Broadband Wide-Angle Scanning Circularly Polarized Millimeter-Wave Phased Array Antenna Element and Array

Abstract

The invention relates to the technical field of circularly polarized phased array antennas, and provides a wide bandwidth angle scanning circularly polarized millimeter wave phased array antenna unit and an array; the antenna unit comprises: a first dielectric layer, a second dielectric layer and a third dielectric layer which are stacked in sequence; a radiation patch is arranged on a side of the first dielectric layer away from the second dielectric layer, and the radiation patch is a circular microstrip patch; a first metal layer is sandwiched between the first dielectric layer and the second dielectric layer, two coupling slots symmetrical about a rotation center and a plurality of isolation slots arranged around the periphery of the two coupling slots are opened on the first metal layer, the rotation center coincides with the center of the radiation patch in the stacking direction, and one end of each coupling slot has a first arc slot bent toward one side, and the other end has a second arc slot bent toward the opposite other side; a feeding microstrip is sandwiched between the second dielectric layer and the third dielectric layer, and the feeding microstrip is used for coupling and feeding the radiation patch through the two coupling slots.

Description

Technical Field

[0001] The present invention relates to the technical field of circularly polarized phased array antennas, and in particular to a wide bandwidth angle scanning circularly polarized millimeter wave phased array antenna unit and an array. Background Art

[0002] Millimeter-wave wide-bandwidth and wide-angle scanning circularly polarized phased array antennas are the first choice for 6G network feed links. In recent years, the use of dual-linear polarization to form circular polarization is a typical solution for realizing wide-angle scanning circularly polarized phased arrays.

[0003] However, dual-line circular polarization usually uses dual-point feeding, which requires an additional larger feeding network, resulting in an exponential increase in the number of system channels under the same antenna scale, increasing the complexity of the system, and one antenna unit corresponds to two polarizations, each polarization corresponds to a power division system, which increases the difficulty of system design. As the frequency increases, the spatial layout is limited, which also increases the difficulty of wiring. At the same time, in the process of synthesizing dual-line polarization into circular polarization, not only the phase difference of each linear polarization must be adjusted to meet the requirements, but also the amplitude of each linear polarization must be adjusted to be equal, which may cause unnecessary losses and reduce the efficiency of the system. Moreover, since each antenna must be weighted in amplitude and phase, the workload and difficulty of antenna debugging are greatly increased. In addition, the existing circularly polarized antennas form a phased array, and the sub-array spacing is close to or exceeds the wavelength of the antenna, resulting in a smaller scanning angle range of the phased array. Summary of the invention

[0004] The present invention provides a wide bandwidth angular scanning circularly polarized millimeter wave phased array antenna unit and array, which are used to solve the defects in the prior art that when circularly polarized antennas form a wide bandwidth angular scanning phased array, the system complexity is high, the design difficulty is great, the wiring difficulty is great, the antenna debugging workload and difficulty are large, the system efficiency may be reduced, and the scanning angle range of the phased array becomes smaller.

[0005] The present invention provides a wide bandwidth angle scanning circular polarization millimeter wave phased array antenna unit, comprising: a first dielectric layer, a second dielectric layer and a third dielectric layer which are stacked in sequence;

[0006] A radiation patch, arranged on a side of the first dielectric layer away from the second dielectric layer, the radiation patch being a circular microstrip patch;

[0007] A first metal layer is sandwiched between the first dielectric layer and the second dielectric layer, two coupling slots and a plurality of isolation slots are provided on the first metal layer, the two coupling slots are arranged to be rotationally symmetrical about a rotation center, the rotation center coincides with the center of the radiation patch in the stacking direction, and one end of each coupling slot has a first arc slot bent toward one side, and the other end has a second arc slot bent toward the opposite other side, so as to excite two electromagnetic modes perpendicular to each other, and the plurality of isolation slots are arranged around the periphery of the two coupling slots;

[0008] A feeding microstrip, sandwiched between the second dielectric layer and the third dielectric layer, the feeding microstrip comprising a connecting portion and a feeding portion, the feeding portion being arranged corresponding to the two coupling slots, and being used for coupling and feeding the radiation patch through the two coupling slots;

[0009] The second metal layer is attached to a side of the third dielectric layer away from the second dielectric layer. The second metal layer is provided with a coaxial feeding point, and the coaxial feeding point is electrically connected to the connecting portion.

[0010] According to the wide bandwidth angular scanning circularly polarized millimeter wave phased array antenna unit provided by the present invention, the length of the first arc gap is associated with the antenna reflection coefficient of the wide bandwidth angular scanning circularly polarized millimeter wave phased array antenna unit; the length of the second arc gap is associated with the position of the antenna axis ratio resonance point of the wide bandwidth angular scanning circularly polarized millimeter wave phased array antenna unit.

