Ferromagnetic-loaded large-curvature wing conformal strong-coupling ultra-wideband one-dimensional phased array antenna

Abstract

The present invention discloses a ferrite-loaded large-curvature wing conformal strongly-coupled ultra-wideband one-dimensional phased array antenna, which includes a wing carrier contour, a strongly-coupled conformal dipole linear array, a tapered microstrip feeding balun, a segmented ferrite, a fixed substrate, a metal reflection floor, and a microstrip power divider; the strongly-coupled conformal dipole linear array operates in the vertical polarization state to achieve complete conformal to the wing carrier contour; the upper part of the tapered microstrip feeding balun is welded to the dipole element, and the lower part is embedded in the fixed substrate; the segmented ferrite is located at a specific position between the wing carrier contour and the reflection floor to achieve excellent characteristics of expanding the antenna bandwidth; the line length of the microstrip power divider is specially designed to achieve the control of the beam pointing; through the careful design of the strongly-coupled dipole linear array and the microstrip power divider, the present invention achieves the complete conformal characteristic, and loads the ferrite material to realize excellent radiation performances such as ultra-wideband and wide-angle scanning.

Description

Technical Field

[0001] The present invention belongs to the technical field of antenna engineering, and particularly relates to a ferrite-loaded large-curvature wing conformal strongly coupled ultra-wideband one-dimensional phased array antenna. Background Art

[0002] With the continuous development of radio electronics technology, especially the increasingly stringent requirements for antenna performance in the military field, independent single antennas can no longer meet the needs, and phased array antennas have thus emerged. In recent years, phased array antennas have been applied in more and more comprehensive fields, such as radar systems, wireless communication systems, and military electronic platforms, and the performance requirements for them have also become more and more.

[0003] However, for some high-speed platforms, such as various aircraft, due to considerations of aerodynamic layout and other factors, it is sometimes difficult to apply planar antenna structures. At this time, conformal antennas with equally good electrical performance can play their advantages of low profile and easy platform integration. The conformal layout can greatly reduce the aerodynamic drag brought by the traditional antenna layout to the platform, improve the installability of the antenna and reduce the burden on the platform. At the same time, it can also make full use of the platform space, increase the antenna aperture area, and reduce the scanning blind area. In addition, the conformal layout can also effectively reduce the radar cross section of the carrier platform and improve the stealth performance. Conformal phased array antennas with ultra-wideband wide-angle scanning capabilities have now become the focus of research by scientists in various countries.

[0004] Based on the new requirements for phased array antennas proposed above, an antenna that achieves ultra-wideband by strengthening the capacitive coupling between array elements, namely a strongly coupled antenna, has emerged. Through the strong capacitive coupling between elements, such an antenna not only reduces the lateral and longitudinal dimensions of the elements, but also has characteristics such as low profile, lightweight, ultra-wide frequency band, wide-angle scanning, and low cross-polarization. In recent years, some studies have taken resistive material loading as a new technical approach to improve the working bandwidth of antennas. In the Chinese patent "A Decade-Bandwidth Dual-Polarized Strongly Coupled Phased Array Antenna with Resistive Material Loading" with the application number CN202210384772.4, by loading interdigital resistive frequency selective surfaces, the adverse reflections caused by in-band common-mode resonance are absorbed, and a decade-bandwidth ultra-wideband antenna operating in the range of 0.2 - 2 GHz is achieved, but its profile height has not been improved and is as high as 0.63 times the high-frequency wavelength. In the Chinese patent "Ferrite-Loaded Dual-Polarized Low-Profile Strongly Coupled Ultra-Wideband Phased Array Antenna" with the application number CN202110120853.9, by loading ferrite materials, while the antenna achieves a decade-bandwidth ultra-wideband, its profile height is only 0.42 times the high-frequency wavelength, but the planar structure of the antenna makes it difficult to be applied to wing carrier platforms and is not conducive to practical applications. In the Chinese patent "A Wide-Angle Conformal Linear Phased Array Antenna Based on FSS Structure" with the application number CN201911278146.1, the antenna can be conformal on the structure surface, greatly reducing the space volume occupied by the antenna, and can also ensure good radiation characteristics and high directivity. However, its working bandwidth is narrow and it is not conducive to practical applications.

