JPS60171807A - Slot array antenna system - Google Patents

Abstract

PURPOSE:To attain low side lobe level of a slot array antenna system by arranging respectively at least one outward face or an inward face of a couple of dielectric board in a way not in parallel with a corresponding face of other dielectric board. CONSTITUTION:A slot waveguide 1 is inserted and fixed to a slot 2a of a web of a channel member 2. A couple of dielectric boards 3a, 3b sufficiently thin in comparison with the operating wavelength are provided to the front end of the waveguide 1. Moreover, the reflecting plate 4 is provided at its outside. The dielectric boards 3a, 3b are fixed so that prolonged lines of each outward face approach together at the tip. In increasing the titled angle of the dielectric boards 3a, 3b, the side lobe level is decreased. The dielectric boards 3a, 3b have only to be folded or an angle has only to be given to a fitting part in order to increase said angle.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a slot array antenna device suitable as an antenna for a marine radar, a relay device, etc. This article relates to a slot array antenna family H that aims to reduce weight.

``Prior art J Slot array Φ antenna devices are smaller and lighter than parabolic antennas, etc., so they are often used in marine radars that need to be mounted on masts, etc. However, slot waveguides alone are not suitable for this purpose. A directional beam can only be formed within a plane containing the tube axis of the slot waveguide (hereinafter referred to as a horizontal plane), and a directional beam can only be formed in a plane perpendicular to the horizontal plane (hereinafter referred to as a vertical plane).

) cannot be formed, so a horn is usually mounted and used to obtain a directional beam in the vertical plane. Therefore, even if it is not as sharp as the Nokura Polar antenna, trying to obtain a sharp beam increases the weight and the aperture area, making it difficult to use outdoors.
The disadvantage is that the influence of wind pressure becomes greater. In particular, the issue of wind pressure is extremely important for marine radars used on windy seas, as this has a great effect on not only the strength of the radar itself but also the rotational drive system.

In response, the present applicant has created a slot with a dielectric waveguide mechanism and a small reflector, and by replacing the horn with a small reflector and reducing the size, the size and weight of the horn are reduced, and the opening area is kept small. - Proposed an array φ antenna device (Japanese Patent Application Laid-Open No. 56-31205).

Figure w41 and Figure 2 show an example of this slot O-array antenna device.The slot-array e antenna device shown in these figures has a structure 2 & provided in the web of the channel member 2, and a groove 2a. A slot waveguide 1 is inserted and fixed, and at the front end of the slot waveguide 1, a pair of dielectric plates 3a and 3b whose thickness is sufficiently thin compared to the wavelength used is provided with a space in front of the front end in between. A reflecting plate is provided on the outside of the pair of dielectric plates 3a and 3b to reflect electromagnetic waves transmitted through the vicinity of the bases of the dielectric plates 3a and 3b. 4 is provided at the opening of the channel member 2.

Of the electromagnetic waves radiated from the slot waveguide, this slot-7 ray and antenna device directs those radiated at a small angle with respect to the horizontal plane to the inward surfaces of the dielectric plates 3a and 3b (opposite surface) and guide it forward,
By reflecting the radiation emitted at a large angle forward at the reflector plate 4, the electromagnetic wave energy emitted forward is increased, a directional beam is formed, and the side lobe level is reduced. I'm letting you do it.

In this case, the reflector plate 4 only needs to reflect electromagnetic waves emitted from the dielectric base at a large angle, so it can be short, and the opening area can be made smaller than that of a conventional horn, for example. In the case of conventional horn-type antennas, the aperture height was more than four times the wavelength used, but in the case of this slot array antenna device, the height of the aperture is only about twice the wavelength, making it possible to reduce the aperture area. can.

-1 Although the slot array antenna device shown in FIGS. 1 and 2 described above is sufficiently practical on its own, it may be required to further reduce the sidelobe level.

In response to this, it is possible to deal with this by changing the material, length, etc. of the dielectric plate, changing the channel member, changing the length of one reflecting plate, changing the mounting angle, etc.

However, with this method, it is necessary to prepare a variety of parts depending on the specifications, the production process becomes complicated, and the weight and opening area increase. It was not easy to realize this.

``Object of the Invention'' The present invention was made in view of the problems listed in L. By simply changing the shape and mounting condition of the dielectric plate, the sidelobe level can be reduced without increasing the single-layer product and opening area. It is an object of the present invention to provide a slot-array-antenna device that can be formed without having to prepare various parts other than a dielectric plate, and without complicating the production process.

