Broadband beam-scanning conformal array antenna based on low-profile frequency selective surface

Abstract

The present invention discloses a broadband beam-scanning conformal array antenna based on a low-profile frequency selective surface. The antenna comprises a dipole feed, a semi-cylindrical bandpass array antenna, and a semi-cylindrical band-rejection array antenna. The semi-cylindrical bandpass array antenna and the semi-cylindrical band-rejection array antenna are connected to form a hollow three-dimensional cylindrical array antenna. The dipole feed is located at the axis of the three-dimensional cylindrical array antenna. The semi-cylindrical bandpass array antenna is used to transmit electromagnetic waves; the semi-cylindrical band-rejection array antenna is used to reflect electromagnetic waves. By mechanically rotating the three-dimensional cylindrical array antenna, the spatial positions of the semi-cylindrical bandpass array antenna and the semi-cylindrical band-rejection array antenna in the three-dimensional cylindrical array antenna are changed to obtain different beam directions, thereby achieving 360-degree beam scanning in the horizontal plane. The array antenna has the advantages of simple structure, low cost, low loss, and good broadband performance.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to a broadband beam scanning conformal array antenna based on a low-profile frequency selective surface. Background Art

[0002] In existing technology, there are two main types of scanning antenna arrays: one is the planar scanning antenna array, which has been widely used due to its thin profile, small size, light weight, and easy integration. However, its beam scanning range is limited, with a maximum scanning angle of approximately 120°. Furthermore, the gain decreases sharply as the scanning angle increases during scanning, making it impossible to achieve wider scanning ranges. The other is the conformal scanning antenna array, in which the antenna elements are no longer distributed on the same plane but conformally conform to the surface of a three-dimensional carrier. This allows the beam scanning range to easily cover an area greater than a hemisphere, and the antenna gain fluctuates less during scanning. However, conformal scanning antenna arrays are typically bulky and have a high overall profile, making it a major challenge to achieve a wide angular scanning range while maintaining the lowest possible profile.

[0003] A frequency selective surface (FSS) is a technology used to modulate the properties of electromagnetic waves. It consists of a single-layer or multi-layer two-dimensional periodic array structure formed by periodically arranged conductive patch units, or slotted units on the conductive patch. FSSs exhibit selective transmittance or reflectivity. When the resonant units of a FSS resonate at a certain frequency, they can almost completely transmit electromagnetic waves at that frequency, a bandpass FSS, or almost completely reflect electromagnetic waves, a bandstop FSS. Its unique properties have been widely used in various military and civilian applications, covering most of the electromagnetic spectrum, including microwaves, millimeter waves, and infrared bands.

[0004] The current optimal solution for achieving ultra-large-scale spatial scanning is to use conformal antenna arrays. However, spherical conformal antenna arrays suffer from the significant disadvantage of being too high in profile, resulting in excessive volume. This, in turn, presents challenges such as high carrier space requirements, complex structures, and difficult assembly. Summary of the Invention

[0005] The technical problem to be solved by the present invention is how to provide a broadband beam scanning conformal array antenna with simple structure, low cost, low loss and good broadband performance.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is: a broadband beam scanning conformal array antenna based on a low-profile frequency selective surface, characterized in that: it includes a dipole feed, a semi-cylindrical bandpass array antenna, and a semi-cylindrical band-rejection array antenna, the semi-cylindrical bandpass array antenna and the semi-cylindrical band-rejection array antenna being connected to form a hollow three-dimensional cylindrical array antenna, the dipole feed being located at the axis center of the three-dimensional cylindrical array antenna, the dipole feed being used to transmit electromagnetic waves, the semi-cylindrical bandpass array antenna being used to transmit electromagnetic waves, and when it resonates at a certain operating frequency, it can allow electromagnetic waves of this frequency to pass through; the semi-cylindrical band-rejection array antenna being used to reflect electromagnetic waves, and when it resonates at a certain operating frequency, it can cause electromagnetic waves of this frequency to be reflected back on its surface; by mechanically rotating the three-dimensional cylindrical array antenna, the spatial positions of the semi-cylindrical bandpass array antenna and the semi-cylindrical band-rejection array antenna in the three-dimensional cylindrical array antenna are changed to obtain different beam directions, thereby achieving 360° beam scanning in the horizontal plane.

