A windmill-shaped metasurface antenna with broadband stable radiation characteristics

Abstract

The application discloses a windmill type metasurface antenna with wideband stable radiation characteristics in the field of antennas, which comprises an upper dielectric substrate and a lower dielectric substrate arranged in a stack; a metal ground plate is arranged between the upper dielectric substrate and the lower dielectric substrate; the metal ground plate is provided with a coupling gap; a feed network for inputting energy to the coupling gap is arranged at the bottom of the lower dielectric substrate; a windmill type metasurface structure is arranged on one side of the upper dielectric substrate; the windmill type metasurface structure comprises a plurality of windmill type metal patches; sawtooth-shaped gaps are arranged between the windmill type metal patches, and the windmill type metal patches are arranged in a central symmetry; and the application realizes a novel windmill type metasurface structure by etching the sawtooth-shaped gaps, and has the characteristics of wideband, stable radiation characteristics, compact size and simple structure.

Description

Technical Field

[0001] This invention belongs to the field of broadband antenna technology, specifically relating to a windmill-type metasurface antenna with broadband stable radiation characteristics. Background Technology

[0002] With the rapid development of communication technology, antennas with low profile, wide bandwidth, stable radiation, high gain, and small size have increasingly become a research hotspot in the field of wireless communication. Among them, microstrip patch antennas are the simplest and most popular form of low-profile antennas. These antennas have advantages such as low profile, light weight, low cost, and easy compatibility with printed circuits. However, their impedance bandwidth is relatively narrow and their gain is relatively low. Although many technologies have been developed to overcome this shortcoming, such as adding U-shaped slots, adding parasitic structures, using non-contact capacitive feeding, adding back cavities, or increasing the thickness of the dielectric substrate, these methods also have problems such as limited bandwidth improvement or overly complex structures.

[0003] In addition, in recent years, metasurfaces (MS) have been widely used in antennas to improve performance due to their unique electromagnetic properties that allow for the manipulation of electromagnetic waves. Therefore, metasurfaces are also frequently used to increase the gain or bandwidth of microstrip patch antennas. For example, by using mushroom-shaped, grid-like, or rhomboid metasurface structures and arranging metasurface elements in an array, varying degrees of improvement in impedance bandwidth or high gain at a single frequency point can be achieved, showing great promise. However, these methods cannot achieve highly stable radiation characteristics over a wide frequency range, which remains a technical challenge for broadband metasurface antennas. Summary of the Invention

[0004] The purpose of this invention is to provide a windmill-shaped metasurface antenna with broadband stable radiation characteristics. It employs a novel windmill-shaped metasurface structure, constructing a metasurface structure with broadband stable radiation characteristics through etching sawtooth-shaped slots. Applying this structure to antenna design enables highly stable radiation characteristics over a wide frequency range. Compared to traditional metasurface antennas, this invention features broadband performance, stable radiation, compact size, and simple structure.

[0005] To achieve the above objectives, the first technical solution adopted by the present invention is:

[0006] A windmill-shaped metasurface antenna with broadband stable radiation characteristics includes an upper dielectric substrate and a lower dielectric substrate stacked together; a metal ground plane is disposed between the upper and lower dielectric substrates; the metal ground plane is provided with coupling slots; a feed network for inputting energy to the coupling slots is disposed at the bottom of the lower dielectric substrate; and a windmill-shaped metasurface structure is disposed on one side of the upper dielectric substrate.

[0007] The windmill-shaped metasurface structure includes several windmill-shaped metal patches arranged in an array along the x-axis and y-axis; etched gaps are provided between the windmill-shaped metal patches, and the windmill-shaped metal patches themselves are arranged in a centrally symmetrical manner.

[0008] Preferably, the outlines of the adjacent wind turbine patch units fit each other, and the arrayed wind turbine patch units are spliced ​​together to form a surface.

[0009] Preferably, the metal floor has a coupling gap.

[0010] Preferably, the etched gaps are serrated.

[0011] Preferably, the power supply network intersects the vertical projection of the coupling gap; the input end of the power supply network is configured as a Y-shaped microstrip line; the microstrip line is disposed on the side of the lower dielectric substrate away from the upper dielectric substrate.

[0012] Preferably, the dielectric constants of the upper dielectric substrate and the lower dielectric substrate are [2.2, 10.2], and the thickness h1 of the upper dielectric substrate and the thickness h2 of the lower dielectric substrate are in the range of [0.001λ0, 0.2λ0]; λ0 is the free space wavelength.

[0013] Preferably, the width g of the serrated etched gap between two adjacent windmill metal patches is [0.001λ0, 0.05λ0].

[0014] Preferably, the center-to-center spacing d of the windmill-shaped metal patches is [0.05λ0, 0.4λ0].

