Ka-band orbital angular momentum filtering antenna

Abstract

The application belongs to the technical field of antennas and discloses a Ka-band orbital angular momentum filtering antenna, which comprises a filtering power divider; the filtering power divider is used for filtering and equally dividing received electromagnetic energy into several paths of electromagnetic waves; wherein the filtering power divider is in a whole annular three-dimensional structure; a phase shifter module is arranged at the bottom of the filtering power divider and is used for phase adjusting the several paths of electromagnetic waves to obtain several paths of electromagnetic signals with different phases; wherein the output end of the phase shifter module is bent towards the inner side of the bottom end of the filtering power divider; a twisted waveguide module is vertically arranged in the annular cavity of the filtering power divider and is used for converting the several paths of electromagnetic signals with different phases into several paths of electromagnetic signals with the same polarization direction; a horn antenna module is arranged above the twisted waveguide module and is used for receiving the several paths of electromagnetic signals with the same polarization direction and outputting several paths of OAM beams; the application has the characteristics of high antenna efficiency, large power capacity and strong out-of-band gain suppression capability.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, and specifically relates to a Ka-band orbital angular momentum filter antenna. Background Technology

[0002] Antennas are mainly used to convert energy between guided electromagnetic waves and radiated electromagnetic waves, playing a crucial role in wireless communication systems. Filter antennas, on the other hand, integrate frequency selectivity with out-of-band suppression capabilities into the antenna to effectively reduce the overall system size and improve the system's out-of-band anti-interference capability.

[0003] Orbital angular momentum (OAM) is a characteristic that exists in a specific beam. Specifically, orbital angular momentum carrying different topological values ​​makes the beams naturally orthogonal and does not interfere with each other. Therefore, with limited spectrum resources, orbital angular momentum can be used to greatly increase the information capacity carried by the beam without increasing the bandwidth, thereby realizing multiplexing. By loading different information onto beams carrying orbital angular momentum with different topological values, they can be transmitted in the same frequency band without interference, significantly improving channel capacity.

[0004] Currently, existing OAM antennas are mainly constructed using microstrip antennas and reflector antennas with planar printed circuit board technology. However, they have limitations in antenna efficiency, power capacity, and out-of-band interference suppression, making it difficult to meet the needs of future 5G / 6G communication. Summary of the Invention

[0005] To address the technical problems existing in the prior art, this invention provides a Ka-band orbital angular momentum filter antenna to solve the technical problem that existing OAM antennas are limited in terms of antenna efficiency, power capacity and out-of-band interference suppression, making it difficult to meet the technical requirements of future 5G / 6G communication.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] This invention provides a Ka-band orbital angular momentum filter antenna, comprising a power divider, a phase shifter module, a torsion waveguide module, and a horn antenna module; the power divider, the phase shifter module, the torsion waveguide module, and the horn antenna module are all air-filled all-metal structures;

[0008] The power divider is used to filter the received electromagnetic energy and divide the filtered electromagnetic energy into several electromagnetic waves; wherein, the power divider is a ring-shaped three-dimensional structure.

[0009] The phase shifter module is located at the bottom of the filter power divider and is used to adjust the phase of the several electromagnetic waves to obtain several electromagnetic signals with different phases; wherein, the output end of the phase shifter module is bent towards the inner side of the bottom end of the filter power divider.

[0010] The torsional waveguide module is vertically arranged in the annular cavity of the filter power divider, and is used to receive the several electromagnetic signals of different phases and convert the several electromagnetic signals of different phases into several electromagnetic signals with the same polarization direction.

[0011] The horn antenna module is positioned above the torsional waveguide module and is used to receive the several electromagnetic signals with the same polarization direction and output several OAM beams.

[0012] Furthermore, the power divider is a 1-to-8 power divider, capable of achieving an eleventh-order filter response and 1-to-8 power distribution. The 1-to-8 power divider is constructed from several rectangular cavities joined together, and the resonant mode of each rectangular cavity is TE. 101 model.

[0013] Furthermore, the power divider includes, from top to bottom, an input port, a first cavity unit layer, a second cavity unit layer, two third cavity unit layers, four fourth cavity unit layers, and eight output ports.

[0014] The upper end of the input port is used to connect to an external signal source, the lower end of the input port is connected to the upper end of the first cavity unit layer, and the lower end of the first cavity unit layer is connected to the middle of the upper end of the second cavity unit layer.

