Broadband high-isolation millimeter wave dual-circular polarization multi-beam antenna

Abstract

The invention discloses a broadband high-isolation millimeter wave dual-circular polarization multi-beam antenna, which comprises a 3D printing medium polarization grating lens and a millimeter wave dual-linear polarization antenna array, and is characterized in that the millimeter wave dual-linear polarization antenna array is located on a horizontal focal plane of the 3D printing medium polarization grating lens. Wherein the millimeter wave dual-line polarized antenna array adopts a folded medium integrated waveguide structure for feeding, so that high isolation is realized. A planarized millimeter wave dual-line polarization antenna array is used as a feed source antenna, and dual-line polarization-dual circular polarization conversion is realized through a 3D printing medium polarization grating lens; and the horizontal and vertical components of the + / -45-degree dual-linear polarized waves are equal in amplitude after passing through the polarized grating lens, and the phase difference is 90 degrees, so that dual-circular polarized waves are formed. The feed source array and the lens are arranged in a spaced mode, high gain and + / -45-degree scanning coverage are achieved, the design problem of a traditional dual-circular-polarization feed source is avoided, the complexity and cost of the system are remarkably reduced, and the deployment feasibility of a 5G / 6G millimeter wave terminal is improved.

Description

Technical Field

[0001] The present invention belongs to the field of antenna technology, and specifically relates to a broadband high-isolation millimeter-wave dual-circular polarization multi-beam antenna, specifically a millimeter-wave broadband high-isolation dual-circular polarization multi-beam antenna used in the fields of 5G / 6G millimeter-wave communication and satellite communication. Background Art

[0002] Antennas play a key role in transmitting and receiving electromagnetic signals in wireless communication systems, and their presence directly impacts the quality and performance of wireless communications. Multibeam antenna arrays can generate multiple, high-gain beams in different directions, thereby expanding communication coverage and enhancing communication quality. They offer high flexibility and a wide scanning range. Circularly polarized (CP) antennas effectively reduce polarization mismatch, suppress multipath interference, and mitigate Faraday rotation, making them widely used in communication systems. Dual circularly polarized antennas can increase channel capacity and mitigate multipath fading, transmitting twice the amount of data within the same spectrum while reducing the number of antennas required and conserving antenna space. Therefore, the design of millimeter-wave dual circularly polarized multibeam antennas is of great significance for 5G / 6G millimeter-wave communications and satellite communications.

[0003] The design of a dual circularly polarized antenna as a feed structure is challenging and often limited by bandwidth and isolation. In contrast, dual linearly polarized (LP) antennas are more easily able to achieve wider bandwidth and higher isolation. Substrate integrated waveguide (SIW) technology has attracted considerable attention in recent years due to its low loss, low cost, and applicability to the millimeter-wave frequency band. Many millimeter-wave antennas utilize SIW resonant cavity feeding, but dual-polarized antennas fed by a single SIW cavity typically have low port isolation, while using dual SIW resonant cavities for separate feeding results in excessive antenna size. Folded substrate integrated waveguide (FSIW) is an effective solution for miniaturizing SIW cavities. Compared to the semi-open structure of 1 / N-mode SIW resonators, which suffer from radiation leakage, FSIW resonators have better self-shielding properties. Therefore, research on millimeter-wave dual linearly polarized antennas fed by FSIW resonant cavities is of great significance.

[0004] Polarization gratings can efficiently convert dual linear polarization waves into dual circular polarization waves. Using dual linear polarization antennas as feed sources and implementing dual circular polarization antenna arrays through polarization gratings can significantly reduce design complexity. With the advancement of 3D printing technology, the manufacturing cost of dielectric polarization gratings has been significantly reduced. A dielectric polarization grating is a typical polarization grating structure that creates anisotropic properties through a periodic dielectric-air grid. This property can alter the phase difference between horizontally and vertically polarized electromagnetic waves, thereby achieving linear-to-circular polarization conversion. By adjusting the dielectric-to-air ratio and height parameters, the conversion bandwidth from linear polarization to circular polarization can be flexibly adjusted, demonstrating excellent designability. Therefore, the use of 3D-printed dielectric polarization gratings is highly suitable for implementing dual circularly polarized multi-beam antennas.

[0005] The present invention proposes a broadband, high-isolation millimeter-wave dual-circularly polarized multi-beam antenna based on a 3D-printed dielectric polarization grating lens, which has great application prospects in the fields of 5G / 6G millimeter-wave communications and satellite communications. Summary of the Invention

[0006] The purpose of the present invention is to address the shortcomings of the existing technology and provide a millimeter-wave dual-circular polarization multi-beam antenna based on a 3D-printed medium polarization grating lens. The antenna has the characteristics of broadband and high isolation, a beam scanning range of ±45°, and an axial ratio of less than 3dB within the scanning range. It can be applied to millimeter-wave communication and satellite communication.

