Antenna unit based on a stepped super surface

Abstract

The application discloses an antenna unit based on a stepped metasurface, which comprises a first metal plate, a lower dielectric substrate, a second metal plate and an upper dielectric substrate which are sequentially stacked; a substrate integrated waveguide feed line is arranged between the first metal plate and the second metal plate; the metal plate is etched with a feed gap; the upper dielectric substrate is provided with a single-sided stepped metasurface structure or a double-sided stepped metasurface structure; the feed gap is excited by the substrate integrated waveguide feed line, and then the single-sided stepped metasurface structure or the double-sided stepped metasurface structure on the upper side is excited to generate linearly polarized radiation; the beam deflection and wide beam performance are realized while a relatively wide impedance bandwidth is ensured.

Description

Technical Field

[0001] This invention belongs to the field of millimeter-wave communication technology, specifically relating to antenna elements based on stepped metasurfaces. Background Technology

[0002] With the development of fifth-generation (5G) wireless communication systems, 5G network construction and terminal equipment have gradually taken shape and entered the commercial stage. Unlike the 5G era, the core of 6G network construction lies in satellite internet technology, aiming to build an integrated network and achieve truly seamless global coverage. In the 6G era, millimeter waves will be the preferred broadband transmission technology for inter-satellite links, user links, and feeder links. The path loss and limited scattering problems faced by radio waves in the millimeter wave band can be solved through phased array technology, achieving wide-range beam scanning in the azimuth and elevation planes. Utilizing the rich electromagnetic properties of metasurfaces, antennas can achieve high gain, wide bandwidth, miniaturization, low profile, and low mutual coupling, enabling broadband and high-efficiency directional radiation. For millimeter-wave phased array applications, research into compact metasurface antennas suitable for large phased arrays, combined with packaging technology, is of significant value and importance in promoting the development of millimeter-wave communication technology.

[0003] However, millimeter-wave phased array technology is not yet mature enough. Due to the severe gain attenuation caused by the coupling effect between array elements, millimeter-wave communication still faces the problems of narrow beam scanning range and severe performance degradation during wide-angle scanning. Summary of the Invention

[0004] The purpose of this invention is to provide an antenna element based on a stepped metasurface that achieves beam deflection and wide beam performance while ensuring a wide impedance bandwidth.

[0005] To achieve the above objectives, the first aspect of the present invention provides:

[0006] An antenna element based on a stepped metasurface includes a first metal plate, a lower dielectric substrate, a second metal plate, and an upper dielectric substrate stacked sequentially; a substrate-integrated waveguide feed line is disposed between the first metal plate and the second metal plate; the metal plate is etched with the feed gap;

[0007] The upper dielectric substrate is provided with a single-sided stepped metasurface structure or a double-sided stepped metasurface structure; the feeding gap is excited by the substrate integrated waveguide feed line, which in turn excites the upper single-sided stepped metasurface structure or double-sided stepped metasurface structure and generates linearly polarized radiation.

[0008] Preferably, the substrate integrated waveguide feed line includes multiple metal vias A; the metal vias A are embedded in the underlying dielectric substrate; one end of the metal via A is connected to the first metal plate, and the other end of the metal via A is connected to the second metal plate; the multiple metal vias A are arranged in a U-shape; the feeding gap is disposed in the U-shaped substrate integrated waveguide feed line.

[0009] Preferably, the upper dielectric substrate is divided into multiple dielectric sub-boards along the vertical direction; the upper dielectric substrate is provided with metal patches distributed in an M×N matrix; adjacent columns of metal patches are separated by dielectric sub-boards to form a single-sided stepped metasurface structure or a double-sided stepped metasurface structure.

[0010] Preferably, the height of each column of metal patches increases progressively from one side of the single-sided stepped metasurface structure to the other side.

[0011] Preferably, two adjacent columns of metal patches are separated by multiple dielectric sub-plates. The beam deflection angle of the unilateral stepped metasurface structure can be changed by adjusting the number of dielectric sub-plates between two adjacent columns of metal patches. The more dielectric sub-plates between two adjacent columns of metal patches, the larger the beam deflection angle of the unilateral stepped metasurface structure.

[0012] Preferably, the feeding gap is offset from the center of the substrate integrated waveguide feed line; and the farther the feeding gap is offset from the center of the substrate integrated waveguide feed line, the greater the beam deflection angle of the single-sided stepped metasurface structure.