[0015] Two third cavity unit layers are symmetrically arranged at the lower ends of the second cavity unit layer; wherein, the first third cavity unit layer is located below the first end of the second cavity unit layer, and the bottom surface of the first end of the second cavity unit layer is connected to the middle of the upper end of the first third cavity unit layer; the second third cavity unit layer is located below the second end of the second cavity unit layer, and the bottom surface of the second end of the second cavity unit layer is connected to the middle of the upper end of the second third cavity unit layer.

[0016] Two of the fourth cavity unit layers are symmetrically arranged at the lower ends of the first third cavity unit layer, and the remaining two fourth cavity unit layers are symmetrically arranged at the lower ends of the second third cavity unit layer. Specifically, the upper middle part of the first fourth cavity unit layer is connected to the first bottom surface of the first third cavity unit layer, the upper middle part of the second fourth cavity unit layer is connected to the second bottom surface of the first third cavity unit layer, the upper middle part of the third fourth cavity unit layer is connected to the first bottom surface of the second third cavity unit layer, and the upper middle part of the fourth fourth cavity unit layer is connected to the second bottom surface of the second third cavity unit layer.

[0017] Each fourth cavity unit layer has two output ports at its lower ends; the upper end of each output port is connected to the bottom end of the fourth cavity unit layer.

[0018] Furthermore, the first cavity unit layer includes a rectangular cavity; the second cavity unit layer includes nine rectangular cavities arranged in an arc shape and connected in sequence; the third cavity unit layer includes five rectangular cavities arranged in an arc shape and connected in sequence; and the fourth cavity unit layer includes three rectangular cavities arranged in an arc shape and connected in sequence; wherein, the resonance mode of all the rectangular cavities is TE. 101 model.

[0019] Furthermore, the phase shifter module includes several U-shaped waveguide phase shifters, which are arranged in a ring array; wherein, the number of U-shaped waveguide phase shifters is the same as the number of electromagnetic waves output by the filter power divider 1, and each U-shaped waveguide phase shifter is formed by bending a rectangular waveguide by 180°.

[0020] Furthermore, the phase difference between the electromagnetic signals output by two adjacent U-shaped waveguide phase shifters is 45°.

[0021] Furthermore, the twisted waveguide module includes several vertically arranged twisted waveguide bodies, and the several twisted waveguide bodies are arranged in a ring array; the twisted waveguide body includes an input waveguide segment, a first twisted waveguide segment, a second twisted waveguide segment and an output waveguide segment arranged sequentially from bottom to top;

[0022] Wherein, both the input waveguide segment and the output waveguide segment are rectangular waveguides; the input waveguide segments in all the torsional waveguide bodies are arranged in a ring array, and the lower end of the input waveguide segment is used to connect to the corresponding output port of the phase shifter module; the output waveguide segments in all the torsional waveguide bodies are arranged in a ring array, and the upper end of the output waveguide segment is used to connect to the corresponding input port of the horn antenna module, and the major axis of the output waveguide segments in all the torsional waveguide bodies is arranged parallel to each other.

[0023] Furthermore, the horn antenna module includes several horn antenna bodies, which are arranged in a circular array, and the horn apertures of all the horn antenna bodies are oriented in the same direction.

[0024] Furthermore, the E-plane beamwidth of the horn antenna body is the same as the H-plane beamwidth.

[0025] Furthermore, under the condition of frequency of 25.9-29.9GHz, the reflection coefficient of the Ka-band orbital angular momentum filter antenna is less than -13dB, and the transmission coefficient is -9.2dB; the gain of the Ka-band orbital angular momentum filter antenna in the operating frequency band is 13.5dB.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] This invention provides a Ka-band orbital angular momentum filter antenna, which is composed of a filter power divider with an air-filled all-metal structure, a phase shifter module, a torsion waveguide module, and a horn antenna module. The filter power divider is configured as a ring-shaped three-dimensional structure, and the output end of the phase shifter module is bent inward towards the bottom end of the filter power divider. The polarization direction of the electromagnetic signal is converted by the torsion waveguide module, and then the OAM beam is output through the horn antenna module. This reduces the overall size of the antenna while effectively improving its out-of-band gain suppression capability. Due to the high mechanical strength of the all-metal structure, it can withstand high temperatures. Thermodynamically, it has the conditions to carry high-power electromagnetic energy. Electromagnetically, the air filling provides a high breakdown voltage, which provides a basis for carrying high-power electromagnetic energy. At the same time, the air-filled structure avoids dielectric loss, giving it inherently low loss and high efficiency characteristics. Therefore, it has the characteristics of high antenna efficiency, large power capacity, and strong out-of-band gain suppression capability.