[0007] A broadband, high-isolation millimeter-wave dual-circularly polarized multi-beam antenna based on a 3D-printed medium polarization grating lens, comprising a 3D-printed medium polarization grating lens and a millimeter-wave dual-linear polarization antenna array located directly below the 3D-printed medium polarization grating lens, wherein a first gap exists between the millimeter-wave dual-linear polarization antenna array and the 3D-printed medium polarization grating lens; The millimeter-wave dual-linear polarization antenna array is located on the horizontal focal plane of the 3D-printed medium polarization grating lens; the millimeter-wave dual-linear polarization antenna array is composed of a plurality of millimeter-wave dual-linear polarization antenna units fed by FSIW resonant cavities arranged in a plane, parallel to the 3D-printed medium polarization grating lens, and the centers of all millimeter-wave dual-linear polarization antenna units fed by FSIW resonant cavities are located on the same straight line; a second gap exists between adjacent millimeter-wave dual-linear polarization antenna units fed by FSIW resonant cavities; The 3D-printed medium polarization grating lens includes a lens holder, a lower lens, and an upper lens; the lower lens and the upper lens each have multiple layers, and each layer includes a main medium spindle unit and n sub-medium spindle units whose center passes through the main medium spindle unit, where n>1, and there is an air layer between adjacent sub-medium spindle units; the n sub-medium spindle units have a trend of gradually decreasing size along the axis of the main medium spindle unit, conforming to the refractive index distribution equivalent to that of a Luneburg lens; The medium spindle units of each layer of the lower lens and the medium spindle units of each layer of the upper lens are different in main axis direction and arrangement direction, but the number, shape and size of the medium spindle units are the same.

[0008] Preferably, the number of layers of the lower lens is greater than that of the upper lens (1-3).

[0009] Preferably, the main axis of the medium spindle unit of the lower lens points to the longitudinal direction and is arranged transversely along the horizontal direction, while the main axis of the medium spindle unit of the upper lens points to the horizontal direction and is arranged transversely along the longitudinal direction.

[0010] Preferably, the 3D printing medium polarization grating lens is cylindrical.

[0011] Preferably, the millimeter-wave dual-linear polarization antenna unit comprises, from bottom to top, a first metal surface, a first dielectric substrate, a second metal surface, a second dielectric substrate, a third dielectric substrate, a third metal surface, a fourth dielectric substrate, a fifth dielectric substrate, a fourth metal surface, a radiating patch, and a plurality of first metal holes, a plurality of second metal holes, at least one third metal hole, and a plurality of fourth metal holes. The first metal holes all extend through the first metal surface, the first dielectric substrate, the second dielectric substrate, the third dielectric substrate, and the third metal surface; the second metal holes and the third metal holes all extend through the first metal surface, the first dielectric substrate, the second metal surface, the second dielectric substrate, the third dielectric substrate, and the third metal surface. The fourth metal hole extends through the fifth dielectric substrate and the fourth metal surface. The plurality of first metal holes, the first metal surface, the first dielectric substrate, the second metal surface, the second dielectric substrate, the third dielectric substrate, and the third metal surface form two mutually orthogonal back-to-back FSIW resonant cavities, each with a feeding port.

[0012] Preferably, the second dielectric substrate is arranged between the first dielectric substrate and the third dielectric substrate; the fourth dielectric substrate is arranged between the third dielectric substrate and the fifth dielectric substrate; the first metal surface is located on the back of the first dielectric substrate; The second metal surface is located between the first dielectric substrate and the second dielectric substrate and is the middle metal layer of the FSIW resonant cavity. The second metal surface includes two FSIW resonant cavity middle layers that are orthogonally distributed, and there is a third gap between the two FSIW resonant cavity middle layers. The two FSIW resonant cavity middle layers have the same structure, both of which have a rectangular gap on the rectangular metal sheet and a rectangular notch on one of the outer edges. A feeding stripline connected to the rectangular metal sheet is provided in the rectangular notch. The feeding striplines of the two FSIW resonant cavity middle layers are orthogonally distributed. The rectangular gap can extend the current path to reduce the mode TE. 1.5,0,1 The resonant frequency of the two FSIW resonant cavity intermediate layers are respectively located in two back-to-back FSIW resonant cavities; each FSIW resonant cavity intermediate layer is provided with a plurality of second metal holes on the edge, and at least one third metal hole is provided therein; The third metal surface is located between the third dielectric substrate and the fourth dielectric substrate and serves as the metal ground of the FSIW resonant cavity; the third metal surface is provided with a T-shaped radiation slot for antenna coupling and feeding; A notch is formed in the fourth metal surface, a radiation patch is arranged in the notch, and a distance exists between the radiation patch and the fourth metal surface; a plurality of fourth metal holes are arranged around the notch of the fourth metal surface.

[0013] Preferably, the control mode TE is realized by adjusting the distance between the third metal hole and the second metal hole. 0.5,0,1 The resonant frequency of the mode TE is affected by adjusting the distance between the rectangular gap and the second metal hole.1.5,0,1 resonant frequency.

[0014] Preferably, the radiation patch is an axisymmetric structure, which includes at least one first sub-radiation patch, at least one second sub-radiation patch and at least one third sub-radiation patch, and there is a gap between adjacent sub-radiation patches.

[0015] Preferably, the dielectric constants of the main dielectric spindle unit and the sub-dielectric spindle unit of each layer are Satisfies the following formula: Formula (1) Where r represents the distance between the sub-medium spindle unit and the center of the main medium spindle unit, and D represents the diameter of the 3D printing medium polarization grid lens (1).

