Phase gradient metasurface antenna applied to long-distance transmission and implementation method

Abstract

The invention belongs to the technical field of antenna design, and particularly relates to a phase gradient metasurface antenna applied to long-distance transmission and an implementation method.The phase gradient metasurface antenna comprises a plurality of transmission phase gradient metasurface units arrayed in the phase gradient direction and a horn antenna, and the horn antenna is arranged at the tops of the transmission phase gradient metasurface units; the transmission phase gradient metasurface unit comprises four layers of metal units and three layers of dielectric substrates, and the metal units and the dielectric substrates are sequentially and alternately arranged from top to bottom. According to the horn antenna, after the metasurface transmission array is loaded, focusing of electromagnetic waves is achieved, the gain of the antenna is improved, for directional transmission, the forward directivity of the antenna is enhanced and converted into the power density in the forward direction, the transmission distance of the antenna is increased, and the transmission efficiency of the antenna is improved. And the Fries transmission formula is used to verify the increase of the antenna transmission distance. The metasurface antenna has the characteristics of high gain and long transmission distance.

Description

Technical Field

[0001] The present invention belongs to the technical field of antenna design, and in particular relates to a phase gradient metasurface antenna applied to long-distance transmission and an implementation method thereof. Background Art

[0002] In recent years, wireless transmission systems have developed rapidly. However, the antennas designed by existing antenna design methods have low gain and short transmission distance. This problem is particularly evident in many fields. First of all, from a technical perspective, the gain of existing antennas is usually low, which directly affects the signal propagation capability. For example, in wireless LAN equipment, due to poor antenna gain, the transmission distance is short and the cost is high. In addition, although microstrip antennas have the advantages of small size and light weight, their gain is low and the propagation distance is short, which also limits their application in wireless video transmission systems. Summary of the invention

[0003] In order to solve the technical problems that the antennas designed by the above-mentioned existing antenna design methods have low gain and short transmission distance, the present invention provides a phase gradient metasurface antenna for long-distance transmission and an implementation method thereof.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] A phase gradient metasurface antenna for long-distance transmission comprises a plurality of transmission phase gradient metasurface units arrayed along a phase gradient direction and a horn antenna, wherein the horn antenna is arranged on top of the transmission phase gradient metasurface unit, and the transmission phase gradient metasurface unit comprises four layers of metal units and three layers of dielectric substrates, which are alternately arranged as metal units and dielectric substrates from top to bottom.

[0006] The metal unit includes a metasurface metal square ring patch, an internal circular patch, a square groove and a separation groove. The metasurface metal square ring patch is arranged on the surface of a dielectric substrate, an internal circular patch is arranged on the metasurface metal square ring patch, a square groove is opened at the center of the internal circular patch, and separation grooves are respectively opened at both ends of the square groove.

[0007] The dielectric substrate adopts Rogers RO4003 substrate with a dielectric constant of 3.55; the period P of the dielectric substrate is 9.5 mm, and the height h is 3 mm.

[0008] The material of the metal unit is copper, with a thickness of 0.035 mm, the side length of the super-surface metal square ring patch is 0.2 mm; the width of the separation groove is 0.2 mm.

[0009] The outer radius of the inner circular patch is R1, the side length of the square groove is 0.4×R1, and the angle between the separation groove and one side of the metasurface metal square ring patch is 60°.

[0010] The array of the transmission phase gradient metasurface units is set to 18×18, and the focal length is 130 mm.

[0011] The phase difference distribution of each unit of the transmission phase gradient metasurface units arrayed along the phase gradient direction is:

[0012]

[0013] in: is the phase difference between the unit at the point (xp, np) and the origin, L is the focal length, and λ0 is the wavelength of the incident wave. A method for implementing a phase gradient metasurface antenna for long-distance transmission includes the following steps:

[0014] S1. By changing the inner circular patch radius of the transmission phase gradient metasurface unit, the characteristics of the transmission phase gradient metasurface unit are changed to obtain different transmission phase values. According to the array antenna theory, the beam is directed to a given direction by compensating the phase shift of each transmission phase gradient metasurface unit to obtain a phase compensation value.

[0015] S2. Determine the arrangement position and patch shape and size of each transmission phase gradient metasurface unit according to the phase value modulated by each transmission phase gradient metasurface unit obtained in S1;

[0016] S3, according to S2, a transmission phase gradient metasurface unit array is obtained, a horn antenna and an array combination are selected, the distance between the horn antenna and the transmission phase gradient metasurface unit array is adjusted, the S parameters and gain parameters of the metasurface antenna are obtained, and the results are compared with those without a transmission array;

[0017] S4. The formula for antenna transmission distance is obtained based on the Freese transmission formula. The antenna transmission distances before and after loading the transmission phase gradient metasurface unit are compared to verify the increase in its transmission distance.

