Miniaturized ultra-wideband linear array based on novel artificial magnetic conductor loading
By placing new artificial magnetic conductors on both sides of the ultra-wideband linear array, the problem of difficulty in miniaturizing and high radiation efficiency in the existing technology is solved, and the bandwidth expansion and efficient radiation effects are achieved.
Patent Information
- Application Number
- CN202510426233.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-07
- Publication Date
- 2025-06-20
AI Technical Summary
Existing ultra-wideband linear arrays are difficult to achieve both miniaturization and high radiation efficiency. They usually expand bandwidth by increasing the array element size or loading high-loss materials, resulting in large array size or low radiation efficiency.
By placing new artificial magnetic conductors on both sides of the ultra-wideband linear array, the high impedance characteristics can be used to compensate the ideal magnetic conductor boundary conditions of the linear array, thereby expanding the low-frequency bandwidth.
The bandwidth expansion of the miniaturized ultra-wideband linear array has been achieved, and the array has the advantage of high radiation efficiency due to the lack of high loss materials.
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Figure CN120184581A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of phased array antennas, and particularly relates to a miniaturized ultra-wideband linear array based on a novel artificial magnetic conductor loading. Background Art
[0002] Ultra-wideband linear arrays are suitable for special carrier platforms such as wings. Since the available space on these carrier platforms is very narrow and long, only linear arrays can be installed. However, due to the serious loss of periodic boundaries in one dimension of the linear array, there is a strong truncation effect, and its bandwidth is often narrower than that of planar arrays.
[0003] For example, in the literature “R.W. Kindt and W.R. Pickles, “Ultrawideband all-metal flared-notch array radiator,” IEEE Trans. Antennas Propag., vol. 58, no. 11, pp. 3568–3575, Nov. 2010”, the bandwidth of the planar array in the literature can achieve more than 10 octaves, but when the planar array is modified into a linear array form, its bandwidth is reduced to 6.6 octaves.
[0004] Another example is the literature “H. Zhang, S. Yang, Y. Chen, J. Guo, and Z. Nie, “Wideband dual-polarized linear array of tightly coupled elements,” IEEE Trans. Antennas Propag., vol. 66, no. 1, pp. 476–480, Jan. 2018”. This literature has made some special designs for ultra-wideband linear arrays. By extending the dipole to reduce the edge effect, the proposed array has a relatively wide bandwidth, but its feeding structure is relatively complex and the array size is large, which cannot meet the miniaturization requirements.
[0005] Another example is the literature “S. Kim and S. Nam, “Bandwidth extension of dual-polarized 1-dtcda antenna using VMS,” IEEE Trans. Antennas Propag., vol. 67, no. 8, pp. 5305–5312, Aug. 2019”. The literature uses ferrite and metal grid loading to compensate the boundary conditions of the ultra-wideband linear array, expanding the bandwidth of the array. However, due to the large loss of ferrite, the radiation efficiency of the array is low.
[0006] It can be found that in existing solutions, the bandwidth of ultra-wideband linear arrays is generally expanded by increasing the element size or loading high-loss materials, resulting in a large array size or low radiation efficiency. To solve the above problems, a new design method for ultra-wideband linear arrays is proposed. By loading the designed novel artificial magnetic conductor on both sides of the ultra-wideband linear array, the bandwidth expansion of the miniaturized ultra-wideband linear array can be achieved. Compared with previous work, the proposed ultra-wideband one-dimensional linear array has the advantage of high radiation efficiency because no high-loss materials are used. Summary of the Invention
[0007] Aiming at the problem that it is difficult for ultra-wideband linear arrays to achieve miniaturization and high efficiency simultaneously, the present invention proposes a miniaturized ultra-wideband linear array based on the loading of a novel artificial magnetic conductor. By placing the artificial magnetic conductor on both sides of the tightly coupled elements and utilizing the high-impedance characteristics of the artificial magnetic conductor, the ideal magnetic conductor boundary condition compensation for the linear array is realized to expand the low-frequency bandwidth.