[0028] Furthermore, the 1-to-8 filter power divider is composed of several rectangular resonant cavities and can achieve an eleventh-order filter response and a 1-to-8 power distribution function. It has the characteristics of small energy transmission fluctuation and low loss in the filter passband. At the same time, by adjusting the size and coupling of the metal resonant cavity, and applying the polynomial transformation corresponding to the coupling matrix and the equiripple filter, a high-order equiripple filter response can be achieved. In addition, its steep roll-off characteristics give the antenna strong out-of-band gain suppression capability. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of the Ka-band orbital angular momentum filter antenna described in the embodiment.

[0030] Figure 2 This is a schematic diagram of the filter power divider in the embodiment;

[0031] Figure 3 This is a schematic diagram of the phase shifter module in the embodiment;

[0032] Figure 4 This is a schematic diagram of the twisted waveguide module in the embodiment;

[0033] Figure 5 This is a schematic diagram of the horn antenna module in the embodiment;

[0034] Figure 6 The figure shows the simulation results of the scattering parameter amplitude of the filter power divider in the embodiment;

[0035] Figure 7 The radiation pattern of the horn antenna body in the embodiment under 28GHz conditions;

[0036] Figure 8 This is a simulated reflection coefficient curve of the Ka-band orbital angular momentum filter antenna described in the embodiment.

[0037] Figure 9 The simulated radiation pattern of the Ka-band orbital angular momentum filter antenna described in the embodiment;

[0038] Figure 10 The phase pattern of the Ka-band orbital angular momentum filter antenna described in the embodiment;

[0039] Figure 11 This is a graph showing the gain of the Ka-band orbital angular momentum filter antenna as a function of frequency, as described in the embodiment.

[0040] The components include: 1. Filter power divider; 2. Phase shifter module; 3. Torsional waveguide module; 4. Horn antenna module; 11. Input port; 12. First cavity unit layer; 13. Second cavity unit layer; 14. Third cavity unit layer; 15. Fourth cavity unit layer; 16. Output port; 21. U-shaped waveguide phase shifter; 31. Torsional waveguide body; 301. Input waveguide section; 302. First torsional waveguide section; 303. Second torsional waveguide section; 304. Output waveguide section; 41. Horn antenna body. Detailed Implementation

[0041] To make the technical problems solved by the present invention, the technical solutions, and the beneficial effects clearer, the following specific embodiments provide a further detailed description of the present invention. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0042] This invention provides a Ka-band orbital angular momentum filter antenna, comprising a power divider 1, a phase shifter module 2, a torsion waveguide module 3, and a horn antenna module 4; wherein the power divider 1, the phase shifter module 2, the torsion waveguide module 3, and the horn antenna module 4 are all air-filled all-metal structures.

[0043] The power divider 1 is used to filter the received electromagnetic energy and divide the filtered electromagnetic energy into several electromagnetic waves. The power divider 1 has a three-dimensional structure. The phase shifter module 2 is located at the bottom of the power divider 1 and is used to adjust the phase of the several electromagnetic waves to obtain several electromagnetic signals with different phases. The output end of the phase shifter module 2 is bent inward toward the bottom end of the power divider 1. The torsional waveguide module 3 is vertically arranged in the annular cavity of the power divider 1 and is used to receive the several electromagnetic signals with different phases and convert them into several electromagnetic signals with the same polarization direction. The horn antenna module 4 is located above the torsional waveguide module 3 and is used to receive the several electromagnetic signals with the same polarization direction and output several OAM beams.

[0044] The power divider 1 is a 1-to-8 power divider, capable of achieving an eleventh-order filter response and 1-to-8 power distribution. The 1-to-8 power divider is constructed from several rectangular cavities joined together, and the resonant mode of each rectangular cavity is TE. 101 Specifically, the power divider 1 is composed of several all-metal rectangular cavities resonating in the TE101 mode. By adjusting the size of the rectangular cavities and the size of the coupling diaphragms between the cavities, the power divider 1 can achieve an eleventh-order filtering response and have a steep roll-off characteristic, thereby enabling the antenna to have strong out-of-band gain suppression capability.

[0045] The phase shifter module 2 includes a plurality of U-shaped waveguide phase shifters 21, which are arranged in a ring array. The number of U-shaped waveguide phase shifters 21 is the same as the number of electromagnetic waves output by the filter power divider 1. Each U-shaped waveguide phase shifter 21 is formed by bending a rectangular waveguide by 180°. Preferably, the phase difference between the electromagnetic signals output by two adjacent U-shaped waveguide phase shifters 21 is 45°.

