Slot array antenna

Abstract

To achieve a slot array antenna capable of facilitating manufacturing.SOLUTION: A slot array antenna 4 including a radiating plate 2 and a base plate 1 is provided. The radiating plate 2 has a first surface having a plurality of slots 22 radiating radio waves and a horn shape with both sides of the first surface curved in a shorter side direction. The radiating plate further has first and second connecting members 25, 26 that are protrusions bent in the direction opposite to the direction of radio wave radiation at both ends in the longer side direction of the first surface. The base plate has a U-shape and has first and second notches 14, 15 at both ends in the longer side direction. The first and second connecting members 25, 26 of the radiating plate 2 are inserted into the first and second notches 14, 15 of the base plate 1.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention mainly relates to a slot array antenna for ships.

Background Art

[0002] In conventional ship antennas, in order to improve directivity, a slot array antenna using a rectangular waveguide having a plurality of slots or a patch array antenna (hereinafter also referred to as a patch antenna) having a plurality of patches has been used. The patch antenna is inexpensive and easy to manufacture because it is formed on a substrate, but it has a larger loss and lower gain than the slot array antenna.

[0003] A slot array antenna is an antenna in which slots are provided in a waveguide. Here, a lid is required at the end of the waveguide. Generally, a short-circuit plate (metal plate) is used in the resonance type method, and a terminator (radio wave absorber) is used in the traveling wave type method.

[0004] Since the waveguide is a rectangular tube, generally the lid needs to be separately manufactured and attached. In addition, it is necessary to grind the waveguide with high precision and perform slot processing. Since the lid is separately manufactured and attached, it is necessary to cut the waveguide with high precision and perform slot processing, which requires advanced technology and a lot of time for manufacturing.

[0005] As described above, the waveguide slot array antenna has small loss and high gain, but requires high-precision processing and is time-consuming and costly. Therefore, an antenna that is easier to process than a rectangular waveguide and has better performance than a patch antenna is expected.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] In an effort to create antennas using a simpler method, antennas made by processing multiple metal plates (metal sheets), as shown in Patent Document 1, have been developed. However, horns made from these metal plates need to be connected to waveguides, and this connection requires the use of many fastening members such as screws, making them still difficult to manufacture easily. [Overview of the project] [Problems that the invention aims to solve]

[0008] The present invention provides a slot array antenna that is easy to manufacture. [Means for solving the problem]

[0009] The present invention provides a slot array antenna comprising a radiating plate and a base plate. The radiating plate has a first surface having a plurality of slots for radiating radio waves, and both sides of the first surface in the short-range direction are curved to form a horn shape. The radiating plate also has first and second connecting members, which are projections curved in the opposite direction to the direction of radio wave radiation, at both ends in the long-range direction of the first surface. The base plate has a U-shape and has a first notch and a second notch at both ends in the long-range direction. The first and second connecting members of the radiating plate are inserted into the first and second notches of the base plate. This configuration provides a slot array antenna that is easy to manufacture.

[0010] Furthermore, a waveguide through which radio waves propagate may be formed between the U-shape and the first surface of the radiating plate. This configuration allows for easy construction of the waveguide.

[0011] Furthermore, the first and second connecting members may act as short-circuits for radio waves within the waveguide. This configuration allows for efficient excitation.

[0012] Furthermore, the first and second connecting members may also be rectangular in shape.

[0013] Furthermore, the length of the longer side of the connecting member may be less than or equal to the depth of the U-shape of the base plate. This configuration eliminates the need to precisely match the length of the connecting member to the depth of the U-shape, allowing for a simpler structure to confine radio waves within the waveguide.

[0014] Furthermore, the base plate may have a third notch on the outside in the long-side direction of the first notch, and a fourth notch on the outside in the long-side direction of the second notch.

[0015] Furthermore, the grating plate further comprises a grating surface having a grid, and third and fourth connecting members at both ends in the long-side direction, curved in the opposite direction to the direction of radio wave radiation, wherein the third and fourth connecting members of the grating plate may be inserted into third and fourth notches. This configuration allows the grating plate to be easily attached.

[0016] Furthermore, the grating of the plate may suppress vertical polarization, which is a noise signal.

[0017] Furthermore, the base plate, radiating plate, and grating plate may have multiple holes into which fasteners for securing them to each other are inserted.