[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:
[0009] A miniaturized ultra-wideband linear array based on the loading of a novel artificial magnetic conductor, wherein the ultra-wideband linear array is composed of a one-dimensional periodic arrangement of a plurality of elements;
[0010] Characterized in that: the element includes an antenna structure and two artificial magnetic conductor loading structures;
[0011] The antenna structure includes a vertical dielectric substrate, a microstrip tapered balun feeding structure, a dipole radiator, and a horizontal metal floor;
[0012] The vertical dielectric substrate is vertically placed on the horizontal metal floor;
[0013] The microstrip tapered balun feeding structure includes a microstrip transmission line and a first transition metal sheet on the front of the vertical dielectric substrate, and a microstrip line ground and a second transition metal sheet on the back of the vertical dielectric substrate; the bottom end of the microstrip transmission line is connected to the inner conductor of the coaxial probe, and the bottom end of the microstrip line ground is connected to the coaxial metal floor, and their top ends are respectively connected to the dipole radiator through the transition metal sheets for feeding;
[0014] The dipole radiator includes a first dipole arm arranged on the front of the vertical dielectric substrate and a second dipole arm arranged on the back of the vertical dielectric substrate; wherein, the first dipole arm in one element is divided into a head part and a tail part, and the head part and the tail part respectively form a complete first dipole arm with the tail part and the head part of the adjacent unit; there is a partial overlap in the projection of the first dipole arm and the second dipole arm to form a capacitive coupling between adjacent elements;
[0015] The two artificial magnetic conductor loading structures are symmetrically placed on both sides of the antenna structure and are parallel to the antenna structure.
[0016] Preferably, the distance between the artificial magnetic conductor loading structure and the antenna structure is 0.3 to 0.6 high-frequency wavelengths, and the height of the artificial magnetic conductor loading structure is 0.4 to 0.7 high-frequency wavelengths.
[0017] Preferably, the artificial magnetic conductor loading structure is composed of an artificial magnetic conductor dielectric substrate and an artificial magnetic conductor metal patch array arranged on its surface; the artificial magnetic conductor metal patch array includes a plurality of periodically arranged patch units; in one array element, the longitudinal periodic number of the patch units is 4 to 7, and the transverse periodic number is 3 to 5.
[0018] Preferably, the patch unit is a rectangular patch, and a cross-shaped slit is arranged in the middle of the rectangular patch.
[0019] Preferably, the antenna structure further includes a grounding metal wire arranged on the back of the vertical dielectric substrate, and the grounding metal wire connects the second dipole arm to the metal ground.
[0020] Preferably, the bottom end of the microstrip tapered balun feeding structure is a 50Ω input port, and the top end is a high-impedance output port; the widths of the microstrip line metal ground and the microstrip transmission line both gradually decrease from bottom to top to achieve broadband impedance matching.
[0021] Preferably, the lower regions of the vertical dielectric substrates of two adjacent array elements are hollowed out, so that the vertical dielectric substrate in one array element forms a symmetric T-shaped shape for convenient installation.
[0022] Preferably, the dipole radiator adopts a bow-tie dipole.
[0023] Preferably, the transition metal sheet is a rectangular metal patch for realizing the transition from the high-impedance output port to the dipole radiator.
[0024] The working principle of the present invention is as follows:
[0025] For the dipole radiator, the overlapping of the ends of adjacent dipoles will form strong capacitive coupling, and due to the existence of the metal floor, the impedance of the dipole input port will show strong inductive reactance in the low-frequency band; the present invention realizes low-frequency impedance matching based on the principle of capacitance-inductance complementarity by adjusting the capacitive coupling at the ends of the dipoles and the inductive reactance brought by the metal floor to expand the array bandwidth.
[0026] For an ultra-wideband linear array based on the tight coupling principle, a bandwidth of several times or even more than ten times the octave can be achieved in an infinitely large planar array; however, in practical applications, the ultra-wideband linear array cannot be extended infinitely, so there is a truncation effect. Due to the influence of the truncation effect, the mutual coupling effect between array elements weakens, and the array bandwidth is sharply reduced. To weaken the influence of the truncation effect, the present invention equates the tight coupling array to a waveguide model, places artificial perfect magnetic conductors on both sides of the array, restores the missing boundary conditions, and simulates the situation of an infinitely large planar array. Therefore, the present invention can extend the bandwidth of the tight coupling linear array to 5 times the octave, greatly expanding the bandwidth of the ultra-wideband linear array. Description of the Drawings
[0027] Figure 1 Schematic diagram of the 1×4 array of the ultra-wideband linear array of the present invention;
[0028] Figure 2 Overall 3D schematic diagram of the unit of the ultra-wideband linear array of the present invention;
[0029] Figure 3 Cross-sectional view of the artificial magnetic conductor structure of the ultra-wideband linear array of the present invention;
[0030] Figure 4 Front side view of the antenna unit of the ultra-wideband linear array of the present invention;
[0031] Figure 5 Back side view of the antenna unit of the ultra-wideband linear array of the present invention;
[0032] Figure 6 Simulation curve graph of the standing wave ratio of the antenna array at 60° scanning in a specific embodiment of the present invention.
