Multi-beam planar antenna

Abstract

The embodiment of the present application provides a kind of multi-beam planar antenna, it is related to communication equipment technical field.Multi-beam planar antenna includes the feed for radiating electromagnetic wave, Cassegrain beam former and lens.Cassegrain beam former is arranged in the radiation direction of electromagnetic wave of feed, Cassegrain beam former has Cassegrain primary reflector and the first metal parallel plate group being arranged in the electromagnetic wave emission direction of Cassegrain primary reflector.Lens is arranged in the first metal parallel plate group, the arc surface of lens is away from the side of Cassegrain primary reflector, and lens is used for correcting the phase of multi-beam planar antenna aperture field, to make aperture field phase distribution tend to linear distribution.Thereby can reduce side lobe level and improve gain, aperture efficiency realizes good beam radiation performance in wide angle scanning range.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of radio frequency antennas, and in particular to a multi-beam planar antenna. BACKGROUND

[0002] One of the key technologies of mobile communication is millimeter wave multi-beam antenna technology. The reflector antenna based on quasi-optical beam forming mechanism has the advantages of simple structure, high radiation efficiency, etc., and is often used to realize multi-beam radiation.

[0003] However, for multi-beam reflector antennas, due to the increased feed blockage effect and transverse defocusing effect, the radiation performance of the scanning beam will deteriorate, greatly limiting the scanning range of the multi-beam reflector antenna. SUMMARY

[0004] The purposes of the present application include, for example, providing a multi-beam planar antenna capable of improving the radiation performance of the beam and realizing multi-beam coverage in a large angle range.

[0005] Embodiments of the present application can be implemented as follows:

[0006] In a first aspect, the present application provides a multi-beam planar antenna, comprising:

[0007] a feed source for radiating electromagnetic waves;

[0008] a Cassegrain beam former disposed in the direction of the radiated electromagnetic waves of the feed source, the Cassegrain beam former having a Cassegrain primary reflector and a first set of metal parallel plates disposed in the direction of the electromagnetic waves of the Cassegrain primary reflector; and

[0009] a lens disposed in the first set of metal parallel plates, the lens having an arc-shaped surface on the side away from the Cassegrain primary reflector, the lens being used to correct the phase of the aperture field of the multi-beam planar antenna so that the phase distribution of the aperture field tends to be linear.

[0010] In an optional embodiment, the lens is a homogeneous dielectric plate.

[0011] In an optional embodiment, the lens comprises a plurality of metal columns, the plurality of metal columns being two-dimensionally and periodically distributed, and the metal columns located at the outer periphery of the plurality of metal columns forming the arc-shaped surface on the side away from the Cassegrain primary reflector.

[0012] In an optional embodiment, the plurality of metal columns are integrally formed with one of the metal parallel plates.

[0013] In an optional embodiment, the arc-shaped surface is convex towards the side away from the Cassegrain primary reflector, the sweep line of the arc-shaped surface is a conic curve, and the sweep line of the Cassegrain primary reflector is a parabolic curve.

[0014] In an optional embodiment, the sweep line of the arc-shaped surface satisfies the following formula:

[0015]

[0016] L3 represents the eccentricity of the conic curve, p represents the focal length of the conic curve, z represents the longitudinal coordinate in the coordinate system with the vertex of the sweep line of the Cassegrain primary reflector as the coordinate origin, and y represents the transverse coordinate in the coordinate system with the vertex of the sweep line of the Cassegrain primary reflector as the coordinate origin, wherein the coordinate axis of the transverse coordinate is the tangent line of the Cassegrain primary reflector passing through the vertex, and the coordinate axis of the longitudinal coordinate is the symmetry axis of the sweep line of the Cassegrain primary reflector.

[0017] In an optional embodiment, the side of the lens close to the Cassegrain primary reflector is a straight surface.

[0018] In an optional embodiment, the height of the lens decreases from the center of the lens towards the side close to the Cassegrain primary reflector and the side away from the Cassegrain primary reflector, respectively.

