C-band small-aperture directional radiation surface wave antenna unit, array antenna and phased array optimization method

Abstract

The invention discloses a C-band small-aperture directional radiation surface wave antenna unit, an array antenna and a phased array optimization method. Due to double limitation of the size of a radiation opening surface and the material of a substrate, the number of integrated array elements and conformal installation limitation are difficult to solve at the same time; a balance micro-strip plate, a conversion plate and a waveguide transmission plate are sequentially arranged on a loading floor, the thickness of the conversion plate is sequentially decreased from one end close to the waveguide transmission plate to the other end away from the waveguide transmission plate, a coaxial line feeder connector is arranged on one side of the balance micro-strip plate, and the other side of the balance micro-strip plate is connected with one end of the conversion plate. The other end of the conversion plate is connected with one end of the waveguide transmission plate, the other end of the waveguide transmission plate is provided with a medium rod, one end of the medium rod is a connecting end, the connecting end of the medium rod is connected with the waveguide transmission plate, the other end of the medium rod is a suspended end, and the width of the medium rod is gradually reduced from the connecting end to the suspended end; and the longitudinal section of the medium rod along the central axis in the thickness direction is wedge-shaped.

Description

Technical Field

[0001] The present invention specifically relates to a C-band small-aperture directional radiation surface wave antenna unit, an array antenna and a phased array optimization method. Background Art

[0002] Directional radiation antenna, that is, directional antenna is an antenna that has a particularly strong ability to transmit and receive electromagnetic waves in one or several specific directions, and has zero or extremely small ability to transmit and receive electromagnetic waves in other directions. The working principle of directional antenna is mainly based on its radiation pattern and polarization mode. By changing the shape, size, and configuration of the radiating element and the reflecting element of the antenna, the radiation characteristics of the electromagnetic wave can be controlled. Directional antennas usually have a main beam, the direction and width of which are determined by the design and construction of the antenna. Mobile platforms such as drones require antennas to realize beam scanning functions, thereby realizing functions such as communication and detection. Due to the size limitation of the platform, the antenna must be installed in the nose and other parts to achieve forward and backward beam pointing. The existing phased array antenna array units often use microstrip form. On the one hand, this structure has a low gain. When applied to space-constrained platforms, due to the limitation of the radiation aperture size, the number of integrated array elements is limited, making the antenna array gain unable to meet the expected requirements; on the other hand, since the antenna array must be installed on the surface of the mobile platform, the antenna is required to be conformally installed to meet aerodynamic standards. Microstrip antennas are difficult to conformally install and ensure stable performance due to the limitation of the substrate material. However, the substrate material of the microstrip antenna is rigid, and it is difficult to fit tightly to the nose during processing and installation. This causes the force characteristics of the aircraft to change during flight, which in turn affects the flight speed, attitude and stability of the aircraft. Therefore, there is an urgent need to improve the common installation characteristics of the antenna and meet the original aerodynamic requirements of the aircraft. Due to the dual limitations of the radiation aperture size and the substrate material, the number of integrated array elements and conformal installation are limited and difficult to solve at the same time. At present, under the limitations of small aperture, small size and conformality, it is difficult to achieve continuous high-gain and high-performance beam scanning characteristics. The dual prominent features of small size and high gain are difficult to integrate. Summary of the invention

[0003] In order to overcome the defects of the prior art, a C-band small-aperture directional radiation surface wave antenna unit, an array antenna and a phased array optimization method are provided to solve the above problems.

[0004] A C-band small-aperture directional radiation surface wave antenna unit comprises a coaxial line feeder connector, a balanced microstrip plate, a conversion plate, a waveguide transmission plate, a dielectric rod and a loading floor, wherein the loading floor is a long strip plate body, the loading floor is arranged horizontally, the balanced microstrip plate, the conversion plate and the waveguide transmission plate are arranged vertically on the loading floor in sequence along the length direction of the loading floor, the balanced microstrip plate is a thin plate, the waveguide transmission plate is a thick plate, the conversion plate is a thickness gradient plate, the thickness of the conversion plate decreases in sequence from one end close to the waveguide transmission plate to the other end away from the waveguide transmission plate, a coaxial line feeder connector is arranged on one side of the balanced microstrip plate, the other side of the balanced microstrip plate is connected to one end of the conversion plate, the other end of the conversion plate is connected to one end of the waveguide transmission plate, the other end of the waveguide transmission plate is arranged with a dielectric rod, one end of the dielectric rod is a connecting end, the connecting end of the dielectric rod is connected to the waveguide transmission plate, the other end of the dielectric rod is a suspended end, the width of the dielectric rod decreases in sequence from the connecting end to the suspended end, and the longitudinal cross-section shape of the dielectric rod along the central axis of the thickness direction is wedge-shaped.

[0005] As a preferred solution: the dielectric rod is processed with multiple air holes along its thickness direction, and the multiple air holes are arranged in sequence along the length direction of the dielectric rod. The air holes are circular holes, and the aperture of the air holes is less than or equal to one fifth of the maximum width of the dielectric rod.

[0006] As a preferred solution: a gradual notch is formed between the top side of the loading floor and the bottom side of the dielectric rod, and the width of the gradual notch decreases from the suspended end to the connecting end.

[0007] As a preferred solution: one end of the loading floor is flush with one side of the balancing microstrip board, the other end of the loading floor is a convex end, and the horizontal distance between the convex end and the suspended end is less than or equal to one quarter of the length of the loading floor.

