Performance optimization method of rectangular horn antenna and rectangular horn antenna

Abstract

The invention provides a performance optimization method of a rectangular horn antenna and the rectangular horn antenna, and the performance optimization method comprises the steps: firstly adding a matching section, designing the matching end of the horn antenna into a multi-step structure, achieving the effect of reducing the side lobe of an E surface, then adjusting the length of a third step to change the phase difference between a TM12 mode and a TM10 mode, and achieving the effect of reducing the side lobe of the E surface. The side lobe is further reduced, and the ridge of the inner circumferential wall of the field angle radiation section is chamfered to suppress cross polarization. On the premise of keeping the inherent advantages of simple structure, convenience in processing, broadband operation and the like to the greatest extent, the radiation characteristics of the antenna are optimized in a collaborative manner fundamentally, and particularly, troubling D-plane cross polarization is effectively inhibited, and the side lobe level is reduced; therefore, the extreme requirements of a next-generation high-performance communication system on antenna polarization purity and directional diagram quality are met.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, and more specifically, relates to a performance optimization method for a rectangular horn antenna and the rectangular horn antenna itself. Background Technology

[0002] In modern millimeter-wave wireless communication, satellite link, and radar systems, the requirements for antenna performance have reached their limits. Not only are high gain and wide bandwidth required, but stringent standards are also imposed on the purity of the radiation pattern, with low cross-polarization levels and low sidelobe levels being particularly crucial indicators. Horn antennas are often chosen due to their relatively simple structure, good directivity, and high power capacity. However, their inherent design limitations are becoming increasingly apparent in high-end applications: traditional rectangular or pyramidal horns, due to the asymmetry of the E-plane and H-plane field distribution and phase center, produce high cross-polarization radiation in directions away from the principal plane (especially the D-plane at 45°). This defect directly translates into co-channel interference in dual-polarized or polarization-multiplexed systems, severely degrading polarization isolation and limiting system capacity and spectral efficiency. Simultaneously, high sidelobes caused by aperture field abrupt changes and edge diffraction effects can unintentionally receive or radiate interference signals, reducing spatial selectivity and potentially exacerbating mutual coupling problems in multi-antenna systems. To address these challenges, existing technologies often fall into a dilemma between performance and complexity: for example, while using multi-mode, hybrid-mode, or corrugated horn structures can improve performance, it comes at the cost of structural simplicity, operating bandwidth, and manufacturing cost, making the antenna bulky and expensive; while using external devices such as chokes and metal grids to suppress sidelobes significantly increases the profile size and may introduce new resonant modes. In addition, some tuning methods based on local shape optimization have limited improvement effects and often sacrifice some aspects, making it difficult to achieve synergistic suppression of cross-polarization and sidelobes, and may even worsen impedance matching. Summary of the Invention

[0003] The purpose of this invention is to provide a performance optimization method for a rectangular horn antenna and a rectangular horn antenna in order to solve the technical problem that existing horn antennas are difficult to achieve coordinated suppression of cross polarization and sidelobes.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a rectangular horn antenna, comprising the following steps: A horn antenna is provided, comprising a feed conversion section and an angular radiating section connected in sequence. The end of the feed conversion section away from the angular radiating section is a rectangular waveguide, and the other end of the feed conversion section is a feed port. The radiating aperture of the angular radiating section is rectangular. A matching section is designed between the feed conversion section and the angular radiation section, and the matching section is designed as a multi-level stepped structure to achieve TM10 Introducing TM based on the pattern 12 In this mode, the dimension of the multi-level stepped structure near the end of the feed conversion section is smaller than the dimension near the end of the angular radiation section; Determine TM 12 The ideal energy ratio of the mode is determined, and the number of stages of the multi-stage ladder structure is determined based on the ideal energy ratio to realize TM. 12 The actual energy percentage of the mode, while reducing the sidelobes of the E-plane; Adjusting the length of the third step alters the actual energy percentage, bringing it closer to the ideal energy percentage, while simultaneously changing TM. 12 Pattern and TM 10 Phase difference between modes to further reduce sidelobes on the E plane; The edges of the inner peripheral wall of the angular radiation segment are chamfered to suppress cross-polarization; Adjust the angle and size of the chamfer to further suppress cross-polarization.

