Circular polarizer and circularly polarized horn antenna

Abstract

The application provides a circular polarizer and a circularly polarized horn antenna, the circular polarizer comprises a circular waveguide and a dielectric insert, the dielectric insert has two oppositely arranged first sides and two oppositely arranged second sides, two oppositely arranged insertion grooves are arranged on the inner wall of the circular waveguide, the two first sides of the dielectric insert are respectively inserted into the two insertion grooves, the plane where the dielectric insert is located is arranged at an angle with the polarization direction of the linearly polarized wave, the two second sides of the dielectric insert are both provided with V-shaped grooves, the openings of the two V-shaped grooves face opposite directions, the V-shaped groove has two oppositely arranged first inner walls, the projection of the first inner wall on the plane parallel to the dielectric insert is a smooth curve, and the tangent lines of the smooth curve at the two end points are parallel to the axial direction of the circular waveguide. The circular polarizer and the circularly polarized horn antenna provided by the application reduce the generation of high-order modes in the circular polarizer, improve the performance of the circular polarizer, and further improve the performance of the circularly polarized horn antenna.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of electromagnetic field and microwave technology, and more particularly relates to a circular polarizer and a circular polarized horn antenna. BACKGROUND

[0002] The polarization of an antenna is generally divided into circular polarization and linear polarization. When the angle between the polarization plane of a radio wave and the normal plane of the earth changes periodically from 0 to 360°, that is, the direction of the electric field changes with time while the size of the electric field remains unchanged, and the trajectory of the end of the electric field vector projects a circle on the plane perpendicular to the propagation direction, the polarization is called circular polarization. A circularly polarized antenna can receive any polarized incoming wave, and its radiated wave can also be received by any polarized antenna. Moreover, a circularly polarized antenna has rotational orthogonality, and the rotational direction of a polarized wave incident on a symmetric target (such as a plane or a sphere) is reversed. Electromagnetic waves with different rotational directions have a large numerical polarization isolation.

[0003] At present, the commonly used methods for generating circular polarization of a horn antenna include direct generation by the antenna structure (such as a spiral antenna), use of a circularly polarized waveguide converter, and use of a phase shifter to generate a phase difference of 90 degrees between orthogonal linear polarizations. In summary, the current circularly polarized horn antenna has a narrow axial ratio bandwidth and impedance bandwidth, a complex structure, and a high processing difficulty and cost. SUMMARY

[0004] The purpose of the embodiments of the present application is to provide a circular polarizer and a circularly polarized horn antenna to solve the technical problems of a narrow axial ratio bandwidth and impedance bandwidth and a complex structure of the circularly polarized horn antenna in the prior art.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is to provide a circular polarizer for converting an incident linearly polarized wave into a circularly polarized wave. The circular polarizer comprises a circular waveguide and a dielectric insert. The dielectric insert has two oppositely arranged first side edges and two oppositely arranged second side edges. Two insertion grooves are formed in the inner wall of the circular waveguide in a diametrically opposite arrangement. The two first side edges of the dielectric insert are respectively inserted into the two insertion grooves. The plane in which the dielectric insert is located is arranged at an angle to the polarization direction of the linearly polarized wave. V-shaped grooves are formed in the two second side edges of the dielectric insert. The openings of the two V-shaped grooves face in opposite directions. The V-shaped grooves have two diametrically opposite first inner walls. The projection of the first inner wall on a plane parallel to the dielectric insert is a smooth curve. The tangent lines of the smooth curve at its two end points are parallel to the axial direction of the circular waveguide.

[0006] Optionally, the inner wall of the V-shaped groove further comprises a second inner wall, which is arranged opposite the opening of the V-shaped groove. One of the first inner walls, the second inner wall, and the other first inner wall are connected in sequence.

[0007] Optionally, the smooth curve satisfies the function The origin of the function f(x) is located at the midpoint of the second inner wall, and the smooth curve is located in the first quadrant, wherein a2 is the diameter of the circular waveguide, a1 is half of the length of the second inner wall, the size of the smooth curve in the axial direction of the circular waveguide is l, and 0≤x≤l.

[0008] Optionally, a1 is (0.5±0.02) mm.

[0009] Optionally, the angle between the plane where the dielectric insert is located and the polarization direction of the linearly polarized wave is (45±5)°.

[0010] Optionally, the dielectric insert is provided with a substrate integrated waveguide at each of the two first side edges.

