Grounded subreflector back cavity antenna

Abstract

The application provides a ground type secondary-reflector back cavity antenna, which comprises a reflecting bottom plate, a secondary-reflector plate, a radiation unit, a metal surrounding frame and four ground extension structures, the secondary-reflector plate is arranged opposite to and parallel to the reflecting bottom plate, the radiation unit is arranged between the reflecting bottom plate and the secondary-reflector plate, the metal surrounding frame surrounds the edge of the reflecting bottom plate and forms a radiation cavity together with the reflecting bottom plate, the four ground extension structures are arranged at intervals along the periphery of the secondary-reflector plate, one end of each of the four ground extension structures is connected to different positions of the edge of the secondary-reflector plate, and the other end of each of the four ground extension structures is connected to the surface of the reflecting bottom plate on the side facing the secondary-reflector plate; the ground extension structures arranged on the periphery of the secondary-reflector plate divide the main radiation cavity into four secondary radiation cavities, realize uniform distribution of electric field, change the cross current distribution introduced by the metal back cavity, improve the matching characteristics and cross polarization characteristics of the radiation unit, and improve the antenna gain and bandwidth.

Description

Technical Field

[0001] This application relates to the field of displays, and in particular to a grounded sub-reflector cavity antenna. Background Technology

[0002] With the rapid development of mobile communication technology, base station antennas, as a key component of wireless communication systems, directly affect the coverage and communication quality of the entire system. In base station antenna systems, to expand coverage and improve signal quality, antenna elements with high gain and narrow beam characteristics are typically required. Cavity-backed antennas and short backfire antennas, as high-gain antenna elements, have received widespread attention.

[0003] Cavity antennas, by constructing a resonant cavity around the radiating element with a metal frame and a reflective base plate, can effectively suppress back radiation and improve gain. Short backfire antennas, based on the cavity structure, add a secondary reflector above the radiating element. By utilizing the multiple reflections and diffractions of electromagnetic waves between the secondary reflector and the reflective base plate, the radiated waves are superimposed in phase, thereby achieving even higher gain.

[0004] Since no grounding structure is set on the four edges of the secondary reflector, the edges of the secondary reflector are open circuits, resulting in a phase difference between the secondary radiation at the edge of the secondary reflector and the original radiation of the radiating element. This causes the far-field radiated waves to not be effectively superimposed in phase, resulting in reduced antenna gain and narrower operating bandwidth. Summary of the Invention

[0005] This application provides a grounded sub-reflector cavity antenna to solve the technical problems of low gain and narrow operating bandwidth of existing antennas.

[0006] To solve the above problems, the technical solution provided in this application is as follows: This application provides a grounded sub-reflector cavity antenna, which includes: Reflective base plate; The secondary reflector is arranged opposite to and parallel to the reflector base plate; A radiating element is disposed between the reflective base plate and the secondary reflective plate; A metal frame surrounds and connects to the edge of the reflective base plate, and together with the reflective base plate, forms a radiation cavity; and The four grounding extension structures are arranged at intervals along the periphery of the secondary reflector; One end of each of the four grounding extension structures is connected to a different position on the edge of the secondary reflector, and the other end of each of the four grounding extension structures is connected to the surface of the reflector base plate facing the secondary reflector.

[0007] Optionally, the grounding extension structure includes a first extension and a second extension connected to each other, wherein the end of the first extension away from the second extension is connected to an edge of the secondary reflector, and the end of the second extension away from the first extension is electrically connected to the reflector base plate. The first extension is arranged parallel to the reflective base plate.

[0008] Optionally, the first extension and the second extension are arranged vertically.

[0009] Optionally, the end of the first extension away from the second extension is connected to the region where the center of one edge of the secondary reflector is located; Alternatively, the end of the first extension away from the second extension is connected to the region where the connection point of two adjacent edges of the secondary reflector is located. Alternatively, the four grounding extension structures are respectively connected to the four edges of the secondary reflector, and the connection points of the four grounding extension structures are offset clockwise or counterclockwise relative to the center of the corresponding edge. The length of the connecting line between the two oppositely arranged first extensions is equal to the length of the connecting line between the two oppositely arranged first extensions.

[0010] Optionally, the line connecting the center of the secondary reflector and the center of the reflective base plate is perpendicular to the reflective base plate.

[0011] Optionally, the outer contour of the secondary reflector has a centrally symmetrical pattern.