[0018] The method for obtaining the modulation phase value of each transmission phase gradient metasurface unit in S1 is:

[0019] The phase gradient expression of the transmission phase gradient metasurface unit is:

[0020]

[0021] In the formula, is the phase gradient of the resonant unit group, n is the number of resonant units 6;

[0022]

[0023] in: is the phase difference between the unit at point (xp,np) and the origin, L is the focal length, and λ0 is the wavelength of the incident wave.

[0024] The method for obtaining the antenna transmission distance formula in S4 is:

[0025]

[0026] Where: R is the transmission distance between the transmitting antenna and the receiving antenna, P r is the received power, P t is the transmission power, G t is the gain of the transmitting antenna, G r is the gain of the receiving antenna, λ is the operating wavelength;

[0027] Compare the changes in the transmission distance of the antenna before and after loading the metamaterial. Assuming P r and P t Keep unchanged, G t1 is the gain after loading the metamaterial, G t2 is the gain without loading metamaterial, R1 is the transmission distance after loading metamaterial, and R2 is the transmission distance without loading metamaterial;

[0028] According to the Friis transmission formula, there exists

[0029] P r =P t +G t1 +G r ―20lg(R2)―20lg(f)

[0030] P r =P t +G t2 +G r ―20lg(R1)―20lg(f)

[0031] Where P r , P t , G r and f are the same in both cases, so after subtracting the two, we get

[0032]

[0033] G t1 and G t2 Substituting and simplifying, we get

[0034]

[0035] That is, after loading the metamaterial, the transmission distance increases to 1.778 times that of the unloaded one.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] After the horn antenna of the present invention is loaded with a metasurface transmission array, the focusing of electromagnetic waves is achieved, and the gain of the antenna is improved. For directional transmission, the forward directivity of the antenna is enhanced and converted into power density in the forward direction, thereby increasing the transmission distance of the antenna. This has important reference significance for the design of long-distance transmission antennas. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0039] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment of size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0040] Figure 1 It is a schematic structural diagram of a transmission phase gradient metasurface unit of the present invention;

[0041] Figure 2 It is a structural schematic diagram of the horn antenna of the present invention;

[0042] Figure 3 It is a simulation schematic diagram of a transmission phase gradient metasurface unit of the present invention;

[0043] Figure 4 It is a schematic diagram of the relationship between the inner circle radius and phase of the transmission phase gradient metasurface unit of the present invention;

[0044] Figure 5 It is a schematic diagram of the one-dimensional array structure of the transmission phase gradient metasurface unit of the present invention;

[0045] Figure 6 A simulated electric field diagram of a one-dimensional array of transmission phase gradient metasurface units of the present invention;

[0046] Figure 7 An array phase distribution diagram of the transmission phase gradient metasurface unit of the present invention;

[0047] Figure 8It is a schematic diagram of the actual patch arrangement distribution of the array surface of the transmission phase gradient metasurface unit of the present invention;

[0048] Fig. 9 Simulated gain diagram before loading the transmission phase gradient metasurface unit array for the horn antenna of the present invention;

[0049] Fig.10 A simulated gain diagram after the horn antenna of the present invention is loaded with a transmission phase gradient metasurface unit array;

[0050] Fig.11 A schematic diagram of the gain at different frequencies before the horn antenna of the present invention is loaded with a gradient metasurface unit array;

[0051] Fig.12 Schematic diagram of gain at different frequencies after the horn antenna of the present invention is loaded with a gradient metasurface unit array.

[0052] Among them: 1 is a transmission phase gradient metasurface unit, 101 is a metal unit, 1011 is a metasurface metal square ring patch, 1012 is an inner circular patch, 1013 is a square groove, 1014 is a separation groove, 102 is a dielectric substrate, and 2 is a horn antenna. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. These descriptions are only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0054] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0055] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0056] A phase gradient metasurface antenna for long-distance transmission, such as Figure 1-3As shown, it includes a plurality of transmission phase gradient metasurface units 1 and horn antennas 2 arrayed along the phase gradient direction, the horn antenna 2 is arranged on the top of the transmission phase gradient metasurface unit 1, and the transmission phase gradient metasurface unit 1 has four layers of metal units 101 and three layers of dielectric substrates 102, which are alternately arranged from top to bottom as metal units 101 and dielectric substrates 102. The metal unit 101 includes a metasurface metal square ring patch 1011, an inner circular patch 1012, a square groove 1013 and a separation groove 1014, the metasurface metal square ring patch 1011 is arranged on the surface of the dielectric substrate 102, the metasurface metal square ring patch 1011 is provided with an inner circular patch 1012, a square groove 1013 is opened at the center of the inner circular patch 1012, and separation grooves 1014 are opened at both ends of the square groove 1013.

