Broadband high-gain two-dimensional digital holographic antenna, design method thereof and communication equipment

Abstract

The invention discloses a broadband high-gain two-dimensional digital holographic antenna and a design method thereof, and a communication device, the antenna comprises a holographic antenna radiation layer, a dielectric layer, a metal floor and a feed structure, the dielectric layer is arranged between the holographic antenna radiation layer and the metal floor, the feed structure is connected with the bottom layer of the metal floor, and the metal floor is arranged on the dielectric layer. A metal wall is arranged on the periphery of the top layer of the metal floor, the metal wall is connected with the holographic antenna radiation layer, the holographic antenna radiation layer comprises an antenna radiation array and a multilayer dielectric substrate, a radiation unit of the antenna radiation array is a slot radiation unit, and the slot radiation unit is arranged on the multilayer dielectric substrate. The antenna provided by the invention has the characteristics of wide frequency band, high gain, wide scanning and reconfigurability.

Description

Technical Field

[0001] The present invention relates to a broadband high-gain two-dimensional digital holographic antenna, an antenna design method, and a communication device, belonging to the field of wireless communication technology. Background Art

[0002] As a millimeter-wave antenna, a holographic antenna has the characteristics of simple structure, low profile, light weight, and low energy loss, which can solve the problems of high cost and complex structure encountered by phased arrays in civil applications, and thus has attracted the attention of a large number of researchers. Traditional holographic antennas are mainly realized by artificially modulated metamaterials, using impedance surfaces to record interference wave patterns, and using feed sources such as monopole or horn antennas to excite the interference wave patterns, thereby realizing beamforming in the expected direction.

[0003] For a holographic antenna realized based on artificially modulated metamaterials, its beam pointing cannot be adjusted by an electronic control method. To achieve beam reconfiguration, introducing radio frequency switches into the holographic antenna is an effective solution. By using radio frequency switches to change the radiation state of the array radiation units, and then changing the recorded interference wave patterns, beam reconfiguration can be finally realized. However, radio frequency switches such as PIN diodes and varactor diodes are lossy elements to the antenna, which will greatly affect the radiation performance of the antenna radiation units, thereby deteriorating the indicators such as the gain, bandwidth, and efficiency of the holographic antenna. Existing beam-reconfigurable holographic antennas lack the optimization of the antenna radiation units after loading radio frequency switches, resulting in narrow bandwidth and low gain of the beam-reconfigurable holographic antenna, which affects the practical application of the reconfigurable holographic antenna. Summary of the Invention

[0004] The first object of the present invention is to overcome the disadvantages and deficiencies of the prior art, and provide a broadband high-gain two-dimensional digital holographic antenna, which has the characteristics of wide frequency band, high gain, wide scan, and reconfigurability.

[0005] The second object of the present invention is to provide a design method for the above-mentioned broadband high-gain two-dimensional digital holographic antenna.

[0006] The third object of the present invention is to provide a wireless communication device including the above-mentioned broadband high-gain two-dimensional digital holographic antenna.

[0007] The first object of the present invention can be achieved by adopting the following technical solutions:

[0008] A broadband high-gain two-dimensional digital holographic antenna, comprising a holographic antenna radiation layer, a dielectric layer, a metal floor and a feeding structure. The dielectric layer is disposed between the holographic antenna radiation layer and the metal floor. The feeding structure is connected to the bottom layer of the metal floor. A metal wall is provided around the top layer of the metal floor, and the metal wall is connected to the holographic antenna radiation layer. The holographic antenna radiation layer includes an antenna radiation array and a multi-layer dielectric substrate. The radiation units of the antenna radiation array are slot radiation units, and the slot radiation units are arranged on the multi-layer dielectric substrate.

[0009] Further, the multi-layer dielectric substrate includes a first dielectric substrate, a second dielectric substrate, a third dielectric substrate and a fourth dielectric substrate arranged in sequence. The slot radiation unit includes a switch component, a bias circuit, a slot, a grounding metal hole and an avoidance metal hole. The bias circuit includes a feeder and a choke stub. The avoidance metal hole includes a metal connection hole and an avoidance circular groove;

[0010] The grounding metal hole and the metal connection hole penetrate through the first dielectric substrate, the second dielectric substrate and the third dielectric substrate; the switch component and the feeder are disposed on the first dielectric substrate, and the switch component is connected to the feeder; the choke stub is disposed on the third dielectric substrate; a metal layer is arranged on the fourth dielectric substrate as a common ground, and the common ground is connected to the grounding metal hole. The slot and the avoidance circular groove are etched on the common ground; the feeder is connected to the choke stub through the metal connection hole, and the center of the avoidance circular groove is set at the center of the metal connection hole; depth control grooves corresponding to the position of the slot are provided on the second dielectric substrate, the third dielectric substrate and the fourth dielectric substrate.

[0011] Further, the slot includes a first rectangular slot and a second rectangular slot. The length of the first rectangular slot is greater than the length of the second rectangular slot. One short side of the second rectangular slot is connected to the center of the first rectangular slot to form a T-shaped slot. The two short sides of the first rectangular slot and the other short side of the second rectangular slot are in a semi-circular arc shape.

[0012] Further, the switch component includes a radio frequency switch and a switch pad. The switch pad includes a positive switch pad and a negative switch pad. The positive electrode of the radio frequency switch is connected to the positive switch pad, and the negative electrode of the radio frequency switch is connected to the negative switch pad. The position of the negative switch pad corresponds to the position of the first rectangular slot, and the position of the positive switch pad corresponds to the position of the second rectangular slot. The positive switch pad is connected to the starting end of the feeder, and the ending end of the feeder is connected to the metal connection hole.