[0016] Preferably, the radius r of the main dielectric spindle unit and the daughter dielectric spindle unit is a function of the y-axis coordinate position, satisfying the following formula: Formula (2) in are the dielectric constants of the dielectric spindle material and the air layer between adjacent sub-dielectric spindle units, respectively; H represents the height of a dielectric spindle unit including an air layer, represents the distance from the center of the main medium spindle unit in the x-axis direction, and y represents the distance from the center of the main medium spindle unit in the y-axis direction.

[0017] The present invention realizes multi-mode resonance of the FSIW resonant cavity through rectangular gaps and a third metal hole, thereby expanding the antenna bandwidth and achieving high isolation. The dielectric spindle units in the three-dimensional 3D-printed dielectric polarization grating lens have different dielectric constants for the 0° and 90° components of the 45° polarized incident wave. The different relative dielectric constants cause a phase difference between the two mutually orthogonal components. As a phase compensation structure of the overall lens, the arrangement direction of the dielectric spindle units in each layer of the upper lens is orthogonal to that of the lower lens. The phase difference generated when the electromagnetic wave penetrates the upper lens will be reduced in the opposite direction, and the phase difference passing through the lens will be maintained at approximately 90°. By adjusting the diameter of the 3D-printed dielectric polarization grating lens, the radius r of the dielectric spindle units, the number of layers of the upper and lower lenses, and the phase compensation of the upper lens as the overall lens, the ±45° dual linear polarization wave is ultimately converted into a dual circular polarization wave. The beam scanning range covers ±45°, and the axial ratio is stabilized below 3dB.

[0018] The broadband high-isolation millimeter-wave dual circularly polarized multi-beam antenna proposed in the present invention has the following advantages: (1) The millimeter-wave dual-polarized antenna array fed by the FSIW resonant cavity proposed in the present invention realizes multi-mode resonance of the FSIW resonant cavity by etching gaps and adding metal holes, and has the characteristics of broadband and high isolation; the antenna array can be planarized and can be manufactured by standard PCB manufacturing process.

[0019] (2) The dielectric lens polarization grating proposed in the present invention, which is based on 3D printing technology, is constructed with dielectric spindles as units, ensuring that linearly polarized waves can be converted into circularly polarized waves when the planar feed array is scanned at a large angle. Based on the phase compensation principle, the phase difference between the horizontal and vertical components of the 45° polarized electromagnetic wave is maintained at close to 90° when the lens size is adjusted, achieving high gain while also achieving a stable axial ratio bandwidth. (3) The broadband, high-isolation millimeter-wave dual-circularly polarized multi-beam antenna proposed in this invention uses a planar millimeter-wave dual-linear polarization antenna array as the feed antenna. A 3D-printed medium polarization grating lens is used to achieve dual-linear polarization-dual-circular polarization conversion. The horizontal and vertical components of the ±45° dual-linear polarization wave have equal amplitudes and a 90° phase difference after passing through the polarization grating lens, forming a dual-circular polarization wave. The gap between the feed array and the lens is arranged to achieve high gain and ±45° scanning coverage, circumventing the design difficulties of traditional dual-circular polarization feeds, significantly reducing system complexity and cost, and improving the feasibility of 5G / 6G millimeter-wave terminal deployment.

[0020] In summary, the antenna of the present invention adopts the collaborative design of FSIW multi-mode resonant feed array and phase-compensated polarization grating lens to achieve dual-circularly polarized multi-beam radiation with broadband, high isolation, large-angle scanning, and stable axial ratio, meeting the high-capacity requirements of millimeter-wave communication and wide coverage of satellite communication. In addition, the antenna requires low cost and simple design structure, which can improve the integration of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 This is a schematic diagram of the overall structure of a broadband, high-isolation millimeter-wave dual-circularly polarized multi-beam antenna provided by an embodiment of the present invention.