[0013] Preferably, the height of each column of metal patches increases gradually from the sides of the double-sided stepped metasurface structure to the middle of the double-sided stepped metasurface structure, and the metal patches of the double-sided stepped metasurface structure are arranged symmetrically and periodically.

[0014] Preferably, the double-sided stepped metasurface structure has M / 4+1 steps, with the first and last steps consisting of 2×N metal patches, and each intermediate step consisting of 4×N metal patches; the 2×N metal patches in each intermediate step are connected to the metal patches in the adjacent upper step through metal vias B; the 2×N metal patches in each intermediate step are connected to the metal patches in the adjacent lower step through metal vias B; and the metal vias B are disposed within the dielectric sub-board.

[0015] Preferably, the power feeding gap corresponds to the center of the double-sided stepped metasurface structure.

[0016] Preferably, the lower dielectric substrate includes a multilayer dielectric sub-board, which is arranged horizontally; the dielectric constant of the dielectric sub-board is 5.9 and the thickness is 0.094 mm; the thickness of the first metal plate and the second metal plate is 0.008 mm.

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0018] In this invention, the upper dielectric substrate is provided with a single-sided stepped metasurface structure or a double-sided stepped metasurface structure; the feeding slot is excited by the substrate integrated waveguide feed line, which in turn excites the upper single-sided stepped metasurface structure or double-sided stepped metasurface structure and generates linearly polarized radiation; by adjusting the single-sided stepped metasurface structure or double-sided stepped metasurface structure, the radiation direction of each slot is deflected, thereby realizing the control of beam pointing.

[0019] In this invention, 2×N metal patches in each intermediate step are connected to the metal patches in the adjacent upper step through metal vias B; 2×N metal patches in each intermediate step are connected to the metal patches in the adjacent lower step through metal vias B; the metal vias B are disposed within the dielectric sub-board; by disposing of the metal vias B, vertical current is introduced, enhancing the horizontal radiation intensity and widening the beamwidth of the synthesized radiation pattern of the antenna element.

[0020] In this invention, a first metal plate, a lower dielectric substrate, a second metal plate, and an upper dielectric substrate are arranged sequentially, with a substrate-integrated waveguide feed line disposed between the first and second metal plates; the metal plates are etched with the feed gap; the upper dielectric substrate is provided with a single-sided stepped metasurface structure or a double-sided stepped metasurface structure; it has the characteristics of small size, low profile, simple structure, and flexible design, and can achieve wide beamwidth and beam control, which can improve the performance of wide-angle scanning of millimeter-wave phased arrays and thus enable mass production. Attached Figure Description

[0021] Figure 1 This is a three-dimensional schematic diagram of the antenna unit based on a stepped metasurface in Embodiment 1 of the present invention;

[0022] Figure 2 This is a side view of the antenna element based on a stepped metasurface in Embodiment 1 of the present invention;

[0023] Figure 3 This is a top view and a schematic diagram showing the dimensions of the beam deflection antenna based on a stepped metasurface in Embodiment 1 of the present invention.

[0024] Figure 4 This is a three-dimensional schematic diagram of the antenna unit based on a stepped metasurface in Embodiment 2 of the present invention;

[0025] Figure 5 This is a side view of the antenna element based on a stepped metasurface in Embodiment 2 of the present invention;

[0026] Figure 6This is a top view and a schematic diagram showing the dimensions of the antenna element based on the stepped metasurface in Embodiment 2 of the present invention;

[0027] Figure 7 This is a result diagram of the S-parameters of the antenna element based on the stepped metasurface in Embodiment 1 of the present invention;

[0028] Figure 8 This is the radiation pattern of the antenna element based on the stepped metasurface in Embodiment 1 of the present invention;

[0029] Figure 9 This is a result diagram of the S-parameters of the antenna element based on the stepped metasurface in Embodiment 2 of the present invention;

[0030] Figure 10 This is a graph showing the radiation gain of the antenna element based on the stepped metasurface in Embodiment 2 of the present invention.