[0018] Furthermore, the base plate may have a feed point for supplying radio waves.

[0019] Furthermore, the feed point may be located in the center along the longer side of the base plate. This configuration makes it easier to construct the antenna.

[0020] Furthermore, the number of slots on the first surface of the radiating plate may be odd.

[0021] Furthermore, the angle of the central slot of multiple slots and the distance to the feed point may be fixed to a distance that supplies in-phase radio waves to each slot. With this configuration, in-phase radio waves are supplied from each slot.

[0022] In another aspect of the present disclosure, a method of assembling a slot array antenna is provided. In the assembling method, a plurality of slots for radiating radio waves are formed on a first surface of a radiation plate, both ends in the short side direction of the first surface are bent to form a horn shape, and first and second connection members which are protrusions bent in a direction opposite to the radio wave radiation direction are formed at both ends in the long side direction of the first surface, a U-shaped base plate is formed, first and second cutouts are formed in the vicinity of both ends of the base plate, and the first and second connection members of the radiation plate are inserted into the first and second cutouts of the base plate.

[0023] The slot array antenna of the present invention is composed of a combination of metal plates manufactured by press working. The assembly of the metal sheets is facilitated by providing connection members to the radiation and grating plates and providing cutouts corresponding to the base plate. Thereby, the radiation plate and the grating plate are assembled to the base plate, and a slot array antenna for radiating radio waves is formed. Thus, it is possible to realize an antenna that is easier to manufacture than a conventional slot array antenna and has a higher gain than a conventional patch antenna.

Brief Description of Drawings

[0024] The drawings for maintaining this lesson facilitate the understanding of the embodiments and are not intended to limit the disclosed configuration and results. Here, the same configuration is denoted by the same reference numerals throughout. [Figure 1] FIG. 1 shows a state in which the base plate, radiation plate, and grating plate of the slot array antenna are separated. [Figure 2] FIG. 2 shows the structure of the connection between the radiation plate and the base plate in the slot array antenna. [Figure 3] FIG. 3 shows the connection structure between the grating plate and the base plate in the slot array antenna. [Figure 4] FIG. 4 is an overall view of the slot array antenna. [Figure 5] FIG. 5 shows a cross-sectional view of the slot array antenna. [Figure 6] FIG. 6 is a radiation pattern related to radio wave radiation. [Figure 7] Figure 7 is a graph showing a comparison of the gains of a slot array antenna and a patch antenna. [Figure 8] Figure 8 is a flowchart showing how to assemble a slot array antenna. [Modes for carrying out the invention]

[0025] The present invention is not limited to other exemplary embodiments or features, and various modifications are possible within the scope of the technical idea presented herein. The following detailed description will refer in part to the accompanying drawings.

[0026] The present invention can be arranged, replaced, combined, separated, and designed in a wide variety of different configurations, to the extent shown herein and in the drawings.

[0027] Figure 1 shows the base plate 1, radiating plate 2, and grating plate 3 of a slot array antenna (shown in Figure 4 below). The slot array antenna includes the base plate 1, the radiating plate 2, and the grating plate 3.

[0028] As shown in Figure 1, the base plate 1 has first, second, and third surfaces 11, 12, and 13 that form a U shape. The base plate 1 also has first and second notches 14 and 15 near its ends. Specifically, the first notch 14 is formed as a slit near the respective ends of the first and third surfaces 11 and 13 of the base plate 1. Similarly, the second notch 15 is formed as a slit on the opposite side of the first notch 14, near the respective ends of the first and third surfaces 11 and 13 of the base plate 1. The width of each slit is greater than or equal to the thickness of the radiation plate 2.

[0029] Furthermore, the base plate 1 has third and fourth notches 16 and 17 near its ends. Specifically, the third notch 16 is formed as a slit near the ends of the first and third surfaces 11 and 13 of the base plate 1. Similarly, the fourth notch 17 is formed as a slit near the ends of the first surface 11 and the third surface 13 of the base plate 1. The width of each slit is greater than or equal to the thickness of the radiation plate 2.

[0030] The first and third notches 14 and 16, located near the edge of the base plate 1, have a predetermined gap between them, with the third notch 16 positioned closer to the edge of the base plate 1 and the first notch 14 positioned inward with a predetermined gap between them. Similarly, the second and fourth notches 15 and 17, located near the opposite ends of the base plate 1 in the long-side direction, have the fourth notch 17 positioned closer to the edge of the base plate 1 and the second notch 15 positioned inward with a predetermined gap between them.

