Log-periodic antenna and ultra-wideband dual-polarized low-profile conformal array antenna

Abstract

The invention discloses a log-periodic antenna and an ultra-wide-band dual-polarization low-profile conformal array antenna, and belongs to the technical field of design and manufacturing of ultra-wide-band antennas. The array element is formed by compounding and nesting two types of antennas including a miniaturized log-periodic antenna and a Vivaldi antenna, and the structure is multiplexed. According to the provided miniaturized log-periodic antenna, the broadband miniaturized conformal design is realized through composite loading methods such as array top loading, partial array bending, partial array loading dielectric blocks and the like. On the basis, the invention provides a design method for forming the dual-polarized antenna by nesting a Vivaldi antenna and a log-periodic antenna. A Vivaldi antenna is subjected to left and right block design, a radiation slot and an excitation slot are formed through splicing, and an assembly line of a log-periodic antenna is deployed on a left sector plate and a right sector plate of the Vivaldi antenna. According to the dual-polarization array forming mode, large-curvature conformality of the pitching surface is considered, and pitching surface wide-beam coverage and azimuth surface wide-angle scanning application can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of design and manufacturing of ultra-wideband antennas, and in particular to an ultra-wideband dual-polarization low-profile conformal array antenna. Background Art

[0002] On airborne conformal platforms, antenna installation dimensions are limited, and installation locations are often irregularly shaped. Antenna integration also requires considerations of radar cross section (RCS) and aerodynamics, requiring the minimum number of antennas and the lowest possible profile. Consequently, there is a strong demand for broadband, low-profile conformal array antennas.

[0003] According to literature research, current ultra-wideband conformal phased array antennas primarily take the form of tightly coupled dipole antennas (TCDA / PUMA) or ultra-wideband end-fire arrays, with mounting platforms typically flat or relatively regular curved. Furthermore, breakthroughs are needed in the dual-polarization design of low-profile end-fire arrays. Polarization diversity and frequency diversity can significantly increase communication capacity. Zhang Shaolin et al. proposed a dual-polarization log-periodic antenna in "Dual-Polarized Log-Periodic Antenna, Dual-Element Structure Antenna, and Antenna Array" (invention patent, application number: 201911119825.4). The antenna consists of four clustered wires with multiple antenna elements arranged alternately and evenly spaced in parallel. This composite structure achieves vertical / horizontal dual polarization, minimizing signal polarization loss and achieving good dual-polarization gain and radiation symmetry. However, the additional feed structure consumes considerable space, and the antenna has a relatively high profile. Miao Jungang et al. proposed a dual-polarized Vivaldi array antenna in "A Dual-Polarized Vivaldi Array Antenna and Assembly Method" (invention patent, application number: 202410454347.7). The antenna's horizontal and vertical sub-arrays are integrally formed, resulting in a relatively simple structure and stable and reliable performance. However, the bandwidth of a Vivaldi antenna is proportional to its vertical profile height. Therefore, the profile height would be too high to meet broadband requirements. Furthermore, the uniform width of the front and rear ends of the Vivaldi antenna also prevents conformal performance for large curvatures.

[0004] In terms of miniaturization of log-periodic antennas, researchers have tried different ways to reduce the size of the antenna. For example, loading different shapes on the dipole oscillator can effectively reduce the length of the oscillator. In "A New Ultra-Wideband High-Gain Miniaturized Log-Periodic Antenna" (invention patent, application number: 202010751679.3), Wang Zhijuan et al. proposed that by loading a top-hat structure on the dipole oscillator and adding inductive loads on some oscillators, the oscillator length can be effectively reduced, shortening the lateral size of the log-periodic antenna to 0.25. , while taking into account ultra-wideband and high gain characteristics. However, this antenna miniaturization method still has room for improvement in reducing the antenna's lateral size, because when the number of oscillators on the log-periodic antenna increases, the radiating arms of the second half of the oscillators are still too long. Summary of the Invention

[0005] The purpose of the present invention is to provide a miniaturized log-periodic antenna design scheme to address the defects and shortcomings of the existing technology, and to compositely nest this miniaturized log-periodic antenna with the Vivaldi antenna to form a new broadband dual-polarization array antenna that takes into account both wide beam coverage in the elevation plane and wide angle scanning applications in the azimuth plane.