[0005] Optionally, the number of stages in the multi-stage ladder structure is determined based on the ideal energy ratio to achieve TM. 12 The actual energy percentage of the mode, while reducing the sidelobes of the E-plane, includes the following steps: TM 12 The mode, under the stated actual energy percentage, TM 12 Far-field pattern filling TE of the mode 10 The first null of the far-field pattern of the mode causes the first sidelobe of the E-plane to merge with the main lobe, thereby reducing the sidelobes of the E-plane.

[0006] Optionally, the ideal energy percentage is 10% to 14%, the number of stages in the multi-stage ladder structure is 3, and the actual energy percentage is 20% to 26%.

[0007] Optionally, the length of the third step is 8 mm to 13.2 mm, and the phase difference is 16 to 20 degrees.

[0008] Optionally, in TM 10 Introducing TM based on the pattern 12 The steps of the pattern also introduce x The first electric field component in the direction is introduced in the step of chamfering the edge of the inner peripheral wall of the angular radiation segment. x The second electric field component is in the direction of the first electric field component and the second electric field component, and the directions of the first electric field component and the second electric field component are opposite to those of the first electric field component, so as to suppress cross-polarization.

[0009] Optionally, the angle and size of the chamfer can be adjusted according to the magnitude of the first electric field component.

[0010] This invention also provides a rectangular horn antenna using the aforementioned performance optimization method. The rectangular horn antenna includes a feed conversion section, a matching section, and an angular radiation section connected in sequence. The end of the feed conversion section away from the matching section is a rectangular waveguide, and the other end of the feed conversion section is a feed port. The matching section has a multi-stage stepped structure, and the size of the matching section gradually increases from the feed conversion section to the angular radiation section. The multi-stage stepped structure is used to excite higher-order modes to reduce sidelobes. The radiating aperture of the angular radiation section is rectangular, and the edges of the inner peripheral wall of the angular radiation section have a chamfered structure. The chamfered structure is used to suppress cross-polarization.

[0011] Optionally, the resonant mode of the rectangular horn antenna is TM. 10 Pattern and TE 12 The composite mode of the mode, wherein the higher-order mode is TE 12 model.

[0012] Optionally, the number of stages in the multi-stage ladder structure is 3.

[0013] Optionally, the chamfered structure has an angle of 45 degrees and a bevel length of 2.8 mm to 3 mm.

