Dual-band oblique polarization common-aperture array antenna based on tight coupling effect

Abstract

The invention provides a dual-band oblique polarization common-caliber array antenna based on a tight coupling effect. The dual-band oblique polarization common-caliber array antenna comprises a dielectric substrate, a low-frequency antenna, a high-frequency antenna and a metal floor which are perpendicular to one another, the low-frequency antenna comprises a low-frequency modification dipole, a low-frequency feed balun and a low-frequency metal wide-angle impedance matching layer, and the high-frequency antenna comprises a high-frequency modification dipole, a high-frequency feed balun and a high-frequency metal wide-angle impedance matching layer. The design of the common-caliber array antenna is realized in a mode that the dual-band antenna is vertically inserted and the metal floor is shared. The antenna has the advantages of ultra wide band, beam scanning and oblique polarization, and can be used for broadband radar wireless communication.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and in particular relates to a dual-band oblique polarization common-aperture array antenna based on a tight coupling effect. Background Art

[0002] With the rapid development of wireless communication systems and the increasing requirements for antenna functions, communication systems require multiple antennas to independently transmit and receive signals. In order to realize the multiple functions of antennas in a limited space, multiple antennas often adopt a co-aperture design method. Co-aperture technology is to place multiple antennas in a limited space, reduce the mutual coupling interference between antennas of different frequencies through reasonable spatial layout, and realize the functions of each antenna under the same physical aperture. According to the structural characteristics of co-aperture antennas, co-aperture antennas can be divided into the following types: The first type is based on the high- and low-frequency sparse array combination structure. The design feature of this structure is to design another different type of antenna in a single antenna unit or a local position of the antenna array with a large enough size. The second type is based on the reuse of partial antenna structures. On the premise of ensuring the normal operation of high-frequency antennas, the entire structure is used as a low-frequency radiation unit to radiate low-frequency electromagnetic waves outward. The third type is based on the special processing structure of low-frequency antennas. By opening a return slot in the low-frequency antenna and other structures, the high-frequency electromagnetic waves generated by the high-frequency antenna can be ensured to pass through the low-frequency antenna, while ensuring the radiation efficiency and achieving the widening of the antenna bandwidth.

[0003] Tightly coupled array antennas are designed to eliminate the inductance component of the floor by introducing a coupling capacitor structure between antenna array units, thereby obtaining a relatively stable impedance within a wide frequency band, thereby achieving a wider antenna operating bandwidth. Compared with traditional broadband Vivaldi antennas, tightly coupled array antennas have advantages in low profile, wide bandwidth and other performance. By utilizing the characteristics of tight coupling to achieve broadband, combined with common aperture technology, and rationally arranging or specially processing antennas in different frequency bands, the performance advantages of the antenna can be further expanded on the basis of obtaining the functions that can be achieved by tightly coupled array antennas, without increasing the aperture size of the antenna.

[0004] Chen Yikai et al. proposed a dual-band broadband strongly coupled array antenna based on a common aperture structure design in their patent application "A dual-band broadband strongly coupled array antenna based on a common aperture structure design" (application number: CN202310185209.9, publication number: CN116093611A). The antenna consists of a low-frequency antenna, a high-frequency antenna, and a metal floor. The low-frequency antenna unit is subjected to high-frequency wave transmission treatment so that it does not hinder the passage of high-frequency electromagnetic waves when the low-frequency antenna is working. The advantage of this method is that it broadens the antenna bandwidth without loading resistive materials. However, the disadvantage is that the polarization mode is single and the scanning angle is narrow.

[0005] Yan Jianjie et al. proposed a dual-band co-aperture phased array antenna with wide bandwidth and angular scanning in their patent application "A dual-band co-aperture phased array antenna with wide bandwidth and angular scanning" (application number: CN202210192834.1, publication number: CN114552238A). The antenna consists of a low-frequency band antenna unit, no less than 2 high-frequency band antenna units and a metal reflector. The advantage of this method is that it can generate orthogonal polarization components under the same aperture and meet the requirements of large-angle scanning at the same time, but its disadvantage is that the bandwidth that can be achieved by the array unit is relatively narrow. Summary of the invention

[0006] The purpose of the present invention is to address the deficiencies in the prior art and propose a dual-band slant polarization co-aperture array antenna based on a tight coupling effect, which is used to solve the problems of narrow bandwidth, small scanning angle and single polarization mode of the existing co-aperture antenna.

