C-band small aperture directive radiating surface wave antenna element, array antenna and phased array optimization method

Abstract

C-band small aperture directional radiation surface wave antenna unit, array antenna and phased array optimization method. Due to the dual restrictions of the radiation aperture size and the substrate material, the integrated array element number and conformal installation are limited and difficult to solve; in the present application, the balanced microstrip plate, the conversion plate and the waveguide transmission plate are sequentially arranged on the loaded floor, 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, one side of the balanced microstrip plate is provided with a coaxial line feeder joint, the other side of the balanced microstrip 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 dielectric rod, one end of the dielectric rod is a connecting end, the connecting end of the dielectric rod is connected with 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 section shape of the dielectric rod along the central axis of the thickness direction is wedge-shaped.

Description

TECHNICAL FIELD

[0001] The present application relates to a C-band small-aperture directional radiation surface wave antenna unit, array antenna and phased array optimization method. BACKGROUND

[0002] A directional antenna, also known as a directional antenna, is an antenna that has a particularly strong ability to transmit and receive electromagnetic waves in one or more specific directions, while having a zero or minimal ability to transmit and receive electromagnetic waves in other directions. The working principle of a directional antenna is mainly based on its radiation pattern and polarization mode. By changing the shape, size, and configuration of the radiating elements and reflecting elements of the antenna, the radiation characteristics of electromagnetic waves can be controlled. A directional antenna usually has a main beam, and the direction and width of the beam are determined by the design and structure of the antenna. Mobile platforms such as drones require antennas to achieve beam scanning functions, thereby achieving communication, detection and other functions. Due to size limitations, antennas must be installed on the nose or other parts of the platform to achieve forward and backward beam pointing. The existing phased array antenna array unit is often in the form of a microstrip. This structure has low gain, and in space-limited platform applications, due to the limitation of the radiation aperture size, the number of integrated array elements is limited, making it difficult to achieve the desired antenna array gain. On the other hand, since the antenna array must be installed on the surface of the mobile platform, it is required to be conformally installed to meet the aerodynamic standards. The microstrip antenna is difficult to conformally install and ensure stable performance due to the limitations of the substrate material. The microstrip antenna substrate material is rigid, making it difficult to closely fit the nose during processing and installation. This causes the stress characteristics of the aircraft to change during flight, affecting the flight speed, attitude and stability of the aircraft. Therefore, there is an urgent need to improve the conformal 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. Under the current restrictions of small aperture and small size conformal installation, it is difficult to achieve continuous high gain and high performance beam scanning characteristics. The dual characteristics of small size and high gain are difficult to reconcile and integrate. SUMMARY

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

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

[0005] As a preferred solution, a plurality of air holes are formed in the dielectric rod along the thickness direction of the dielectric rod, the plurality of air holes are arranged along the length direction of the dielectric rod in sequence, the air holes are circular holes, and the diameter 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 gradually-changing gap is formed between the top side of the loading floor and the lower side of the dielectric rod, and the width of the gradually-changing gap gradually decreases from the suspended end to the connecting end.

[0007] As a preferred solution, one end of the loading floor is arranged flush with one side of the balanced microstrip plate, the other end of the loading floor is an outwardly protruding end, and the horizontal distance between the outwardly protruding end and the suspended end is less than or equal to one fourth of the length of the loading floor.

[0008] As a preferred solution, the coaxial line feeder joint is connected with the outer wall of one side of the balanced microstrip plate, the coaxial line feeder joint comprises a joint body, an inner core strip and a blocking sleeve, the joint body is a cylindrical body, the blocking sleeve is an outer square inner circular sleeve body, the blocking sleeve is sleeved on one end of the joint body close to the balanced microstrip plate, the balanced microstrip plate is connected with the blocking sleeve and the joint body respectively, one end of the inner core strip is arranged in the joint body, and the other end of the inner core strip abuts against the outer wall of one side of the balanced microstrip plate.

[0009] The C-band small-aperture directional radiation surface wave array antenna is composed of the C-band small-aperture directional radiation surface wave antenna units, and comprises a plurality of rows of antenna assemblies 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, the plurality of C-band small-aperture directional radiation surface wave antenna units are arranged in sequence with intervals, a first gap is formed between every two adjacent C-band small-aperture directional radiation surface wave antenna units, the plurality of C-band small-aperture directional radiation surface wave antenna units in the upper row of antenna assemblies and the plurality of C-band small-aperture directional radiation surface wave antenna units in the lower row of antenna assemblies in the two adjacent rows of antenna assemblies are arranged in one-to-one correspondence, and a second gap is formed between one C-band small-aperture directional radiation surface wave antenna unit in the upper row of antenna assemblies and one corresponding C-band small-aperture directional radiation surface wave antenna unit in the lower row of antenna assemblies.

