Dual-polarized corrugated feed source offset-feed small-sized parabolic reflecting antenna and design method thereof

Abstract

The invention discloses a dual-polarized corrugated feed source offset-feed small parabolic reflection antenna and a design method thereof, the dual-polarized corrugated feed source comprises a dual-polarized corrugated feed source, a connection support and a reflection surface, the dual-polarized corrugated feed source is designed according to a sequential structure of a feed section, a transition section, a field transformation section and a radiation section, and the transition section and the field transformation section adopt gradual change corrugated groove depth design. The radiation section adopts a center frequency wavelength quarter depth design; and the connecting bracket is used for fixing the dual-polarized corrugated feed source and the reflecting surface, so that the requirement of the dual-polarized corrugated feed source on offset feed of the reflecting surface is met. The design method comprises the following steps: designing and simulating the dual-polarized corrugated feed source to adapt to the small parabolic reflection antenna, realizing vertical and horizontal polarization, and enabling the index of the parabolic reflection antenna to meet the use index requirement. According to the invention, microwave signals are received and transmitted to the space through the small-sized reflecting surface, so that the signals are received and transmitted, the rear end of a radar system can process the signals conveniently, the size is small, and the gain is appropriate.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic countermeasure and radar, and in particular to a dual-polarization corrugated feed offset-fed small parabolic reflector antenna and a design method thereof. Background Art

[0002] Antennas are important detection parts in the field of radar technology and electronic countermeasures. With the rapid development of electronic technology, various electronic equipment emerges in an endless stream, and various types of antennas and polarization forms that can adapt to different environments are needed. In radar technology, reflector antennas have simple structures, are durable, and are not easy to damage. They also have good electrical properties. Therefore, reflector antennas with moderate performance and economy still occupy a certain position. As an important component of the reflector antenna, the feed source radiates the RF power from the feed line to the reflector in the form of electromagnetic waves, so that it produces a suitable field distribution on the aperture to form the required sharp beam or shaped beam; at the same time, the power leaking out of the edge of the reflector is minimized in order to achieve the highest possible gain.

[0003] Feed design is a key part of reflector antenna design. Usually the corrugated horn is an ideal feed horn, and its corrugated structure design can produce mixed mode HE 11 , in HE 11 The TE and TM components in the mode have the same cutoff frequency and phase velocity. Therefore, the E-plane and H-plane directivity diagrams have good equalization within a certain working bandwidth, the phase center is basically independent of the frequency, and has good cross-polarization performance and sidelobe characteristics. The ring-loaded corrugated horn further widens the frequency band. The corrugated horn is used as a planar antenna feed source to reduce overflow loss, improve irradiation efficiency, and increase polarization purity. It can be widely used in various linear polarization and circular polarization planar antennas. Summary of the invention

[0004] The purpose of the present invention is to provide a dual-polarized corrugated feed offset-fed small parabolic reflector antenna and a design method thereof. The designed dual-polarized corrugated feed adopts a corrugated groove design so that the electromagnetic field distribution meets the illumination requirements of the small parabolic reflector antenna. At the same time, the offset feed design is adopted so that the radiation pattern beam width and side lobe and other indicators of the small parabolic reflector antenna meet the use requirements.

[0005] The technical solution to achieve the purpose of the present invention is: a dual-polarized corrugated feed offset-fed small parabolic reflector antenna, comprising a dual-polarized corrugated feed, a connecting bracket, and a reflector, wherein:

[0006] The dual-polarization corrugated feed adopts a four-section structure design, which is designed in the order of a feeding section, a transition section, a field conversion section and a radiation section. The transition section and the field conversion section adopt a gradient corrugated groove depth design, and the radiation section adopts a quarter-center frequency wavelength depth design.

[0007] The connecting bracket is used to fix the dual-polarization corrugated feed source and the reflecting surface, so as to realize the requirement of the dual-polarization corrugated feed source for offset feeding of the reflecting surface.

