A satellite-borne antenna based on structural spline function directivity pattern shaping

Abstract

The application relates to the technical field of antennas, and particularly discloses a satellite-borne antenna based on a structural spline function directional diagram shaping, which comprises a feed waveguide, a transition device, a conversion section and a choke structure; the feed waveguide, the transition device, the conversion section and the choke structure are sequentially connected in series; the inside of the conversion section is provided with a gourd-shaped cavity, the large end of the cavity is arranged on the side close to the choke structure, and the small end of the cavity is arranged on the side close to the feed waveguide. The discontinuity of the waveguide is changed by shaping the inner wall of the antenna through the structural spline function, so that the control of the high-order mode excitation ratio is realized, then the mode field of the radiation surface is disturbed in amplitude and phase through the choke phase distribution groove, and finally the shaped directional diagram with specific requirements is obtained. The application can solve the problems of the existing satellite-borne antenna, such as miniaturization difficulty, low power capacity, poor shaping beam equalization, small shaping angle and the like.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and more specifically, to a spaceborne antenna based on structured spline function pattern shaping. Background Technology

[0002] In the use of spaceborne platforms, the special illumination requirements for ground targets often necessitate antenna pattern shaping design to achieve the target coverage requirements.

[0003] In existing designs, antenna pattern shaping can be achieved using a single antenna or an array antenna. Array antennas utilize the classic principles of planar or three-dimensional antenna arrays, configuring the amplitude and phase of each element to achieve antenna pattern shaping. Their characteristics include a large physical aperture, low antenna array efficiency, and the need for active or passive beamforming networks. All of these factors lead to a significant increase in the overall weight of the antenna, making it difficult to meet the current lightweight requirements of satellite payloads.

[0004] Traditional single-antenna beamforming design utilizes the amplitude and phase superposition characteristics of the antenna aperture field to form a beamforming pattern that meets the requirements. Its characteristics include a large influence of the aperture field on the antenna's inherent form, poor beamforming equalization, and low power capacity. Currently, existing technologies cannot meet the requirements of spaceborne platforms for antenna miniaturization, high power capacity, and large-angle beamforming. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a spaceborne antenna based on structured spline function pattern shaping. By shaping the inner wall of the antenna using a structured spline function to change the discontinuities of the waveguide, the excitation ratio of higher-order modes can be controlled. Furthermore, amplitude and phase perturbations of the mode field at the radiating aperture are performed through a choke phase slot, ultimately obtaining a shaped radiation pattern with specific requirements. This invention can solve the problems faced by existing spaceborne antennas, such as miniaturization difficulties, low power capacity, poor beam equalization, and small shaping angle.

[0006] The solution adopted by this invention to solve the technical problem is:

[0007] A spaceborne antenna based on structured spline function pattern shaping, including a transmission mode of TE 10 The mode-fed waveguide is used to transmit TE signals. 10 Mode conversion to TE 11 Mode transitioner, used to transition TE 11 The pattern stimulates the transition segment of higher-order modes and the choke structure;

[0008] The feed waveguide, transition device, switching section, and choke structure are cascaded in sequence.

[0009] The conversion section has a gourd-shaped cavity inside, with the larger end of the cavity located near the choke structure and the smaller end located near the feed waveguide.

[0010] In some possible implementations,

[0011] The cross-section of the inner wall of the cavity is a structural curve and is a cubic spline function based on electrical characteristics; the length of the cavity is 1mc, the size of the radiation aperture is rmc, and the number of interpolation points is Nmc.

[0012] Where 0.9λ0≤lmc≤2.5λ0, λ0 is the working wavelength corresponding to the working center frequency;

[0013] 1.05rwc≤rmc≤2.03rwc;

[0014] 4≤Nmc≤8.

[0015] In some possible implementations,

[0016] Multiple sets of annular choke phase matching grooves are provided on the side of the choke structure away from the conversion section, and the multiple sets of choke phase matching grooves are coaxially arranged.

[0017] In some possible implementations,

[0018] The number of choke phase-matching grooves is Ncp, the depth of the groove is dcp, and the width of the groove is wcp; wherein, 5≤Ncp≤9, 0.62λ0≤dcp≤0.9λ0, and 0.15λ0≤wcp≤0.4λ0.

[0019] In some possible implementations,

[0020] Each group of choke phase-matching grooves is annular.

[0021] In some possible implementations,

[0022] The feeding waveguide is a rectangular feeding waveguide with a wide side dimension of a and a narrow side dimension of b, where a = (0.72 ± 0.15)λ0 and b = (0.35 ± 0.1)λ0.