Arrangement 1 of the Invention In order to achieve the above object, the arrangement of the present invention is to provide a pair of dielectric plates at the front end of the slot waveguide, with a space in front of the front end in between, the plate thickness of which is sufficiently thin compared to the wavelength used. A slot array antenna device comprising a protruding body plate and a reflecting plate provided on the outside of the pair of dielectric plates to reflect electromagnetic waves transmitted through the vicinity of the base of the dielectric plates and emitted, The pair of dielectric plates are arranged such that at least one of an outward facing surface or an inward facing surface of each dielectric plate is non-parallel to the corresponding surface of the other dielectric plate. do.

In the above configuration, although the operation of the present invention is not necessarily theoretically clear, it can be thought of as follows.

When the dielectric plates of a plane-parallel plate are arranged in a non-parallel manner, the angle of incidence of electromagnetic waves on the dielectric plates becomes smaller than when they are arranged in parallel due to the inclination of the inward surfaces of the pair of dielectric plates. , the transmittance of electromagnetic waves increases, the electromagnetic waves are reflected by the reflector, and the amount of electromagnetic waves traveling forward increases.

On the other hand, for the same reason, the angle between the electromagnetic waves reflected by the inward surfaces of the pair of dielectric plates and the horizontal plane is extremely small.

continues to move forward. As a result, the forward radiant energy increases, the lateral (vertical direction) radiant energy decreases, and the side lobe level is kept low.

In addition, when using wedge cedar dielectric plates in a non-parallel arrangement, the electromagnetic waves that pass through the dielectric plates are largely refracted toward the thicker side, similar to the refraction of light by a prism, so they are reflected. The electromagnetic waves reflected by the plate increase. That is, among the electromagnetic waves that pass through the dielectric plate, even waves that have not been reflected in the past are largely refracted, enter the reflector, and are reflected forward, increasing the forward radiant energy.

In either case, the reflector can be used effectively and the sidelobe level can be reduced without increasing the aperture area. Of course, since there is no need to increase the size of the reflector, the weight of the antenna does not increase.

1 Example 1 Embodiments of the present invention will be described with reference to the drawings.

In the first embodiment of the slot array antenna device of the present invention shown in FIGS. 3 and 4, a groove 2a is provided in the web of a channel member 2, and a slot waveguide l is inserted and fixed into the groove 2a. At the front end of the slot waveguide l, a dielectric waveguide mechanism 3 consisting of a pair of dielectric plates 3a and 3b, whose thickness is sufficiently thin compared to the wavelength used, is inserted across a space in front of the front end. and on the outside of the pair of dielectric plates 3a and 3b,
A reflecting plate 4 is provided at the opening of the channel member 2 to reflect electromagnetic waves transmitted through the vicinity of the bases of the dielectric plates 3a and 3b and emitted. Note that, except for the dielectric oil guiding mechanism 3, the other configurations are the same as those shown in FIG. 1 above.

The channel member 2 is made of a metal plate or a material with metal walls and acts similarly to a waveguide. Examples of materials with metal walls include JF, a metal layer on a plastic plate,
Some are deposited by plating or other means.

The dielectric waveguide mechanism 3 includes two dielectric plates 3a.

The dielectric plates 3a-, 3b1 are each made of a plate-shaped dielectric material slightly bent near the base, and the extension lines of the outward surfaces approach each other on the tip side. is fixed to the inside of the parallel piece of the channel member 2. The bending of the dielectric plate is the length of the chain plate.

The force of the beak varies depending on the length and opening angle of the reflector, 1
It is an extremely small angle of about 5 degrees to 5 degrees. However, if the parallel pieces of the channel member 2 are sloped, the dielectric plate does not need to be bent. Further, the parallel plane dielectric plate may be bent when attached to the channel member 2.

The inclination angle of the dielectric plates 3a and 3b has an effect on the sidelobe level, and according to the experiments of the present inventors, the larger the angle, the smaller the sidelobe level <tJX. However, if the angle is too large, the pattern of the main lobe will deteriorate, so the above angle range is preferable.

In addition, the dielectric plates 3a and 3b are thin enough in thickness compared to the wavelength, for example, plates with a thickness of 1/10 wavelength or less are used.
In the case of this embodiment, the plate thickness t is 0.078 mm. The plate thickness needs to be made thinner as the dielectric constant increases, and in this embodiment, a plate with a dielectric constant of about 2.8 is used. The reason for reducing the plate thickness is to prevent deterioration of the radiation pattern due to electromagnetic waves being trapped within the dielectric plate.

It is considered that the longer the length L of the dielectric plates 3a and 3b in the front-rear direction, the better, but considering the inward inclination, it is appropriate to set it to several times the wavelength λ.In this embodiment, 3.4 people It is.

Further, as the distance between the dielectric plates 3a and 3b becomes narrower, the side lobe level decreases. However, dielectric plates 3a and 3b
At the base of the channel member 2, if the opening width of the channel member 2 is made smaller than l/2, power radiation from the slot waveguide l is suppressed. This is more than 172 wavelengths. However, as long as the structure of the channel member 2 is different, the present invention is not limited to this. In this embodiment, the distance between the outward facing surfaces is 0.78λ. On the other hand, the distance d at the tip is determined by the length and inclination angle of the dielectric plates 3a and 3b, and is 0.69 in this embodiment.