[0015] Preferably, the side length G of the metal floor is... L The range is [0.3λ0, λ0]; the total length of the coupling gap is 2×(L s1 +L S2 The total length of the coupling gap ranges from [0.1λ]. g 0.6λ g The width Ws1 at the widest point of the coupling gap ranges from [0.05λg, 0.4λg], and the width Ws2 at the narrowest point ranges from [0.01λg, 0.2λg], where λg is the effective wavelength of the dielectric on the upper dielectric substrate, and n is the number of coupling gaps in the metal ground plane; L s1 L represents the length corresponding to the widest point of a single coupling gap. s2 It represents the length corresponding to the narrowest point of a single coupling gap.

[0016] Preferably, the width wf of the Y-shaped microstrip line is [0.1λg1, 0.5λg1], and the length S of the upper part of the Y-shape is [0.2λg1, λg1], where λg1 is the effective wavelength of the dielectric substrate of the lower layer.

[0017] Furthermore, the present invention provides an improved metasurface antenna scheme:

[0018] Since the surface current in the outer part of the metasurface antenna is weak after feeding, its impact on the overall radiation of the antenna is not significant. To further improve the radiation efficiency, the antenna size was modified by cutting the edge of the windmill-shaped metasurface antenna, thus constructing a compact metasurface antenna with wide bandwidth and stable radiation.

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0020] The windmill-shaped metasurface structure described in this invention comprises a plurality of windmill-shaped metal patches; serrated etched gaps are provided between the windmill-shaped metal patches, and the windmill-shaped metal patches themselves are arranged in a centrally symmetrical manner. The serrated etched gaps between the metasurface metal patches can be regarded as smooth transmission lines, which on the one hand makes the current path smoother, and on the other hand makes the impedance change very small, thereby realizing the broadband stable radiation characteristics of the metasurface structure; at the same time, this invention has the characteristics of compact size, simple structure and low processing cost, which is conducive to mass production. Attached Figure Description

[0021] Figure 1 This is a top view of a windmill-type metasurface antenna with broadband stable radiation characteristics provided by the present invention.

[0022] Figure 2 This is a structural diagram of a windmill-type metasurface antenna with broadband stable radiation provided in Embodiment 1 of the present invention;

[0023] Figure 3 This is a structural diagram of the metal floor provided in Embodiment 1 of the present invention;

[0024] Figure 4 This is a structural diagram of the etching gap and power supply network provided in Embodiment 1 of the present invention;

[0025] Figure 5 This is a model coefficient diagram of the metasurface structure of the wind turbine model in this invention;

[0026] Figure 6 It is based on the present invention Figure 1 Current distribution diagram of the metasurface antenna;

[0027] Figure 7 It is based on the present invention Figure 1 The radiation pattern of the metasurface antenna;

[0028] Figure 8 This is a diagram of the improved antenna structure provided in Embodiment 2 of the present invention;

[0029] Figure 9 Fig. 11 shows the impedance matching characteristic diagram and simulation gain analysis diagram of Embodiment 2 of this invention.

[0030] In the figure: 1 Upper dielectric substrate, 2 Lower dielectric substrate, 3 Windmill-shaped metal patch, 4 Coupling gap, 5 Metal floor, 6 Microstrip line, 7 Serrated etched gap, 8 Metasurface structure. Detailed Implementation

[0031] 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.

[0032] 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.

[0033] Example 1

[0034] like Figures 1 to 4 As shown, a windmill-type metasurface antenna with broadband stable radiation characteristics includes an upper dielectric substrate 1 and a lower dielectric substrate 2 stacked together; a metal ground plane 5 is disposed between the upper dielectric substrate 1 and the lower dielectric substrate 2; the metal ground plane 5 has one or two coupling slots 4; a feeding network for inputting energy to the coupling slots 4 is disposed at the bottom of the lower dielectric substrate 2; the feeding network intersects the vertical projection of the coupling slots; the feeding network is configured as a Y-shaped microstrip line 6; the Y-shaped microstrip line 6 is disposed on the side of the lower dielectric substrate 2 away from the upper dielectric substrate 1, the width wf of the microstrip line 6 is [0.1λg1, 0.5λg1], and the length S of the upper part of the Y-shape is [0.2λg1, λg1], where λg1 is the effective wavelength of the dielectric of the lower dielectric substrate.