[0011] According to the wide bandwidth angle scanning circularly polarized millimeter wave phased array antenna unit provided by the present invention, the coupling slot also has a middle slot, the first arc slot is connected to one end of the middle slot, and the second arc slot is connected to the other end of the middle slot; the two coupling slots divide the first metal stratum into a middle area and a peripheral area, and the middle area is located between the two coupling slots; the feeding part includes a first feeding branch node and a second feeding branch node, and the first feeding branch node and the second feeding branch node are connected to opposite sides of one end of the connecting part; the connecting part is The projection of the first metal stratum is located between the two coupling slots, the projection of the first feed branch node on the first metal stratum vertically intersects the middle slot of one coupling slot, and the projection of the second feed branch node on the first metal stratum vertically intersects the middle slot of another coupling slot; and the difference between the length of the projection of the first feed branch node on the first metal stratum located in the middle area and the length of the projection of the second feed branch node on the first metal stratum located in the middle area is half a medium wavelength.

[0012] According to the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element provided by the present invention, the coupling slot is divided into a first section and a second section along the length direction, and the boundary line between the first section and the second section is the projection of the center line of the first feeding stub or the second feeding stub on the first metal ground plane; the position of the boundary line is associated with the antenna reflection coefficient of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element.

[0013] According to the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element provided by the present invention, both the first feeding stub and the second feeding stub include end stub portions whose projections on the first metal ground plane are located in the peripheral region, the lengths of the two end stub portions are equal, and the length of the end stub portion is associated with the antenna reflection coefficient of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element.

[0014] According to the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element provided by the present invention, the dielectric constant of the second dielectric layer is greater than the dielectric constants of the first dielectric layer and the third dielectric layer.

[0015] According to the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element provided by the present invention, the first dielectric layer, the second dielectric layer, and the third dielectric layer are all millimeter-wave radio frequency boards.

[0016] According to the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element provided by the present invention, a plurality of metal vias are provided on both the second dielectric layer and the third dielectric layer, the plurality of metal vias are all connected to the first metal ground plane and the second metal ground plane, and the plurality of metal vias are arranged around the outer contour of the feeding microstrip and the coupling slot to enclose the feeding microstrip and the coupling slot within the range enclosed by the plurality of metal vias.

[0017] According to the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element provided by the present invention, the plurality of metal vias near the coaxial feeding point are arranged around a part of the outer circumference of the coaxial feeding point.

[0018] According to the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element provided by the present invention, the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element further includes an adhesive layer, the adhesive layer is sandwiched between the first dielectric layer and the first metal ground plane and between the second dielectric layer and the third dielectric layer; the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element is made by a multi-layer PCB co-pressing process.

[0019] The present invention also provides a broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna array, including the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element described in any one of the above.

[0020] The broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element and array provided by the present invention adopt single-point feeding. The circularly polarized antenna structure of single-point feeding is the simplest, without an additional feeding network, effectively reducing the complexity of the system. Moreover, single-point feeding has the advantage of low profile, saving space, reducing the difficulty of wiring, having a simple structure and being easy to implement, effectively reducing the difficulty of system design and cost. By setting a double inverted S-shaped coupling slot to couple-feed the radiation patch, two mutually perpendicular electromagnetic modes can be excited to realize circular polarization formed by dual linear polarizations, which not only expands the operating frequency bandwidth but also broadens the circular polarization axial ratio bandwidth, avoiding the defect of narrow operating bandwidth of the circularly polarized antenna with single-point feeding. At the same time, by setting the circular radiation patch and the double inverted S-shaped coupling slot to be symmetric about the center of the circle, the antenna element structure has very good circular polarization symmetry, so as to obtain a radiation pattern and an axial ratio pattern with good rotational symmetry in space, which is beneficial to the optimization of the antenna array design, without the need to laboriously adjust the phase and amplitude of the linear polarization, avoiding reducing the system efficiency, effectively reducing the workload and difficulty of antenna debugging, and also effectively avoiding the reduction of the scanning angle range of the phased array after arraying, realizing a circularly polarized antenna with broadband wide-angle beam characteristics. By setting isolation slots, the isolation performance of the antenna element can be improved and leakage can be reduced. When using the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element of the present invention to form a circularly polarized phased array antenna array, the mutual coupling between array elements can be effectively reduced, and a millimeter-wave circularly polarized phased array with wide-angle scanning can be realized.

[0021] The broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element of the present invention realizes a circularly polarized antenna with broadband wide-angle beam characteristics by adopting single-point feeding combined with an antenna element structure with very good circular polarization symmetry, solving the defects in the prior art that when circularly polarized antennas form a broadband wide-angle scanning phased array, the system complexity is high, the design difficulty is large, the wiring difficulty is large, the workload and difficulty of antenna debugging are large, the system efficiency may be reduced, and the scanning angle range of the phased array becomes smaller. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0023] Figure 1 It is a schematic diagram of the stacked structure of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element provided by an embodiment of the present invention;

[0024] Figure 2It is the top view of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element provided by the embodiment of the present invention;

[0025] Figure 3 It is the structural schematic diagram of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna array provided by the embodiment of the present invention;

[0026] Figure 4 It is the reflection coefficient curve graph of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element and the array element;

[0027] Figure 5 It is the axial ratio curve graph of the maximum radiation direction of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element and the array element;

[0028] Figure 6 It is the radiation pattern of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element provided by the embodiment of the present invention;

[0029] Figure 7 It is the axial ratio pattern of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element provided by the embodiment of the present invention;

[0030] Figure 8 It is the radiation pattern of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna array element provided by the embodiment of the present invention;

[0031] Figure 9 It is the axial ratio pattern of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna array element provided by the embodiment of the present invention.