[0014] The performance optimization method for rectangular horn antennas and the beneficial effects of rectangular horn antennas provided by this invention are as follows: Compared with the prior art, the performance optimization method for rectangular horn antennas of this invention first adds a matching section and designs the matching end of the horn antenna as a multi-level stepped structure, in TM 10 Introducing TM based on the pattern 12 Pattern, according to TM 12 The ideal energy ratio of the mode determines the number of stages in the multi-step structure, achieving the effect of reducing the sidelobes of the E-plane. Then, adjusting the length of the third step changes the TM. 12 Pattern and TM 10 The phase difference between modes further reduces sidelobes, and the edges of the inner peripheral wall of the angular radiation segment are chamfered to suppress cross-polarization. While maintaining its inherent advantages such as simple structure, convenient manufacturing, and wide bandwidth operation to the maximum extent, this invention fundamentally and synergistically optimizes its radiation characteristics, particularly effectively suppressing troublesome D-plane cross-polarization and reducing sidelobe levels, thereby meeting the extreme requirements of next-generation high-performance communication systems for antenna polarization purity and pattern quality. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A step diagram illustrating the performance optimization method for a rectangular horn antenna provided in an embodiment of the present invention; Figure 2 A three-dimensional structural diagram of a rectangular horn antenna provided in an embodiment of the present invention; Figure 3 A cross-sectional view of a rectangular horn antenna provided in an embodiment of the present invention; Figure 4 The right view of the rectangular horn antenna provided in an embodiment of the present invention; Figure 5 This is an electric field distribution diagram at the radiation aperture provided in an embodiment of the present invention; Figure 6 The radiation pattern of the E-plane of the radiation port provided in an embodiment of the present invention; Figure 7 The number of levels and TM of the multi-level ladder structure provided in the embodiments of the present invention 12 The relationship between the proportion of patterns and frequency; Figure 8 The relationship between the length of the third-level step and the phase difference and the actual energy ratio, as well as the relationship between phase change and sidelobe change, are provided in the embodiments of the present invention. Figure 9 Electric field distribution diagrams of the radiation aperture before and after the addition of the chamfer structure, provided for embodiments of the present invention; Figure 10 The relationship between the angle and bevel length of the chamfered structure and the cross-polarization provided in the embodiments of the present invention; Figure 11 The relationship between the bevel length of the chamfered structure provided in the embodiments of the present invention and the gain and sidelobes.

[0017] The following are the labeling elements in the figure: 10 - Power supply conversion section; 20 - Matching section; 21 - Third-level step; 30 - Angle radiation section; 31 - Chamfered structure. Detailed Implementation

[0018] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0019] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0020] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0022] As described in the background section, conventional performance optimization methods for horn antennas have limited improvement effects and often sacrifice some aspects, making it difficult to achieve coordinated suppression of cross-polarization and sidelobes, and may even worsen impedance matching.

[0023] To address this, the present invention proposes a performance optimization method for rectangular horn antennas and a rectangular horn antenna itself. This method not only maintains the inherent advantages of horn antennas, such as simple structure, convenient processing, and wide bandwidth operation, but also fundamentally optimizes their radiation characteristics in a synergistic manner. In particular, it effectively suppresses planar cross-polarization and reduces sidelobe levels to meet the extreme requirements of next-generation high-performance communication systems for antenna polarization purity and pattern quality.

[0024] Before describing the embodiments of the present invention, sidelobe level and cross-polarization are first defined and explained.

[0025] Sidelobe level: Sidelobe level refers to the ratio of the maximum intensity of the side lobes (or sidelobes) other than the main lobe (the direction of strongest radiation) in the antenna radiation pattern to the maximum intensity of the main lobe, usually expressed in decibels (dB). The lower the SLL (the larger the negative dB value), the more concentrated the energy is in the main lobe. To optimize antenna performance, it is necessary to reduce the sidelobe level. The sidelobe closest to the main lobe is called the first sidelobe, the second closest is called the second sidelobe, and so on.

[0026] Cross-polarization: Cross-polarization level (XPL) refers to the magnitude of an unwanted polarization component orthogonal to the main polarization that is generated in the same direction when an antenna radiates (or receives) its designed main polarization wave. It is usually expressed as the ratio (dB) of the cross-polarization component to the main polarization component. The lower the XPL, the stronger the antenna's ability to maintain pure polarization. Cross-polarization is a relative concept; for example, the cross-polarization corresponding to horizontal polarization is vertical polarization, and the cross-polarization corresponding to right-hand circular polarization is left-hand circular polarization. To optimize antenna performance, cross-polarization needs to be reduced.

[0027] The rectangular horn antenna provided in the embodiments of the present invention will now be described.