[0011] Optionally, the substrate integrated waveguide comprises two metal sheets clamped on opposite sides of the dielectric insert and a plurality of metal columns arranged in sequence along the length direction of the first side edge, the metal columns are arranged through the dielectric insert, and the two ends of each metal column are respectively connected in conduction with the two metal sheets.

[0012] Optionally, the circular waveguide comprises two half waveguides formed in two parts, the cross section of the half waveguide is semicircular, a half slot is formed on the half waveguide, and the half slots of the two half waveguides jointly form the slot.

[0013] The application further provides a circularly polarized horn antenna, comprising the circular polarizer, and further comprising a waveguide converter and a horn radiator, the waveguide converter and the horn radiator are respectively connected to the incident end and the outgoing end of the circular polarizer, the waveguide converter is used for connecting a rectangular waveguide and the circular waveguide, and the horn radiator is used for radiating the circularly polarized wave generated by the circular polarizer.

[0014] Optionally, the waveguide converter is a multi-stage stepped waveguide converter, and the horn radiator is a circular conical corrugated horn radiator, a circular conical horn radiator or a pyramid horn radiator.

[0015] The circular polarizer and the circularly polarized horn antenna have the following advantages: compared with the prior art, the circular polarizer comprises a circular waveguide and a dielectric insert, two slots are formed in the inner wall of the circular waveguide, the two sides of the dielectric insert are respectively inserted into the two slots, V-shaped grooves are formed in the two second side edges of the dielectric insert, the projection of the first inner wall of the V-shaped groove on the plane parallel to the dielectric insert is a smooth curve, and the tangent lines at the two end points of the smooth curve are parallel to the axial direction of the circular waveguide, thereby reducing the generation of high-order modes in the circular polarizer, improving the performance of the circular polarizer, and further improving the performance of the circularly polarized horn antenna. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0017] Figure 1 A three-dimensional structural diagram of a circular polarizer provided in an embodiment of the present invention;

[0018] Figure 2 A cross-sectional view of a circular polarizer provided in an embodiment of the present invention;

[0019] Figure 3 A longitudinal cross-sectional view of a circular polarizer provided by an embodiment of the present invention (dielectric insert perspective view);

[0020] Figure 4 An exploded structural diagram of a circular polarizer provided in an embodiment of the present invention;

[0021] Figure 5 A front view of a dielectric insert provided by an embodiment of the present invention;

[0022] Figure 6 A diagram showing the simulated return loss results of a circular polarizer provided in an embodiment of the present invention;

[0023] Figure 7 The E of the circular polarizer provided in the embodiment of the present invention x and E y Amplitude difference simulation result diagram;

[0024] Figure 8 The E of the circular polarizer provided in the embodiment of the present invention x and E y Phase difference simulation result diagram;

[0025] Figure 9 A three-dimensional structural diagram of a circularly polarized horn antenna provided in an embodiment of the present invention;

[0026] Figure 10 A three-dimensional structural diagram of a waveguide converter provided in an embodiment of the present invention;

[0027] Figure 11 A three-dimensional structural diagram of a horn radiator provided in an embodiment of the present invention;

[0028] Figure 12 The simulated return loss and tested return loss diagrams of the circularly polarized horn antenna provided in an embodiment of the present invention;

[0029] Figure 13An axial ratio and gain simulation result diagram of the circularly polarized horn antenna provided by the embodiment of the present application is shown in the figure;

[0030] Figure 14 A directional diagram simulation result diagram of the circularly polarized horn antenna provided by the embodiment of the present application at 20GHz is shown in the figure;

[0031] Figure 15 A directional diagram simulation result diagram of the circularly polarized horn antenna provided by the embodiment of the present application at 24GHz is shown in the figure;

[0032] Figure 16 A directional diagram simulation result diagram of the circularly polarized horn antenna provided by the embodiment of the present application at 30GHz is shown in the figure.

[0033] In the figure, various reference signs are as follows:

[0034] 1-circular polarizer; 11-circular waveguide; 111-half waveguide; 112-slot; 1121-half slot; 12-medium insert; 121-first side; 122-second side; 123-V-shaped slot; 124-first inner wall; 125-second inner wall; 13-substrate integrated waveguide; 132-metal sheet; 131-metal column; 2-waveguide converter; 21-step structure; 22-circular connecting part; 3-horn radiator. DETAILED DESCRIPTION

[0035] In order to make the technical problems to be solved by the present application, the technical solutions and the beneficial effects more clearly understood, the present application 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 only used to explain the present application and not intended to limit the present application.