[0031] Figure 11 This is the main polarization and cross-polarization pattern of the wide-beam antenna based on a stepped metasurface in Embodiment 2 of the present invention at a center frequency of 71 GHz;

[0032] Figure 12 This is a comparison diagram of the beamwidth of the wide-beam antenna based on the stepped metasurface and the microstrip patch antenna in Embodiment 2 of the present invention;

[0033] In the figure: 1 First metal plate, 2 Lower dielectric substrate, 3 Second metal plate, 4 Upper dielectric substrate, 5 Substrate integrated waveguide feed line, 6 Feed gap, 7 Metal patch, 8 Metal via B. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0035] It should be noted that in the description of this invention, the terms "front," "rear," "left," "right," "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "front," "rear," "left," "right," "upper," and "lower" used in the description of this invention refer to the directions shown in the accompanying drawings, while the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0036] Example 1

[0037] like Figures 1 to 2As shown, the antenna element based on a stepped metasurface includes a first metal plate, a lower dielectric substrate, a second metal plate, and an upper dielectric substrate stacked sequentially. A substrate integrated waveguide feed line is disposed between the first metal plate and the second metal plate. The substrate integrated waveguide feed line includes multiple metal vias A. The metal vias A are embedded in the lower dielectric substrate. One end of the metal via A is connected to the first metal plate, and the other end of the metal via A is connected to the second metal plate. The multiple metal vias A are arranged in a U-shape. The feed gap is disposed within the U-shaped substrate integrated waveguide feed line.

[0038] The metal plate is etched with the feeding slot; the feeding slot is offset from the center of the substrate integrated waveguide feed line; and the farther the feeding slot is from the center of the substrate integrated waveguide feed line, the greater the deflection angle of the emitted beam of the single-sided stepped metasurface structure; the feeding slot is one, and the shape of the feeding slot is not limited, and can be H-shaped, U-shaped, I-shaped, etc.

[0039] The upper dielectric substrate is divided into multiple dielectric sub-boards along the vertical direction; the upper dielectric substrate is provided with metal patches distributed in an M×N matrix; adjacent columns of metal patches are separated by at least one dielectric sub-board to form a single-sided stepped metasurface structure; the height of each column of metal patches increases stepwise from one side of the single-sided stepped metasurface structure to the other side.

[0040] In this embodiment, the double-sided stepped metasurface structure consists of 8×2 square metal patches, with a total of 3 steps. Each step is separated by a dielectric substrate. The first and last steps each have 2×2 metal patches, while the middle steps each have 4×2 metal patches. The metal patches are not limited to a square structure; they can also be parallelogram-shaped, trapezoidal, or ring-shaped structures.

[0041] The beam deflection angle of the unilateral stepped metasurface structure can be changed by adjusting the number of dielectric sub-plates between two adjacent columns of metal patches. The more dielectric sub-plates between two adjacent columns of metal patches, the greater the tilt angle of the center line connecting the metal patches in each row, and the greater the beam deflection angle of the unilateral stepped metasurface structure.

[0042] The feed gap is excited by the substrate integrated waveguide feed line, which in turn excites the single-sided stepped metasurface structure above and generates linearly polarized radiation.

[0043] like Figure 3 As shown, the specific dimensions of each part are as follows: the dielectric constant of the dielectric sub-board is 5.9, the dielectric sub-board is Ferro A6ME, the thickness of a single-layer dielectric sub-board is 0.094mm, the upper dielectric substrate contains 4 layers of dielectric sub-boards, and the lower dielectric substrate contains 3 layers of dielectric sub-boards; the thickness of the first metal plate and the second metal plate is 0.008mm, and the side length W of the first metal plate and the second metal plate is 2.6mm.

[0044] The square metal patch of the single-sided stepped metasurface structure has a width w1 of 0.4 mm and lengths l1, l2, and l3 of 0.4 mm, 0.3 mm, and 0.3 mm, respectively; the edge spacing g between two adjacent columns of metal patches in the Y-axis direction is 0.1 mm.

[0045] The feed gap has a length sl of 0.85 mm and a width sw of 0.1 mm. The distance bias of the feed gap from the center of the single-sided stepped metasurface structure is 0.5 mm. The width siw_w of the substrate integrated waveguide is 1.2 mm, the diameter d of the metal via A is 0.1 mm, and the center-to-center spacing p between adjacent metal vias A is 0.3 mm. Here, λ is the free-space wavelength corresponding to the center frequency, and λg0 is the effective wavelength of the medium corresponding to the center frequency. In this embodiment, λ is taken as 11.11 mm, and λg0 is taken as 4.574 mm.

[0046] By adjusting the arrangement of the single-sided stepped metasurface structure, the phase distribution of the interlayer metasurfaces in the antenna can be altered. The equiphase radiation surface and phase distribution are consistent, thereby changing the distribution of the antenna aperture field and causing a deflection of the radiation direction of each slot. For example... Figure 7 As shown, the beam deflection antenna based on a stepped metasurface operates in the 66-76 GHz frequency band. The antenna exhibits good matching at the center frequency and a return loss of less than -15 dB. Furthermore, the antenna's radiation direction... Figure 8 As can be seen, compared with the planar patch antenna, the beam deflection antenna achieves a maximum beam offset of 34° in the specified direction.