[0046] The torsional waveguide module 3 includes several vertically arranged torsional waveguide bodies 31, which are distributed in a ring array. Each torsional waveguide body 31 includes an input waveguide segment 301, a first torsional waveguide segment 302, a second torsional waveguide segment 303, and an output waveguide segment 304 arranged sequentially from bottom to top. The horn antenna module 4 includes several horn antenna bodies 41, which are distributed in a ring array, and all the horn antenna bodies 41 have the same horn aperture direction.

[0047] The Ka-band orbital angular momentum filter antenna of this invention is composed of a filter power divider, a phase shifter module, a torsional waveguide module, and a horn antenna module with an air-filled all-metal structure. That is, the filter power divider, phase shifter module, and torsional waveguide module are all made of all-metal resonant cavities or all-metal waveguides, which naturally have low loss characteristics. The all-metal horn antenna also has the characteristic of high radiation efficiency. Thanks to the application and integration of the low-loss structure of the all-metal structure, the antenna has the characteristics of high efficiency, large power capacity, and strong out-of-band interference suppression capability.

[0048] In this invention, the dielectric filling material of the power divider 1, the phase shifter module 2, the torsional waveguide module 3, and the horn antenna module 4 is all air and adopts a three-dimensional waveguide structure, which has a high breakdown voltage. Secondly, since the power capacity of electromagnetic devices is positively correlated with their breakdown voltage, the antenna can carry high electromagnetic energy. At the same time, the all-metal structure of this invention enables it to withstand high operating temperatures, which thermodynamically meets the requirements of high power capacity.

[0049] Working principle:

[0050] In the Ka-band orbital angular momentum filter antenna of the present invention, electromagnetic energy is fed in from the input port of the filter power divider 1. The filter power divider 1 filters the received electromagnetic energy to remove electromagnetic energy outside the operating frequency band and divides the filtered electromagnetic energy into several electromagnetic waves with equal power and consistent phase. Then, the several electromagnetic waves enter the corresponding U-shaped waveguide phase shifters in the phase shifter module 2. The phase of the corresponding electromagnetic waves is adjusted by the U-shaped waveguide phase shifters to add a preset offset to offset the phase offset generated by the subsequent torsional waveguide module 3. Subsequently, several electromagnetic signals with different phases, i.e., electromagnetic signals with phase pre-offset, enter the corresponding torsional waveguide body in the torsional waveguide module 3. The torsional waveguide body converts the several electromagnetic signals with different phases into several electromagnetic signals with the same polarization direction, so that the output electromagnetic signals have the same polarization direction. At the same time, the pre-offset is canceled by the phase shift of the torsional waveguide module 3, and the output electromagnetic signals have the same phase. Finally, the several electromagnetic signals with the same polarization direction and equal phase are input to the horn antenna module 4, thereby realizing OAM beam output.

[0051] Example

[0052] As attached Figure 1 As shown, this embodiment provides a Ka-band orbital angular momentum filter antenna, including a power divider 1, a phase shifter module 2, a torsional waveguide module 3, and a horn antenna module 4; the power divider 1, the phase shifter module 2, the torsional waveguide module 3, and the horn antenna module 4 are all air-filled all-metal structures.

[0053] The power divider 1 is used to filter the received electromagnetic energy to remove electromagnetic energy outside the operating frequency band and divide the filtered electromagnetic energy into eight electromagnetic waves. The phase shifter module 2 is located at the bottom of the power divider 1 and is used to adjust the phase of the eight electromagnetic waves to give them different phase pre-offsets, thereby obtaining eight electromagnetic signals with different phases. The torsional waveguide module 3 is vertically arranged in the annular cavity of the power divider 1 and is used to receive the eight electromagnetic signals with different phases and convert them into several electromagnetic signals with the same polarization direction. The horn antenna module 4 is located above the torsional waveguide module 3 and is used to receive the several electromagnetic signals with the same polarization direction and output several OAM beams.

[0054] As attached Figure 2As shown, the filter power divider 1 has an overall ring-shaped three-dimensional structure; wherein, the filter power divider 1 adopts a 1-to-8 filter power divider, which can realize an eleventh-order filter response and a 1-to-8 power distribution function; the 1-to-8 filter power divider is composed of 32 rectangular resonant cavities spliced ​​together, and the resonant mode of the rectangular resonant cavities is TE. 101 The process involves several steps. It should be noted that during the fabrication of the power divider 1, 32 rectangular cavities are first sequentially assembled to form a planar 1-to-8 power divider. Then, the planar 1-to-8 power divider is bent to form a ring-shaped three-dimensional 1-to-8 power divider, facilitating power feeding between it and the phase shifter module 2.