[0006] The present invention is achieved through the following technical solutions: A miniaturized logarithmic periodic antenna comprises a dipole element, a collective line and a dielectric matching block; There are two set lines, which are arranged in parallel; there are N pairs of dipole oscillators, where N ≥ 1; the N pairs of dipole oscillators are divided into two groups, which are respectively connected to the two set lines; the dipole oscillators on the same set line are staggered from top to bottom; the dipole oscillators at the same height are respectively connected to the two set lines; Furthermore, a dielectric strip is provided between the two set lines.

[0007] Furthermore, each dipole oscillator is loaded with a top-hat structure.

[0008] Furthermore, the top-hat structure is a U-shaped branch, the opening of which is directly facing the radiation arm of the dipole oscillator it faces; and the radiation arm is connected inside the U-shaped branch to form an E shape.

[0009] Furthermore, the radiation arm of the low-frequency dipole oscillator is in the form of a meander curve.

[0010] Furthermore, a bending structure is provided at the end of the top-hat structure of the low-frequency dipole oscillator; and a dielectric matching block is loaded in the area surrounded by the radiation arm, the top-hat structure and the bending structure of the low-frequency dipole oscillator.

[0011] An ultra-wideband dual-polarization low-profile conformal array antenna includes a Vivaldi antenna and at least two miniaturized log-periodic antennas; the log-periodic antennas are parallel to each other and arranged in a straight line; The Vivaldi antenna includes a left fan plate and a right fan plate located in the same vertical plane; a radiation slot is provided between the left fan plate and the right fan plate, and the width of the radiation slot gradually decreases from top to bottom; A matching groove is provided at the bottom of the left fan plate, and the matching groove is rectangular; the radiation groove is connected to the matching groove through the excitation groove; The Vivaldi antenna is located between two adjacent log-periodic antennas, wherein the left fan plate and the right fan plate are respectively connected to the collective lines on the corresponding sides.

[0012] Furthermore, it also includes a base plate and a feeding structure; the Vivaldi antenna and the log-periodic antenna are both mounted on the upper surface of the base plate; the vertical plane where the Vivaldi antenna is located and the vertical plane where the log-periodic antenna is located are perpendicular to each other, and the Vivaldi antenna and the log-periodic antenna are both perpendicular to the base plate; The feeding structure includes a feeding coaxial cable and a feeding coaxial probe; the feeding coaxial cable passes through one of the collective lines, and the inner conductor is connected to the other collective line; the feeding coaxial probe is connected to the bottom of the Vivaldi antenna.

[0013] Furthermore, the excitation slot is divided into two sections, a first excitation slot and a second excitation slot; one end of the first excitation slot is connected to the radiation slot and extends vertically; the second excitation slot is a horizontal section, one end of which is connected to the bottom of the matching slot and the other end is connected to the first excitation slot.

[0014] Furthermore, the head end log-periodic antenna and the tail end log-periodic antenna of the linear array are respectively provided with a right fan plate and a left fan plate; The right fan plate is connected to the outer collective line of the head end log-periodic antenna; the left fan plate is connected to the tail end log-periodic antenna.

[0015] Compared with the prior art, the present invention has the following beneficial effects: First, a miniaturized log-periodic antenna is proposed. This antenna achieves a broadband, miniaturized, conformal design through a combination of three methods: a top-hat top-loading method, partial oscillator bending, and partial oscillator loading with dielectric blocks. Secondly, a design method is proposed in which a Vivaldi antenna and a log-periodic antenna are nested to form a dual-polarized antenna. The Vivaldi antenna is divided into left and right blocks, which are then spliced ​​together to form radiation slots and excitation slots. The log-periodic antenna's collection lines are then deployed on the left and right panels of the Vivaldi antenna through splicing. This dual-polarized array arrangement takes into account the large curvature conformality of the elevation plane, enabling both wide-beam coverage in the elevation plane and wide-angle scanning in the azimuth plane. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the three-dimensional structure of an ultra-wideband dual-polarization low-profile conformal array antenna of the present invention; Figure 2 It is a schematic diagram of the three-dimensional structure of an ultra-wideband dual-polarization low-profile conformal antenna unit of the present invention; Figure 3 It is a schematic diagram of the three-dimensional structure of a miniaturized log-periodic antenna of the present invention; Figure 4This is a schematic diagram of the distribution of dipole elements on a miniaturized log-periodic antenna of the present invention; Figure 5 This is a schematic structural diagram of the collective line portion of a miniaturized log-periodic antenna of the present invention; Figure 6 It is a schematic diagram of the structure and feeding interface of a Vivaldi antenna of the present invention. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0018] An ultra-wideband dual-polarization low-profile conformal array antenna comprises a high-curvature radome 1, an ultra-wideband dual-polarization low-profile conformal antenna 2, a feed structure 3, and a base plate 4. The high-curvature radome 1 has a high-curvature, shaped surface that conforms to the contours of the conformal platform. The ultra-wideband dual-polarization low-profile conformal antenna 2 consists of multiple miniaturized log-periodic antennas 21 and multiple Vivaldi antennas 22. The feed structure 3 comprises a feed coaxial cable and a feed coaxial probe 32.