[0057] Further, preferably, the dielectric substrate 102 adopts Rogers RO4003 substrate with a dielectric constant of 3.55; the period P of the dielectric substrate 102 is 9.5mm, and the height h is 3mm. The material of the metal unit 101 is copper, the thickness is 0.035mm, the side length of the metasurface metal square ring patch 1011 is 0.2mm; the width of the separation groove 1014 is 0.2mm. The outer circle radius of the inner circular patch 1012 is R1, the side length of the square groove 1013 is 0.4×R1, and the angle between the separation groove 1014 and one side of the metasurface metal square ring patch 1011 is 60°. The array of the transmission phase gradient metasurface unit 1 is set to 18×18, and the focal length is 130mm.

[0058] The transmission phase gradient metasurface unit 1 can realize the deflection of the propagation direction of the electromagnetic wave. Therefore, the deflection direction of any incident electromagnetic wave can be changed by controlling the reflection phase gradient or transmission phase gradient of the transmission phase gradient metasurface unit 1. In order to illustrate the deflection effect of the transmission phase gradient metasurface unit 1 on the electromagnetic wave, this embodiment will be demonstrated using a one-dimensional phase gradient array.

[0059] like Figure 4 As shown, the phase change of the transmission phase gradient metasurface unit 1 is achieved by changing the inner circle radius R1. Each transmission phase gradient metasurface unit 1 is formed into a one-dimensional phase gradient array to complete the one-dimensional phase gradient covering 360° phase change, thereby realizing the focusing function of the electromagnetic wave. Figure 5 As shown, the number of units in the one-dimensional metasurface array is 6 and the phase difference is 60°. Figure 6 The electric field distribution diagram of the one-dimensional phase gradient metasurface at 13 GHz is given. It can be seen that when a plane wave is incident vertically through the metasurface, the propagation direction of the electromagnetic wave is significantly deflected, and the refraction angle is 23.2°. The generalized Snell refraction law is:

[0060]

[0061] In the formula is the phase gradient of the reflection phase at the interface. i and θ r They represent the incident angle and the refraction angle respectively. i represents the refractive index of the incident medium, and λ represents the electromagnetic wavelength in free space. i For air, it is equal to 1, so Where n is the number of transmission phase gradient metasurface units 1, and p is the period of the unit. In this embodiment, the number of transmission phase gradient metasurface units 1 is 6, and the period side length is 9.5 mm. Substituting the result into θ r The results are similar to those of the simulation. The anomalous refraction phenomenon of the phase gradient metasurface is verified, and it is also proved that the designed unit has the ability to control the electromagnetic beam.

[0062] Adjust the phase difference distribution of the entire array, Figure 7 is the phase distribution diagram of the transmission metasurface unit array, where

[0063]

[0064] in is the phase difference between the unit at the point (xp, yp) and the origin, L is the focal length, and λ0 is the wavelength of the incident wave. In this embodiment, a phase gradient metasurface array is selected to be composed of 18×18 units with a focal length of 130 mm. Figure 8 Schematic diagram of the actual patch arrangement distribution of the phase gradient metasurface unit array in this embodiment.

[0065] like Fig. 9 , Fig.10 As shown in the figure, the antenna gain diagram is obtained by simulating the feed source of the horn antenna 2. At 13GHz, the gain is 12dB when the metasurface structure is not loaded, and the gain is 16.7dB after the metasurface is loaded. That is, the antenna gain is improved after the metasurface transmission array is loaded. Fig.11 , Fig.12 The gain changes before and after the metasurface structure is loaded show that the metasurface antenna has a maximum gain at a center frequency of about 13 GHz, and slightly decreases at other frequencies, indicating that the transmission phase gradient metasurface unit 1 array in this embodiment has a regulating effect on the accumulation of electromagnetic waves.

[0066] There is a formula to calculate the antenna transmission distance, namely the Friis transmission formula:

[0067]

[0068] Where R is the transmission distance between the transmitting antenna and the receiving antenna, P r is the received power, P t is the transmission power, Gt is the gain of the transmitting antenna, G r is the gain of the receiving antenna. λ is the working wavelength. This formula can be used to compare the change in the transmission distance of the antenna before and after loading the metamaterial. Assume that P r and P t Remain unchanged. t1 is the gain after loading the metamaterial, G t2 is the gain without metamaterial loading, R1 is the transmission distance after loading metamaterial, and R2 is the transmission distance without metamaterial loading. According to the Freese transmission formula (in logarithmic form), there is

[0069] P r =P t +G t1 +G r ―20lg(R2)―20lg(f)

[0070] P r =P t +G t2 +G r ―20lg(R1)―20lg(f)

[0071] Where P r , P t , G r and f are the same in both cases, so subtracting the two equations yields

[0072]

[0073] G t1 and G t2 Substituting in, we can simplify to

[0074]

[0075] That is, after loading the metamaterial, the transmission distance can be increased to about 1.778 times that of the unloaded one. This means that by increasing the gain of the antenna (achieved by loading the metamaterial), we can effectively extend the transmission distance of the antenna.