[0028] Please refer to the following: Figures 1 to 4 The performance optimization method for rectangular horn antennas includes the following steps: S10: A horn antenna is provided, including a feed conversion section 10 and an angular radiation section 30 connected in sequence. The end of the feed conversion section 10 away from the angular radiation section 30 is a rectangular waveguide, and the other end of the feed conversion section 10 is a feed port. The radiation port surface of the angular radiation section 30 is rectangular. S20: A matching section 20 is designed between the feed conversion section 10 and the angular radiation section 30, and the matching section 20 is designed as a multi-level stepped structure to achieve the desired effect in TM. 10 Introducing TM based on the pattern 12 In this pattern, the dimension of the multi-stage stepped structure near the feed conversion section 10 is smaller than the dimension near the angular radiation section 30. S30: Determine TM 12 The ideal energy ratio of the model is determined, and the number of stages in the multi-level ladder structure is determined based on the ideal energy ratio to achieve TM. 12 The actual energy percentage of the mode, while reducing the sidelobes of the E-plane; S40: Adjust the length of the third step 21 to change the actual energy ratio, making the actual energy ratio closer to the ideal energy ratio, and at the same time change TM. 12 Pattern and TM 10 Phase difference between modes to further reduce sidelobes on the E plane; S50: Chamfer the edges of the inner peripheral wall of the angular radiation segment 30 to suppress cross-polarization; S60: Adjust the angle and size of the chamfer to further suppress cross-polarization.

[0029] In step S10, the radiating aperture of the horn antenna is rectangular; such antennas are all called rectangular horn antennas. The feed transition section 10 gradually transitions the rectangular waveguide to the feed port of the horn antenna. The feed transition section 10 mainly serves to smooth the structural transition, reduce port reflection, and expand the reflection coefficient bandwidth. The angular radiation section 30 is used to ensure the smooth transmission of electromagnetic waves into free space and reduce impedance discontinuities at the interface with free space.

[0030] In step S20, adding a matching segment 20 with a multi-level stepped structure can appropriately excite higher-order modes (TM). 12 This can optimize the uniform field distribution in the y-direction into a gradually varying field distribution, thereby reducing the sidelobes of the E-plane. Specifically, without designing the matching segment 20, the resonant mode at the radiating aperture is TM. 10 Adding a matching segment 20 to the multi-level stepped structure will introduce higher-order modes (TM). 12 ),TM 10 and TM 12 The elements overlap and change the resonance mode. The multi-stage stepped structure consists of multiple stepped structures connected in sequence. Since this invention is a rectangular horn antenna, the cross-section of each stepped structure is also rectangular, and the size of each stepped structure gradually increases along the electromagnetic wave propagation direction, with the stepped structure closest to the angular radiation segment 30 having the largest size.

[0031] In step S30, both the ideal energy percentage and the actual energy percentage are TM. 12 Model Energy and Total Energy (TM) 12 Mode energy and TM 10 The percentage of the sum of the energy of the modes. The TM can be determined based on numerical calculations. 12 The ideal energy ratio of the mode can greatly reduce the sidelobes of the E plane. However, the actual energy ratio that can be achieved by simply changing the number of stages in the multi-stage step structure cannot be exactly the same as the ideal energy ratio, so the ideal sidelobe suppression effect cannot be achieved. In order to further improve the sidelobe suppression effect, the length of the third-stage step 21 is adjusted in step S40.

[0032] In step S40, adjusting the length of the third step 21 not only allows for fine adjustment of the higher-order mode TM 12 The actual energy percentage of the mode will also change the higher-order mode™ 12 Mode and main mode TE 10 The phase difference of the mode (vector synthesis must consider both amplitude (energy ratio) and phase) is used to achieve precise reduction of sidelobes. The step closest to the feed conversion section 10 is the first step, and the step closest to the angular radiation section 30 is the third step 21.

[0033] In step S50, the edges of the inner peripheral wall of the angular radiation segment 30 are chamfered to form a chamfered structure 31 (see [link]). Figure 4 This reduces cross-polarization by altering the electric field distribution near the edge.

[0034] In step S60, by adjusting the angle and size of the chamfer, a better cross-polarization suppression effect can be achieved.