[0035] A windmill-shaped metasurface structure 8 is disposed on the side of the upper dielectric substrate 1 away from the lower dielectric substrate 2; a plurality of windmill-shaped metasurface metal patches 3 are disposed on the windmill-shaped metasurface structure 8, the contours of adjacent windmill-shaped patches 3 fit each other, and each windmill-shaped metasurface metal patch 3 is arranged in an array along the x-axis and y-axis directions and is centrally symmetrical; a serrated etching gap 7 is disposed between two windmill-shaped metasurface metal patches 3; the serrated etching gap 7 is inclined relative to the x-axis and y-axis; the serrated etching gap between the windmill-shaped metasurface metal patches 3 makes the current path smoother on the one hand, and makes the impedance change smaller on the other hand, thereby realizing the broadband stable radiation characteristics of the metasurface structure.

[0036] The dielectric constants of the upper dielectric substrate 1 and the lower dielectric substrate 2 are [2.2, 10.2], the thickness h1 of the upper dielectric substrate 1 and the thickness h2 of the lower dielectric substrate 2 are in the range of [0.001λ0, 0.1λ0], λ0 is the free space wavelength, the serrated gap width g between two adjacent windmill-shaped metasurface metal patches is [0.001λ0, 0.05λ0], and the center-to-center spacing d of the windmill-shaped metal patches is [0.05λ0, 0.4λ0].

[0037] The side length G of the metal floor L The range is [0.3λ0, λ0]; the total length of the coupling gap is 2×(L S1 +L S2 The total length of the coupling gap ranges from [0.1λ]. g 0.6λ g The width Ws1 at the widest point of the coupling gap ranges from [0.05λg, 0.4λg], and the width Ws2 at the narrowest point ranges from [0.01λg, 0.2λg], where λg is the effective wavelength of the dielectric on the upper dielectric substrate, and n is the number of coupling gaps in the metal ground plane; L s1 L represents the length corresponding to the widest point of a single coupling gap. s2 It represents the length corresponding to the narrowest point of a single coupling gap.

[0038] The width wf of the Y-shaped microstrip line is [0.1λg1, 0.5λg1]; the length S of the upper part of the Y-shape is [0.2λg1, λg1], where λg1 is the effective wavelength of the dielectric substrate of the lower layer.

[0039] In this embodiment, the specific parameters are set as follows: the thickness h1 of the upper dielectric substrate 1 is 3.25 mm, and the thickness h2 of the lower dielectric substrate 2 is 0.813 mm; the width g of the serrated etched gap between two adjacent windmill-shaped metasurface metal patches 3 is 0.5 mm, and the center-to-center distance d is 6.63 mm; the side length G of the metal floor 5 is... LThe length is 20mm; the total length of the coupling gap 4 opened on the metal floor is 16.2mm, the width Ws1 at the widest point is 1.2mm, and the corresponding length L is 20mm. S1 The width at its narrowest point, Ws2, is 3.5mm, and the corresponding length, L, is 0.7mm. S2 The width wf of the Y-shaped microstrip line 6 is 1.85mm, and the length S of the upper part of the Y-shape is 5mm.

[0040] like Figure 5 As shown, the resonance and radiation characteristics of the antenna can be obtained by analyzing the mode coefficient diagram of a 4×4 windmill-type metasurface element array. Modes J1 and J2 both have a resonant frequency of 6 GHz, and their mode coefficient curves completely overlap, indicating that they have the same resonance and radiation characteristics and are a pair of orthogonal modes. Modes J3 and J4 both have a resonant frequency of 6.9 GHz, and their mode coefficient curves are similar but not identical. The portion of the mode coefficient greater than 0.707 is called the radiation bandwidth of the mode. The bandwidth range of J1 and J2 is 5.29–8.43 GHz, with a relative bandwidth of 45.9%, showing that modes J1 and J2 have good broadband radiation characteristics.

[0041] like Figures 6 to 7 As shown, the current distribution and radiation pattern of mode J1 at different frequencies are illustrated. Observations were conducted at 5 GHz, 6 GHz, 7 GHz, and 8 GHz within the bandwidth range. The current distribution and radiation direction of mode J1 remained stable at the corresponding frequencies. This indicates that the mode can radiate over a wide frequency band with very stable radiation characteristics, which can be used to design broadband antennas with stable radiation features.

[0042] Example 2

[0043] This embodiment provides an improved windmill metasurface antenna with broadband stable radiation characteristics. The difference between this embodiment and Embodiment 1 is that... Figure 8 As shown, the metasurface structure is an improved windmill metasurface structure. It is created by cutting the edge metal portion based on the windmill metasurface structure of Example 1, resulting in a total side length G of the overall metasurface structure. M The surface current in the outer part of the metasurface structure is relatively weak, which has little impact on the radiation characteristics of the antenna. Therefore, the cut metasurface structure can still meet the bandwidth and radiation characteristics requirements of the metasurface antenna, making the antenna compact, simple in structure and low in processing cost, which is conducive to mass production.