[0013] Further, the feeder extends from the connection with the positive switch pad to the connection with the metal connection hole and is bent to save the unit size.

[0014] Further, the choke stub is a sector stub, and the center of the choke stub is correspondingly connected to the center of the metal connection hole.

[0015] Further, a square protrusion is provided at the center of the bottom layer of the metal floor, and the feeding structure is connected to the square protrusion to feed in radio frequency signals and reduce the weight of the metal floor.

[0016] The second object of the present invention can be achieved by adopting the following technical solutions:

[0017] A design method for the above broadband high-gain two-dimensional digital holographic antenna, which is realized by designing the position and angle of the slot radiation unit;

[0018] When the holographic antenna is a linearly polarized holographic antenna, the method includes: taking the center of the antenna radiation array as the origin, establishing a Cartesian coordinate system by setting the x-axis and y-axis in the transverse and longitudinal directions respectively. The direction perpendicular to the long side of the slot and away from the origin is the normal direction of the long side of the slot, and the direction from the origin to the slot radiation unit is the radial direction, and the x-axis direction is the main polarization direction. First, design the position and angle of the slot radiation unit in the first quadrant of the Cartesian coordinate system. The position of the slot radiation unit in the first quadrant is arranged in a sector or rectangular shape. The angle of the slot radiation unit in the first quadrant is the angle between the normal direction of the long side of the slot and the main polarization direction, which is less than or equal to 45°, and the angle between the normal direction of the long side of the slot and the radial direction is less than or equal to 45° to satisfy the slot excitation radiation while suppressing cross polarization. Then, the slot radiation unit in the second quadrant of the Cartesian coordinate system is the mirror image arrangement of the position and angle of the slot radiation unit in the first quadrant with respect to the y-axis. Then, the slot radiation unit in the third quadrant of the Cartesian coordinate system is the mirror image arrangement of the position and angle of the slot radiation unit in the second quadrant with respect to the x-axis. Finally, the slot radiation unit in the fourth quadrant of the Cartesian coordinate system is the mirror image arrangement of the position and angle of the slot radiation unit in the third quadrant with respect to the y-axis, and the arrangement of the entire antenna radiation array is completed.

[0019] When the holographic antenna is a circularly polarized holographic antenna, the method includes: taking the center of the antenna radiation array as the origin, establishing a Cartesian coordinate system by setting up the x-axis and y-axis in the transverse and longitudinal directions respectively, and the direction perpendicular to the long side of the slot and away from the origin is the normal direction of the long side of the slot; first, design the positions and angles of the slot radiation units in the first quadrant of the Cartesian coordinate system. The positions of the slot radiation units in the first quadrant are arranged in a fan shape or a rectangle, and the angle of the slot radiation units in the first quadrant is that the angle between the normal direction of the long side of the slot and the positive x-axis is 45°, so as to achieve circular polarization while satisfying slot excitation radiation; then, the slot radiation units in the second quadrant of the Cartesian coordinate system are mirror arrangements of the positions and angles of the slot radiation units in the first quadrant with respect to the y-axis; then, the slot radiation units in the third quadrant of the Cartesian coordinate system are mirror arrangements of the positions and angles of the slot radiation units in the second quadrant with respect to the x-axis; finally, the slot radiation units in the fourth quadrant of the Cartesian coordinate system are mirror arrangements of the positions and angles of the slot radiation units in the third quadrant with respect to the y-axis, and the arrangement of the entire antenna radiation array is completed.

[0020] The second object of the present invention can also be achieved by adopting the following technical solutions:

[0021] A design method of the above-mentioned broadband high-gain two-dimensional digital holographic antenna, the method is realized by quantifying the beam scanning of the slot radiation intensity;

[0022] When the holographic antenna is a linearly polarized holographic antenna, the method includes: taking the center of the antenna radiation array as the origin, establishing a Cartesian coordinate system by setting up the x-axis and y-axis in the transverse and longitudinal directions respectively, and using the position of each slot radiation unit and the desired beam pointing direction, normalizing the radiation intensity of each slot radiation unit to obtain the normalized radiation intensity of each slot radiation unit; performing a threshold decision on the normalized radiation intensity of each slot radiation unit. If the normalized radiation intensity of the slot radiation unit is greater than the set threshold, it is determined that the radiation intensity of the slot radiation unit is 1. If the normalized radiation intensity of the slot radiation unit is less than or equal to the set threshold, it is determined that the radiation intensity of the slot radiation unit is 0.

[0023] When the holographic antenna is a circularly polarized holographic antenna, the method includes: taking the center of the antenna radiation array as the origin, establishing a Cartesian coordinate system by setting up the x-axis and y-axis in the transverse and longitudinal directions respectively, and using the position of each slot radiation unit and the desired beam pointing direction, normalizing the radiation intensity of each slot radiation unit to obtain the normalized radiation intensity of each slot radiation unit for right-handed circular polarization and the normalized radiation intensity of each slot radiation unit for left-handed circular polarization; performing a threshold decision on the normalized radiation intensity of each slot radiation unit. If the normalized radiation intensity of the slot radiation unit is greater than the set threshold, it is determined that the radiation intensity of the slot radiation unit is 1. If the normalized radiation intensity of the slot radiation unit is less than or equal to the set threshold, it is determined that the radiation intensity of the slot radiation unit is 0.

[0024] The third objective of the present invention can be achieved by adopting the following technical solutions:

[0025] A communication device includes the above-mentioned broadband high-gain two-dimensional digital holographic antenna.

