A Ka-band circularly polarized antenna unit, antenna array and phased array on satellite

Abstract

The application provides a Ka-band circularly polarized antenna unit, an antenna array and a phased array on a satellite, and belongs to the technical field of antennas.The application aims to solve the connection problem between the phased array and a T / R component and the wideband wide-angle radiation problem.The phased array comprises a radiation structure in an upper layer, a parasitic structure in an intermediate layer and a feeding structure in a lower layer.The radiation structure is composed of upper metal patches and can realize circularly polarized antenna beam radiation.The feeding is realized by coupling transmission from the lowermost metal probe to the upper metal to realize radiation.A metal via hole is added around the radiation antenna to reduce the coupling effect between the antennas.The rotation angle of each antenna unit and the phase of the corresponding phase shifter are the same and are n times of 90 DEG, wherein n is 0, 1, 2 or 3;the rotation angle difference of any two adjacent antenna units and the phase difference of the phase shifter are both 90 DEG, so as to be matched with the bottom T / R component feeding hole.The application can be used for millimeter wave antenna communication and high-resolution radar imaging.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology and relates to a phased array antenna, particularly to a spaceborne Ka-band circularly polarized antenna element, antenna array and phased array, which can be used for millimeter-wave antenna communication and high-resolution radar imaging. Background Technology

[0002] Millimeter waves refer to electromagnetic waves with frequencies ranging from 30 GHz to 300 GHz, corresponding to wavelengths of 1 mm to 10 mm. Millimeter wave antennas offer advantages such as wide bandwidth, large communication capacity, and high target recognition resolution. Within the millimeter wave band, the Ka-band has a frequency range of 26.5–40 GHz, offering a wide bandwidth and large transmission capacity, making it particularly suitable for satellite communication. A phased array antenna is an array antenna that controls the radiation direction by adjusting the radiation phase of each antenna element. Compared to mechanically scanned antennas that add a mechanical scanning structure to the array antenna, phased array antennas offer more stable scanning speed and direction, and their beam scanning array has significantly stronger anti-interference capabilities than ordinary arrays.

[0003] The phased array T / R (Transmitter and Receiver) module, also known as the phased array transceiver module, is vertically integrated and mounted below the phased array. It has regularly arranged channel output ports that connect to the phased array feed ports, providing power excitation to the phased array antennas. The size of the T / R module determines the minimum array size of the phased array, and the number of channels in the T / R module determines the maximum number of radiating elements in the phased array.

[0004] All radiating elements, their T / R components, and other components can be combined to form an active microstrip phased array antenna. Currently, phased array antennas have been applied to aircraft, which has played a very important practical role in improving the stealth and maneuverability of aircraft. In particular, broadband scanning circularly polarized phased arrays have great application and engineering value in various communication systems such as radar, satellite communication, and missile guidance.

[0005] Circularly polarized phased array antennas are finding increasingly widespread applications. Compared to linearly polarized antennas, circularly polarized antennas can eliminate polarization distortion losses caused by the ionospheric Faraday rotation effect, and can adapt to signal reception on carriers that are violently swinging or rolling. Microstrip antennas are widely used due to their advantages such as low profile, easy conformal integration with the carrier, and ease of circular polarization. However, microstrip antennas are high-Q resonant antennas, and their narrow operating bandwidth limits further applications. Wireless communication systems are also placing increasingly higher demands on circularly polarized phased array antennas, especially wideband and wide-angle scanning. Therefore, how to improve the bandwidth and wide-angle scanning capability of circularly polarized patch antennas has become one of the urgent problems to be solved in circularly polarized phased array antenna technology.

[0006] To address the impedance bandwidth and axial ratio bandwidth characteristics of circularly polarized phased array antenna elements, most researchers both domestically and internationally have focused on modifying the antenna's structural form. For example, L.-K. Zhang and Y.-X. Wang et al. published a paper titled "Cavity-Backed Circularly Polarized Cross-Dipole Phased Arrays" in IEEE Antennas and Wireless Propagation Letters, Issue 9, in 2021, proposing a 16×16 element Ku-band circularly polarized phased array. The antenna elements include a cross dipole, a metallic cavity, and a threaded SMP connector. The metallic cavity increases the antenna gain and reduces the mutual coupling between array elements, thus ensuring good impedance matching and axial ratio during two-dimensional beam scanning. The proposed phased array achieves an impedance bandwidth of 10.1% and an element axial ratio bandwidth of 8.1%. It achieves a main lobe axial ratio of less than 2dB within the ±40° scanning range and a gain fluctuation of less than 3dB during scanning.