[0012] Optionally, the width of the grounding extension structure ranges from 0.01λ to 0.2λ; or / and The length of the secondary reflector ranges from 0.3λ to 0.6λ, and the width of the secondary reflector ranges from 0.3λ to 0.6λ; or / and The length of the reflective base plate ranges from 1λ to 1.8λ, and the width of the reflective base plate ranges from 1λ to 1.8λ; or / and The height of the metal frame ranges from 0.3λ to 0.6λ; or / and The distance between the secondary reflector and the metal frame ranges from 0.3λ to 0.6λ. Wherein, λ is the free space wavelength corresponding to the center frequency of the operating frequency band; Optionally, in the direction from the reflective base plate to the secondary reflective plate, the distance between the secondary reflective plate and the reflective base plate is less than or equal to the height of the metal frame.

[0013] Optionally, the radiating element includes two orthogonally arranged symmetrical dipoles, the polarization directions of the two symmetrical dipoles being positive 45 degrees and negative 45 degrees, respectively, or the polarization directions of the two symmetrical dipoles being 0 degrees and 90 degrees, respectively; Alternatively, the radiating element may include a patch antenna and a parasitic patch, wherein the patch antenna is attached to the reflective substrate and the parasitic patch is disposed between the patch antenna and the secondary reflector.

[0014] Optionally, the distance between the center of the radiating element and the center of the reflective substrate is in the range of 0 to 0.1λ.

[0015] Beneficial effects: This application divides the main radiation cavity into four secondary radiation cavities by setting a ground extension structure around the secondary reflector, thereby achieving a uniform distribution of the electric field, changing the cross current distribution introduced by the metal back cavity, improving the matching characteristics and cross polarization characteristics of the radiation element, and enhancing the antenna gain and bandwidth. Attached Figure Description

[0016] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0017] Figure 1 This is a first structural diagram of a ±45-degree polarized high-gain broadband cavity antenna according to an embodiment of this application; Figure 2 for Figure 1 Structural diagram of the central metal frame; Figure 3 for Figure 1 Structural diagram of the secondary reflector and grounding extension structure; Figure 4 for Figure 1 The front view; Figure 5 This is a second structural diagram of the ±45-degree polarized high-gain broadband cavity antenna according to an embodiment of this application; Figure 6 This is a third structural diagram of the ±45-degree polarized high-gain broadband cavity antenna according to an embodiment of this application.

[0018] Figure 7 The figure shows the S-parameter simulation results of the high-gain broadband cavity-back antenna according to an embodiment of this application. Figure 8 The above is a simulation result of the radiation pattern of the high-gain broadband cavity antenna according to an embodiment of this application. Figure 9 This is a first structural diagram of a 0- or 90-degree polarized high-gain broadband cavity antenna according to an embodiment of this application; Figure 10 for Figure 9 The front view of; Figure 11 This is a second structural diagram of the 0- and 90-degree polarized high-gain broadband cavity antenna according to an embodiment of this application; Figure 12 This is a fourth structural diagram of the ±45-degree polarized high-gain broadband cavity antenna according to an embodiment of this application; Figure 13 This is a fifth structural diagram of the ±45-degree polarized high-gain broadband cavity antenna according to an embodiment of this application; Figure 14 This is the sixth structural diagram of the ±45-degree polarized high-gain broadband cavity antenna according to the embodiments of this application; Figure 15 for Figure 14 The front view; Figure 16 This is an antenna array model according to an embodiment of this application. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0020] In scenarios involving 33-degree split antennas and 33-degree high-speed rail coverage, antennas are required to have a narrow beamwidth of approximately 33 degrees in either the horizontal or vertical plane to achieve precise beam control and optimized coverage. Traditionally, to achieve narrow beam and high gain, array antenna schemes are typically used, which involve assembling multiple antenna elements in conjunction with a feeding network. However, array antenna schemes suffer from problems such as complex feeding networks, high costs, and difficult installation and maintenance. Consequently, cavity-backed antennas and short backfire antennas have gained widespread attention as high-gain antenna elements.

[0021] The current antenna's secondary reflector has no grounding structure on any of its four edges, and the edges of the secondary reflector are open circuits. This results in a phase difference between the secondary radiation from the edges of the secondary reflector and the original radiation from the radiating element, which prevents the far-field radiated waves from being effectively superimposed in phase, thus reducing the antenna gain and narrowing the operating bandwidth.