[0007] The specific idea for achieving the purpose of the present invention is: using the tightly coupled array antenna to achieve the characteristics of wide-angle scanning within a broadband, combined with the co-aperture antenna layout method, the low-frequency antenna and the high-frequency antenna dielectric plate are vertically inserted, and the feed network structure of the low-frequency antenna and the overall structure of the high-frequency antenna are interlaced, thereby realizing the independent working state of the low-frequency antenna and the high-frequency antenna. By rotating the co-aperture unit 45° and then arranging the planar array, the dual-slant polarization working state is realized, ensuring that the antenna has polarization components in both the horizontal and vertical directions within a wider working frequency band.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A dual-band slant polarization co-aperture array antenna based on a tight coupling effect, wherein the co-aperture antenna unit comprises a low-frequency antenna, a high-frequency antenna and a metal floor which are vertically inserted; the low-frequency antenna and the high-frequency antenna work independently of each other, and the co-aperture antenna unit is rotated to form an array, so as to realize dual slant polarization of the antenna in a wide frequency band.

[0010] In one embodiment, the low-frequency antenna has an impedance bandwidth of 4:1 frequency multiplication, ranging from 1.5-6.0 GHz, the high-frequency antenna has an impedance bandwidth of 3.5:1 frequency multiplication, ranging from 6.0-21.0 GHz, and the co-aperture array antenna can achieve dual slant polarization within 14:1 frequency multiplication, ranging from 1.5-21.0 GHz.

[0011] In one embodiment, the co-aperture antenna units are rotated 45° to form a dual slant polarization working state.

[0012] In one embodiment, the co-aperture antenna unit is a periodic unit structure simulating an infinite array, and one co-aperture antenna unit includes one low-frequency antenna unit and 3×3 high-frequency antenna units.

[0013] In one embodiment, the low frequency antenna comprises a low frequency dielectric substrate, one side of the low frequency dielectric substrate is printed with a connected low frequency modified dipole and a low frequency feed balun floor, and the other side is printed with a low frequency feed balun;

[0014] The high-frequency antenna comprises a high-frequency dielectric substrate, one side of which is printed with a high-frequency shaped dipole and a high-frequency feeding balun floor connected to each other, and the other side of which is printed with a high-frequency feeding balun.

[0015] In one embodiment, a low-frequency metal wide-angle impedance matching layer is also printed on the one side of the low-frequency dielectric substrate, and the low-frequency metal wide-angle impedance matching layer is used to improve the impedance matching during wide-angle scanning, and is located between the two arms of the low-frequency modified dipole in the vertical projection plane;

[0016] A high-frequency metal wide-angle impedance matching layer is also printed on one side of the high-frequency dielectric substrate. The high-frequency metal wide-angle impedance matching layer is used to improve impedance matching during wide-angle scanning and is located between the two arms of the high-frequency modified dipole in the vertical projection plane.

[0017] In one embodiment, a low-frequency coupling sheet is also printed on the other side of the low-frequency dielectric substrate, and the low-frequency coupling sheet has an overlapping portion with the low-frequency modified dipole in a vertical projection plane to form a capacitive coupling structure for widening the antenna bandwidth;

[0018] A high-frequency coupling sheet is also printed on the other side of the high-frequency dielectric substrate. The high-frequency coupling sheet has an overlapping portion with the high-frequency modified dipole in a vertical projection plane to form a capacitive coupling structure for widening the antenna bandwidth.

[0019] In one embodiment, it is defined that the low-frequency antenna is located in the yz plane, the high-frequency antenna is located in the xz plane, and the metal floor is located in the xy plane; then the low-frequency shaped dipole and the high-frequency shaped dipole are shaped by the following formula:

[0020]

[0021] Where t is a parameter, z(t) represents the horizontal coordinate of the modified dipole in the projection plane, y(t) represents the vertical coordinate of the modified dipole in the projection plane, and x(t) represents the coordinate in the direction perpendicular to the projection plane; v s is the horizontal coordinate of the starting point in the projection plane, v e is the abscissa of the end point in the projection plane, h is the height difference between the start point and the end point, k is the slope of the curve, and the projection plane is the plane where the low-frequency shaped dipole and the high-frequency shaped dipole are respectively printed on the dielectric plate.