[0026] The present invention has the following beneficial effects compared with the prior art:

[0027] The antenna of the present invention has a holographic antenna radiation layer, a dielectric layer, a metal floor, and a feeding structure. The dielectric layer is arranged between the holographic antenna radiation layer and the metal floor. The feeding structure is connected to the bottom layer of the metal floor. A metal wall connected to the holographic antenna radiation layer is arranged around the top layer of the metal floor. The whole antenna forms a radial line waveguide structure. The dielectric layer serves as the propagation medium of the radial line waveguide structure and can play a role in reducing losses for air. The holographic antenna radiation layer has an antenna radiation array, and the radiation units of the antenna radiation array are slot radiation units. By reasonably designing the positions and angles of the slot radiation units, linear polarization and circular polarization can be achieved, and linear polarization and circular polarization can also be achieved through beam scanning of quantifying the slot radiation intensity. Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0029] Figure 1 It is an exploded view of the broadband high-gain two-dimensional digital holographic antenna according to Embodiment 1 of the present invention.

[0030] Figure 2 It is a top view of the broadband high-gain two-dimensional digital holographic antenna according to Embodiment 1 of the present invention.

[0031] Figure 3 It is a side view of the broadband high-gain two-dimensional digital holographic antenna according to Embodiment 1 of the present invention.

[0032] Figure 4 It is an exploded view of each layer of dielectric substrate according to Embodiment 1 of the present invention.

[0033] Figure 5 It is a top view of the slot radiation unit according to Embodiment 1 of the present invention.

[0034] Figure 6 It is a structural schematic diagram of the first dielectric substrate according to Embodiment 1 of the present invention.

[0035] Figure 7Schematic diagram of the second dielectric substrate of Embodiment 1 of the present invention.

[0036] Figure 8 Schematic diagram of the third dielectric substrate of Embodiment 1 of the present invention.

[0037] Figure 9 Schematic diagram of the fourth dielectric substrate of Embodiment 1 of the present invention.

[0038] Figure 10 Schematic diagram of the electric field of different angle designs of the slot radiation unit in the linear polarization holographic antenna of Embodiment 1 of the present invention.

[0039] Figure 11 Schematic diagram of the electric field of the slot radiation unit design in the circular polarization holographic antenna of Embodiment 2 of the present invention.

[0040] Figure 12 Gain curve of the linear polarization holographic antenna of Embodiment 3 of the present invention in the frequency band of 24.5 - 27.5 GHz when the beam pointing Theta = 0°.

[0041] Figure 13 Radiation efficiency diagram of the linear polarization holographic antenna of Embodiment 3 of the present invention in the frequency band of 24.5 - 27.5 GHz when the beam pointing Theta = 0°.

[0042] Figure 14 Gain curve of the linear polarization holographic antenna of Embodiment 4 of the present invention at different scan azimuth angles when the frequency is 26 GHz and Theta = 45°.

[0043] Figure 15 Gain curve of the linear polarization holographic antenna of Embodiment 4 of the present invention at different scan elevation angles when the frequency is 26 GHz and Phi = 0°.

[0044] Wherein, 1 - holographic antenna radiation layer, 2 - dielectric layer, 3 - metal floor, 4 - feeding structure, 5 - metal wall, 6 - antenna radiation array, 601 - bias circuit, 6011 - feeder line, 6012 - choke stub, 602 - slot, 603 - grounding metal hole, 604 - avoidance metal hole, 6041 - metal connection hole, 6042 - avoidance circular groove, 605 - RF switch, 606 - switch pad, 6061 - positive switch pad, 6062 - negative switch pad, 7 - square protrusion, 8 - first dielectric substrate, 9 - second dielectric substrate, 10 - third dielectric substrate, 11 - fourth dielectric substrate, 12 - controlled depth groove, 1201 - first controlled depth groove, 1202 - second controlled depth groove, 1203 - third controlled depth groove. Detailed implementation mode

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are only a part rather than all of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0046] Embodiment 1:

[0047] As Figures 1 to 3 shown, this embodiment provides a broadband high-gain two-dimensional digital holographic antenna, which can be applied to various communication devices. It includes a holographic antenna radiation layer 1, a dielectric layer 2, a metal floor 3, and a feeding structure 4. The dielectric layer 2 is disposed between the holographic antenna radiation layer 1 and the metal floor 3. The feeding structure 4 is connected to the bottom layer of the metal floor 3. A metal wall 5 is provided around the top layer of the metal floor 3. The metal wall 5 encloses a square and is connected to the holographic antenna radiation layer 1. The antenna as a whole forms a radial line waveguide structure. The dielectric layer 2 serves as the waveguide propagation medium of the radial line waveguide and can play a role in reducing losses for air. The holographic antenna radiation layer 1 includes an antenna radiation array 6 and multiple dielectric substrates. The radiation units of the antenna radiation array 6 are slot radiation units, and the slot radiation units are arranged on the multiple dielectric substrates.

[0048] In this embodiment, the antenna radiation array 6 is arranged in a circular pattern. The innermost circle includes eight slot radiation units, and four slot radiation units are incremented in each subsequent circle, with a total of twenty-one circles. A square protrusion 7 is provided at the center of the bottom layer of the metal floor 3. The feeding structure 4 is connected to the square protrusion 7 to feed in the radio frequency signal and reduce the weight of the metal floor. The height H of the square protrusion 7 is related to the matching of the feeding structure 4, and the side length L of the square protrusion 7 is related to the flange size of the feeding structure 4. In this embodiment, H = 8.2 mm and L = 14 mm are selected. The feeding structure 4 is coaxial feeding. The outer core of the coaxial cable is connected to the square protrusion 7, and the inner core of the coaxial cable is connected to the air inside. The distance between the inner core of the coaxial cable and the holographic antenna radiation layer 1 is related to the matching of the feeding structure 4.