[0022] Please see Figures 1 to 16 This application provides a grounded secondary reflector cavity antenna 100, which includes a reflector base plate 10, a secondary reflector plate 20, a radiating element 30, a metal frame 40, and four grounded extension structures 50.

[0023] In this embodiment, the secondary reflector 20 is arranged opposite to and parallel to the reflector base plate 10; the radiation unit 30 is disposed between the reflector base plate 10 and the secondary reflector 20; the metal frame 40 is connected around the edge of the reflector base plate 10 and forms a radiation cavity with the reflector base plate 10; the four grounding extension structures 50 are arranged at intervals along the periphery of the secondary reflector 20.

[0024] In this embodiment, one end of each of the four grounding extension structures 50 is connected to a different position on the edge of the secondary reflector 20, and the other end of each of the four grounding extension structures 50 is connected to the surface of the reflector base plate 10 facing the secondary reflector 20.

[0025] This application eliminates secondary radiation at the edge of the secondary reflector 20 by setting a ground extension structure 50 around the periphery of the secondary reflector 20, which changes the edge of the secondary reflector 20 from an open-circuit end to a short-circuit end. At the same time, it changes the current distribution pattern on the secondary reflector 20, improves the matching characteristics of the radiating element 30, and enhances the antenna gain and bandwidth.

[0026] It should be noted that the radiating element 30 of this application can also be referred to as an antenna element, a vibrator, a feed source, etc. The radiating element 30 is a unit that constitutes the basic structure of the antenna array. The radiating element 30 can effectively radiate or receive radio waves.

[0027] It should be noted that the reflector in this application (such as the reflective base plate 10, metal frame 40, and secondary reflector 20 mentioned in the embodiments of this application) can also be referred to as a base plate, antenna panel, metal reflective surface, etc. The reflector is used to improve the receiving sensitivity of the antenna signal, reflect and concentrate the antenna signal on the receiving point, thereby enhancing the antenna's receiving and transmitting capabilities. It also serves to block and shield the received signal from other radio waves from the rear (opposite direction).

[0028] It should be noted that the feed network of this application feeds signals to the radiating unit 30 with a certain amplitude and phase, or transmits received wireless signals to the signal processing unit of the base station with a certain amplitude and phase. The feed network is usually composed of controlled impedance transmission lines. In addition, the feed network may include phase shifters, and in some cases, the feed network may also include devices such as combiners and filters.

[0029] Please see Figures 1 to 5The secondary reflector has a secondary reflective surface opposite to the reflective substrate. This secondary reflective surface reflects a portion of the electromagnetic waves radiated upwards by the radiating element 30 back into the cavity, causing multiple reflections and superpositions of the electromagnetic waves within the cavity, thereby increasing gain and compressing beamwidth. The radiating element 30 is connected to an external radio frequency circuit via a coaxial feed line to achieve signal transmission and reception. The metal frame 40 and the reflective substrate 10 together constitute the main radiating cavity. The metal frame 40 limits the propagation range of the electromagnetic waves, creating a cavity resonance effect, thereby improving the antenna's directivity and gain. The reflective substrate 10, as the main reflective surface of the antenna, reflects electromagnetic waves to form directional radiation. Simultaneously, the secondary reflector 20 is electrically connected to the reflective substrate 10 via grounded extension structures 50 on both sides to form a stable cavity structure.

[0030] In this embodiment, the reflective base plate 10 can be a regular polygon, such as a rectangle or a square.

[0031] In this embodiment, the reflective base plate 10 can be a metal plate made of a metal material with good electrical conductivity, such as copper, aluminum or tin-plated steel plate.

[0032] In this embodiment, the length of the reflective base plate 10 can be from 1λ to 1.8λ, and the width of the reflective base plate 10 can be from 1λ to 1.8λ; for example, the length of the reflective base plate 10 can be 1.6λ, and the width can be 1.6λ.

[0033] It should be noted that λ in this application refers to the free space wavelength corresponding to the center frequency of the operating frequency band (2.6 GHz).

[0034] Please see Figures 1 to 5 The metal frame 40 can be formed by connecting four rectangular metal side plates end to end to form a rectangular frame structure. The four side plates are respectively perpendicularly connected to the four sides of the reflective base plate 10.

[0035] In this embodiment, the height of the metal frame 40 ranges from 0.3λ to 0.6λ, for example, the height of the metal frame 40 is 0.4λ.