[0031] The radiating plate 2 has a first surface 21 having a plurality of slots 22 for radiating radio waves, and second and third surfaces 23 and 24 that form a horn shape. The first, second, and third surfaces 11, 12, and 13 of the base plate 1 and the first surface 21 of the radiating plate form a waveguide. The waveguide thus formed is an elongated rectangular waveguide. The base plate 1 further includes a feed point 20 for feeding radio waves to the slot array antenna. The feed point 20 is located at the center of the base plate 1. Specifically, the feed point 20 is located at the center of the third surface 13 of the base plate 1. The plurality of slots 22 on the first surface 21 of the radiating plate 2 have an odd number of slots, and each slot is formed at a predetermined angle. The slot angles of the central slots of the plurality of slots 22 and the distance to the feed point 20 are predetermined so that in-phase radio waves are fed to each slot.

[0032] Furthermore, the radiating plate 2 has a connecting member 25 and another connecting member 26 at the end of the first surface 21 of the radiating plate 2, which are bent in the direction opposite to the direction of radiation of radio waves. The connecting members 25 and 26 of the radiating plate 2 have a rectangular shape. In other embodiments, the connecting members 25 and 26 of the radiating plate 2 can have any shape that can be joined to the base plate, such as a square, ellipse, or rod shape. The length of the connecting members 25 and 26 of the radiating plate 2 is less than or equal to the U-shaped depth of the base plate 1.

[0033] The grating plate 3 has connecting members 32 and 33 at both ends of the grating surface 31, which are bent in the direction opposite to the direction of radiation of radio waves. The connecting members 32 and 33 of the grating plate 3 have a rectangular shape. In other embodiments, the connecting members 32 and 33 of the grating plate 3 may have any shape that can be joined to the base plate, for example, they may be square, elliptical, or rod-shaped. The length of the connecting members 32 and 33 of the grating plate 3 is greater than or equal to the depth of the U-shape of the base plate 1.

[0034] The base plate 1, the radiating plate 2, and the grating plate 3 are metal plates that have been bent and punched to form the desired design. The base plate 1, the radiating plate 2, and the grating plate 3 may be made from the same metal or from different metals. Also, the base plate 1, the radiating plate 2, and the grating plate 3 have the same thickness.

[0035] Figure 2 shows the structure of the connection between the radiating plate 2 and the base plate 1. The radiating plate 2 is connected to the base plate 1 via connecting members 25 and 26 of the radiating plate 2, and the first and second notches 14 and 15 of the base plate 1. The distance between connecting member 25 and connecting member 26 of the radiating plate 2 is equal to the distance between the first notch 14 and the second notch 15 of the base plate 1.

[0036] The connecting members 25 and 26 of the radiating plate 2 can be inserted into the first and second notches 14 and 15, respectively. The connecting member 25 of the radiating plate 2 is inserted by sliding it into the first notch 14 (slit) at the edges of the first and third surfaces 11 and 13 of the base plate 1. Similarly, the connecting member 26 of the radiating plate 2 is inserted by sliding it into the second notch 15 (slit) at the edges of the first and third surfaces 11 and 13 of the base plate 1. The connecting members 25 and 26 of the radiating plate 2 act as short circuits for radio waves in the waveguide.

[0037] Figure 3 shows the structure of the connection between the grating plate 3 and the base plate 1. The grating plate 3 is connected to the base plate 1 via connecting members 32 and 33, and the third and fourth notches 16 and 17 of the base plate 1. The distance between the connecting members 32 and 33 of the grating plate 3 is equal to the distance between the third and fourth notches 16 and 17 of the base plate 1. The distance between the connecting member 32 and the connecting member 33 of the grating plate 3 is greater than the distance between the connecting member 25 and the connecting member 26 of the radiating plate 2. Also, the distance between the third notch 16 and the fourth notch 17 of the base plate 1 is greater than the distance between the first notch 14 and the second notch 15 of the base plate 1.