[0019] In an optional embodiment, the feed source comprises a plate end connector, a waveguide array short circuit end, a feed network and a waveguide array arranged in sequence, and the plate end connector is used for antenna signal input;

[0020] The beam former further has a second metal parallel plate group, a third metal parallel plate group and a Cassegrain secondary reflector, the first metal parallel plate group, the second metal parallel plate group and the third metal parallel plate group are arranged in parallel two by two, the Cassegrain secondary reflector is formed at one end of the second metal parallel plate group and the third metal parallel plate group, the Cassegrain primary reflector is formed between the second metal parallel plate group and the first metal parallel plate group, and the Cassegrain secondary reflector and the Cassegrain primary reflector are arranged oppositely, the third parallel plate is arranged in the electromagnetic wave radiation path of the waveguide array, and the electromagnetic wave radiated by the waveguide array enters the second metal parallel plate group after being reflected by the Cassegrain secondary reflector, and the radiated electromagnetic wave entering the second metal parallel plate group is reflected by the Cassegrain primary reflector to the first metal parallel plate group;

[0021] The spacing of the third parallel metal plate decreases from the middle towards the two sides of the waveguide array and the Cassegrain secondary reflector, respectively.

[0022] In an optional embodiment, the multi-beam planar antenna further comprises a radiation structure arranged on a side from which the metal parallel plate group radiates a beam, and the radiation structure is arranged at an angle with the first metal parallel plate group, the radiation structure is a metal plate group that opens, and the metal plate group opens in a direction away from the first metal parallel plate group, and the opening increases.

[0023] The multi-beam planar antenna provided by the embodiments of the present application has the following beneficial effects:

[0024] Since the beam scanning of the reflecting surface is realized by transverse defocusing of the feed, a large transverse defocusing distance will cause a nonlinear phase distribution of the aperture field of the multi-beam planar antenna, thereby reducing the radiation performance of the antenna. The lens arranged in the first metal parallel plate group can improve the phase in the aperture field, so that the nonlinear phase distribution tends to be linear, thereby reducing the sidelobe level and improving the gain and aperture efficiency to achieve good beam radiation performance in a wide-angle scanning range. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0026] Figure 1 The structure schematic diagram of the multi-beam planar antenna provided by the embodiments of the present application is shown in the following figure:

[0027] Figure 2 The longitudinal sectional structure schematic diagram of the multi-beam planar antenna provided by the embodiments of the present application is shown in the following figure:

[0028] Figure 3 The transverse sectional structure schematic diagram of the multi-beam planar antenna provided by the embodiments of the present application is shown in the following figure:

[0029] Figure 4 The internal ray trajectory diagram of the multi-beam planar antenna provided by the embodiments of the present application is shown in the following figure:

[0030] Figure 5 The reflection coefficient result diagram of the first part of ports of the multi-beam planar antenna provided by the embodiments of the present application is shown in the following figure:

[0031] Figure 6 The reflection coefficient result diagram of the second part of ports of the multi-beam planar antenna provided by the embodiments of the present application is shown in the following figure:

[0032] Figure 7A reflection coefficient result graph of a third part port of the multi-beam planar antenna provided by the embodiment of the present application is shown in the figure;

[0033] Figure 8 A simulation and measurement result graph of the multi-beam planar antenna provided by the embodiment of the present application at a 28G frequency point is shown in the figure;

[0034] Figure 9 A simulation and measurement result graph of the multi-beam planar antenna provided by the embodiment of the present application at a 34G frequency point is shown in the figure;

[0035] Figure 10 A simulation and measurement result graph of the multi-beam planar antenna provided by the embodiment of the present application at a 40G frequency point is shown in the figure;

[0036] Figure 11 A gain result graph of a first part port of the multi-beam planar antenna provided by the embodiment of the present application is shown in the figure;

[0037] Figure 12 A gain result graph of a second part port of the multi-beam planar antenna provided by the embodiment of the present application is shown in the figure;

[0038] Figure 13 A -3dB beam projection graph of the multi-beam planar antenna provided by the embodiment of the present application is shown in the figure;

[0039] Figure 14 A double-antenna structure and coverage schematic diagram of the multi-beam planar antenna provided by the embodiment of the present application is shown in the figure.

[0040] Icon: 100-multi-beam planar antenna; 110-feed source; 111-plate end connector; 113-waveguide array short circuit end; 115-feed network; 117-waveguide array; 130-Cassegrain beam former; 131-Cassegrain main reflector; 133-first metal parallel plate group; 135-second metal parallel plate group; 137-third metal parallel plate group; 139-Cassegrain sub-reflector; 150-lens; 151-arc surface; 153-metal column; 155-straight surface; 170-radiation structure. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the application provided in the accompanying drawings is not intended to limit the scope of the application claimed, but merely represents selected embodiments of the application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the application, without making creative efforts, fall within the scope of the application claimed.

[0043] It should be noted that similar reference numbers and letters represent similar items in the following drawings, and therefore, once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings.