[0023] Figure 2 A schematic top view of a millimeter-wave dual-linear polarization antenna array provided in an embodiment of the present invention; Figure 3 A bottom-up schematic diagram of a millimeter-wave dual-linear polarization antenna array provided in an embodiment of the present invention; Figure 4A schematic diagram of the three-dimensional structure of a millimeter-wave dual-linear polarization antenna unit fed by an FSIW resonant cavity provided in an embodiment of the present invention; Figure 5 A schematic diagram of the cross-sectional structure of the FSIW resonant cavity of the millimeter-wave dual-linear polarization antenna unit provided in an embodiment of the present invention; Figure 6 A schematic top view of a radiation patch of a millimeter-wave dual-linear polarization antenna unit provided in an embodiment of the present invention; Figure 7 A schematic diagram of the layered three-dimensional structure of a 3D printed medium polarization grating lens provided in an embodiment of the present invention; Figure 8 A schematic diagram of the three-dimensional structure of a dielectric spindle unit of a 3D-printed dielectric polarization grating lens provided in an embodiment of the present invention; Figure 9 A schematic diagram of a discretized horizontal section of a 3D-printed medium polarization grating lens provided by an embodiment of the present invention; Figure 10 A schematic cross-sectional view of the upper and lower layers of a 3D printed medium polarization grating lens provided by an embodiment of the present invention; Figure 11 The reflection coefficient and isolation of each port of the millimeter-wave dual-polarization antenna unit fed by the FSIW resonant cavity provided in the embodiment of the present invention; Figure 12 The left-handed circularly polarized multi-beam radiation pattern in the horizontal direction simulated at 28 GHz for the millimeter-wave dual circularly polarized multi-beam antenna provided in an embodiment of the present invention; Figure 13 The right-handed circularly polarized multi-beam radiation pattern in the horizontal direction simulated at 28 GHz for the millimeter-wave dual circularly polarized multi-beam antenna provided in an embodiment of the present invention; Figure 14 A simulation diagram of the axial ratio of the left-hand circularly polarized port of the millimeter-wave dual circularly polarized multi-beam antenna provided by an embodiment of the present invention when scanning different angles; Figure 15 A simulation diagram of the axial ratio of the right-hand circularly polarized port of the millimeter-wave dual circularly polarized multi-beam antenna provided by an embodiment of the present invention when scanning different angles; Markings in the figure: 1, 3D printed dielectric polarization grating lens; 1-1, lens holder; 1-2, lower lens; 1-3, upper lens; 2, millimeter wave dual-linear polarization antenna array; 2-1, first metal surface; 2-2, first dielectric substrate; 2-3, second metal surface; 2-3-1, FSIW resonant cavity middle layer; 2-3-1-1, rectangular gap; 2-3-1-2, feed stripline; 2-4, second dielectric substrate; 2-5, third dielectric substrate; 2 -6, third metal surface; 2-6-1, T-shaped radiation gap; 2-7, fourth dielectric substrate; 2-8, fifth dielectric substrate; 2-9, fourth metal surface; 2-9-1-radiation patch; 2-9-1-1, first sub-radiation patch; 2-9-1-2, second sub-radiation patch; 2-9-1-3, third sub-radiation patch; 2-10, first metal hole; 2-11, second metal hole; 2-12, third metal hole; 2-13, fourth metal hole. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with specific examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention, but are not intended to limit the present invention.

[0025] To achieve broadband, high isolation, and wide-angle dual circular polarization beam scanning, at least one embodiment provides a broadband, high isolation, millimeter-wave dual circular polarization multi-beam antenna based on a 3D-printed medium polarization grating lens 1, see Figure 1 , including a 3D-printed medium polarization grating lens 1 that realizes the dual-linear polarization to dual-circular polarization function, and a millimeter-wave dual-linear polarization antenna array 2 located directly below the 3D-printed medium polarization grating lens 1, with a first gap between the millimeter-wave dual-linear polarization antenna array 2 and the 3D-printed medium polarization grating lens 1. The millimeter-wave dual-linear polarization antenna array 2 uses a folded medium integrated waveguide structure for feeding to achieve high isolation. By adding metal through-holes and etched gaps in the resonant cavity, multi-mode resonance is achieved, effectively expanding the antenna bandwidth. The 3D-printed medium polarization grating lens 1 adopts a cylindrical Luneburg lens structure, constructing a polarization grating lens with a dielectric spindle as a unit. While improving the gain of the feeding antenna unit, it converts dual-linear polarization waves into dual-circular polarization waves. At the same time, a phase compensation structure is designed to maintain the phase difference between the horizontal and vertical components of the 45° polarized electromagnetic wave close to 90° when adjusting the lens size, thereby stabilizing the 3dB axial ratio bandwidth. The millimeter-wave dual circularly polarized multi-beam antenna array loaded with a dielectric polarization grating lens has a -10dB impedance bandwidth of 14.8%, an isolation of >35dB, a beam scanning range of ±45°, a maximum gain of 22.4dBic, and an axial ratio of less than 3dB within the scanning range.

[0026] In one embodiment, the millimeter wave dual linear polarization antenna array 2 is located on the horizontal focal plane of the 3D printed medium polarization grating lens 1. Figure 2-3 The millimeter-wave dual-linear polarization antenna array 2 is composed of 6 millimeter-wave dual-linear polarization antenna units fed by FSIW resonant cavities arranged in a 1×6 array plane, parallel to the 3D-printed medium polarization grating lens 1, and the centers of all millimeter-wave dual-linear polarization antenna units fed by FSIW resonant cavities are located on the same straight line; there is a second gap between adjacent millimeter-wave dual-linear polarization antenna units fed by FSIW resonant cavities, and the second gap Dant is 10 mm.