[0008] Furthermore, the connecting bracket includes a base, and a first bracket, a second bracket, and a third bracket sequentially arranged on the upper surface of the base;

[0009] The first bracket fixes the transition section of the dual-polarization corrugated feed source, and the second bracket fixes the radiation section of the dual-polarization corrugated feed source;

[0010] The third bracket is used to fix the reflecting surface.

[0011] Furthermore, the first bracket and the second bracket can adjust the inclination angle of the dual-polarization corrugated feed, that is, adjust the offset feeding angle of the dual-polarization corrugated feed to the reflecting surface.

[0012] Furthermore, the third bracket can move relative to the second bracket along the base to adjust the distance between the reflecting surface and the dual-polarization corrugation feed, and fine-tune the focal length of the dual-polarization corrugation feed relative to the reflecting surface, so that the dual-polarization corrugation feed is located at the focal length position of the reflecting surface.

[0013] Furthermore, the gradual corrugation grooves of the transition section and the field conversion section in the dual-polarization corrugation feed are formed by electroforming and then machining.

[0014] Furthermore, the feeding section of the dual-polarization corrugated feed source is fed by inserting mutually perpendicular metal probes into the circular waveguide, thereby realizing dual polarization.

[0015] Furthermore, the dual-polarization corrugated feed adopts a length transition of 3 times the center frequency wavelength to achieve HE 11 Mode conversion.

[0016] Furthermore, the depth of the corrugation groove of the dual-polarization corrugation feed is determined by a method of changing the depth as the inclination angle changes.

[0017] A design method for a dual-polarized corrugated feed offset-fed small parabolic reflector antenna comprises the following steps:

[0018] Step 1: According to the lower limit of the design frequency, according to the excitation HE 11 The mode determines the radius of the circular waveguide, i.e. a ≥ C / (3.41)f L , where a is the radius of the circular waveguide, C is the speed of light, and f L is the lower limit of the design frequency, from which the diameter of the feed section is obtained;

[0019] Step 2: Consider the excitation HE in the circular waveguide according to the upper and lower limits of the design center frequency. 11 The mode is used to determine the diameter and length of the circular waveguide transitioning to the first corrugated groove. The formula is as follows:

[0020] a(z)=a i +(a1-a i )sin(πz / (2z t ))

[0021] Where a(z) is the waveguide diameter corresponding to the change in z, starting from 0 to z t , that is, the diameter of the circular waveguide is changing; z t is the length of the transition section, the shortest being one waveguide wavelength; a i is the initial circular waveguide radius; a1 is determined by K i a1=2.7~3.4, the wave number K of the ith frequency point i =2π / λ i ;

[0022] Step 3: Considering cross polarization and mode conversion, design the field conversion section and radiation section of the corrugated slot. The design formula of the corrugated slot is determined by the following formula:

[0023] a L+1 is the radius at the end of the field transformation segment, K i a L+1 >3.5;P i / λ i Indicates the slot spacing, P i / λ i <0.175; W i / P i Indicates the ratio of slot width to slot spacing, W i / P i ≥0.75;θ i Indicates the half angle of the field change segment, θ i =4°~8°;

[0024] d i =exp(1 / (2.5K i a i )) / 4

[0025] Where d i represents the depth of the i-th slot;

[0026] Step 4: Consider cross-polarization and high-frequency high-order mode suppression and design the radiation section;

[0027] The opening angle of the radiation section is the same as that of the field conversion section, the slot width and slot spacing remain unchanged, only the slot depth is changed, and the length of 3 times the center frequency wavelength is selected to meet the radiation pattern design requirements;

[0028] Step 5. According to the design dimensions, use HFSS simulation software to simulate and verify the designed dual-polarization corrugated feed dimensions. After optimizing the groove depth, field conversion segment half angle and the number of corrugated grooves, the optimal dual-polarization corrugated feed dimensions are obtained. Use CST simulation software to jointly simulate and verify the dual-polarization corrugated feed and the reflecting surface. After adjusting the focal length, the optimal result is obtained. According to the optimal result, the structural drawings are designed and processed.