[0007] Patent CN114865328A (A Low-Profile Circularly Polarized Stealth Phased Array Antenna) discloses a double-layer metal patch antenna with surrounding metallized vias. This antenna achieves radiation through double-layer excitation of the bottom patch and parasitic stimulation of the top patch, ultimately achieving an impedance bandwidth of 10% and an axial ratio bandwidth of 5.6%, but does not achieve broadband characteristics. Summary of the Invention

[0008] In order to overcome the shortcomings of the prior art, the present invention aims to provide a spaceborne Ka-band circularly polarized antenna element, antenna array and phased array to solve the technical problems of narrow circular polarization axial ratio bandwidth, narrow impedance bandwidth and narrow scanning angle of the existing circularly polarized phased array antenna element, the connection problem between the antenna array and the T / R component and the wide bandwidth angle radiation problem, and reduce the complexity of the connection structure.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A spaceborne Ka-band circularly polarized antenna unit includes a first dielectric substrate, a first prepreg layer, a second dielectric substrate, a second prepreg layer, and a third dielectric substrate arranged sequentially from bottom to top.

[0011] A first upper metal ring and a first upper metal patch are printed on the upper surface of the first dielectric substrate; a metallized blind via is provided in the first dielectric substrate; the first upper metal patch is located inside the first upper metal ring and is isolated from each other;

[0012] The second dielectric substrate has a cavity structure with a hollowed-out center to provide a dielectric cavity;

[0013] The upper surface of the third dielectric substrate is printed with a second upper metal ring and a second upper metal patch, and the lower surface is printed with a lower metal patch. The second upper metal patch is located inside the second upper metal ring and is isolated from each other. Metallized vias are provided through the first dielectric substrate, the first prepreg layer, the second dielectric substrate, the second prepreg layer and the third dielectric substrate.

[0014] The first upper metal ring and the second upper metal ring are connected through the metallized vias, and the first upper metal patch is connected to the output port of the T / R assembly through the metallized blind vias for power supply.

[0015] The second upper metal patch, the lower metal patch, and the first upper metal patch are coupled and fed to radiate.

[0016] In one embodiment, the horizontal cross-sections of the first dielectric substrate, the first prepreg layer, the second dielectric substrate, the second prepreg layer, and the third dielectric substrate are regular quadrilaterals with equal areas; the first upper metal ring and the second upper metal ring are both closed frames of regular quadrilaterals, and there are multiple metallized vias that are evenly distributed along the closed frames.

[0017] In one embodiment, the first upper metal patch is composed of a first part, a second part, and a third part. The first part and the second part are both arrow-shaped, with the arrow pointing away from the center of the first dielectric substrate. They are symmetrically arranged and connected at the tail. The width of the connection part is less than the width of the widest part of the arrow. The third part is composed of a rectangle and a semicircular ring. One side of the rectangle is connected to the arrow side of the second part, and the semicircular ring is connected to the opposite side of one side of the rectangle.

[0018] The second upper metal patch consists of four small units. The four small units are arranged in a centrally symmetrical manner, and two adjacent small units are arranged symmetrically about the diagonal of a regular quadrilateral. Any two small units at the diagonal are regular quadrilaterals with a missing corner, and the missing corner is located away from the center. The other two small units are regular quadrilaterals with side lengths equal to the side lengths of the square with the missing corner.

[0019] The lower metal patch consists of four small units, each of which is a regular quadrilateral arranged symmetrically at the center. Furthermore, adjacent small units are symmetrical about the line connecting the centers of opposite sides of the regular quadrilateral.

[0020] In one embodiment, the spaceborne Ka-band circularly polarized antenna unit further includes a third prepreg layer and a fourth dielectric substrate located sequentially above the third dielectric substrate; the fourth dielectric substrate is a metal-free dielectric substrate used to broaden the antenna beam.

[0021] The present invention also provides a spaceborne Ka-band circularly polarized antenna array, which is composed of N×N antenna subarrays distributed in a rectangular array. Each antenna subarray is composed of four spaceborne Ka-band circularly polarized antenna elements distributed in a rectangular array, where N is an even integer greater than or equal to 2.

[0022] The present invention also provides a phased array, comprising N feeding transmission structures, N T / R components, and the aforementioned spaceborne Ka-band circularly polarized antenna array;

[0023] Each of the aforementioned feed transmission structures is disposed below one of the spaceborne Ka-band circularly polarized antenna elements, and the feed transmission structure is a metal layer with several T / R component output ports arranged thereon.

[0024] Each of the T / R components is disposed below one of the power transmission structures, and the output terminal of the T / R component is connected to the first upper metal patch for power supply through the T / R component output port, the metallized blind via, and the first upper metal patch.