[0005] The above patents have their own characteristics in terms of antenna resistive material loading and conformal design, but still difficult to meet the comprehensive challenges of antenna bandwidth, antenna structure, profile height and other factors in practical engineering applications. Therefore, it has very important practical engineering significance to conduct research on conformal antennas with resistive material loading to obtain higher performance antenna technical indicators such as high gain, ultra-wideband, and conformal on large curvature carriers. Summary of the Invention

[0006] Aiming at the deficiencies in the prior art, the ferrite-loaded large-curvature wing conformal strongly coupled ultra-wideband one-dimensional phased array antenna provided by the present invention solves the problems of narrow antenna bandwidth, difficult conformal, and high profile in existing phased array antennas.

[0007] To achieve the above-mentioned invention object, the technical solution adopted by the present invention is: a ferrite-loaded large-curvature wing conformal strong-coupling ultra-wideband one-dimensional phased array antenna, including a wing carrier contour, a strong-coupling conformal dipole linear array, a tapered microstrip feed balun, a segmented ferrite, a fixed substrate, a metal reflection floor, and a microstrip power divider; the wing carrier contour is formed by bending a dielectric into the shape of a wing; the strong-coupling conformal dipole linear array operates in the vertical polarization state and is completely conformal to the wing contour; the upper part of the tapered microstrip feed balun is welded to the strong-coupling conformal dipole unit, and the lower part is embedded on the metal reflection floor of the integrated microstrip power divider.

[0008] Furthermore, the front surface of the tapered microstrip feed balun adopts a metal structure in the shape of a tapered line, which is printed on the front side of the dielectric substrate, and realizes the conversion from unbalanced feeding to balanced feeding through the tapered microstrip line.

[0009] Furthermore, the strong-coupling conformal dipole linear array is conformal on the upper surface of the wing contour and consists of a linear array composed of six dipole units in two upper and lower layers. Metal patches are provided at the ends of the dipole units to enhance capacitive coupling, further broadening the antenna bandwidth. The metal patches are conformal on the lower surface of the wing contour, and the dipole units at the edges are subjected to additional extension processing to improve the truncation effect, realizing an ultra-wide operating bandwidth. The middle dipole units are directly connected to overcome the problem of difficult conformal at the tip of the large-curvature wing.

[0010] Furthermore, the segmented ferrite is composed of eight specially designed ferrite blocks, which are symmetrically distributed in two upper and lower layers and are located at specific positions between the antenna and the metal reflection floor. The combined structure not only avoids the tapered microstrip feed balun but also realizes the excellent characteristic of expanding the antenna bandwidth.

[0011] Furthermore, the metal reflection floor is in a wedge shape and is spliced by two symmetric rectangular metal plates up and down. It is located in the middle of the entire wing contour. The wedge shape is beneficial to the beam pointing to the front end of the wing; the fixed substrate is located above the metal floor and is provided with an installation groove, and the dielectric substrate of the tapered microstrip feed balun is fixed in the installation groove.

[0012] Furthermore, the microstrip power divider can be regarded as consisting of two parts. One part is two one-to-three power dividers integrated on the upper and lower sides of the metal reflection floor, and the other part is a one-to-two power divider printed on the wing contour. These two parts together constitute a one-to-six power divider, so that the final antenna unit as a whole has only one input port, reducing the processing cost and the antenna volume; among them, the phases of each output port of the one-to-three power divider are different, which can realize the control of the beam pointing; in addition, through reasonable layout and routing, the space of the wing contour is fully utilized.

[0013] In summary, the beneficial effects of the present invention are as follows: The ferrite-loaded large-curvature wing conformal strongly coupled ultra-wideband one-dimensional phased array antenna provided by the present invention uses a tapered microstrip feed balun to convert unbalanced feeding to balanced feeding, achieving antenna feeding within an extremely wide frequency band; the strongly coupled dipole linear array realizes complete conformal to the wing carrier contour. By loading metal patches, the coupling between dipole elements is strengthened, achieving the effect of bandwidth expansion. And by extending the length of the edge dipole elements, the edge truncation effect is overcome. The middle dipole elements are directly connected to overcome the problem of difficult conformal at the tip of the large-curvature wing; the segmented ferrite plays the role of bandwidth expansion and profile reduction through the electromagnetic characteristics of the ferrite itself, and has a simple structure, reducing the processing cost; by designing the length of the metal reflection floor and the wedge angle, the control of the beam direction is realized. The metal reflection floor is composed of two symmetric rectangular metal plates spliced up and down, which is easy to process and makes reasonable use of the space of the wing carrier; by designing the line length of the microstrip power divider and adjusting the phase of each output port of the power divider, the beam scanning direction is further controlled, so that the maximum gain direction is at the tip of the wing, and broadband wide-angle scanning is realized. At the same time, through reasonable layout and routing, finally the antenna unit as a whole has only one input port, reducing the cost and making full use of the space of the wing profile. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 FIG. is a schematic structural diagram of a ferrite-loaded large-curvature wing conformal strongly coupled ultra-wideband one-dimensional phased array antenna unit provided by the present invention.