[0035] The performance optimization method for the rectangular horn antenna in the above embodiments first adds a matching segment 20 and designs the matching end of the horn antenna as a multi-level stepped structure, in TM 10 Introducing TM based on the pattern 12 Pattern, according to TM 12 The ideal energy ratio of the mode determines the number of stages in the multi-step structure, achieving the effect of reducing the sidelobes of the E-plane. Then, adjusting the length of the third step 21 changes the TM. 12 Pattern and TM 10 The phase difference between modes further reduces sidelobes, and the edges of the inner peripheral wall of the angular radiation segment 30 are chamfered to suppress cross-polarization. While maintaining its inherent advantages such as simple structure, convenient processing, and wide bandwidth operation to the maximum extent, this invention fundamentally and synergistically optimizes its radiation characteristics, particularly effectively suppressing troublesome D-plane cross-polarization and reducing sidelobe levels, thereby meeting the extreme requirements of next-generation high-performance communication systems for antenna polarization purity and pattern quality.

[0036] It should be noted that the rectangular horn antenna is made of metal, or has a metal layer coated on the surfaces (inner and outer surfaces) of a non-structural structure. All dimensions mentioned in this invention refer to the internal dimensions of the rectangular horn antenna, not its external dimensions.

[0037] In some embodiments of the present invention, please refer to Figure 5 and Figure 6 The number of stages in the multi-stage ladder structure is determined based on the ideal energy ratio to achieve TM. 12 The actual energy percentage of the mode, while reducing the sidelobes of the E-plane, includes the following steps: TM 12 In terms of actual energy percentage, TM 12 Far-field pattern filling TE of the mode 10 The first null of the far-field pattern of the mode causes the first sidelobe of the E-plane to merge with the main lobe, thereby reducing the sidelobes of the E-plane.

[0038] Specifically, please refer to Figure 5 TE 10 The electric field of the mode along x The directional field has a gradually changing distribution (larger in the middle and smaller at the edges), so the sidelobes of the radiation pattern in this direction (H-plane) are relatively low, while along...y Direction TE 10 The electric field amplitude of the mode is uniformly distributed, resulting in relatively large sidelobes in the radiation pattern on the E-plane. Therefore, we need to introduce a suitable higher-order mode TM. 12 When the energy ratio of the higher-order mode is the ideal energy ratio, it is possible to... y The electric field amplitude in the direction also forms an approximately gradually varying distribution. See further details. Figure 6 Based on the principle of far-field pattern vector superposition, Figure 6 TE is given 10 Pattern and TM 12 The far-field radiation pattern of the model and the result of its vector superposition can be approximated from numerical calculations, showing that TM 12 The far-field pattern of the mode can perfectly fill the TE. 10 The first zero point of the mode results in a wider main lobe range and smaller side lobes (the original main lobe and the first side lobe merge, and the second side lobe becomes the new first side lobe). Based on the above analysis, we can know that appropriate excitation and a suitable proportion of TM... 12 The mode (ideal energy ratio) can reduce the sidelobe of the E-plane.

[0039] In some embodiments of the present invention, please refer to Figures 5 to 7 Ideally, the energy percentage is 10% to 14%, but with a multi-tiered structure having three levels, the actual energy percentage is 20% to 26%. Please refer to [link / reference]. Figure 7 , Figure 7 The relationship between the matching segments 20 of different levels and the actual energy proportion as a function of frequency is shown. Structure I is a two-level stepped structure, Structure II is a three-level stepped structure, Structure III is a four-level stepped structure, and Structure IV is a five-level stepped structure. From... Figure 7 It can be seen that when the number of stages in the multi-stage ladder structure is 3, the actual energy ratio is 20% to 26%, which is closer to the ideal energy ratio (10% to 12%) compared to other stages. Therefore, the number of stages in the multi-stage ladder structure is designed to be 3, and the matching segment 20 adopts structure II.