[0032] Reference numerals:

[0033] 100: Broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element;

[0034] 1: First dielectric layer; 2: Second dielectric layer; 3: Third dielectric layer; 4: Radiation patch; 5: First metal ground layer; 6: Feeding microstrip; 7: Second metal ground layer; 8: Metal through hole; 9: Adhesive layer;

[0035] 51: Coupling slot; 511: First arc slot; 512: Second arc slot; 513: First section; 514: Second section; 515: Demarcation line; 516: Middle section slot; 52: Isolation slot; 61: Connection part; 62: Feeding part; 621: First feeding branch; 622: Second feeding branch; 623: End branch part; 71: Coaxial feeding point. Detailed implementation manners

[0036] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts belong to the scope of protection of the present invention.

[0037] It should be noted that expressions such as "vertical direction", "horizontal direction", "+45° or -45° direction", "upper", "middle", "lower", and the like are for illustrative purposes only, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0038] In the present invention, unless otherwise clearly defined and limited, terms such as "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or communicable with each other; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] The following will describe Figures 1 - 3 the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna unit and array of the present invention.

[0040] As Figure 1 and Figure 2 shown, the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna unit 100 provided by the present invention includes a first dielectric layer 1, a second dielectric layer 2, a third dielectric layer 3, a radiation patch 4, a first metal ground layer 5, a feeding microstrip 6, and a second metal ground layer 7.

[0041] Among them, the first dielectric layer 1, the second dielectric layer 2, and the third dielectric layer 3 are stacked in sequence. The radiation patch 4 is disposed on the side of the first dielectric layer 1 away from the second dielectric layer 2, and the radiation patch 4 is a circular microstrip patch. The first metal ground layer 5 is sandwiched between the first dielectric layer 1 and the second dielectric layer 2. Two coupling slits 51 and multiple isolation slits 52 are formed on the first metal ground layer 5. The two coupling slits 51 are arranged to be rotationally symmetric about the rotation center, and the rotation center coincides with the center of the radiation patch 4 in the stacking direction. One end of each coupling slit 51 has a first arc slit 511 bent toward one side, and the other end has a second arc slit 512 bent toward the opposite side to excite two mutually perpendicular electromagnetic modes. The multiple isolation slits 52 are arranged around the outer periphery of the two coupling slits 51. The feeding microstrip 6 is sandwiched between the second dielectric layer 2 and the third dielectric layer 3. The feeding microstrip 6 includes a connecting portion 61 and a feeding portion 62. The feeding portion 62 is arranged corresponding to the two coupling slits 51 to couple and feed the radiation patch 4 through the two coupling slits 51. The second metal ground layer 7 is attached to the side of the third dielectric layer 3 away from the second dielectric layer 2. The second metal ground layer 7 is provided with a coaxial feeding point 71, and the coaxial feeding point 71 is electrically connected to the connecting portion 61 of the feeding microstrip 6.

[0042] Among them, the two coupling slits 51 being rotationally symmetric about the rotation center means that the structures of the two coupling slits 51 are the same, are arranged centrosymmetrically with respect to the rotation center, and the two coupling slits 51 can be rotated around the rotation center to coincide. The stacking direction refers to the direction in which the first dielectric layer 1, the second dielectric layer 2, and the third dielectric layer 3 are stacked in sequence.

[0043] The circularly polarized phased array antenna uses a large-scale antenna array and flexible beamforming technology to dynamically generate a series of highly directive beams, greatly improving the efficiency of spatial multiplexing. At the same time, the circular polarization characteristic of the phased array compensates for the influence of the polarization rotation effect of electromagnetic waves penetrating the ionosphere on the radio waves. Using a circularly polarized antenna with broadband and wide-angle scanning performance to form a phased array is the key technology for realizing a mobile satellite communication system.

[0044] In this embodiment, the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100 (hereinafter referred to as the antenna element) is integrated on a multi-layer dielectric, and the radiation patch 4 is used to radiate electromagnetic signals outward; a coupling slot 51 is formed on the first metal ground layer 5, and the coupling slot 51 is used to couple radio frequency signals to the radiation patch 4; the feeding part 62 of the feeding microstrip 6 is arranged corresponding to the two coupling slots 51, so as to couple and feed the radiation patch 4 through the two coupling slots 51; the second metal ground layer 7 is provided with a coaxial feeding point 71, and the coaxial feeding point 71 is electrically connected to the connecting part 61 of the feeding microstrip 6, and radio frequency signals are transmitted to the feeding microstrip 6 through the coaxial feeding point 71 to realize single-point feeding; thus, the radiation patch 4, the first metal ground layer 5, the feeding microstrip 6 and the second metal ground layer 7 form the main body of the antenna element. When in use, the radio frequency signal is transmitted through the feeding microstrip 6 and coupled to the radiation patch 4 to realize the external emission of the signal.

[0045] Among them, the antenna element is integrated on multiple dielectric layers (i.e., the first dielectric layer 1, the second dielectric layer 2 and the third dielectric layer 3), and can be processed by a multi-layer PCB (Printed Circuit Boards) co-pressing process, which is easy to produce and realize, and reduces costs.