[0007] A further technical solution is that: the semi-cylindrical bandpass array antenna includes a plurality of bandpass array units, and the bandpass array unit includes a first dielectric layer, a first square metal patch is formed on the upper surface of the first dielectric layer, a second dielectric layer is provided on the lower side of the first dielectric layer, a first square metal ring and a second square metal patch are formed between the first dielectric layer and the second dielectric layer, the second square metal patch is located in the first square metal ring and the two do not contact each other, and a third square metal patch is formed on the lower surface of the second dielectric layer.

[0008] A further technical solution is that the outer ring of the first square metal ring overlaps with the outer ring of the first dielectric layer, and the first square metal patch, the second square metal patch and the third square metal patch overlap in the vertical projection direction.

[0009] A further technical solution is that: the semi-cylindrical band-stop array antenna includes a plurality of band-stop array units, the band-stop array unit includes a third dielectric layer, a fourth square metal patch is formed on the upper surface of the third dielectric layer, a fourth dielectric layer is provided on the lower side of the third dielectric layer, a second square metal ring and a fifth square metal patch are formed between the third dielectric layer and the fourth dielectric layer, the fifth square metal patch is located in the second square metal ring and the two are connected together by a direction bar, and a sixth square metal patch is formed on the lower surface of the fourth dielectric layer.

[0010] A further technical solution is that: four direction bars are provided, which are respectively connected to the four sides of the fifth square metal patch and the four inner sides of the second square metal ring.

[0011] A further technical solution is that the outer ring of the second square metal ring overlaps with the outer ring of the third dielectric layer, and the fourth square metal patch, the fifth square metal patch and the sixth square metal patch overlap in the vertical projection direction.

[0012] The beneficial effects of adopting the above technical solution are: the bandpass array unit and the bandstop array unit in the scanning conformal array antenna described in the present invention have the advantages of light weight, low profile and simple structure, and the processing cost and difficulty of the array antenna are also greatly reduced; the bandpass array unit and the bandstop array unit structure are symmetrical about the origin center, which can realize dual-polarization characteristics and have low loss characteristics, and due to their frequency selective surface structure, have good broadband performance; compared with the electrically controlled beam scanning antenna, the present invention only needs to obtain different beam directions through mechanical rotation, and realize 360° beam scanning in the horizontal plane, which has the advantages of low cost and simple structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0014] Figure 1 is a side schematic diagram of a bandpass array unit in an embodiment of the present invention;

[0015] Figure 2 1 is a side view of a band-stop array unit according to an embodiment of the present invention;

[0016] Figure 3 Schematic top view of a first square metal ring and a second square metal patch in a bandpass array unit according to an embodiment of the present invention;

[0017] Figure 4 Schematic top view of the second square metal ring and the fifth square metal patch in the band-stop array unit according to an embodiment of the present invention;

[0018] Figure 5 is an S-parameter diagram of a bandpass array unit in an embodiment of the present invention;

[0019] Figure 6 is an S-parameter diagram of a band-stop array unit according to an embodiment of the present invention;

[0020] Figure 7 A feed source for the conformal array antenna described in an embodiment of the present invention;

[0021] Figure 8 Schematic diagram of the structure of the conformal array antenna of the present invention;

[0022] Figure 9 The normalized radiation patterns of the conformal array antenna of the present invention when mechanically rotated at different angles;

[0023] Among them: 1. First square metal patch; 2. First dielectric layer; 4. Second dielectric layer; 5. Third square metal patch; 6. Fourth square metal patch; 7. Third dielectric layer; 9. Fourth dielectric layer; 10. Sixth square metal patch; 11. First square metal ring; 12. Second square metal patch; 13. Second square metal ring; 14. Fifth square metal patch; 15. Directional bar; 16. Dipole feed; 17. Broadband beam scanning conformal array antenna. DETAILED DESCRIPTION

[0024] The following is a clear and complete description of the technical solutions in the embodiments of the present invention, in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts are within the scope of protection of the present invention.

