Negative phase gradient metasurface structure

Abstract

The application discloses a negative phase gradient metasurface structure, which comprises a feeding structure and a negative phase gradient metasurface unit structure, wherein the negative phase gradient metasurface unit structure is embedded on the top of the feeding structure. According to the principle of the Babinet, the negative phase gradient metasurface unit structure is complementary to the conventional phase gradient metasurface unit structure, the originally non-metallic part is filled with metal, and the principle of slot radiation is introduced into the phase gradient metasurface, so that the radiated electromagnetic wave can be regulated. The negative phase gradient metasurface unit structure is composed of units with different sizes. The results show that the negative phase gradient metasurface has similar characteristics to the conventional phase gradient metasurface, that is, the directional diagram has a scanning characteristic with the change of the frequency within the impedance bandwidth range, and the directivity of the slot unit radiation can be improved if the array is reasonably composed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of radio frequency antennas, in particular to a back side phase gradient metasurface structure. BACKGROUND

[0002] Phase gradient metasurfaces have attracted the interest of a large number of researchers due to their good electromagnetic characteristics, and in particular, the use of phase gradient metasurfaces as radiators to form new antennas is becoming a research hotspot. At present, the feeding technology for using conventional phase gradient metasurfaces as radiators includes rectangular waveguide, corrugated metal strip, parallel plate waveguide and planar horn, etc. The feeding technology has high requirements and low coupling efficiency. SUMMARY

[0003] The purpose of the present application is to provide a back side phase gradient metasurface structure, which aims to solve the problem of high requirements and low coupling efficiency of conventional phase gradient metasurfaces in the prior art.

[0004] To achieve the above purpose, the present application provides a back side phase gradient metasurface structure, which comprises a feeding structure and a back side phase gradient metasurface unit structure, wherein the back side phase gradient metasurface unit structure is embedded in the top of the feeding structure.

[0005] The back side phase gradient metasurface unit structure comprises a first back side unit, a second back side unit and a third back side unit, wherein the first back side unit, the second back side unit and the third back side unit are embedded in the top of the feeding structure in sequence, and the first back side unit, the second back side unit and the third back side unit are located on the central axis of the wide side of the top of the feeding structure.

[0006] The feeding structure comprises an SMA connector and a waveguide, the material of the waveguide is metal, the waveguide has a containing cavity inside, the waveguide and the containing cavity are both cuboids, one end of the SMA connector is embedded in the bottom of the waveguide, and one end of the feeding probe of the SMA connector penetrates through the bottom of the waveguide and is located inside the containing cavity.

[0007] The inside of the containing cavity is filled with air.

[0008] The thickness of the first back side unit, the thickness of the second back side unit and the thickness of the third back side unit are all the same as the distance from the top of the waveguide to the inner top wall of the containing cavity.

[0009] The distance between the second back side unit and the first back side unit is 14mm, and the distance between the second back side unit and the third back side unit is 14mm.

[0010] The length of the waveguide is 61mm, the width is 20mm and the height is 7mm.

[0011] The distance from the waveguide top to the inner top wall of the accommodating cavity is 1mm.

[0012] The beneficial effects of the present application: according to the principle of Babinet, the present application proposes a said negative phase gradient metasurface structure which is complementary to the conventional phase gradient metasurface structure, that is, the metal part in the original conventional unit is removed, and the original non-metal part is filled with metal, the principle of slot radiation is introduced into the phase gradient metasurface, and the electromagnetic wave can be regulated. The simulation results show that the negative phase gradient metasurface has similar electromagnetic characteristics as the traditional phase gradient metasurface, and the directivity of the slot unit radiation can be improved if the array is reasonably composed. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0014] Figure 1 is a three-dimensional structure schematic diagram of the negative phase gradient metasurface structure provided by the present application.

[0015] Figure 2 is a top view of the negative phase gradient metasurface structure provided by the present application.

[0016] Figure 3 is a side view of the negative phase gradient metasurface structure provided by the present application.

[0017] Figure 4 is a schematic diagram of the unit structure of the negative phase gradient metasurface structure provided by the present application.

[0018] Figure 5 is Figure 4 is a curve diagram of the reflection coefficient amplitude and phase of the negative phase gradient metasurface structure unit structure with frequency.