[0046] The radiation patch 4 adopts a circular microstrip patch, such as a circular metal patch, which is rotationally symmetric in structure. Rotational symmetry is beneficial to the symmetry of the radiation pattern and the axial ratio pattern, so that the mutual coupling between array elements has the least influence on the pattern when the antenna element forms an antenna array.

[0047] The two ends of the coupling slot 51 are respectively provided with a first arc slot 511 and a second arc slot 512 with opposite bending directions, forming a coupling slot 51 with an overall inverted S shape. The two coupling slots 51 can excite two mutually perpendicular electromagnetic modes, which is the basis for generating circular polarization characteristics, and can expand the working frequency bandwidth and the circular polarization axial ratio bandwidth of the antenna element; specifically, the two first arc slots 511 of the two coupling slots 51 are used to generate polarization in one direction, and the two second arc slots 512 are used to generate polarization in another direction, and the two polarization directions are perpendicular to each other, constituting a two-line polarization arranged orthogonally, and then circular polarization is formed by using the two-line polarization.

[0048] The two inverted S-shaped coupling slots 51 are rotationally centrosymmetrically distributed, and the center of rotation coincides with the center of the radiation patch 4, so that the excited radiation field has better rotational symmetry in space, and the pattern excited by the antenna element has good rotational symmetry. Therefore, when the antenna element is used to form an antenna array, the consistency of the array element patterns can be guaranteed.

[0049] The double-inverted-S coupling structure and circular patch symmetric about the center of the circle enable the antenna element structure to have very good circular polarization symmetry, thereby obtaining a radiation pattern and axial ratio pattern with good rotational symmetry in space, which is beneficial to the optimization of antenna array design.

[0050] An isolation gap 52 is also formed on the first metal layer 5, and the isolation gap 52 is arranged around the two coupling gaps 51, which can cut off the coupled induced current on the first metal layer 5 between adjacent array elements when the antenna elements are grouped, reduce leakage, and thus reduce the mutual coupling between the array elements; and compared with the existing method of loading metal holes between array elements, the isolation gap 52 is simple and easy to implement. Especially in the multi-layer PCB co-pressing process, the number of co-pressing times can be reduced, making the original scheme that cannot be processed due to the number of co-pressing times become feasible. Currently, the multi-layer PCB co-pressing process cannot be processed when the number of co-pressing times exceeds 4 times.

[0051] The broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100 of the present invention, by adopting single-point feeding, the circularly polarized antenna structure of single-point feeding is the simplest, without the need for an additional feeding network, effectively reducing the complexity of the system. Moreover, single-point feeding has the advantage of low profile, saving space, reducing the difficulty of wiring, being simple and easy to implement, effectively reducing the difficulty of system design and cost; by setting the double-inverted-S coupling gap 51 to couple and feed the radiation patch 4, two mutually perpendicular electromagnetic modes can be excited to realize circular polarization formed by dual linear polarization, which not only expands the working frequency bandwidth but also broadens the circular polarization axial ratio bandwidth, avoiding the defect of the narrow working bandwidth of the circularly polarized antenna of single-point feeding; at the same time, by setting the circular radiation patch 4 and the double-inverted-S coupling gap 51 to be symmetric about the center of the circle, the antenna element structure has very good circular polarization symmetry, thereby obtaining a radiation pattern and axial ratio pattern with good rotational symmetry in space, which is beneficial to the optimization of antenna array design, without the need to laboriously adjust the phase and amplitude of the linear polarization, avoiding reducing the system efficiency, effectively reducing the workload and difficulty of antenna debugging, and also being able to effectively avoid the reduction of the scanning angle range of the phased array after arraying, realizing a circularly polarized antenna with broadband wide-angle beam characteristics; by setting the isolation gap 52, the isolation performance of the antenna element can be improved, leakage can be reduced. When the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100 of the present invention is used to form a circularly polarized phased array antenna array, the mutual coupling between the array elements can be effectively reduced, and a millimeter-wave circularly polarized phased array with wide-angle scanning can be realized.

[0052] The broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100 of the present invention realizes a circularly polarized antenna with broadband wide-angle beam characteristics by adopting single-point feeding combined with an antenna element structure with very good circular polarization symmetry, and solves the problems in the prior art that when circularly polarized antennas form a broadband wide-angle scanning phased array, the system complexity is high, the design difficulty is large, the wiring difficulty is large, the workload and difficulty of antenna debugging are large, which may reduce the system efficiency, and the scanning angle range of the phased array becomes smaller.

[0053] In a specific embodiment, the first metal ground layer 5 is a rectangular metal plate, and the isolation gap 52 is a rectangular gap; eight rectangular isolation gaps 52 are formed on the four circumferential edges of the first metal ground layer 5. Among them, the isolation gap 52 can be formed by etching.

[0054] Specifically, as Figure 1 shown, the length L1 of the first arc-shaped gap 511 is associated with the antenna reflection coefficient of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100; the length L2 of the second arc-shaped gap 512 is associated with the position of the antenna axial ratio resonance point of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100.

[0055] In this embodiment, adjusting the length L1 of the first arc-shaped gap 511 can adjust the antenna reflection coefficient, and adjusting the length L2 of the second arc-shaped gap 512 can adjust the position of the antenna axial ratio resonance point, so as to control the axial ratio bandwidth, which is beneficial to expanding the axial ratio bandwidth of the antenna.