[0019] The miniaturized log-periodic antenna 21 includes a top-hat loaded dipole element 211, a collection line 212, and a dielectric matching block 213. Dielectric strips 2121 are filled between the collection lines 212 to prevent short circuits caused by structural deformation.

[0020] The miniaturized log-periodic antenna 21 has N pairs of top-hat loaded dipole elements 211, distributed symmetrically along a collection line 212 on both sides. To further reduce the antenna's cross-sectional width, a meandering design is employed for the radiating arms of some low-frequency dipole elements 211, and a folded and extended design is employed for top-hat loading.

[0021] The end of the radiating arm of the dipole element 211 is connected to the collective line 212. The dielectric matching block 213 is located inside the area surrounded by a portion of the low-frequency dipole element 211 and plays a further matching role for the folded element.

[0022] The Vivaldi antenna 22 consists of a left fan plate 221, a right fan plate 222, a radiation slot 223, a first excitation slot 224, a second excitation slot 225, and a matching slot 226. The excitation slot 225 and the matching slot 226 are etched on the left fan plate 221. When the left fan plate 221 and the right fan plate 222 are spliced, the structural design ensures that the first excitation slot 224 and the radiation slot 223 are formed.

[0023] One end of the radiation slot 223 is connected to the first excitation slot 224 and the other end is open to the free space. The radiation slot 223, the first excitation slot 224, the second excitation slot 225 and the matching slot 226 are connected.

[0024] The two antenna units, the Vivaldi antenna 22 and the miniaturized log-periodic antenna 21 , have a flat structure and are electrically connected to each other.

[0025] The Vivaldi antenna 22 and the miniaturized log-periodic antenna 21 are arranged vertically. The miniaturized log-periodic antenna 21 is deployed on the left side of the left fan plate 221 and on the right side of the right fan plate 222. A pair of integrated lines 212 of the miniaturized log-periodic antenna are distributed on the left and right fan plates 221, 222 of the Vivaldi antenna.

[0026] When multiple elements of the ultra-wideband dual-polarization low-profile conformal antenna 2 are arrayed, a one-dimensional array is formed by sequentially splicing the left fan plate 221 and the right fan plate 222. Another dimensional array can be formed along the direction in which the logarithmic periodic array extends.

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments: The ultra-wideband dual-polarization low-profile conformal array antenna provided in this embodiment includes 16 array elements, and its structure is as follows: Figures 1 to 6 As shown, it includes, from top to bottom, a large curvature antenna cover 1, an ultra-wideband dual-polarization low-profile conformal antenna 2, a feeding structure 3 and a base plate 4.

[0028] like Figure 1 As shown, the curved surface of the high-curvature radome 1 is a highly shaped, contoured surface that adapts to the contours of the conformal platform. The ultra-wideband, dual-polarization, low-profile conformal array antenna is an end-fire array consisting of 16 vertically polarized elements and 16 horizontally polarized elements. The array antenna structure is based on a base plate, with the 16 antenna elements and the high-curvature radome 1 secured to the base plate 4 via screws.

[0029] like Figure 2 As shown, the ultra-wideband dual-polarization low-profile conformal antenna 2 consists of a miniaturized log-periodic antenna 21 and a Vivaldi antenna 22. The miniaturized log-periodic antenna 21 is fixed to the Vivaldi antenna 22 by screws. In the elevation direction, angular coverage is achieved through beam coverage. To achieve a ±60° scanning range in the azimuth plane, the array element spacing in the azimuth plane is selected to be 0.53λ. H .