[0040] In some embodiments, TM 12 The ideal energy ratio for this model is 12.8%.

[0041] In some embodiments of the present invention, please refer to Figure 3 and Figure 8 The length of the third step 21 ranges from 8 mm to 13.2 mm, with a phase difference of 16 to 20 degrees. The length of the third step 21 is... L ph2 The phase difference is TM. 12 Pattern and TE 10 The phase difference of the pattern. The applicant for different lengths...L ph2 Simulations were performed, and the simulation results are as follows: Figure 8 , Figure 8 In Figure (a), the relationship between the length of the third step 21, the phase difference, and the actual energy percentage is shown. L ph2 When the length is 8mm to 13.2mm, TM 12 The actual energy share of the model remains within a low range, third step 21 L ph2 After the length exceeds 14mm, TM 12 The actual energy ratio of the model will increase significantly, and the difference from the ideal energy ratio will become increasingly larger; Figure 8 In Figure (b), the relationship between phase change and sidelobe change is shown. When the phase difference is about 18 degrees, the sidelobe is significantly suppressed more effectively.

[0042] It should be noted that in the simulation model used above, the radiation aperture is a square with an inner side length of 25mm, the inner side length of the first step is 10.09mm, the inner side length of the second step is 13.67mm, and the inner side length of the third step 21 is 16.19mm.

[0043] In some embodiments, the length of the third step 21 is 9.58 mm and the phase difference is 18 degrees.

[0044] In other embodiments, the phase difference and TM can also be adjusted by regulating the lengths of the first and third steps 21. 12 The actual energy percentage.

[0045] In some embodiments of the present invention, please refer to Figure 9 In TM 10 Introducing TM based on the pattern 12 The steps of the pattern also introduce x The first electric field component in the direction is introduced during the chamfering process at the edge of the inner peripheral wall of the angular radiation segment 30. x The second electric field component is oriented in the opposite direction to the first electric field component, in order to suppress cross-polarization. See also... Figure 9 When according to TE 10 Pattern and TM 12 While synthesizing the electric field in the mode can reduce the E-plane sidelobes, it inevitably introduces... x The electric field in the direction of the direction leads to cross-polarization ( Figure 9 The first figure in the text), from Figure 9The second figure shows that when we make an internal chamfer at the diagonal, we can introduce an electric field component in another direction, thereby canceling out the original electric field component and ultimately reducing cross-polarization. Figure 9 (The third figure in the text).

[0046] In some embodiments of the present invention, please refer to Figure 10 The angle and size of the chamfer are adjusted according to the magnitude of the first electric field component. The angle of the chamfer is the angle between its hypotenuse and the inner side of the radiating aperture. CX The chamfer dimension is the length of the hypotenuse at the radiating aperture. The larger the first electric field component, the larger the chamfer and its hypotenuse length should be. See also... Figure 10 Figure (a) shows the chamfer dimensions and chamfer angles. x The amplitude of the electric field component changes along the direction, and the optimal chamfer size varies for different angles. Considering symmetry, a chamfer angle of 45° is chosen. CX A chamfer size of 2.9mm can achieve good cross-polarization suppression. Please refer to [link / reference]. Figure 10 In (b), when the chamfer angle is 45° and CX When the cross-polarization is 2.9 mm, the corresponding cross-polarization also decreases significantly from -30 dB to below -40 dB.

[0047] Please also see Figure 11 , Figure 11 (a) gives CX Changes in the reflection coefficient under varying gain Figure 11 (b) gives CX The change in sidelobe level under varying conditions, from Figure 11 As can be seen, the introduction of the chamfer structure 31 also reduces the sidelobe level to some extent. In summary, by precisely controlling the amplitude and phase of higher-order modes and introducing different electric field components through the chamfer structure 31, we have achieved synergistic optimization of the sidelobes and cross-polarization of the Bode horn.