[0049] As Figure 4 and Figure 5As shown in the figure, the multi-layer dielectric substrate includes a first dielectric substrate 8, a second dielectric substrate 9, a third dielectric substrate 10, and a fourth dielectric substrate 11 arranged in sequence. The slot radiation unit includes a switch component, a bias circuit 601, a slot 602, a ground via 603, and an avoidance via 604. The bias circuit 601 includes a feeder 6011 and a choke stub 6012. The bias circuit is connected to a controller to control the voltage across the switch component. The controller can be an FPGA (Field-Programmable Gate Array). The avoidance via includes a metal connection hole 6041 and an avoidance circular groove 6042.

[0050] As Figures 4 to 9 As shown in the figure, the ground via 603 and the metal connection hole 6041 penetrate through the first dielectric substrate 8, the second dielectric substrate 9, and the third dielectric substrate 10 to apply a DC voltage to the switch component to control the on and off states of the switch component. The switch component and the feeder 6011 are disposed on the first dielectric substrate 8, and the switch component is connected to the feeder 6011. The choke stub 6012 is disposed on the third dielectric substrate 10. A metal layer is arranged on the fourth dielectric substrate 11 as a common ground, and the common ground is connected to the ground via 603. The slot 602 and the avoidance circular groove 6042 are etched on the common ground. The feeder 6011 is connected to the choke stub 6012 through the metal connection hole 6041. The center of the avoidance circular groove 6042 is set at the center of the metal connection hole 6041 to isolate the electrical performance between the metal connection hole 6041 and the common ground. Depth control grooves 12 corresponding to the position of the slot 602 are provided on the second dielectric substrate 9, the third dielectric substrate 10, and the fourth dielectric substrate 11.

[0051] Furthermore, the slot 602 includes a first rectangular slot and a second rectangular slot. The length of the first rectangular slot is greater than the length of the second rectangular slot. One of the short sides of the second rectangular slot is connected to the center of the first rectangular slot to form a T-shaped slot. It can be seen that the first rectangular slot is a long rectangular slot, that is, a traditional rectangular slot, and the second rectangular slot is a short rectangular slot. By adding a short rectangular slot in the middle normal direction of one of the long sides of the traditional rectangular slot, a T-shaped slot can be formed as a whole. The two short sides of the first rectangular slot and the other short side of the second rectangular slot are in a semi-circular arc shape to facilitate the processing of the depth control groove 7.

[0052] Further, the switch component includes a radio frequency switch 605 and a switch pad 606. The switch pad 606 includes a positive switch pad 6061 and a negative switch pad 6062. The radio frequency switch 605 is a PIN diode or a varactor diode. The positive electrode of the radio frequency switch 605 is connected to the positive switch pad 6061, and the negative electrode of the radio frequency switch 605 is connected to the negative switch pad 6062. The position of the negative switch pad 6062 corresponds to the position of the first rectangular slot, and the position of the positive switch pad 6061 corresponds to the position of the second rectangular slot. The positive switch pad 6061 is connected to the starting end of the feeder 6011, and the ending end of the feeder 6011 is connected to the metal connection hole 6041. Specifically, the feeder 6011 extends from the connection with the positive switch pad 6061 to the connection with the metal connection hole 6041 and is bent to save the unit size. The choke stub 6012 is a fan-shaped stub, and the center of the choke stub 6012 is correspondingly connected to the center of the metal connection hole 6041.

[0053] As Figure 6 shown, the shape of the first dielectric substrate 8 is selected as a square with a side length W = 230 mm. The first dielectric substrate 407 is selected with a material of RO4350B, a dielectric constant of 3.48, a loss tangent of 0.0027, and a thickness of 4 mil. The specific dimensions of the positive switch pad 6061 are LP2 = 0.5 mm and WP2 = 0.4 mm. The feeder 6011 is led out from DL1 = 0.15 mm of the positive switch pad 6061, and the specific dimensions are TL1 = 0.15 mm, TL2 = 0.4 mm, TL3 = 1.15 mm, TL4 = 1.05 mm, and ɑ = 45°. The negative switch pad 6062 is separated from the positive switch pad 6061 by LP3 = 0.3 mm, and its specific dimensions are LP1 = 0.9 mm and WP1 = 0.6 mm. A grounding metal hole 603 is provided at the position of LV1 = 0.75 mm.

[0054] As Figure 7 shown, the shape of the second dielectric substrate 9 is selected as a square with a side length W = 230 mm. The second dielectric substrate 9 is selected with a material of RO4450F, a dielectric constant of 3.52, a loss tangent of 0.0027, and a thickness of 8 mil. The controlled-depth grooves 12 arranged thereon are the first controlled-depth grooves 1201, and the specific dimensions are R1 = 0.4 mm, LS1 = 2.9 mm, LS2 = 0.25 mm, and LV2 = 0.5 mm.