[0056] Specifically, as Figure 1 shown, the coupling gap 51 also has a middle section gap 516. The first arc-shaped gap 511 is connected to one end of the middle section gap 516, and the second arc-shaped gap 512 is connected to the other end of the middle section gap 516, and the first arc-shaped gap 511 and the second arc-shaped gap 512 are bent towards opposite sides of the middle section gap 516 respectively; the two coupling gaps 51 divide the first metal ground layer 5 into a middle area and an outer area. The middle area is located between the two coupling gaps 51, and the outer area surrounds the outside of the two coupling gaps 51. As Figure 2As shown, the feeding part 62 of the feeding microstrip 6 includes a first feeding branch 621 and a second feeding branch 622. The first feeding branch 621 and the second feeding branch 622 are connected to opposite sides of one end of the connecting part 61, and the other end of the connecting part 61 is electrically connected to the coaxial feeding point 71. When observing the positional relationship between the feeding microstrip 6 and the two coupling slits 51 in the stacking direction, that is, the projection of the connecting part 61 on the first metal ground layer 5 is located between the two coupling slits 51. The projection of the first feeding branch 621 on the first metal ground layer 5 is perpendicularly crossed with the middle slit 516 of one coupling slit 51, and the projection of the second feeding branch 622 on the first metal ground layer 5 is perpendicularly crossed with the other coupling slit 51. And the difference between the length L3 of the projection of the first feeding branch 621 on the first metal ground layer 5 located in the middle region part and the length L4 of the projection of the second feeding branch 622 on the first metal ground layer 5 located in the middle region part is half of the dielectric wavelength.

[0057] Among them, the projection of the first feeding branch 621 on the first metal ground layer 5 being perpendicularly crossed with the middle slit 516 of one coupling slit 51 means that the projection of the first feeding branch 621 on the first metal ground layer 5 intersects with the middle slit 516 of this coupling slit 51, the intersection position is located on this middle slit 516, and the projection of the first feeding branch 621 and the part of this middle slit 516 at the intersection position are perpendicular to each other.

[0058] Similarly, the projection of the second feeding branch 622 on the first metal ground layer 5 being perpendicularly crossed with the other coupling slit 51 means that the projection of the second feeding branch 622 on the first metal ground layer 5 intersects with the middle slit 516 of this other coupling slit 51, the intersection position is located on this middle slit 516, and the projection of the second feeding branch 622 and the part of this middle slit 516 at the intersection position are perpendicular to each other.

[0059] In this embodiment, the first feeding branch 621 is arranged corresponding to one coupling slit 51. By setting the perpendicular crossing, feeding is coupled through this coupling slit 51. The second feeding branch 622 is arranged corresponding to the other coupling slit 51. By setting the perpendicular crossing, feeding is coupled through this other coupling slit 51. Thus, the feeding microstrip 6 forms a T-shaped power divider. By setting the difference in the lengths of the projections of the first feeding branch 621 and the second feeding branch 622 located in the middle region part to be half of the dielectric wavelength, differential feeding of the two coupling slits 51 can be realized, ensuring the provision of excitations with equal amplitude and a phase difference of 90°, and ensuring that the antenna element realizes circular polarization radiation.

[0060] Specifically, the coupling slot 51 is divided into a first section 513 and a second section 514 along the length direction, and the demarcation line 515 between the first section 513 and the second section 514 is the projection of the center line of the first feeding stub 621 or the second feeding stub 622 on the first metal layer 5; wherein, the position of the demarcation line 515 is associated with the antenna reflection coefficient of the wideband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100.

[0061] Wherein, the first section 513 is the partial coupling slot 51 including the first arc slot 511, and the length of the first section 513 is L5; the second section 514 is the partial coupling slot 51 including the second arc slot 512, and the length of the second section 514 is L6.

[0062] In this embodiment, the coupling slot 51 is divided into two parts by the projection of the center line of the feeding stub of the feeding microstrip 6, and the relative position of the projection of the center line of the feeding stub of the feeding microstrip 6 and the coupling slot 51 is changed, so as to adjust the length L5 of the first section 513 and the length L6 of the second section 514, and the reflection coefficient of the antenna element can be adjusted.

[0063] Specifically, the length L5 of the first section 513 of the coupling slot 51 is approximately one-quarter of the dielectric wavelength, the length L6 of the second section 514 is approximately one-half of the dielectric wavelength, and the length difference between the first section 513 and the second section 514 is one-quarter of the dielectric wavelength.

[0064] Specifically, as Figure 1 shown, the middle section slot 516 may include a plurality of slot segments connected in turn by turning, so that the length of the middle section slot 516 can be increased in a limited space.

[0065] Specifically, as Figure 2 shown, both the first feeding stub 621 and the second feeding stub 622 include end stub portions 623 whose projections on the first metal layer 5 are located in the peripheral region. The lengths L7 of the two end stub portions 623 are equal, and the length L7 of the end stub portion 623 is associated with the antenna reflection system of the wideband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100.