[0029] Furthermore, the design method of the dual-polarization corrugated feed offset-fed small parabolic reflector antenna also includes the following test verification steps:

[0030] The dual-polarization corrugated feed and the reflector are fixed to the connecting bracket by using mutually perpendicular metal probes for excitation, and the electrical performance of the dual-polarization corrugated feed is debugged and tested.

[0031] Compared with the prior art, the present invention has the following significant advantages:

[0032] (1) The dual-polarization corrugated feed is designed and simulated to adapt to the small parabolic reflector antenna, and both vertical and horizontal polarizations are realized at the same time, so that the indicators of the parabolic reflector antenna meet the indicator requirements for use;

[0033] (2) The designed dual-polarized corrugated feed source mainly adopts the corrugated groove design. By setting certain parameters such as transition section, corrugated groove, tilt angle, etc., its electromagnetic field distribution meets the illumination requirements of the small parabolic reflector antenna. At the same time, the small parabolic reflector antenna adopts the offset feed design, so that the radiation pattern beam width and side lobe of the small parabolic reflector antenna meet the use requirements.

[0034] (3) It is used for receiving and transmitting signals in radar systems. It receives and transmits vertically and horizontally polarized microwave signals. It receives and transmits microwave signals into space through a small reflector, thereby completing signal reception and transmission. It is convenient for the back-end of the radar system to process. It has a small size and appropriate gain. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural diagram of the dual-polarization corrugated feed offset-fed small parabolic reflector antenna of the present invention.

[0036] Figure 2 It is a schematic diagram of the structure of a dual-polarized corrugated feed in a dual-polarized corrugated feed offset-fed small parabolic reflector antenna.

[0037] Figure 3 It is a schematic diagram of the structure of the connecting bracket in the dual-polarization corrugated feed offset-fed small parabolic reflector antenna.

[0038] Figure 4 This is a simulated illumination pattern of the dual-polarization corrugated feed of the present invention.

[0039] Figure 5 It is a schematic diagram of the simulation structure of the dual-polarization feed offset-fed small parabolic reflector antenna of the present invention.

[0040] Figure 6 The simulated radiation pattern of the dual-polarization feed offset-fed small parabolic reflector antenna of the present invention.

[0041] Figure 7 Three views of the actual processing structure of the dual-polarization corrugated feed of the present invention.

[0042] Figure 8 The three-view diagram of the feed bracket structure of the dual-polarization feed offset-fed small parabolic reflector antenna of the present invention.

[0043] Fig. 9 The three-view diagram of the dual-polarization feed offset-fed small parabolic reflector antenna structure of the present invention.

[0044] Fig.10 This is the actual radiation pattern of the dual-polarization feed offset-fed small parabolic reflector antenna after testing. DETAILED DESCRIPTION

[0045] The present invention is to meet the design requirements of a certain system, and designs a small parabolic reflector antenna, and designs a dual-polarized corrugated feed source that matches it. The dual-polarized corrugated feed source is designed and simulated to adapt to the small parabolic reflector antenna, and both vertical and horizontal polarizations are realized at the same time, so that the indicators of the parabolic reflector antenna meet the indicator requirements for use. The dual-polarized corrugated feed source designed by the invention mainly adopts a corrugated groove design, and its electromagnetic field distribution meets the illumination requirements of the small parabolic reflector antenna by setting certain parameters such as transition section, corrugated groove, and inclination angle. At the same time, the small parabolic reflector antenna adopts an offset feed design, so that the indicators such as the beam width and side lobe of the directional pattern of the small parabolic reflector antenna meet the use requirements.

[0046] The present invention discloses a dual-polarized corrugated feed offset-fed small parabolic reflector antenna, which is characterized by comprising a dual-polarized corrugated feed 1, a connecting bracket 2, and a reflecting surface 3, wherein:

[0047] The dual-polarization corrugated feed source 1 adopts a four-section structure design, and is designed in the order of a feeding section 1-1, a transition section 1-2, a field conversion section 1-3, and a radiation section 1-4. The transition section 1-2 and the field conversion section 1-3 adopt a gradual corrugation groove depth design, and the radiation section 1-4 adopts a center frequency wavelength quarter depth design;

[0048] The connecting bracket 2 is used to fix the dual-polarization corrugated feed source 1 and the reflecting surface 3 to achieve the requirement of bias feeding of the dual-polarization corrugated feed source 1 to the reflecting surface 3 .