[0055] Specifically, the power divider 1 includes an input port 11, a first cavity unit layer 12, a second cavity unit layer 13, two third cavity unit layers 14, four fourth cavity unit layers 15, and eight output ports arranged in layers from top to bottom.

[0056] The upper end of the input port 11 is used to connect to an external signal source, and the lower end of the input port 11 is connected to the upper end of the first cavity unit layer 12. Preferably, both the input port 11 and the first cavity unit layer 12 include a rectangular cavity. The lower end of the first cavity unit layer 12 is connected to the middle of the upper end of the second cavity unit layer 13, and two third cavity unit layers 14 are symmetrically arranged at the lower ends of the second cavity unit layer 13. The first third cavity unit layer is located below the first end of the second cavity unit layer 13, and the bottom surface of the first end of the second cavity unit layer 13 is connected to the middle of the upper end of the first third cavity unit layer. The second third cavity unit layer is located below the second end of the second cavity unit layer 13, and the bottom surface of the second end of the second cavity unit layer 13 is connected to the middle of the upper end of the second third cavity unit layer. Preferably, the second cavity unit layer 13 includes nine rectangular cavities arranged in an arc shape and connected in sequence, and each third cavity unit layer 14 includes five rectangular cavities arranged in an arc shape and connected in sequence.

[0057] All four fourth cavity unit layers 15 are disposed below the third cavity unit layer 14, with two fourth cavity unit layers 15 symmetrically disposed at the lower ends of the first third cavity unit layer, and the remaining two fourth cavity unit layers 15 symmetrically disposed at the lower ends of the second third cavity unit layer. Specifically, the upper middle part of the first fourth cavity unit layer is connected to the first bottom surface of the first third cavity unit layer, the upper middle part of the second fourth cavity unit layer is connected to the second bottom surface of the first third cavity unit layer, and the upper middle part of the third fourth cavity unit layer is connected to the second bottom surface of the second third cavity unit layer. The first end bottom surface of the layer is connected, and the upper middle part of the fourth fourth cavity unit layer is connected to the second end bottom surface of the second third cavity unit layer; each of the fourth cavity unit layers 15 has two output ports 16 at its lower ends, the upper end of the output port 16 is connected to the end bottom surface of the fourth cavity unit layer 15, and the lower end of the output port 16 is used to connect to the U-shaped waveguide phase shifter 21 in the phase shifter module 2; preferably, each fourth cavity unit layer 15 includes three rectangular cavities distributed in an arc shape and connected in sequence, and each output port 16 includes one rectangular cavity.

[0058] As attached Figure 3 As shown, the phase shifter module 2 includes eight U-shaped waveguide phase shifters 21, which are arranged in a ring array. Each U-shaped waveguide phase shifter 21 is formed by bending a rectangular waveguide by 180° to facilitate the miniaturization of the antenna. Specifically, the eight U-shaped waveguide phase shifters 21 are arranged in a one-to-one correspondence with the eight output ports 16, and the input end of the U-shaped waveguide phase shifter 21 is connected to the lower end of the output port 16. By adjusting the length of the U-shaped waveguide phase shifters 21, the phase difference between the electromagnetic signals output by two adjacent U-shaped waveguide phase shifters 21 is 45°. That is, the eight U-shaped waveguide phase shifters 21 sequentially assign 45°, 90°, 135°, 180°, 225°, 270°, 315°, and 360° phases to the eight fed electromagnetic waves to cancel the phase shift generated by the subsequent twisted waveguide module 3.

[0059] As attached Figure 4 As shown, the twisted waveguide module 3 includes eight twisted waveguide bodies 31 arranged vertically, and the eight twisted waveguide bodies 31 are arranged in a ring array and are arranged one-to-one with the eight U-shaped waveguide phase shifters 21; wherein, the lower end of the twisted waveguide body 31 is connected to the output end of the U-shaped waveguide phase shifter 21, and the upper end of the twisted waveguide body 31 is used to connect to the horn antenna body 41 in the horn antenna module 4.