[0008] As a preferred solution: the coaxial line feeder connector is connected to the outer wall of one side of the balanced microstrip board, and the coaxial line feeder connector includes a connector body, an inner core strip and a baffle sleeve, the connector body is a cylinder, the baffle sleeve is an outer square inner circle sleeve, the baffle sleeve is sleeved on one end of the connector body close to the balanced microstrip board, the balanced microstrip board is respectively connected to the baffle sleeve and the connector body, one end of the inner core strip is inserted into the connector body, and the other end of the inner core strip is abutted against the outer wall of one side of the balanced microstrip board.

[0009] A C-band small-aperture directional radiation surface wave array antenna, which is composed of the above-mentioned C-band small-aperture directional radiation surface wave antenna units, and includes multiple rows of antenna components, which are arranged in sequence from top to bottom, each row of antenna components includes multiple C-band small-aperture directional radiation surface wave antenna units, and the multiple C-band small-aperture directional radiation surface wave antenna units are arranged in sequence at intervals, and a first gap is formed between every two adjacent C-band small-aperture directional radiation surface wave antenna units. In two adjacent rows of antenna components, multiple C-band small-aperture directional radiation surface wave antenna units in the upper row of antenna components and multiple C-band small-aperture directional radiation surface wave antenna units in the lower row of antenna components are arranged in a one-to-one correspondence, and a second gap is formed between a C-band small-aperture directional radiation surface wave antenna unit in the upper row of antenna components and a corresponding C-band small-aperture directional radiation surface wave antenna unit in the lower row of antenna components; Each C-band small-aperture directional radiation surface wave antenna unit includes a coaxial line feeder connector, a balanced microstrip plate, a conversion plate, a waveguide transmission plate, a dielectric rod and a loading floor. The loading floor is a long strip plate body, the loading floor is arranged horizontally, the balanced microstrip plate, the conversion plate and the waveguide transmission plate are arranged vertically on the loading floor in sequence along the length direction of the loading floor, the balanced microstrip plate is a thin plate, the waveguide transmission plate is a thick plate, the conversion plate is a thickness gradient plate, the thickness of the conversion plate decreases from one end close to the waveguide transmission plate to the other end away from the waveguide transmission plate, a coaxial line feeder connector is arranged on one side of the balanced microstrip plate, the other side of the balanced microstrip plate is connected to one end of the conversion plate, the other end of the conversion plate is connected to one end of the waveguide transmission plate, the other end of the waveguide transmission plate is arranged with a dielectric rod, one end of the dielectric rod is a connecting end, the connecting end of the dielectric rod is connected to the waveguide transmission plate, the other end of the dielectric rod is a suspended end, the width of the dielectric rod decreases from the connecting end to the suspended end, and the longitudinal cross-section shape of the dielectric rod along the central axis of the thickness direction is wedge-shaped.

[0010] The phased array optimization method of the C-band small aperture directional radiation surface wave array antenna is realized by using the above-mentioned C-band small aperture directional radiation surface wave array antenna. The phased array optimization method is to optimize the excitation amplitude distribution of the C-band small aperture directional radiation surface wave array antenna when the C-band small aperture directional radiation surface wave array antenna is composed of multiple C-band small aperture directional radiation surface wave antenna units, and the array element radiation pattern obtained by full-wave simulation software is exported. After the exported array element radiation pattern is multiplied by the array factor, the array radiation pattern is directly optimized in combination with artificial intelligence technology. The obtained optimization result is compared with the standard index requirements, thereby completing the optimization process of the excitation amplitude distribution of the C-band small aperture directional radiation surface wave array antenna.

[0011] The beneficial effects of the present invention are: 1. The C-band small-aperture directional radiation surface wave antenna unit in the present invention is formed by the cooperation of the coaxial line feeder connector, the balanced microstrip board, the conversion board, the waveguide transmission board, the dielectric rod and the loading floor to form an antenna unit structure that can achieve a high gain effect under small aperture conditions, so that the dual characteristics of small aperture and high gain are taken into account simultaneously, and is less affected by the surrounding environment. It is suitable for different installation conditions and installation curved surface structures, improves the emergency response capability of rapid processing, and is suitable for harsh or other rapid response use environments.

[0012] 2. The C-band small-aperture directional radiation surface wave array antenna in the present invention is an array antenna with a reasonable structural arrangement. It can control the antenna pattern electronically to achieve a beam scanning function. When in use, it is installed on a bracket structure that is conformal to the nose of the aircraft and can be attached and adapted to any curved surface. The C-band small-aperture directional radiation surface wave array antenna of the present invention has little effect on the original aerodynamic characteristics of the carrier, and is more suitable for aircraft applications, and can be adapted for use in emergency or other harsh extreme environments.

[0013] 3. The phased array optimization method of the C-band small-aperture directional radiation surface wave array antenna in the present invention can optimize the excitation amplitude distribution of the C-band small-aperture directional radiation surface wave array antenna, which is beneficial to the performance estimation of the C-band small-aperture directional radiation surface wave array antenna before use and the feedback evaluation after use, and is beneficial to improving the comprehensive data control of the C-band small-aperture directional radiation surface wave array antenna and the quality of subsequent improvement and optimization processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of a first three-dimensional structure of a C-band small-aperture directional radiation surface wave antenna unit; Figure 2 It is a schematic diagram of the second three-dimensional structure of the C-band small-aperture directional radiation surface wave antenna unit.