[0036] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0037] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "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 drawings, and are only used to facilitate the description of the present application and simplify the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0038] In addition, the terms "first", "second", "third", etc. are used herein only to describe different instances, and are not used to indicate or imply relative importance or a number of indicated technical features. Thus, features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0039] The circular polarizer 1 provided by the embodiment of the present application will be described.

[0040] Please refer to Figures 1 to 4 , Figure 1 The perspective view of the circular polarizer 1 provided by the embodiment of the present application, Figure 2 The cross-sectional view of the circular polarizer 1 provided by the embodiment of the present application, Figure 3 The longitudinal sectional view of the circular polarizer 1 provided by the embodiment of the present application (perspective of the dielectric insert 12), Figure 4 The exploded view of the circular polarizer 1 provided by the embodiment of the present application. The circular polarizer 1 is used to convert the incident linearly polarized wave into circularly polarized wave, thus, the performance of the circular polarizer 1 will directly affect the performance of the circularly polarized horn antenna. The circular polarizer 1 includes a circular waveguide 11 and a dielectric insert 12, the circular waveguide 11 has a cylindrical cavity, and the circular waveguide 11 is made of metal material at least at the inner wall of the cylindrical cavity. The direction from the incident end to the outgoing end of the circular polarizer 1 is the ox direction. Two insertion slots 112 are arranged opposite to each other at the inner wall of the circular waveguide 11, the length direction of the two insertion slots 112 is parallel to the ox direction, and the two sides of the dielectric insert 12 are respectively inserted into the corresponding two insertion slots 112.

[0041] Please refer to Figure 5 , Figure 5 The front view of the dielectric insert 12 provided by the embodiment of the present application, the dielectric insert 12 has two first side edges 121 arranged opposite to each other and two second side edges 122 arranged opposite to each other, and the two first side edges 121 and the two second side edges 122 together enclose the outer peripheral wall of the dielectric insert 12. The two first side edges 121 of the dielectric insert 12 are respectively inserted into the two insertion slots 112. The dielectric insert 12 is used as a phase shift element, the dielectric insert 12 is fixed inside the circular waveguide 11, and the plane where the dielectric insert 12 is located is arranged at an angle with the incident linearly polarized wave. As shown in Figure 2 When the incident wave E is incident from the incident end of the circular polarizer 1, the incident wave E is decomposed into two in-phase orthogonal polarization components E x and E y . x and E yWhen passing through the dielectric plug 12 of the circular polarizer 1, the dielectric plug 12 generates two phase shift constants for the two orthogonal polarization components respectively. By adjusting the shape of the dielectric plug 12, the two orthogonal polarization components can be made to have a phase difference of 90°, thereby converting linearly polarized waves into circularly polarized waves.

[0042] Specifically, the two second side edges 122 of the dielectric plug 12 are each provided with a V-shaped groove 123, the two V-shaped grooves 123 have opposite vertices, and the openings of the two V-shaped grooves 123 face opposite directions. The opening of one of the V-shaped grooves 123 faces the incident end of the circular polarizer 1, and the opening of the other V-shaped groove 123 faces the outgoing end of the circular polarizer 1. The V-shaped groove 123 has two first inner walls 124 arranged opposite to each other, and the distance between the two first inner walls 124 gradually decreases from the opening end of the V-shaped groove 123 to the vertex. The projection of the first inner wall 124 on the plane parallel to the dielectric plug 12 is a smooth curve, that is, the projection of the first inner wall 124 on the xoy plane is a smooth curve. The tangent lines of the smooth curve at the two end points thereof are parallel to the axial direction of the circular waveguide 11, and the axial direction of the circular waveguide 11 is parallel to the ox direction, so that the generation of high-order modes in the circular polarizer 1 can be reduced, the performance of the circular polarizer 1 is improved, and the circular polarized horn antenna has a wider impedance bandwidth, a wider axial ratio bandwidth, and a wider application range.