[0044] In the description of the application, it should be noted that if the terms "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the application is usually placed, and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0045] In addition, if the terms "first", "second" and the like appear, they are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0046] It should be noted that the features in the embodiments of the application can be combined with each other without conflict.

[0047] Please refer to Figure 1 The embodiment provides a multi-beam planar antenna 100, which comprises a feed source 110 for radiating electromagnetic waves, a Cassegrain beam former 130 and a lens 150. The Cassegrain beam former 130 is arranged in the direction of the radiated electromagnetic waves of the feed source 110, and the Cassegrain beam former 130 has a Cassegrain primary reflector 131 and a first metal parallel plate group 133 arranged in the direction of the electromagnetic waves of the Cassegrain primary reflector 131. The lens 150 is arranged in the first metal parallel plate group 133, and the side of the lens 150 away from the Cassegrain primary reflector 131 is an arc surface 151. The lens 150 is used for correcting the phase of the aperture field of the multi-beam planar antenna 100, so that the phase distribution of the aperture field tends to be linear.

[0048] Since the beam scanning of the reflector is achieved by transversely defocusing the feed 110, a large transverse defocusing distance will cause a nonlinear phase distribution of the aperture field of the multi-beam planar antenna 100, thereby reducing the radiation performance of the antenna. The lens 150 is arranged in the first parallel metal plate group in the present application, which can improve the phase in the aperture field, so that the nonlinear phase distribution tends to be linear, thereby reducing the sidelobe level and improving the gain and aperture efficiency to achieve good beam radiation performance in a wide-angle scanning range. A single antenna structure or a double antenna structure is used to form one or two groups of wide-angle scanning sector beams, thereby realizing radio wave coverage in a large angle range.

[0049] It should be noted that the aperture field is the electric field on the antenna aperture surface, and the aperture surface is the last surface of the antenna.

[0050] Specifically, the lens 150 is used to reduce the standard deviation between the aperture field phase distribution and the ideal linear phase distribution at the same scanning angle, so that the aperture field phase distribution tends to be linear, thereby avoiding the beam performance deterioration problem caused by high-order phase error and improving the wide-angle scanning beam radiation performance. The standard deviation of the antenna aperture field phase distribution relative to the ideal linear distribution is represented as:

[0051]

[0052] wherein φ (y) is the antenna aperture field phase distribution, φ0(y) is the ideal linear phase distribution at the same scanning angle, n is the number of aperture surface discrete points, y i is the abscissa of the aperture surface corresponding point.

[0053] In the present embodiment, the lens 150 includes a plurality of metal columns 153, and the plurality of metal columns 153 are two-dimensionally and periodically arranged in the first metal parallel plate group 133. The metal columns 153 located at the outer periphery of the plurality of metal columns 153 are formed into the arc surface 151 away from one side of the Cassegrain primary reflector 131.

[0054] It should be noted that two-dimensionally and periodically arranged means that the cross sections of the plurality of metal columns 153 are arranged in the same plane in the same manner with the same arrangement pitch.

[0055] In the present embodiment, all the metal columns 153 are equilateral hexagonal prisms with the same side length, and only the height of each row is different.

[0056] In some other embodiments of the present application, the lens 150 can also be a uniform dielectric plate, for example, a section of resin structure with the same equivalent dielectric constant is filled in the first metal parallel plate.

[0057] The application adjusts the outgoing rays through the arc surface 151 to make them more parallel, i.e. reduces the error of the nonlinear phase distribution on the aperture surface, and achieves the goal of improving the radiation performance of the wide-angle scanning beam. Then, the wide-angle scanning within a wide band is realized. The two-dimensional equal-period arrangement of the plurality of metal columns 153 can more easily form a suitable dielectric constant, realize equal-period arrangement, and better realize the geometric parameters of the conic curve.

[0058] In the embodiment, the plurality of metal columns 153 and one parallel plate in the first metal parallel plate group 133 are integrally formed. This facilitates the manufacturing, processing and assembly of the lens 150.

[0059] In the embodiment, the arc surface 151 is convex to the side away from the Cassegrain main reflecting surface 131. The sweep line of the arc surface 151 is a conic curve, and the sweep line of the Cassegrain main reflecting surface 131 is a parabola.

[0060] In the embodiment, the side of the lens 150 close to the Cassegrain main reflecting surface 131 is a straight surface 155, i.e. the row of metal columns 153 close to the Cassegrain main reflecting surface 131 are arranged in a straight line. The width is equal to the radiation aperture.