[0033] Description of the reference numerals in the drawings: 1. Artificial magnetic conductor loading structure, 11. Artificial magnetic conductor dielectric substrate, 12. Patch unit, 13. Cross slot; 2. Antenna structure, 21. Vertical dielectric substrate, 22. Microstrip tapered balun feeding structure, 221. Tapered microstrip transmission line, 222. Metal ground of the tapered microstrip line, 223. Transition metal sheet, 23. Dipole radiator, 231. First dipole arm head part, 232. First dipole arm tail part, 233. Second dipole arm, 24. Grounding wire, 3. Metal floor. Detailed Embodiment
[0034] The present invention will be further described below in conjunction with the drawings and embodiments.
[0035] This embodiment provides a miniaturized ultra-wideband linear array based on a novel artificial magnetic conductor loading, as Figure 1 shown, the ultra-wideband linear array is composed of a one-dimensional periodic arrangement of several array elements;
[0036] The array element, as Figures 2-5As shown, it includes an antenna structure and two artificial magnetic conductor loading structures.
[0037] The antenna structure includes a vertical dielectric substrate, a microstrip tapered balun feeding structure, a dipole radiator, and a horizontal metal floor.
[0038] The vertical dielectric substrate is vertically placed in the middle of the horizontal metal floor; the thickness of the horizontal metal floor is 1 mm.
[0039] The vertical dielectric substrate has a height of 76 mm, a width of 70 mm, a thickness of 1.014 mm, and a dielectric constant of 3.0; the lower half of the vertical dielectric substrate is hollowed out on both the left and right sides to form a mirror-symmetrical T shape, the hollowing height is 56 mm, and the remaining width is 46 mm.
[0040] The microstrip tapered balun feeding structure includes a tapered microstrip transmission line and a first rectangular transition metal sheet on the front of the vertical dielectric substrate, and a tapered microstrip line ground and a second rectangular transition metal sheet on the back of the vertical dielectric substrate. The bottom ends of the microstrip transmission line and the microstrip line ground are 50Ω input ports, which are respectively connected to the inner conductor of the coaxial probe and the metal floor, and the top ends are high-impedance output ports, and are connected to the dipole radiator through a rectangular transition metal sheet with a width of 3 mm and a height of 8 mm for feeding. The width of the microstrip line ground gradually changes from 10 mm to 0.16 mm, and the width of the microstrip transmission line gradually changes from 2.3 mm to 0.16 mm to achieve broadband impedance matching.
[0041] The dipole radiator adopts a bow-tie dipole, including a first dipole arm arranged on the front of the vertical dielectric substrate and a second dipole arm arranged on the back of the vertical dielectric substrate; the input port height of the dipole arm is 2 mm, and the tail end height is 20 mm. In one element, the first dipole arm is divided into a head part and a tail part, and the head part and the tail part respectively form a complete first dipole arm with the tail part and the head part of the adjacent unit; there is an overlapping part with a width of 30 mm between the projected tails of the first dipole arm and the second dipole arm to form capacitive coupling between adjacent elements. The antenna structure also includes a grounding metal wire with a width of 2 mm arranged on the back of the vertical dielectric substrate, and the grounding metal wire connects the second dipole arm to the metal ground.
[0042] The two artificial magnetic conductor loading structures are symmetrically placed on both sides of the antenna structure, 42 mm away from the antenna structure and parallel to the antenna structure.
[0043] Specifically, the artificial magnetic conductor loading structure is composed of an artificial magnetic conductor dielectric substrate and an artificial magnetic conductor metal patch array arranged on its surface.
[0044] Among them, the height of the artificial magnetic conductor dielectric substrate is 80 mm, the width is 70 mm, the thickness is 1.024 mm, and the relative dielectric constant of the dielectric is 2.2.
[0045] The artificial magnetic conductor metal patch array includes 4*5 patch units arranged in a periodic pattern; the length and width of each patch unit are both 13 mm, the lateral spacing between adjacent patch units is 4.5 mm, and the longitudinal spacing is 3 mm; a cross-shaped metal slit is provided at the center of the patch unit, with the length of the slit being 9 mm and the width being 3.2 mm.
[0046] Such as Figure 6 This is the standing wave ratio simulation curve graph of this embodiment. For the linear array without artificial magnetic conductor loading, its typical working bandwidth is about 0.8 - 2 GHz, and the frequency bandwidth multiplication ratio is less than 3:1. The simulation results show that the proposed ultra-wideband linear array based on the novel artificial magnetic conductor loading can achieve a bandwidth of 0.4 - 2 GHz, a scanning angle of ±60°, and the standing wave ratio within the working frequency band is below 3.5.