[0060] Specifically, the torsional waveguide body 31 includes an input waveguide segment 301, a first torsional waveguide segment 302, a second torsional waveguide segment 303, and an output waveguide segment 304 arranged sequentially from bottom to top; both the input waveguide segment 301 and the output waveguide segment 304 are rectangular waveguides; all the input waveguide segments 301 in the torsional waveguide body 31 are arranged in a ring array, and the lower end of the input waveguide segment 301 is connected to the output end of the corresponding U-shaped waveguide phase shifter 21; all the output waveguide segments 304 in the torsional waveguide body 31 are arranged in a ring array, and the upper end of the output waveguide segment 304 is connected to the horn antenna body 41 in the horn antenna module 4, and the long axis direction of all the output waveguide segments 304 in the torsional waveguide body 31 is parallel; the first torsional waveguide segment 302 and the second torsional waveguide segment 303 are sequentially arranged between the input waveguide segment 301 and the output waveguide segment 304.

[0061] It should be noted that in the rectangular waveguides of the input waveguide section 301 and the output waveguide section 304, the polarization direction of the electromagnetic wave is parallel to the short side direction of the rectangular waveguide. Since the power divider 1 is arranged in a spatial three-dimensional ring, the short side directions of its output ports are different for each port. However, in the first torsional waveguide section 302 and the second torsional waveguide 303, the polarization of the electromagnetic wave changes with the torsion angle and eventually becomes parallel to the short side direction of the output port of the output waveguide section 304. Therefore, based on the relative position of the output ports of the power divider 1, the first torsional waveguide section 302 and the second torsional waveguide 303 are used to achieve a preset torsion angle from the input waveguide section 301 to the output waveguide section 304, so that the eight electromagnetic signals output by the torsional waveguide module 3 have the same polarization direction, thereby achieving the same polarization direction for the eight output ports.

[0062] As attached Figure 5 As shown, the horn antenna module 4 includes eight horn antenna bodies 41, which are arranged in a ring array and have the same horn aperture direction. Specifically, the eight horn antenna bodies 41 are connected one-to-one with the output waveguide segments 304 in the eight torsional waveguide bodies 31. All horn antenna bodies 41 are located on the same horizontal plane, and the E-plane beamwidth of the horn antenna body 41 is the same as the H-plane beamwidth.

[0063] As attached Figure 6 As shown, attached Figure 6 The simulation results of the scattering parameter amplitude of the filter power divider in the embodiment are given in the figure; from the appendix Figure 6As can be seen, the antenna has a reflection coefficient of less than -13dB and a transmission coefficient of approximately -9.2dB within the 25.9–29.9 GHz range. It also has an eleventh-order filtering response, thus possessing the characteristics of small energy transmission fluctuations and low losses in the filter passband. At the same time, the roll-off characteristics of the eleventh-order filtering response are good, with a very steep roll-off outside the passband, achieving a significant out-of-band suppression effect.

[0064] As attached Figure 7 As shown, attached Figure 7 The radiation pattern of the horn antenna body in the embodiment under 28GHz conditions is shown in the appendix; Figure 7 As can be seen, the horn antenna body has a 3dB beamwidth of 63° at phi = 0°; the unit antenna has a 3dB beamwidth of 63° at phi = 90°; the beamwidths of the E-plane and H-plane of the horn antenna body are the same, ensuring that the phase pattern of the formed OAM beam is symmetrical and the modal purity is high.

[0065] As attached Figure 8 As shown, attached Figure 8 The attached figure shows the simulated reflection coefficient curve of the Ka-band orbital angular momentum filter antenna described in the embodiment; from the attached figure... Figure 8 As can be seen, the Ka-band orbital angular momentum filter antenna has a reflection coefficient of less than -13dB in the range of 25.9 to 29.9 GHz.

[0066] As attached Figure 9 As shown, attached Figure 9 The simulation radiation pattern of the Ka-band orbital angular momentum filter antenna described in the embodiment is given in the appendix; Figure 9 As can be seen, the antenna has a radiation null point in the normal direction. The reason for this is that the phase of the OAM beam changes drastically in the main radiation direction, causing the radiated energy to cancel each other out, resulting in a significant reduction in radiation intensity and the appearance of a radiation null point.

[0067] As attached Figure 10 As shown, attached Figure 10 The image shows the phase pattern of the Ka-band orbital angular momentum filter antenna described in the embodiment; from the appendix... Figure 10 As can be seen, the phase of the radiated energy of the antenna exhibits a vortex change at the center, which meets the conditions for OAM beams, and its radiation mode should be the +1 mode.

[0068] As attached Figure 11 As shown, attached Figure 11 The figure shows the gain versus frequency curve of the Ka-band orbital angular momentum filter antenna described in the embodiment; from the appendix... Figure 11 As can be seen, the antenna has a gain of approximately 13.5 dBi within its operating frequency band, which rapidly attenuates outside the operating bandwidth.

