A directional antenna with high front-to-back ratio

Abstract

The invention discloses a high front-to-back ratio directional antenna, which relates to the field of radio and comprises: a metal back plate, a metal radiation patch, a first metal grating, a second metal grating, a metal feeding microstrip line, a dielectric plate, a feeding joint, a first plastic plate and a second plastic plate; the metal back plate is arranged at the bottom of the dielectric plate; the metal radiation patch is arranged at the top of the dielectric plate; the metal feeding microstrip line is arranged at the top of the dielectric plate and connected with the metal radiation patch; the feeding joint is arranged at the bottom of the metal back plate and passes through the dielectric plate to be connected with the metal feeding microstrip line; the first plastic plate and the second plastic plate are connected with the front and back side surfaces of the dielectric plate, the long side of the first metal grating is connected with the long side of the second metal grating, and the short side is connected with the first plastic plate and the second plastic plate; the first plastic plate and the second plastic plate are perpendicular to the common side; the invention reduces the antenna back lobe through the angle formed between the two metal gratings, improves the anti-interference ability and reduces the interference of the antenna to the rear direction.

Description

Technical Field

[0001] The present invention relates to the field of radio, and more particularly to a directional antenna with a high front-to-back ratio. Background Art

[0002] A directional antenna is an antenna that transmits and receives electromagnetic waves particularly strongly in one direction or in several specific directions, but transmits and receives zero or very small electromagnetic waves in other directions. In wireless communication systems, directional antennas can provide good signal coverage in a single direction. However, when the radiation front and back of the antenna is relatively low, it is susceptible to interference from the rear direction, or interferes with other antennas behind it.

[0003] The front-to-back ratio is used to measure the directivity of an antenna. It refers to the ratio of the energy in the maximum radiation direction to the energy radiated in the reverse direction. It depends on the energy left outside the antenna or wasted. In order to prevent energy waste, interference in the rear direction of the antenna and interference from other antennas, directional antennas need to achieve a high front-to-back ratio.

[0004] The prior art discloses a highly directional planar antenna based on a one-dimensional compound grating structure, comprising a monopole or dipole small feed, a metal base plate, a dielectric layer and an upper surface, characterized in that: the upper surface is composed of a designed number of periodic units one-dimensionally translated and tiled on the surface of the dielectric layer, each of the periodic units is composed of a rectangular metal grid with a long side of 200 mm and a short side of 20 mm, a rectangular metal grid with a long side of 200 mm and a short side of 6 mm, and a gap arrangement combination of the same width with a gap width of 1 mm; the dielectric layer thickness is 1.58 mm, and the dielectric constant of the medium is 2.65; this technical solution has a simple structural design and is easy to process, but the disadvantage is that the antenna has a weak anti-interference ability and is prone to interfere with other antennas behind. Summary of the invention

[0005] In order to solve the problem in the prior art that the antenna has weak anti-interference ability and is easy to interfere with other antennas at the rear, the present invention proposes a high front-to-back ratio directional antenna, which suppresses the backward radiation of electromagnetic waves and reduces the antenna back lobe through the angle generated between two metal gratings, and directs the antenna back lobe toward the interference source, thereby reducing the interference received by the antenna and reducing the interference generated by the antenna in the backward direction.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A high front-to-back ratio directional antenna, comprising: a metal back plate, a metal radiation patch, a first metal grating, a second metal grating, a metal feeding microstrip line, a dielectric plate, a feeding connector, a first plastic plate, and a second plastic plate;

[0008] The metal back plate is arranged at the bottom of the dielectric plate; the metal radiation patch is arranged at the top of the dielectric plate; the metal feed microstrip line is arranged at the top of the dielectric plate and connected to the metal radiation patch; the feed connector is arranged at the bottom of the metal back plate and passes through the dielectric plate to be connected to the metal feed microstrip line;

[0009] The first plastic plate is connected to the front side of the dielectric plate; the second plastic plate is connected to the rear side of the dielectric plate; the tops of the first plastic plate and the second plastic plate are both provided with a triangular structure;

[0010] The long side of the first metal grating is connected to the long side of the second metal grating, and the first metal grating and the second metal grating form an angle, and the angle is equal to the vertex angle of the triangular structure;

[0011] One end of the first metal grating is arranged on an inclined surface of the triangular structure of the first plastic plate, and the other end of the first metal grating is arranged on an inclined surface of the triangular structure of the second plastic plate; one end of the second metal grating is arranged on another inclined surface of the triangular structure of the first plastic plate, and the other end of the second metal grating is arranged on another inclined surface of the triangular structure of the second plastic plate; the angle is downward.