[0036] In this embodiment, the metal frame 40 can be made of the same material as the reflective base plate 10, and the metal frame 40 and the reflective base plate 10 can be connected by integral molding or welding.

[0037] In this embodiment, the radiating element 30 can be any type of structure, including but not limited to patches, symmetrical arrays, and gaps.

[0038] Please see Figures 1 to 5The radiation unit 30 can be a dual-polarized radiation unit 30. For example, the radiation unit 30 includes two orthogonally arranged symmetrical oscillators with polarization directions of +45 degrees and -45 degrees, respectively, to achieve ±45-degree dual-polarized radiation. That is, the included angle between the two symmetrical oscillators and any edge of the secondary reflector 20 is 45 degrees.

[0039] In this embodiment, the distance between the orthographic projection of the center of the radiating unit 30 on the reflective base plate 10 and the center of the reflective base plate 10 is in the range of 0 to 0.1λ. For example, the distance between the orthographic projection of the center of the radiating unit 30 on the reflective base plate 10 and the center of the reflective base plate 10 in this application can be 0, which is equivalent to the center point of the radiating unit 30 coinciding with the center point of the reflective base plate 10.

[0040] In this embodiment, the outer contour of the secondary reflector 20 is a centrally symmetrical pattern. For example, the secondary reflector 20 can be a regular polygon or a circle. The regular polygon can be a rectangle, a square, etc.

[0041] Please see Figures 1 to 5 This application uses a square metal plate as an example to illustrate the secondary reflector 20, which is arranged opposite to and parallel to the reflective base plate 10.

[0042] In this embodiment, the length of the secondary reflector 20 ranges from 0.3λ to 1λ, and the width of the secondary reflector 20 ranges from 0.3λ to 1λ; for example, the length of the secondary reflector 20 is 0.8λ and the width is 0.8λ.

[0043] For example, participating Figure 4 The secondary reflector 20 is located at the center of the metal frame 40, and the secondary reflector 20 is square. Four grounding extension structures 50 extend outward along the center of the four sides of the secondary reflector 20 and are electrically connected to the reflector base plate 10.

[0044] In this embodiment, the radiation unit 30 is located at the center projection position of the secondary reflector 20, and the secondary reflector 20 of this application completely covers the radiation unit 30.

[0045] Please see Figures 1 to 5 The grounding extension structure 50 includes a first extension 501 and a second extension 502 connected to each other. The end of the first extension 501 away from the second extension 502 is connected to an edge of the secondary reflector 20. The end of the second extension 502 away from the first extension 501 is electrically connected to the reflector base plate 10. The first extension 501 is arranged parallel to the reflector base plate 10.

[0046] In this embodiment, the first extension 501 and the second extension 502 can be integrally formed, and the first extension 501 and the second extension 502 can be arranged at an angle. For example, the angle between the first extension 501 and the second extension 502 can be an obtuse angle, an acute angle, or a right angle. This application will describe the first extension 501 and the second extension 502 as being arranged vertically.

[0047] Please see Figures 1 to 5 The first extension 501, located away from the second extension 502, is connected to the region near the center of one edge of the secondary reflector 20; for example, when the secondary reflector 20 is square, it has four edges, and the first extension 501 of the grounding extension structure 50 is connected to the region near the center of one edge of the secondary reflector 20. In this embodiment, the length of the connecting line between the two oppositely arranged first extensions 501 is equal to the length of the connecting line between the other two oppositely arranged first extensions 501.

[0048] For example, when the secondary reflector 20 is square, the secondary reflector 20 has a first edge A1A2, a second edge A2A3, a third edge A3A4, and a fourth edge A4A1. The first edge A1A2 and the third edge A3A4 are arranged opposite to each other, and the second edge A2A3 and the fourth edge A4A1 are arranged opposite to each other. The four grounding extension structures 50 include a first extension structure 510, a second extension structure 520, a third extension structure 530, and a fourth extension structure 540. The first extension structure 510 is connected to the region where the center of the first edge A1A2 is located, the second extension structure 520 is connected to the region where the center of the second edge A2A3 is located, the third extension structure 530 is connected to the region where the center of the third edge A3A4 is located, and the fourth extension structure 540 is connected to the region where the center of the fourth edge A4A1 is located.