[0015] Figure 2 FIG. is a schematic diagram of a strongly coupled conformal dipole linear array in an embodiment provided by the present invention.

[0016] Figure 3 FIG. is a schematic diagram of a segmented ferrite in an embodiment provided by the present invention.

[0017] Figure 4 FIG. is a schematic diagram of a fixed substrate and a metal reflection floor in an embodiment provided by the present invention.

[0018] Figure 5 FIG. is a schematic diagram of a microstrip power divider in an embodiment provided by the present invention.

[0019] Figure 6 In the embodiment provided by the present invention Figure 1 The voltage standing wave ratio of all frequency bands at the port when the shown unit scans 0-60 degrees in the azimuth plane (H plane).

[0020] Figure 7 In the embodiment provided by the present invention Figure 1 Comparison of the main polarization gain, cross polarization gain and theoretical gain when the shown unit is side radiating.

[0021] Figure 8 In the embodiments provided by the present invention Figure 1 After the units shown form a 1×8 linear array, the scanning gain patterns and cross-polarization conditions at 0 degrees and 60 degrees at 2 GHz are presented.

[0022] Figure 9 In the embodiments provided by the present invention Figure 1 After the units shown form a 1×8 linear array, the scanning gain patterns and cross-polarization conditions at 0 degrees and 60 degrees at 1 GHz are presented.

[0023] Figure 10 In the embodiments provided by the present invention Figure 1 After the units shown form a 1×8 linear array, the scanning gain patterns and cross-polarization conditions at 0 degrees and 60 degrees at 0.3 GHz are presented.

[0024] Wherein: 1. Wing carrier contour; 2. Strongly coupled conformal dipole linear array; 201. Metal patch; 202. Upper extended metal patch; 203. Lower extended metal patch; 211-216. Strongly coupled conformal dipole units; 3. Gradient microstrip feeding balun; 4. Block-type ferrite; 401-408. Ferrite blocks; 5. Fixed substrate; 501. Upper fixed substrate; 502. Lower fixed substrate; 6. Metal reflection floor; 601. Upper metal reflection floor; 602. Lower metal reflection floor; 7. Microstrip power divider; 701. One-to-two power divider; 702. Upper one-to-three power divider; 703. Lower one-to-three power divider. Detailed implementation manners

[0025] The following describes the detailed implementation manners of the present invention to facilitate the understanding of those skilled in the art of the present technology. However, it should be clear that the present invention is not limited to the scope of the detailed implementation manners. For those ordinary skilled in the art of the present technology, as long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions created using the concept of the present invention are within the scope of protection.

[0026] As Figures 1 to 2 shown, a ferrite-loaded large-curvature wing conformal strongly coupled ultra-wideband one-dimensional phased array antenna unit includes a wing carrier contour 1, a strongly coupled conformal dipole linear array 2, a gradient microstrip feeding balun 3, a block-type ferrite 4, a fixed substrate 5, a metal reflection floor 6, and a microstrip power divider 7; wherein the strongly coupled conformal dipole linear array 2 is composed of six dipole units 211-216.