[0015] Figure 3 It is a three-dimensional structural schematic diagram of a coaxial line feeder connector; Figure 4 This is a schematic diagram of the main structure of a C-band small-aperture directional radiation surface wave array antenna, which shows a 5×5 C-band small-aperture directional radiation surface wave array antenna; Figure 5 The top view of the structure of a C-band small aperture directional radiation surface wave array antenna is shown in the figure, which shows a 5×5 C-band small aperture directional radiation surface wave array antenna; Figure 6 The figure is a schematic diagram of the three-dimensional structure of a C-band small-aperture directional radiation surface wave array antenna, which shows a 5×5 C-band small-aperture directional radiation surface wave array antenna; Figure 7It is a schematic diagram of the reflection coefficient and center operating frequency gain of the C-band small aperture directional radiation surface wave antenna unit; Figure 8 Schematic diagram of scanning gain direction of 1×5 antenna array; Fig. 9 Schematic diagram of scanning gain direction of 5×5 antenna array, showing the xoz plane; Fig.10 The schematic diagram of the scanning gain direction of the 5×5 antenna array shows the yoz plane; Fig.11 This is a schematic diagram of the direction of the uniformly distributed phased array antenna when N=12; Fig.12 It is a rectangular coordinate diagram of the amplitude-weighted low sidelobe array when N=12; Fig.13 It is a logical diagram of the traditional optimization method; Fig.14 It is a schematic diagram of the process of the phased array optimization method in the present invention.

[0016] In the figure: 1-coaxial feeder connector; 1-1-connector body; 1-2-inner core strip; 1-3-blocking sleeve; 2-balanced microstrip board; 3-conversion board; 4-waveguide transmission board; 5-dielectric rod; 5-1-suspended end; 5-2-air hole; 6-loading floor; 6-1-outer convex end; 7-gradient notch; 10-C-band small aperture directional radiation surface wave antenna unit; 11-first gap; 12-second gap. DETAILED DESCRIPTION

[0017] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0018] Specific implementation method 1: Combination Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Fig. 9 , Fig.10 , Fig.11 , Fig.12 , Fig.13 and Fig.14The present embodiment is described. The present embodiment comprises a coaxial line feeder connector 1, a balanced microstrip plate 2, a conversion plate 3, a waveguide transmission plate 4, a dielectric rod 5 and a loading floor 6. The loading floor 6 is a long strip plate. The loading floor 6 is arranged horizontally. The balanced microstrip plate 2, the conversion plate 3 and the waveguide transmission plate 4 are arranged vertically on the loading floor 6 in sequence along the length direction of the loading floor 6. The balanced microstrip plate 2 is a thin plate, the waveguide transmission plate 4 is a thick plate, the conversion plate 3 is a thickness gradient plate, and the thickness of the conversion plate 3 increases from one end close to the waveguide transmission plate 4 to the other end away from the waveguide transmission plate 4. The ends decrease in sequence, a coaxial feeder connector 1 is provided on one side of the balanced microstrip board 2, the other side of the balanced microstrip board 2 is connected to one end of the conversion board 3, the other end of the conversion board 3 is connected to one end of the waveguide transmission board 4, the other end of the waveguide transmission board 4 is provided with a dielectric rod 5, one end of the dielectric rod 5 is a connecting end, the connecting end of the dielectric rod 5 is connected to the waveguide transmission board 4, the other end of the dielectric rod 5 is a suspended end 5-1, the width of the dielectric rod 5 decreases from the connecting end to the suspended end 5-1, and the longitudinal cross-section shape of the dielectric rod 5 along the central axis of the thickness direction is a wedge shape. The dielectric rod 5 is a radiation structure, and the optimal shape of the longitudinal cross-section of the dielectric rod 5 along the central axis of the thickness direction is an isosceles triangle.

[0019] In this embodiment, the balanced microstrip board 2 is a board with a balanced microstrip line structure, which is specifically a microstrip line structure with equal width at the upper and lower ends, and plays a role of balanced feeding. The lower end of the balanced microstrip board 2 is fixedly connected to the loading floor 6, and the loading floor 6 is a dielectric substrate with a thickness of 1.6 mm. The dielectric constant of the dielectric substrate is 2.2, and it is connected to a 50Ω coaxial connector.

[0020] In this embodiment, the optimal length of the waveguide transmission plate 4 is 20 mm, the optimal height of the waveguide transmission plate 4 is 15 mm, and the optimal thickness of the waveguide transmission plate 4 is 6 mm. The side wall of the waveguide transmission plate 4 is wrapped with metal or uses a metallized via array, which is conducive to the formation of the boundary conditions of the waveguide.

[0021] In this embodiment, the balanced microstrip plate 2, the conversion plate 3, and the waveguide transmission plate 4 are all hollow plates filled with the same medium for easy integrated processing. The filling principle and the filling medium are both existing technologies, and are the same as the relevant filling principles and media of the existing antenna unit.

[0022] The conversion plate 3 in this embodiment is a conversion structure, which has a linear gradient from the width of the balanced microstrip plate 2 to the width of the waveguide transmission plate 4 in width, and a linear or stacked gradient from the thickness of the balanced microstrip plate 2 to the height of the waveguide transmission plate 4 in thickness, and a length of 30 mm, so as to realize impedance matching and mode conversion from the balanced microstrip plate 2 to the waveguide transmission plate 4.