[0047] The present invention is not limited to the embodiments described above. The above description of the specific embodiments is intended to describe and illustrate the technical solutions of the present invention. The above specific embodiments are merely illustrative and not restrictive. Without departing from the spirit of the present invention and the scope protected by the claims, those of ordinary skill in the art can make many specific transformations in various forms under the inspiration of the present invention, and these all fall within the protection scope of the present invention.
Claims
1. A miniaturized ultra-wideband linear array based on a new type of artificial magnetic conductor loading, wherein the ultra-wideband linear array is composed of a plurality of array elements arranged in a one-dimensional periodic manner; Features: The array element comprises an antenna structure and two artificial magnetic conductor loading structures; The antenna structure includes a vertical dielectric substrate, a microstrip gradient balun feeding structure, a dipole radiator, and a horizontal metal floor; The vertical dielectric substrate is placed vertically on a horizontal metal floor; The microstrip gradient balun feeding structure comprises a microstrip transmission line and a first transition metal sheet located on the front side of a vertical dielectric substrate, and a microstrip line metal ground and a second transition metal sheet located on the back side of the vertical dielectric substrate; the bottom end of the microstrip transmission line is connected to the inner conductor of the coaxial probe, the bottom end of the microstrip line metal ground is connected to the coaxial metal floor, and the top ends of the two are respectively connected to the dipole radiator through the transition metal sheet for feeding; The dipole radiator comprises a first dipole arm arranged on the front side of a vertical dielectric substrate and a second dipole arm arranged on the back side of the vertical dielectric substrate; wherein the first dipole arm in an array element is divided into a head end portion and a tail end portion, and the head end portion and the tail end portion respectively form a complete first dipole arm with the tail end portion and the head end portion of an adjacent unit; the projections of the first dipole arm and the second dipole arm partially overlap to form capacitive coupling between adjacent array elements; The two artificial magnetic conductor loading structures are symmetrically placed on both sides of the antenna structure and are parallel to the antenna structure.
2. A miniaturized ultra-wideband linear array based on novel artificial magnetic conductor loading as claimed in claim 1, characterized in that: The distance between the artificial magnetic conductor loading structure and the antenna structure is 0.3 to 0.6 high-frequency wavelengths, and the height of the artificial magnetic conductor loading structure is 0.4 to 0.7 high-frequency wavelengths.
3. A miniaturized ultra-wideband linear array based on novel artificial magnetic conductor loading as claimed in claim 2, characterized in that: The artificial magnetic conductor loading structure is composed of an artificial magnetic conductor medium substrate and an artificial magnetic conductor metal patch array arranged on the surface thereof; the artificial magnetic conductor metal patch array includes a plurality of periodically arranged patch units; in one array element, the number of longitudinal periods of the patch unit is 4 to 7, and the number of transverse periods is 3 to 5.
4. A miniaturized ultra-wideband linear array based on novel artificial magnetic conductor loading as claimed in claim 3, characterized in that: The patch unit is a rectangular patch with a cross-shaped gap in the middle.
5. A miniaturized ultra-wideband linear array based on novel artificial magnetic conductor loading as claimed in any one of claims 1 to 4, characterized in that: The antenna structure also includes a grounding metal wire arranged on the back side of the vertical dielectric substrate, and the grounding metal wire connects the second dipole arm to the metal ground.
6. A miniaturized ultra-wideband linear array based on novel artificial magnetic conductor loading as claimed in any one of claim 5, characterized in that: The bottom of the microstrip gradient balun feeding structure is a 50Ω input port, and the top is a high-impedance output port; the width of the microstrip metal ground and the microstrip transmission line gradually decreases from bottom to top to achieve broadband impedance matching.
7. A miniaturized ultra-wideband linear array based on novel artificial magnetic conductor loading as claimed in any one of claim 6, characterized in that: The lower regions of the vertical dielectric substrates of two adjacent array elements are hollowed out, so that the vertical dielectric substrate in one array element forms a symmetrical T-shape.
8. A miniaturized ultra-wideband linear array based on novel artificial magnetic conductor loading as claimed in any one of claim 7, characterized in that: The dipole radiator is a bow tie dipole.
9. A miniaturized ultra-wideband linear array based on novel artificial magnetic conductor loading as claimed in any one of claim 8, characterized in that: The transition metal sheet is a rectangular metal patch used to achieve the transition from the high impedance output port to the dipole radiator.