[0027] The wing carrier profile 1 is composed of two parts: a wing with a large curvature and a backplane. The wing with a large curvature is bent from a Rogers 5880 type substrate material with a relative dielectric constant of 2.2 and a thickness of only 0.254 mm. The backplane is a Rogers 5880 type substrate material with a thickness of 0.508 mm and a relative dielectric constant of 2.2. The two parts are bonded together to form a conformal carrier. The strongly coupled conformal dipole array 2 operates in the vertical polarization state and is completely conformally printed on the upper surface of the wing carrier profile 1. There are three dipole units 211, 212, and 213 in the upper layer, and three dipole units 214, 215, and 216 in the lower layer. Metal patches 201 are provided at the ends of the dipole units to enhance capacitive coupling and further broaden the antenna bandwidth. The metal patches 201 are conformally printed on the lower surface of the wing carrier profile 1. The edge dipole units 211 and 216 are both extended additionally. The upper extended metal patch 202 is printed on the backplane of the wing carrier profile 1, and the lower extended metal patch 203 is printed on the backplane of the wing carrier profile 1. The middle dipole units 213 and 214 are directly connected to overcome the problem of difficult conformal shaping at the tip of the wing with a large curvature.

[0028] The tapered microstrip feed balun 3 is composed of tapered metal microstrip lines printed on a Rogers 5880 type substrate material with a relative dielectric constant of 2.2, realizing the function of converting unbalanced feeding to balanced feeding. Further, it is welded to the strongly coupled conformal dipole unit above, vertically embedded in the mounting groove on the fixed substrate 5 below, and welded to the microstrip power divider 7 integrated on the metal reflector floor 6.

[0029] As Figure 3 shown, the segmented ferrite 4 is composed of eight specially designed ferrite blocks 401 - 408. Four are symmetrically distributed in the upper and lower layers, all parallel to the metal reflector floor 6, and located at specific positions between the wing carrier profile 1 and the metal reflector floor 6. Among them, the ferrite blocks 401, 402, 403, 406, 407, and 408 are completely the same, and the ferrite blocks 404 and 405 are completely the same. The segmented structure avoids the tapered microstrip feed balun 3 and provides a support and fixing structure to exactly support it at the required specific height, realizing the excellent characteristic of expanding the antenna bandwidth.

[0030] As Figure 4 shown, the fixed substrate 5 is formed by bonding two Rogers 5880 type substrate materials 501 and 502 with a thickness of 0.508 mm and a relative dielectric constant of 2.2 into a wedge shape with a specific angle, and is provided with a mounting groove for fixing the tapered microstrip feed balun 3. The metal reflector floor 6 is composed of a metal sheet 601 and a metal sheet 602, in a wedge shape, printed on the lower surface of the fixed substrate 5 to realize the regulation of the beam direction.

[0031] As Figure 5 shown, the microstrip power divider 7 is composed of two parts. One part is a one-to-two power divider 701 printed on the back plate of the wing carrier profile 1, and the other part is a one-to-three power divider 702 integrated on the upper side 601 of the metal reflection floor and a one-to-three power divider 703 integrated on the lower side 602 of the metal reflection floor. These two parts together form a one-to-six power divider, so that there is only one input port in the final entire antenna structure. Further, the line lengths of the one-to-three power dividers 702 and 703 are specially designed, and each output port outputs a specific phase, so that the maximum gain direction points to the wing tip. In addition, through reasonable layout and routing, the microstrip power divider 7 makes full use of the space of the wing profile.

[0032] It should be noted that if the element spacing of the high-frequency elements is equal to half of the wavelength of its highest frequency, then when scanning to any angle (except ±90 degrees) within the entire operating frequency band, grating lobes will not be generated. In order to not reduce the antenna radiation aperture as much as possible while ensuring the antenna performance to achieve a greater gain, in the present invention, the width of the wing carrier profile is 0.5 times the wavelength at the highest frequency of the corresponding frequency band.

[0033] Figure 6 The corresponding active standing wave characteristics of the ports in the H-plane 0-60 degree scanning state of this embodiment are given. It can be seen from the figure that, under the condition that the standing wave ratio requirement is less than 3.0, the ferrite-loaded large-curvature wing conformal strongly coupled ultra-wideband one-dimensional phased array antenna element has an impedance bandwidth of 6.7:1 within the 60-degree scanning range.

[0034] Figure 7 The comparison between the actual co-polarization and cross-polarization gain situations and the theoretical gain situations of all frequencies of the ports in the broadside state of this embodiment is given. It can be seen from the figure that the cross-polarization performance of the antenna can be below -25 dB within the entire operating frequency band, and the average difference between the actual gain value and the theoretical gain value is within 2 dB, having good radiation performance.

