A millimeter wave two-dimensional scanning phased array antenna based on stacked metasurface units

Abstract

This invention discloses a millimeter-wave two-dimensional scanning phased array antenna based on stacked metasurface units, comprising a first metasurface structure and a second metasurface structure disposed above and below a first dielectric substrate; the first and second metasurface structures constitute stacked metasurface units; a plurality of stacked metasurface units are distributed in a rectangular array, and decoupling grounding branches are disposed between adjacent stacked metasurface units; a metal ground plane is disposed between a second and a third dielectric substrate, and a plurality of coupling slots are disposed on the metal ground plane; a plurality of feeding networks are disposed below the third dielectric substrate; the stacked metasurface units, coupling slots, and feeding networks are arranged in a one-to-one correspondence; the feeding network couples energy to the corresponding stacked metasurface units through the coupling slots. This invention achieves unit miniaturization through stacked metasurfaces, and improves port isolation by combining with decoupling structures, thereby achieving stable two-dimensional wide-angle scanning with low scanning loss.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, specifically relating to millimeter-wave two-dimensional scanning phased array antennas. Background Technology

[0002] As next-generation wireless communication systems continue to evolve towards higher capacity, lower latency, and stronger scenario adaptability, millimeter-wave communication has attracted widespread attention due to its abundant available bandwidth resources. However, the millimeter-wave band suffers from problems such as high propagation loss, sensitivity to obstruction, and limited coverage. To address these issues, engineering systems typically employ high-gain array antennas and utilize phased array technology to achieve rapid beam pointing, thereby supporting two-dimensional scanning coverage.

[0003] To meet the coverage requirements of 2D scanning over a wide angular range, array designs typically require smaller element spacing, coupled with element miniaturization to accommodate the space and layout requirements of array implementation. However, as element spacing decreases, inter-element coupling increases, port isolation decreases, and active input impedance becomes more sensitive to changes in the scan angle. This can easily lead to deterioration of active return loss, decreased scan gain, and sidelobe lift and main lobe shift during large-angle scanning. Therefore, element miniaturization and array coupling suppression are fundamental to ensuring 2D scanning performance.

[0004] Metasurfaces, as designable artificial electromagnetic structures, offer a novel structural approach for array cell design. However, compared to traditional patch cells, metasurface cells have a more complex structural hierarchy, face stronger constraints on dimensional accuracy and feed layout, and are correspondingly more difficult to array. Therefore, how to effectively suppress array coupling and improve radiation performance in scanning mode while achieving cell miniaturization is a pressing technical problem to be solved in this field. Summary of the Invention

[0005] This invention provides a millimeter-wave two-dimensional scanning phased array antenna based on stacked metasurface units. The unit is miniaturized by stacked metasurfaces, and the port isolation is improved by decoupling structure. Stable two-dimensional wide-angle scanning with low scanning loss can be achieved.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The first aspect of the present invention provides a millimeter-wave two-dimensional scanning phased array antenna based on stacked metasurface units, comprising a first dielectric substrate, a second dielectric substrate, and a third dielectric substrate stacked together; a first metasurface structure is provided on the first dielectric substrate; a second metasurface structure is provided between the first dielectric substrate and the second dielectric substrate; the first metasurface structure and the second metasurface structure are aligned at their centers; the first metasurface structure and the second metasurface structure constitute a stacked metasurface unit; a plurality of stacked metasurface units are distributed in a rectangular array, and decoupling grounding branches are provided between adjacent stacked metasurface units;

[0008] A metal ground plane is provided between the second dielectric substrate and the third dielectric substrate, and a plurality of coupling gaps are provided on the metal ground plane; a plurality of power feeding networks are provided below the third dielectric substrate; the stacked metasurface units, coupling gaps and power feeding networks are arranged in a one-to-one correspondence; the power feeding network couples energy to the corresponding stacked metasurface units through the coupling gaps.

[0009] Furthermore, the overall dimensions of the first metasurface structure and the second metasurface structure are equal.