[0010] Each C-band small-aperture directional radiation surface wave antenna unit comprises a coaxial line feeder connector, a balanced microstrip board, a conversion board, a waveguide transmission board, a dielectric rod and a loading floor, the loading floor is a long strip-shaped plate body, the loading floor is horizontally arranged, the balanced microstrip board, the conversion board and the waveguide transmission board are vertically arranged in sequence on the loading floor along the length direction of the loading floor, the balanced microstrip board is a thin plate, the waveguide transmission board is a thick plate, and the conversion board is a gradually changing thickness plate, the thickness of the conversion board gradually decreases from one end close to the waveguide transmission board to the other end away from the waveguide transmission board, one side of the balanced microstrip board is provided with the coaxial line feeder connector, the other side of the balanced microstrip board is connected with one end of the conversion board, the other end of the conversion board is connected with one end of the waveguide transmission board, the other end of the waveguide transmission board is provided with the dielectric rod, one end of the dielectric rod is a connecting end, the connecting end of the dielectric rod is connected with the waveguide transmission board, the other end of the dielectric rod is a suspended end, the width of the dielectric rod gradually decreases from the connecting end to the suspended end, and the longitudinal section shape of the dielectric rod along the central axis in the thickness direction is wedge-shaped.

[0011] The phased array optimization method of the C-band small-aperture directional radiation surface wave array antenna is realized by using the C-band small-aperture directional radiation surface wave array antenna, the phased array optimization method is that when the C-band small-aperture directional radiation surface wave array antenna is composed of a plurality of C-band small-aperture directional radiation surface wave antenna units, the excitation amplitude distribution of the C-band small-aperture directional radiation surface wave array antenna is optimized, the array element pattern obtained by the full-wave simulation software is exported, after the exported array element pattern is multiplied by an array factor, combined with artificial intelligence technology, the array pattern is directly optimized, and the obtained optimization result is compared with a standard index requirement, so that the optimization process of the excitation amplitude distribution of the C-band small-aperture directional radiation surface wave array antenna is completed.

[0012] The C-band small-aperture directional radiation surface wave array antenna has the following beneficial effects:

[0013] 1. The C-band small-aperture directional radiation surface wave antenna unit in the application can realize high gain effect under the condition of small aperture through the antenna unit structure formed by the cooperation between the coaxial line feeder joint, the balanced microstrip board, the conversion board, the waveguide transmission board, the dielectric rod and the loaded floor, synchronously considers the dual characteristics of small aperture and high gain, is less affected by the surrounding environment, is suitable for different installation conditions and installation curved surface structure, improves the emergency response ability of rapid processing, and is suitable for harsh or other rapid reaction use environment.

[0014] 2. The C-band small-aperture directional radiation surface wave array antenna in the application is an array antenna, the structure is reasonably arranged, the antenna pattern can be controlled by an electronic method, the beam scanning function is realized, when in use, the C-band small-aperture directional radiation surface wave array antenna is installed on a support structure conforming to the nose part, and can be attached to any curved surface. The C-band small-aperture directional radiation surface wave array antenna has little influence on the original aerodynamic characteristics of the carrier, is more suitable for application fields of aircrafts, and realizes adaptation to use in emergency or other harsh extreme environments.

[0015] 3. The phased array optimization method of the C-band small-aperture directional radiation surface wave array antenna can optimize the excitation amplitude distribution of the C-band small-aperture directional radiation surface wave array antenna, is beneficial to performance estimation before use and feedback evaluation after use of the C-band small-aperture directional radiation surface wave array antenna, and is beneficial to improving overall 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 DRAWINGS

[0016] Figure 1 It is a first three-dimensional structure schematic view of the C-band small-aperture directional radiation surface wave antenna unit.

[0017] Figure 2 It is a second three-dimensional structure schematic view of the C-band small-aperture directional radiation surface wave antenna unit.

[0018] Figure 3 It is a three-dimensional structure schematic view of the coaxial line feeder joint.

[0019] Figure 4 It is a front view structure schematic view of the C-band small-aperture directional radiation surface wave array antenna, and the C-band small-aperture directional radiation surface wave array antenna shown in the figure is 5*5.