[0025] Each of the T / R components includes four phase shifters. In the same antenna subarray, each of the phase shifters is connected to one of the spaceborne Ka-band circularly polarized antenna elements. The rotation angle of each of the spaceborne Ka-band circularly polarized antenna elements is the same as the phase of the phase shifter connected to it and is n times 90°, where n is 0, 1, 2 or 3.

[0026] In the same antenna subarray, the rotation angle difference between any two adjacent spaceborne Ka-band circularly polarized antenna elements is 90°, and / or the phase difference between any two adjacent phase shifters is 90°.

[0027] In one embodiment, the power supply transmission structure is a metal layer printed on the lower surface of a dielectric substrate.

[0028] In one embodiment, N is set to 4, forming a 64-element Ka-band circularly polarized phased array. The beamwidth of the azimuth and elevation planes of the spaceborne Ka-band circularly polarized antenna element is 113°, the axial ratio within the beamwidth range is less than 3dB, and the horizontal beamwidth is 18° when scanning ±55°. The array gain of the 64-element Ka-band circularly polarized phased array is 23.12dB, the horizontal beamwidth is 12°, and the sidelobe level is 13.2dB when in phase and at equal amplitude.

[0029] Compared with existing technologies, the spaceborne Ka-band circularly polarized antenna unit of the present invention can not only achieve circular polarization operation and a wide beam pattern, and can achieve large-angle scanning after arraying, but also has the characteristics of simple and compact structure, low profile, low cost, high reliability, and stable performance. Attached Figure Description

[0030] Figure 1 This is a structural diagram of the spaceborne Ka-band circularly polarized antenna unit of the present invention.

[0031] Figure 2 This is a vertical structure diagram of the spaceborne Ka-band circularly polarized antenna unit of the present invention.

[0032] Figure 3 This is a schematic diagram of the horizontal surface of the upper surface of the first dielectric substrate.

[0033] Figure 4 This is a schematic diagram of the upper surface of the second dielectric substrate.

[0034] Figure 5 This is a schematic diagram of the horizontal surface of the upper surface of the third dielectric substrate.

[0035] Figure 6 This is a schematic diagram of the horizontal lower surface of the third dielectric substrate.

[0036] Figure 7 This is a schematic diagram of the overall structure of the antenna subarray of the present invention.

[0037] Figure 8 This is a schematic diagram of the overall structure of the phased array of the present invention.

[0038] Figure 9 This is a schematic diagram of the BGA structure at the output terminal of the T / R component.

[0039] Figure 10 This is a VSWR diagram for the antenna element.

[0040] Figure 11 This is a diagram showing the axial ratio of the antenna elements.

[0041] Figure 12 The radiation pattern of the antenna element is shown at 29.5 GHz.

[0042] Figure 13 This is the radiation pattern of the antenna array at 0° for 29.5 GHz.

[0043] Figure 14 This is a plot of the axial ratio of the antenna array at 0°.

[0044] Figure 15 The radiation pattern of the antenna array at 29.5 GHz scanning 55°.

[0045] Figure 16 The aspect ratio diagram is shown when the antenna array is scanned at 55°. Detailed Implementation

[0046] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings and examples.

[0047] like Figure 1 and Figure 2As shown, the first objective of this invention is to provide a spaceborne Ka-band circularly polarized antenna unit, which mainly includes a first dielectric substrate 8, a first prepreg layer 9, a second dielectric substrate 10, a second prepreg layer 11 and a third dielectric substrate 12 arranged sequentially from bottom to top.

[0048] refer to Figure 1 , Figure 2 and Figure 3 A first upper metal ring 811 and a first upper metal patch 812 are printed on the upper surface of the first dielectric substrate 8. Metallized blind vias 5 are provided in the first dielectric substrate 8. The first upper metal patch 812 is located within the first upper metal ring 811 and is isolated from it. The primary function of the first dielectric substrate 8 and its pattern is to provide power.

[0049] refer to Figure 1 , Figure 2 and Figure 4 The first semi-cured layer 9 is mainly used to connect the first dielectric substrate 8 and the second dielectric substrate 10. The second dielectric substrate 10 adopts a cavity structure with a hollow center to provide a dielectric cavity, and a metal ring can also be provided on its edge.

