot feed type antenna can be supplied.

As the matching means, as shown in FIGS. 7 (a) and 7 (b), the matching means 8 may be arranged on the circular bottom plate 2 in the loop slot 2a (see FIG. 7 (a)). Alternatively, it may be arranged at the center of the radiation plate 1 (see FIG. 7B).

In such a structure, the vicinity of the power feeding portion in the waveguide space S is matched, and the power fed is effectively propagated in the waveguide space S, so that effective transmission is possible.

[0032]

As described in detail above, in the loop slot feed type antenna of the present invention, the feed plate loop slot is formed in the bottom plate constituting the antenna, and the feed slot is provided in the waveguide space through the feed means. Since electric power is supplied, it is possible to supply electric power using a waveguide, which has been impossible in the past.

When the bottom plate is made of a synthetic resin film to which a metal foil is adhered, a loop slot is formed only in the metal foil and no holes are formed in the film. The airtightness can be easily maintained and the weather resistance can be improved as compared with the bottom plate in which a hole serving as a power supply opening for connecting with is formed.

Further, when the loop slot formed on the bottom plate is formed by etching, it is not necessary to form a hole as a power supply opening, which is difficult depending on the material of the bottom plate, and the bottom plate can be easily formed. Alternatively, it is possible to supply an inexpensive circular slot antenna because processing in the waveguide space, which is indispensable for the conventional power feeding by the coaxial line, is unnecessary, and the manufacturing is easy with a simple structure. Further, when the matching means is arranged in the waveguide space, the power to be fed is effectively propagated, so that the power is effectively fed and the efficiency of the antenna is improved.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a loop slot feed type antenna as an embodiment of the present invention.

2 (a), (b) and (C) are explanatory views of slot patterns formed on the radiation plate. FIG.

FIG. 3A is a perspective view of a loop slot formed in the bottom plate. (b) is an enlarged view of a loop slot formed in the waveguide.

FIG. 4 is a perspective view of a waveguide as the power feeding means.

5A and 5B are perspective views of a loop slot portion of the waveguide.

6 (a), (b), and (C) are cross-sectional views of the power feeding section.

7 (a) and 7 (b) are cross-sectional views of a main part of a power feeding unit including the matching means.

[Figure 8],

FIG. 9 is a partially cutaway perspective view of a conventional circular slot antenna.

[Explanation of symbols]

 1 radiation plate 1a slot 2 bottom plate 2a, 4a loop slot 3 side wall plate 4 waveguide 6a, 8 matching means

[Procedure amendment]

[Submission date] October 7, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 8]

[Figure 9]

Claims (2)

[Claims] 1. A circular radiation plate having a large number of power radiation slots formed therein, and a circular bottom plate having substantially the same size as the radiation plate.
In a circular slot antenna including a radiation plate and a fixing means for coupling the bottom plate to each other and having a waveguide space formed therein, a feeding loop slot is formed at the center of the bottom plate and coupled with the loop slot. Then, a power supply means for supplying power to the waveguide space is disposed, and the power supply means is configured as a waveguide having a power supply opening,
A loop slot feed type antenna, characterized in that power is supplied to a waveguide space of the circular slot antenna by joining the feed opening to the loop slot. 2. The loop slot feed type antenna according to claim 1, wherein a matching means is provided inside the waveguide space.