[0049] As a specific example, the connecting bracket 2 includes a base 2-4, and a first bracket 2-1, a second bracket 2-2, and a third bracket 2-3 sequentially arranged on the upper surface of the base;

[0050] The first bracket 2-1 fixes the transition section 1-2 of the dual-polarization corrugated feed source 1, and the second bracket 2-2 fixes the radiation section 1-4 of the dual-polarization corrugated feed source 1;

[0051] The third bracket 2 - 3 is used to fix the reflecting surface 3 .

[0052] As a specific example, the first bracket 2-1 and the second bracket 2-2 can adjust the inclination angle of the dual-polarization corrugated feed source 1, that is, adjust the offset feeding angle of the dual-polarization corrugated feed source 1 to the reflecting surface 3;

[0053] As a specific example, the third bracket 2-3 can move along the base relative to the second bracket 2-2, adjust the distance between the reflecting surface 3 and the dual-polarization corrugated feed 1, and fine-tune the focal length of the dual-polarization corrugated feed 1 relative to the reflecting surface 3, so that the dual-polarization corrugated feed 1 is located at the focal length position of the reflecting surface 3, thereby making the reflecting surface antenna have a lower side lobe level and a relatively high gain.

[0054] As a specific example, the gradient corrugated grooves of the transition section 1-2 and the field transformation section 1-3 in the dual-polarization corrugated feed 1 are formed by electroforming and then machining.

[0055] As a specific example, the feeding section 1 - 1 of the dual-polarization corrugated feed 1 is fed by inserting mutually perpendicular metal probes into a circular waveguide, thereby achieving dual polarization.

[0056] As a specific example, the dual-polarization corrugated feed 1 uses a length transition of 3 times the center frequency wavelength to achieve HE 11 Mode conversion.

[0057] As a specific example, the depth of the corrugation groove of the dual-polarization corrugation feed 1 is determined by changing the depth as the inclination angle changes.

[0058] The present invention also provides a design method for a dual-polarization corrugated feed offset-fed small parabolic reflector antenna, comprising the following steps:

[0059] Step 1: According to the lower limit of the design frequency, according to the excitation HE 11 The mode determines the radius of the circular waveguide, i.e. a ≥ C / 3.41f L , where a is the radius of the circular waveguide, C is the speed of light, and f L is the lower limit of the design frequency, from which the diameter size of the feed section 1-1 is obtained;

[0060] Step 2: Consider the excitation HE in the circular waveguide according to the upper and lower limits of the design center frequency.11 The mode is used to determine the diameter and length of the circular waveguide transitioning to the first corrugated groove. The formula is as follows:

[0061] a(z)=a i +(a1-a i )sin(πz / (2z t ))

[0062] Where az is the waveguide diameter corresponding to the change of z, which starts from 0 and changes to z t , that is, the diameter of the circular waveguide is changing; z t is the length of transition section 1-2, the shortest of which is one waveguide wavelength; a i is the initial circular waveguide radius; a1 is determined by K i a1=2.7~3.4, the wave number K of the ith frequency point i =2π / λ i ;

[0063] Step 3: Considering cross polarization and mode conversion, the field conversion section 1-3 and radiation section 1-4 of the corrugated slot are designed. The design formula of the corrugated slot is determined by the following formula:

[0064] a L+1 K is the radius at the end of field transformation segment 1-3. i a L+1 >3.5;P i / λ i Indicates the slot spacing, P i / λ i <0.175; W i / P i Indicates the ratio of slot width to slot spacing, W i / P i ≥0.75;θ i Indicates the half angle of field change segment 1-3, θ i =4°~8°;