[0066] In this embodiment, the feeding microstrip 6 has two end stub portions 623. By adjusting the length L7 of the end stub portion 623, the reflection coefficient of the antenna element can be adjusted.

[0067] Specifically, the dielectric constant of the second dielectric layer 2 is greater than the dielectric constants of the first dielectric layer 1 and the third dielectric layer 3.

[0068] In this embodiment, by setting the first dielectric layer 1 and the third dielectric layer 3 to have a lower dielectric constant and a harder material, they are suitable for multi-layer and multi-time lamination and are not easily deformed; by setting the second dielectric layer 2 to have a larger dielectric constant, the dielectric wavelength can be reduced, and then the length of the coupling slot 51 can be shortened, which is beneficial to reducing the volume of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100.

[0069] Specifically, the first dielectric layer 1, the second dielectric layer 2, and the third dielectric layer 3 are all millimeter-wave radio frequency plates.

[0070] In this embodiment, the antenna element is integrated on a multi-layer millimeter-wave radio frequency plate. For example, the millimeter-wave radio frequency plate can be a ceramic plate. Among them, the type number of the millimeter-wave radio frequency plate is selected and determined according to the antenna operating frequency band and the element spacing requirements to ensure that the antenna element has excellent radiation performance.

[0071] Specifically, a plurality of metal vias 8 are provided on both the second dielectric layer 2 and the third dielectric layer 3. The plurality of metal vias 8 are all connected to the first metal ground layer 5 and the second metal ground layer 7, and the plurality of metal vias 8 are arranged around the outer contours of the feeding microstrip 6 and the coupling slot 51 to enclose the feeding microstrip 6 and the coupling slot 51 within the range enclosed by the plurality of metal vias 8.

[0072] In this embodiment, by arranging a plurality of metal vias 8 to surround and enclose the feeding microstrip 6 and the coupling slot 51 to isolate the coupling slot 51 and the feeding microstrip 6, the radio frequency signals in the antenna element can be isolated, the isolation degree of the antenna element can be increased, and the influence of the electromagnetic radiation of the feeding circuit on the antenna pattern can be reduced.

[0073] Specifically, the plurality of metal vias 8 near the coaxial feeding point 71 are arranged around a part of the outer circumference of the coaxial feeding point 71.

[0074] In this embodiment, by arranging a plurality of metal vias 8 near the coaxial feeding point 71 around a part of the outer circumference of the coaxial feeding point 71 to semi-surround the coaxial feeding point 71, an outer metal layer similar to coaxial feeding is formed, leakage is reduced, and the isolation effect of the radio frequency signal is improved.

[0075] Specifically, the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100 further includes an adhesive layer 9. The adhesive layer 9 is sandwiched between the first dielectric layer 1 and the first metal ground layer 5, and between the second dielectric layer 2 and the third dielectric layer 3; the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100 is made by a multi-layer PCB co-pressing process.

[0076] In this embodiment, the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100 is realized by using a multi-layer PCB co-lamination process with three layers of dielectric. The adhesive layer 9 is used to bond and press the three layers of dielectric, the first metal ground layer 5, and the second metal ground layer 7 together, which is easy to process and implement, and reduces costs.

[0077] Specifically, the adhesive layer 9 is a prepreg, and the type number of the prepreg is determined according to the type number of the millimeter-wave RF board. For example, the adhesive layer 9 selects a prepreg with performance similar to that of the first dielectric layer 1.

[0078] In a specific embodiment, the millimeter-wave RF boards of the first dielectric layer 1 and the third dielectric layer 3 adopt Rogers4350B ceramic boards with a dielectric constant of 3.66. The dielectric constant is relatively low, the board is relatively hard, and it is not easy to deform during multi-layer and multi-time lamination. The millimeter-wave RF board of the second dielectric layer 2 adopts Rogers 6010 ceramic board with a dielectric constant of 10.2, and the coupling slot 51 will be shorter. The adhesive layer 9 between the ceramic boards is bonded with a prepreg of model FR28, with a dielectric constant of 2.8 and a thickness of 0.1 mm. The total thickness of the antenna element is 1.867 mm.

[0079] On the other hand, as Figure 3 shown, the embodiment of the present invention also provides a broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna array, including the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100 provided by any of the above embodiments.

[0080] By using the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100 of the above embodiment to form a phased array antenna array, the radiation pattern has good rotational symmetry, can effectively reduce the mutual coupling between array elements, and realize the broadband wide-angle scanning performance.

[0081] In a specific embodiment, as Figure 3 shown, in order to verify the symmetry characteristic of the radiation pattern of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100 of the present invention, a 4×4 array case is designed. The broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100 in the above specific embodiment is used as an array element to form a 4×4 array. The middle 2×2 array is the working array element, and the surrounding array elements are used as dummy elements. Based on this, it can be extended into an array of any scale, and the array parameters are the same as those of the middle 2×2 array.

[0082] As Figure 4As shown, it is the reflection coefficient curve graph of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element and the array element of the embodiment of the present invention. The figure shows the change curves of the reflection coefficient with frequency of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100 in the above specific embodiment and the middle element after arraying with this antenna element. In the figure, the horizontal axis represents frequency, with the unit (GHz); the vertical axis represents the value of the reflection coefficient, with the unit (dB).