[0023] In this embodiment, the dielectric rod 5 is essentially a radiation structure, which is composed of a linear gradient metal extending from the waveguide aperture, and realizes a gradient structure from the waveguide aperture to the free space. As a waveguide-free space impedance matching structure, it improves the radiation efficiency and reduces the standing wave ratio.

[0024] In this embodiment, the loading floor 6 serves as a bottom support and provides a location for arranging the balanced microstrip board 2 , the conversion board 3 , the waveguide transmission board 4 and the dielectric rod 5 .

[0025] Furthermore, the balanced microstrip board 2 is a balanced feeding structure, the balanced microstrip board 2 is connected to the coaxial line feeder connector 1, the size of the waveguide transmission board 4 is 15mm×6mm×20mm, which is convenient for integrated processing, wherein the side wall is wrapped with metal to achieve convenient conditions for the waveguide, wherein the conversion board 3 is a linear gradient from the width of the balanced microstrip board 2 to the width of the waveguide transmission board 4, thereby achieving impedance matching and mode conversion from the balanced microstrip board 2 to the waveguide transmission board 4.

[0026] Specific embodiment 2: This embodiment is a further limitation of specific embodiment 1. The dielectric rod 5 is processed with multiple air holes 5-2 along its thickness direction. The multiple air holes 5-2 are arranged in sequence along the length direction of the dielectric rod 5. The air holes 5-2 are circular holes, and the aperture of the air holes 5-2 is less than or equal to one fifth of the maximum width of the dielectric rod 5. The above-mentioned dimensional relationship is the optimal dimensional processing relationship formed during the processing, which is conducive to improving the gain of the antenna unit.

[0027] Furthermore, the dielectric rod 5 is processed with a plurality of air holes 5-2 along its thickness direction. The arrangement positions and connectivity of the plurality of air holes 5-2 can realize the structural form of a small-caliber traveling wave array. The processing of the air holes 5-2 can better realize the antenna characteristics, which is conducive to improving the gain of the antenna unit. The necessary structural features of the antenna unit not mentioned in this embodiment are the same as the necessary structural features of the existing antenna unit.

[0028] Specific implementation method three: This implementation method is a further limitation of specific implementation method one or two. A gradient notch 7 is formed between the top side of the loading floor 6 and the bottom side of the dielectric rod 5. The width of the gradient notch 7 decreases from the suspended end 5-1 to the connection end. The opening direction and form of the gradient notch 7 are conducive to coordinating the structural forms of the coaxial line feeder connector 1, the balanced microstrip board 2, the conversion board 3, the waveguide transmission board 4, the dielectric rod 5 and the loading floor 6.

[0029] Specific embodiment 4: This embodiment is a further limitation of specific embodiments 1, 2 or 3. One end of the loading floor 6 is flush with one side of the balanced microstrip board 2, and the other end of the loading floor 6 is a convex end 6-1. The horizontal distance between the convex end 6-1 and the suspended end 5-1 is less than or equal to one quarter of the length of the loading floor 6. The above-mentioned dimensional relationship is the optimal dimensional relationship summarized in the modeling and processing process, which is conducive to improving the gain of the antenna unit. In this embodiment, the setting position of the loading floor 6 below the balanced microstrip board 2, the conversion board 3, the waveguide transmission board 4 and the dielectric rod 5 can achieve better impedance and radiation characteristics.

[0030] Specific implementation mode five: This implementation mode is a further limitation of specific implementation modes one, two, three or four. The coaxial line feeder connector 1 is connected to an outer wall of one side of the balanced microstrip board 2. The coaxial line feeder connector 1 includes a connector body 1-1, an inner core strip 1-2 and a baffle 1-3. The connector body 1-1 is a cylinder, and the baffle 1-3 is an outer square inner circle sleeve. The baffle 1-3 is mounted on one end of the connector body 1-1 close to the balanced microstrip board 2. The balanced microstrip board 2 is respectively connected to the baffle 1-3 and the connector body 1-1. One end of the inner core strip 1-2 is inserted into the connector body 1-1, and the other end of the inner core strip 1-2 is abutted against an outer wall of one side of the balanced microstrip board 2.

[0031] Furthermore, the coaxial feeder connector 1 can quickly receive signals and reduce signal interference. It is also suitable for use in harsh or other rapid response environments and can effectively improve the performance of rapid emergency signal reception.