[0061] In the embodiment, the sweep line of the arc surface 151 satisfies the following formula:

[0062]

[0063] l3 represents the eccentricity of the conic curve, p represents the focal length of the conic curve, z represents the longitudinal coordinate in the coordinate system with the vertex of the sweep line of the Cassegrain main reflecting surface 131 as the coordinate origin, and y represents the transverse coordinate in the coordinate system with the vertex of the sweep line of the Cassegrain main reflecting surface 131 as the coordinate origin. The coordinate axis of the transverse coordinate is the tangent line of the Cassegrain main reflecting surface 131 passing through the vertex, and the coordinate axis of the longitudinal coordinate is the symmetry axis of the sweep line of the Cassegrain main reflecting surface 131.

[0064] The z value on both sides of the fixed conic curve is unchanged. The smaller the eccentricity, the smaller the focal length, and the larger l3, which represents the greater the curvature of the conic curve, and the greater the deflection angle of the incident rays after refraction. By designing a suitable dielectric constant and the geometric parameters of the conic curve, the outgoing rays can be adjusted to be more parallel, i.e. the error of the nonlinear phase distribution on the aperture surface is reduced, and the goal of improving the radiation performance of the wide-angle scanning beam is achieved. Then, the wide-angle scanning within a wide band is realized.

[0065] In the embodiment, the height of the lens 150 decreases from the center of the lens 150 to the side close to the Cassegrain primary reflector 131 and to the side away from the Cassegrain primary reflector 131, respectively. Thus, the lens 150 can be matched with the air-filled first metal parallel plate group 133.

[0066] In the embodiment, the height of each row of the plurality of metal columns 153 is the same, the height of each column gradually decreases from the middle to the two sides, and the height of the metal column 153 in the middle is the highest. Of course, in other embodiments of the present application, the height of the filled resin material can also gradually decrease from the middle to the two sides.

[0067] In the embodiment, the feed source 110 includes a board end connector 111, a waveguide array short circuit end 113, a feed network 115, and a waveguide array 117 arranged in sequence, and the board end connector 111 is used for antenna signal input. The beamformer also has a second metal parallel plate group 135, a third metal parallel plate group 137, and a Cassegrain secondary reflector 139. The first metal parallel plate group 133, the second metal parallel plate group 135, and the third metal parallel plate group 137 are arranged in pairs. The Cassegrain secondary reflector 139 is formed at one end of the second metal parallel plate group 135 and the third metal parallel plate group 137. The Cassegrain primary reflector 131 is formed between the second metal parallel plate group 135 and the first metal parallel plate group 133. The Cassegrain secondary reflector 139 and the Cassegrain primary reflector 131 are oppositely arranged. The third metal parallel plate group 137 is arranged in the electromagnetic wave radiation path of the waveguide array 117. Electromagnetic waves radiated by the waveguide array 117 enter the third metal parallel plate group 137, are reflected by the Cassegrain secondary reflector 139 to the second metal parallel plate group 135, and are reflected by the Cassegrain primary reflector 131 to the first metal parallel plate group 133. The spacing of the third metal parallel plate group decreases from the middle to the two sides of the waveguide array 117 and the Cassegrain secondary reflector, respectively.

[0068] In the embodiment, the spacing of the third metal parallel plate group 137 decreases from the middle to the two sides of the waveguide array 117 and the Cassegrain secondary reflector, respectively, so that the impedance can be matched.

[0069] In the embodiment, the sweep line of the Cassegrain primary reflector 131 is a parabola, and the function thereof satisfies the following formula:

[0070] y 2 =4f m z;

[0071] wherein f mFor parabolic focal length, the greater the focal length, the smaller the curvature of the primary reflecting surface; y represents the longitudinal coordinate of the coordinate system with the vertex of the Cassegrain primary reflecting surface 131 as the coordinate origin, and z represents the transverse coordinate of the coordinate system with the vertex of the Cassegrain primary reflecting surface 131 as the coordinate origin, wherein the coordinate axis of the transverse coordinate is the tangent line of the Cassegrain primary reflecting surface 131 passing through the vertex, and the coordinate axis of the longitudinal coordinate is the symmetry axis of the Cassegrain primary reflecting surface 131.