[0027] like Figure 4 The millimeter-wave dual-linear polarization antenna unit includes, from bottom to top, a first metal surface 2-1, a first dielectric substrate 2-2, a second metal surface 2-3, a second dielectric substrate 2-4, a third dielectric substrate 2-5, a third metal surface 2-6, a fourth dielectric substrate 2-7, a fifth dielectric substrate 2-8, a fourth metal surface 2-9, a radiation patch 2-9-1, and a plurality of first metal holes 2-10, a plurality of second metal holes 2-11, at least one third metal hole 2-12, and a plurality of fourth metal holes 2-13; the first metal holes 2-10 all pass through the first metal surface 2-1, the first dielectric substrate 2-2, the second dielectric substrate 2-4, the third dielectric substrate 2-5, and the third metal surface 2-6; the second metal holes 2-11 and the third metal holes 2-12 all pass through the first metal surface 2-1, the first dielectric substrate 2-2, the second metal surface 2-3, the second dielectric substrate 2-4, the third dielectric substrate 2-5, and the third metal surface 2-6. The fourth metal hole 2-13 penetrates the fifth dielectric substrate 2-8 and the fourth metal surface 2-9. The plurality of first metal holes 2-10, the first metal surface 2-1, the first dielectric substrate 2-2, the second metal surface 2-3, the second dielectric substrate 2-4, the third dielectric substrate 2-5, and the third metal surface 2-6 form two back-to-back FSIW resonant cavities, each having a feeding port channel. Furthermore, the second dielectric substrate 2-4 is arranged between the first dielectric substrate 2-2 and the third dielectric substrate 2-5 as an adhesive layer; the first dielectric substrate 2-2 adopts RO4003C, with a dielectric constant of 3.38, a loss tangent of 0.0027, and a thickness of 0.305 mm; the second dielectric substrate 2-4 adopts Roger 4450F, with a dielectric constant of 3.52, a loss tangent of 0.004, and a thickness of 0.1 mm; the third dielectric substrate 2-5 adopts RO4003C, with a thickness of 0.203 mm.

[0028] Furthermore, the fourth dielectric substrate 2-7 is provided between the third dielectric substrate 2-5 and the fifth dielectric substrate 2-8 as an adhesive layer; the fourth dielectric substrate 2-7 is made of Roger 4450F with a thickness of 0.1 mm; the fifth dielectric substrate 2-8 is made of RO4003C with a thickness of 0.813 mm; Furthermore, the first metal surface 2-1 is located on the back side of the first dielectric substrate 2-2; Furthermore, the second metal surface 2-3 is located between the first dielectric substrate 2-2 and the second dielectric substrate 2-4, and is the middle metal layer of the FSIW resonant cavity; see the attached Figure 5 The second metal surface 2-3 includes two FSIW resonant cavity intermediate layers 2-3-1 that are orthogonally distributed, and a third gap exists between the two FSIW resonant cavity intermediate layers 2-3-1; the two FSIW resonant cavity intermediate layers 2-3-1 have the same structure, both of which are rectangular metal sheets with a rectangular slit 2-3-1-1 and a rectangular notch on one of the outer edges, and a feeding stripline 2-3-1-2 connected to the rectangular metal sheet is provided in the rectangular notch, and the feeding stripline 2-3-1-2 is located in the feeding port channel of the FSIW resonant cavity; the feeding striplines 2-3-1-2 of the two FSIW resonant cavity intermediate layers 2-3-1 are orthogonally distributed. The two FSIW resonant cavity intermediate layers 2-3-1 are respectively located in two back-to-back FSIW resonant cavities; a plurality of second metal holes 2-11 are provided on the edge of each FSIW resonant cavity intermediate layer 2-3-1, and at least one third metal hole 2-12 is provided inside the intermediate layer; the two FSIW resonant cavities formed by the plurality of second metal holes 2-11, the first metal surface 2-1, the first dielectric substrate 2-2, the second metal surface 2-3, the second dielectric substrate 2-4, the third dielectric substrate 2-5, and the third metal surface 2-6 are orthogonal to each other.

[0029] Furthermore, the third metal surface 2-6 is located between the third dielectric substrate 2-5 and the fourth dielectric substrate 2-7, and is the metal ground of the FSIW resonant cavity; the third metal surface 2-6 is provided with a T-shaped radiation slot 2-6-1 for antenna coupling and feeding.

[0030] Furthermore, the fourth metal surface 2-9 has a notch formed therein, with a radiating patch 2-9-1 positioned within the notch, and a distance between the radiating patch 2-9-1 and the fourth metal surface 2-9. A plurality of fourth metal holes 2-13 are arranged around the notch of the fourth metal surface 2-9. The plurality of fourth metal holes 2-13 surround the radiating patch 2-9-1, thereby limiting surface wave propagation on the substrate, reducing mutual coupling between ports, and maintaining a stable radiation pattern.

[0031] As an example, the radiation patch 2-9-1 is an axisymmetric structure, which includes at least one first sub-radiation patch 2-9-1-1, at least one second sub-radiation patch 2-9-1-2 and at least one third sub-radiation patch 2-9-1-3, and there is a gap between adjacent sub-radiation patches. Figure 6In this embodiment, the radiating patch 2-9-1 is provided in a rectangular structure consisting of four first sub-radiating patches 2-9-1-1, four second sub-radiating patches 2-9-1-2, and eight third sub-radiating patches 2-9-1-3. The four first sub-radiating patches 2-9-1-1 are arranged in a 2×2 pattern to form a rectangular structure. The four second sub-radiating patches 2-9-1-2 are respectively distributed at the four corners of the rectangular structure formed by the four first sub-radiating patches 2-9-1-1. Two third sub-radiating patches 2-9-1-3 are arranged between two adjacent second sub-radiating patches 2-9-1-2. The sub-radiating patches are equally spaced, and all four corners of the sub-radiating patches are chamfered, which reduces the unit size of the antenna.