[0055] As Figure 8As shown, the shape of the third dielectric substrate 10 is selected as a square with a side length W = 230 mm. The third dielectric substrate 409 is selected with a material of RO4350B, a dielectric constant of 3.48, a tangent of the loss angle of 0.0027, and a thickness of 4 mil. The arranged controlled-depth grooves 12 thereon are the second controlled-depth grooves 1202, with specific dimensions of R1 = 0.4 mm, LS1 = 2.9 mm, LS2 = 0.25 mm, and LV2 = 0.5 mm, corresponding one by one to the positions of the first controlled-depth grooves 1201; the specific dimensions of the choke stub 6012 are TL5 = 1.75 mm and β = 75°.

[0056] As Figure 9 As shown, the shape of the fourth dielectric substrate 11 is selected as a square with a side length W = 230 mm. The materials of the fourth dielectric substrate 11 from top to bottom are PP which is RO4450F, with a dielectric constant of 3.52, a tangent of the loss angle of 0.0027, and a thickness of 8 mil; Core is RO4003C, with a dielectric constant of 3.55, a tangent of the loss angle of 0.0027, and a thickness of 20 mil. The arranged controlled-depth grooves 12 thereon are the third controlled-depth grooves 1203, with specific dimensions of R1 = 0.4 mm, LS1 = 2.9 mm, LS2 = 0.25 mm, and LV2 = 0.5 mm, corresponding one by one to the positions of the first controlled-depth grooves 1201, the second controlled-depth grooves 1202, and the slot 602; the side of the avoidance circular groove 6042 is 0.2 mm away from the side surface of the metal connection hole 6041.

[0057] In this embodiment, a linearly polarized holographic antenna is realized by designing the positions and angles of the slot radiation units. The specific process is as follows: Taking the center of the antenna radiation array as the origin, the x-axis and y-axis are respectively established in the horizontal and vertical directions to establish a Cartesian coordinate system. The direction perpendicular to the long side of the slot and away from the origin is the normal direction of the long side of the slot, and the direction from the origin to the slot radiation unit is the radial direction, and the x-axis direction is the main polarization direction; First, design the positions and angles of the slot radiation units in the first quadrant of the Cartesian coordinate system. The positions of the slot radiation units in the first quadrant can be arranged in a fan shape or a rectangle. The angle of the slot radiation units in the first quadrant is the angle between the normal direction of the long side of the slot and the main polarization direction, which is less than or equal to 45°, and the angle between the normal direction of the long side of the slot and the radial direction is less than or equal to 45°, so as to suppress the cross polarization while satisfying the slot excitation radiation; Then, the slot radiation units in the second quadrant of the Cartesian coordinate system are the mirror image arrangements of the positions and angles of the slot radiation units in the first quadrant with respect to the y-axis; Then, the slot radiation units in the third quadrant of the Cartesian coordinate system are the mirror image arrangements of the positions and angles of the slot radiation units in the second quadrant with respect to the x-axis; Finally, the slot radiation units in the fourth quadrant of the Cartesian coordinate system are the mirror image arrangements of the positions and angles of the slot radiation units in the third quadrant with respect to the y-axis, and the arrangement of the entire antenna radiation array is completed.

[0058] The angle selection of the slot radiation unit of the linear polarization holographic antenna in this embodiment is as follows:

[0059] As Figure 10 shown, it is the electric field schematic diagram of different angle designs of the slot radiation unit in the linear polarization holographic antenna. The main mode propagated by the radial waveguide structure is TM 00 , and the mode diagram of TM 00 is distributed in a ring shape, and the propagation direction is the radial direction. According to the electromagnetic field theory, the surface current of the radial waveguide is determined by the tangential component of the magnetic field on the waveguide wall surface:

[0060]

[0061] The direction of the surface current on the upper wall of the radial waveguide structure with the main mode of TM 00 is the radial direction. The slot on the waveguide wall will cut off the current on the wall. In order to ensure the current continuity, a displacement current will be generated on the slot. This displacement current exists in the form of the electric field on both sides of the slot. Since there is a magnetic field component parallel to the slot in the waveguide, the electric field and the magnetic field form a Poynting vector pointing outward on the waveguide, so that the electromagnetic wave radiates outward through the radiation slot; at the same time, the smaller the angle between the current direction and the normal direction of the long side of the slot, the easier it is to generate the displacement current, and the stronger the radiation power of the slot. Figure 10 In , the angle between the normal direction of the long side of slot a and the current direction is 0°, and the radiation power of the slot is the largest. The angle between the normal direction of the long side of slot d and the current direction is 90°, and the radiation power of the slot is almost 0; on the other hand, let the main polarization direction be the x-axis direction. Although the radiation power of slot c is the largest, the polarization is cross polarization and has no contribution to the main polarization. In order to suppress the cross polarization, the angle between the polarization direction of the slot and the main polarization should be as small as possible; in summary, the slot angle is selected such that the angle between the normal direction of the long side of the slot and the main polarization direction is less than or equal to 45° and the angle between the normal direction of the long side of the slot and the radial direction is less than or equal to 45°. Figure 10 Slots a and b in meet the above conditions.

[0062] Embodiment 2:

[0063] In this embodiment, a circularly polarized holographic antenna is realized by designing the position and angle of the slot radiation element. The specific process is as follows: Taking the center of the antenna radiation array as the origin, the x-axis and y-axis are respectively established in the transverse and longitudinal directions to establish a Cartesian coordinate system. The direction perpendicular to the long side of the slot away from the origin is the normal direction of the long side of the slot. First, design the position and angle of the slot radiation element in the first quadrant of the Cartesian coordinate system. The position of the slot radiation element in the first quadrant can be arranged in a fan shape or a rectangle. The angle of the slot radiation element in the first quadrant is the angle between the normal direction of the long side of the slot and the positive x-axis is 45°, so that the electric field vectors in the x-axis direction and the y-axis direction differ by 90°, realizing circular polarization while satisfying slot excitation radiation. Then, the slot radiation element in the second quadrant of the Cartesian coordinate system is the mirror image arrangement of the position and angle of the slot radiation element in the first quadrant with respect to the y-axis. Then, the slot radiation element in the third quadrant of the Cartesian coordinate system is the mirror image arrangement of the position and angle of the slot radiation element in the second quadrant with respect to the x-axis. Finally, the slot radiation element in the fourth quadrant of the Cartesian coordinate system is the mirror image arrangement of the position and angle of the slot radiation element in the third quadrant with respect to the y-axis, and the arrangement of the entire antenna radiation array is completed.