[0020] Figure 5 It is a top view structure schematic view of the C-band small-aperture directional radiation surface wave array antenna, and the C-band small-aperture directional radiation surface wave array antenna shown in the figure is 5*5.

[0021] Figure 6It is a three-dimensional structural schematic diagram of the C-band small-aperture directional radiating surface wave array antenna, and a 5*5 C-band small-aperture directional radiating surface wave array antenna is shown in the figure;

[0022] Figure 7 It is a reflection coefficient and central working frequency gain schematic diagram of the C-band small-aperture directional radiating surface wave antenna unit;

[0023] Figure 8 It is a scanning gain direction schematic diagram of the 1*5 antenna array;

[0024] Figure 9 It is a scanning gain direction schematic diagram of the 5*5 antenna array, and an xoz plane is shown in the figure;

[0025] Figure 10 It is a scanning gain direction schematic diagram of the 5*5 antenna array, and a yoz plane is shown in the figure;

[0026] Figure 11 It is a directional schematic diagram of the equal-amplitude distribution phased array antenna when N=12;

[0027] Figure 12 It is a rectangular coordinate schematic diagram of the amplitude-weighted low-sidelobe array when N=12;

[0028] Figure 13 It is a logic schematic diagram of a traditional optimization method;

[0029] Figure 14 It is a flow schematic diagram of the phased array optimization method in the application.

[0030] In the figure, 1 is a coaxial line feeder connector, 1-1 is a connector body, 1-2 is an inner core strip, 1-3 is a blocking sleeve, 2 is a balanced microstrip board, 3 is a conversion board, 4 is a waveguide transmission board, 5 is a dielectric rod, 5-1 is a suspended end, 5-2 is an air hole, 6 is a loaded floor, 6-1 is an outer convex end, 7 is a gradual change notch, 10 is a C-band small-aperture directional radiating surface wave antenna unit, 11 is a first gap, and 12 is a second gap. DETAILED DESCRIPTION

[0031] The embodiments of the present application are described below through specific concrete examples, and other advantages and effects of the present application can be easily understood by those skilled in the art from the disclosure of the present specification. The present application can also be implemented or applied through other different specific embodiments, and various modifications or changes can be made to the details in the present specification based on different viewpoints and applications without departing from the spirit of the present application.

[0032] Specific embodiment one: combination Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 ,Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 、 Figure 12 、 Figure 13 and Figure 14 The embodiment is described. The embodiment includes a coaxial line feed joint 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-shaped plate body. The loading floor 6 is horizontally arranged. The balanced microstrip plate 2, the conversion plate 3, and the waveguide transmission plate 4 are vertically arranged 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 gradually-changing-thickness plate. The thickness of the conversion plate 3 gradually decreases from one end close to the waveguide transmission plate 4 to the other end away from the waveguide transmission plate 4. The coaxial line feed joint 1 is arranged 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. The other end of the waveguide transmission plate 4 is provided with the 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 plate 4. The other end of the dielectric rod 5 is a suspended end 5-1. The width of the dielectric rod 5 gradually decreases from the connecting end to the suspended end 5-1. The longitudinal section shape of the dielectric rod 5 along the central axis in the thickness direction is a wedge shape. The dielectric rod 5 is a radiation structure. The optimal shape of the longitudinal section of the dielectric rod 5 along the central axis in the thickness direction is an isosceles triangle.

[0033] In the embodiment, the balanced microstrip plate 2 is a plate body with a balanced microstrip line structure. Specifically, the balanced microstrip plate 2 has a microstrip line structure with equal widths of the upper end and the lower end, which plays a role of balanced feeding. The lower end of the balanced microstrip plate 2 is fixedly connected to the loading floor 6. 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. The dielectric substrate is connected to the 50Ω coaxial joint.

[0034] In the 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. 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 adopts a metalized via array, which is beneficial to the formation of the boundary condition of the waveguide.

[0035] In the embodiment, the balanced microstrip plate 2, the conversion plate 3, and the waveguide transmission plate 4 are all hollow plate bodies, which are filled with the same dielectric, facilitating integrated processing. The filling principle and the filling dielectric are both prior art, which are the same as the related filling principle and dielectric of the existing antenna unit.

[0036] The conversion plate 3 in the embodiment is a conversion structure which is linearly tapered from the width of the balanced microstrip plate 2 to the width of the waveguide transmission plate 4, and is linearly or laminated tapered from the thickness of the balanced microstrip plate 2 to the height of the waveguide transmission plate 4, and has a length of 30 mm, so as to realize the impedance matching and mode conversion from the balanced microstrip plate 2 to the waveguide transmission plate 4.