[0032] Furthermore, the rectangular gap 2-3-1-1 is located in the mode TE 1.5,0,1 The current path can be extended by cutting the current, thereby reducing the mode TE 1.5,0,1 The resonant frequency of the mode TE is affected by adjusting the distance between the rectangular gap 2-3-1-1 and the second metal hole 2-11. 1.5,0,1 resonant frequency.

[0033] Furthermore, the third metal hole 2-12 is located in the mode TE 0.5,0,1 By perturbing the electric field distribution and adjusting the distance between the third metal hole 2-12 and the second metal hole 2-11, the control mode TE is realized. 0.5,0,1 resonant frequency.

[0034] like Figure 3 As shown, the millimeter-wave dual-linear polarization antenna array 2 described in this embodiment has 12 feeding ports, the odd-numbered ports correspond to left-hand circularly polarized waves in six directions, and the even-numbered ports correspond to right-hand circularly polarized waves in six directions.

[0035] One implementation method is shown in the attached Figure 7 The 3D-printed dielectric polarization grating lens 1 is cylindrical. It comprises a lens holder 1-1, a lower lens 1-2, and an upper lens 1-3. Both the lower lens 1-2 and the upper lens 1-3 have multiple layers, each comprising a main dielectric spindle unit and n sub-dielectric spindle units, where n>1, extending through the main dielectric spindle unit. Air layers exist between adjacent sub-dielectric spindle units. The n sub-dielectric spindle units gradually decrease in size along the axis of the main dielectric spindle unit, conforming to the equivalent refractive index distribution of a Luneburg lens. The lower lens 1-2 has more layers than the upper lens 1-3. The dielectric spindle units in each layer of the lower lens 1-2 and the upper lens 1-3 differ in their principal axis and arrangement directions, but remain identical in number, shape, and size.

[0036] As an example, Figure 7-10 As shown, the lower lens 1-2 has nine layers, and the upper lens 1-3 has four layers, with a diameter of 72 mm. The dielectric spindle units of the lower lens 1-2 have their main axes oriented in the longitudinal direction (i.e., the y-axis) and are arranged horizontally along the horizontal direction (i.e., the x-axis). The dielectric spindle units of the upper lens 1-3 have their main axes oriented in the horizontal direction (i.e., the x-axis) and are arranged horizontally along the longitudinal direction (i.e., the y-axis). Each layer of the upper lens 1-3 and the lower lens 1-2 has 27 dielectric spindle units: a main dielectric spindle unit and 26 sub-dielectric spindle units arranged from the inside out, with air spaces between adjacent sub-dielectric spindle units. The 26 sub-dielectric spindle units are symmetrical about the main axis of the main dielectric spindle unit and gradually decrease in size along the arrangement direction, conforming to the refractive index distribution equivalent to a Luneburg lens.

[0037] The 3D-printed medium polarization grating lens 1 is constructed from a main medium spindle unit and multiple sub-medium spindle units. It has different dielectric constants for the 0° and 90° components of a 45° polarized incident wave. The different dielectric constants cause a phase difference between the two mutually orthogonal components, achieving conversion from linearly polarized waves to circularly polarized waves. The arrangement direction of the medium spindle units in each layer of the upper lenses 1-3 is orthogonal to the lower lenses 1-2. As a phase compensation structure of the entire lens, the phase difference generated when the electromagnetic wave penetrates the upper lenses 1-3 will be reversed and reduced, and the phase difference after passing through the lens is ultimately maintained at approximately 90°. The 3D-printed medium polarization grating lens 1 can flexibly adjust the linear polarization-circular polarization conversion bandwidth by controlling the ratio of medium to air and height parameters, converting ±45° linearly polarized waves into left-handed circularly polarized waves and right-handed circularly polarized waves.

[0038] The lens bracket 1-1 is made of resin material with a thickness of 1mm and is used to support the overall structure of the lens; as shown in the figure, both ends of the main medium spindle unit and the sub-medium spindle unit of each layer are connected to the lens bracket 1-1.

[0039] The spacing between each layer of the lower lens 1-2 and the upper lens 1-3 is equal, and there is a gap.

[0040] The main medium spindle unit and the daughter medium spindle unit have the same structure, shape and material. The medium spindle unit is used below to represent the main medium spindle unit and the daughter medium spindle unit.

[0041] The dielectric constant of each layer of the dielectric spindle unit Satisfies the following formula: Formula (1) Where r represents the distance between the sub-medium spindle unit and the center of the main medium spindle unit, and D represents the diameter of the 3D printing medium polarization grating lens 1; like Figure 8 and Figure 9 As shown, the medium spindle unit is a spindle structure, and the radius r is a function of the y-axis coordinate position, satisfying the following formula: Formula (2) in are the dielectric constants of the dielectric spindle material and the air layer between adjacent sub-dielectric spindle units, respectively; H represents the height of a dielectric spindle unit including an air layer, represents the distance from the center of the main medium spindle unit in the x-axis direction, and y represents the distance from the center of the main medium spindle unit in the y-axis direction.