[0049] exist Figure 3 In the first extension structure 510 and the third extension structure 530 are arranged opposite to each other, and the connecting line between the first extension portion 501 of the first extension structure 510 and the first extension portion 501 of the third extension structure 530 is A1A3; the second extension structure 520 and the fourth extension structure 540 are arranged opposite to each other, and the connecting line between the first extension portion 501 of the second extension structure 520 and the first extension portion 501 of the fourth extension structure 540 is A2A4, that is, the lengths of the connecting lines A1A3 and A2A4 are equal.

[0050] In this embodiment, the line connecting the center of the secondary reflector 20 and the center of the reflective base plate 10 is perpendicular to the reflective base plate 10.

[0051] In this embodiment, the grounding extension structure 50 can be a metal strip structure and is rectangular. The width of the grounding extension structure 50 ranges from 0.01λ to 0.2λ. For example, the width of each grounding extension structure 50 can be 0.1λ and the longitudinal length can be 0.4λ (i.e., the length of the second extension 502).

[0052] In this embodiment, in the direction from the reflective base plate 10 to the secondary reflective plate 20, the distance between the secondary reflective plate 20 and the reflective base plate 10 is less than or equal to the height of the metal frame 40, which means that the secondary reflective plate 20 of this application is located in the cavity formed by the metal frame 40 and the reflective base plate 10; for example, the distance between the secondary reflective plate 20 and the reflective base plate 10 can be 0.4λ.

[0053] In this embodiment, the distance between the periphery of the secondary reflector 20 and the metal frame 40 ranges from 0.3λ to 0.6λ.

[0054] In the cavity antenna of this application, the radiating element 30 radiates electromagnetic waves in all directions. The electromagnetic waves radiated upward reach the secondary reflector 20 and are reflected back into the cavity. They are reflected multiple times between the reflector base plate 10, the secondary reflector 20 and the metal frame 40, and finally radiate outward from the gap between the secondary reflector 20 and the metal frame 40, forming high-gain directional radiation.

[0055] This application provides grounding extension structures 50 on the four sides of the secondary reflector 20 near the center, with the four grounding extension structures 50 evenly distributed around the circumference of the secondary reflector 20. This allows the four edges of the secondary reflector 20 to be electrically connected to the reflector base plate 10. The grounding extension structures on the four sides of the secondary reflector 20 form a cage structure with short circuits on all four sides. This divides the main radiation cavity into four secondary radiation cavities, achieving a uniform distribution of the electric field, reducing the cross-polarization introduced by the back cavity structure, strengthening the main polarized radiation wave, and thus improving the antenna gain.

[0056] Secondly, the edges of the four sides of the secondary reflector 20 change from open-circuit to short-circuit, altering the current distribution pattern on the secondary reflector 20. This improves the phase characteristics of the wave reflected back to the radiating element 30 from the secondary reflector 20, and reduces the reflection coefficient of the port of the radiating element 30 over a wider frequency range, thereby expanding the operating bandwidth of the antenna. At the same time, the closed cage structure formed by the secondary reflector 20 and the ground extension structure 50 can reduce the polarization leakage loss of electromagnetic waves from the edges of the secondary reflector 20, improving the utilization rate of electromagnetic energy.

[0057] Meanwhile, the secondary reflector 20, grounding extension structure 50 and reflector base plate 10 of this application can be processed by integral molding or welding, which is a mature process with low production cost and is easy to mass-produce.

[0058] Please see Figure 6 , Figure 6 and Figures 1 to 5 The structures are the same or similar, except that the radiating unit 30 may include a patch antenna 310 and a parasitic plate 320. The patch antenna 310 is attached to the reflective substrate 10, and the parasitic plate 320 is disposed between the patch antenna 310 and the secondary reflector 20.

[0059] In this embodiment, the patch antenna 310 has four feed points 310a.

[0060] Please see Figure 7 and Figure 8 This application is based on Figures 1 to 5 Taking the structure in the example as an example, the antenna structure of this embodiment was analyzed by full-wave simulation using electromagnetic simulation software. The simulation operating frequency band was 2.3GHz to 2.8GHz, and the center frequency was 2.6GHz.

[0061] Please see Figure 7 Curve S11 represents the return loss of the +45 degree polarization port, curve S22 represents the return loss of the -45 degree polarization port, and curve S21 represents the isolation between the two polarization ports.

[0062] from Figure 7 As shown by the three curves, in the frequency range of 2.5 GHz to 2.7 GHz, curves S11 and S22 are both below -10 dB, indicating that the antenna of this application has good impedance matching characteristics in this frequency band. The isolation curve S21 between the two polarization ports is better than -50 dB in the frequency range of 2.5 GHz to 2.7 GHz, indicating that the two polarization ports have excellent isolation performance, which meets the polarization isolation requirements of base station antennas. At the same time, at the center frequency of 2.6 GHz, curve S11 is about -15 dB, indicating that the antenna has good matching performance at the center frequency.