[0050] The second semi-cured layer 11 is mainly used to connect the second dielectric substrate 10 and the third dielectric substrate 12. (Reference) Figure 1 , Figure 2 , Figure 5 and Figure 6 The upper surface of the third dielectric substrate 12 is printed with a second upper metal ring 1201 and a second upper metal patch 1202, and the lower surface is printed with a lower metal patch 1203. The second upper metal patch 1202 is located within the second upper metal ring 1201 and is isolated from each other. A metallized via 4 is provided through the first dielectric substrate 8, the first prepreg layer 9, the second dielectric substrate 10, the second prepreg layer 11 and the third dielectric substrate 12. The main function of the third dielectric substrate 12 and its pattern is to couple and feed power and then radiate.

[0051] The first upper metal ring 811 and the second upper metal ring 1201 are connected by metallized vias 4, and there can be multiple metallized vias 4, which are arranged at equal intervals. The first upper metal patch 812 is connected to the output port 201 of the T / R module through a metallized blind via 5 for power supply.

[0052] The second upper metal patch 1202 and the lower metal patch 1203 are coupled to the first upper metal patch 812 for radiation.

[0053] Ka-band is a commonly used millimeter-wave frequency band for satellite communication. Satellite communication requires circularly polarized beams because electromagnetic waves undergo an irreversible Faraday rotation effect when passing through the atmosphere. However, circularly polarized beams do not significantly affect the Faraday effect. The electrical size of the antenna needs to be less than half a wavelength to effectively suppress grating lobes during beam scanning. Therefore, antennas meeting these requirements can be used as spaceborne Ka-band circularly polarized antennas.

[0054] The spaceborne Ka-band circularly polarized antenna element of this invention primarily serves as a radiating mechanism. Its second upper metal patch 1202 enables circularly polarized antenna beam radiation. Power is supplied by a metallized blind aperture 5 and transmitted via coupling to the second upper metal patch 1202 and the lower metal patch 1203 for radiation. The surrounding metallized vias 4 reduce coupling between antennas.

[0055] In one embodiment of the present invention, the horizontal cross-sections of the first dielectric substrate 8, the first semi-cured layer 9, the second dielectric substrate 10, the second semi-cured layer 11, and the third dielectric substrate 12 are regular quadrilaterals with equal areas; the first upper metal ring 811 and the second upper metal ring 1201 are both closed frames of regular quadrilaterals, and there are multiple metallized vias 4, which are distributed at equal intervals along the closed frames.

[0056] In this embodiment, the shape ensures the generation of a broadband circularly polarized beam, by Figure 11 The effect can be seen. Both the first upper metal ring 811 and the second upper metal ring 1201 are closed frames of regular quadrilaterals. There are multiple metallized vias 4, which are evenly distributed along the closed frames, which can reduce the coupling between antennas.

[0057] In one embodiment of the present invention, in order to achieve impedance matching and circularly polarized beams, the specific structures of each metal patch are provided as follows:

[0058] The first upper metal patch 812 consists of a first part 8121, a second part 8122, and a third part 8123. The first part 8121 and the second part 8122 are both arrow-shaped, with the arrow pointing away from the center of the first dielectric substrate 8. They are symmetrically arranged and connected at the tail. The width of the connecting portion 8124 is smaller than the width of the widest part of the arrow, thus forming two symmetrical recesses 8125 at the connection point. The third part 8123 consists of a rectangle 81231 and a semicircular ring 81232. One side of the rectangle 81231 is connected to the arrow side of the second part 8122, and the semicircular ring 81232 is connected to the opposite side of the rectangle 81231. The metallized blind via 5 is projected onto the center of the semicircular ring 81232. (Reference) Figure 3 In this embodiment, feasible parameters are also provided. Specifically, the length of the arrow side of the first part 8121 and the second part 8122 is l. 10 =l 11=1.45mm, the length of the recess 8125 is l 12 =0.25mm, width l9=0.4mm, rectangle 81231 is used as the feeder cable, its length is l 13 =0.8mm, width is l 14 =1mm, the semi-circular ring 81232 is the power supply port, with inner and outer radii of r2 = 0.1mm and r3 = 0.45mm respectively. Meanwhile, refer to... Figure 4 This embodiment provides a feasible dimension for the second dielectric substrate 10, wherein the width of the central cavity is l8 = 3.75 mm; the cavity is achieved by chamfering, and the chamfer radius is r1 = 0.25 mm.