[0043] The circular polarizer 1 in the above embodiment includes the circular waveguide 11 and the dielectric plug 12, the inner wall of the circular waveguide 11 is provided with two insertion grooves 112, the two sides of the dielectric plug 12 are respectively inserted into the two insertion grooves 112, the two second side edges 122 of the dielectric plug 12 are each provided with a V-shaped groove 123, the projection of the first inner wall 124 of the V-shaped groove 123 on the plane parallel to the dielectric plug 12 is a smooth curve, and the tangent lines of the smooth curve at the two end points thereof are parallel to the axial direction of the circular waveguide 11, so that the generation of high-order modes in the circular polarizer 1 can be reduced, the performance of the circular polarizer 1 is improved, and the performance of the circular polarized horn antenna is improved.

[0044] In one of the embodiments of the present application, please refer to Figure 5 The inner wall of the V-shaped groove 123 further includes a second inner wall 125, the second inner wall 125 is arranged opposite to the opening of the V-shaped groove 123, and the second inner wall 125 can be regarded as the bottom wall of the V-shaped groove 123. One of the first inner walls 124, the second inner wall 125 and the other inner wall are sequentially connected. The second inner wall 125 can be parallel to the second side edge 122. The arrangement of the second inner wall 125 separates the two first inner walls 124 from each other, so that the sharp corners formed at the connection between the two first inner walls 124 can be avoided, the circular polarizer 1 can be easily processed, and the performance of the circular polarizer 1 can be improved.

[0045] In one of the embodiments of the present application, please refer to Figure 5The two second side edges 122 of the dielectric plug 12 are provided with V-shaped grooves 123, that is, there are two V-shaped grooves 123, and each V-shaped groove 123 has two first inner walls 124, so that the number of the first inner walls 124 of the dielectric plug 12 is four, and the number of the smooth curves in the projection on the xoy plane is also four.

[0046] In one embodiment, the smooth curve satisfies the following function: The origin of the function is located at the midpoint of the second inner wall 125, and the smooth curve is always located in the first quadrant. Specifically, in combination with Figure 5 The origin of the coordinate system corresponding to the smooth curve on the upper right side is located at the midpoint of the second inner wall 125 on the right side, the positive direction of the x-axis of the coordinate system is to the right, and the positive direction of f(x) is upward. The origin of the coordinate system corresponding to the smooth curve on the lower right side is located at the midpoint of the second inner wall 125 on the right side, the positive direction of the x-axis of the coordinate system is to the right, and the positive direction of f(x) is downward. The origin of the coordinate system corresponding to the smooth curve on the upper left side is located at the midpoint of the second inner wall 125 on the left side, the positive direction of the x-axis of the coordinate system is to the left, and the positive direction of f(x) is upward. The origin of the coordinate system corresponding to the smooth curve on the lower left side is located at the midpoint of the second inner wall 125 on the left side, the positive direction of the x-axis of the coordinate system is to the left, and the positive direction of f(x) is downward. Wherein, a2 is the diameter of the circular waveguide 11, a1 is half of the length of the second inner wall 125, the size of the smooth curve in the axial direction of the circular waveguide 11 is l, and 0≤x≤l.

[0047] In this way, the derivative of f(x) is Therefore, the derivative of f(x) at x=0 or x=l is 0, that is, the tangent at the two endpoints of the smooth curve is parallel to the axial direction of the circular waveguide 11, so as to reduce the generation of high-order modes.

[0048] In another embodiment, the smooth curve satisfies the following function: The origin of the function is located at the midpoint of the second inner wall 125, and the smooth curve is always located in the first quadrant. The derivative of the function is Therefore, the derivative of f(x) at x=0 or x=l is 0, that is, the tangent at the two endpoints of the smooth curve is parallel to the axial direction of the circular waveguide 11, so as to reduce the generation of high-order modes.

[0049] It should be noted that each smooth curve on the dielectric plug 12 can satisfy any one of the above functions, or can be a sine function, a square function, etc. The function corresponding to the smooth curve is When f(x)=a2x, the axial ratio of the circular polarizer 1 in the same bandwidth is lower, and the circular polarization effect is better.

[0050] Optionally, a1 is (0.5±0.02) mm. If a1 is too small, the length of the second inner wall 125 is too short, which is not easy to process. If a1 is too large, the size of the smooth curve in the oy direction is limited, which causes the function corresponding to the smooth curve not easy to construct, and the performance of the circular polarizer 1 is affected to a certain extent. Therefore, a1 is set to (0.5±0.02) mm.

