JPH0323687Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is a vertical polarization suppressor that suppresses vertical polarization by being attached to a slot array antenna suitable as an antenna for a marine radar, a relay device, etc. Regarding.

[Prior Art] Slot array antenna devices are smaller and lighter than parabolic antennas and the like, so they are often used in marine radars that need to be mounted on a mast or the like. However, the slot waveguide alone can only form a directional beam within a plane (hereinafter referred to as the horizontal plane) that includes the tube axis of the slot waveguide.
A plane perpendicular to the horizontal plane (hereinafter referred to as a vertical plane)
Since a directional beam in the vertical plane cannot be formed, a horn is usually mounted and used to obtain a directional beam in the vertical plane.

An example is shown in FIG. The antenna device shown in the figure has a slotted waveguide 91 fitted into a holding member 92 made of a metal channel material, a horn 93 attached to the opening of the holding member 92, and
The opening of the horn 93 is provided with a grating 94 and a radome 95 for suppressing vertically polarized waves.

However, although this antenna device is not as sharp as a parabolic antenna, the weight increases when trying to obtain a sharp beam, and the aperture area also increases, making it more susceptible to wind pressure when used outdoors. There is. In particular, the problem 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.

The present applicant has also proposed 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 can be reduced, and the aperture area can be kept small. slot/
There is an array antenna device (Japanese Patent Laid-Open No. 56-31205).

FIG. 6 shows an example of this slot array antenna device. The slot array shown in the figure
The antenna device has a groove 2a in the web of the holding member 2.
The slotted waveguide 1 is inserted and fixed into the groove 2a, and a pair of plates, whose thickness is sufficiently thin compared to the wavelength used, is placed at the front end of the slotted waveguide 1 with a space in front of the front end in between. A dielectric waveguide mechanism 3 consisting of dielectric plates 3a and 3b is provided protrudingly, and the pair of dielectric plates 3
A reflective plate 4 is provided at the opening of the holding member 2 on the outside of the holding member 2 to reflect electromagnetic waves transmitted through the vicinity of the bases of the dielectric plates 3a and 3b and emitted.

These slot array antennas use horizontal polarization to increase long range detection capabilities when used in marine radars. Therefore, it is necessary to remove vertically polarized waves, which are unnecessary polarized components.

Vertical polarization suppressors used for this purpose conventionally include gratings and grids. For example, as shown in FIG. 5, the grating is constructed by attaching a large number of metal plates to the opening of the horn. Further, as shown in FIG. 7, the grid is constructed by providing a large number of slits 97 in a metal plate 96, and is attached to the front end of the slot waveguide.

When these gratings and grids are used, they become a new source of electromagnetic radiation, suppressing the vertical polarization and emitting only the horizontal polarization.

Furthermore, it is desirable for the slot array antenna to have a uniform phase plane of radiated electromagnetic waves and to reduce side lobes. When the above-mentioned grid or grating is used as a vertical polarization suppression mechanism, the limit of this side lobe is usually about -25 dB. It is known that one of the causes of this is mutual coupling between adjacent slots of the slot waveguide.

To solve this problem, an auxiliary waveguide may be installed perpendicularly to the slot plane for each slot of the slotted waveguide to prevent mutual coupling. However, this method has the disadvantage that the structure of the slotted waveguide becomes complicated, the manufacturing time is labor-intensive, and the weight increases significantly.

On the other hand, a metal block with a concave cross section,
It has been proposed to install the waveguide between each slot at the front end of the slotted waveguide. According to this metal block type vertical polarization suppressor, vertical polarization can be suppressed and mutual coupling can be reduced. However, this metal block type vertical polarization suppressor has the disadvantage that it is expensive because it is formed one by one. In addition, since each waveguide must be attached to the slot waveguide one by one, it takes time to assemble.

[Purpose of the invention] The present invention was made in view of the above-mentioned problems, and its first purpose is to suppress vertical polarization, reduce mutual coupling, and realize low side lobes. The purpose is to provide a wave suppressor.

A second object of the present invention is to provide a vertical polarization suppressor that is lightweight, easy to manufacture, and inexpensive.

[Structure of the invention] In order to achieve the above object, the structure of the invention is to attach a plurality of slots at a predetermined interval to the front end of a slotted waveguide, and to emit light from each slot. In a vertically polarized wave suppressor that suppresses vertically polarized electromagnetic waves, a crest that protrudes forward between each slot and a trough that exposes the slot at the position of each slot are arranged at intervals between each slot. It is made up of a band-shaped corrugated plate formed continuously in a corresponding rectangular wave shape, and a notch part is provided in the widthwise center of each trough of the corrugated plate to fit with the front end of the slotted waveguide to be installed. and the corrugated plate is provided with a conductive layer that reflects electromagnetic waves on at least the inner wall surface of the valley, and further, the inner wall spacing of each valley is smaller than 1/2 of the wavelength of the electromagnetic wave used. It is characterized by:

[Operation of the invention] In such a configuration, the front end of the slotted waveguide is inserted into the notch of the corrugated plate, the peaks of the corrugated plate are positioned between the slots, and the troughs are located at the slots. As a result, the peaks of the corrugated plate protrude between the slots, thereby preventing mutual coupling between the slots.