[0069] Manufacturing process:

[0070] The antenna fabrication process described in this embodiment is as follows: an antenna substrate is obtained by integral molding using photopolymerization additive manufacturing process; the antenna substrate is then surface-metallized using chemical copper plating to obtain the Ka-band orbital angular momentum filter antenna.

[0071] In this embodiment, the 1-to-8 filter power divider uses 32 resonant transistors in TE. 101 The 1-to-8 power divider is constructed by splicing together rectangular cavities. By adjusting the size of the rectangular cavities and the coupling between them, the 1-to-8 power divider can simultaneously achieve an eleventh-order filter response and an eight-to-one power distribution function. The eleventh-order filter response has a steep roll-off characteristic, significantly improving the out-of-band rejection level of this embodiment. Secondly, the 1-to-8 power divider is bent into a ring-shaped three-dimensional structure through a planar structure, which facilitates feeding with the subsequent phase shifter 2. In addition, the eight horn antenna bodies are fed by the eight torsional waveguide bodies respectively. The eight horn antenna bodies are arranged in a ring on the same horizontal plane, and the horn apertures of the eight horn antenna bodies are aligned. By adjusting the angle of the horn E-plane, the horn length, and the width of the H-plane of the eight horn antenna bodies, the amplitude and phase of the electromagnetic field at the radiating aperture can be controlled so that the beamwidths of the radiation patterns on the E-plane and H-plane are approximately the same, ensuring that the phase pattern of the formed OAM beam is symmetrical and has high modal purity.

[0072] In this invention, when electromagnetic energy is fed into the filter power divider, the electromagnetic energy mode in the single-input single-output rectangular cavity is TE. 101 Electromagnetic energy couples between the rectangular cavities at the input ports, forming a filtered response; electromagnetic energy forms a TE signal in a single-input, multi-output metal resonant cavity. 201 The system can achieve a 1-to-2 equal power distribution response; by cascading rectangular cavities, the power divider can ultimately achieve a 1-to-8 filtered power divider response. The power divider is composed of multi-order metallic rectangular cavities. By adjusting the size and coupling of the metallic cavities and applying the polynomial transformation corresponding to the coupling matrix and the equiripple filter, a high-order equiripple filter response can be achieved. Its steep roll-off characteristic gives the antenna strong out-of-band gain suppression capability.

[0073] The Ka-band orbital angular momentum filter antenna described in this invention comprises an air-filled all-metal structure, including a power divider, a phase shifter module, a torsion waveguide module, and a horn antenna module. Metal structures possess high mechanical strength and can withstand high temperatures, providing thermodynamic support for carrying high-power electromagnetic energy. Furthermore, air filling provides a high breakdown voltage, offering electromagnetic support for carrying high-power electromagnetic energy. Simultaneously, the air-filled structure avoids dielectric loss, naturally resulting in low loss and high efficiency.

[0074] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. A Ka-band orbital angular momentum filter antenna, characterized in that, It includes a power divider (1), a phase shifter module (2), a torsion waveguide module (3), and a horn antenna module (4); the power divider (1), the phase shifter module (2), the torsion waveguide module (3), and the horn antenna module (4) are all air-filled all-metal structures; The power divider (1) is used to filter the received electromagnetic energy and divide the filtered electromagnetic energy into several electromagnetic waves; wherein, the power divider (1) has a ring-shaped three-dimensional structure. The power divider (1) is a 1-to-8 power divider, which can achieve an eleventh-order filter response and a 1-to-8 power distribution function; wherein, the 1-to-8 power divider is composed of several rectangular cavities spliced ​​together, and the resonant mode of the rectangular cavities is TE. 101 model; The phase shifter module (2) is located at the bottom of the filter power divider (1) and is used to adjust the phase of the several electromagnetic waves to obtain several electromagnetic signals with different phases; wherein, the output end of the phase shifter module (2) is bent toward the inner side of the bottom end of the filter power divider (1); The torsional waveguide module (3) is vertically arranged in the annular cavity of the filter power divider (1) to receive the electromagnetic signals of different phases and convert the electromagnetic signals of different phases into electromagnetic signals with the same polarization direction. The horn antenna module (4) is disposed above the torsional waveguide module (3) and is used to receive the several electromagnetic signals with the same polarization direction and output several OAM beams. The power divider (1) includes an input port (11), a first cavity unit layer (12), a second cavity unit layer (13), two third cavity unit layers (14), four fourth cavity unit layers (15), and eight output ports (16) arranged in layers from top to bottom. The phase shifter module (2) includes several U-shaped waveguide phase shifters (21), which are arranged in a ring array. The number of U-shaped waveguide phase shifters (21) is the same as the number of electromagnetic waves output by the filter power divider 1. Each U-shaped waveguide phase shifter (21) is formed by bending a rectangular waveguide by 180°. The lower end of the output port (16) is connected to the input end of the U-shaped waveguide phase shifter (21).