[0019] Figure 6 is a curve diagram of the reflection coefficient of the negative phase gradient metasurface structure provided by the present application with frequency.

[0020] Figure 7 is the E-plane pattern of the negative phase gradient metasurface structure provided by the present application at 12.5GHz.

[0021] Figure 8 is the E-plane pattern of the negative phase gradient metasurface structure provided by the present application at 13.5GHz.

[0022] Figure 9 is the E-plane pattern of the provided negative phase gradient metasurface structure at 15.5GHz.

[0023] 1-feeding structure, 2-negative phase gradient metasurface unit structure, 11-SMA connector, 12-waveguide, 21-first negative phase unit, 22-second negative phase unit, 23-third negative phase unit, 111-feeding probe, 121-housing cavity. DETAILED DESCRIPTION

[0024] Embodiments of the present application are described in detail below with reference to examples illustrated in the accompanying drawings, in which the same or similar components or components having the same or similar functions are denoted by the same or similar reference numerals throughout. The embodiments described below by reference to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application.

[0025] In the description of the application, it should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application. In addition, in the description of the application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0026] Referring to Figures 1 to 9 , the present application provides a negative phase gradient metasurface structure, comprising a feeding structure 1 and a negative phase gradient metasurface, the negative phase gradient metasurface unit structure 2 is embedded in the top of the feeding structure 1;

[0027] The negative phase gradient metasurface unit structure 2 comprises a first negative phase unit 21, a second negative phase unit 22 and a third negative phase unit 23, the first negative phase unit 21, the second negative phase unit 22, the third negative phase unit 23 are embedded in the top of the feeding structure 1 in turn, and the first negative phase unit 21, the second negative phase unit 22, the third negative phase unit 23 are located on the central axis of the wide side of the top of the feeding structure 1.

[0028] Further, the feeding structure 1 comprises an SMA connector 11 and a waveguide 12, the waveguide 12 is made of metal, the waveguide 12 has a containing cavity 121 inside, the waveguide 12 and the containing cavity 121 are cuboids, one end of the SMA connector 11 is embedded in the bottom of the waveguide 12, one end of a feeding probe 111 of the SMA connector 11 penetrates the bottom of the waveguide 12 and is located inside the containing cavity 121.

[0029] Further, the inside of the containing cavity 121 is filled with air.

[0030] Further, the thickness of the first dark surface unit 21, the thickness of the second dark surface unit 22 and the thickness of the third dark surface unit 23 are all the same as the distance from the top of the waveguide 12 to the inner top wall of the containing cavity 121.

[0031] Further, the distance between the second dark surface unit 22 and the first dark surface unit 21 is 14mm, and the distance between the second dark surface unit 22 and the third dark surface unit 23 is 14mm.

[0032] Further, the length of the waveguide 12 is 61mm, the width is 20mm, and the height is 7mm.

[0033] Further, the distance from the top of the waveguide 12 to the inner top wall of the containing cavity 121 is 1mm.

[0034] In the embodiment, the resonant frequency point of the waveguide 12 that can cover the dark surface phase gradient metasurface, the length of the feeding probe 111 of the SMA connector 11 will affect the S11 of the antenna, and the optimal value of the length of the feeding probe 111 is obtained by optimization. The shape of the first dark surface unit 21, the shape of the second dark surface unit 22 and the shape of the third dark surface unit 23 are all “I” type structures, and the outer radius of each of them is 6mm and the inner radius is 4.5mm. The air inside the waveguide 12 serves as the medium of the dark surface phase gradient metasurface, and the inner bottom wall of the containing cavity 121 serves as the metal ground of the dark surface phase gradient metasurface. The first dark surface unit 21, the second dark surface unit 22 and the third dark surface unit 23 form a weak phase gradient, so as to control the electromagnetic wave radiated from the waveguide 12. In the embodiment of the present application, the beam direction deflection angles of the antenna at different frequencies in the impedance bandwidth range are inconsistent, showing the characteristics of frequency scanning, which is similar to the characteristics of the traditional phase gradient metasurface.