[0012] The working principle of the present invention is as follows:

[0013] The energy of the radiated back lobe is mainly composed of the diffraction wave at the edge of the metal back plate and the reflected wave of the grating. The phase and amplitude of the grating reflected wave are changed by adjusting the angle between the first metal grating and the second metal grating, so that the reflected wave and the diffraction wave of the metal back plate are completely offset, thereby reducing the energy of the radiated back lobe and improving the front-to-back ratio of the antenna. The antenna has a strong anti-interference ability in the direction of the back lobe. The back lobe of the antenna is pointed toward the interference source to reduce the interference received by the antenna and the interference of the antenna to the backward direction.

[0014] Preferably, it further comprises a first short-circuit metal sheet and a second short-circuit metal sheet;

[0015] The length of the dielectric plate is the same as that of the metal radiation patch;

[0016] The first short-circuit metal sheet is arranged between the first plastic plate and the dielectric plate; the second short-circuit metal sheet is arranged between the second plastic plate and the dielectric plate;

[0017] A long side of the first short-circuit metal sheet is connected to a wide side of the metal radiation patch;

[0018] The other long side of the first short-circuit metal sheet is connected to a wide side of the metal back plate;

[0019] One long side of the second short-circuit metal sheet is connected to the other wide side of the metal radiation patch;

[0020] The other long side of the second short-circuit metal sheet is connected to the other wide side of the metal back plate.

[0021] Furthermore, the metal radiation patch is a rectangular patch antenna;

[0022] The wide side of the rectangular patch antenna is vertical to the common side space of the first metal grating and the second metal grating.

[0023] Furthermore, the lengths of the first short-circuit metal sheet and the second short-circuit metal sheet are equal to the width of the rectangular patch antenna, and the widths of the first short-circuit metal sheet and the second short-circuit metal sheet are equal to the height of the dielectric plate.

[0024] Furthermore, the electric field polarization direction of the rectangular patch antenna is perpendicular to the common edge of the first metal grating and the second metal grating.

[0025] Preferably, the feed connector comprises a central feed pin and an outer conductor;

[0026] The central feeding needle is connected to the metal feeding microstrip line; and the outer conductor is connected to the metal back plate.

[0027] Preferably, the first metal grating and the second metal grating have the same size; the first metal grating and the second metal grating are planar structures, each comprising a plurality of rectangular metal sheets arranged at equal intervals; and the plurality of rectangular metal sheets have the same size, and the width of each rectangular metal sheet is greater than the spacing between adjacent rectangular metal sheets; the spacing between the rectangular metal sheets of the first metal grating is equal to the spacing between the rectangular metal sheets of the second metal grating; the long sides of the rectangular metal sheets are parallel to the common sides of the first metal grating and the second metal grating.

[0028] Furthermore, the projection areas of the first metal grating and the second metal grating are larger than the area of ​​the dielectric plate, and the lengths of the long sides of the first metal grating and the second metal grating are equal to the length of the dielectric plate.

[0029] Preferably, the metal back plate serves as a floor and produces directional radiation characteristics through reflection.

[0030] Preferably, the size of the dielectric plate is equal to that of the metal back plate, and the vertical distance from the dielectric plate to the common edge of the first metal grating and the second metal grating is greater than half of the vacuum wavelength corresponding to the operating frequency of the high front-to-back ratio directional antenna.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The angle between the first metal grating and the second metal grating suppresses the backward radiation of electromagnetic waves, reduces the back lobe of the antenna, and plays a role in improving the front-to-back ratio of the antenna.