[0063] Please see Figure 8 CO is the common polarization component, and CX is the cross polarization component.

[0064] from Figure 8As shown by the two curves, the main lobe direction of the antenna is located at approximately 70 degrees and 110 degrees, and the 3dB beamwidth is approximately 33 degrees, which meets the beamwidth requirements for 33-degree split antenna scenarios and 33-degree high-speed rail coverage scenarios. Furthermore, in the main lobe direction, the common polarization component is more than 15dB higher than the cross-polarization component, indicating that the antenna of this application has good cross-polarization suppression characteristics. The peak gain of the antenna is approximately 14dBi, which is equivalent to 4 times the gain of a traditional single antenna element (approximately 8dBi) (6dB gain improvement). This means that this application achieves the high-gain design goal through the ground extension structure 50.

[0065] Please see Figures 9 to 11 , Figures 9 to 11 The structure and Figures 1 to 5 The structures are the same or similar, except that the polarization directions of the two symmetrical oscillators of the radiation unit 30 can be 0 degrees and 90 degrees respectively, so as to achieve dual polarization radiation of 0 degrees and 90 degrees; that is, one of the two symmetrical oscillators is parallel to one edge of the secondary reflector 20, and the other of the two symmetrical oscillators is parallel to the other edge of the secondary reflector 20.

[0066] For example, in Figure 10 In the middle, the secondary reflector 20 is located at the center and is square in shape. Four grounding extension structures 50 extend outward along the four corners of the secondary reflector 20 and are electrically connected to the reflective base plate 10. The radiation unit 30 is completely covered by the secondary reflector 20.

[0067] In this embodiment, the length and width of the reflective base plate 10 can range from 1.2λ to 2.0λ; for example, the length of the reflective base plate 10 is 1.6λ and the width is 1.6λ.

[0068] In this embodiment, the end of the first extension 501 away from the second extension 502 is connected to the area where the connection point of two adjacent edges of the secondary reflector 20 is located; for example, please refer to Figure 6 The regions where the first extension structure 510 and the first edge A1A2 and the second edge A2A3 are connected are connected; the regions where the second extension structure 520 and the third edge A3A4 and the second edge A2A3 are connected are connected; the regions where the third extension structure 530 and the third edge A3A4 and the fourth edge A4A1 are connected are connected; and the regions where the fourth extension structure 540 and the first edge A1A2 and the fourth edge A4A1 are connected are connected.

[0069] exist Figure 10In the first extension structure 510 and the third extension structure 530 are arranged opposite to each other, and the connecting line between the first extension portion 501 of the first extension structure 510 and the first extension portion 501 of the third extension structure 530 is B1B3; the second extension structure 520 and the fourth extension structure 540 are arranged opposite to each other, and the connecting line between the first extension portion 501 of the second extension structure 520 and the first extension portion 501 of the fourth extension structure 540 is B2B4, that is, the lengths of the connecting lines B1B3 and B2B4 are equal.

[0070] This application provides grounding extension structures 50 in the diagonal areas of the secondary reflector 20, with four grounding extension structures 50 evenly distributed along the four corners of the secondary reflector 20. This allows the four sides of the secondary reflector 20 to be electrically connected to the reflector base plate 10, forming a cage structure with four sides short-circuited. This structure divides the main radiation cavity into four secondary radiation cavities, achieving a uniform distribution of the electric field, reducing the cross-polarization introduced by the back cavity structure, strengthening the main polarized radiation wave, thereby improving the antenna gain, reducing the polarization leakage loss of electromagnetic waves from the edge of the secondary reflector 20, and improving the utilization rate of electromagnetic wave energy. It also changes the current distribution pattern on the secondary reflector 20, improving the phase characteristics of the wave reflected back from the secondary reflector 20 to the radiation element 30, and reducing the reflection coefficient of the radiation element 30 port over a wider frequency range, thereby expanding the antenna's operating bandwidth.

[0071] and Figures 9 to 10 The structure is similar; please refer to [link / reference]. Figure 11 The radiating unit 30 may include a patch antenna 310 and a parasitic plate 320. The patch antenna 310 is attached to the reflective substrate 10, and the parasitic plate 320 is disposed between the patch antenna 310 and the secondary reflector 20.