[0010] Furthermore, the first metasurface structure is a first metal patch distributed in an N×N rectangular array; the second metasurface structure is a second metal patch distributed in an M×M rectangular array; the size of the second metal patch is larger than that of the first metal patch.

[0011] Furthermore, the first metasurface structure is divided into M groups of k×k rectangular arrays of first metal patches. The k×k rectangular arrays of first metal patches are equal in size to and correspond vertically to a single second metal patch. Here, N = k×M, where N is the number of rows and columns of the first metal patches in the first metasurface structure, and M is the number of rows and columns of the second metal patches in the second metasurface structure.

[0012] Furthermore, the heights of the first and second metal patches are [0.05λ, 0.15λ], the width W1 of the first metal patch is [0.02λ, 0.12λ], the width W2 of the second metal patch is [0.08λ, 0.12λ], and the spacing Wh between the stacked metasurface units is [0.3λ, 0.55λ], where λ is the waveguide wavelength in the dielectric substrate.

[0013] Furthermore, the rectangular array composed of stacked metasurface units is distributed along the x-axis and y-axis directions; two decoupling grounding branches are set between two adjacent stacked metasurface units along the x-axis direction; the two decoupling grounding branches are parallel to each other.

[0014] Furthermore, the distance between the two decoupling grounding branches is equal to the width of the stacked metasurface unit, and the decoupling grounding branch is provided with two grounding metal posts, which are connected to the metal floor.

[0015] Furthermore, the height of the decoupling grounding stub is [0.01λ, 0.15λ], and the length is... The width is [0.1λ, 0.5λ]. The distance between the two grounding metal posts on the decoupling grounding branch is [0.01λ, 0.12λ]. The range is [0.28λ, 0.34λ], where λ is the waveguide wavelength in the dielectric substrate.

[0016] Furthermore, the shape of the decoupling grounding stub is set as follows: shape, shape, Shaped like an H, an X, or an L.

[0017] Furthermore, the coupling gap is set along the y-axis direction. Shaped gap.

[0018] Furthermore, the length of the coupling gap on the metal floor. The transverse slot width at both ends of the coupling gap is [0.14λ, 0.19λ]. The width of the transverse slot in the middle of the coupling gap is [0.03λ, 0.25λ]. The range is [0.01λ, 0.2λ], where λ is the waveguide wavelength in the dielectric substrate.

[0019] Furthermore, the power supply network is surrounded by a metal isolation structure; the metal isolation structure includes an isolation metal strip and a plurality of grounding metal posts; the isolation metal strip is arranged around the power supply network, and the plurality of grounding metal posts are evenly distributed on the isolation metal strip and connected to the metal grounding plate.

[0020] Furthermore, the step impedance linewidth in the feeder network The port stripline width is [0.01λ, 0.15λ]. The spacing dr between the grounding metal posts on the isolation metal strip is [0.01λ, 0.2λ]; the spacing dr between the grounding metal posts on the isolation metal strip is [0.03λ, 0.05λ]; the diameter d of the grounding metal posts is [0.01λ, 0.1λ]; and λ is the waveguide wavelength in the dielectric substrate.

[0021] Furthermore, each feed network is connected to an independent feed port, and the excitation amplitude of each independent feed port is kept consistent, and beam scanning is achieved by applying a phase gradient.

[0022] Furthermore, the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are low-temperature co-fired ceramic substrates or PCB dielectric substrates.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] The present invention provides a first metasurface structure on the first dielectric substrate; a second metasurface structure is provided between the first dielectric substrate and the second dielectric substrate; the first and second metasurface structures are aligned at their centers; the first and second metasurface structures form a stacked metasurface unit; a plurality of stacked metasurface units are distributed in a rectangular array to form a stacked metasurface structure, and additional interlayer capacitance is introduced through the stacked metasurface structure, which significantly reduces the planar size of the stacked metasurface unit while maintaining the original resonant characteristics and operating bandwidth, providing space for compact array layout and decoupling structure loading.