[0047] Example 2

[0048] like Figure 4 and Figure 5 As shown, the antenna unit based on the stepped metasurface includes a first metal plate, a lower dielectric substrate, a second metal plate, and an upper dielectric substrate stacked sequentially; a substrate integrated waveguide feed line is disposed between the first metal plate and the second metal plate;

[0049] The substrate integrated waveguide feed line includes multiple metal vias A; the metal vias A are embedded in the underlying dielectric substrate; one end of the metal via A is connected to the first metal plate, and the other end of the metal via A is connected to the second metal plate; the multiple metal vias A are arranged in a U-shape; the feeding gap is disposed in the U-shaped substrate integrated waveguide feed line.

[0050] The upper dielectric substrate is divided into multiple dielectric sub-boards along the vertical direction; the upper dielectric substrate is provided with metal patches distributed in an M×N matrix, and two adjacent columns of metal patches are separated by at least one dielectric sub-board to form a double-sided stepped metasurface structure; the height of each column of metal patches increases gradually from the sides of the double-sided stepped metasurface structure to the middle of the double-sided stepped metasurface structure, and the metal patches of the double-sided stepped metasurface structure are arranged symmetrically and periodically.

[0051] The beam deflection angle of the single-sided stepped metasurface structure can be changed by adjusting the number of dielectric sub-plates between two adjacent columns of metal patches. The more dielectric sub-plates between two adjacent columns of metal patches, the greater the beam width of the double-sided stepped metasurface structure.

[0052] The double-sided stepped metasurface structure has M / 4+1 steps. The first and last steps each have 2×N metal patches, and each intermediate step has 4×N metal patches. The 2×N metal patches in each intermediate step are connected to the metal patches in the adjacent upper step via metal vias B. Similarly, the 2×N metal patches in each intermediate step are connected to the metal patches in the adjacent lower step via metal vias B. The metal vias B are located within the dielectric sub-board. A vertical current is introduced into the metal vias B to generate radiation in the end-fire direction. The radiation pattern generated by the stepped metasurface is superimposed on the radiation pattern generated by the two, improving the gain at low elevation angles and effectively widening the antenna beamwidth.

[0053] In this embodiment, the double-sided stepped metasurface structure is composed of 8×2 square metal patches, with a total of 3 steps. Each step is separated by a dielectric substrate. The first and last steps each have 2×2 metal patches, and each of the middle steps has 4×2 metal patches. The metal patches are not limited to square structures, but can also be parallelogram, trapezoid, ring, or other structures.

[0054] The metal plate is etched with the feeding slot; the feeding slot corresponds to the center of the double-sided stepped metasurface structure; the feeding slot is a single piece, and its shape is not limited, and can be H-shaped, U-shaped, I-shaped, etc.; the feeding slot is excited by the substrate integrated waveguide feed line, which in turn excites the upper double-sided stepped metasurface structure and generates linear polarized radiation.

[0055] like Figure 6 As shown, the specific dimensions of each part are as follows: the dielectric constant of the dielectric sub-board is 5.9, the thickness of a single-layer dielectric sub-board is 0.094mm, the upper dielectric substrate has 4 layers, and the lower dielectric substrate has 3 layers; the thickness of the first metal plate and the second metal plate is 0.008mm, and the side length W of the first metal plate and the second metal plate is 2.6mm.

[0056] The square metal patch with a double-sided stepped metasurface structure has a width w1 of 0.4 mm and lengths l1, l2, and l3 of 0.25 mm, 0.15 mm, and 0.2 mm, respectively. The edge spacing g1 between two adjacent metal patches in the X-axis direction is 0.1 mm, and the edge spacing g2 in the Y-axis direction is 0.1 mm. The diameter d of the metal via B connecting the metal patches is 0.1 mm.

[0057] The feed gap has a length sl of 0.85 mm and a width sw of 0.1 mm; the substrate integrated waveguide has a width siw_w of 1.2 mm, the metal via A has a diameter d of 0.1 mm, and the center-to-center distance p between adjacent metal vias A is 0.3 mm.