[0037] The medium rod 5 in the embodiment is essentially a radiation structure which is a linearly tapered metal structure extending from the waveguide opening, so as to realize the tapered structure from the waveguide opening to the free space, and to improve the radiation efficiency and reduce the standing wave ratio as an impedance matching structure of the waveguide-free space.

[0038] The loading floor 6 in the embodiment is a bottom support, and provides arrangement positions for the balanced microstrip plate 2, the conversion plate 3, the waveguide transmission plate 4 and the medium rod 5.

[0039] Further, the balanced microstrip plate 2 is a balanced feeding structure, and is connected with the coaxial line feed connector 1. The waveguide transmission plate 4 has a size of 15 mm x 6 mm x 20 mm, and is convenient for integrated processing, and the side wall is wrapped with metal, so as to realize the convenient condition of the waveguide. The conversion plate 3 is linearly tapered from the width of the balanced microstrip plate 2 to the width of the waveguide transmission plate 4, so as to realize the impedance matching and mode conversion from the balanced microstrip plate 2 to the waveguide transmission plate 4.

[0040] Specific embodiment two: the embodiment is a further limitation of the specific embodiment one, and the medium rod 5 is processed with a plurality of air holes 5-2 along the thickness direction thereof. The plurality of air holes 5-2 are sequentially arranged along the length direction of the medium rod 5. The air hole 5-2 is a circular hole, and the hole diameter of the air hole 5-2 is less than or equal to one fifth of the maximum width of the medium rod 5. The above size relationship is the best size processing relationship formed in the processing process, and is beneficial to improve the gain of the antenna unit.

[0041] Further, the medium rod 5 is processed with a plurality of air holes 5-2 along the thickness direction thereof. The arrangement position and the communication performance of the plurality of air holes 5-2 can realize the structure form of the small-aperture traveling wave array. The processing of the air hole 5-2 can better realize the antenna characteristics, and is beneficial to improve the gain of the antenna unit. The necessary structure features of the antenna unit not mentioned in the embodiment are the same as the necessary structure features of the existing antenna unit.

[0042] Specific embodiment three: the embodiment is a further limitation of the specific embodiment one or two. The top side of the loading floor 6 and the lower side of the medium rod 5 form a tapered gap 7 therebetween. The width of the tapered gap 7 decreases sequentially from the suspended end 5-1 to the connecting end. The opening trend and form of the tapered gap 7 are beneficial to match the structure forms of the coaxial line feed connector 1, the balanced microstrip plate 2, the conversion plate 3, the waveguide transmission plate 4, the medium rod 5 and the loading floor 6.

[0043] Specific implementation four: this implementation is further limited to specific implementation one, two or three, one end of the loading floor 6 is arranged flush with one side of the balanced microstrip plate 2, and the other end of the loading floor 6 is an outwardly convex end 6-1. The horizontal distance between the outwardly 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 size relationship is the best size relationship summarized in the modeling and processing process, which is beneficial to improve the gain of the antenna unit. In this implementation, the setting position of the loading floor 6 below the balanced microstrip plate 2, the conversion plate 3, the waveguide transmission plate 4 and the dielectric rod 5 can achieve better impedance and radiation characteristics.

[0044] Specific implementation five: this implementation is further limited to specific implementation one, two, three or four, the coaxial line feed connector 1 is connected to the outer wall of one side of the balanced microstrip plate 2, the coaxial line feed connector 1 includes a connector body 1-1, an inner core strip 1-2 and a blocking sleeve 1-3, the connector body 1-1 is a cylinder, the blocking sleeve 1-3 is an outer square inner circular sleeve body, the blocking sleeve 1-3 is sleeved on the end of the connector body 1-1 close to the balanced microstrip plate 2, the balanced microstrip plate 2 is connected to the blocking sleeve 1-3 and the connector body 1-1, respectively, one end of the inner core strip 1-2 is arranged in the connector body 1-1, and the other end of the inner core strip 1-2 abuts against the outer wall of one side of the balanced microstrip plate 2.

[0045] Further, the coaxial line feed connector 1 can quickly receive signals and reduce signal interference, and is suitable for harsh or other fast response use environments, which can effectively improve the use performance of fast emergency signal receiving.