The reflecting plate 4 is made of a metal plate or a plate having a metal wall surface, similar to the channel member 2, and in this embodiment, it is integrally provided in the opening of the channel member 2, similar to the one in FIG. It is being The sidelobe level of this reflecting plate 4 decreases as its length increases, but as the length increases, the wind pressure increases accordingly. Therefore, it is desirable that the wavelength be about twice the wavelength used, and in this embodiment, the number of wavelengths is 2, and 9 people. Further, the opening angle θ of the reflecting plate is determined through experiments in consideration of the incident angle of electromagnetic waves passing through the dielectric plate and the wind pressure. In this embodiment, it is 25 degrees.

In such a configuration, when electromagnetic waves are emitted from the slot waveguide l, the angle of incidence on the dielectric plates 3a and 3b is
Since the inclination angle of the dielectric plates 3a and 3b becomes smaller, the first
The transmittance is higher than in the parallel arrangement shown in the figure,
The electromagnetic waves traveling at a large angle with respect to the horizontal plane near the base ends of the dielectric plates 3a and 3b are mostly transmitted through the dielectric plate 3a and reflected by the reflection plate 4, as shown by Wl in FIG. and move forward.

Further, the electromagnetic waves that are incident on the dielectric plate at an angle larger than the above W1 do not enter the reflecting plate 4, but spread slightly forward and travel, as shown by W2 in the figure.

On the other hand, the electromagnetic waves incident on the dielectric plate 3a at an angle larger than W2 are reflected by the inward surface of the dielectric plate and travel forward, as shown by W3 in the figure. In this case, the electromagnetic waves that are reflected are only those with a large angle of incidence, so
The radiant energy is focused into a less divergent beam.

When the electromagnetic waves traveling like Wl, W2, and W3 are superimposed, the radiation pattern shown in FIG. 6 is obtained. The radiation pattern of the slot fist array antenna device shown in Fig. 1 above (Fig. )
In comparison, in the latter case, the sidelobe level was greater than -20 dB, but in the former case, that is, in this example, the side lobe level was -24 dB.
It becomes an extremely small level below dB (X).

In the above embodiment, the desired directional beam force (because of the symmetry, the dielectric plates 3a and 3b were referred to as the fourth term in the upper and lower sentences,
If the beam shape is asymmetric, it may be asymmetric;
For example, a configuration may be adopted in which only one of the dielectric plates is bent and the other is made into a parallel plane plate.

Next, in the second embodiment of the present invention shown in FIG.
, 3b is a wedge cedar board, a groove 2a is provided on the λ side of the protruding parallel piece of the channel member 2, and the slot waveguide 1 is fixed to the groove 2a4, and , the bases of wedge-shaped dielectric plates 3a, 3b are attached to the outside of the parallel pieces of the channel member 2, and furthermore, the reflector 4 is attached to the outside.

The wedge-shaped dielectric plates 3a and 3b each have an inclined surface facing outward and a surface facing inward parallel to each other.

Further, the reflection plate 4 is provided on a separate side from the channel member 2. However, the channel member 2 and the reflecting plate 4 have a wedge shape: A''+1!.

Body plates 3a and 3b may be attached. Further, the channel member 2 and the reflecting plate 4 are formed of a metal plate or a plate having a metal wall surface, as in the first embodiment.

According to this embodiment, the opposing surfaces of the dielectric plates 3a and 3b are parallel, and the outward surfaces are each inclined at l/x, so that electromagnetic waves from the slot waveguide 1 toward the dielectric plates 3a and 3b Among these, the electromagnetic waves reflected between the opposing surfaces proceed in the same manner as shown in FIG. On the other hand, since the electromagnetic waves incident on the dielectric plates 3a and 3b are refracted to a large extent, even waves that would not otherwise be incident are incident on the reflection plate 4, reflected, and proceed forward.

This increases the forward radiant energy and
Sidelobe levels are reduced.

In this embodiment, the wedge-shaped dielectric plate 3a is used.

Although the inward surfaces of the dielectric plates 3b are arranged parallel to each other, the dielectric plates 3a and 3b may be arranged non-parallelly by bringing the opposing inward surfaces closer to each other. Alternatively, the inclined surface may be an inward facing surface, the non-inclined surface may be an outward facing surface, and the outward facing surfaces may be arranged in parallel.

Since the tips of the wedge-shaped dielectric plates 3a and 3b gradually become thinner, the electromagnetic waves trapped inside are radiated to the outside, so there is an advantage that pack lobes due to reflection at the tips can be reduced.