[0059] The second upper metal patch 1202 consists of four small units 12021, 12022, 12023, and 12024, each small unit being a parasitic patch. The four small units 12021, 12022, 12023, and 12024 are centrally symmetrically arranged, and adjacent small units are symmetrically arranged about the diagonal of a regular quadrilateral. Any two small units at opposite corners form a regular quadrilateral with a missing corner, the missing corner being located away from the center. The other two small units are regular quadrilaterals with side lengths equal to the side length of the square with the missing corner. In this embodiment, the first small unit 12021 and the third small unit 12023 are diagonally opposite and are both regular quadrilaterals; the second small unit 12022 and the fourth small unit 12024 are diagonally opposite and are both regular quadrilaterals with missing corners. The side lengths of the regular quadrilaterals in all four small units are equal. Figure 5 The document also provides feasible parameters, specifically the diameter r of the metallized via 4. 0＝ 0.2mm, the spacing between adjacent metallized vias 4 l4 = 0.5mm, the antenna element size (i.e. the side length of the regular quadrilateral dielectric substrate) l0 = 5mm, in the second upper metal patch 1202, the side length of the four small elements l1 = 0.9mm, the spacing between adjacent small elements l2 = 0.4mm, the length of the notched corner of the second small element 12022 and the fourth small element 12024, i.e. the patch chamfer, l5 = 0.73mm, and the width of the second upper metal ring 1201 l3 = 0.5mm.

[0060] The lower metal patch 1203 is also composed of four small units 12031, 12032, 12033, and 12034. These four small units 12031, 12032, 12033, and 12034 are all regular quadrilaterals, arranged symmetrically at the center, and adjacent small units are symmetrically arranged about the center line connecting opposite sides of the quadrilateral. Figure 6The document also provides feasible parameters. Specifically, the fifth unit 12031, the sixth unit 12032, the seventh unit 12033, and the eighth unit 12034 are distributed clockwise. The fifth unit 12031 and the sixth unit 12032, as well as the seventh unit 12033 and the eighth unit 12034, are symmetrical about one center line of the dielectric substrate, while the fifth unit 12031 and the eighth unit 12034, as well as the seventh unit 12033 and the sixth unit 12032, are symmetrical about another center line of the dielectric substrate. Here, the four units 12031, 12032, 12033, and 12034 are equal in length, with a side length of l6 = 0.6 mm and a patch spacing of l7 = 1 mm.

[0061] In this embodiment, the above structure excites two equally orthogonal electric field components, thereby achieving a circularly polarized beam. Impedance matching can be achieved by adjusting the antenna's size parameters.

[0062] In one embodiment of the present invention, the spaceborne Ka-band circularly polarized antenna unit further includes a third semi-cured layer 13 and a fourth dielectric substrate 14 located sequentially above the third dielectric substrate 12. The fourth dielectric substrate 14 is a non-metallized dielectric substrate used to broaden the antenna beam.

[0063] At the same time, such as Figure 2 As shown, this embodiment also provides some feasible parameters. The height of the first dielectric substrate 8 is h1 = 0.508 mm; the height of the first semi-cured layer 9 is h2 = 0.2 mm; the height of the second dielectric substrate 10 is also h1 = 0.508 mm; the height of the second semi-cured layer 11 is h3 = 0.1 mm; the height of the third dielectric substrate 12 is h4 = 0.254 mm; the height of the third semi-cured layer 13 is also h3 = 0.1 mm; the height of the fourth dielectric substrate 14 is h5 = 0.127 mm; the height of the dielectric cavity (i.e., the height of the first semi-cured layer 9 and the second dielectric substrate 10) is h6 = h1 + h2 = 0.708 mm.

[0064] In the above embodiments, each dielectric substrate uses a Rogers 4350 microwave dielectric board, and its surface is treated with immersion nickel-gold. The metal layers such as metal patches and metal rings are made of copper, and their surfaces are also treated with immersion nickel-gold. The power supply probe, i.e., the metallized blind via 5, is made of copper.

[0065] refer to Figure 7 The second objective of this invention is to provide a spaceborne Ka-band circularly polarized antenna array, which consists of N×N antenna subarrays arranged in a rectangular array. Each antenna subarray is composed of four spaceborne Ka-band circularly polarized antenna elements arranged in a central rotationally symmetrical manner. In this invention, they are specifically arranged in a rectangular array, where N is an even integer greater than or equal to 2.

[0066] refer to Figure 7 and Figure 8 A third objective of this invention is to provide a phased array comprising N feed transmission structures 2, N T / R components 3, and the aforementioned spaceborne Ka-band circularly polarized antenna array.

[0067] The spaceborne Ka-band circularly polarized antenna array serves as the radiating structure, and the feeding transmission structure 2 is located below the spaceborne Ka-band circularly polarized antenna element. The feeding transmission structure 2 can be a metal layer with several T / R component output ports 201 arranged on it.