[0025] This invention introduces decoupling grounding stubs between adjacent stacked metasurface units in the array. The additional coupling of the decoupling grounding stubs cancels out the inherent coupling of the antenna, effectively improving port isolation and reducing active return loss during scanning. Attached Figure Description

[0026] Figure 1 This is a structural diagram of the millimeter-wave two-dimensional scanning phased array antenna provided in Embodiment 1 of the present invention;

[0027] Figure 2 This is a structural diagram of the stacked metasurface structure provided in Embodiment 1 of the present invention;

[0028] Figure 3 This is a top view of the upper surface of the power supply network layer provided in Embodiment 1 of the present invention;

[0029] Figure 4 This is a structural diagram of the metal isolation structure provided in Embodiment 1 of the present invention;

[0030] Figure 5 This is a structural diagram of the decoupling grounding branch provided in Embodiment 1 of the present invention.

[0031] Figure 6 This is a diagram showing the isolation performance of the phased array antenna after decoupling, as provided in Embodiment 1 of the present invention.

[0032] Figure 7 This is a scan result diagram of the phased array antenna at 37GHz with an E-plane ±55° angle provided in Embodiment 1 of the present invention;

[0033] Figure 8 This is a scan result diagram of the phased array antenna at 39.5GHz with an E-plane ±54° angle provided in Embodiment 1 of the present invention;

[0034] Figure 9This is a scanning result diagram of the phased array antenna at 42GHz with an E-plane ±51° angle provided in Embodiment 1 of the present invention;

[0035] Figure 10 This is a scan result diagram of the phased array antenna at 37GHz with an H-plane ±50° angle provided in Embodiment 1 of the present invention;

[0036] Figure 11 This is a scan result diagram of the phased array antenna at 39.5GHz with an H-plane ±50° angle provided in Embodiment 1 of the present invention;

[0037] Figure 12 This is a scan result diagram of the phased array antenna provided in Embodiment 1 of the present invention at 42GHz with H-plane ±50° scanning effect;

[0038] In the figure, 1 is a stacked metasurface unit, 2 is the first layer metasurface structure, 3 is the second layer metasurface structure, 4 is a metal ground plane, 5 is an isolation metal strip, 6 is a coupling gap, 7 is a grounding metal post, 8 is a metal isolation structure, 9 is a power supply network, and 10 is an independent power supply port. Detailed Implementation

[0039] 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.

[0040] 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.

[0041] like Figure 1 As shown, this embodiment provides a millimeter-wave two-dimensional scanning phased array antenna based on stacked metasurface units, including a first dielectric substrate, a second dielectric substrate, and a third dielectric substrate stacked together; the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are low-temperature co-fired ceramic substrates or PCB dielectric substrates.

[0042] like Figure 2As shown, a first metasurface structure 2 is provided on the first dielectric substrate; a second metasurface structure 3 is provided between the first dielectric substrate and the second dielectric substrate; the overall dimensions of the first metasurface structure 2 and the second metasurface structure 3 are equal; the first metasurface structure 2 and the second metasurface structure 3 are aligned at their centers; the first metasurface structure 2 and the second metasurface structure 3 form a stacked metasurface unit 1.

[0043] The first metasurface structure 2 is a first metal patch distributed in an N×N rectangular array; the second metasurface structure 3 is a second metal patch distributed in an M×M rectangular array; the size of the second metal patch is larger than that of the first metal patch.

[0044] The first metasurface structure 2 is divided into M groups of k×k rectangular arrays of first metal patches. The k×k rectangular array of first metal patches has the same size as a single second metal patch and they correspond vertically. N represents the number of rows and columns of the first metal patch in the first metasurface structure 2, and M represents the number of rows and columns of the second metal patch in the second metasurface structure 3.

[0045] The heights of the first and second metal patches are [0.05λ, 0.15λ], the width W1 of the first metal patch is [0.02λ, 0.12λ], the width W2 of the second metal patch is [0.08λ, 0.12λ], and the spacing Wh between the stacked metasurface units is [0.3λ, 0.55λ], where λ is the waveguide wavelength in the dielectric substrate.