[0023] In some possible implementations,

[0024] The transition is a rectangular-circular transition, wherein the circular diameter is Rwc, the length of the rectangular-circular transition is Lwc, 0.82a≤Rwc≤1.03a, and 0.42λ0≤Lwc≤0.48λ0.

[0025] In some possible implementations,

[0026] The feed waveguide, transition, switching section, and choke structure are made of metallic materials.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] This invention effectively realizes the conversion of the radiating aperture surface field and mode generation; by using a choke phase slot design to perturb the amplitude and phase of the radiating aperture surface field, the antenna performance with characteristics such as simple structure, miniaturization, equal radiation pattern, and good standing wave performance is finally obtained.

[0029] The switching section of this invention alters the discontinuity of the waveguide, thereby controlling the excitation ratio of higher-order modes and ensuring the transmission and stable mode ratio of composite modes. It avoids structural instability caused by the Runge phenomenon and also possesses a "convexity preservation" characteristic, giving the antenna structure good manufacturability. The superposition of fundamental and higher-order modes with different ratios forms a relatively uniform amplitude aperture field, ensuring beam equalization requirements.

[0030] The antenna choke phase slot provided by this invention can not only effectively disturb the amplitude and phase of the radiation aperture field, but also suppress the influence of carrier creeping waves and circling waves on the antenna shaping pattern.

[0031] This invention employs an all-metal structure design, and the antenna withstands a very high breakdown electric field in a vacuum, which ensures that the antenna has the maximum power tolerance characteristics. Attached Figure Description

[0032] Figure 1 Schematic diagram of the present invention;

[0033] Figure 2 Cross-sectional schematic diagram of this invention;

[0034] Figure 3 Schematic diagram of structural dimensions in this invention;

[0035] Figure 4 A schematic diagram of the sampling points and interpolation curves of the cubic ratio spline function of the inner wall of the cavity in this invention;

[0036] Figure 5 Schematic diagram of the feed-in waveguide structure of this invention;

[0037] Figure 6 A schematic diagram of the transition device in this invention;

[0038] Figure 7 A schematic diagram of the voltage standing wave ratio curve of this invention;

[0039] Figure 8 The present invention provides a low-frequency shaped radiation pattern.

[0040] Figure 9 The frequency center shaping pattern of this invention;

[0041] Figure 10 The present invention provides a high-frequency high-end shaping pattern;

[0042] Among them, 1. Feed waveguide; 2. Transition device; 3. Switching section; 31. Chamber; 4. Choke structure; 41. Choke phase slot. Detailed Implementation

[0043] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. The terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, "a" or "one," etc., do not indicate a quantity limitation, but rather indicate the existence of at least one. In the implementation of this application, "and / or" describes the association relationship of related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more. For example, multiple positioning posts refer to two or more positioning posts. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0044] The present invention will now be described in detail.

[0045] like Figures 1-6 As shown, a spaceborne antenna based on structured spline function pattern shaping includes a transmission mode of TE. 10 Mode feed waveguide 1, used to feed TE 10 Mode conversion to TE 11 Mode transitioner 2, used to transition TE 11 The mode excites the transition segment 3 of the higher-order mode and the choke structure 4;

[0046] The feed waveguide 1, transition 2, switching section 3, and choke structure 4 are cascaded in sequence.

[0047] The conversion section 3 has a gourd-shaped chamber 31 inside. The large end of the chamber 31 is located on the side near the choke structure 4, and the small end of the chamber 31 is located on the side near the feed waveguide 1.

[0048] In some possible implementations,

[0049] The cross-section of the inner wall of the chamber 31 is a structural curve and is a cubic spline function based on electrical characteristics; the length of the chamber 31 is 1mc, the size of the radiating aperture is rmc, and the number of interpolation points is Nmc.

[0050] Where 0.9λ0≤lmc≤2.5λ0, λ0 is the working wavelength corresponding to the working center frequency;

[0051] 1.05rwc≤rmc≤2.03rwc;

[0052] 4≤Nmc≤8.

[0053] In some possible implementations,

[0054] Multiple sets of annular choke phase matching grooves 41 are provided on the side of the choke structure 4 away from the conversion section 3. Through holes coaxial with and interconnected with the chamber 31 are provided on the choke structure 4. The multiple sets of choke phase matching grooves 41 are coaxially arranged.

[0055] In some possible implementations,

[0056] The number of choke phase-matching grooves 41 is Ncp, the depth of the groove is dcp, and the width of the groove is wcp; wherein, 5≤Ncp≤9, 0.62λ0≤dcp≤0.9λ0, and 0.15λ0≤wcp≤0.4λ0.