[0083] As Figure 5 shown, it is the axial ratio curve graph of the maximum radiation direction of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element and the array element of the embodiment of the present invention. The figure shows the axial ratio of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100 in the above specific embodiment and the middle element after arraying with this antenna element. In the figure, the horizontal axis represents frequency, with the unit (GHz); the vertical axis represents the axial ratio value, with the unit (dB).

[0084] As Figure 6 shown, it is the radiation pattern of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element of the embodiment of the present invention. The figure shows the radiation pattern of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100 in the above specific embodiment. In the figure, the horizontal axis represents the angle, with the unit (°), and this angle is the included angle with the positive direction of the z-axis in the antenna coordinate system; the vertical axis represents the antenna gain amplitude value, with the unit (dB). The figure respectively shows the main polarization (LHCP) and cross polarization (RHCP) radiation patterns on the four planes of the phase angle 45°, 90°, and 135°.

[0085] As Figure 7 shown, it is the axial ratio pattern of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element of the embodiment of the present invention. The figure shows the axial ratio pattern of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100 in the above specific embodiment. In the figure, the horizontal axis represents the angle, with the unit (°), and this angle is the included angle with the positive direction of the z-axis in the antenna coordinate system; the vertical axis represents the antenna axial ratio value, with the unit (dB). The figure respectively shows the axial ratio patterns on the four planes of the phase angle 45°, 90°, and 135°.

[0086] As Figure 8 shown, it is the radiation pattern of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna array element of the embodiment of the present invention. The figure shows the radiation pattern of the middle element after arraying with the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100 in the above specific embodiment. In the figure, the horizontal axis represents the angle, with the unit (°), and this angle is the included angle with the positive direction of the z-axis in the antenna coordinate system; the vertical axis represents the antenna gain amplitude value, with the unit (dB). The figure respectively shows the phase angle The co-polarization (LHCP) and cross-polarization (RHCP) radiation patterns on the four surfaces of 45°, 90°, and 135°.

[0087] As Figure 9 shown, it is the axial ratio pattern of the array element of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna according to the embodiment of the present invention. The axial ratio pattern of the middle array element after the arraying of 100 groups of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna units in the above specific embodiment is given in the figure. In the figure, the horizontal coordinate axis represents the angle, with the unit (°), and this angle is the included angle with the positive direction of the z-axis in the antenna coordinate system; the vertical coordinate axis represents the antenna axial ratio value, with the unit (dB). The axial ratio patterns on the four surfaces of the phase angles 45°, 90°, and 135° are respectively given in the figure.

[0088] According to Figures 4 - 7 it can be seen that the technical indicators achieved by the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna unit 100 in the above specific embodiment are as follows:

[0089] According to Figure 4 it can be obtained that the bandwidth of the reflection coefficient (S11) of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna unit 100 below -10 dB: 24.8 GHz - 27.8 GHz, a total of 3 GHz, and the relative bandwidth reaches 11.5%.

[0090] According to Figure 5 it can be obtained that the bandwidth of the axial ratio below -3 dB in the maximum radiation direction of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna unit 100: 24.8 GHz - 27.4 GHz, a total of 2.6 GHz, and the relative bandwidth reaches 10%.

[0091] According to Figure 6 , the data of the co-polarization (LHCP) and cross-polarization (RHCP) radiation patterns on the four surfaces of 45°, 90°, and 135° of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna unit 100 are shown in the following table: The data of the co-polarization (LHCP) and cross-polarization (RHCP) radiation patterns on the four surfaces of 45°, 90°, and 135° of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna unit 100 are shown in the following table:

[0092]

[0093] It can be seen from the data in the above table that the 3 dB beam widths and on two surfaces, and on two surfaces are basically coincident, and the differences on the four surfaces are not significant, and the pattern has good rotational symmetry.

[0094] According to Figure 7 , the data of the 3 dB axial ratio beam range of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna unit 100 are shown in the following table:

[0095]

[0096] From the data in the above table, it can be obtained that the 3dB axial ratio beam of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100 is greater than 160°.

[0097] Through simulation optimization, the performance of the 4×4 array case composed of the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element 100 of the present invention has been verified, and the results are as follows:

[0098] According to Figure 4 it can be obtained that the bandwidth below -10dB of the reflection coefficient (S11) of the element antenna in the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna is: 25.1GHz - 27.6GHz, a total of 2.5GHz, and the relative bandwidth reaches 9.6%.

[0099] According to Figure 5 it can be obtained that the bandwidth below -3dB of the axial ratio in the maximum radiation direction of the element antenna in the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna is: 24.9GHz - 27.2GHz, a total of 2.3GHz, and the relative bandwidth reaches 8.8%.

[0100] According to Figure 8 , the data of the main polarization (LHCP) and cross polarization (RHCP) radiation patterns on the four planes of 45°, 90°, and 135° of the element in the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna are shown in the following table:

[0101]

[0102] It can be seen from the data in the above table that the 3dB beamwidth and on two planes, and on two planes are basically coincident, and the differences on the four planes are not significant, and the radiation pattern has good rotational symmetry. It is verified that the rotational symmetry of the antenna element plays a decisive role in array formation.