[0033] 2. The anti-interference ability of the antenna back lobe direction is strong. Point the antenna back lobe direction toward the interference source to reduce the interference received by the antenna and the interference of the antenna to the backward direction, and reduce the energy radiated in unintended directions.

[0034] 3. Simple structure, easy to produce and process. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the structure of the high front-to-back ratio directional antenna.

[0036] Figure 2 It is a front cross-sectional view of the high front-to-back ratio directional antenna.

[0037] Figure 3 It is a comparison diagram of the plane radiation direction perpendicular to the common edge in the embodiment.

[0038] Among them: 1. metal back plate; 2. metal radiation patch; 3. first metal grating; 4. second metal grating; 5. metal feeding microstrip line; 6. dielectric plate; 7. feeding connector; 8. first short-circuit metal sheet; 9. second short-circuit metal sheet; 10. first plastic plate; 11. second plastic plate; 12. center feeding needle; 13. outer conductor. DETAILED DESCRIPTION

[0039] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] Example 1

[0041] In this embodiment, if Figure 1 As shown, a high front-to-back ratio directional antenna comprises: a metal back plate 1, a metal radiation patch 2, a first metal grating 3, a second metal grating 4, a metal feeding microstrip line 5, a dielectric plate 6, a feeding connector 7, a first plastic plate 10, and a second plastic plate 11;

[0042] The metal back plate 1 is arranged at the bottom of the dielectric plate 6; the metal radiation patch 2 is arranged at the top of the dielectric plate 6; the metal feeding microstrip line 5 is arranged at the top of the dielectric plate 6 and connected to the metal radiation patch 2; the feeding connector 7 is arranged at the bottom of the metal back plate and passes through the dielectric plate 6 to connect to the metal feeding microstrip line 5;

[0043] The first plastic plate 10 is connected to the front side of the dielectric plate 6; the second plastic plate 11 is connected to the rear side of the dielectric plate 6; the tops of the first plastic plate 10 and the second plastic plate 11 are both provided with a triangular structure;

[0044] The long side of the first metal grating 3 is connected to the long side of the second metal grating 4, and the first metal grating 3 and the second metal grating 4 form an angle, and the angle is equal to the vertex angle of the triangular structure;

[0045] One end of the first metal grating 3 is arranged on an inclined surface of the triangular structure of the first plastic plate 10, and the other end of the first metal grating 3 is arranged on an inclined surface of the triangular structure of the second plastic plate 11; one end of the second metal grating 4 is arranged on another inclined surface of the triangular structure of the first plastic plate 10, and the other end of the second metal grating 4 is arranged on another inclined surface of the triangular structure of the second plastic plate 11; the angle is downward.

[0046] The working principle of the present invention is as follows:

[0047] The energy of the radiated back lobe is mainly composed of the diffraction wave at the edge of the metal back plate and the reflected wave of the grating. The phase and amplitude of the grating reflected wave are changed by adjusting the angle between the first metal grating and the second metal grating, so that the reflected wave and the diffraction wave of the metal back plate are completely offset, thereby reducing the energy of the radiated back lobe and improving the front-to-back ratio of the antenna. The antenna has a strong anti-interference ability in the direction of the back lobe. The back lobe of the antenna is pointed toward the interference source to reduce the interference received by the antenna and the interference of the antenna to the backward direction.

[0048] In this embodiment, it also includes a first short-circuit metal sheet 8 and a second short-circuit metal sheet 9;

[0049] The length of the dielectric plate 6 is the same as that of the metal radiation patch 2;

[0050] The first short-circuit metal sheet 8 is arranged between the first plastic plate 10 and the dielectric plate; the second short-circuit metal sheet 9 is arranged between the second plastic plate 11 and the dielectric plate;

[0051] A long side of the first short-circuit metal sheet 8 is connected to a wide side of the metal radiation patch 2;

[0052] The other long side of the first short-circuit metal sheet 8 is connected to a wide side of the metal back plate 1;

[0053] One long side of the second short-circuit metal sheet 8 is connected to the other wide side of the metal radiation patch 2;

[0054] The other long side of the second short-circuit metal sheet 8 is connected to the other wide side of the metal back plate 1 .