[0030] like Figure 3 As shown, the miniaturized log-periodic antenna 21 includes a top-hat loaded dipole element 211, a collection line 212, and a dielectric matching block 213. The dielectric matching block 213 is partially wrapped by the low-frequency dipole element and further matches the folded dipole element.

[0031] like Figure 4 As shown, there are a total of N pairs of top-hat loaded dipole elements 211 on the miniaturized log-periodic antenna 21, which are symmetrically distributed on both sides of the collection line 212 in opposite directions. Here, a design of 15 pairs of elements is taken as an example. Starting from the top, the elements are numbered in order from short to long as follows: No. 1: 2111, No. 2: 2112, No. 3: 2113, No. 4: 2114, No. 5: 2115, No. 6: 2116, No. 7: 2117, No. 8: 2118, No. 9: 2119, No. 10: 21110, No. 11: 21111, No. 12: 21112, No. 13: 21113, No. 14: 21114 and No. 15: 21115. The heights from the vibrator to the plane where the collection line is located are 11.02mm, 12.73mm, 14.67mm, 16.88mm, 19.38mm, 22.24mm, 25.47mm, 29.15mm, 33.33mm, 38.08mm, 43.48mm, 49.61mm, 56.85mm, 64.5mm and 73.5mm from No. 1 to 15.

[0032] like Figure 4 As shown, in order to further reduce the width of the antenna profile, we adopt a meandering design for the radiating arms of the dipole elements 13-15, and a folded and extended design for the top-hat loading. The lateral size of the miniaturized log-periodic antenna 21 can be shortened to 103mm, approximately 0.12 (The lowest frequency corresponds to the wavelength).

[0033] like Figure 5 As shown, dielectric strips 2121 are filled between the cluster lines 212 to prevent structural deformation and short circuits. The radiating arms of all dipole elements 211 are rectangular, with one end connected to the cluster line 212. The cluster lines form a pair, each rectangular, with one side perforated with a feed coaxial cable 31 passing through it, and the inner conductor connected to the other side. The maximum radiation direction of the miniaturized log-periodic antenna 21 is from the longest element toward the shortest element.

[0034] like Figure 6 As shown, the Vivaldi antenna 22 consists of a left fan plate 221, a right fan plate 222, a radiation slot 223, a first excitation slot 224, a second excitation slot 225, and a matching slot 226. The second excitation slot 225 and the matching slot 226 are etched on the left fan plate. When the left fan plate 221 and the right fan plate 222 are spliced, the structural design ensures that the first excitation slot 224 and the radiation slot 223 are formed. One end of the radiation slot 223 is connected to the first excitation slot 224, and the other end is open to free space. The radiation slot 223, the first excitation slot 224, the second excitation slot 225, and the matching slot 226 are connected.

[0035] like Figure 6 As shown, the feeding coaxial probe 32 is connected to the tail end of the Vivaldi antenna 22 to feed the antenna input. The signal propagates forward from the tail end, gradually expands and radiates along the exponential feeding slot.

[0036] like Figure 6 and Figure 1 As shown, when multiple elements of the ultra-wideband dual-polarization low-profile conformal antenna 2 are arrayed, a one-dimensional array is formed by sequentially splicing the left fan plate 221 and the right fan plate 222. Another dimensional array can also be formed along the direction in which the logarithmic periodic array extends.

[0037] The characteristics of the ultra-wideband dual-polarization low-profile conformal array antenna described in the present invention were simulated by full-wave simulation using the electromagnetic simulation software Ansys Electronics Desktop. When the antenna operates at a frequency of 0.35 GHz to 0.5 GHz, the VSWR is ≤ 6; when operating at a frequency of 0.5 GHz to 2 GHz, the VSWR is ≤ 2.5, and the conformal array antenna has a scanning level drop of less than 6 dB within the range of ±60°.

[0038] It should be noted that the above description is only an example of a preferred application of the present invention and is not intended to limit the scope of protection of the present invention. Any technical solution that adopts equivalent replacement or equivalent transformation is within the scope of protection of the present invention.