[0103] According to Figure 9 , the data of the 3dB axial ratio beam range of the element in the broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna are shown in the following table:

[0104]

[0105] It can be obtained from the data in the above table that the 3dB axial ratio beam range of the array antenna element (except for the 3dB axial ratio beam range of the plane reaches 225°) decreases, which is caused by the mutual coupling between adjacent elements after array formation; however, the minimum 3dB axial ratio beam range still reaches 118° It shows that the mutual coupling between array elements has been reduced.

[0106] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element, characterized in that include: A first dielectric layer, a second dielectric layer and a third dielectric layer are stacked in sequence; A radiation patch, arranged on a side of the first dielectric layer away from the second dielectric layer, the radiation patch being a circular microstrip patch; A first metal layer is sandwiched between the first dielectric layer and the second dielectric layer, two coupling slots and a plurality of isolation slots are provided on the first metal layer, the two coupling slots are arranged to be rotationally symmetrical about a rotation center, the rotation center coincides with the center of the radiation patch in the stacking direction, and one end of each coupling slot has a first arc slot bent toward one side, and the other end has a second arc slot bent toward the opposite other side, so as to excite two electromagnetic modes perpendicular to each other, and the plurality of isolation slots are arranged around the periphery of the two coupling slots; A feeding microstrip, sandwiched between the second dielectric layer and the third dielectric layer, the feeding microstrip comprising a connecting portion and a feeding portion, the feeding portion being arranged corresponding to the two coupling slots, and being used for coupling and feeding the radiation patch through the two coupling slots; The second metal layer is attached to a side of the third dielectric layer away from the second dielectric layer. The second metal layer is provided with a coaxial feeding point, and the coaxial feeding point is electrically connected to the connecting portion.

2. The broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element according to claim 1, wherein The length of the first arc gap is associated with the antenna reflection coefficient of the wide bandwidth angular scanning circularly polarized millimeter wave phased array antenna unit; the length of the second arc gap is associated with the position of the antenna axis ratio resonance point of the wide bandwidth angular scanning circularly polarized millimeter wave phased array antenna unit.

3. The broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element according to claim 1, wherein The coupling gap also has a middle gap, the first arc gap is connected to one end of the middle gap, and the second arc gap is connected to the other end of the middle gap; the two coupling gaps divide the first metal stratum into a middle area and a peripheral area, and the middle area is located between the two coupling gaps; The feeding part includes a first feeding branch and a second feeding branch, the first feeding branch and the second feeding branch are connected to opposite sides of one end of the connecting part; the projection of the connecting part on the first metal stratum is located between the two coupling slots, the projection of the first feeding branch on the first metal stratum is perpendicularly intersected with the middle slot of one coupling slot, and the projection of the second feeding branch on the first metal stratum is perpendicularly intersected with the middle slot of another coupling slot; and the difference between the length of the projection of the first feeding branch on the first metal stratum located in the middle area and the length of the projection of the second feeding branch on the first metal stratum located in the middle area is half a medium wavelength.

4. The broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element according to claim 3, characterized in that, The coupling slot is divided into a first section and a second section along the length direction, and the dividing line between the first section and the second section is the projection of the center line of the first feeding branch or the second feeding branch on the first metal stratum; the position of the dividing line is associated with the antenna reflection coefficient of the wide bandwidth angle scanning circularly polarized millimeter wave phased array antenna unit.

5. The broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element according to claim 3, wherein The first feeding stub and the second feeding stub both include end stub portions whose projections on the first metal ground plane are located in the peripheral region. The lengths of the two end stub portions are equal, and the length of the end stub portion is associated with the antenna reflection coefficient of the wideband wide-angle scanning circularly polarized millimeter-wave phased array antenna element.

6. The broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element according to any one of claims 1 to 5, characterized in that The dielectric constant of the second dielectric layer is greater than the dielectric constants of the first dielectric layer and the third dielectric layer.

7. The broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element according to any one of claims 1 to 5, characterized in that, The first dielectric layer, the second dielectric layer, and the third dielectric layer are all millimeter-wave RF laminates.

8. The broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element according to any one of claims 1 to 5, characterized in that A plurality of metal vias are provided on both the second dielectric layer and the third dielectric layer. The plurality of metal vias are all connected to the first metal ground plane and the second metal ground plane, and the plurality of metal vias are arranged around the outer contours of the feeding microstrip and the coupling slot to enclose the feeding microstrip and the coupling slot within the range enclosed by the plurality of metal vias.

9. The broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element according to claim 8, wherein The plurality of metal vias near the coaxial feeding point are arranged around a part of the outer periphery of the coaxial feeding point.

10. The broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna element according to claim 8, characterized in that, The wideband wide-angle scanning circularly polarized millimeter-wave phased array antenna element further includes an adhesive layer, which is sandwiched between the first dielectric layer and the first metal ground plane, and between the second dielectric layer and the third dielectric layer; the wideband wide-angle scanning circularly polarized millimeter-wave phased array antenna element is made by a multi-layer PCB co-pressing process.

11. A broadband wide-angle scanning circularly polarized millimeter-wave phased array antenna array, characterized in that It includes the wideband wide-angle scanning circularly polarized millimeter-wave phased array antenna element according to any one of claims 1 to 10.

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