[0072] In this embodiment, the patch antenna 310 has four feed points 310a.

[0073] Please see Figure 12 , Figure 12 The grounded sub-reflector cavity antenna 100 and Figures 1 to 5 The structures are the same or similar, except that the secondary reflector 20 can be circular.

[0074] exist Figure 12 In the structure, the grounded secondary reflector cavity antenna 100 has four grounded extension structures 50, and the connecting lines of two oppositely arranged grounded extension structures 50 coincide with the center of the circle; at the same time, the included angle of the extension lines of two adjacent grounded extension structures 50 on the secondary reflector 20 is 90 degrees.

[0075] Please see Figure 13 , Figure 13 The grounded sub-reflector cavity antenna 100 and Figures 1 to 5 The structures are the same or similar, except that the secondary reflector 20 can be a regular octagon.

[0076] for Figure 13 The structure is equivalent to the structure of . Figure 1 Based on this, a chamfer is provided at each of the four apex corners of the secondary reflector 20.

[0077] Please see Figure 14 and Figure 15 , Figure 14 and Figure 15 The grounded sub-reflector cavity antenna 100 and Figures 1 to 5 The structures are the same or similar, except that the four grounding extension structures 50 are respectively connected to the four edges of the secondary reflector 20, and the connection points of the four grounding extension structures 50 are offset clockwise or counterclockwise relative to the center of the corresponding edge.

[0078] For example, in Figure 15 In the first extension structure 510, the first extension structure 510 is connected to the first edge A1A2, and the first extension structure 510 is offset counterclockwise towards the region where point A1 is located; the second extension structure 520 is connected to the region where the center of the second edge A2A3 is located, and the second extension structure 520 is offset counterclockwise towards the region where point A2 is located; the third extension structure 530 is connected to the region where the center of the third edge A3A4 is located, and the third extension structure 530 is offset counterclockwise towards the region where point A3 is located; the fourth extension structure 540 is connected to the region where the center of the fourth edge A4A1 is located, and the fourth extension structure 540 is offset counterclockwise towards the region where point A4 is located.

[0079] In this embodiment, the offsets of the centers of the corresponding edges of the first extension structure 510, the second extension structure 520, the third extension structure 530, and the fourth extension structure 540 can be the same.

[0080] In this embodiment, the four ground extension structures 50 are arranged asymmetrically around the secondary reflector 20. However, since the offset of the four ground extension structures 50 is the same, it can be equivalent to dividing the main radiation cavity into four secondary radiation cavities. Each secondary radiation cavity is asymmetrical, but the radiation pattern performance of the electromagnetic waves radiated by the four secondary radiation cavities is still symmetrical. This achieves a uniform distribution of the electric field, changes the cross current distribution introduced by the metal back cavity, improves the matching characteristics and cross polarization characteristics of the radiation element, and enhances the antenna gain and bandwidth.

[0081] This application proposes an antenna array that may include... Figures 1 to 15 Any grounded sub-reflector cavity antenna 100; for example, please refer to Figure 16The antenna array may include five grounded secondary reflector back cavity antennas 100 arranged at equal intervals along a straight line, and the spacing between two adjacent grounded secondary reflector back cavity antennas 100 may be 1.4 to 1.5λ corresponding to the center frequency point.

[0082] This application achieves a narrower beamwidth and higher gain by assembling five high-gain grounded sub-reflector cavity antennas 100 into a linear array; and since a single cavity antenna already has high gain, the antenna array of this application can significantly reduce the number of antenna elements required and simplify the design of the feed network.

[0083] It should be noted that the antenna array of this application can be applied to base station antenna systems, and is especially suitable for 33-degree split antenna scenarios and 33-degree high-speed rail coverage scenarios.

[0084] It should be noted that the arrangement and spacing of the antenna array can be adjusted according to the usage scenario and requirements.