Claims

1. A miniaturized log-periodic antenna, characterized in that: It includes a dipole oscillator (211), a collection line (212) and a dielectric matching block (213); Two collection lines (212) are provided, and the two collection lines (212) are arranged in parallel; a total of N pairs of dipole oscillators (211) are provided, wherein N≥1; the N pairs of dipole oscillators (211) are divided into two groups, and are respectively connected to the two collection lines; the dipole oscillators (211) on the same collection line are staggered from top to bottom; and the dipole oscillators (211) at the same height are respectively connected to the two collection lines.

2. A miniaturized log-periodic antenna according to claim 1, characterized in that: There is a dielectric strip (2121) between the two collection lines (212).

3. The miniaturized log-periodic antenna according to claim 1, wherein: Each dipole oscillator (211) is loaded with a top-hat structure.

4. The miniaturized log-periodic antenna according to claim 3, wherein: The top-hat structure is a U-shaped branch, wherein the opening of the U-shaped branch faces the radiation arm of the dipole oscillator (211) it faces; the radiation arm is connected inside the U-shaped branch to form an E shape.

5. The miniaturized log-periodic antenna according to claim 3, wherein: The radiation arm of the low-frequency dipole oscillator (211) is in the form of a meander curve.

6. The miniaturized log-periodic antenna according to claim 4, wherein: A bending structure is provided at the end of the top-hat structure of the low-frequency dipole oscillator (211); and a dielectric matching block (213) is loaded in an area surrounded by the radiation arm, the top-hat structure and the bending structure of the low-frequency dipole oscillator (211).

7. An ultra-wideband dual-polarization low-profile conformal array antenna, characterized in that: The invention comprises a Vivaldi antenna (22) and at least two miniaturized log-periodic antennas (21) according to any one of claims 3 to 5; the log-periodic antennas (21) are parallel to each other and arranged in a straight line; The Vivaldi antenna (22) comprises a left fan plate (221) and a right fan plate (222) located in the same vertical plane; a radiation slot (223) is provided between the left fan plate (221) and the right fan plate (222), and the width of the radiation slot (223) gradually decreases from top to bottom; A matching slot (226) is provided at the bottom of the left fan plate (221), and the matching slot (226) is rectangular; the radiation slot (223) is connected to the matching slot (226) via the excitation slot; The Vivaldi antenna (22) is located between two adjacent log-periodic antennas (21), wherein the left fan plate (221) and the right fan plate (222) are respectively connected to the collective line (212) on the corresponding side.

8. The ultra-wideband dual-polarization low-profile conformal array antenna according to claim 7, characterized in that: It also includes a base plate (4) and a feeding structure (3); the Vivaldi antenna (22) and the log-periodic antenna (21) are both mounted on the upper surface of the base plate (4); The vertical plane where the Vivaldi antenna (22) is located and the vertical plane where the log-periodic antenna (21) is located are perpendicular to each other, and both the Vivaldi antenna (22) and the log-periodic antenna (21) are perpendicular to the bottom plate (4); The feeding structure (3) includes a feeding coaxial cable (31) and a feeding coaxial probe (32); the feeding coaxial cable (31) passes through the inside of one of the collective lines (212), and the inner conductor is connected to the other collective line (212); the feeding coaxial probe (32) is connected to the bottom of the Vivaldi antenna (22).

9. The ultra-wideband dual-polarization low-profile conformal array antenna according to claim 7, characterized in that: The excitation slot is divided into two sections: a first excitation slot (224) and a second excitation slot (225); one end of the first excitation slot (224) is connected to the radiation slot (223) and extends vertically; the second excitation slot (225) is a horizontal section, one end of which is connected to the bottom of the matching slot (226) and the other end of which is connected to the first excitation slot (224); The bottoms of the left fan plate (221) and the right fan plate (222) are connected; the second excitation slot (225) and the matching slot (226) are located above the connection portion.

10. The ultra-wideband dual-polarization low-profile conformal array antenna according to claim 7, characterized in that: The logarithmic periodic antenna (21) at the head end and the logarithmic periodic antenna (21) at the tail end of the linear array are further provided with a right fan plate (222) and a left fan plate (221), respectively. The right fan plate (222) is connected to the outer collective line (212) of the head end logarithmic periodic antenna (21); and the left fan plate (221) is connected to the tail end logarithmic periodic antenna (21).

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