[0032] Specific implementation method six: Combining 1 to Fig.14 The present embodiment is described. The C-band small-aperture directional radiation surface wave array antenna in the present embodiment includes multiple rows of antenna components. The multiple rows of antenna components are arranged sequentially from top to bottom. Each row of antenna components includes multiple C-band small-aperture directional radiation surface wave antenna units 10. The multiple C-band small-aperture directional radiation surface wave antenna units 10 are arranged in sequence at intervals. A first gap 11 is formed between every two adjacent C-band small-aperture directional radiation surface wave antenna units 10. In two adjacent rows of antenna components, the multiple C-band small-aperture directional radiation surface wave antenna units 10 in the upper row of antenna components and the multiple C-band small-aperture directional radiation surface wave antenna units 10 in the lower row of antenna components are arranged one-to-one. A second gap 12 is formed between a C-band small-aperture directional radiation surface wave antenna unit 10 in the upper row of antenna components and its corresponding C-band small-aperture directional radiation surface wave antenna unit 10 in the lower row of antenna components. Each C-band small-aperture directional radiation surface wave antenna unit 10 comprises a coaxial line feeder connector 1, a balanced microstrip plate 2, a conversion plate 3, a waveguide transmission plate 4, a dielectric rod 5 and a loading floor 6, wherein the loading floor 6 is a long strip plate, the loading floor 6 is arranged horizontally, the balanced microstrip plate 2, the conversion plate 3 and the waveguide transmission plate 4 are arranged vertically on the loading floor 6 in sequence along the length direction of the loading floor 6, the balanced microstrip plate 2 is a thin plate, the waveguide transmission plate 4 is a thick plate, the conversion plate 3 is a thickness gradient plate, and the thickness of the conversion plate 3 increases from one end close to the waveguide transmission plate 4 to the other end away from the waveguide transmission plate 4. One end of the balanced microstrip board 2 decreases in sequence, a coaxial line feeder connector 1 is provided on one side of the balanced microstrip board 2, the other side of the balanced microstrip board 2 is connected to one end of the conversion board 3, the other end of the conversion board 3 is connected to one end of the waveguide transmission board 4, and the other end of the waveguide transmission board 4 is provided with a dielectric rod 5, one end of the dielectric rod 5 is a connecting end, the connecting end of the dielectric rod 5 is connected to the waveguide transmission board 4, and the other end of the dielectric rod 5 is a suspended end 5-1, the width of the dielectric rod 5 decreases in sequence from the connecting end to the suspended end 5-1, and the optimal shape of the longitudinal cross-section of the dielectric rod 5 along the central axis of the thickness direction is an isosceles triangle.

[0033] In this embodiment, the coaxial feeder connector 1 includes a connector body 1-1, an inner core strip 1-2 and a baffle 1-3, wherein the connector body 1-1 is a cylindrical body, and the baffle 1-3 is an outer square inner circle sleeve body, and the baffle 1-3 is sleeved at one end of the connector body 1-1 close to the balanced microstrip board 2, and the balanced microstrip board 2 is respectively connected to the baffle 1-3 and the connector body 1-1, and one end of the inner core strip 1-2 is inserted into the connector body 1-1, and the other end of the inner core strip 1-2 is attached to the outer wall of one side of the balanced microstrip board 2. The coaxial feeder connector 1 can quickly receive signals and reduce signal interference, and is suitable for harsh or other rapid response use environments, and can effectively improve the performance of rapid emergency signal reception.

[0034] In this embodiment, the balanced microstrip board 2 is a balanced feeding structure, the balanced microstrip board 2 is connected to the coaxial line feeder connector 1, the size of the waveguide transmission board 4 is 15mm×6mm×20mm, which is convenient for integrated processing, wherein the side wall is wrapped with metal, which can realize the convenient conditions of the waveguide, wherein the conversion board 3 is a linear gradient from the width of the balanced microstrip board 2 to the width of the waveguide transmission board 4, thereby realizing impedance matching and mode conversion from the balanced microstrip board 2 to the waveguide transmission board 4.

[0035] The conversion plate 3 in this embodiment is a conversion structure, which has a linear gradient from the width of the balanced microstrip plate 2 to the width of the waveguide transmission plate 4 in width, and a linear or stacked gradient from the thickness of the balanced microstrip plate 2 to the height of the waveguide transmission plate 4 in thickness, and a length of 30 mm, so as to realize impedance matching and mode conversion from the balanced microstrip plate 2 to the waveguide transmission plate 4.

[0036] In this embodiment, the optimal length of the waveguide transmission plate 4 is 20 mm, the optimal height of the waveguide transmission plate 4 is 15 mm, and the optimal thickness of the waveguide transmission plate 4 is 6 mm. The side wall of the waveguide transmission plate 4 is wrapped with metal or uses a metallized via array, which is conducive to the formation of the boundary conditions of the waveguide.

[0037] In this embodiment, the dielectric rod 5 is essentially a radiation structure, which is composed of a linear gradient metal extending from the waveguide aperture, and realizes a gradient structure from the waveguide aperture to the free space. As a waveguide-free space impedance matching structure, the radiation efficiency is improved and the standing wave ratio is reduced. The dielectric rod 5 is processed with a plurality of air holes 5-2 along its thickness direction, and the plurality of air holes 5-2 are arranged in sequence along the length direction of the dielectric rod 5. The air holes 5-2 are circular holes, and the aperture of the air holes 5-2 is less than or equal to one fifth of the maximum width of the dielectric rod 5. The above-mentioned dimensional relationship is the optimal dimensional processing relationship formed during the processing, which is conducive to improving the gain of the antenna unit.

[0038] In this embodiment, the balanced microstrip plate 2, the conversion plate 3, and the waveguide transmission plate 4 are all hollow plates filled with the same medium for easy integrated processing. The filling principle and the filling medium are both existing technologies, and are the same as the relevant filling principles and media of the existing antenna unit.

[0039] In this embodiment, the loading floor 6 serves as a bottom support and provides a location for arranging the balanced microstrip board 2 , the conversion board 3 , the waveguide transmission board 4 and the dielectric rod 5 .