[0046] The stacked metasurface unit 1 can reduce the size of the radiating element while maintaining the resonant characteristics within the target frequency band through the interlayer coupling effect between the upper and lower metasurfaces, thereby realizing the miniaturization design of the antenna element.

[0047] In this embodiment, the longitudinal direction of the dielectric substrate is taken as the x-axis direction, the transverse direction of the dielectric substrate is taken as the y-axis direction, and the thickness direction of the dielectric substrate is set as the z-axis direction to establish a three-dimensional rectangular coordinate system; a number of stacked metasurface units 1 are distributed in a rectangular array, and the rectangular array composed of stacked metasurface units 1 is distributed along the x-axis and y-axis directions; the array of stacked metasurface units 1 can adopt a more compact arrangement, which is beneficial to realizing large-angle scanning.

[0048] Two decoupling grounding stubs 11 are arranged between two adjacent stacked metasurface units 1 along the x-axis direction; the two decoupling grounding stubs 11 are parallel to each other; the distance between the two decoupling grounding stubs 11 is equal to the width of the stacked metasurface unit 1; each decoupling grounding stub 11 is provided with two grounding metal posts 7, which are connected to a metal grounding plate 4; the shape of the decoupling grounding stub 11 is set as follows: shape, shape, Shaped, H-shaped, X-shaped, or L-shaped; in this embodiment, the decoupling grounding branch uses the following shape: shape.

[0049] like Figure 5 As shown, the height of the decoupling grounding stub is [0.01λ, 0.15λ], and the length is... The width is [0.1λ, 0.5λ]. The distance between the two grounding metal posts on the decoupling grounding branch is [0.01λ, 0.12λ]. The range is [0.28λ, 0.34λ], where λ is the waveguide wavelength in the dielectric substrate.

[0050] In this embodiment, because the electromagnetic coupling between adjacent stacked metasurface units is significantly enhanced under compact arrangement conditions, a π-shaped decoupling grounding stub is introduced into the stacked metasurface unit array to improve the isolation performance between adjacent ports. The π-shaped decoupling grounding stub is disposed between adjacent stacked metasurface units 1 on the E plane. By adjusting the height, length, and width of the decoupling grounding stub 11 and the relative spacing of the grounding metal pillars 7, the phase and amplitude of the introduced decoupling path can be adjusted to cancel out the inherent coupling path, thereby reducing the coupling level between adjacent stacked metasurface units, improving the array port isolation, and improving the active matching characteristics in the scanning state.

[0051] The metal floor 4 is disposed between the second dielectric substrate and the third dielectric substrate, and the metal floor is provided with a plurality of coupling gaps 6; a plurality of power feeding networks 9 are provided below the third dielectric substrate; the stacked metasurface unit 1, the coupling gaps 6 and the power feeding network 9 are arranged in a one-to-one correspondence; the transmission line of the power feeding network 9 adopts the form of a grounded coplanar waveguide, and the power feeding network 9 couples energy to the corresponding stacked metasurface unit 1 through the coupling gaps 6;

[0052] The coupling gap 6 is set along the y-axis direction. Shaped gap; length of coupling gap on metal floor 4 The transverse slot width at both ends of the coupling gap is [0.14λ, 0.19λ]. The width of the transverse slot in the middle of the coupling gap is [0.03λ, 0.25λ]. The range is [0.01λ, 0.2λ], where λ is the waveguide wavelength in the dielectric substrate.

[0053] like Figure 3As shown, a metal isolation structure 8 is provided around the feed network 9 to constrain the electromagnetic field distribution in the feed area and reduce the impact of parasitic resonance on antenna performance. The metal isolation structure 8 includes an isolation metal strip 5 and several grounded metal pillars 7. The isolation metal strip 5 is arranged around the feed network 9, and the several grounded metal pillars 7 are evenly distributed on the isolation metal strip 5 and connected to the metal ground plane 4. Each feed network is connected to an independent feed port 10, and the excitation amplitude of each independent feed port 10 is kept consistent and beam scanning is achieved by applying a phase gradient.