[0046] Specific implementation six: in combination with 1 to Figure 14 In this implementation, the C-band small-aperture directional radiating surface wave array antenna includes multiple rows of antenna assemblies arranged from top to bottom, each row of antenna assemblies includes multiple C-band small-aperture directional radiating surface wave antenna units 10, the multiple C-band small-aperture directional radiating surface wave antenna units 10 are arranged in sequence with intervals, a first gap 11 is formed between every two adjacent C-band small-aperture directional radiating surface wave antenna units 10, the multiple C-band small-aperture directional radiating surface wave antenna units 10 in the upper row of antenna assemblies and the multiple C-band small-aperture directional radiating surface wave antenna units 10 in the lower row of antenna assemblies are arranged in one-to-one correspondence, and a second gap 12 is formed between one C-band small-aperture directional radiating surface wave antenna unit 10 in the upper row of antenna assemblies and one corresponding C-band small-aperture directional radiating surface wave antenna unit 10 in the lower row of antenna assemblies.

[0047] Each C-band small-aperture directional radiation surface wave antenna unit 10 comprises a coaxial line feeder joint 1, a balanced microstrip board 2, a conversion board 3, a waveguide transmission board 4, a dielectric rod 5 and a loading floor 6, the loading floor 6 is a long strip-shaped plate body, the loading floor 6 is horizontally arranged, the balanced microstrip board 2, the conversion board 3 and the waveguide transmission board 4 are vertically arranged on the loading floor 6 along the length direction of the loading floor 6 in sequence, the balanced microstrip board 2 is a thin plate, the waveguide transmission board 4 is a thick plate, the conversion board 3 is a gradually changing thickness plate, the thickness of the conversion board 3 gradually decreases from one end close to the waveguide transmission board 4 to the other end away from the waveguide transmission board 4, one side of the balanced microstrip board 2 is provided with the coaxial line feeder joint 1, the other side of the balanced microstrip board 2 is connected with one end of the conversion board 3, the other end of the conversion board 3 is connected with one end of the waveguide transmission board 4, the other end of the waveguide transmission board 4 is provided with the dielectric rod 5, one end of the dielectric rod 5 is a connecting end, the connecting end of the dielectric rod 5 is connected with 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 gradually decreases from the connecting end to the suspended end 5-1, and the optimal shape of the longitudinal section along the central axis of the thickness direction of the dielectric rod 5 is an isosceles triangle.

[0048] The coaxial line feeder joint 1 in the embodiment comprises a joint body 1-1, an inner core strip 1-2 and a blocking sleeve 1-3, the joint body 1-1 is a cylinder, the blocking sleeve 1-3 is an outer square inner circular sleeve body, the blocking sleeve 1-3 is sleeved on the joint body 1-1 at one end close to the balanced microstrip board 2, the balanced microstrip board 2 is connected with the blocking sleeve 1-3 and the joint body 1-1 respectively, one end of the inner core strip 1-2 is arranged in the joint body 1-1, and the other end of the inner core strip 1-2 abuts against one side of the outer wall of the balanced microstrip board 2. The coaxial line feeder joint 1 can quickly receive signals, reduce signal interference, is suitable for harsh or other fast response use environments, and can effectively improve the use performance of fast emergency signal receiving.

[0049] The balanced microstrip board 2 in the embodiment is a balanced feeding structure, the balanced microstrip board 2 is connected with the coaxial line feeder joint 1, the size of the waveguide transmission board 4 is 15mm*6mm*20mm, which is convenient for integrated processing, the side wall is wrapped with metal, the convenient condition of the waveguide can be realized, the conversion board 3 is linearly gradually changed in width from the width of the balanced microstrip board 2 to the width of the waveguide transmission board 4, so that the impedance matching and mode conversion of the balanced microstrip board 2 to the waveguide transmission board 4 are realized.

[0050] The conversion board 3 in the embodiment is a conversion structure, which is linearly gradually changed in width from the width of the balanced microstrip board 2 to the width of the waveguide transmission board 4, is linearly or laminated gradually changed in thickness from the thickness of the balanced microstrip board 2 to the height of the waveguide transmission board 4, and has a length of 30mm, so that the impedance matching and mode conversion of the balanced microstrip board 2 to the waveguide transmission board 4 are realized.

[0051] The optimal length of the waveguide transmission plate 4 is 20mm, the optimal height of the waveguide transmission plate 4 is 15mm, and the optimal thickness of the waveguide transmission plate 4 is 6mm. The sidewall of the waveguide transmission plate 4 is wrapped with metal or adopts a metalized via array, which is beneficial to the formation of the boundary condition of the waveguide.