[0064] The angle selection of the slot radiation element of the circularly polarized holographic antenna in this embodiment is as follows:

[0065] As Figure 11 shown, it is the electric field schematic diagram designed for the slot radiation element in the circularly polarized holographic antenna. The initial phases 0°, 90°, 180°, and 270° are respectively introduced into the algorithms of the first quadrant to the fourth quadrant. The combined electric field direction of the slots in the first quadrant and the third quadrant is the E1 electric field direction and the initial phase is 0°. The combined electric field direction of the slots in the second quadrant and the fourth quadrant is the E4 electric field direction and the initial phase is 90°. The E1 electric field direction and the E4 electric field direction differ by 90°. Therefore, the combined electric field phase of the E1 electric field direction lags behind the combined electric field phase of the E4 electric field direction by 90°, and the combined electric field amplitude of the E1 electric field direction is equal to the combined electric field amplitude of the E4 electric field direction, which is left-handed circular polarization. Similarly, by introducing the initial phases 0°, 270°, 180°, and 90° into the algorithms of the first quadrant to the fourth quadrant respectively, right-handed circular polarization can be realized.

[0066] Embodiment 3:

[0067] This embodiment provides a linearly polarized holographic antenna. The antenna radiation array 6 is circularly arranged with 21 circles, as Figure 12 and Figure 13As shown, it is the gain curve and radiation efficiency curve of the linear polarization holographic antenna within the frequency band of 24.5 - 27.5 GHz when the beam direction Theta = 0°. The maximum gain is 22.37 dBi, the minimum gain is 18.67 dBi, and the radiation efficiency is greater than 70%. It can be seen that the holographic antenna in this embodiment has the characteristics of wideband and high gain. Since the radio frequency switch 605 is introduced into the slot radiation unit, the quality factor of the slot radiation unit is improved, and the bandwidth and quality factor of the slot radiation unit are negatively correlated. As a result, the bandwidth of the holographic antenna is reduced after the introduction of the radio frequency switch 605. After the slot 603 is designed as a T shape, the size of the positive electrode switch pad 6061 is smaller than that of the short rectangular slot, and each side of the positive electrode switch pad 6061 is separated from each side of the short rectangular slot by a certain distance. And a controlled-depth groove 12 is used to remove part of the medium between the pad and the slot, so as to weaken the electrical coupling of the radio frequency switch 605 to the slot radiation unit, and then reduce the influence of the radio frequency switch 605 on the quality factor of the slot radiation unit and expand the bandwidth of the holographic antenna.

[0068] Embodiment 4:

[0069] This embodiment provides a linear polarization holographic antenna, and its antenna radiation array 6 selects a circular arrangement with 21 turns, as Figure 14 shown, it is the gain curve of the linear polarization holographic antenna at different scanning azimuth angles when the frequency is 26 GHz and Theta = 45°. The beam scans from 0° to 90°, the maximum beam gain is 18.92 dBi, the maximum gain drops by 4.08 dBi, and the 3dB beam width is less than 10°. As Figure 15 shown, it is the gain curve of the linear polarization holographic antenna at different scanning elevation angles when the frequency is 26 GHz and Phi = 0°. The beam scans from 0° to 60°, the maximum beam gain is 20.51 dBi, the maximum gain drops by 1.88 dBi, the 3dB beam width is less than 10°, and the beam pointing deviation is ±3°. It can be seen that the holographic antenna in this embodiment has the characteristics of narrow beam, wide scan, and good beam pointing accuracy.

[0070] The linear polarization holographic antenna in this embodiment is realized by quantifying the beam scanning of the slot radiation intensity. It uses the holographic principle to judge the state of the radio frequency switch on each slot radiation unit. Taking the center of the antenna radiation array as the origin, the x-axis and y-axis are respectively established in the horizontal and vertical directions to establish a Cartesian coordinate system. Using the position of each slot radiation unit and the desired beam direction, the radiation intensity of each slot radiation unit is normalized to obtain the normalized radiation intensity of each slot radiation unit, as shown in the following formula:

[0071]

[0072] where, is the wave number in free space, and the vector direction is the desired beam direction. is the waveguide beam in the waveguide cavity, and the vector direction is the radial direction from the origin to the slot unit. is the radius vector from the origin to the slot unit, and the vector direction is the radial direction from the origin to the slot unit. A is the normalized radiation intensity of each slot unit.

[0073] Perform threshold judgment on the normalized radiation intensity of each slot radiation unit. If the normalized radiation intensity of the slot radiation unit is greater than the set threshold, judge that the radiation intensity of the slot radiation unit is 1. If the normalized radiation intensity of the slot radiation unit is less than or equal to the set threshold, judge that the radiation intensity of the slot radiation unit is 0.