[0072] The sweep line of the Cassegrain secondary reflecting surface 139 is a hyperbola, which satisfies the following formula:

[0073]

[0074] Wherein, f s is the focal length of the hyperbola, and e is the eccentricity of the hyperbola. According to the working principle of the Cassegrain reflecting surface, one side of the hyperbola coincides with the focal point of the primary reflecting surface, and the other side of the hyperbola is placed with the feed source 110. The cylindrical wave is emitted through the feed source 110 located at the focal point position, and after being reflected by the Cassegrain secondary reflecting surface 139 and the Cassegrain primary reflecting surface 131, it is converted into a plane wave at the aperture of the Cassegrain primary reflecting surface 131, and then a high-gain narrow beam is formed. In addition, when the feed source 110 is laterally offset from the focal point position by a certain distance, the lateral defocusing effect will cause the beam pointing angle to shift. When the Cassegrain double-reflection surface structure is fixed, the greater the lateral defocusing distance of the feed source 110, the greater the scanning angle of the formed beam. However, at the same time, due to the difference between the phase distribution of the field on the aperture and the ideal linear phase distribution, the radiation performance of the large-angle scanning beam deteriorates, which is manifested as an increase in the sidelobe level and a decrease in the gain.

[0075] In the embodiment, the third metal parallel plate group 137 and the second metal parallel plate group 135 share one metal parallel plate, and the second metal parallel plate and the third metal parallel plate share one metal parallel plate.

[0076] Please refer to Figure 1 , Figure 2 and Figure 12 In the embodiment, the multi-beam planar antenna 100 further comprises a radiation structure 170, which is arranged on the side from which the metal parallel plate group radiates the beam, and the radiation structure is arranged at an angle with the first metal parallel plate group. The radiation structure 170 is a group of metal plates that open up, and the opening of the group of metal plates increases in the direction away from the first metal parallel plate group 133.

[0077] It should be noted that the radiation structure is arranged at an angle with the first metal parallel plate group in order to change the direction of the beam, so that the antenna can realize the required beam coverage according to the actual application scene. For example, two identical antennas are placed in a back-to-back form, and the metal plate group connected to the radiation structure is inclined downward, so that a wide range and dense electric wave coverage in the azimuth plane can be realized.

[0078] In the embodiment, two adjacent waveguides in the waveguide array are fed in phase and with equal amplitude to excite the Cassegrain beam former 130 to form a scanning beam, and the same waveguide is shared by two adjacent beams, and the waveguide array 117 is controlled by two groups of switch circuits. The waveguide array 117 is integrated into the circuit board by a microstrip-to-ridge waveguide adapter structure, and then controlled by the switch circuit to realize the conversion of two feed ports into an input port corresponding to a radiation beam. The waveguide array 117 is located in the same plane, and the feed sources 110 at different transverse defocusing positions are used to form scanning beams with different directions in the horizontal plane.

[0079] In some embodiments of the present application, a multi-beam planar line structure can also be used to realize end-on radiation, and two antennas with the same feed source 110, Cassegrain beam former 130 and lens 150 can also be used, the metal parallel plate connected to the radiation structure 170 is bent at the same angle, and the two antennas are placed in a back-to-back form and point in opposite directions.

[0080] Please refer to Figure 5 , Figure 6 and Figure 7 , it can be seen from the simulation and test results that the simulation results and test results are highly consistent in the entire working frequency band, |Smm| (m = 1-11) is less than -9dB, and the transmission coefficient test values between the two symmetrically distributed ports are less than -20dB, and the transmission coefficient between the two asymmetrically distributed ports is smaller, thus proving that the antenna has high port isolation. The antenna has a working bandwidth of about 35%, works in the Ka frequency band, and has a wideband characteristic.

[0081] Please refer to Figure 8 , Figure 9 and Figure 10 , where the dashed line is the simulation result and the solid line is the test result. Due to the symmetry of the structure, only the test patterns of 11 independent radiation beams are given here. It can be seen that the test results are consistent with the simulation results, the scanning angle is ±60°, the cross beam average is higher than -3dB, the sidelobe level test result is less than -9dB, and the cross polarization level value is less than -20dB. The test results verify that the antenna has good wide-angle scanning performance and stable performance in the entire working frequency band.

[0082] Please refer to Figure 11 and Figure 12The gain test result is consistent with the simulation result, the gain test result is up to 18.1dBi, the gain change of each port is within-3dB, and the radiation performance is stable.

[0083] Please refer to Figure 13 As shown in the figure, the wide-angle scanning multi-beam planar antenna 100 based on the application can realize a large range of azimuth plane wave coverage by using a single antenna structure, and can be used in indoor wireless communication and other application scenarios.