[0068] Each T / R component 3 is disposed below a power supply transmission structure 2. The output terminal of the T / R component 3 is connected to the first upper metal patch 812 for power supply through the T / R component output port 201 and the metallized blind via 5. Specifically, the power supply connection can be achieved by soldering BGA and T / R component 3, and can be sintered to the bottom of the power supply transmission structure 2.

[0069] Each of the T / R components 3 includes four phase shifters. In the same antenna subarray, each phase shifter is connected to one of the spaceborne Ka-band circularly polarized antenna elements. The rotation angle of each spaceborne Ka-band circularly polarized antenna element is the same as the phase of the phase shifter connected to it and is n times 90°. In order to achieve consistency between the antenna rotation phase and the phase shifter phase, n is 0, 1, 2 or 3.

[0070] In the same antenna subarray, the rotation angle difference between any two adjacent spaceborne Ka-band circularly polarized antenna elements is 90°, and / or the phase difference between any two adjacent phase shifters is 90°, achieving power matching with the T / R assembly 3. This invention can be used for millimeter-wave antenna communication and high-resolution radar imaging.

[0071] In one embodiment of the present invention, the power supply transmission structure 2 is a metal layer printed on the lower surface of the dielectric substrate 8. (See reference...) Figure 9 It is a regular quadrilateral with several holes distributed thereon, serving as the output port 201 of the T / R component.

[0072] In this invention, one T / R component 3 corresponds to four ports and adopts a central rotational symmetry structure. The dimensions of the T / R component 3 are consistent with the length and width of the antenna to facilitate BGA soldering. In this embodiment, the length and width dimensions are designed to be 10×10mm, and the antenna profile height (i.e., the height from the first dielectric substrate 8 to the fourth dielectric substrate 14) is 1.77mm. Figure 7The diagram shows an antenna subarray comprising four antenna elements 11a, 12a, 13a, and 14a, and four phase shifters 31a, 32a, 33a, and 34a connected to each antenna element. For example, the rotation angle of antenna element 11a is the same as the phase of its connected phase shifter 31a and is 0 times 90° (0). The rotation angle of antenna element 12a is the same as the phase of its connected phase shifter 32a and is 1 times 90° (90°). The rotation angle of antenna element 13a is the same as the phase of its connected phase shifter 33a and is 2 times 90° (180°). The rotation angle of antenna element 14a is the same as the phase of its connected phase shifter 34a and is 3 times 90° (270°). Therefore, the difference in rotation angle between any two adjacent antenna elements, and the difference in phase between any two adjacent phase shifters, is 90°.

[0073] Therefore, the cross-polarization component generated by antenna element 11a cancels out the cross-polarization components coupled to antenna elements 12a and 14a. Furthermore, the cross-polarization component generated by antenna element 12a cancels out the cross-polarization component coupled to antenna element 13a, and the cross-polarization component generated by antenna element 13a cancels out the cross-polarization component coupled to antenna element 14a, thus achieving a better dominant polarization component. When this antenna element array is used for beam scanning, a wider scanning angle can be obtained, thereby improving the scanning angle of the circularly polarized phased array antenna. The scanning angle can reach 60° with an axial ratio of less than 3dB. Moreover, the Ka-band circularly polarized antenna element has the advantages of small size, light weight, and low profile.

[0074] This embodiment uses Figure 7 Taking the example shown, antenna element 11a is the reference point, and the phase shifter 31a connected to antenna element 11a has a phase of 0°; antenna element 12a is rotated 90° relative to antenna element 11a, and the phase shifter 32a connected to antenna element 12a has a phase of 90°; antenna element 13a is rotated 180° clockwise relative to antenna element 11a, and the phase shifter 33a connected to antenna element 13a has a phase of 180°; antenna element 14a is rotated 270° clockwise relative to antenna element 11a, and the phase shifter 34a connected to antenna element 14a has a phase of 270°. The spacing between antenna element 11a and antenna elements 12a and 14a is 5.15mm; the spacing between antenna element 12a and antenna element 13a is 5.15mm; and the spacing between antenna element 13a and antenna element 14a is 5.15mm.

[0075] In one embodiment of the present invention, N is set to 4, and a 64-element Ka-band circularly polarized phased array is constructed using 4×4 antenna subarrays. However, those skilled in the art should understand that the Ka-band circularly polarized phased array antenna can also have other combinations and quantities, such as 2×2, 4×4, 6×6, 8×8, etc. This embodiment does not limit this. When using this Ka-band circularly polarized phased array antenna for beam scanning, a wider scanning angle can be obtained, thereby improving the scanning angle of the circularly polarized phased array antenna, which can reach 55°. Moreover, the Ka-band circularly polarized antenna element has the advantages of small size, light weight, and low profile.