[0048] Please see Figures 2 to 4 The present invention also provides a rectangular horn antenna, which is optimized using the performance optimization method described in any of the above embodiments. The rectangular horn antenna includes a feed conversion section 10, a matching section 20, and an angular radiation section 30 connected in sequence. The end of the feed conversion section 10 away from the matching section 20 is a rectangular waveguide, and the other end of the feed conversion section 10 is a feed port. The matching section 20 has a multi-stage stepped structure, and the size of the matching section 20 gradually increases from the feed conversion section 10 to the angular radiation section 30. The multi-stage stepped structure is used to excite higher-order modes to reduce sidelobes. The radiation aperture of the angular radiation section 30 is rectangular, and the edges of the inner peripheral wall of the angular radiation section 30 have a chamfered structure 31, which is used to suppress cross-polarization.

[0049] The feed transition section 10 gradually transitions the rectangular waveguide to the feed port of the horn antenna. The feed transition section 10 primarily serves to smooth the structural transition, reduce port reflection, and extend the reflection coefficient bandwidth. The matching end of the multi-stage stepped structure can introduce higher-order modes and reduce sidelobe levels. The angular radiation section 30 ensures smooth transmission of electromagnetic waves into free space and reduces impedance discontinuities at the interface with free space. The inner periphery of the angular radiation section 30 has a chamfered structure 31 at its edges, which effectively suppresses cross-polarization.

[0050] The rectangular horn antenna provided by this invention employs the aforementioned performance optimization method, introducing higher-order modes TM by setting a multi-stage stepped matching segment 20. 12 By reducing the sidelobe level and suppressing cross-polarization by setting a chamfered structure 31 at the edge of the inner peripheral wall of the angular radiation section 30, the radiation characteristics are fundamentally optimized in a synergistic manner while maintaining its inherent advantages such as simple structure, convenient processing, and wide bandwidth operation to the maximum extent. In particular, it effectively suppresses the troublesome D-plane cross-polarization and reduces the sidelobe level, thereby meeting the extreme requirements of the next generation of high-performance communication systems for antenna polarization purity and pattern quality.

[0051] In some embodiments of the present invention, the resonant mode of the rectangular horn antenna is TM. 10 Pattern and TE 12 The composite mode of the mode, the higher-order mode is TE 12 Mode. Without matching segment 20, the original resonant mode at the radiating aperture is TM. 10 Adding a matching segment 20 to the multi-level stepped structure will introduce higher-order modes (TM). 12 ),TM 10 and TM 12 Superimposed, TM 12 The far-field pattern of the mode can perfectly fill the TE. 10 The first zero point of the mode results in a wider main lobe range and smaller side lobes (the original main lobe and the first side lobe merge, and the second side lobe becomes the new first side lobe). Based on the above analysis, we can know that appropriate excitation and a suitable proportion of TM... 12 The mode (ideal energy ratio) can reduce the sidelobe of the E-plane.

[0052] In some embodiments of the present invention, the multi-level stepped structure has three levels. 12 Under ideal energy ratio, the mode can greatly reduce the sidelobes of the E-plane. When the number of stages in the multi-stage stepped structure is 3, the actual energy ratio generated is closer to the ideal energy ratio than other stages, and the effect of reducing the sidelobe level is better.