[0042] The dielectric constant of the position where the medium spindle unit is located According to the A_BG formula: Formula (3) in are the dielectric spindle material, the position of the dielectric spindle unit, and the dielectric constant of the air layer between adjacent sub-dielectric spindle units, respectively. P is the volume fraction of the dielectric spindle unit. like Figure 9 As shown, with Δ x The dielectric constant variation function of the cutting position also changes with the change of H Δ x , obtaining a medium spindle unit whose width and height are parallel to the y-axis direction.

[0043] Figure 11 The reflection coefficient diagram of the FSIW resonant cavity-fed millimeter-wave dual-polarization antenna unit 3 of the present invention is described. It can be seen from the diagram that the -10dB impedance bandwidth of the antenna unit covers 25.8-29.8GHz, and the port isolation of the antenna unit is greater than 35dB.

[0044] Figure 12 The simulated radiation pattern of the odd-numbered ports of the broadband high-isolation millimeter-wave dual-circularly polarized multi-beam antenna of the present invention at 28 GHz for left-hand circularly polarized beam scanning is shown. It can be seen that within the 3 dB gain variation scanning range, the beam scanning range reaches ±45°.

[0045] Figure 13 The simulated radiation pattern of the even-numbered ports of the broadband high-isolation millimeter-wave dual-circularly polarized multi-beam antenna of the present invention at 28 GHz for right-hand circularly polarized beam scanning is shown. It can be seen that within the 3 dB gain variation scanning range, the beam scanning range reaches ±45°.

[0046] Figure 14The circular polarization axial ratio simulation diagram of the odd-numbered ports of the broadband high-isolation millimeter-wave dual circularly polarized multi-beam antenna of the present invention is shown when the beam is scanned at different angles at 28 GHz. It can be seen that within the beam scanning range, the axial ratio is less than 3 dB.

[0047] Figure 15 The circular polarization axial ratio simulation diagram of the odd-numbered ports of the broadband high-isolation millimeter-wave dual circularly polarized multi-beam antenna of the present invention is shown when the beam is scanned at different angles at 28 GHz. It can be seen that within the beam scanning range, the axial ratio is less than 3 dB.

[0048] The above description is merely a preferred embodiment of the present invention and does not limit the embodiments of the present invention. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications shall be included within the scope of protection of the claims of the present invention.

Claims

1. A broadband high-isolation millimeter-wave dual circularly polarized multi-beam antenna, characterized in that The invention comprises a 3D printed medium polarization grating lens (1), and a millimeter wave dual-linear polarization antenna array (2) located directly below the 3D printed medium polarization grating lens (1), wherein a first gap exists between the millimeter wave dual-linear polarization antenna array (2) and the 3D printed medium polarization grating lens (1); The millimeter wave dual-linear polarization antenna array (2) is located on the horizontal focal plane of the 3D printed medium polarization grating lens (1); the millimeter wave dual-linear polarization antenna array (2) is formed by a planar arrangement of a plurality of millimeter wave dual-linear polarization antenna units fed by FSIW resonant cavities, is parallel to the 3D printed medium polarization grating lens (1), and the centers of all millimeter wave dual-linear polarization antenna units fed by FSIW resonant cavities are located on the same straight line; a second gap exists between adjacent millimeter wave dual-linear polarization antenna units fed by FSIW resonant cavities; The 3D printed medium polarization grating lens (1) comprises a lens holder (1-1), a lower lens (1-2) and an upper lens (1-3); the lower lens (1-2) and the upper lens (1-3) both have multiple layers, and each layer comprises a main medium spindle unit and n sub-medium spindle units whose centers pass through the main medium spindle unit, n>1, and air layers exist between adjacent sub-medium spindle units; the n sub-medium spindle units have a trend of gradually decreasing in size along the axial direction of the main medium spindle unit, conforming to the refractive index distribution equivalent to that of a Luneburg lens; The medium spindle units of each layer of the lower lens (1-2) and the medium spindle units of each layer of the upper lens (1-3) are different in main axis direction and arrangement direction, but the number, shape and size of the medium spindle units are the same.

2. The broadband high-isolation millimeter-wave dual circularly polarized multi-beam antenna according to claim 1, characterized in that: The number of layers of the lower lens (1-2) is greater than that of the upper lens (1-3).

3. The broadband high-isolation millimeter-wave dual circularly polarized multi-beam antenna according to claim 1, characterized in that: The main axis of the medium spindle unit of the lower lens (1-2) points to the longitudinal direction and is arranged transversely along the horizontal direction, while the main axis of the medium spindle unit of the upper lens (1-3) points to the horizontal direction and is arranged transversely along the longitudinal direction.

4. The broadband high-isolation millimeter-wave dual circularly polarized multi-beam antenna according to claim 1, characterized in that: The 3D printing medium polarization grating lens (1) is cylindrical.