[0058] like Figure 9 , Figure 10 As shown, it exhibits good matching at the center frequency and a wide impedance bandwidth of 24%. Within the operating frequency band of 66GHz-76GHz, the return loss is less than -15dB, and the in-band gain is 3.5dBi-5.34dB. Compared to planar metasurface antenna elements, the stepped metasurface antenna element achieves an E-plane half-power beamwidth of 125°-149° within the operating frequency band. Figure 11 As shown, the cross-polarization of the wide-beam antenna is less than -30dB.

[0059] Combination Figure 12 Table 1 shows a comparison of the radiation patterns of an antenna based on a double-sided stepped metasurface structure and a microstrip patch. The solid line represents the wide-beam antenna based on the stepped metasurface, while the dashed line represents the microstrip patch, with the microstrip patch antenna having a beamwidth of approximately 85°. The performance comparison at the three frequency points in the figure reveals that the beamwidth effect is more significant at high frequencies compared to low frequencies. The beamwidth remains greater than 125° throughout the entire operating frequency band, reaching 149° at high frequencies. Correspondingly, the antenna gain versus frequency curve shows that as the antenna frequency increases, the beamwidth widens while the gain decreases.

[0060] Table 1 Beamwidth Comparison Table

[0061]

[0062] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An antenna element based on a stepped metasurface, characterized in that, The device includes a first metal plate, a lower dielectric substrate, a second metal plate, and an upper dielectric substrate stacked sequentially; a substrate-integrated waveguide feed line is disposed between the first metal plate and the second metal plate; and the metal plates are etched with feed gaps. The upper dielectric substrate is provided with a single-sided stepped metasurface structure or a double-sided stepped metasurface structure; the feeding gap is excited by the substrate integrated waveguide feed line, which in turn excites the upper single-sided stepped metasurface structure or double-sided stepped metasurface structure and generates linearly polarized radiation. The substrate-integrated waveguide feed line includes multiple metal vias A; the metal vias A are embedded in the underlying dielectric substrate. One end of the metal via A is connected to the first metal plate, and the other end of the metal via A is connected to the second metal plate; Multiple metal vias A are arranged in a U-shape; the feed gap is disposed within the U-shaped substrate integrated waveguide feed line; The upper dielectric substrate is divided into multiple dielectric sub-boards along the vertical direction; the upper dielectric substrate is provided with metal patches distributed in an M×N matrix. Adjacent rows of metal patches are separated by a dielectric sub-plate to form a single-sided stepped metasurface structure or a double-sided stepped metasurface structure.

2. The antenna element based on a stepped metasurface according to claim 1, characterized in that, The height of each column of metal patches increases progressively from one side of the stepped metasurface structure to the other.

3. The antenna element based on a stepped metasurface according to claim 2, characterized in that, The two adjacent rows of metal patches are separated by multiple dielectric sub-plates. The beam deflection angle of the unilateral stepped metasurface structure can be changed by adjusting the number of dielectric sub-plates between the two adjacent rows of metal patches. The more dielectric sub-plates between the two adjacent rows of metal patches, the larger the beam deflection angle of the unilateral stepped metasurface structure.

4. The antenna element based on a stepped metasurface according to claim 2 or claim 3, characterized in that, The feeding gap is offset from the center of the substrate integrated waveguide feed line; and the farther the feeding gap is from the center of the substrate integrated waveguide feed line, the greater the beam deflection angle of the single-sided stepped metasurface structure.

5. The antenna element based on a stepped metasurface according to claim 1, characterized in that, The height of each column of metal patches increases gradually from the sides of the double-stepped metasurface structure to the middle of the double-stepped metasurface structure, and the metal patches of the double-stepped metasurface structure are arranged symmetrically and periodically.

6. The antenna element based on a stepped metasurface according to claim 5, characterized in that, The double-sided stepped metasurface structure has M / 4+1 steps. The first and last steps each have 2×N metal patches, and each intermediate step has 4×N metal patches. The 2×N metal patches in each intermediate step are connected to the metal patches in the adjacent upper step through metal vias B. The 2×N metal patches in each intermediate step are also connected to the metal patches in the adjacent lower step through metal vias B. The metal vias B are located within the dielectric sub-board.

7. The antenna element based on a stepped metasurface according to claim 6, characterized in that, The power supply gap corresponds to the center of the double-sided stepped metasurface structure.

8. The antenna element based on a stepped metasurface according to claim 1, characterized in that, The lower dielectric substrate includes a multilayer dielectric sub-board, which is arranged horizontally; the dielectric constant of the dielectric sub-board is 5.9 and the thickness is 0.094 mm; the thickness of the first metal plate and the second metal plate is 0.008 mm.

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