[0022] In one embodiment, the low-frequency dielectric substrate is hollowed out at intervals and vertically inserted with a plurality of high-frequency antennas.

[0023] In one embodiment, the low-frequency feed balun and the low-frequency feed balun floor together constitute a low-frequency improved Marchand balun, and the high-frequency feed balun and the high-frequency feed balun floor together constitute a high-frequency improved Marchand balun. By digging holes on the feed floor to introduce short-circuit branches and introducing open-circuit branches on the feed side, multiple resonance points are introduced within the antenna operating frequency band.

[0024] In one embodiment, the low-frequency feeding balun is located in the gap between two adjacent high-frequency antennas in the y direction and has no contact with the high-frequency antennas.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] First, since the present invention is based on tightly coupled dipole units and the principle of widening the antenna bandwidth by generating coupling capacitance between array elements of tightly coupled array antennas, the low-frequency antenna and the high-frequency antenna each operate within a wider operating frequency band.

[0027] Second, since the present invention adds a metal wide-angle impedance matching layer above the low-frequency and high-frequency radiators, it can obtain a more stable impedance when the array antenna scans at a large angle, thereby improving the matching effect during large-angle scanning to a certain extent and enhancing the antenna phase scanning capability.

[0028] Third, since the present invention staggers the positions of the low-frequency antenna and the high-frequency antenna by vertical insertion, the low-frequency antenna and the high-frequency antenna can work independently; by rotating the common-aperture units, dual-slant polarization of the antenna can be achieved in a wide frequency band. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0030] Figure 2 It is a schematic diagram of the low-frequency antenna structure of the present invention.

[0031] Figure 3 It is a schematic diagram of the high-frequency antenna structure of the present invention.

[0032] Figure 4 It is a schematic diagram of the model after the units are arranged in the simulation experiment of the present invention.

[0033] Figure 5 It is the port active voltage standing wave ratio of the low-frequency unit of the common-aperture array unit when the D-plane is scanned under the infinite array condition in the simulation experiment of the present invention.

[0034] Figure 6 It is the port active voltage standing wave ratio of the high frequency unit of the common aperture array unit in the simulation experiment of the present invention when the D-plane is scanned under the condition of infinite array.

[0035] Figure 7 It is the port active voltage standing wave ratio of the low-frequency unit of the common-aperture array unit when the D-plane is scanned under the condition of a finite array in the simulation experiment of the present invention.

[0036] Figure 8 It is the port active voltage standing wave ratio of the high frequency unit of the common aperture array unit in the simulation experiment of the present invention when the D-plane is scanned under the condition of a finite array.

[0037] Fig. 9 It is the radiation pattern of the finite large common aperture array low frequency antenna at 1.5 GHz, 3.5 GHz and 6 GHz in the simulation experiment of the present invention.

[0038] Fig.10 It is the radiation pattern of the finite large common aperture array high frequency antenna at 6 GHz, 13.5 GHz and 21 GHz in the simulation experiment of the present invention.

[0039] Fig.11 It is the polarization isolation degree during D-plane scanning of a finite common aperture array in the simulation experiment of the present invention.

[0040] In the figure: 1. low-frequency shaped dipole; 2. low-frequency coupling plate; 3. low-frequency feed balun; 4. low-frequency feed balun floor; 5. low-frequency metal wide-angle impedance matching layer; 6. low-frequency dielectric substrate; 8. low-frequency feed port; 9. metal floor; 11. high-frequency shaped dipole; 12. high-frequency coupling plate; 13. high-frequency feed balun; 14. high-frequency feed balun floor; 15. high-frequency metal wide-angle impedance matching layer; 16. high-frequency feed port; 17. high-frequency dielectric substrate. DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0042] Reference Figure 1 , the overall structure of the common-aperture array antenna unit of the present invention is further described in detail.

[0043] The co-aperture antenna unit of the present invention comprises a vertically inserted low-frequency antenna 18, a high-frequency antenna 19, and a metal floor 9. The low-frequency antenna 18 and the high-frequency antenna 19 work independently, and by rotating the co-aperture antenna unit, the antenna can achieve dual slant polarization in a wide frequency band.