[0025] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0026] like Figure 8 As shown, an embodiment of the present invention discloses a broadband beam scanning conformal array antenna based on a low-profile frequency selective surface, including a dipole feed 16, a semi-cylindrical bandpass array antenna, and a semi-cylindrical band-rejection array antenna. The semi-cylindrical bandpass array antenna and the semi-cylindrical band-rejection array antenna are connected to form a hollow three-dimensional cylindrical array antenna. The dipole feed 16 is located at the axis of the three-dimensional cylindrical array antenna. The dipole feed 16 is used to transmit electromagnetic waves. The semi-cylindrical bandpass array antenna is used to transmit electromagnetic waves. When it resonates at a certain operating frequency, it can allow electromagnetic waves of this frequency to pass through; the semi-cylindrical band-rejection array antenna is used to reflect electromagnetic waves. When it resonates at a certain operating frequency, it can cause electromagnetic waves of this frequency to be reflected back from its surface; by mechanically rotating the three-dimensional cylindrical array antenna, the spatial positions of the semi-cylindrical bandpass array antenna and the semi-cylindrical band-rejection array antenna in the three-dimensional cylindrical array antenna are changed to obtain different beam directions, thereby achieving 360° beam scanning in the horizontal plane.

[0027] The dipole feed 16 is placed at the center of the three-dimensional cylindrical array antenna, and the feed is used to transmit electromagnetic waves. The semi-cylindrical bandpass array antenna unit is used to transmit electromagnetic waves. When it resonates at a certain operating frequency, it can allow electromagnetic waves of this frequency to pass through the bandpass array antenna unit. The semi-cylindrical band-rejection array antenna unit is used to reflect electromagnetic waves. When it resonates at a certain operating frequency, unlike the bandpass array antenna unit, it can reflect electromagnetic waves of this frequency back from the band-rejection array antenna unit.

[0028] The bandpass and bandstop array elements are symmetrical about the origin, with identical performance in the x and y directions on the xoy horizontal plane, and dual-polarization characteristics. The array antenna operates at 10 GHz, with a unit matrix N×M of 10×10. The antenna diameter is less than 80 mm and the height is less than 200 mm. Due to the array's scalability, this design can also be extended to other antenna aperture sizes and frequency bands.

[0029] For further information, see Figure 1 and Figure 3 The semi-cylindrical bandpass array antenna includes 5×10 bandpass array elements. The semi-cylindrical bandpass array antenna comprises several bandpass array elements, each comprising a first dielectric layer 2. A first square metal patch 1 is formed on the upper surface of the first dielectric layer 2. A second dielectric layer 4 is disposed below the first dielectric layer 2. A first square metal ring 11 and a second square metal patch 12 are formed between the first and second dielectric layers 2 and 4. The second square metal patch 12 is located within the first square metal ring 11 and does not contact the second square metal patch 12. A third rectangular metal patch 5 is formed on the lower surface of the second dielectric layer 4. The outer ring of the first square metal ring 11 overlaps with the outer ring of the first dielectric layer 2. The first square metal patch 1, the second square metal patch 12, and the third rectangular metal patch 5 overlap in the vertical projection direction.

[0030] The first square metal patch 1, the first square metal ring 11, the second square metal patch 12 and the third square metal patch 5 of the proposed bandpass array unit are placed horizontally along the xoy plane. The bandpass array unit structure is symmetrical about the origin and presents a three-dimensional structure.

[0031] In this example, the height of the dielectric layer of the bandpass array unit can be very thin or even non-existent, but considering that a dielectric plate with a certain hardness is required for support, the thickness of the plate is selected to be 0.05 wavelengths, that is, h1 = 2 mm; the dielectric layer material of the bandpass array unit is Rogers Ro3003, with a relative dielectric constant of 3.0; in order to make the bandpass array unit transmit electromagnetic waves, the first square metal ring 11 is not connected to the second square metal patch 12, and the width of the first square metal ring 11 is L 13=10mm, the width of the second square metal patch 12 is L 12 = 6mm; the first square metal patch 1, the second square metal patch 12 and the third square metal patch 5 of the bandpass array unit are equal in cross-sectional area along the xoy plane and have a width of L 11 =6mm;

[0032] For further information, see Figure 2 and Figure 4 The semi-cylindrical band-stop array antenna is composed of 5×10 band-stop array units, which include several band-stop array units. The band-stop array unit includes a third dielectric layer 7, a fourth square metal patch 6 is formed on the upper surface of the third dielectric layer 7, a fourth dielectric layer 9 is provided on the lower side of the third dielectric layer 7, a second square metal ring 13 and a fifth square metal patch 14 are formed between the third dielectric layer 7 and the fourth dielectric layer 9, the fifth square metal patch 14 is located in the second square metal ring 13 and the two are connected together by a direction bar 15, and a sixth square metal patch 10 is formed on the lower surface of the fourth dielectric layer 9.