2. The Ka-band orbital angular momentum filter antenna according to claim 1, characterized in that, The upper end of the input port (11) is used to connect to an external signal source, the lower end of the input port (11) is connected to the upper end of the first cavity unit layer (12), and the lower end of the first cavity unit layer (12) is connected to the middle of the upper end of the second cavity unit layer (13). Two third cavity unit layers (14) are symmetrically arranged at the lower ends of the second cavity unit layer (13); wherein, the first third cavity unit layer is located below the first end of the second cavity unit layer (13), and the bottom surface of the first end of the second cavity unit layer (13) is connected to the middle of the upper end of the first third cavity unit layer; the second third cavity unit layer is located below the second end of the second cavity unit layer (13), and the bottom surface of the second end of the second cavity unit layer (13) is connected to the middle of the upper end of the second third cavity unit layer; Two of the fourth cavity unit layers (15) are symmetrically arranged at the lower ends of the first third cavity unit layer, and the remaining two fourth cavity unit layers (15) are symmetrically arranged at the lower ends of the second third cavity unit layer; specifically, the upper middle part of the first fourth cavity unit layer is connected to the first bottom surface of the first third cavity unit layer, the upper middle part of the second fourth cavity unit layer is connected to the second bottom surface of the first third cavity unit layer, the upper middle part of the third fourth cavity unit layer is connected to the first bottom surface of the second third cavity unit layer, and the upper middle part of the fourth fourth cavity unit layer is connected to the second bottom surface of the second third cavity unit layer; Each fourth cavity unit layer (15) has two output ports (16) at its lower ends; wherein the upper end of the output port (16) is connected to the bottom end of the fourth cavity unit layer (15).

3. A Ka-band orbital angular momentum filter antenna according to claim 2, characterized in that, The first cavity unit layer (12) includes a rectangular cavity; the second cavity unit layer (13) includes nine rectangular cavities arranged in an arc shape and connected in sequence; the third cavity unit layer (14) includes five rectangular cavities arranged in an arc shape and connected in sequence; the fourth cavity unit layer (15) includes three rectangular cavities arranged in an arc shape and connected in sequence; wherein, the resonance mode of all the rectangular cavities is TE. 101 model.

4. A Ka-band orbital angular momentum filter antenna according to claim 1, characterized in that, The phase difference between the electromagnetic signals output by two adjacent U-shaped waveguide phase shifters (21) is 45°.

5. A Ka-band orbital angular momentum filter antenna according to claim 1, characterized in that, The twisted waveguide module (3) includes a plurality of vertically arranged twisted waveguide bodies (31), and the plurality of twisted waveguide bodies (31) are arranged in a ring array; the twisted waveguide body (31) includes an input waveguide segment (301), a first twisted waveguide segment (302), a second twisted waveguide segment (303) and an output waveguide segment (304) arranged sequentially from bottom to top. The input waveguide segment (301) and the output waveguide segment (304) are both rectangular waveguides; the input waveguide segments (301) in all the torsional waveguide bodies (31) are arranged in a ring array, and the lower end of the input waveguide segment (301) is used to connect to the corresponding output port of the phase shifter module (2); the output waveguide segments (304) in all the torsional waveguide bodies (31) are arranged in a ring array, and the upper end of the output waveguide segment (304) is used to connect to the corresponding input port of the horn antenna module (4), and the long axis of the output waveguide segments (304) in all the torsional waveguide bodies (31) is parallel.

6. A Ka-band orbital angular momentum filter antenna according to claim 1, characterized in that, The horn antenna module (4) includes several horn antenna bodies (41), which are arranged in a ring array, and the horn apertures of all the horn antenna bodies (41) are aligned.

7. A Ka-band orbital angular momentum filter antenna according to claim 6, characterized in that, The beamwidth of the E-plane pattern of the horn antenna body (41) is the same as that of the H-plane pattern.

8. A Ka-band orbital angular momentum filter antenna according to claim 1, characterized in that, Under the condition of frequency 25.9-29.9GHz, the reflection coefficient of the Ka-band orbital angular momentum filter antenna is less than -13dB and the transmission coefficient is -9.2dB; the gain of the Ka-band orbital angular momentum filter antenna in the operating frequency band is 13.5dB.

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