[0044] For example, the low-frequency antenna 18 of the present invention has an impedance bandwidth of 4:1 frequency multiplication (1.5-6.0 GHz), and the high-frequency antenna 19 has an impedance bandwidth of 3.5:1 frequency multiplication (6.0-21.0 GHz). Then the common-aperture array antenna can achieve dual slant polarization within 14:1 frequency multiplication (1.5-21.0 GHz).

[0045] The low-frequency antenna 18 of the present invention is a periodic unit structure, and forms a co-aperture antenna unit with the high-frequency antenna 19 by cutting and translating. Therefore, the co-aperture antenna unit is a periodic unit structure in the case of simulating an infinite array. In the embodiment of the present invention, a co-aperture antenna unit includes a low-frequency antenna unit 18 and 3×3 high-frequency antenna units 19.

[0046] Reference Figure 2 and Figure 3 , the overall structure of the low-frequency antenna 18 and the high-frequency antenna 19 of the present invention is further described in detail.

[0047] like Figure 2 , 3 As shown, the low-frequency antenna 18 in the present invention includes a low-frequency modified dipole 1, a low-frequency coupling plate 2, a low-frequency feeding balun 3, a low-frequency feeding balun floor 4, a low-frequency metal wide-angle impedance matching layer 5, a low-frequency dielectric substrate 6, and a low-frequency feeding port 8. The low-frequency antenna 18 is fed via the low-frequency feeding port 8. The low-frequency modified dipole 1, the low-frequency metal wide-angle impedance matching layer 5 and the low-frequency feeding balun floor 4 are printed on one side of the low-frequency dielectric substrate 6, and the low-frequency coupling plate 2 and the low-frequency feeding balun 3 are printed on the other side of the low-frequency dielectric substrate 6.

[0048] The high-frequency antenna 19 includes a high-frequency shaped dipole 11, a high-frequency coupling plate 12, a high-frequency feeding balun 13, a high-frequency feeding balun floor 14, a high-frequency metal wide-angle impedance matching layer 15, a high-frequency dielectric substrate 17, and a high-frequency feeding port 16. The high-frequency antenna 19 is fed via the high-frequency feeding port 16. The high-frequency shaped dipole 11, the high-frequency metal wide-angle impedance matching layer 15, and the high-frequency feeding balun floor 14 are printed on one side of the high-frequency dielectric substrate 17, and the high-frequency coupling plate 12 and the high-frequency feeding balun 13 are printed on the other side of the high-frequency dielectric substrate 17.

[0049] Furthermore, the frequency-fed balun 3 is located in the gap between two adjacent high-frequency antennas 19 in the y direction and has no contact with the high-frequency antennas 19 .

[0050] For example, in the present invention, the material of the low-frequency dielectric substrate 6 is Rogers RT / duroid 5880 (tm), and the relative dielectric constant ε r =2.2, thickness is 0.508 mm, the material of the high frequency dielectric substrate 17 is Rogers RO 4350(tm), relative dielectric constant ε r =3.66, thickness is 0.254mm.

[0051] Among them, the radiation arm parts of the low-frequency shaped dipole 1 and the high-frequency shaped dipole 11 are subjected to third-order shaping processing by formula 1, which can reduce the impedance value corresponding to the resonance point of the tightly coupled dipole, which is beneficial to the matching design of the radiator and the feeding balun, and widens the antenna bandwidth. At the same time, the low-frequency coupling plate 2 and the high-frequency coupling plate 12 provide compensation capacitance for the low-frequency shaped dipole 1 and the high-frequency shaped dipole 11, respectively, which is beneficial to broadband impedance matching, further expanding the antenna bandwidth to low frequency, and realizing broadband working characteristics. Specifically, the low-frequency coupling plate 2 has an overlapping portion with the low-frequency shaped dipole 1 in the vertical projection plane, forming a capacitive coupling structure to widen the antenna bandwidth. The high-frequency coupling plate 12 has an overlapping portion with the high-frequency shaped dipole 11 in the vertical projection plane, forming a capacitive coupling structure to widen the antenna bandwidth.