[0051] In one embodiment of the present application, referring to Figure 2 , the angle between the plane where the dielectric insert 12 is located and the polarization direction of the linearly polarized wave is (45±5)°, such as 42°, 43°, 45°, 48°, etc. When the angle between the plane where the dielectric insert 12 is located and the polarization direction of the linearly polarized wave is 45±5°, the incident wave E is decomposed into two orthogonal polarization components E x and E y in the horizontal direction and the vertical direction, and the amplitudes of the two are relatively close. In this way, after being converted into a circularly polarized wave, the component amplitudes in the X direction and the Y direction are relatively close, and the axial ratio of the circularly polarized wave is closer to 1. Optionally, the angle between the plane where the dielectric insert 12 is located and the polarization direction of the linearly polarized wave is 45°, so that the component amplitudes of the circularly polarized wave in the X direction and the Y direction are relatively close, and the axial ratio of the circularly polarized wave is closer to 1.

[0052] In one embodiment of the present application, referring to Figure 3 and Figure 4 , the dielectric insert 12 is provided with a substrate integrated waveguide 13 at each of the two first side edges 121. In the embodiment of the present application, the inner wall of the circular waveguide 11 is provided with a slot 112 for fixing the dielectric insert 12. Since the slot 112 is opened in the inner wall of the circular waveguide 11, it will destroy the symmetry of the circular polarizer 1, thereby affecting the performance of the circular polarizer 1. In the prior art, a compensation slot is opened in the inner wall of the circular waveguide 11, and the size of the compensation slot is adjusted to offset the influence of the slot 112 on the circular polarizer 1. However, the depth of the compensation slot has a great influence on the performance of the circular polarizer 1, which requires high processing precision of the compensation slot. Once there is a large processing error, the performance of the circular polarizer 1 will be deteriorated sharply, and the circular polarizer 1 cannot be used. In the embodiment of the present application, in view of this problem, the dielectric insert 12 is provided with a substrate integrated waveguide 13 at each of the two first side edges 121. Since the first side edge 121 is inserted into the slot 112, the substrate integrated waveguide 13 is arranged on the side of the slot 112 facing the inner cavity of the circular waveguide 11. The substrate integrated waveguide 13 is equivalent to a metal wall, which can offset the influence of the slot 112 on the performance of the circular polarizer 1.

[0053] In one embodiment of the present application, referring to Figure 3 and Figure 4The substrate integrated waveguide 13 comprises two metal sheets 132 and a plurality of metal columns 131. The two metal sheets 132 are arranged on opposite sides of the dielectric insert 12 respectively, and the plurality of metal columns 131 are arranged through the dielectric insert 12 and sequentially arranged along the length direction of the first side 121. The two ends of each metal column 131 are connected to the two metal sheets 132 respectively. When the number of the metal columns 131 is sufficient, the gap between the adjacent metal columns 131 is small, and the metal column 131 and the metal sheet 132 are matched to make the gap equivalent to a metal wall, so that the cylindrical inner wall of the circular waveguide 11 with the slot 112 is equivalent to the cylindrical inner wall without the slot as much as possible.

[0054] Optionally, the metal column 131 can be a hollow column or a solid column, as long as the surface is a metal material. The cross section of the metal column 131 can be circular, square, triangular, etc., and the shape of the cross section is not limited here.

[0055] Compared with the metal wall formed in the dielectric insert 12, the substrate integrated waveguide 13 is easier to manufacture.

[0056] Optionally, the dielectric insert 12 is also provided with a metal column 131 at the second side 122, and the two ends of the metal column 131 are connected to the two metal sheets 132 respectively. The metal column 131 at the second side 122 blocks the end of the slot 112, so that the metal wall blocking the slot 112 can be better formed.

[0057] In one embodiment of the present application, please refer to Figure 4 The circular waveguide 11 comprises two half waveguides 111, and the two half waveguides 111 are formed separately. The cross section of each half waveguide 111 is semicircular, and the two half waveguides 111 are combined to form the circular waveguide 11. The two half waveguides 111 are provided with half slots 1121, and the two half slots 1121 are combined to form the slot 112 when the two half waveguides 111 are combined to form the circular waveguide 11, so as to insert the dielectric insert 12.

[0058] The circular waveguide 11 is formed by two half waveguides 111, which is more convenient for the processing, surface metal layer plating and other processes of the circular waveguide 11, and the processing cost is lower. It is also more convenient for the installation of the dielectric insert 12.