[0055] More specifically, the metal radiation patch 2 is a rectangular patch antenna;

[0056] The wide side of the rectangular patch antenna is vertical to the common side space of the first metal grating 3 and the second metal grating 4 .

[0057] More specifically, the length of the first short-circuit metal sheet 8 and the second short-circuit metal sheet 9 is equal to the width of the rectangular patch antenna, and the width of the first short-circuit metal sheet 8 and the second short-circuit metal sheet 9 is equal to the height of the dielectric plate 6 .

[0058] More specifically, the electric field polarization direction of the rectangular patch antenna is perpendicular to the common edge of the first metal grating 3 and the second metal grating 4 .

[0059] In this embodiment, if Figure 2 As shown, the feeding connector 7 includes a central feeding pin 12 and an outer conductor 13;

[0060] The central feeding needle 12 is connected to the metal feeding microstrip line 5 ; the outer conductor 13 is connected to the metal back plate 1 .

[0061] In this embodiment, the first metal grating 3 and the second metal grating 4 have the same size; the first metal grating 3 and the second metal grating 4 are planar structures, each comprising a plurality of rectangular metal sheets arranged at equal intervals; and the plurality of rectangular metal sheets have the same size, and the width of each rectangular metal sheet is greater than the spacing between adjacent rectangular metal sheets; the spacing between the rectangular metal sheets of the first metal grating 3 is equal to the spacing between the rectangular metal sheets of the second metal grating 4; the long sides of the rectangular metal sheets are parallel to the common sides of the first metal grating 3 and the second metal grating 4.

[0062] More specifically, the projection areas of the first metal grating 3 and the second metal grating 4 are larger than the area of ​​the dielectric plate 6 , and the lengths of the long sides of the first metal grating 3 and the second metal grating 4 are equal to the length of the dielectric plate 6 .

[0063] The metal back plate 1 acts as a floor and produces directional radiation characteristics through reflection.

[0064] The size of the dielectric plate 6 is equal to that of the metal back plate 1, and the vertical distance from the dielectric plate 6 to the common edge of the first metal grating 3 and the second metal grating 4 is greater than half of the vacuum wavelength corresponding to the operating frequency of the high front-to-back ratio directional antenna.

[0065] Example 2

[0066] In this embodiment, a high front-to-back ratio directional antenna includes: a metal back plate 1, a metal radiation patch 2, a first metal grating 3, a second metal grating 4, a metal feeding microstrip line 5, a dielectric plate 6, a feeding connector 7, a first plastic plate 10, and a second plastic plate 11;

[0067] The metal back plate 1 is arranged at the bottom of the dielectric plate 6; the metal radiation patch 2 is arranged at the top of the dielectric plate 6; the metal feeding microstrip line 5 is arranged at the top of the dielectric plate 6 and connected to the metal radiation patch 2; the feeding connector 7 is arranged at the bottom of the metal back plate and passes through the dielectric plate 6 to connect to the metal feeding microstrip line 5;

[0068] The first plastic plate 10 is connected to the front side of the dielectric plate 6; the second plastic plate 11 is connected to the rear side of the dielectric plate 6; the tops of the first plastic plate 10 and the second plastic plate 11 are both provided with a triangular structure;

[0069] The long side of the first metal grating 3 is connected to the long side of the second metal grating 4, and the first metal grating 3 and the second metal grating 4 form an angle, and the angle is equal to the vertex angle of the triangular structure;

[0070] One end of the first metal grating 3 is arranged on an inclined surface of the triangular structure of the first plastic plate 10, and the other end of the first metal grating 3 is arranged on an inclined surface of the triangular structure of the second plastic plate 11; one end of the second metal grating 4 is arranged on another inclined surface of the triangular structure of the first plastic plate 10, and the other end of the second metal grating 4 is arranged on another inclined surface of the triangular structure of the second plastic plate 11; the angle is downward.