[0052] In the embodiment, the medium rod 5 is essentially a radiation structure composed of a linearly tapered metal extending from the waveguide aperture, which realizes a tapered structure from the waveguide aperture to free space, serves as an impedance matching structure of the waveguide-free space, improves the radiation efficiency, and reduces the standing wave ratio. The medium rod 5 is processed with a plurality of air holes 5-2 along the thickness direction thereof, the plurality of air holes 5-2 are sequentially arranged along the length direction of the medium rod 5, the air holes 5-2 are circular holes, and the hole diameter of the air holes 5-2 is less than or equal to one fifth of the maximum width of the medium rod 5. The above size relationship is the optimal size processing relationship formed in the processing process, which is beneficial to improving the gain of the antenna unit.

[0053] In the embodiment, the balanced microstrip plate 2, the conversion plate 3, and the waveguide transmission plate 4 are all hollow plate bodies, and the interiors are filled with the same medium, which is beneficial to integrated processing. The filling principle and the filling medium are both prior art, and the same as the related filling principle and medium of the existing antenna unit.

[0054] In the embodiment, the loading floor 6 serves as a bottom support and provides arrangement positions for the balanced microstrip plate 2, the conversion plate 3, the waveguide transmission plate 4, and the medium rod 5.

[0055] In the embodiment, a tapered notch 7 is formed between the top side of the loading floor 6 and the lower side of the medium rod 5, the width of the tapered notch 7 decreases from the overhanging end 5-1 to the connecting end, and the opening trend and form of the tapered notch 7 are beneficial to matching the structure forms of the coaxial line connector 1, the balanced microstrip plate 2, the conversion plate 3, the waveguide transmission plate 4, the medium rod 5, and the loading floor 6.

[0056] In the embodiment, one end of the loading floor 6 is arranged flush with one side of the balanced microstrip plate 2, and the other end of the loading floor 6 is an outwardly convex end 6-1, and the horizontal distance between the outwardly convex end 6-1 and the overhanging end 5-1 is less than or equal to one fourth of the length of the loading floor 6. The above size relationship is the optimal size relationship formed in the modeling and processing process, which is beneficial to improving the gain of the antenna unit. In the embodiment, the arrangement position of the loading floor 6 below the balanced microstrip plate 2, the conversion plate 3, the waveguide transmission plate 4, and the medium rod 5 can achieve better impedance and radiation characteristics.

[0057] Specific implementation method seven: combination Figures 1 to 14The phased array optimization method in the embodiment is used for optimizing 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 a plurality of C-band small-aperture directional radiation surface wave antenna units 10. The array element pattern obtained by full-wave simulation software is exported. After the exported array element pattern is multiplied by an array factor, the array element pattern is directly optimized by combining artificial intelligence technology. The obtained optimization result is compared with a standard index requirement, so that the optimization process of the excitation amplitude distribution of the C-band small-aperture directional radiation surface wave array antenna is completed.

[0058] In the embodiment, the width of the medium rod 5 decreases from one end close to the waveguide transmission plate 4 to the other end away from the waveguide transmission plate 4. The medium rod 5 is a directional radiation antenna composed of an elongated medium rod, the gain of which is positively correlated with the longitudinal length of the medium rod. The high-gain characteristic can be realized under the limitation of a small aperture, and the medium rod can be integrally processed by using mechanical, electronic, and 3D printing processing technologies, so that the medium rod can be conformally installed under the condition of ensuring stable performance.

[0059] The medium rod antenna is used as a phased array unit for the first time in the application. A plurality of matching structures are used to realize the high-gain directional radiation characteristic under the limitation of a small aperture, so that the gain of the antenna unit is significantly improved. In addition, the loading floor 6, specifically a metal floor, is loaded on one side of the wide side of the antenna, so that the impedance and radiation characteristics can be better realized.

[0060] The structure size of the C-band small-aperture directional radiation surface wave antenna unit in the application can be made into different specifications according to specific requirements, and the specifications are 15 mm, 6 mm, and 160 mm. The working frequency band is 5.8-7.0 GHz. The typical standing wave ratio in the frequency band is less than 2, and the minimum value is 1.0. The directional radiation gain at a typical working frequency point 6.4 GHz in the band is 9.35 dBi.

[0061] The optimal sizes of the balanced microstrip plate 2, the conversion plate 3, the waveguide transmission plate 4, the medium rod 5, and the loading floor 6 in the cooperation process are as follows:

[0062] 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 medium rod 5 is 80 mm. The length of the loading floor 6 is 160 mm. The maximum thickness of the conversion plate 3, the thicknesses of the waveguide transmission plate 4 and the medium rod 5 are all 6 mm. The maximum widths of the balanced microstrip plate 2, the conversion plate 3, the waveguide transmission plate 4, and the medium rod 5 are all 15 mm.