[0054] like Figure 4 As shown, the width of the step impedance line in the feeder network The port stripline width is [0.01λ, 0.15λ]. The spacing dr between the grounding metal posts on the isolation metal strip is [0.01λ, 0.2λ]; the spacing dr between the grounding metal posts on the isolation metal strip is [0.03λ, 0.05λ]; the diameter d of the grounding metal posts is [0.01λ, 0.1λ]; and λ is the waveguide wavelength in the dielectric substrate.

[0055] This invention employs a stacked metasurface structure to form a compactly arranged millimeter-wave phased array. While reducing the unit size, it provides space for loading decoupling structures within the array, thus achieving a balance between high isolation, low active return loss, and wide-angle scanning performance. It maintains good wide-angle scanning capability in both the E and H planes within the operating frequency band, with scanning loss controlled within 3 dB, small main lobe gain variation, and stable radiation performance. Furthermore, it possesses good fabrication and scalability, and can be applied to the design of metasurface array antennas with different numbers of layers and different feeding methods.

[0056] The millimeter-wave two-dimensional scanning phased array antenna based on stacked metasurface units in this embodiment has the following specific dimensions:

[0057] The height of the first and second metal patches is 0.658 mm. The width W1 of the first metal patch is 0.22 mm, and the width W2 of the second metal patch is 0.65 mm. The spacing between the stacked metasurface units is W. h The I-shaped gap length lw2 on the metal floor is 1.25mm, the width of the horizontal groove at both ends of the I-shaped gap on the metal floor is 0.3mm, and the width of the horizontal groove in the middle of the I-shaped gap is 0.11mm.

[0058] In feeder network 9, the width of the step impedance line fw1 is 0.15 mm, the width of the port stripline fw0 is 0.1 mm, the spacing dr between the grounding metal posts on the isolation metal strip is 0.3 mm, and the diameter d is 0.1 mm. The height of the decoupling grounding branch is 0.658 mm, the length pl of the decoupling grounding branch is 1.8 mm, the width pw of the decoupling grounding branch is 0.1 mm, the spacing pa between the two grounding metal posts on the decoupling grounding branch is 1.5 mm, and the distance between the grounding metal post and the decoupling grounding branch is 0.2 mm.

[0059] like Figure 6 As shown, the millimeter-wave phased array antenna based on stacked metasurface elements operates in the 37–42 GHz frequency band, exhibiting good in-band matching performance and an isolation greater than 20 dB between adjacent ports. The use of stacked metasurface elements allows for a more compact array arrangement. After adding decoupling grounding stubs, the isolation between adjacent ports is improved, thus enhancing the array's radiation performance.

[0060] like Figure 7 , Figure 8 and Figure 9 As shown, the millimeter-wave phased array antenna exhibits good wide-angle scanning capability in the E-plane. Specifically, the maximum scanning angle is ±55° at 37 GHz, with a gain drop of 1.5 dB; at 39.5 GHz, the maximum scanning angle is ±54°, with a gain drop of 1.8 dB; and at 42 GHz, the maximum scanning angle is ±51°, with a gain drop of 1.5 dB.

[0061] like Figure 10 , Figure 11 and Figure 12 As shown, the millimeter-wave phased array antenna also exhibits good wide-angle scanning capability in the H-plane. At the three frequency points of 37 GHz, 39.5 GHz, and 42 GHz, the maximum scanning angle is ±50°, with gain drops of 2.3 dB, 2.8 dB, and 1.8 dB, respectively.

[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. A millimeter-wave two-dimensional scanning phased array antenna based on stacked metasurface units, characterized in that, The device includes a first dielectric substrate, a second dielectric substrate, and a third dielectric substrate stacked together; a first metasurface structure is provided on the first dielectric substrate; a second metasurface structure is provided between the first and second dielectric substrates; the first and second metasurface structures are aligned at their centers. The first layer metasurface structure and the second layer metasurface structure form a stacked metasurface unit; a plurality of stacked metasurface units are distributed in a rectangular array, and decoupling grounding branches are arranged between two adjacent stacked metasurface units; A metal ground plane is provided between the second dielectric substrate and the third dielectric substrate, and a plurality of coupling gaps are provided on the metal ground plane; a plurality of power feeding networks are provided below the third dielectric substrate; the stacked metasurface units, coupling gaps and power feeding networks are arranged in a one-to-one correspondence; the power feeding network couples energy to the corresponding stacked metasurface units through the coupling gaps.