[0071] In this embodiment, the angle is 146°; the thickness of the first plastic plate 10 and the second plastic plate 11 is 0.8 m.

[0072] More specifically, the metal radiation patch 2 is a rectangular patch antenna;

[0073] The wide side of the rectangular patch antenna is vertical to the common side space of the first metal grating 3 and the second metal grating 4 .

[0074] More specifically, the electric field polarization direction of the rectangular patch antenna is perpendicular to the common edge of the first metal grating 3 and the second metal grating 4 .

[0075] More specifically, the feed connector 7 includes a central feed pin 12 and an outer conductor 13;

[0076] The central feeding needle 12 is connected to the metal feeding microstrip line 5 ; the outer conductor 13 is connected to the metal back plate 1 .

[0077] In this embodiment, the first metal grating 3 and the second metal grating 4 have the same size; the first metal grating 3 and the second metal grating 4 are planar structures, each comprising a plurality of rectangular metal sheets arranged at equal intervals; and the plurality of rectangular metal sheets have the same size, and the width of each rectangular metal sheet is greater than the spacing between adjacent rectangular metal sheets; the spacing between the rectangular metal sheets of the first metal grating 3 is equal to the spacing between the rectangular metal sheets of the second metal grating 4; the long sides of the rectangular metal sheets are parallel to the common sides of the first metal grating 3 and the second metal grating 4.

[0078] More specifically, the projection areas of the first metal grating 3 and the second metal grating 4 are larger than the area of ​​the dielectric plate 6 , and the lengths of the first metal grating 3 and the second metal grating 4 are the same as those of the dielectric plate 6 .

[0079] The metal back plate 1 acts as a floor and produces directional radiation characteristics through reflection.

[0080] In this embodiment, the size of the dielectric plate 6 is equal to that of the metal back plate 1, and the vertical distance from the dielectric plate 6 to the first metal grating 3 and the second metal grating 4 is equal to two-thirds of the vacuum wavelength corresponding to the working frequency of the high front-to-back ratio directional antenna;

[0081] Example 3

[0082] In this embodiment, if Figure 3 As shown, compared with the plane radiation pattern perpendicular to the common edge, the dotted line corresponds to the original radiation direction of the antenna source without using a grating, the dotted line corresponds to the radiation direction using a horizontal metal grating, and the corresponding radiation direction is the high front-to-back ratio directional antenna used in the present invention; compared with the antenna without a grating, the radiation direction of the front end of the present invention is farther, and the radiation direction of the back lobe is small; compared with the antenna using parallel gratings, the radiation direction of the front end of the present invention is not much different, and the radiation direction of the back lobe is small; it can be seen that the angle structure formed by the first metal grating 3 and the second metal grating 4 suppresses the backward radiation of electromagnetic waves, reduces the antenna back lobe, and improves the antenna front-to-back ratio; the high front-to-back ratio directional antenna has a strong anti-interference ability in the back lobe direction, and directs the back lobe direction toward the interference source, thereby reducing the interference received or the interference to the backward direction.

[0083] Obviously, the above embodiments of the present invention are only examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A directional antenna with high front-to-back ratio, It is characterized in that include: A metal back plate (1), a metal radiation patch (2), a first metal grating (3), a second metal grating (4), a metal feeding microstrip line (5), a dielectric plate (6), a feeding connector (7), a first plastic plate (10), and a second plastic plate (11); The metal back plate (1) is arranged at the bottom of the dielectric plate (6); the metal radiation patch (2) is arranged at the top of the dielectric plate (6); the metal feeding microstrip line (5) is arranged at the top of the dielectric plate (6) and connected to the metal radiation patch (2); the feeding connector (7) is arranged at the bottom of the metal back plate and passes through the dielectric plate (6) to be connected to the metal feeding microstrip line (5); The first plastic plate (10) is connected to the front side of the dielectric plate (6); the second plastic plate (11) is connected to the rear side of the dielectric plate (6); the tops of the first plastic plate (10) and the second plastic plate (11) are both provided with a triangular structure; The long side of the first metal grating (3) and the long side of the second metal grating (4) are connected, and the first metal grating (3) and the second metal grating (4) form an angle, and the angle is equal to the vertex angle of the triangular structure; One end of the first metal grating (3) is arranged on an inclined surface of the triangular structure of the first plastic plate (10), and the other end of the first metal grating (3) is arranged on an inclined surface of the triangular structure of the second plastic plate (11); one end of the second metal grating (4) is arranged on another inclined surface of the triangular structure of the first plastic plate (10), and the other end of the second metal grating (4) is arranged on another inclined surface of the triangular structure of the second plastic plate (11); the angle is downward.