[0065] d i =exp(1 / (2.5K i a i )) / 4

[0066] Where d i represents the depth of the i-th slot;

[0067] Step 4: Considering cross polarization and high-frequency high-order mode suppression, design radiation segments 1-4;

[0068] The opening angle of the radiation section 1-4 is the same as that of the field conversion section 1-3, the slot width and slot spacing remain unchanged, only the slot depth is changed, and the length of 3 times the center frequency wavelength is selected to meet the radiation pattern design requirements;

[0069] Step 5. According to the design dimensions, use HFSS simulation software to simulate and verify the dimensions of the designed dual-polarization corrugated feed 1. After optimizing the groove depth, the half angle of the field conversion segment 1-3 and the number of corrugated grooves, the dimensions of the optimal dual-polarization corrugated feed 1 are obtained. Use CST simulation software to jointly simulate and verify the dual-polarization corrugated feed 1 and the reflecting surface 3. After adjusting the focal length, the optimal result is obtained. According to the optimal result, the structural drawings are designed and processed.

[0070] As a specific example, the design method of the dual-polarized corrugated feed offset-fed small parabolic reflector antenna also includes the following test verification steps:

[0071] By using mutually perpendicular metal probe excitation, the dual-polarization corrugated feed source 1 and the reflecting surface 3 are fixed to the connecting bracket 2, and the electrical performance of the dual-polarization corrugated feed source 1 is debugged and tested.

[0072] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0073] Example

[0074] Combination Figure 1 to Figure 3 This embodiment provides a design method for a dual-polarized feed offset-fed small parabolic reflector antenna, which includes a reflector 3, a connecting bracket 2, a dual-polarized corrugated feed 1, etc. The dual-polarized corrugated feed 1 mainly includes a feed section 1-1, a transition section 1-2, a field conversion section 1-3, and a radiation section 1-4. In actual processing, a two-segment structure design is adopted, and the field conversion section 1-3 and the radiation section 1-4 are combined into one section by electroforming and then processed.

[0075] The design method of the dual-polarization feed offset-fed small parabolic reflector antenna in this embodiment has the following specific steps:

[0076] Step 1: According to the lower limit of the design frequency, according to the excitation HE 11 The mode determines the radius of the circular waveguide, i.e. a ≥ C / (3.41)f L , where a is the radius of the circular waveguide, C is the speed of light, and f is L is the lower limit of the design frequency, from which the diameter size of the feeding section 1-1 is obtained.

[0077] Step 2: Consider the excitation HE in the circular waveguide according to the upper and lower limits of the design center frequency. 11 The mode determines the diameter and length of the circular waveguide transition to the first corrugated groove section.

[0078] a(z)=a i +(a1- a i )sin(πz / (2z t )) (1)

[0079] Where az is the waveguide diameter corresponding to the change of z, starting from 0 to z t , that is, the diameter of the circular waveguide is changing; z t is the length of transition section 1-2, the shortest of which is one waveguide wavelength; a i is the initial circular waveguide radius; a1 is determined by K i a1=2.7~3.4, the wave number K of the ith frequency point i =2π / λ i .

[0080] Step 3: Considering cross polarization and mode conversion, design the field conversion section 1-3 and radiation section 1-4 of the corrugated groove, which mainly involves parameters such as corrugated groove depth, number of grooves, and groove width. Usually, the design formula of the corrugated groove is determined by the following formula:

[0081] K i a L+1 >3.5 a L+1 The radius at the end of field transformation segment 1-3

[0082] P i / λ i <0.175 P i / λ i Indicates the slot spacing

[0083] W i / P i ≥0.75 W i / P i Indicates the ratio of slot width to slot spacing

[0084] θ i =4°~8° θ i Indicates the field change segment 1-3 half angle

[0085] d i =exp(1 / (2.5 K i a i )) / 4 (2)

[0086] Where d i represents the depth of the i-th slot;

[0087] Step 4: Considering cross polarization and high-frequency high-order mode suppression, design the feed mode transmission radiation section. The present invention adopts the same mode conversion section with unchanged opening angle, slot width and spacing, only changes the slot depth, and selects an appropriate length to meet the radiation pattern design requirements.