[0052] Furthermore, the low-frequency feeding balun 3 and the low-frequency feeding balun floor 4 together constitute a low-frequency improved Marchand balun, and the high-frequency feeding balun 13 and the high-frequency feeding balun floor 14 together constitute a high-frequency improved Marchand balun. By digging holes on the feeding floor to introduce short-circuit branches and introducing open-circuit branches on the feeding side, multiple resonance points can be introduced within the antenna operating frequency band, ensuring balanced feeding of the radiator while achieving broadband operating characteristics of the feeding network. At the same time, the multi-section gradient microstrip feed lines in the low-frequency feeding balun 3 and the high-frequency feeding balun 13 can transform the dipole input impedance into 50Ω, which is convenient for connecting the coaxial port used in the processing.

[0053] According to this embodiment, the low-frequency shaped dipole 1 is connected to the low-frequency feeding balun floor 4, and the high-frequency shaped dipole 11 is connected to the high-frequency feeding balun floor 14. The integrated design saves space and reduces the complexity of the design. The low-frequency feeding port 8 is located below the low-frequency dielectric substrate 5, one side of which is connected to the low-frequency feeding balun floor 4, and one side is connected to the low-frequency feeding balun 3; the high-frequency feeding port 16 is located below the high-frequency dielectric substrate 17, one side of which is connected to the high-frequency feeding balun floor 14, and one side of which is connected to the high-frequency feeding balun 13. It is worth noting that, considering the actual application situation, the low-frequency antenna part under the metal floor 9 is at the same height as the high-frequency antenna part, and there is no need to add a special support structure under the antenna, which is conducive to the subsequent installation and fixation of the antenna.

[0054] The low-frequency metal wide-angle impedance matching layer 5 of the present invention is used to improve the impedance matching during wide-angle scanning, and is located between the two arms of the low-frequency modified dipole 1 in the vertical projection plane. The high-frequency metal wide-angle impedance matching layer 15 is used to improve the impedance matching during wide-angle scanning, and is located between the two arms of the high-frequency modified dipole 11 in the vertical projection plane.

[0055] Furthermore, the present invention embeds three pairs of evenly spaced metal strips above the low-frequency shaped dipole 1 to form a low-frequency metal wide-angle impedance matching layer 5, and embeds three pairs of evenly spaced metal strips above the high-frequency shaped dipole 11 to form a high-frequency metal wide-angle impedance matching layer 15. This can stabilize the impedance change of the antenna during large-angle scanning without increasing the antenna cross-section, thereby improving the antenna's large-angle phase scanning capability.

[0056] Further, referring to the arrangement method of the tightly coupled dual-polarized antenna, in some embodiments of the present invention, the low-frequency dielectric substrate 6 is hollowed out 7 at three locations with an interval of 7 mm to reserve sufficient space for vertical insertion with the high-frequency antenna 19.

[0057] Furthermore, the low-frequency modified dipole radiation arm heights in this embodiment are l1=1.5mm, l2=2.5mm, l3=3mm, the low-frequency coupling plate 2 width w1=4mm, and the low-frequency antenna unit size is L=21mm. The high-frequency modified dipole radiation arm heights are l4=0.3mm, l5=1.4mm, l6=1.8mm, the high-frequency coupling plate 12 width is 1mm, and the high-frequency antenna unit size is l=7mm.

[0058] Furthermore, the metal floor 9 in this embodiment is grooved 10 at the position of the dielectric substrate where the low-frequency antenna 18 and the high-frequency antenna 19 are located. The tiny grooves will not damage the overall radiation structure. By reserving sufficient gaps, it is possible to avoid electrical connection between the feeding network parts of the low-frequency antenna and the high-frequency antenna and the metal floor 9, thereby affecting the normal operation of the antenna.

[0059] like Figure 4 In this embodiment, the low-frequency antenna 18 and the high-frequency antenna 19 are vertically inserted through the dielectric substrate to form a tightly coupled dual-band common-aperture antenna unit. The radiation structure of the low-frequency antenna is located above the high-frequency antenna, and all feeding parts of the low-frequency antenna are located in the empty part between adjacent high-frequency antennas. The design of this compact feeding network can ensure efficient use of space under the same aperture. At the same time, the dual-band antenna has no other overlapping structures except the dielectric substrate. After the tightly coupled dual-band common-aperture antenna unit is rotated 45°, multiple tightly coupled dual-band common-aperture antenna units in the present invention are arrayed to form a 4×3 dual-band oblique polarization common-aperture array antenna based on the tight coupling effect, which is composed of 11 complete low-frequency feeding units and 288 high-frequency feeding units.