Further, each slot is sandwiched in the space in front of the inner wall surface conductor layer at the valley portion of the corrugated plate. Since the peaks and troughs of the corrugated plate are shaped like rectangular waves, this wall faces the space in front of the slot vertically and in parallel. The interval between the inner walls of each valley is set to be smaller than 1/2 of the wavelength of the electromagnetic wave used. On the other hand, the width of the corrugated plate is larger than the front end width of the slot waveguide. Therefore, the vertically polarized wave component of the electromagnetic waves radiated from each slot is suppressed and not radiated, and only the unsuppressed horizontally polarized wave is radiated.

[Example] An example of the present invention will be described with reference to the drawings.

<Configuration of Embodiment> An embodiment of the vertical polarization suppressor of the present invention shown in FIG. 1 is composed of a corrugated plate 5 that has peaks 7 and troughs 8 formed in a rectangular wave shape and continues in a band shape. .

The corrugated plate 5 is made of, for example, FRP (fiber reinforced plastic) molded into a corrugated plate shape, and one surface thereof has,
A conductor layer 6 is provided by depositing a conductor such as metal by plating or other means. A notch 9 is provided at the center of the trough 8 in the widthwise direction of the corrugated plate, into which the front end of the slotted waveguide is fitted.

The size of the corrugated plate 5 and its peaks 7 and troughs 8 is determined by the dimensions of the slotted waveguide 1 to be installed, the spacing between the slots installed therein, and the wavelength of the radiated electromagnetic waves. .

For example, the width W1 of the corrugated plate 5 is the same as that of the slot waveguide 1.
The width W2 of the notch 9 is larger than the width of the front end surface of
The width is approximately equal to the width of the front end face of the slotted waveguide 1. The length of the corrugated plate 5 is determined in accordance with the length of the slotted waveguide to be installed. However, corrugated plate 5
It is not necessary to manufacture the waveguide according to the length of the slotted waveguide, but it can be manufactured to a certain length and used by cutting or connecting as necessary.

The length L1 of the ridges 7 in the longitudinal direction of the corrugated plate is determined from the relationship between the slot spacing and the spacing L2 of the troughs 8.
Further, the interval L2 between the valleys 8 is long enough to completely expose the corresponding slot in the valley 8, and on the other hand, it is set to a length smaller than 1/2 of the wavelength of the electromagnetic wave used. be. Furthermore, the depth D from the opening of the trough 8 to the notch 9 is set to be at least 1/2 of the wavelength of the electromagnetic waves used.

[Operation of the Embodiment] Next, the operation of the vertical polarization suppressor of the above embodiment will be explained using an example in which this is applied to the slot array antenna device shown in FIGS. 3 and 4.

Fig. 3 is a cross-sectional view showing an example of a slot array antenna device equipped with the vertical polarization suppressor of the present invention, and Fig. 4 is a view of the slot array antenna device as seen from the front. FIG. 3 is a front view of a main part showing a part.

The slot array antenna device shown in these figures basically has the same structure as the antenna device shown in FIG. 6 above, except that the holding member 2 and the reflecting plate 4 are constructed separately. be. That is, in this antenna device, the slot waveguide 1 is fixed to the web of the holding member 2, and the front end of the slot waveguide 1 is
A dielectric waveguide mechanism 3 consisting of a pair of dielectric plates 3a and 3b whose plate thickness is sufficiently thin compared to the wavelength used is provided protrudingly across a space in front of the front end, and the pair of dielectric plates 3a , 3b, a reflecting plate 4 is provided at the opening of the holding member 2 to reflect electromagnetic waves transmitted through the vicinity of the bases of the dielectric plates 3a, 3b and emitted. Therefore, it goes without saying that the vertical polarization suppressor of this embodiment can also be applied to the antenna device shown in FIG. 6 above.

This embodiment, which is applied to the antenna device configured as described above, has a notch 9 as shown in FIG.
is fitted onto the front end of the slotted waveguide 1 and attached to the slotted waveguide 1. In this case, each slot 1a is positioned in each valley 8, as shown in FIG. The corrugated plate 5 is fixed using an adhesive or the like. However, it may be configured such that the top and bottom in the width direction are sandwiched and fixed by other members. At this time, a suitable protrusion is provided on the inner wall side of the crest 7 of the corrugated plate 5, a through hole is provided in the protrusion, a screw is inserted into this through hole, and the screw is screwed together with the sandwiched member. It is also possible to have a structure in which it is worn.