[0040] In this embodiment, a gradient notch 7 is formed between the top side of the loading floor 6 and the bottom side of the dielectric rod 5. The width of the gradient notch 7 decreases from the suspended end 5-1 to the connection end. The opening direction and form of the gradient notch 7 are conducive to matching the structural form of the coaxial line feeder connector 1, the balanced microstrip board 2, the conversion board 3, the waveguide transmission board 4, the dielectric rod 5 and the loading floor 6.

[0041] In this embodiment, one end of the loading floor 6 is flush with one side of the balanced microstrip board 2, and the other end of the loading floor 6 is a convex end 6-1, and the horizontal distance between the convex end 6-1 and the suspended end 5-1 is less than or equal to one quarter of the length of the loading floor 6. The above-mentioned dimensional relationship is the optimal dimensional relationship summarized in the modeling and processing process, which is conducive to improving the gain of the antenna unit. In this embodiment, the setting position of the loading floor 6 below the balanced microstrip board 2, the conversion board 3, the waveguide transmission board 4 and the dielectric rod 5 can achieve better impedance and radiation characteristics.

[0042] Specific implementation method seven: Combination Figures 1 to 14To explain this embodiment, the phased array optimization method in this embodiment is to optimize the excitation amplitude distribution of the C-band small aperture directional radiation surface wave array antenna when a C-band small aperture directional radiation surface wave array antenna is composed of multiple C-band small aperture directional radiation surface wave antenna units 10, and the array element radiation pattern obtained by full-wave simulation software is exported. After the exported array element radiation pattern is multiplied by the array factor, the array radiation pattern is directly optimized in combination with artificial intelligence technology, and the obtained optimization result is compared with the standard index requirements, thereby completing the optimization process of the excitation amplitude distribution of the C-band small aperture directional radiation surface wave array antenna.

[0043] In this embodiment, the width of the dielectric rod 5 decreases gradually from one end close to the waveguide transmission plate 4 to the other end far from the waveguide transmission plate 4, wherein the dielectric rod 5 is a directional radiation antenna composed of a slender dielectric rod, and its gain is positively correlated with the longitudinal length of the dielectric rod, and a high gain characteristic can be achieved under a small aperture limit. In addition, due to its flexible processing method, mechanical, electronic, and 3D printing processing technologies can be used in combination, and conformal installation can be achieved under the condition of ensuring stable performance.

[0044] The present invention uses a dielectric rod antenna as a phased array unit for the first time. Under small aperture limitations, multiple matching structures are used to achieve high-gain directional radiation characteristics, significantly improving the antenna unit gain. In addition, a loading floor 6, specifically a metal floor, is loaded on one side of the wide side of the antenna, which can better achieve impedance and radiation characteristics.

[0045] The structural dimensions of the C-band small-aperture directional radiation surface wave antenna unit in the present invention can be manufactured into different specifications according to specific requirements, which are 15 mm, 6 mm and 160 mm respectively. The operating frequency band is 5.8-7.0 GHz, the typical standing wave ratio in the band is less than 2, and the minimum value is 1.0. The directional radiation gain at the typical operating frequency point of 6.4 GHz in the band is 9.35 dBi.

[0046] The optimal dimensions of the balanced microstrip plate 2, the conversion plate 3, the waveguide transmission plate 4, the dielectric rod 5 and the loading floor 6 in the process of mutual cooperation in the present invention are: The size of the balanced microstrip plate 2 is 10 mm, the length of the conversion plate 3 is 30 mm, the length of the waveguide transmission plate 4 is 20 mm, the length of the dielectric rod 5 is 80 mm, and the length of the loading floor 6 is 160 mm; the maximum thickness of the conversion plate 3, the thickness of the waveguide transmission plate 4 and the dielectric rod 5 are all 6 mm; the maximum width of the balanced microstrip plate 2, the conversion plate 3, the waveguide transmission plate 4 and the dielectric rod 5 are all 15 mm.

[0047] Specific implementation method seven: This implementation method is a further limitation of specific implementation methods one, two, three, four, five or six. After the C-band small-aperture directional radiation surface wave antenna units in the present invention form an array antenna, the excitation amplitude distribution needs to be optimized to improve the electrical performance of the antenna. The present invention proposes a phased array optimization method that introduces the influence of array element radiation.

[0048] Combination Figures 1 to 14 As shown, the C-band small-aperture directional radiation surface wave antenna unit in the present invention forms a one-dimensional antenna array, which can realize the one-dimensional beam scanning function under space-constrained conditions. Here, a 1×5 array is taken as an example, the antenna unit spacing is selected to be 18 mm, and the dielectric rod antenna units are formed into a 1×5 array. By controlling the feed phase to change from -60° to 60°, the beam scanning function within the range of ±20° in a one-dimensional plane can be realized, and the gain is greater than 9.5 dBi. By simulating the gain change curve of the antenna with frequency, the overall gain of the antenna is greater than 13.5 dBi.

[0049] Combination Figure 8 , Fig. 9 and Fig.10 As shown, the C-band small-aperture directional radiation surface wave array antenna in the present invention can realize the two-dimensional beam scanning function under space-constrained conditions. Here, taking a 5×5 array as an example, the array spacing in the x direction is selected as 22.5 mm, and the spacing in the y direction is selected as 18 mm. Combined with the structural dimensions of the antenna unit, the aperture dimensions of the antenna array are: 105 mm in the x direction and 78 mm in the y direction. When the phase variation is -60 to 60°, the phased array antenna can achieve a scanning range of ±20° in the xoz plane and yoz plane, and the overall gain is higher than 16 dBi.