[0057] In some possible implementations,

[0058] Each group of choke phase-matching grooves 41 is annular.

[0059] In some possible implementations,

[0060] The feeding waveguide 1 is a rectangular feeding waveguide 1, with the wide side dimension being a and the narrow side dimension being b, where a = (0.72 ± 0.15)λ0 and b = (0.35 ± 0.1)λ0.

[0061] In some possible implementations,

[0062] The transition device 2 is a rectangular-circular transition device 2, wherein the circular diameter is Rwc, the length of the rectangular-circular transition device 2 is Lwc, 0.82a≤Rwc≤1.03a, and 0.42λ0≤Lwc≤0.48λ0.

[0063] In some possible implementations,

[0064] The feed waveguide 1, transition device 2, switching section 3, and choke structure 4 are made of metallic materials.

[0065] Example 1:

[0066] A spaceborne antenna based on structured spline function pattern shaping includes a cascaded rectangular feed waveguide 1, a rectangular-circular transition 2, a transition section 3, and a choke structure 4 with multiple sets of choke phase slots 41. Each set of choke phase slots 41 is annular, and the multiple sets of choke slots are coaxially arranged.

[0067] The rectangular feed waveguide 1, rectangular-circular transition 2, switching section 3, and choke structure 4 involved are all made of metal. Through reasonable structural design, the antenna not only has excellent mechanical performance, but also, due to the use of metal materials, the antenna can withstand a high breakdown electric field in a vacuum, ensuring that the antenna has the maximum power handling characteristics. The antenna has a simple and reliable structure, small size, light weight, good structural mechanical properties, low transmission loss, and can withstand high power.

[0068] Feed waveguide 1 is a rectangular feed waveguide 1 as used in the prior art, used to provide power to the antenna, and the transmission mode is the rectangular waveguide fundamental mode TE10 mode; such as Figure 5 As shown, the rectangular feed waveguide 1 has a rectangular aperture with a wide side dimension and a rectangular aperture with a narrow side dimension, where a = (0.72 ± 0.15)λ0 and b = (0.35 ± 0.1)λ0, where λ0 is the operating wavelength corresponding to the operating center frequency. The rectangular feed waveguide 1 mainly provides TE10 mode feed input for the antenna and has a standard flange mounting interface.

[0069] Transition 2 is the existing rectangular-to-circular transition 2, whose main function is to convert the TE10 mode transmitted through the rectangular-fed waveguide 1 into the TE11 mode transmitted through the circular waveguide; such as Figure 3 As shown, the circular diameter of the rectangular-circular transition 2 is Rwc, and the length of the rectangular-circular transition 2 is Lwc, where 0.82a≤Rwc≤1.03a and 0.42λ0≤Lwc≤0.48λ0.

[0070] The main function of the transition section 3 is to excite different higher-order modes such as TH01, TE21, and TE01 through microwave structure based on the TE11 mode transmitted by the circular waveguide. The cross-section of the inner wall of the transition section 3 is a structural curve, which is an electric cubic spline function (ECS) based on electrical characteristics. Its advantage is that it ensures the transmission of composite modes and the stable mode ratio in terms of electrical aspects.

[0071] The inner wall of the transition section 3 is designed using an electrically optimized spline function (ECS) to form a gourd-shaped cavity 31. The larger end of cavity 31 is positioned near the choke structure 4, while the smaller end is near the feed waveguide 1. This excites a composite mode of multiple higher-order modes. Through mode conversion and mode matching, a specific amplitude and phase distribution of the radiating aperture field is formed. The amplitude and phase of the radiating aperture field are then perturbed by the choke phase matching slot 41, ultimately forming a shaped radiation pattern that meets the requirements. This structure of the transition section 3 avoids structural instability caused by the Runge phenomenon and also possesses "convexity preservation" characteristics, giving the antenna structure good manufacturability. The superposition of fundamental and higher-order modes with different ratios forms a relatively uniform amplitude aperture field, ensuring beam equalization requirements. Figure 4 The figure shows the shaping curve of the inner wall of the transformation segment 3, with 6 sampling points and ECS interpolation method. Through the internal shaping design, the TE11 mode is effectively transmitted and can stimulate the required higher-order mode.

[0072] like Figure 3 As shown, the length of the conversion segment 3 is lmc, the size of the radiation aperture is rmc, and the number of ECS interpolation points is Nmc, where 0.9λ0≤lmc≤2.5λ0, 1.05rwc≤rmc≤2.03rwc, and 4≤Nmc≤8.