The slot in which the corrugated plate 5 is installed in this way
In the array antenna device, the vertical polarization suppressor of this embodiment operates as follows. That is, since the slot waveguide 1 is installed diagonally with the slots 1a alternately opposite in the direction of inclination, the vertically polarized wave component of the electric field is canceled and the electromagnetic wave, which is mainly the horizontally polarized wave, is radiated. This horizontally polarized wave is radiated without being suppressed by the wave plate 5 because the width direction (vertical direction) of the wave plate 5 has a length of 1/2 wavelength or more and the wave plate 5 has an open end. On the other hand, the vertically polarized wave component is not completely canceled by the arrangement of the slots 1a. This slightly remaining vertically polarized component is generated by the fact that conductor layers 6 are provided on the inner wall surfaces 8a and 8b of the troughs 8 of the corrugated plate 5, and the interval L2 between the troughs 8 is longer than half the wavelength of the electromagnetic wave used. Because it is smaller than the rays, it is suppressed and not radiated to the outside.

Moreover, since each slot 1a is partitioned by the ridges 7 of the corrugated plate 5, mutual coupling is extremely small. Therefore, the disturbance in the phase plane of the horizontally polarized wave to be emitted is also very small.

In this way, only horizontally polarized waves are radiated in front of the front end of the slot waveguide 1. Among these horizontally polarized waves, those radiated horizontally and those radiated at a slight angle with respect to the horizontal are radiated forward as they are or reflected by the dielectric plates 3a and 3b. Further, radiation emitted at a large angle with respect to the horizontal passes through the dielectric plates 3a and 3b, is reflected by the reflection plate 4, and is emitted forward.

Therefore, according to this embodiment, only horizontally polarized waves can be radiated, and there is no disturbance in the phase plane and no increase in side lobes. Furthermore, according to this embodiment,
Since a conductor layer is provided on a synthetic resin and formed on a corrugated sheet, it has the advantage of being easy to manufacture, inexpensive, and lightweight.

<Modification of the above embodiment> In the above embodiment, the corrugated plate is formed of synthetic resin, but it can also be formed using a thin metal plate.

Further, in the above embodiment, the conductor layer is provided on the entire surface of one side of the corrugated plate, but the conductor layer may be provided only on the inner wall surface of the trough. According to this, since the conductor layer becomes discontinuous at the top of the peak, mutual coupling is further reduced.

Furthermore, in the above embodiment and each modification,
Mutual coupling can also be reduced by providing a groove in the width direction (vertical direction) of the top of the peak to form a chiyoke structure.

[Effects of the invention] As explained above, in the present invention, by making the vertical polarization suppressor into a corrugated plate shape, firstly, vertical polarization is suppressed, and mutual coupling is reduced to achieve low side lobes. It has the effect of realizing

Secondly, it is lightweight and can be manufactured easily and inexpensively.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the vertical polarization suppressor of the present invention, FIG. 2 is a perspective view showing the vertical polarization suppressor of the above embodiment attached to a slot waveguide, and FIG. The figure is a sectional view showing an example of a slot array antenna device equipped with the vertical polarization suppressor of the present invention, and FIG.
Fig. 5 is a cross-sectional view showing an example of a horn-type slot array antenna device equipped with a grating, and Fig. 6 is a dielectric waveguide. FIG. 7 is a perspective view showing an example of a grid attached to the slot array antenna device having the dielectric waveguide mechanism. 1...Slot waveguide, 1a...Slot, 2
...Holding member, 3...Dielectric waveguide mechanism, 3a, 3
b...Dielectric plate, 4...Reflector plate, 5...Corrugated plate, 6
...Conductor layer, 7...Mountain part, 8...Trough part, 9...Notch part.

Claims (1)

[Claims for Utility Model Registration] A vertical waveguide that suppresses the vertical polarization of electromagnetic waves emitted from each slot by attaching it to the front end side of a slotted waveguide that has a plurality of slots arranged at predetermined intervals on the front end. In the polarization suppressor, the peaks projecting forward between the slots and the valleys exposing the slots are arranged in a continuous rectangular wave pattern corresponding to the spacing between the slots. The corrugated plate is made of a band-shaped corrugated plate, and the corrugated plate is provided with a notch in the widthwise center of each trough to fit with the front end of the slotted waveguide to be installed, and The plate is provided with a conductor layer that reflects electromagnetic waves at least on the inner wall surface of the valley, and further, the inner wall surface interval of each valley is made smaller than 1/2 of the wavelength of the electromagnetic wave used.・Vertical polarization suppressor for array antenna.