[0050] In the present invention, for the radiation field of the phased array antenna, in order to obtain low side lobes of the radiation pattern, commonly used methods include amplitude weighting, phase weighting, density weighting and other array weighting.

[0051] Amplitude weighting is to achieve low side lobes in the radiation field of phased array antennas by controlling the feeding amplitude of each unit. A large number of analytical methods and engineering optimization algorithms have emerged in the research of amplitude weighting to control side lobes, such as Taylor synthesis and Chebyshev synthesis. However, amplitude weighting requires each unit of the phased array antenna to be connected to an attenuator with different weights, which greatly increases the cost of the system and the complexity of feeding.

[0052] In addition, phase weighting is to achieve low side lobes in the radiation field of the phased array antenna by controlling the feeding phase of each unit. However, the effect of phase weighting in achieving low side lobes is limited, and it is difficult to obtain better low side lobe performance indicators by phase weighting alone. Moreover, phase weighting cannot be used to achieve low side lobes in the radiation field.

[0053] In addition, there are two types of density weighting, specifically: 1) One is an array of equal amplitude and unequal spacing, that is, the units in the array are symmetrical with the middle unit, and the unit spacing increases from the center of the array to the edge of the array. However, the resulting irregular radiation unit spacing brings great difficulties to the array surface structure design, heat dissipation design, and process processing.

[0054] 2) The other is a sparse array with equal amplitude and spacing, that is, the existence of antenna units in the array grid is determined according to a certain rule, so as to form a sparse arrangement of phased array antennas to achieve the purpose of low side lobes. Compared with a full array with the same aperture, this sparse array has almost the same main lobe width, but has a narrower main lobe and higher resolution relative to the number of units. At the same time, the sparse array is cheaper than the full array, so it is well used in large phased array antennas.

[0055] The present invention takes a one-dimensional linear array with 12 array elements as an example, and compares the radiation patterns after equal amplitude excitation and Chebyshev weighting. It can be seen that after amplitude weighting, the sidelobe level is reduced, and the radiation energy is concentrated in the main lobe range. The pattern multiplication principle, that is, the overall array pattern is equal to the product of the array element pattern and the array factor. The current phased array antenna optimization process focuses on the comprehensive angle of the array factor. This optimization process regards the array element pattern as the omnidirectional radiation of an ideal point source, so that the actual array pattern obtained by this method deviates from the optimization result, especially when there is an offset in the maximum radiation direction of the array element pattern. This phenomenon is more obvious. This makes it difficult for the optimization results obtained when applying phased array antenna optimization design methods such as neural networks to meet the index requirements.

[0056] This invention introduces the influence of array element pattern into the phased array optimization process for the first time, derives the array element pattern obtained by full-wave simulation software, multiplies it by the array factor, and directly optimizes the array pattern in combination with artificial intelligence technology. The obtained optimization result meets the index requirements. Compared with the existing optimization scheme, this method has a simpler optimization process, can perform targeted optimization according to the radiation characteristics of the array element antenna, and can further improve the antenna performance.

[0057] Combination Fig.13 and Fig.14 As shown in the figure, through the optimization comparison results of the optimization method of the present invention and the traditional method, it can be seen that the radiation field of the antenna is greatly different before and after the influence of the array element pattern is introduced. The array factor is optimized by the traditional existing optimization method to meet the index requirements. After the actual array element is introduced, there is a great deviation between the result and the index. The optimization method proposed by the present invention directly optimizes the array pattern. The results show that the optimization method of the present invention fully meets the index requirements and reduces the relevant difficulty in the optimization process.

Claims

1. A C-band small aperture directional radiation surface wave antenna unit, characterized in that: The invention comprises a coaxial line feeder connector (1), a balanced microstrip plate (2), a conversion plate (3), a waveguide transmission plate (4), a dielectric rod (5) and a loading floor (6), wherein the loading floor (6) is a long strip plate body, the loading floor (6) is arranged horizontally, the balanced microstrip plate (2), the conversion plate (3) and the waveguide transmission plate (4) are arranged vertically on the loading floor (6) in sequence along the length direction of the loading floor (6), the balanced microstrip plate (2) is a thin plate, the waveguide transmission plate (4) is a thick plate, the conversion plate (3) is a thickness gradient plate, and the thickness of the conversion plate (3) increases from one end close to the waveguide transmission plate (4) to the other end far from the waveguide transmission plate (4). The balanced microstrip plate (2) is provided with a coaxial feeder connector (1) on one side, the other side of the balanced microstrip plate (2) is connected to one end of a conversion plate (3), the other end of the conversion plate (3) is connected to one end of a waveguide transmission plate (4), the other end of the waveguide transmission plate (4) is provided with a dielectric rod (5), one end of the dielectric rod (5) is a connection end, the connection end of the dielectric rod (5) is connected to the waveguide transmission plate (4), the other end of the dielectric rod (5) is a suspended end (5-1), the width of the dielectric rod (5) decreases from the connection end to the suspended end (5-1), and the longitudinal cross-section shape of the dielectric rod (5) along the central axis in the thickness direction is a wedge shape.