[0074] The threshold selected in this embodiment is 0.5, and the corresponding angle range is from -60° to 60°. That is, the radiation intensity T of the slot unit is:

[0075]

[0076] The normalized radiation intensity threshold judgment of each slot unit is 1 or 0. That is, when the radiation intensity of the slot radiation unit is 1, it means that the RF switch is off. When the radiation intensity of the slot radiation unit is 0, it means that the RF switch is on.

[0077] Embodiment 5:

[0078] This embodiment provides a circularly polarized holographic antenna, which is realized by beam scanning of quantifying the radiation intensity of the slots. It uses the holographic principle to judge the state of the RF switch on each slot radiation unit. Taking the center of the antenna radiation array as the origin, the x-axis and y-axis are respectively established in the transverse direction and the longitudinal direction to establish a Cartesian coordinate system. Using the position of each slot radiation unit and the desired beam direction, the radiation intensity of each slot radiation unit is normalized to obtain the normalized radiation intensity of each slot radiation unit of right-handed circular polarization and the normalized radiation intensity of each slot radiation unit of left-handed circular polarization, as follows:

[0079]

[0080] Among them, is the wave number in free space, and the vector direction is the desired beam direction. is the waveguide beam in the waveguide cavity, and the vector direction is the radial direction from the origin to the slot unit. is the radius vector from the origin to the slot unit, and the vector direction is the radial direction from the origin to the slot unit. A R is the normalized radiation intensity of each slot radiation unit of right-handed circular polarization, A L is the normalized radiation intensity of each slot radiation unit of left-handed circular polarization.

[0081] Perform threshold judgment on the normalized radiation intensity of each slot radiation unit. If the normalized radiation intensity of the slot radiation unit is greater than the set threshold, judge that the radiation intensity of the slot radiation unit is 1. If the normalized radiation intensity of the slot radiation unit is less than or equal to the set threshold, judge that the radiation intensity of the slot radiation unit is 0.

[0082] In summary, the antenna of the present invention has a holographic antenna radiation layer, a dielectric layer, a metal floor, and a feeding structure. The dielectric layer is arranged between the holographic antenna radiation layer and the metal floor. The feeding structure is connected to the bottom layer of the metal floor. A metal wall connected to the holographic antenna radiation layer is arranged around the top layer of the metal floor. The whole antenna forms a radial line waveguide structure. The dielectric layer serves as the propagation medium of the radial line waveguide structure and can play a role in reducing losses for air. The holographic antenna radiation layer has an antenna radiation array, and the radiation units of the antenna radiation array are slot radiation units. By reasonably designing the positions and angles of the slot radiation units, linear polarization and circular polarization can be achieved, and linear polarization and circular polarization can also be achieved through beam scanning of the quantified slot radiation intensity.

[0083] The above is only a preferred embodiment of the present invention patent, but the implementation manner of the present invention is not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A broadband high-gain two-dimensional digital holographic antenna, characterized in that: The invention comprises a holographic antenna radiation layer, a dielectric layer, a metal floor and a feeding structure, wherein the dielectric layer is arranged between the holographic antenna radiation layer and the metal floor, the feeding structure is connected to the bottom layer of the metal floor, the top layer of the metal floor is surrounded by metal walls, the metal walls are connected to the holographic antenna radiation layer, the holographic antenna radiation layer comprises an antenna radiation array and a multi-layer dielectric substrate, the radiation units of the antenna radiation array are slot radiation units, and the slot radiation units are arranged on the multi-layer dielectric substrate.

2. The broadband high-gain two-dimensional digital holographic antenna according to claim 1, characterized in that: The multilayer dielectric substrate comprises a first dielectric substrate, a second dielectric substrate, a third dielectric substrate and a fourth dielectric substrate which are arranged in sequence; the slot radiation unit comprises a switch component, a bias circuit, a slot, a grounding metal hole and an avoidance metal hole; the bias circuit comprises a feeder and a choke branch; the avoidance metal hole comprises a metal connection hole and an avoidance circular groove; The grounding metal hole and the metal connection hole penetrate the first dielectric substrate, the second dielectric substrate and the third dielectric substrate; the switch component and the feeder are arranged on the first dielectric substrate, and the switch component is connected to the feeder; the choke branch is arranged on the third dielectric substrate; A metal layer is arranged on the fourth dielectric substrate as a common ground, the common ground is connected to the grounding metal hole, and the gap and the avoidance circular groove are etched on the common ground; the feeder is connected to the choke branch through the metal connection hole, and the center of the avoidance circular groove is set at the center of the metal connection hole; the second dielectric substrate, the third dielectric substrate and the fourth dielectric substrate are provided with depth control grooves corresponding to the gap positions.

3. The broadband high-gain two-dimensional digital holographic antenna according to claim 2, characterized in that: The gap includes a first rectangular gap and a second rectangular gap, the length of the first rectangular gap is greater than the length of the second rectangular gap, one of the short sides of the second rectangular gap is connected to the center of the first rectangular gap, and the two form a T-shaped gap as a whole, and the two short sides of the first rectangular gap and the other short side of the second rectangular gap are semicircular.

4. The broadband high-gain two-dimensional digital holographic antenna according to claim 3, characterized in that: The switch assembly includes a radio frequency switch and a switch pad, the switch pad includes a positive switch pad and a negative switch pad, the positive pole of the radio frequency switch is connected to the positive switch pad, the negative pole of the radio frequency switch is connected to the negative switch pad, the position of the negative switch pad corresponds to the position of the first rectangular gap, the position of the positive switch pad corresponds to the position of the second rectangular gap, the positive switch pad is connected to the starting end of the feeder, and the end of the feeder is connected to the metal connection hole.