[0073] The choke phase slot 41 set on the choke structure 4 has the main function of perturbing the amplitude and phase of the composite mode field of the radiation aperture. The perturbation will cause the amplitude and phase of the aperture field to change. The specific amplitude and phase perturbation results in a specific beamforming pattern.

[0074] like Figure 3 As shown, the number of choke phase-matching grooves 41 is Ncp, the depth of the groove is dcp, and the width of the groove is wcp, where 5≤Ncp≤9, 0.62λ0≤dcp≤0.9λ0, and 0.15λ0≤wcp≤0.4λ0.

[0075] The present invention provides a pattern-shaped antenna, which has the advantages of low reflection coefficient, wide-angle pattern shaping greater than 140°, and beam equalization;

[0076] The number of ECS interpolation points Ncp and the length lmc of the conversion segment 3 provided by this invention determine the number of modes and the mode ratio of the antenna. By rationally designing these two parameters, the antenna can ensure beam equalization performance while minimizing its length and reducing the antenna profile height.

[0077] The antenna choke phasing slot 41 provided by this invention not only effectively perturbs the amplitude and phase of the radiating aperture field, but also suppresses the influence of carrier creeping waves and circling waves on the antenna pattern. Theoretically, the more choke phasing slots 41 there are, the stronger their ability to perturb the amplitude and phase of the radiating aperture. However, when the number of choke phasing slots 41 exceeds 10, their perturbation capability weakens, resulting in a significant increase in antenna size and weight, while the perturbation effect remains limited. The structural curve of the transition section 3 is composed of a cubic spline structure; the choke phasing slot 41 consists of 7 slots, each with a depth between 0.62λ0 and 0.9λ0 and a width between 0.15λ0 and 0.4λ0.

[0078] Figure 7 The voltage standing wave ratio (VSWR) of the antenna is less than 1.25 within the operating frequency band, indicating that the antenna has a low reflection coefficient.

[0079] Figures 8-10 The antenna's radiation pattern is shaped; the results show that the antenna exhibits good beam equalization in the φ=0°, 45°, and 90° sections; and the antenna gain is greater than -1dB within a maximum coverage area of ​​140° (±70°).

[0080] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A spaceborne antenna based on structured spline function pattern shaping, characterized in that, This includes the feed waveguide, transition, switching section, and choke structure; The feed waveguide, transition device, switching section, and choke structure are cascaded in sequence. The conversion section has a gourd-shaped cavity inside, with the large end of the cavity located near the choke structure and the small end of the cavity located near the feed waveguide. The cross-section of the inner wall of the cavity is a structural curve and is a cubic spline function based on electrical characteristics; the length of the cavity is lmc, the size of the radiation aperture is rmc, and the number of interpolation points is Nmc; where 0.9λ0≤lmc≤2.5λ0, λ0 is the working wavelength corresponding to the working center frequency; 1.05rwc≤rmc≤2.03rwc; 4≤Nmc≤8; The transmission mode of the feed waveguide is TE. 10 model; The transition is used to transfer TE 10 Mode conversion to TE 11 Pattern transitioner; The conversion segment is used to convert TE 11 The pattern inspires higher-order patterns.

2. The spaceborne antenna based on structured spline function pattern shaping according to claim 1, characterized in that, Multiple sets of annular choke phase matching grooves are provided on the side of the choke structure away from the conversion section, and the multiple sets of choke phase matching grooves are coaxially arranged.

3. A spaceborne antenna based on structural spline function pattern shaping according to claim 2, characterized in that, The number of choke phase-matching grooves is Ncp, the depth of the groove is dcp, and the width of the groove is wcp; wherein, 5≤Ncp≤9, 0.62λ0≤dcp≤0.9λ0, and 0.15λ0≤wcp≤0.4λ0.

4. A spaceborne antenna based on structural spline function pattern shaping according to claim 2, characterized in that, Each group of choke phase-matching grooves is annular.

5. A spaceborne antenna based on structural spline function pattern shaping according to claim 1, characterized in that, The feeding waveguide is a rectangular feeding waveguide with a wide side dimension of a and a narrow side dimension of b, where a = (0.72 ± 0.15)λ0 and b = (0.35 ± 0.1)λ0.

6. A spaceborne antenna based on structural spline function pattern shaping according to claim 1, characterized in that, The transition is a rectangular-circular transition, wherein the circular diameter is Rwc, the length of the rectangular-circular transition is Lwc, 0.82a≤Rwc≤1.03a, and 0.42λ0≤Lwc≤0.48λ0.

7. A spaceborne antenna based on structured spline function pattern shaping according to any one of claims 1-6, characterized in that, The feed waveguide, transition, switching section, and choke structure are made of metallic materials.

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