5. The broadband high-isolation millimeter-wave dual circularly polarized multi-beam antenna according to claim 1, characterized in that: The millimeter wave dual-linear polarization antenna unit includes, from bottom to top, a first metal surface (2-1), a first dielectric substrate (2-2), a second metal surface (2-3), a second dielectric substrate (2-4), a third dielectric substrate (2-5), a third metal surface (2-6), a fourth dielectric substrate (2-7), a fifth dielectric substrate (2-8), a fourth metal surface (2-9), and a plurality of first metal holes (2-10), a plurality of second metal holes (2-11), at least one third metal hole (2-12), and a plurality of fourth metal holes (2-13); the first metal holes (2-10) all pass through the first metal surface (2-1), the first dielectric substrate (2-2), the second dielectric substrate (2-4), the third dielectric substrate (2-5), the third metal surface ( 2-6); the second metal hole (2-11) and the third metal hole (2-12) both penetrate the first metal surface (2-1), the first dielectric substrate (2-2), the second metal surface (2-3), the second dielectric substrate (2-4), the third dielectric substrate (2-5), and the third metal surface (2-6); the fourth metal hole (2-13) penetrates the fifth dielectric substrate (2-8) and the fourth metal surface (2-9); and the plurality of first metal holes (2-10), the first metal surface (2-1), the first dielectric substrate (2-2), the second metal surface (2-3), the second dielectric substrate (2-4), the third dielectric substrate (2-5), and the third metal surface (2-6) form two back-to-back FSIW resonant cavities, each having a feeding port and being orthogonal to each other.

6. The broadband high-isolation millimeter-wave dual circularly polarized multi-beam antenna according to claim 1, characterized in that: The second dielectric substrate (2-4) is arranged between the first dielectric substrate (2-2) and the third dielectric substrate (2-5); the fourth dielectric substrate (2-7) is arranged between the third dielectric substrate (2-5) and the fifth dielectric substrate (2-8); the first metal surface (2-1) is located on the back of the first dielectric substrate (2-2); The second metal surface (2-3) is located between the first dielectric substrate (2-2) and the second dielectric substrate (2-4), and is the middle metal layer of the FSIW resonant cavity; the second metal surface (2-3) includes two FSIW resonant cavity middle layers that are orthogonally distributed, and a third gap exists between the two FSIW resonant cavity middle layers; the two FSIW resonant cavity middle layers have the same structure, both of which are rectangular metal sheets with a rectangular gap (2-3-1-1) and a rectangular notch on one of the outer edges, and a feeding stripline (2-3-1-2) connected to the rectangular metal sheet is provided in the rectangular notch; the feeding striplines (2-3-1-2) of the two FSIW resonant cavity middle layers are orthogonally distributed; the two FSIW resonant cavity middle layers are respectively located in two back-to-back FSIW resonant cavities; a plurality of second metal holes (2-11) are provided on the edge of each FSIW resonant cavity middle layer, and at least one third metal hole (2-12) is provided inside the layer; The third metal surface (2-6) is located between the third dielectric substrate (2-5) and the fourth dielectric substrate (2-7) and serves as the metal ground of the FSIW resonant cavity; the third metal surface (2-6) is provided with a T-shaped radiation slot for antenna coupling and feeding; A notch is formed in the fourth metal surface (2-9), a radiation patch (2-9-1) is arranged in the notch, and a distance exists between the radiation patch (2-9-1) and the fourth metal surface (2-9); a plurality of fourth metal holes (2-13) are arranged around the notch of the fourth metal surface (2-9).

7. The broadband high-isolation millimeter-wave dual circularly polarized multi-beam antenna according to claim 1, characterized in that: By adjusting the distance between the third metal hole (2-12) and the second metal hole (2-11), the control mode TE is realized. 0.5,0,1 The resonant frequency of the mode TE is affected by adjusting the distance between the rectangular gap (2-3-1-1) and the second metal hole (2-11). 1.5,0,1 resonant frequency.

8. The broadband high-isolation millimeter-wave dual circularly polarized multi-beam antenna according to claim 1, characterized in that: The radiation patch (2-9-1) is an axisymmetric structure, which includes at least one first sub-radiation patch (2-9-1-1), at least one second sub-radiation patch (2-9-1-2) and at least one third sub-radiation patch (2-9-1-3), and there is a gap between adjacent sub-radiation patches.

9. The broadband high-isolation millimeter-wave dual circularly polarized multi-beam antenna according to claim 1, characterized in that: The dielectric constants of the main dielectric spindle unit and the sub-dielectric spindle unit of each layer All satisfy the following formula: Formula (1) Where r represents the distance between the sub-medium spindle unit and the center of the main medium spindle unit, and D represents the diameter of the 3D printing medium polarization grid lens (1).

10. The broadband high-isolation millimeter-wave dual circularly polarized multi-beam antenna according to claim 1, characterized in that: The radius r of the main dielectric spindle unit and the daughter dielectric spindle unit is a function of the y-axis coordinate position and satisfies the following formula: Formula (2) in are the dielectric constants of the dielectric spindle material and the air layer between adjacent sub-dielectric spindle units, respectively; H represents the height of a dielectric spindle unit including an air layer, represents the distance from the center of the main medium spindle unit in the x-axis direction, and y represents the distance from the center of the main medium spindle unit in the y-axis direction.

Images