[0059] In other embodiments, the circular waveguide 11 can also be integrally formed by 3-D printing.

[0060] In order to verify the circular polarizer 1 provided by the present application, the circular polarizer 1 in Figure 4 is modeled and simulated in CST, and the simulation results are as follows: Figure 6 ​Figure 4 Simulation result diagram of return loss of the circular polarizer 1;

[0061] Figure 7 For Figure 4 E x and E y Simulation result diagram of amplitude difference; Figure 8 For Figure 1 E x and E y Simulation result diagram of phase difference. Right Figures 6 to 9 It can be known that the circular polarizer 1 has low return loss.

[0062] Please refer to Figures 9 to 11 The application further provides a circularly polarized horn antenna, which comprises the circular polarizer 1 in any of the above embodiments, and further comprises a waveguide converter 2 and a horn radiator 3. The waveguide converter 2 is used for connecting a rectangular waveguide and the circular waveguide 11, and the horn radiator 3 is used for radiating the circularly polarized wave generated by the circular polarizer 1. The waveguide converter 2 and the horn radiator 3 are respectively connected to the incident end and the outgoing end of the circular polarizer 1, electromagnetic waves are transmitted to the circular polarizer 1 through the rectangular waveguide flange, the circular polarizer 1 converts linearly polarized waves into circularly polarized waves, and then the horn radiator 3 radiates outward.

[0063] The circularly polarized horn antenna provided by the application adopts the above-mentioned circular polarizer 1, the circular polarizer 1 comprises a circular waveguide 11 and a dielectric insert 12, two insertion grooves 112 are formed in the inner wall of the circular waveguide 11, the two sides of the dielectric insert 12 are respectively inserted into the two insertion grooves 112, V-shaped grooves 123 are formed in the two second side edges 122 of the dielectric insert 12, the projection of the first inner wall 124 of the V-shaped groove 123 on the plane parallel to the dielectric insert 12 is a smooth curve, the tangent lines of the smooth curve at the two end points are parallel to the axial direction of the circular waveguide 11, the generation of high-order modes in the circular polarizer 1 is reduced, the performance of the circular polarizer 1 is improved, and the performance of the circularly polarized horn antenna is improved.

[0064] In one of the embodiments of the application, please refer to Figure 10 Since the standard flange is a rectangular waveguide, and the corresponding waveguide of the circular polarizer 1 is a circular waveguide 11, a structure for converting a rectangular waveguide into a circular waveguide 11 needs to be designed, that is, the waveguide converter 2 is arranged, so that the standard flange (rectangular waveguide) can be connected to the circular polarizer 1 through the waveguide converter 2.

[0065] Optionally, the waveguide converter 2 is a multi-stage stepped waveguide converter, the number of stages of which is not limited here and can be four, five, etc. The more the number of stages of the stepped waveguide converter 2, the more complex the process, the higher the processing difficulty, and the better the conversion effect. Correspondingly, the fewer the number of stages of the stepped waveguide converter 2, the simpler the process, the lower the processing difficulty, and the worse the conversion effect.

[0066] Optionally, the multi-stage stepped waveguide converter 2 includes a stepped structure 21 and a circular connecting part 22. The number of stages of the stepped structure 21 is the number of stages of the multi-stage stepped waveguide converter. The circular connecting part 22 is connected with the circular waveguide 11. The stepped structure 21 is internally rectangular, and the four corners of the internal rectangle are all rounded to improve the matching degree of the waveguide converter 2.

[0067] In one of the embodiments of the present application, please refer to Figure 11 The horn radiator 3 is a conical corrugated horn radiator 3, a conical horn radiator 3, or a pyramidal horn radiator 3.

[0068] Optionally, when the circularly polarized horn antenna is assembled and formed, the horn radiator 3, the circular polarizer 1, and the multi-stage stepped waveguide converter 2 are sequentially connected, and a flange is also fixed on the waveguide converter 2. The circularly polarized horn antenna is of metal material except the dielectric insert 12 and can be processed by milling and washing. The whole is also processed in three parts, i.e., the horn radiator 3, the circular polarizer 1, and the waveguide converter 2, respectively. Then, the processed parts are assembled by screws, and the flange is fixed on the waveguide converter 2 by screws. The circular polarizer 1 is processed by being cut into two halves (two half waveguides 111) from the middle and then assembled into a complete circular polarizer 1 by screws. The radius of the inner wall of the narrow end of the horn radiator 3 is equal to the radius of the inner wall of the circular polarizer 1, and the radius of the circular cross section of the inner wall of the waveguide converter 2 is equal to the radius of the circular cross section of the inner wall of the circular polarizer 1.