2. A directional antenna with high front-to-back ratio according to claim 1, It is characterized in that It also includes a first short-circuit metal sheet (8) and a second short-circuit metal sheet (9); The length of the dielectric plate (6) is the same as the length of the metal radiation patch (2); The first short-circuit metal sheet (8) is arranged between the first plastic plate (10) and the dielectric plate; the second short-circuit metal sheet (9) is arranged between the second plastic plate (11) and the dielectric plate; A long side of the first short-circuit metal sheet (8) is connected to a wide side of the metal radiation patch (2); The other long side of the first short-circuit metal sheet (8) is connected to a wide side of the metal back plate (1); One long side of the second short-circuit metal sheet (9) is connected to the other wide side of the metal radiation patch (2); The other long side of the second short-circuit metal sheet (9) is connected to the other wide side of the metal back plate (1).

3. A directional antenna with high front-to-back ratio according to claim 2, It is characterized in that The metal radiation patch (2) is a rectangular patch antenna; The wide side of the rectangular patch antenna is vertical to the common side space of the first metal grating (3) and the second metal grating (4).

4. A directional antenna with high front-to-back ratio according to claim 3, It is characterized in that The length of the first short-circuit metal sheet (8) and the second short-circuit metal sheet (9) is equal to the width of the rectangular patch antenna, and the width of the first short-circuit metal sheet (8) and the second short-circuit metal sheet (9) is equal to the height of the dielectric plate (6).

5. A directional antenna with high front-to-back ratio according to claim 3, It is characterized in that The electric field polarization direction of the rectangular patch antenna is perpendicular to the common edge of the first metal grating (3) and the second metal grating (4).

6. A directional antenna with high front-to-back ratio according to claim 1, It is characterized in that The feed connector (7) comprises a central feed pin (12) and an outer conductor (13); The central feeding needle (12) is connected to the metal feeding microstrip line (5); and the outer conductor (13) is connected to the metal back plate (1).

7. The directional antenna with high front-to-back ratio according to claim 1, It is characterized in that The first metal grating (3) and the second metal grating (4) have the same size; the first metal grating (3) and the second metal grating (4) are planar structures, each comprising a plurality of rectangular metal sheets arranged at equal intervals; the plurality of rectangular metal sheets have the same size, and the width of each rectangular metal sheet is greater than the spacing between adjacent rectangular metal sheets; the spacing between the rectangular metal sheets of the first metal grating (3) is equal to the spacing between the rectangular metal sheets of the second metal grating (4); and the long sides of the rectangular metal sheets are parallel to the common sides of the first metal grating (3) and the second metal grating (4).

8. A directional antenna with high front-to-back ratio according to claim 7, It is characterized in that The projection areas of the first metal grating (3) and the second metal grating (4) are larger than the area of ​​the dielectric plate (6), and the lengths of the long sides of the first metal grating (3) and the second metal grating (4) are equal to the length of the dielectric plate (6).

9. The directional antenna with high front-to-back ratio according to claim 1, It is characterized in that The metal back plate (1) acts as a floor and generates directional radiation characteristics through reflection.

10. The directional antenna with high front-to-back ratio according to claim 1, It is characterized in that The size of the dielectric plate (6) is equal to that of the metal back plate (1), and the vertical distance from the dielectric plate (6) to the common edge of the first metal grating (3) and the second metal grating (4) is greater than half of the vacuum wavelength corresponding to the operating frequency of the high front-to-back ratio directional antenna.

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