[0076] Figure 10 The VSWR of the active phased array antenna elements shows that the impedance bandwidth of the active phased array antenna elements with a VSWR of less than 1.8 is 24.76–34.8 GHz.

[0077] Figure 11 The diagram shows the axial ratio bandwidth of the active phased array antenna elements. It can be seen that the axial ratio bandwidth of the antenna elements with an axial ratio of less than 3dB is 26.89–32.91 GHz.

[0078] like Figure 12 As shown in the antenna pattern at 29.5 GHz, it can be seen that the 3dB beamwidth of both the E-plane and H-plane is 113°.

[0079] like Figure 13 As shown, the antenna array radiation pattern when not scanning at 29.5 GHz shows that the Ka-band circularly polarized phased array antenna has a beamwidth of 12° and a sidelobe level of 13.2 dB.

[0080] like Figure 14 As shown in the diagram, the axial ratio of the linear array when it is not scanned at 29.5 GHz shows that the axial ratio of the Ka-band circularly polarized phased array antenna is less than 3 dB.

[0081] like Figure 15 As shown, the radiation pattern of the antenna array when scanning 55° at 29.5GHz shows that the beamwidth of the Ka-band circularly polarized phased array antenna when scanning 55° is 18°.

[0082] like Figure 16 As shown in the diagram, the axial ratio of the linear array when scanning 55° at 29.5 GHz shows that the axial ratio of the Ka-band circularly polarized phased array antenna is less than 3 dB.

[0083] It should be noted that the above description is merely an embodiment of the present invention and is not limited to the embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and basic principles of the present invention should be considered equivalent substitutions. The scope of the invention is defined by the appended claims rather than the foregoing description; therefore, all variations falling within the meaning and scope of the equivalent elements of the claims are intended to be included within the present invention.

[0084] In summary, the antenna unit of the present invention is connected to the T / R component output port 201 via a metallized blind via 5 using a first upper metal patch 812. This connection drives the second upper metal patch 1202 and the lower metal patch 1203 to achieve radiation. By loading the second upper metal patch 1202 and the lower metal patch 1203 with different structures, as well as loading a dielectric cavity, the electric field distribution of the antenna can be changed, thereby broadening the antenna bandwidth and axial ratio bandwidth. In the embodiment provided by the present invention, the antenna unit can achieve an impedance bandwidth of 33.3% and an axial ratio bandwidth of 16.6%. Simultaneously, loading the surrounding metallized vias 4 reduces the influence of higher-order modes, thereby reducing the coupling between antenna units. The fourth dielectric substrate 14 covering the top layer can broaden the antenna beamwidth, thereby achieving large-angle scanning.

[0085] Furthermore, this invention uses a rectangular array to form an antenna subarray consisting of four groups of antenna elements rotated sequentially by 90°. The rotation angle of each antenna element is set to be the same as the phase of the T / R component and is an integer multiple of 90°. Additionally, the rotation angle difference between any two adjacent antenna elements and / or the phase difference of their corresponding phase shifters is set to 90°. Therefore, the cross-polarization components generated by each antenna element can cancel each other out with the cross-polarization components coupled to adjacent antenna elements, resulting in better main polarization. When using the array formed by the antenna subarray of this invention for beam scanning, a wider scanning angle can be obtained, thereby improving the scanning angle of the circularly polarized phased array antenna. A scanning angle of 55° can be achieved with an axial ratio of less than 3dB. Moreover, the Ka-band circularly polarized antenna element has the advantages of small size, light weight, and low profile. The antenna uses BGA and T / R components welded together and sintered at the bottom of the reflector plate, resulting in a small array aperture and higher integration.