[0088] Step 5: According to the design size, use simulation software to simulate and verify the designed corrugated feed size. After multiple optimizations, the best size is obtained for processing. Figure 2 As shown, the connecting bracket is as Figure 3The simulation results of the corrugated feed pattern are shown in Figure 4 As shown, the simulation diagram of the corrugated feed source and the reflector surface is as follows Figure 5 The simulated radiation pattern of the reflector antenna is shown in Figure 6 shown.

[0089] Step 6: Use dual probe excitation to debug and test the electrical performance of the corrugated feed, and install a small reflective antenna on the surface for test verification. The three-view diagram of the actual dual-polarization corrugated feed structure is as follows: Figure 7 The bracket of the dual-polarization corrugated feed offset-fed small parabolic reflector antenna is shown in Figure 8 The three-view diagram of the structure of the dual-polarized corrugated feed installed on the reflector antenna is shown in Fig. 9 The actual antenna pattern test results are shown in Fig.10 .

[0090] The present invention designs a small parabolic reflector antenna, and designs a dual-polarized corrugated feed source that matches the small parabolic reflector antenna. The dual-polarized corrugated feed source is designed and simulated to adapt to the small parabolic reflector antenna, and both vertical and horizontal polarizations are realized at the same time, so that the indicators of the parabolic reflector antenna meet the indicator requirements for use. The dual-polarized corrugated feed source designed by the present invention mainly adopts a corrugated groove design, and its electromagnetic field distribution meets the illumination requirements of the small parabolic reflector antenna by setting certain parameters such as transition sections, corrugated grooves, and inclination angles. At the same time, the small parabolic reflector antenna adopts an offset feed design, so that the indicators such as the beam width and side lobes of the directional pattern of the small parabolic reflector antenna meet the use requirements.

Claims

1. A dual-polarized corrugated feed offset-fed small parabolic reflector antenna, characterized in that: It comprises a dual-polarization corrugated feed source (1), a connecting bracket (2), and a reflecting surface (3), wherein: The dual-polarization corrugated feed source (1) adopts a four-section structure design, and is designed in the order of a feeding section (1-1), a transition section (1-2), a field conversion section (1-3) and a radiation section (1-4). The transition section (1-2) and the field conversion section (1-3) adopt a gradual corrugation groove depth design, and the radiation section (1-4) adopts a center frequency wavelength quarter depth design. The connecting bracket (2) is used to fix the dual-polarization corrugated feed source (1) and the reflecting surface (3), so as to realize the requirement of bias feeding of the dual-polarization corrugated feed source (1) to the reflecting surface (3).

2. The dual-polarization corrugated feed offset-fed small parabolic reflector antenna according to claim 1, characterized in that: The connecting bracket (2) comprises a base (2-4), and a first bracket (2-1), a second bracket (2-2), and a third bracket (2-3) arranged in sequence on the upper surface of the base; The first bracket (2-1) fixes the transition section (1-2) of the dual-polarization corrugated feed source (1), and the second bracket (2-2) fixes the radiation section (1-4) of the dual-polarization corrugated feed source (1); The third bracket (2-3) is used to fix the reflecting surface (3).

3. The dual-polarization corrugated feed offset-fed small parabolic reflector antenna according to claim 2, characterized in that: The first bracket (2-1) and the second bracket (2-2) are capable of adjusting the inclination angle of the dual-polarization corrugated feed source (1), that is, adjusting the offset feeding angle of the dual-polarization corrugated feed source (1) to the reflection surface (3).

4. The dual-polarization corrugated feed offset-fed small parabolic reflector antenna according to claim 3, characterized in that: The third bracket (2-3) can move along the base relative to the second bracket (2-2) to adjust the distance between the reflection surface (3) and the dual-polarization corrugated feed (1), and fine-tune the focal length of the dual-polarization corrugated feed (1) relative to the reflection surface (3), so that the dual-polarization corrugated feed (1) is located at the focal length position of the reflection surface (3).