2. The C-band small aperture directional radiation surface wave antenna unit according to claim 1, characterized in that: The dielectric rod (5) is processed with a plurality of air holes (5-2) along its thickness direction. The plurality of air holes (5-2) are arranged in sequence along the length direction of the dielectric rod (5). The air holes (5-2) are circular holes. The diameter of the air holes (5-2) is less than or equal to one fifth of the maximum width of the dielectric rod (5).

3. The C-band small aperture directional radiation surface wave antenna unit according to claim 1, characterized in that: A gradient notch (7) is formed between the top side of the loading floor (6) and the bottom side of the dielectric rod (5), and the width of the gradient notch (7) decreases from the suspended end (5-1) to the connection end.

4. The C-band small aperture directional radiation surface wave antenna unit according to claim 3, characterized in that: One end of the loading floor (6) is arranged flush with one side of the balancing microstrip plate (2), and the other end of the loading floor (6) is an outer convex end (6-1), and the horizontal distance between the outer convex end (6-1) and the suspended end (5-1) is less than or equal to one quarter of the length of the loading floor (6).

5. The C-band small aperture directional radiation surface wave antenna unit according to claim 1, characterized in that: The coaxial line feeder connector (1) is connected to an outer wall of one side of a balanced microstrip board (2). The coaxial line feeder connector (1) comprises a connector body (1-1), an inner core strip (1-2) and a baffle (1-3). The connector body (1-1) is a cylindrical body. The baffle (1-3) is a sleeve body with an outer square and an inner circle. The baffle (1-3) is sleeved on one end of the connector body (1-1) close to the balanced microstrip board (2). The balanced microstrip board (2) is respectively connected to the baffle (1-3) and the connector body (1-1). One end of the inner core strip (1-2) is inserted into the connector body (1-1), and the other end of the inner core strip (1-2) is attached to an outer wall of one side of the balanced microstrip board (2).

6. A C-band small aperture directional radiation surface wave array antenna, comprising the C-band small aperture directional radiation surface wave antenna unit according to any one of claims 1 to 5, characterized in that: The invention comprises a plurality of rows of antenna assemblies, which are arranged in sequence from top to bottom, each row of antenna assemblies comprises a plurality of C-band small-aperture directional radiation surface wave antenna units (10), the plurality of C-band small-aperture directional radiation surface wave antenna units (10) are arranged in sequence at intervals, a first gap (11) is formed between every two adjacent C-band small-aperture directional radiation surface wave antenna units (10), the plurality of C-band small-aperture directional radiation surface wave antenna units (10) in the upper row of antenna assemblies and the plurality of C-band small-aperture directional radiation surface wave antenna units (10) in the lower row of antenna assemblies in two adjacent rows of antenna assemblies are arranged in a one-to-one correspondence, and a second gap (12) is formed between a C-band small-aperture directional radiation surface wave antenna unit (10) in the upper row of antenna assemblies and a corresponding C-band small-aperture directional radiation surface wave antenna unit (10) in the lower row of antenna assemblies; Each C-band small-aperture directional radiation surface wave antenna unit (10) comprises a coaxial line feeder connector (1), a balanced microstrip plate (2), a conversion plate (3), a waveguide transmission plate (4), a dielectric rod (5) and a loading floor (6); the loading floor (6) is a long strip plate; the loading floor (6) is arranged horizontally; the balanced microstrip plate (2), the conversion plate (3) and the waveguide transmission plate (4) are arranged vertically on the loading floor (6) in sequence along the length direction of the loading floor (6); the balanced microstrip plate (2) is a thin plate; the waveguide transmission plate (4) is a thick plate; the conversion plate (3) is a thickness gradient plate; the thickness of the conversion plate (3) increases from one end close to the waveguide transmission plate (4) to the end far from the waveguide transmission plate (4). The other end of the transmission plate (4) decreases in sequence; a coaxial line feeder connector (1) is provided on one side of the balanced microstrip plate (2); the other side of the balanced microstrip plate (2) is connected to one end of the conversion plate (3); the other end of the conversion plate (3) is connected to one end of the waveguide transmission plate (4); a dielectric rod (5) is provided on the other end of the waveguide transmission plate (4); one end of the dielectric rod (5) is a connection end; the connection end of the dielectric rod (5) is connected to the waveguide transmission plate (4); the other end of the dielectric rod (5) is a suspended end (5-1); the width of the dielectric rod (5) decreases in sequence from the connection end to the suspended end (5-1); and the longitudinal cross-section shape of the dielectric rod (5) along the central axis in the thickness direction thereof is a wedge shape.

7. A phased array optimization method for a C-band small aperture directional radiation surface wave array antenna, implemented using the C-band small aperture directional radiation surface wave array antenna according to claim 6, characterized in that: The phased array optimization method is to optimize the excitation amplitude distribution of the C-band small aperture directional radiation surface wave array antenna when a C-band small aperture directional radiation surface wave array antenna is formed by multiple C-band small aperture directional radiation surface wave antenna units (10), and to export the array element radiation pattern obtained by full-wave simulation software. After the exported array element radiation pattern is multiplied by the array factor, the array radiation pattern is directly optimized in combination with artificial intelligence technology. The obtained optimization result is compared with the standard index requirement, thereby completing the optimization process of the excitation amplitude distribution of the C-band small aperture directional radiation surface wave array antenna.

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