[0063] Specific embodiment seven: the C-band small aperture directional radiating surface wave antenna unit in the application needs to be excited for optimization of the amplitude distribution to improve the electrical performance of the antenna after being composed into an array antenna, and the application proposes a phased array optimization method by introducing the radiation influence of the array element.

[0064] In combination Figures 1 to 14 As shown in the drawings, the C-band small aperture directional radiating surface wave antenna unit in the application can realize one-dimensional beam scanning function under the condition of space limitation, and here, a 1x5 array is taken as an example, the antenna unit spacing is selected as 18 mm, and the dielectric rod antenna unit is composed into a 1x5 array. By controlling the feed phase to change from-60° to 60°, the beam scanning function in the range of ±20° in the one-dimensional plane can be realized, and the gain is greater than 9.5 dBi. Through the simulation of the gain curve of the antenna with the frequency change, the overall gain of the antenna is greater than 13.5 dBi.

[0065] In combination Figure 8 , Figure 9 and Figure 10 As shown in the drawings, the C-band small aperture directional radiating surface wave array antenna in the application can realize two-dimensional beam scanning function under the condition of space limitation, and here, a 5x5 array is taken as an example, the array x-direction spacing is selected as 22.5 mm, and the y-direction spacing is selected as 18 mm. In combination with the structural size of the antenna unit, the aperture size of the antenna array is: 105 mm in the x-direction and 78 mm in the y-direction. When the changing phase is-60 to 60°, the scanning range of the phased array antenna in the xoz plane and the yoz plane can be ±20°, and the overall gain is higher than 16 dBi.

[0066] In the application, for the radiation field of the phased array antenna, the commonly used methods to obtain the low side lobe of the radiation pattern include amplitude weighting, phase weighting and density weighting.

[0067] Among them, the amplitude weighting is to control the feed amplitude of each unit to realize the low side lobe of the radiation field of the phased array antenna. A large number of analytical methods and engineering optimization algorithms have appeared for the research on the amplitude weighting control side lobe technology, such as Taylor synthesis method and Chebyshev synthesis method. However, the amplitude weighting makes each unit of the phased array antenna connect different weight attenuators, which greatly increases the cost and complexity of the system.

[0068] In addition, the phase weighting is to control the feed phase of each unit to realize the low side lobe of the radiation field of the phased array antenna. However, the effect of phase weighting in realizing the low side lobe is limited, and it is difficult to obtain better low side lobe performance indicators only by phase weighting. Moreover, phase weighting cannot be used to realize the low side lobe of the radiation field.

[0069] In addition, the density weighting is divided into two kinds, specifically:

[0070] 1) One is an equal-amplitude unequal-interval array, that is, the elements in the array are symmetrical with the middle element, and the element interval from the array to the array edge increases in turn. However, the resulting irregular element interval of the radiation array brings great difficulties to the engineering implementation of the array structure design, heat dissipation design, and process processing.

[0071] 2) The other is an equal-amplitude equal-interval sparse array, that is, whether the antenna element exists in the array grid is determined according to a certain rule, thereby forming a sparse arrangement of the phased array antenna to achieve the purpose of low sidelobe. Compared with the full array with the same aperture, the sparse array has almost the same main lobe width, has a narrower main lobe and higher resolution relative to the number of elements, and has a lower cost than the full array, so it is well applied to large phased array antennas.

[0072] The present application selects 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 principle of pattern multiplication, that is, the total array pattern is equal to the product of the element pattern and the array factor. The current phased array antenna optimization process focuses on the array factor synthesis angle, and the element pattern is regarded as the omnidirectional radiation of an ideal point source, so that there is a deviation between the actual array pattern obtained by this method and the optimization result, especially when the maximum radiation direction of the element pattern exists. This phenomenon is more obvious. This makes it difficult to meet the index requirements when the neural network and other phased array antenna optimization design methods are applied.

[0073] The present application first introduces the influence of the element pattern into the phased array optimization process, exports the element pattern obtained by the full-wave simulation software, and multiplies it with the array factor. Combined with artificial intelligence technology, the array pattern is directly optimized, and the optimization result meets the index requirements. Compared with the existing optimization scheme, this method has a simpler optimization process, can be optimized according to the radiation characteristics of the element antenna, and can further improve the performance of the antenna.