[0053] In some embodiments of the present invention, the chamfered structure 31 has an angle of 45 degrees, and the length of the beveled surface of the chamfered structure 31 is 2.8 mm to 3 mm. To make the angular radiating segment 30 a symmetrical structure, the angle of the chamfered structure 31 can be set to 45 degrees. Combined with... Figure 10 When the chamfered structure 31 has an angle of 45 degrees and the chamfered surface length of 31 is 2.8 mm to 3 mm, a good cross-polarization suppression effect can be achieved.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for optimizing the performance of a rectangular horn antenna, characterized in that, Includes the following steps: A horn antenna is provided, comprising a feed conversion section and an angular radiating section connected in sequence. The end of the feed conversion section away from the angular radiating section is a rectangular waveguide, and the other end of the feed conversion section is a feed port. The radiating aperture of the angular radiating section is rectangular. A matching section is designed between the feed conversion section and the angular radiation section, and the matching section is designed as a multi-level stepped structure to achieve TM 10 Introducing TM based on the pattern 12 In this mode, the dimension of the multi-level stepped structure near the end of the feed conversion section is smaller than the dimension near the end of the angular radiation section; Determine TM 12 The ideal energy ratio of the mode is determined, and the number of stages of the multi-stage ladder structure is determined based on the ideal energy ratio to realize TM. 12 The actual energy percentage of the mode, while reducing the sidelobes of the E-plane; Adjusting the length of the third step alters the actual energy percentage, bringing it closer to the ideal energy percentage, while simultaneously changing TM. 12 Pattern and TM 10 Phase difference between modes to further reduce sidelobes on the E plane; The edges of the inner peripheral wall of the angular radiation segment are chamfered to suppress cross-polarization; Adjust the angle and size of the chamfer to further suppress cross-polarization.

2. The performance optimization method for a rectangular horn antenna as described in claim 1, characterized in that, The number of stages in the multi-stage ladder structure is determined based on the ideal energy ratio to achieve TM. 12 The actual energy percentage of the mode, while reducing the sidelobes of the E-plane, includes the following steps: TM 12 The mode, under the stated actual energy percentage, TM 12 Far-field pattern filling TE of the mode 10 The first null of the far-field pattern of the mode causes the first sidelobe of the E-plane to merge with the main lobe, thereby reducing the sidelobes of the E-plane.

3. The performance optimization method for a rectangular horn antenna as described in claim 2, characterized in that, The ideal energy percentage is 10% to 14%, the number of stages in the multi-level stepped structure is 3, and the actual energy percentage is 20% to 26%.

4. The performance optimization method for a rectangular horn antenna as described in claim 1, characterized in that, The length of the third step is 8 mm to 13.2 mm, and the phase difference is 16 to 20 degrees.

5. The performance optimization method for a rectangular horn antenna as described in claim 1, characterized in that, In TM 10 Introducing TM based on the pattern 12 The steps of the pattern also introduce x The first electric field component in the direction is introduced in the step of chamfering the edge of the inner peripheral wall of the angular radiation segment. x The second electric field component is in the direction of the first electric field component and the second electric field component, and the directions of the first electric field component and the second electric field component are opposite to those of the first electric field component, so as to suppress cross-polarization.

6. The performance optimization method for a rectangular horn antenna as described in claim 5, characterized in that, The angle and size of the chamfer are adjusted according to the magnitude of the first electric field component.

7. A rectangular horn antenna, using the performance optimization method for the rectangular horn antenna according to any one of claims 1-6, characterized in that: The device includes a feed conversion section, a matching section, and an angular radiation section connected in sequence. The end of the feed conversion section away from the matching section is a rectangular waveguide, and the other end of the feed conversion section is a feed port. The matching section has a multi-stage stepped structure, and the size of the matching section gradually increases from the feed conversion section to the angular radiation section. The multi-stage stepped structure is used to excite higher-order modes to reduce sidelobes. The radiation aperture of the angular radiation section is rectangular, and the edges of the inner peripheral wall of the angular radiation section have a chamfered structure, which is used to suppress cross-polarization.

8. The rectangular horn antenna as described in claim 7, characterized in that: The resonant mode of the rectangular horn antenna is TM. 10 Pattern and TE 12 The composite mode of the mode, wherein the higher-order mode is TE 12 model.

9. The rectangular horn antenna as described in claim 7, characterized in that: The multi-level stepped structure has 3 levels.

10. The rectangular horn antenna as described in claim 7, characterized in that: The chamfered structure has an angle of 45 degrees, and the length of the chamfered surface is 2.8 mm to 3 mm.

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