[0035] Figure 5This is a graph showing the amplitude and phase of the cross-polarized reflection coefficient of the first negative surface element 21, the second negative surface element 22, and the third negative surface element 23 as a function of frequency in the frequency range of 11 GHz to 17 GHz. From the graph, we can see that the size of the open resonator ring, the inner radius, and the rotation direction of the element all change its reflection phase. Three different sets of values ​​were selected to obtain three negative surface element units with a phase difference of 120°. However, due to the presence of the reflector, the change in size has little effect on the reflection coefficient amplitude; the reflection coefficient amplitude of the three elements remains almost always greater than 0.7 within the impedance bandwidth.

[0036] Figure 6 The graph shows the reflection coefficient of the phase gradient metasurface structure on the negative side fed by the waveguide 12 provided by the present invention as a function of frequency in the frequency range of 11 GHz to 17 GHz. It can be seen that the impedance bandwidth of the antenna in this embodiment is 12.3 GHz to 14.2 GHz and 15.3 GHz to 16.0 GHz.

[0037] Figures 7 to 9 The figures show the E-plane radiation patterns and actual gains of the negative phase gradient metasurface structure provided by this invention at three frequencies: 12.5 GHz, 13.5 GHz, and 15.5 GHz. As can be seen from the figures, the angle of the maximum radiation direction of the E-plane radiation pattern differs at different frequencies, indicating a certain frequency scanning capability.

[0038] Based on the Babinski principle, this invention proposes a negative phase gradient metasurface structure complementary to conventional phase gradient metasurface structures. Specifically, the metallic portion of the original conventional unit cell is removed, and the original non-metallic portion is filled with metal. Utilizing the principle of slot radiation, a phase gradient metasurface is introduced to control the radiated electromagnetic waves. Simulation results show that the negative phase gradient metasurface exhibits electromagnetic properties similar to traditional phase gradient metasurfaces. With proper arraying, the directionality of the slot unit radiation can be improved. The above description is merely a preferred embodiment of the invention and should not be construed as limiting the scope of the invention. Those skilled in the art will understand that implementing all or part of the above embodiments and making equivalent variations according to the claims of this invention are still within the scope of the invention.

Claims

1. A negative phase gradient metasurface structure, characterized in that, comprising a feeding structure and a negative phase gradient metasurface unit structure, the negative phase gradient metasurface unit structure is embedded on the top of the feeding structure; the negative phase gradient metasurface unit structure comprises a first negative phase unit, a second negative phase unit and a third negative phase unit, the first negative phase unit, the second negative phase unit and the third negative phase unit are embedded on the top of the feeding structure in turn, and the first negative phase unit, the second negative phase unit and the third negative phase unit are located on the central axis of the wide side of the top of the feeding structure; the feeding structure comprises an SMA connector and a waveguide, the material of the waveguide is metal, the waveguide has a containing cavity inside, the waveguide and the containing cavity are both cuboids, one end of the SMA connector is embedded in the bottom of the waveguide, and one end of the feeding probe of the SMA connector penetrates through the bottom of the waveguide and is located inside the containing cavity; the thickness of the first negative phase unit, the thickness of the second negative phase unit and the thickness of the third negative phase unit are all the same as the distance from the top of the waveguide to the inner top wall of the containing cavity; the shape of the first negative phase unit, the shape of the second negative phase unit and the shape of the third negative phase unit are all "I" type structures, the outer radius of the three is 6mm, and the inner radius of the three is 4.5mm; the air inside the waveguide is used as the medium of the negative phase gradient metasurface, and the inner bottom wall of the containing cavity is used as the metal ground of the negative phase gradient metasurface.

2. The negative phase gradient metasurface structure of claim 1, characterized in that, the inside of the containing cavity is filled with air.

3. The negative phase gradient metasurface structure of claim 1, characterized in that, the distance between the second negative phase unit and the first negative phase unit is 14mm, and the distance between the second negative phase unit and the third negative phase unit is 14mm.

4. The negative phase gradient metasurface structure of claim 3, characterized in that, the length of the waveguide is 61mm, the width is 20mm, and the height is 7mm.

5. The negative phase gradient metasurface structure of claim 4, characterized in that, the distance from the top of the waveguide to the inner top wall of the containing cavity is 1mm.

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