[0060] According to the above structure, the present invention has the advantages of broadband, oblique polarization and large-angle phase scanning. It can be used in the 1.5-21.0GHz band when working in different frequency bands. Within the working band, it can achieve D-plane ±45° phase scanning capability, which is suitable for broadband phased array antenna beam electronic control scanning.

[0061] The following is a further description of the technical effects of the present invention in combination with simulation experiments:

[0062] When the dual-band oblique polarization common-aperture antenna unit modeled and simulated by the commercial simulation software HFSS2022R1 of the present invention is working, the active standing wave ratio of the port of the low-frequency antenna unit when scanning on the D plane is as follows: Figure 5 shown. Figure 5 The horizontal axis is the frequency value in GHz, and the vertical axis is the active standing wave ratio. The square solid line is the active standing wave ratio curve when the low-frequency antenna is side-firing, and the triangular dotted line is the active standing wave ratio curve when the low-frequency antenna D-plane scans 45°. It can be seen from the figure that when the average standing wave ratio is required to be less than 3, the low-frequency unit of the dual-band oblique polarization common aperture antenna of the present invention has an impedance bandwidth of 4:1 (1.5-6.0GHz) within a 45-degree scanning range.

[0063] When the dual-band oblique polarization common-aperture antenna unit modeled and simulated by the commercial simulation software HFSS2022R1 of the present invention is working, the result of the active standing wave ratio of the port of the high-frequency antenna unit when scanning on the D plane is as follows: Figure 6 shown. Figure 6 The horizontal axis is the frequency value in GHz, and the vertical axis is the active standing wave ratio. The square solid line is the active standing wave ratio curve when the low-frequency antenna is side-firing, and the triangular dotted line is the active standing wave ratio curve when the low-frequency antenna D-plane scans 45°. It can be seen from the figure that when the average standing wave ratio is required to be less than 3, the low-frequency unit of the dual-band oblique polarization common aperture antenna of the present invention has an impedance bandwidth of 3.5:1 (6.0-21.0GHz) within a 45-degree scanning range.

[0064] The dual-band oblique polarization common-aperture antenna units based on the tight coupling effect of the present invention are arrayed in the form of 4×3 to achieve wide-angle beam scanning.

[0065] When the dual-band oblique polarization common aperture antenna array modeled and simulated by the commercial simulation software HFSS2022R1 is working, the active standing wave ratio of the port of the central unit of the low-frequency antenna array is as follows when scanning on the D plane: Figure 7 shown. Figure 7 The horizontal axis is the frequency value in GHz, and the vertical axis is the active standing wave ratio. The square solid line is the active standing wave ratio curve of the low-frequency antenna center unit when it is side-firing, and the triangular dotted line is the active standing wave ratio curve of the low-frequency antenna center unit when the D plane scans 45°. It can be seen from the figure that when the average standing wave ratio is required to be less than 3, the dual-band oblique polarization common aperture antenna low-frequency array of the present invention has an impedance bandwidth of 4:1 (1.5-6.0GHz) within a 45-degree scanning range.

[0066] When the dual-band oblique polarization common aperture antenna array modeled and simulated by the commercial simulation software HFSS2022R1 is working, the active standing wave ratio of the port of the central unit of the high-frequency antenna array is as follows when scanning on the D plane: Figure 8 shown. Figure 8 The horizontal axis is the frequency value in GHz, and the vertical axis is the active standing wave ratio. The square solid line is the active standing wave ratio curve of the high-frequency antenna center unit when it is side-firing, and the triangular dotted line is the active standing wave ratio curve of the high-frequency antenna center unit when the D plane scans 45°. It can be seen from the figure that when the average standing wave ratio is required to be less than 3, the dual-band oblique polarization common aperture antenna high-frequency array of the present invention has an impedance bandwidth of 3.5:1 (6.0-21.0GHz) within a 45-degree scanning range.