[0044] like Figure 9 As shown, the impedance matching characteristics and simulation gain analysis of the improved metasurface antenna provided in Example 2 are illustrated. It can be seen that |S 11The operating impedance bandwidth of -10dB is approximately 50.5% (5.12–8.58 GHz). The achieved gain curve is very stable across the entire operating impedance bandwidth. The peak achieved gain is approximately 6.53 dBi (at 6.6 GHz), with a gain variation of approximately 1.55 dB within the operating band. Therefore, the metasurface antenna provided in Embodiment 2 can effectively achieve broadband and radiation-stable characteristics.

[0045] Example 3

[0046] A method for fabricating a metasurface antenna with broadband stable radiation characteristics. The fabrication method provided in this embodiment can be applied to the compact metasurface antenna with broadband stable radiation described in Embodiment 1. The fabrication method includes:

[0047] Based on the bandwidth and radiation characteristics requirements of the metasurface antenna, the edge portion of the wind turbine metasurface structure is cut and the total side length G of the wind turbine metasurface structure is adjusted. M By cutting the edge portion of the windmill-shaped metasurface structure, the total side length G of the windmill-shaped metasurface structure is adjusted. M Modifying the dimensions of the metasurface structure to meet the bandwidth and radiation characteristics requirements of the metasurface antenna results in an antenna with compact size, simple structure, and low processing cost, which is conducive to mass production.

[0048] 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 windmill-type metasurface antenna with broadband stable radiation characteristics, characterized in that, The device includes an upper dielectric substrate and a lower dielectric substrate stacked together; a metal ground plane is disposed between the upper dielectric substrate and the lower dielectric substrate; the metal ground plane is provided with coupling gaps; a power supply network for inputting energy to the coupling gaps is disposed at the bottom of the lower dielectric substrate; and a metasurface structure is disposed on the side of the upper dielectric substrate away from the lower dielectric substrate. The metasurface structure is provided with several windmill-shaped metasurface metal patches, each windmill-shaped metasurface metal patch along... x Axial direction and y The array is distributed along the axial direction; the metal patches of the wind turbine model are provided with serrated gaps between them, and the metal patches themselves are arranged in a centrally symmetrical manner; the bending angle of the serrated gaps is an obtuse angle, and the serrated gaps are used to make the metasurface structure itself have broadband and stable radiation characteristics; the contours of adjacent wind turbine model patch units fit each other, and the arrayed wind turbine model patch units are spliced ​​together to form a surface.

2. The windmill-type metasurface antenna with broadband stable radiation characteristics according to claim 1, characterized in that, The metal floor has one, two, or more coupling gaps for exciting the upper wind turbine metasurface structure; the coupling gaps can be rectangular gaps or stepped gaps.

3. A windmill-type metasurface antenna with broadband stable radiation characteristics according to claim 1, characterized in that, The power supply network intersects the vertical projection of the coupling gap; the input end of the power supply network is set as a metal strip-shaped microstrip line; the output end of the power supply network extending to the coupling gap can be rectangular, Y-shaped or fan-shaped, used to adjust impedance matching; the microstrip line is located on the side of the lower dielectric substrate away from the upper dielectric substrate.

4. A windmill-type metasurface antenna with broadband stable radiation characteristics according to any one of claims 1 to 3, characterized in that, The dielectric constants of the upper and lower dielectric substrates are [2.2, 10.2], and the thickness of the upper dielectric substrate is... h 1. Thickness of the underlying dielectric substrate h 2. The range is [0.001]. λ 0,0.2 λ 0]; λ 0 represents the wavelength in free space.

5. A windmill-type metasurface antenna with broadband stable radiation characteristics according to claim 4, characterized in that, The width of the serrated gap between two adjacent windmill metasurface metal patches g [0.001] λ 0,0.05 λ 0]; Center-to-center spacing of windmill metal patches d [0.05] λ 0,0.4 λ 0].

6. A windmill-type metasurface antenna with broadband stable radiation characteristics according to claim 4, characterized in that, Side length of metal floor G L The range is [0.3]. λ 0, λ 0]; The total length range of the coupling gap is [0.1]. λ g 0.6 λ g The width range of the coupling gap is [0.05]. λ g 0.4 λ g ],in, λ g This refers to the effective wavelength of the dielectric substrate in the upper layer.

7. A windmill-type metasurface antenna with broadband stable radiation characteristics according to claim 1, characterized in that, The width of the microstrip line at the input of the feed network wf For [0.1] λg 1,0.5 λg 1]; The length of the Y-shaped upper end of the output end of the feed network extending to the coupling gap portion. S For [0.2] λg 1, λg 1], of which λg 1 represents the effective wavelength of the dielectric substrate in the lower layer.

Images