Claims

1. A spaceborne Ka-band circularly polarized antenna element, characterized in that, It includes a first dielectric substrate (8), a first semi-cured layer (9), a second dielectric substrate (10), a second semi-cured layer (11), and a third dielectric substrate (12) arranged sequentially from bottom to top. A first upper metal ring (811) and a first upper metal patch (812) are printed on the upper surface of the first dielectric substrate (8); a metallized blind via (5) is provided in the first dielectric substrate (8); the first upper metal patch (812) is located inside the first upper metal ring (811) and is isolated from each other; The second dielectric substrate (10) has a cavity structure with a hollow center to provide a dielectric cavity; The upper surface of the third dielectric substrate (12) is printed with a second upper metal ring (1201) and a second upper metal patch (1202), and the lower surface is printed with a lower metal patch (1203). The second upper metal patch (1202) is located inside the second upper metal ring (1201) and is isolated from each other. Metallized vias (4) are provided through the first dielectric substrate (8), the first semi-cured layer (9), the second dielectric substrate (10), the second semi-cured layer (11) and the third dielectric substrate (12). The first upper metal ring (811) and the second upper metal ring (1201) are connected through the metallized via (4), and the first upper metal patch (812) is connected to the T / R assembly output port (201) through the metallized blind via (5) for power supply. The second upper metal patch (1202) and the lower metal patch (1203) are coupled and fed to the first upper metal patch (812) for radiation. The first upper metal patch (812) is composed of a first part, a second part and a third part. The first part and the second part are both arrow-shaped, with the arrow pointing away from the center of the first dielectric substrate (8). They are symmetrically arranged and connected at the tail. The width of the connection part is less than the width of the widest part of the arrow. The third part is composed of a rectangle and a semi-circular ring. One side of the rectangle is connected to the arrow side of the second part, and the semi-circular ring is connected to the opposite side of one side of the rectangle. The second upper metal patch (1202) consists of four small units. The four small units are arranged in a centrally symmetrical manner, and two adjacent small units are arranged symmetrically about the diagonal of a regular quadrilateral. Any two small units at the diagonal are regular quadrilaterals with a missing corner, and the missing corner is located away from the center. The other two small units are regular quadrilaterals with side lengths equal to the side lengths of the square with the missing corner. The lower metal patch (1203) consists of four small units, all of which are regular quadrilaterals arranged in a centrally symmetrical manner, and adjacent small units are symmetrical about the center line connecting the opposite sides of the regular quadrilateral.

2. The spaceborne Ka-band circularly polarized antenna element according to claim 1, characterized in that, The horizontal cross-sections of the first dielectric substrate (8), the first semi-cured layer (9), the second dielectric substrate (10), the second semi-cured layer (11), and the third dielectric substrate (12) are regular quadrilaterals and have equal areas; the first upper metal ring (811) and the second upper metal ring (1201) are both closed frames of regular quadrilaterals, and there are multiple metallized vias (4) that are evenly distributed along the closed frames.

3. The spaceborne Ka-band circularly polarized antenna element according to claim 1, characterized in that, The spaceborne Ka-band circularly polarized antenna unit also includes a third semi-cured layer (13) and a fourth dielectric substrate (14) located sequentially above the third dielectric substrate (12); the fourth dielectric substrate (14) is a non-metallized dielectric substrate used to broaden the antenna beam.

4. A spaceborne Ka-band circularly polarized antenna array, characterized in that, It consists of N×N antenna subarrays arranged in a rectangular array, wherein each antenna subarray is composed of four spaceborne Ka-band circularly polarized antenna elements as described in claim 1, 2, or 3 arranged in a rectangular array, where N is an even integer greater than or equal to 2.

5. A phased array, characterized in that, It includes N feeding transmission structures (2), N T / R components (3), and the spaceborne Ka-band circularly polarized antenna array as described in claim 4; Each of the aforementioned feed transmission structures (2) is disposed below a satellite-borne Ka-band circularly polarized antenna unit, and the feed transmission structure (2) is a metal layer with several T / R component output ports (201) arranged thereon; Each of the T / R components (3) is disposed below a power transmission structure (2), and the output end of the T / R component (3) is connected to the first upper metal patch (812) through the T / R component output port (201) and the metallized blind hole (5) for power supply; Each of the T / R components (3) includes four phase shifters in the same antenna subarray. Each of the phase shifters is connected to one of the spaceborne Ka-band circularly polarized antenna elements. The rotation angle of each of the spaceborne Ka-band circularly polarized antenna elements is the same as the phase of the phase shifter connected to it and is n times 90°, where n is 0, 1, 2 or 3 respectively. In the same antenna subarray, the rotation angle difference between any two adjacent spaceborne Ka-band circularly polarized antenna elements is 90°, and / or the phase difference between any two adjacent phase shifters is 90°.

6. The phased array according to claim 5, characterized in that, The power supply transmission structure (2) is a metal layer printed on the lower surface of the dielectric substrate (8).

7. The phased array according to claim 5, characterized in that, The value of N is 4, forming a 64-element Ka-band circularly polarized phased array. The beamwidth of the azimuth and elevation planes of the spaceborne Ka-band circularly polarized antenna element is 113°, the axial ratio within the beamwidth range is less than 3dB, and the horizontal beamwidth is 18° when scanning ±55°. The array gain of the 64-element Ka-band circularly polarized phased array is 23.12dB, the horizontal beamwidth is 12°, and the sidelobe level is 13.2dB when in phase and at equal amplitude.

Images