[0067] When the dual-band oblique polarization common-aperture antenna array modeled and simulated by the commercial simulation software HFSS2022R1 is working, the radiation patterns of the low-frequency array at 1.5 GHz, 3.5 GHz, and 6 GHz are as follows: Fig. 9 As shown, Fig. 9 The horizontal axis is the angle with the z-axis, in deg, and the vertical axis is the antenna gain, in dBi. The square solid line is the radiation pattern curve of the low-frequency antenna when it is sideways, the circular dotted line is the radiation pattern curve of the low-frequency antenna when it scans -45° on the D plane, and the triangular dotted line is the radiation pattern curve of the low-frequency antenna when it scans 45° on the D plane. It can be seen from the figure that the low-frequency finite array beam pointing accuracy of the embodiment of the present invention is good, and large-angle phase scanning can be achieved within the working frequency band.

[0068] When the dual-band oblique polarization common aperture antenna array modeled and simulated by the commercial simulation software HFSS2022R1 of the present invention is working, the radiation patterns of the high-frequency array at 6 GHz, 13.5 GHz, and 21 GHz are as follows: Fig.10 As shown, Fig.10 The horizontal axis is the angle with the z-axis, in degrees, and the vertical axis is the antenna gain, in dBi. The square solid line is the radiation pattern curve of the high-frequency antenna when it is sideways, the circular dotted line is the radiation pattern curve of the high-frequency antenna when it scans -45° on the D plane, and the triangular dotted line is the radiation pattern curve of the high-frequency antenna when it scans 45° on the D plane. It can be seen from the figure that the high-frequency finite array beam pointing accuracy of the embodiment of the present invention is good, and large-angle phase scanning can be achieved within the working frequency band.

[0069] When the dual-band oblique polarization common aperture antenna array obtained by modeling and simulating the present invention using the commercial simulation software HFSS2022R1 works, the polarization isolation between the low-frequency antenna center unit and the high-frequency antenna unit in the common aperture unit area is as follows: Fig.11 As shown, Fig.11The horizontal axis is the frequency value in GHz, the vertical axis is the polarization isolation in dB, the square solid line is the polarization isolation curve between the low-frequency antenna and the high-frequency antenna when the antenna is sideways, the circular dotted line is the polarization isolation curve between the low-frequency antenna and the high-frequency antenna when the antenna D plane scans -45°, and the triangular dotted line is the polarization isolation curve between the low-frequency antenna and the high-frequency antenna when the antenna D plane scans 45°. It can be seen from the figure that the polarization isolation between the low-frequency antenna and the high-frequency antenna of the dual-band oblique polarization common aperture antenna of the present invention is better than 22dB when sideways, and the polarization isolation level decreases slightly as the scanning angle increases, and is better than 12dB when the D plane scans ±45°.

[0070] The above simulation results show that compared with the prior art, the present invention saves the physical space of the antenna, improves the antenna aperture efficiency, and achieves the effect of wide-band and wide-angle scanning of the array antenna by vertically inserting the dielectric substrates to treat the dual-band antennas in the same aperture while ensuring that the low-frequency antenna and the high-frequency antenna work independently without interfering with each other. The present invention has the advantages of broadband, wide-angle scanning, oblique polarization, etc., and has certain application value for broadband radar wireless communication systems.

Claims

1. A dual-band slant-polarization common-aperture array antenna based on tight coupling effect, characterized in that: The common-aperture antenna unit comprises a low-frequency antenna (18), a high-frequency antenna (19) and a metal floor (9) which are vertically inserted; the low-frequency antenna (18) and the high-frequency antenna (19) work independently of each other, and the common-aperture antenna unit is rotated to achieve dual slant polarization of the antenna in a wide frequency band.

2. According to the dual-band slant-polarization common-aperture array antenna based on tight coupling effect in claim 1, it is characterized in that: The low-frequency antenna (18) has an impedance bandwidth of 4:1 frequency doubling, ranging from 1.5 to 6.0 GHz, the high-frequency antenna (19) has an impedance bandwidth of 3.5:1 frequency doubling, ranging from 6.0 to 21.0 GHz, and the common-aperture array antenna can achieve dual slant polarization within a 14:1 frequency doubling, ranging from 1.5 to 21.0 GHz.

3. According to the dual-band slant-polarization common-aperture array antenna based on tight coupling effect in claim 1, it is characterized in that: The co-aperture antenna units are rotated 45° to form a dual slant polarization working state.