[0038] The connecting members 32 and 33 of the grating plate 3 are inserted into the third and fourth notches 16 and 17, respectively, to assemble a slot array antenna for radio wave radiation and suppress noise signals associated with radio wave radiation. The noise signals are vertically polarized. The connecting member 32 of the grating plate 3 can be slid into the third notch 16 (slit) at the edges of the first and third surfaces 11 and 13 of the base plate 1. Similarly, the connecting member 33 of the grating plate 3 can be slid into the fourth notch 17 (slit) at the edges of the first and third surfaces 11 and 13 of the base plate 1. The grating plate 3 is used for cross-polarization suppression.

[0039] Each of the base plate 1, the radiating plate 2, and the grating plate 3 has a plurality of holes 19, 27, and 34, respectively, for receiving fasteners to secure them to each other. Examples of fasteners used to secure the base plate 1, the radiating plate 2, and the grating plate 3 to each other include, but are not limited to, threaded fasteners such as screws, nuts, and bolts. The base plate 1 has a fourth and fifth surface 18a, 18b adjacent to and perpendicular to the first and third surfaces 11, 13 of the base plate 1, respectively. The fourth and fifth surfaces 18a, 18b include a plurality of holes 19. The first surface 21 of the radiating plate 2 includes a plurality of holes 27.

[0040] Figure 4 shows the assembled slot array antenna 4. The base plate 1, radiator plate 2, and grating plate 3 are assembled as described in Figures 2 and 3 to form the slot array antenna 4. The slot array antenna 4 is used in radar equipment used for navigation on ships. The radiator plate 2 is attached to the base plate 1 via the first and second notches 14, 15 and connecting members 25, 26 of the radiator plate 2, as described in Figure 2. The grating plate 3 is attached to the base plate 1 via the third and fourth notches 16, 17 and connecting members 32, 33 of the grating plate 3, as described in Figure 3. The base plate 1, radiator plate 2, and grating plate 3 are fastened to each other using fasteners through a number of holes 19, 27, 34.

[0041] Since the radiating plate 2 has connecting members 25 and 26 that function as short circuits for radio waves, the slot array antenna 4 can be used as a resonant type. When an absorber is attached to the radiating plate 2, the slot array antenna 4 can also be used as a traveling wave type.

[0042] The size (i.e., height) of the waveguide formed by the first, second, and third surfaces 11, 12, and 13 of the base plate 1 and the first surface 21 of the radiating plate 2 is such that higher-order modes of radio waves do not occur. The base plate has a fourth and fifth surface 18a and 18b, formed by bending the outer edges of the first surface 11 and the third surface 13 of the base plate (hereinafter referred to as the bent portion). The fourth and fifth surfaces 18a and 18b are the surfaces that come into contact with the radiating plate 2. Furthermore, because the bent portion reduces the contact area between the fourth and fifth surfaces 18a and 18b and the radiating plate 2, even if the height of the waveguide is shorter than the height of the slot, it is not necessary to provide a cutout for the slot in the base plate, and radio waves can be transmitted and received without interference with the slot. The curvature of the fourth and fifth surfaces 18a and 18b of the base plate 1 can be adjusted as appropriate in response to interference with the slot. As a result, while conventional slot array antennas required notches in the slots in addition to the slot surfaces, it is not necessary to cut the slots in the bent sections, making processing easier. Thus, the slot array antenna 4 of this disclosure is structurally stable even though it is easy to assemble.

[0043] Figure 5 shows a cross-sectional view of the slot array antenna 4. Radio waves are fed via a feed line 5 located at the feed point 20. The slot array antenna 4 is a resonant slot array antenna with both ends short-circuited via connecting members 25 and 26. The number of slots 22 is odd, and slots are also provided near the feed point 20. The slot angle of the central slot and its distance from the feed point 20 are adjusted so that a desired weight can be obtained while feeding each slot with radio waves in phase. Figure 6 shows an example of a radiation pattern 6 related to the radiation of radio waves.

[0044] Figure 7 is a graph showing a comparison of the gain of the slot array antenna 4 and a conventional patch antenna. The graph shows that the gain of the slot array antenna 4 of the present invention is higher than that of a conventional patch antenna of the same size.

[0045] Figure 8 shows a flowchart illustrating method 8 for assembling a slot array antenna. Note that the order of assembly does not matter as long as the slot array antenna can be assembled.