5. The dual-polarization corrugated feed offset-fed small parabolic reflector antenna according to claim 4, characterized in that: The gradual corrugation grooves of the transition section (1-2) and the field conversion section (1-3) in the dual-polarization corrugation feed source (1) are formed by electroforming and then machining.

6. The dual-polarization corrugated feed offset-fed small parabolic reflector antenna according to claim 5, characterized in that: The feeding section (1-1) of the dual-polarization corrugated feed source (1) is fed by inserting mutually perpendicular metal probes into a circular waveguide, thereby realizing dual polarization.

7. The dual-polarization corrugated feed offset-fed small parabolic reflector antenna according to claim 6, characterized in that: The dual-polarization corrugated feed (1) uses a length transition of three times the center frequency wavelength to achieve HE 11 Mode conversion.

8. The dual-polarization corrugated feed offset-fed small parabolic reflector antenna according to claim 7, characterized in that: The depth of the corrugation groove of the dual-polarization corrugation feed (1) is determined by a method of changing the depth as the inclination angle changes.

9. A design method for a dual-polarized corrugated feed offset-fed small parabolic reflector antenna according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: According to the lower limit of the design frequency, according to the excitation HE 11 The mode determines the radius of the circular waveguide, i.e. a ≥ C / (3.41)f L , where a is the radius of the circular waveguide, C is the speed of light, and f L is the lower limit of the design frequency, from which the diameter size of the feed section (1-1) is obtained; Step 2: Consider the excitation HE in the circular waveguide according to the upper and lower limits of the design center frequency. 11 The mode is used to determine the diameter and length of the circular waveguide transitioning to the first corrugated groove. The formula is as follows: a(z)=a i +(a1-a i )sin(πz / (2z t ))(1) Where a(z) is the waveguide diameter corresponding to the change in z, starting from 0 to z t , that is, the diameter of the circular waveguide is changing; z t is the length of the transition section (1-2), the shortest of which is one waveguide wavelength; a i is the initial circular waveguide radius; a1 is determined by K i a1=2.7~3.4, the wave number K of the ith frequency point i =2π / λ i ; Step 3: Considering cross polarization and mode conversion, the field conversion section (1-3) and radiation section (1-4) of the corrugated slot are designed. The design formula of the corrugated slot is determined by the following formula: a L+1 K is the radius at the end of the field transformation segment (1-3), i a L+1 >3.5;P i / λ i Indicates the slot spacing, P i / λ i <0.175; W i / P i Indicates the ratio of slot width to slot spacing, W i / P i ≥0.75;θ i Indicates the half angle of the field change segment (1-3), θ i =4°~8°; d i =exp(1 / (2.5 K i a i )) / 4(2) Where d i represents the depth of the i-th slot; Step 4: Considering cross polarization and high-order mode suppression of high frequency, design the radiation section (1-4); The opening angle of the radiation section (1-4) is the same as the opening angle of the field conversion section (1-3), the slot width and the slot spacing remain unchanged, only the slot depth is changed, and the length of 3 times the center frequency wavelength is selected to meet the radiation pattern design requirements; Step 5. According to the design size, the designed dual-polarization corrugated feed (1) size is simulated and verified using HFSS simulation software. After optimizing the groove depth, the half angle of the field conversion segment (1-3) and the number of corrugated grooves, the size of the optimal dual-polarization corrugated feed (1) is obtained. The dual-polarization corrugated feed (1) and the reflecting surface (3) are jointly simulated and verified using CST simulation software. After adjusting the focal length, the optimal result is obtained. The structural drawing is designed and processed according to the optimal result.

10. The design method of the dual-polarization corrugated feed offset-fed small parabolic reflector antenna according to claim 9, characterized in that: The following test verification steps are also included: By using mutually perpendicular metal probes for excitation, the dual-polarization corrugated feed source (1) and the reflecting surface (3) are fixed to the connecting bracket (2), and the electrical performance of the dual-polarization corrugated feed source (1) is debugged and tested.

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