[0084] Please refer to Figure 14 The application provides a double-antenna structure wave coverage scheme based on the wide-angle scanning multi-beam planar antenna 100. The metal parallel plate connected with the radiation structure 170 is bent by a certain angle to change the beam pointing direction and coverage range of the antenna in the E plane.

[0085] In summary, the working principle and beneficial effects of the multi-beam planar antenna 100 provided by the application include:

[0086] The lens 150 can improve the phase in the aperture field, so that the nonlinear phase distribution tends to be linear, thereby reducing the sidelobe level and improving the gain and aperture efficiency to realize good beam radiation performance in a wide-angle scanning range.

[0087] The above is only a specific embodiment of the application, but the protection scope of the application is not limited to this. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A multi-beam planar antenna, characterized by, The application relates to a multi-beam planar antenna. The multi-beam planar antenna comprises a feed source for radiating electromagnetic waves, a Cassegrain beam former arranged in the radiation direction of the electromagnetic waves of the feed source, the Cassegrain beam former having a Cassegrain primary reflector and a first metal parallel plate group arranged in the electromagnetic wave radiation direction of the Cassegrain primary reflector, and a lens arranged in the first metal parallel plate group, the lens being arc-shaped on the side away from the Cassegrain primary reflector and used for correcting the phase of the aperture field of the multi-beam planar antenna to make the aperture field phase distribution tend to linear distribution. The lens comprises a plurality of metal columns which are two-dimensionally and equicyclically distributed, and the metal columns located at the outer periphery of the lens form the arc-shaped surface on the side away from the Cassegrain primary reflector. The arc-shaped surface is convex on the side away from the Cassegrain primary reflector, the sweep line of the arc-shaped surface is a conic curve, and the sweep line of the arc-shaped surface satisfies the following formula: The lens is a homogeneous medium plate. The plurality of metal columns are integrally formed with one parallel plate in the first metal parallel plate group. L3 is the distance from the vertex of the conic to the vertex of the paraboloid, e l represents the eccentricity of the conic, p represents the focal distance of the conic, z represents the longitudinal coordinate in a coordinate system with the vertex of the sweep line of the Cassegrain primary reflector as the coordinate origin, and y represents the lateral coordinate in the coordinate system with the vertex of the sweep line of the Cassegrain primary reflector as the coordinate origin, wherein the coordinate axis of the lateral coordinate is the tangent line of the Cassegrain primary reflector passing through the vertex, and the coordinate axis of the longitudinal coordinate is the axis of symmetry of the sweep line of the Cassegrain primary reflector.

2. The multi-beam planar antenna according to claim 1, characterized in that, The arc-shaped surface is convex on the side away from the Cassegrain primary reflector, and the sweep line of the Cassegrain primary reflector is a parabola.

3. The multi-beam planar antenna according to claim 1, characterized in that, The lens is straight on the side close to the Cassegrain primary reflector.

4. The multi-beam planar antenna according to any one of claims 1-3, characterized in that, The height of the lens decreases from the center of the lens to the side close to the Cassegrain primary reflector and to the side away from the Cassegrain primary reflector.

5. The multi-beam planar antenna according to any one of claims 1-3, characterized in that, The feed source comprises a plate end connector, a waveguide array short circuit end, a feed network and a waveguide array which are sequentially arranged, and the plate end connector is used for antenna signal input.

6. The multi-beam planar antenna according to any one of claims 1-3, characterized in that, The beam former further comprises a second metal parallel plate group, a third metal parallel plate group and a Cassegrain secondary reflector, the first metal parallel plate group, the second metal parallel plate group and the third metal parallel plate group are arranged in parallel two by two, the Cassegrain secondary reflector is formed at one end of the second metal parallel plate group and the third metal parallel plate group, the Cassegrain primary reflector is formed between the second metal parallel plate group and the first metal parallel plate group, the Cassegrain secondary reflector and the Cassegrain primary reflector are arranged oppositely, and the third metal parallel plate group is arranged in the electromagnetic wave radiation path of the waveguide array.

7. The multi-beam planar antenna according to any one of claims 1-3, characterized in that, The distance between the third metal parallel plate groups decreases from the middle to the two sides of the waveguide array and the Cassegrain secondary reflector. The multi-beam planar antenna further comprises a radiation structure arranged on the side of the first metal parallel plate group from which the beam is radiated, and the radiation structure is arranged at an angle with the first metal parallel plate group, the radiation structure is a metal plate group which is opened, and the opening of the metal plate group which is opened increases away from the first metal parallel plate group. ​ 8. The multi-beam planar antenna according to any one of claims 1-3, characterized in that, ​

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