2. The millimeter-wave two-dimensional scanning phased array antenna according to claim 1, characterized in that, The first metasurface structure and the second metasurface structure have the same overall size; the first metasurface structure is a first metal patch distributed in an N×N rectangular array; the second metasurface structure is a second metal patch distributed in an M×M rectangular array. The second metal patch is larger than the first metal patch.

3. The millimeter-wave two-dimensional scanning phased array antenna according to claim 2, characterized in that, The first metasurface structure is divided into M groups of k×k rectangular arrays of first metal patches. The size of the k×k rectangular array of first metal patches is equal to that of a single second metal patch and they are vertically aligned. Here, N=k×M, where N is the number of rows and columns of the first metal patches in the first metasurface structure, and M is the number of rows and columns of the second metal patches in the second metasurface structure.

4. The millimeter-wave two-dimensional scanning phased array antenna according to claim 2, characterized in that, The heights of the first and second metal patches are [0.05λ, 0.15λ], the width W1 of the first metal patch is [0.02λ, 0.12λ], the width W2 of the second metal patch is [0.08λ, 0.12λ], and the spacing Wh between the stacked metasurface units is [0.3λ, 0.55λ], where λ is the waveguide wavelength in the dielectric substrate.

5. The millimeter-wave two-dimensional scanning phased array antenna according to claim 1, characterized in that, A rectangular array of stacked metasurface units is distributed along the x-axis and y-axis; two decoupling grounding stubs are set between two adjacent stacked metasurface units along the x-axis; the two decoupling grounding stubs are parallel to each other; The distance between the two decoupling grounding branches is equal to the width of the stacked metasurface unit. The decoupling grounding branch is provided with two grounding metal posts, which are connected to the metal floor.

6. The millimeter-wave two-dimensional scanning phased array antenna according to claim 5, characterized in that, The height of the decoupling grounding stub is [0.01λ, 0.15λ], and the length is... The width is [0.1λ, 0.5λ]. The distance between the two grounding metal posts on the decoupling grounding branch is [0.01λ, 0.12λ]. The range is [0.28λ, 0.34λ], where λ is the waveguide wavelength in the dielectric substrate.

7. The millimeter-wave two-dimensional scanning phased array antenna according to claim 5, characterized in that, The coupling gap is positioned along the y-axis direction. Shaped gap, coupling gap length on metal floor The transverse slot width at both ends of the coupling gap is [0.14λ, 0.19λ]. The width of the transverse slot in the middle of the coupling gap is [0.03λ, 0.25λ]. The range is [0.01λ, 0.2λ], where λ is the waveguide wavelength in the dielectric substrate.

8. The millimeter-wave two-dimensional scanning phased array antenna according to claim 1, characterized in that, The power supply network is surrounded by a metal isolation structure; the metal isolation structure includes an isolation metal strip and a number of grounding metal posts; the isolation metal strip is arranged around the power supply network, and the number of grounding metal posts are evenly distributed on the isolation metal strip and connected to the metal grounding plate.

9. The millimeter-wave two-dimensional scanning phased array antenna according to claim 8, characterized in that, Step impedance line width in feeder network The port stripline width is [0.01λ, 0.15λ]. The range is [0.01λ, 0.2λ]. The spacing dr of the grounding metal posts on the isolation metal strip is [0.03λ, 0.05λ], and the diameter d of the grounding metal posts is [0.01λ, 0.1λ], where λ is the waveguide wavelength in the dielectric substrate.

10. The millimeter-wave two-dimensional scanning phased array antenna according to claim 1, characterized in that, Each feed network is connected to an independent feed port. The excitation amplitude of each independent feed port is kept consistent, and beam scanning is achieved by applying a phase gradient.

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