[0033] The fourth square metal patch 6, second square metal ring 13, fifth square metal patch 14, directional bar 15, and sixth square metal patch 10 of the proposed band-stop array unit are horizontally arranged along the xoy plane. The band-stop array unit structure is symmetrical about the origin and presents a three-dimensional structure. Furthermore, four directional bars 15 are provided, respectively connected to the four edges of the fifth square metal patch 14 and the four inner edges of the second square metal ring 13. Furthermore, the outer ring of the second square metal ring 13 overlaps with the outer ring of the third dielectric layer 7, and the fourth square metal patch 6, the fifth square metal patch 14, and the sixth square metal patch 10 overlap in the vertical projection direction.

[0034] In the example, the dielectric layer height and material of the band-stop array unit are the same as those of the band-pass array unit, which has the advantages of simple design and simple array antenna processing. In order to make the band-stop array unit reflect electromagnetic waves, the second square metal ring 13 and the fifth square metal patch 14 are connected by a four-channel direction bar 15. The length of the direction bar 15 is L3 = 1mm, the width is W3 = 1mm, and the width of the second square metal ring 13 is L 23 =10mm, the width of the fifth square metal patch 14 is L 22 =6mm;

[0035] Figure 5This is the S-parameter graph of the bandpass array unit when the operating frequency is 10.0 GHz. In the frequency range of 8 GHz to 12 GHz, the unit has a maximum transmission amplitude loss of 0.869 dB, which is relatively small. It can be seen from the graph that the bandpass array unit has good broadband performance.

[0036] Figure 6 This is the S-parameter graph of the bandpass array unit when the band-stop array unit operates at a frequency of 10.0 GHz. In the frequency range of 8 GHz to 12 GHz, the unit has a maximum reflection amplitude loss of 1.525 dB, indicating that the reflection amplitude loss of the unit is relatively small. The graph shows that the bandpass array unit has good broadband performance.

[0037] Figure 7 A dipole feed source (16) of the broadband beam scanning conformal array antenna of the present invention is located at the center of the three-dimensional cylindrical array antenna and is used to transmit electromagnetic waves;

[0038] See Figure 8 , a semi-cylindrical bandpass array antenna and a semi-cylindrical band-rejection array antenna are sequentially connected along a certain curvature radius to form a cylindrical broadband beam scanning conformal array antenna 17; compared with the electrically controlled beam scanning antenna, the broadband beam scanning conformal array antenna with a low-profile frequency selective surface of the present invention only needs to mechanically rotate to change the spatial position of the bandpass array antenna and the band-rejection array antenna in the array antenna to obtain different beam directions, thereby realizing 360° beam scanning in the horizontal plane;

[0039] Figure 9 The figure shows the normalized radiation pattern of the broadband beam-scanning conformal array antenna with a low-profile frequency selective surface of the present invention at different mechanical rotation angles when the operating frequency is 10.0 GHz. As can be seen from the figure, the array antenna can achieve 360° beam scanning in the horizontal plane.

[0040] In summary, the array antenna described in the embodiment of the present invention has the following advantages:

[0041] (1) The bandpass array unit and the bandstop array unit of the present invention have the advantages of light weight, low profile and simple structure, and the processing cost and difficulty of the array antenna are greatly reduced;

[0042] (2) The bandpass array unit and the bandstop array unit of the present invention are symmetrical about the origin, can achieve dual-polarization characteristics, and have low loss characteristics. Due to their frequency selective surface structure, they have good broadband performance.

[0043] (3) Compared with the electrically controlled beam scanning antenna, the broadband beam scanning conformal array antenna based on the low-profile frequency selective surface of the present invention can obtain different beam directions only through mechanical rotation, and realize 360° beam scanning in the horizontal plane, which has the advantages of low cost and simple structure.