[0069] In order to verify the circularly polarized horn antenna proposed in the present application, the circularly polarized horn antenna in Figure 9 is modeled and simulated in CST, and the physical processing and testing are also performed. The simulation and testing results are as follows: Figure 12 is Figure 9 the simulation and testing return loss graphs of the circularly polarized horn antenna; Figure 13 is Figure 9 the simulation results graphs of the axial ratio and gain of the circularly polarized horn antenna; Figures 14 to 16 is Figure 9 the simulation results graphs of the directional pattern of the circularly polarized horn antenna, Figure 14 is the directional pattern of the antenna at 20 GHz, Figure 15 is the directional pattern of the antenna at 24 GHz, Figure 15 is the directional pattern of the antenna at 30 GHz. From the above simulation and testing results, it can be seen that the circularly polarized horn antenna proposed in the present application has a good circular polarization performance and a good directional pattern.Figures 12 to 16 It can be known that the circularly polarized horn antenna has wider impedance bandwidth, wider axial ratio bandwidth and wider application range.

[0070] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A circular polarizer for converting an incident linearly polarized wave into a circularly polarized wave, characterized by: It includes a circular waveguide and a dielectric insert, the dielectric insert has two oppositely arranged first side edges and two oppositely arranged second side edges, the inner wall of the circular waveguide is provided with two oppositely arranged slots, the two first side edges of the dielectric insert are respectively inserted into the two slots, the plane where the dielectric insert is located is arranged at an angle to the polarization direction of the linearly polarized wave, the two second side edges of the dielectric insert are both provided with a V-shaped groove, the openings of the two V-shaped grooves face oppositely, the V-shaped groove has two oppositely arranged first inner walls, the inner wall of the V-shaped groove further includes a second inner wall, the second inner wall is arranged opposite to the opening of the V-shaped groove, one of the first inner walls, the second inner wall and the other first inner wall are connected in sequence, the projection of the first inner wall on a plane parallel to the dielectric insert is a smooth curve, and the tangents of the smooth curve at its two end points are parallel to the axial direction of the circular waveguide; the smooth curve satisfies the function ,function The origin of is located at the midpoint of the second inner wall, and the smooth curve is located in the first quadrant, wherein, a 2 is the diameter of the circular waveguide, a 1 is half the length of the second inner wall, and the dimension of the smooth curve in the axial direction of the circular waveguide is , a 1 is (0.5±0.02) mm, and the tangents of the smooth curve at its two end points are parallel to the axial direction of the circular waveguide, so as to reduce the generation of high-order modes.

2. The circular polarizer of claim 1, wherein: An angle between a plane where the dielectric insert is located and a polarization direction of the linearly polarized wave is (45±5)°.

3. The circular polarizer of any of claims 1-2, wherein: The dielectric insert is provided with a substrate integrated waveguide at both of the first side edges.

4. The circular polarizer of claim 3, wherein: The substrate integrated waveguide comprises two metal sheets clamped on opposite sides of the dielectric insert and a plurality of metal columns arranged in sequence along the length direction of the first side edge, the metal columns penetrating through the dielectric insert and both ends of each metal column being connected to the two metal sheets.

5. The circular polarizer of any of claims 1-2, wherein: The circular waveguide comprises two half waveguides formed in two parts, the half waveguides having a semicircular cross section, a half slot being formed on each half waveguide, and the half slots of the two half waveguides together forming the slot.

6. A circularly polarized horn antenna, characterized by: The circular polarizer comprises a waveguide converter and a horn radiator, the waveguide converter and the horn radiator being connected to the incident end and the outgoing end of the circular polarizer respectively, the waveguide converter being used to connect a rectangular waveguide and the circular waveguide, and the horn radiator being used to radiate the circularly polarized wave generated by the circular polarizer.

7. The circularly polarized horn antenna of claim 6, wherein: The waveguide converter is a multi-stage stepped waveguide converter, and the horn radiator is a circular conical corrugated horn radiator, a circular conical horn radiator or a pyramid horn radiator.

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