[0074] Combined with Figure 13 and Figure 14 As shown in the figures, the comparison results of the optimization method of the present application and the traditional method show that there is a great difference in the radiation field of the antenna before and after introducing the influence of the element pattern. The array factor is optimized by using the traditional existing optimization method to meet the index requirements, and there is a great deviation between the result and the index after introducing the actual element. The optimization method proposed in the present application directly optimizes the array pattern, and the result shows that the optimization method of the present application fully meets the index requirements and reduces the related difficulty in the optimization process.

Claims

1. A C-band small aperture directional radiating surface wave antenna unit, characterized by: The coaxial line feeder joint (1), the balanced microstrip plate (2), the conversion plate (3), the waveguide transmission plate (4), the dielectric rod (5) and the loading floor (6) are included, the loading floor (6) is a long strip-shaped plate body, the loading floor (6) is horizontally arranged, the balanced microstrip plate (2), the conversion plate (3) and the waveguide transmission plate (4) are sequentially vertically arranged on the loading floor (6) 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 gradually changing thickness plate, the thickness of the conversion plate (3) sequentially decreases from one end close to the waveguide transmission plate (4) to the other end away from the waveguide transmission plate (4), one side of the balanced microstrip plate (2) is provided with the coaxial line feeder joint (1), the other side of the balanced microstrip plate (2) is connected with one end of the conversion plate (3), the other end of the conversion plate (3) is connected with one end of the waveguide transmission plate (4), the other end of the waveguide transmission plate (4) is provided with the dielectric rod (5), one end of the dielectric rod (5) is a connecting end, the connecting end of the dielectric rod (5) is connected with 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) sequentially decreases from the connecting end to the suspended end (5-1), the longitudinal section shape of the dielectric rod (5) along the central axis in the thickness direction is a wedge shape; a gradually changing gap (7) is formed between the top side of the loading floor (6) and the lower side of the dielectric rod (5), the width of the gradually changing gap (7) sequentially decreases from the suspended end (5-1) to the connecting end.

2. The C-band small-aperture directional radiating surface wave antenna unit of claim 1, wherein: The dielectric rod (5) is processed with a plurality of air holes (5-2) in the thickness direction, the plurality of air holes (5-2) are sequentially arranged along the length direction of the dielectric rod (5), the air hole (5-2) is a circular hole, the hole diameter of the air hole (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 radiating surface wave antenna unit of claim 1, wherein: One end of the loading floor (6) is flush with one side of the balanced microstrip plate (2), the other end of the loading floor (6) is an outwardly convex end (6-1), the horizontal distance between the outwardly convex end (6-1) and the suspended end (5-1) is less than or equal to one fourth of the length of the loading floor (6).

4. The C-band small-aperture directional radiating surface wave antenna unit of claim 1, wherein: The coaxial line feeder joint (1) is connected with the outer wall of one side of the balanced microstrip plate (2), the coaxial line feeder joint (1) includes a joint body (1-1), an inner core strip (1-2) and a retaining sleeve (1-3), the joint body (1-1) is a cylinder, the retaining sleeve (1-3) is an outer square inner circular sleeve body, the retaining sleeve (1-3) is sleeved on one end of the joint body (1-1) close to the balanced microstrip plate (2), the balanced microstrip plate (2) is connected with the retaining sleeve (1-3) and the joint body (1-1) respectively, one end of the inner core strip (1-2) is arranged in the joint body (1-1), the other end of the inner core strip (1-2) abuts against the outer wall of one side of the balanced microstrip plate (2).

5. A C-band small-aperture directional radiating surface wave array antenna, which is composed of the C-band small-aperture directional radiating surface wave antenna unit according to any one of claims 1 to 4, characterized in that: The application relates to a phased array optimization method for a C-band small-aperture directional radiating surface wave array antenna.

6. A phased array optimization method for a C-band small-aperture directional radiating surface wave array antenna, implemented by the C-band small-aperture directional radiating surface wave array antenna of claim 5, characterized in that: The phased array optimization method is used for optimizing the excitation amplitude distribution of the C-band small-aperture directional radiating surface wave array antenna when the C-band small-aperture directional radiating surface wave array antenna is formed by a plurality of C-band small-aperture directional radiating surface wave antenna units (10). The element pattern obtained by full-wave simulation software is exported. After the exported element pattern is multiplied by an array factor, the array direction pattern is directly optimized by combining an artificial intelligence technology. The obtained optimization result is compared with a standard index requirement, so that the optimization process of the excitation amplitude distribution of the C-band small-aperture directional radiating surface wave array antenna is completed.

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