[0046] In step 81, a radiation plate 2 is created having a first surface 21 with a plurality of slots 22 for emitting radio waves, second and third surfaces 23 and 24 that form a horn shape, and connecting members 25 and 26 that are bent at both ends of the first surface 21 in the direction opposite to the direction of radio wave emission.

[0047] In step 82, a base plate 1 is created having first, second, and third U-shaped surfaces 11, 12, and 13, and first and second notches 14 and 15 near the ends.

[0048] In step 83, the grating plate 3 is created. At this time, connecting members 32 and 33 are formed at both ends of the grating surface 31 of the grating plate 3, bending in the direction opposite to the direction of radio wave radiation. In addition, third and fourth notches 16 and 17 are formed near the ends of the base plate 1, respectively.

[0049] In step 84, the connecting members 25 and 26 of the radiating plate 2 are inserted into the first and second notches 14 and 15, respectively, to assemble the slot array antenna 4. Radio waves are radiated from the slots between the horn shapes.

[0050] In step 85, the connecting members 32 and 33 of the grating plate 3 are inserted into the third and fourth notches 16 and 17, respectively, to assemble the slot array antenna 4. [Explanation of symbols]

[0051] 1 Base plate 2 Radiation plates 3. Grating 4-slot array antenna 14-17 First to fourth notches 25, 26 Connecting members for radiating plates 32, 33 Connecting members for grating panels

Claims

1. A radiating plate having a first surface with multiple slots for emitting radio waves, wherein both sides of the short side direction of the first surface are curved to form a horn shape, A base plate having a U-shape, Equipped with, The radiating plate has first and second connecting members, which are projections curved in the opposite direction to the direction of radiation of radio waves, at both ends of the long side direction of the first surface. The base plate has first and second notches near both ends in the direction of the longer side, The first and second connecting members of the radiating plate are inserted into the first and second notches of the base plate. Slot array antenna.

2. The U-shape and the first surface of the radiating plate form a waveguide through which the radio waves propagate. The slot array antenna according to claim 1.

3. The slot array antenna according to claim 2, wherein the first and second connecting members form a short-circuit for the radio waves propagating through the waveguide.

4. The first and second connecting members are rectangular in shape. The slot array antenna according to claim 1.

5. The slot array antenna according to any one of claims 1 to 4, wherein the length of the long side of the first and second connecting members is less than or equal to the depth of the U-shape of the base plate.

6. The base plate has a third notch on the outer side in the long-side direction of the first notch, and a fourth notch on the outer side in the long-side direction of the second notch. The slot array antenna according to claim 1.

7. A grating plate having a grating surface with a grid, and third and fourth connecting members at both ends in the long side direction that are curved in the opposite direction to the direction of radiation of radio waves, Furthermore, The third and fourth connecting members of the grating plate are inserted into the third and fourth notches, The slot array antenna according to claim 6.

8. The slot array antenna according to claim 7, wherein the grid of the grating plate suppresses vertical polarization, which is a noise signal.

9. The slot array antenna according to claim 7 or 8, wherein the base plate, the radiating plate, and the grating plate have a plurality of holes into which fasteners for fixing them to each other are inserted.

10. The slot array antenna according to claim 9, wherein the base plate has a feed point for supplying radio waves.

11. The slot array antenna according to claim 10, wherein the feed point is located in the center of the long side of the base plate.

12. The slot array antenna according to claim 1, wherein the distance between the first and second connecting members is equal to the distance between the first and second notches.

13. The slot array antenna according to claim 1, wherein the number of the plurality of slots on the first surface of the radiating plate is odd.

14. Multiple slots for emitting radio waves are formed on the first surface of the radiating plate. The ends of the first surface in the short-side direction are bent to form a horn shape, First and second connecting members, which are protrusions curved in the opposite direction to the direction of radio wave radiation, are formed at both ends of the long side of the first surface. A U-shaped base plate is formed, First and second notches are formed near both ends of the base plate. Insert the first and second connecting members of the radiating plate into the first and second notches of the base plate. How to assemble a slot array antenna.

15. A grating plate with a grid is formed, The ends of the long side of the grating plate are bent in the direction opposite to the direction of radio wave radiation to form the third and fourth connecting members. Third and fourth notches are formed near both ends of the base plate, The third and fourth connecting members of the grating plate are inserted into the third and fourth notches, respectively. A method for assembling a slot array antenna according to claim 14.

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