[0035] Figure 8 The co-polarization and cross-polarization gain situations at 0 degrees and 60 degrees scanning at the 2 GHz frequency point are given for the 1×8 linear array composed of the ferrite-loaded large-curvature wing conformal strongly coupled ultra-wideband one-dimensional phased array antenna elements provided by this embodiment. It can be seen from the figure that the phased array antenna has a cross-polarization characteristic of more than 15 dB, and the co-polarization of the array can reach 10 dB, and the main-to-side lobe ratio can reach more than 10 dB.

[0036] Figure 9The main polarization and cross-polarization gain conditions of the 1×8 linear array composed of the ferrite-loaded large-curvature wing conformal strong-coupling ultra-wideband one-dimensional phased array antenna elements provided by this embodiment are given under the conditions of 0-degree and 60-degree scanning at the 1 GHz frequency point. It can be seen from the figure that the phased array antenna still has a cross-polarization characteristic of more than 10 dB and a main-to-side lobe ratio of more than 10 dB in the desired direction.

[0037] Figure 10 The main polarization and cross-polarization gain conditions of the 1×8 linear array composed of the ferrite-loaded large-curvature wing conformal strong-coupling ultra-wideband one-dimensional phased array antenna elements provided by this embodiment are given under the conditions of 0-degree and 60-degree scanning at the 0.3 GHz frequency point, and it also has good cross-polarization characteristics and beam scanning characteristics.

Claims

1. Ferrite loaded large curvature wing conformal strongly coupled ultra-wideband one-dimensional phased array antenna, characterized in that: The invention comprises a wing carrier profile (1), a strongly coupled conformal dipole linear array (2), a gradient microstrip feeding balun (3), a block ferrite (4), a fixed substrate (5), a metal reflection floor (6), and a microstrip power divider (7). The strongly coupled conformal dipole linear array (2) operates in a vertical polarization state and is composed of six strongly coupled dipole units (211-216), which are completely conformally printed on the upper surface of the wing carrier profile (1), wherein the upper layer has three dipole units (211, 212, 213), the lower layer has three dipole units (214, 215, 216), the edge dipole units (211, 216) are additionally extended, and the extended metal patches (202-203) are printed on the back plate of the wing carrier profile (1). The dipole units (213, 214) are directly connected without gaps, ensuring the continuity of the current on the strongly coupled conformal dipole linear array (2), thereby widening the antenna operating frequency band, and at the same time facilitating solving the feeding problem caused by the narrow space at the wing tip and the problem that the wing tip with large curvature is difficult to conform to the shape; the gradient microstrip feeding balun (3) is welded to the corresponding six strongly coupled dipole units (211-216) at the top, inserted into the slot of the fixed substrate (5) on the metal reflective floor (6) at the bottom, and welded to the microstrip power divider (7) integrated on the upper surface of the fixed substrate (5), so that all the dipole units of the upper and lower layers of the wing carrier contour participate in the radiation, so that the maximum gain direction of the strongly coupled conformal dipole linear array (2) is directed to the wing tip.

2. The ferrite-loaded large curvature wing conformal strongly coupled ultra-wideband one-dimensional phased array antenna according to claim 1 is further characterized in that: The fixed substrate (5) is composed of two upper and lower dielectric substrates (501, 502) bonded together to form a wedge shape with a specific angle; the metal reflection floor (6) is composed of a metal sheet (601) and a metal sheet (602) in a wedge shape and is printed on the lower surface of the fixed substrate (5) to achieve control of beam pointing.

3. The ferrite-loaded large curvature wing conformal strongly coupled ultra-wideband one-dimensional phased array antenna according to claim 1 is further characterized in that: The microstrip power divider (7) is specially designed for the wing carrier platform and is composed of two parts, presenting a three-dimensional layout. One part is a one-to-two power divider (701) printed on the back plate of the wing carrier profile (1), and the other part is a one-to-three power divider (702) integrated on the upper surface of the fixed substrate (5) and a one-to-three power divider (703) integrated on the lower surface of the fixed substrate (5), which together form a one-to-six feeding network with only one input port, thereby achieving high integration with the large curvature wing conformal antenna, reducing processing costs and reducing the size of the antenna. The line length of the power divider is specially designed, and each output port outputs a specific phase, thereby achieving the function of regulating the beam pointing of the strongly coupled conformal dipole linear array (2), so that the maximum radiation direction points to the wing tip.

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