5. The broadband high-gain two-dimensional digital holographic antenna according to claim 4, characterized in that: The feed line extends from the connection with the positive switch pad to the connection with the metal connection hole and is bent.

6. The broadband high-gain two-dimensional digital holographic antenna according to claim 2, characterized in that: The choke branch is a fan-shaped branch, and the center of the choke branch is correspondingly connected to the center of the metal connecting hole.

7. The broadband high-gain two-dimensional digital holographic antenna according to any one of claims 1 to 6, characterized in that: A square protrusion is arranged at the center of the bottom layer of the metal floor, and the feeding structure is connected to the square protrusion to feed in a radio frequency signal.

8. A method for designing a broadband high-gain two-dimensional digital holographic antenna according to any one of claims 1 to 7, characterized in that: The method is achieved by designing the position and angle of the slot radiation unit; When the holographic antenna is a linearly polarized holographic antenna, the method includes: taking the center of the antenna radiation array as the origin, setting up an x-axis and a y-axis in the transverse direction and the longitudinal direction respectively to establish a Cartesian coordinate system, the direction perpendicular to the long side of the slot away from the origin is the normal direction of the long side of the slot, the direction from the origin to the slot radiation unit is the radial direction, and the x-axis direction is the main polarization direction; firstly, the position and angle of the slot radiation unit in the first quadrant of the Cartesian coordinate system are designed, the position of the slot radiation unit in the first quadrant is arranged in a fan shape or a rectangle, the angle of the slot radiation unit in the first quadrant is that the angle between the normal direction of the long side of the slot and the main polarization direction is less than or equal to The angle between the normal direction of the long side of the slot and the radial direction is less than or equal to 45°, so as to satisfy the slot excitation radiation while suppressing the cross polarization; then the slot radiation unit in the second quadrant of the Cartesian coordinate system is the mirror arrangement of the slot radiation unit position and angle in the first quadrant relative to the y-axis; then the slot radiation unit in the third quadrant of the Cartesian coordinate system is the mirror arrangement of the slot radiation unit position and angle in the second quadrant relative to the x-axis; finally, the slot radiation unit in the fourth quadrant of the Cartesian coordinate system is the mirror arrangement of the slot radiation unit position and angle in the third quadrant relative to the y-axis, and the arrangement of the entire antenna radiation array is completed; When the holographic antenna is a circularly polarized holographic antenna, the method comprises: taking the center of the antenna radiation array as the origin, respectively setting up an x-axis and a y-axis in the transverse direction and the longitudinal direction to establish a Cartesian coordinate system, and the direction perpendicular to the long side of the slot away from the origin is the normal direction of the long side of the slot; firstly designing the position and angle of the slot radiation unit in the first quadrant of the Cartesian coordinate system, the position of the slot radiation unit in the first quadrant is arranged in a fan shape or a rectangle, and the angle of the slot radiation unit in the first quadrant is that the angle between the normal direction of the long side of the slot and the positive direction of the x-axis is 45 °, to satisfy the slot excitation radiation and realize circular polarization at the same time; then the slot radiation unit in the second quadrant of the Cartesian coordinate system is a mirror arrangement of the slot radiation unit position and angle in the first quadrant relative to the y-axis; then the slot radiation unit in the third quadrant of the Cartesian coordinate system is a mirror arrangement of the slot radiation unit position and angle in the second quadrant relative to the x-axis; finally, the slot radiation unit in the fourth quadrant of the Cartesian coordinate system is a mirror arrangement of the slot radiation unit position and angle in the third quadrant relative to the y-axis, and the entire antenna radiation array is arranged.

9. A method for designing a broadband high-gain two-dimensional digital holographic antenna according to any one of claims 1 to 7, characterized in that: The method is implemented by beam scanning to quantify the slot radiation intensity; When the holographic antenna is a linearly polarized holographic antenna, the method comprises: taking the center of the antenna radiation array as the origin, setting up an x-axis and a y-axis in the transverse direction and the longitudinal direction respectively to establish a Cartesian coordinate system, using the position of each slot radiation unit and the desired beam pointing direction, normalizing the radiation intensity of each slot radiation unit to obtain the normalized radiation intensity of each slot radiation unit; performing a threshold judgment on the normalized radiation intensity of each slot radiation unit, if the normalized radiation intensity of the slot radiation unit is greater than the set threshold, judging the radiation intensity of the slot radiation unit to be 1, and if the normalized radiation intensity of the slot radiation unit is less than or equal to the set threshold, judging the radiation intensity of the slot radiation unit to be 0; When the holographic antenna is a circularly polarized holographic antenna, the method includes: taking the center of the antenna radiation array as the origin, setting up an x-axis and a y-axis in the transverse direction and the longitudinal direction respectively to establish a Cartesian coordinate system, using the position of each slot radiation unit and the desired beam pointing direction, normalizing the radiation intensity of each slot radiation unit to obtain the normalized radiation intensity of each slot radiation unit with right-hand circular polarization and the normalized radiation intensity of each slot radiation unit with left-hand circular polarization; performing a threshold judgment on the normalized radiation intensity of each slot radiation unit, if the normalized radiation intensity of the slot radiation unit is greater than the set threshold, judging the radiation intensity of the slot radiation unit to be 1, and if the normalized radiation intensity of the slot radiation unit is less than or equal to the set threshold, judging the radiation intensity of the slot radiation unit to be 0.

10. A communication device, characterized in that: It comprises the broadband high-gain two-dimensional digital holographic antenna as described in any one of claims 1-7.

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