4. According to the dual-band slant-polarization common-aperture array antenna based on tight coupling effect in claim 1, it is characterized in that: The co-aperture antenna unit is a periodic unit structure simulating an infinite array, and one co-aperture antenna unit comprises a low-frequency antenna unit (18) and 3×3 high-frequency antenna units (19).

5. The dual-band slant-polarization common-aperture array antenna based on tight coupling effect according to claim 1, characterized in that: The low-frequency antenna (18) comprises a low-frequency dielectric substrate (6), one side of the low-frequency dielectric substrate (6) is printed with a connected low-frequency shaped dipole (1) and a low-frequency feeding balun floor (4), and the other side of the low-frequency dielectric substrate (6) is printed with a low-frequency feeding balun (3); The high-frequency antenna (19) comprises a high-frequency dielectric substrate (17), one side of the high-frequency dielectric substrate (17) is printed with a high-frequency shaped dipole (11) and a high-frequency feeding balun floor (14) connected to each other, and the other side of the high-frequency dielectric substrate (17) is printed with a high-frequency feeding balun (13).

6. The dual-band slant-polarization common-aperture array antenna based on tight coupling effect according to claim 5, characterized in that: A low-frequency metal wide-angle impedance matching layer (5) is also printed on one side of the low-frequency dielectric substrate (6), and the low-frequency metal wide-angle impedance matching layer (5) is used to improve the impedance matching condition during wide-angle scanning, and is located between the two arms of the low-frequency modified dipole (1) in the vertical projection plane; A high-frequency metal wide-angle impedance matching layer (15) is also printed on one side of the high-frequency dielectric substrate (17). The high-frequency metal wide-angle impedance matching layer (15) is used to improve impedance matching during wide-angle scanning and is located between two arms of the high-frequency shaped dipole (11) in the vertical projection plane.

7. The dual-band slant-polarization common-aperture array antenna based on tight coupling effect according to claim 5, characterized in that: A low-frequency coupling sheet (2) is also printed on the other side of the low-frequency dielectric substrate (6), and the low-frequency coupling sheet (2) has an overlapping portion with the low-frequency modified dipole (1) in a vertical projection plane, forming a capacitive coupling structure for widening the antenna bandwidth; A high-frequency coupling sheet (12) is also printed on the other side of the high-frequency dielectric substrate (17); the high-frequency coupling sheet (12) has an overlapping portion with the high-frequency shaped dipole (11) in a vertical projection plane, forming a capacitive coupling structure for widening the antenna bandwidth.

8. The dual-band slant-polarization common-aperture array antenna based on tight coupling effect according to claim 5, characterized in that: It is defined that the low-frequency antenna (18) is located in the yz plane, the high-frequency antenna (19) is located in the xz plane, and the metal floor (9) is located in the xy plane; then the low-frequency shaped dipole (1) and the high-frequency shaped dipole (11) are shaped by the following formula: Where t is a parameter, z(t) represents the horizontal coordinate of the modified dipole in the projection plane, y(t) represents the vertical coordinate of the modified dipole in the projection plane, and x(t) represents the coordinate in the direction perpendicular to the projection plane; v s is the horizontal coordinate of the starting point in the projection plane, v e is the abscissa of the end point in the projection plane, h is the height difference between the start point and the end point, and k is the slope of the curve. The projection plane is the plane where the low-frequency shaped dipole (1) and the high-frequency shaped dipole (11) are respectively printed on the dielectric plate.

9. The dual-band slant-polarization common-aperture array antenna based on tight coupling effect according to claim 5, characterized in that: The low-frequency feeding balun (3) and the low-frequency feeding balun floor (4) together constitute a low-frequency improved Marchand balun, and the high-frequency feeding balun (13) and the high-frequency feeding balun floor (14) together constitute a high-frequency improved Marchand balun. By digging holes in the feeding floor to introduce short-circuit branches and introducing open-circuit branches on the feeding side, multiple resonance points are introduced within the antenna working frequency band.

10. The dual-band slant-polarization common-aperture array antenna based on tight coupling effect according to claim 1, characterized in that: The low-frequency feeding balun (3) is located in the gap between two adjacent high-frequency antennas (19) in the y direction and has no contact with the high-frequency antennas (19).

Images