[0085] This application proposes a grounded secondary reflector cavity antenna, comprising a reflector base plate, a secondary reflector plate, a radiating element, a metal frame, and four grounded extension structures. The secondary reflector plate is arranged opposite to and parallel to the reflector base plate. The radiating element is disposed between the reflector base plate and the secondary reflector plate. The metal frame surrounds and connects to the edge of the reflector base plate, forming a radiating cavity with the reflector base plate. The four grounded extension structures are arranged at intervals along the periphery of the secondary reflector plate. One end of each of the four grounded extension structures is connected to a different position on the edge of the secondary reflector plate, and the other end of each grounded extension structure is connected to the surface of the reflector base plate facing the secondary reflector plate. By setting grounded extension structures around the periphery of the secondary reflector plate, this application divides the main radiating cavity into four secondary radiating cavities, achieving a uniform electric field distribution, changing the cross current distribution introduced by the metal cavity, improving the matching characteristics and cross polarization characteristics of the radiating element, and enhancing the antenna gain and bandwidth.

[0086] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0087] The technical solutions provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions in the embodiments of this application.

Claims

1. A grounded sub-reflector cavity antenna, characterized in that, include: Reflective base plate; The secondary reflector is arranged opposite to and parallel to the reflector base plate; A radiating element is disposed between the reflective base plate and the secondary reflective plate; A metal frame surrounds and is connected to the edge of the reflective base plate, and together with the reflective base plate, forms a radiation cavity; as well as The four grounding extension structures are arranged at intervals along the periphery of the secondary reflector; One end of each of the four grounding extension structures is connected to a different position on the edge of the secondary reflector, and the other end of each of the four grounding extension structures is connected to the surface of the reflector base plate facing the secondary reflector.

2. The grounded secondary reflector cavity antenna according to claim 1, characterized in that, The grounding extension structure includes a first extension and a second extension connected to each other. The end of the first extension away from the second extension is connected to an edge of the secondary reflector, and the end of the second extension away from the first extension is electrically connected to the reflector base plate. The first extension is arranged parallel to the reflective base plate.

3. The grounded secondary reflector cavity antenna according to claim 2, characterized in that, The first extension and the second extension are arranged perpendicularly.

4. The grounded secondary reflector cavity antenna according to claim 2, characterized in that, The end of the first extension away from the second extension is connected to the region where the center of a side of the secondary reflector is located; Alternatively, the end of the first extension away from the second extension is connected to the region where the connection point of two adjacent edges of the secondary reflector is located. Alternatively, the four grounding extension structures are respectively connected to the four edges of the secondary reflector, and the connection points of the four grounding extension structures are offset clockwise or counterclockwise relative to the center of the corresponding edge. The length of the connecting line between the two oppositely arranged first extensions is equal to the length of the connecting line between the two oppositely arranged first extensions.

5. The grounded secondary reflector cavity antenna according to any one of claims 1 to 4, characterized in that, The line connecting the center of the secondary reflector and the center of the reflective base plate is perpendicular to the reflective base plate.

6. The grounded secondary reflector cavity antenna according to any one of claims 1 to 4, characterized in that, The outer contour of the secondary reflector is a centrally symmetrical pattern.

7. The grounded secondary reflector cavity antenna according to any one of claims 1 to 4, characterized in that, The width of the grounding extension structure ranges from 0.01λ to 0.2λ; or / and The length of the secondary reflector ranges from 0.3λ to 0.6λ, and the width of the secondary reflector ranges from 0.3λ to 0.6λ; or / and The length of the reflective base plate ranges from 1λ to 1.8λ, and the width of the reflective base plate ranges from 1λ to 1.8λ; or / and The height of the metal frame ranges from 0.3λ to 0.6λ; or / and The distance between the secondary reflector and the metal frame ranges from 0.3λ to 0.6λ. Where λ is the free space wavelength corresponding to the center frequency of the operating frequency band.

8. The grounded secondary reflector cavity antenna according to any one of claims 1 to 4, characterized in that, In the direction from the reflective base plate to the secondary reflective plate, the distance between the secondary reflective plate and the reflective base plate is less than or equal to the height of the metal frame.

9. The grounded secondary reflector cavity antenna according to any one of claims 1 to 4, characterized in that, The radiating unit includes two orthogonally arranged symmetrical oscillators, the polarization directions of the two symmetrical oscillators being positive 45 degrees and negative 45 degrees, respectively, or the polarization directions of the two symmetrical oscillators being 0 degrees and 90 degrees, respectively; Alternatively, the radiating element may include a patch antenna and a parasitic patch, wherein the patch antenna is attached to the reflective substrate and the parasitic patch is disposed between the patch antenna and the secondary reflector.

10. The grounded sub-reflector cavity antenna according to any one of claims 1 to 4, characterized in that, The distance between the center of the radiating element and the center of the reflective substrate is in the range of 0 to 0.1λ.

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