In the above embodiment, wedge-shaped dielectric plates 3a and 3b having one slope were used, but a wedge-shaped dielectric plate having two slopes and a V-shaped cross section may also be used. Further, in the above embodiment, the upper and lower wedge-shaped dielectric plates are arranged symmetrically, but they may be disposed asymmetrically. Furthermore, wedge-shaped dielectric plates with different shapes may be arranged at the upper and lower sides. .

In addition, - in each of the above-mentioned embodiments, the reflecting plate 4 is constituted by a flat plate, but it may be a curved plate such as a paraboloid.

Effects of the Invention J As explained below, the present invention provides a slot Φ array antenna device equipped with a dielectric waveguide mechanism, in which a pair of dielectric plates are connected to each other on either the outward or inward surface of the dielectric plates. By arranging at least one side non-parallel to the corresponding surfaces of the other dielectric plates, weight and opening area can be increased simply by changing the shape and mounting condition of the dielectric plates. It is possible to reduce the sidelobe level without having to use a bent dielectric plate or a wedge-shaped dielectric plate, and there is no need to prepare various parts, and the production process is not complicated. This has the effect of making it possible to form an antenna without any damage.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of a slot array antenna device equipped with a dielectric waveguide mechanism, FIG. 2 is a sectional view thereof, and FIG. 3 is a first embodiment of the slot array antenna device of the present invention. FIG. 4 is a sectional view thereof, FIG. 5 is an explanatory view showing the operation of the first embodiment, and FIG.
A characteristic diagram showing the measured radiation pattern of the example shown in FIG. 7, a characteristic diagram showing the measured radiation pattern of the example shown in FIG.
The figure is a sectional view showing a second embodiment of the slot array antenna device of the present invention. 1...Slot waveguide 2...Channel member 3...Dielectric waveguide mechanism 3a, 3b...Dielectric plate 4...Reflector Applicant Tokyo Keiki Co., Ltd. Agent Patent attorney Iwao Mishina 4th ', m! 1 Figure 5 Figure 8 4) 3b Figure 6 (dEl) Figure 7 (dB) Procedural amendments stamped) 1985/5/! Day 1, Indication of the case: Japanese Patent Application No. 59-27722 2, Title of the invention: Slot array antenna device 3, Relationship with the person making the amendment: Address of the patent applicant: 2-16-46 Minami Kamata, Ota-ku, Tokyo Title (338) Tokyo Keiki Co., Ltd. 4, Agent 220 5, Claims column of the specification to be amended, Detailed explanation of the invention column 6 of the specification, Contents of the amendment (a ) In the 20th line of page 3 of the specification, the phrase "At the front end of the waveguide l, with a space in front of the front end in between" has been replaced with [Waveguide 1
In front of, across the space in front of, ”Correct. On page 6, line 6 of the specification, the phrase "at the front end of the waveguide, across the space in front of the front end," has been corrected to "At the front of the waveguide, across the space in front of the front end." do. (c) On page 8, line 10 of the specification, the phrase "at the front end of the waveguide l, across the space in front of the front end" has been replaced with "the waveguide l
In front of, with a space in front of, ``Correct. Claims as amended above: (1) A pair of dielectric plates are protrudingly provided in front of the slot waveguide, sandwiching a space in front of the slot waveguide, and the plate thickness is sufficiently thin compared to the wavelength used, and In the in-slot array antenna device, a reflector is provided on the outside of the pair of dielectric plates to reflect electromagnetic waves transmitted through the vicinity of the base of the dielectric plate and emitted. A slot array antenna device characterized in that at least one of the outward facing surface and the inward facing surface of the body plate is disposed so as to be non-parallel to the corresponding surface of another dielectric plate. . (2)-h The slot array antenna device according to claim 1, wherein a parallel plane plate is used as the dielectric plate, and the dielectric plates are made non-parallel so that their tip sides approach each other. (3) The slot array antenna device according to claim 1, wherein a wedge cedar board is used as the dielectric plate.

Claims (3)

[Claims] (1) At the front end of the slot waveguide, a pair of dielectric plates, whose thickness is sufficiently thin compared to the wavelength used, are provided protrudingly across a space in front of the front end, and the pair of dielectric plates are In a slot array antenna device that is provided with a reflector on the outside that reflects electromagnetic waves that are transmitted through the vicinity of the base of the dielectric plate and is emitted, the pair of dielectric plates is connected to the outer surface of the dielectric plate or A slot array antenna device characterized in that at least one of the inward facing surfaces is disposed so as to be non-parallel to the corresponding surfaces of other dielectric plates. (2) The slot array antenna device according to claim 1, wherein a parallel plane plate is used as the dielectric plate, and the dielectric plate 8 is disposed non-parallel so that its tip side approaches. (3) The slot array antenna device according to claim 1, wherein a wedge cedar board is used as the dielectric plate.