Claims

1. A broadband beam-scanning conformal array antenna based on a low-profile frequency selective surface, characterized by: The invention comprises a dipole feed source (16), a semi-cylindrical bandpass array antenna, and a semi-cylindrical band-stop array antenna. The semi-cylindrical bandpass array antenna and the semi-cylindrical band-stop array antenna are connected to form a hollow three-dimensional cylindrical array antenna. The dipole feed source (16) is located at the axis center position of the three-dimensional cylindrical array antenna. The dipole feed source (16) is used to transmit electromagnetic waves. The semi-cylindrical bandpass array antenna is used to transmit electromagnetic waves. When it resonates at a certain working frequency, it can allow electromagnetic waves of this frequency to pass through. The semi-cylindrical band-stop array antenna is used to reflect electromagnetic waves. When it resonates at a certain working frequency, it can allow electromagnetic waves of this frequency to be reflected back on its surface. By mechanically rotating the three-dimensional cylindrical array antenna, the spatial positions of the semi-cylindrical bandpass array antenna and the semi-cylindrical band-stop array antenna in the three-dimensional cylindrical array antenna are changed to obtain different beam directions, thereby realizing 360° beam scanning in the horizontal plane. The semi-cylindrical bandpass array antenna comprises a plurality of bandpass array units, wherein the bandpass array units comprise a first dielectric layer (2), a first square metal patch (1) is formed on the upper surface of the first dielectric layer (2), a second dielectric layer (4) is provided on the lower side of the first dielectric layer (2), a first square metal ring (11) and a second square metal patch (12) are formed between the first dielectric layer (2) and the second dielectric layer (4), the second square metal patch (12) is located inside the first square metal ring (11) and the two do not contact each other, and a third square metal patch (5) is formed on the lower surface of the second dielectric layer (4); the outer ring of the first square metal ring (11) and the outer ring of the first dielectric layer (2) overlap with each other, and the first square metal patch (1), the second square metal patch (12) and the third square metal patch (5) overlap in the upper and lower projection directions; The semi-cylindrical band-stop array antenna comprises a plurality of band-stop array units, wherein the band-stop array units comprise a third dielectric layer (7), a fourth square metal patch (6) is formed on the upper surface of the third dielectric layer (7), a fourth dielectric layer (9) is provided on the lower side of the third dielectric layer (7), a second square metal ring (13) and a fifth square metal patch (14) are formed between the third dielectric layer (7) and the fourth dielectric layer (9), the fifth square metal patch (14) is located in the second square metal ring (13) and the second square metal patch (14) is connected to the second square metal ring (13). The fourth dielectric layer (9) is connected to the fourth square metal patch (10) by the direction bars (15); the lower surface of the fourth dielectric layer (9) is formed with a sixth square metal patch (10); the direction bars (15) are provided with four strips, which are respectively connected to the four sides of the fifth square metal patch (14) and the four sides on the inner side of the second square metal ring (13); the outer ring of the second square metal ring (13) and the outer ring of the third dielectric layer (7) are overlapped with each other, and the fourth square metal patch (6), the fifth square metal patch (14) and the sixth square metal patch (10) are overlapped in the upper and lower projection directions.

2. The broadband beam-scanning conformal array antenna based on a low-profile frequency selective surface according to claim 1, wherein: The thickness of the first dielectric layer (2) and the second dielectric layer (4) is h1=2 mm, the relative dielectric constant is 3.0, and the side length of the first square metal patch (1) is L 11 =6mm; the side length L of the first square metal ring (11) 13 =10mm.

3. The broadband beam scanning conformal array antenna based on a low-profile frequency selective surface according to claim 1, wherein: The thickness of the third dielectric layer (7) and the fourth dielectric layer (9) is h1=2 mm, the relative dielectric constant is 3.0, and the side length of the fourth square metal patch (6) is L 21 =6mm; the side length L of the second square metal ring (13) 23 =10mm, the length of the direction strip (15) is L3=1mm, and the width is W3=1mm.

4. The broadband beam-scanning conformal array antenna based on a low-profile frequency selective surface according to claim 1, wherein: The bandpass array unit operates in the frequency range of 8 GHz to 12 GHz, and the maximum transmission amplitude loss is 0.869 dB.

5. The broadband beam scanning conformal array antenna based on a low-profile frequency selective surface according to claim 1, wherein: The band-stop array unit operates in the frequency range of 8 GHz to 12 GHz, and the maximum reflection amplitude loss is 1.525 dB.

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