[0076] Only the preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention, and various changes should be included in the protection scope of the present invention.

Claims

1. A phase gradient metasurface antenna for long-distance transmission, characterized in that: The invention comprises a plurality of transmission phase gradient metasurface units (1) arrayed along a phase gradient direction and a horn antenna (2), wherein the horn antenna (2) is arranged on the top of the transmission phase gradient metasurface unit (1), and the transmission phase gradient metasurface unit (1) comprises four layers of metal units (101) and three layers of dielectric substrates (102), which are alternately arranged from top to bottom as metal units (101) and dielectric substrates (102).

2. The phase gradient metasurface antenna for long-distance transmission according to claim 1, characterized in that: The metal unit (101) comprises a metasurface metal square ring patch (1011), an inner circular patch (1012), a square groove (1013) and a separation groove (1014); the metasurface metal square ring patch (1011) is arranged on the surface of a dielectric substrate (102); the inner circular patch (1012) is arranged on the metasurface metal square ring patch (1011); a square groove (1013) is provided at the center of the inner circular patch (1012); and separation grooves (1014) are respectively provided at both ends of the square groove (1013).

3. The phase gradient metasurface antenna for long-distance transmission according to claim 2, characterized in that: The dielectric substrate (102) is a Rogers RO4003 substrate with a dielectric constant of 3.55; the period P of the dielectric substrate (102) is 9.5 mm, and the height h is 3 mm.

4. The phase gradient metasurface antenna for long-distance transmission according to claim 2, characterized in that: The metal unit (101) is made of copper and has a thickness of 0.035 mm. The side length of the super-surface metal square ring patch (1011) is 0.2 mm. The width of the separation groove (1014) is 0.2 mm.

5. The phase gradient metasurface antenna for long-distance transmission according to claim 2, characterized in that: The outer radius of the inner circular patch (1012) is R1, the side length of the square groove (1013) is 0.4×R1, and the angle between the separation groove (1014) and one side of the metasurface metal square ring patch (1011) is 60°.

6. The phase gradient metasurface antenna for long-distance transmission according to claim 1, characterized in that: The array of the transmission phase gradient metasurface units (1) is set to 18×18 units, and the focal length is 130 mm.

7. The phase gradient metasurface antenna for long-distance transmission according to claim 1, characterized in that: The phase difference distribution of each unit of the plurality of transmission phase gradient metasurface units (1) arrayed along the phase gradient direction is: in: is the phase difference between the unit at point (xp,np) and the origin, L is the focal length, and λ0 is the wavelength of the incident wave.

8. A method for realizing a phase gradient metasurface antenna for long-distance transmission according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, by changing the radius of the inner circular patch (1012) of the transmission phase gradient metasurface unit (1), the characteristics of the transmission phase gradient metasurface unit (1) are changed to obtain different transmission phase values, and according to the array antenna theory, the beam is directed to a given direction by compensating the phase shift of each transmission phase gradient metasurface unit (1) to obtain a phase compensation value; S2, determining the arrangement position and patch shape and size of each transmission phase gradient metasurface unit (1) according to the phase value modulated by each transmission phase gradient metasurface unit (1) obtained in S1; S3, obtaining a transmission phase gradient metasurface unit (1) array according to S2, selecting a horn antenna (2) and the array combination, adjusting the distance between the horn antenna (2) and the transmission phase gradient metasurface unit (1) array, obtaining the S parameters and gain parameters of the metasurface antenna, and comparing them with the array without transmission; S4. The formula for the antenna transmission distance is obtained according to the Friis transmission formula, and the antenna transmission distances before and after the transmission phase gradient metasurface unit (1) is loaded are compared to verify the increase in the transmission distance.

9. The method for realizing a phase gradient metasurface antenna for long-distance transmission according to claim 8, characterized in that: The method for obtaining the modulation phase value of each transmission phase gradient metasurface unit (1) in S1 is: The phase gradient expression of the transmission phase gradient metasurface unit (1) is: In the formula, is the phase gradient of the resonant unit group, n is the number of resonant units 6; in: is the phase difference between the unit at point (xp,np) and the origin, L is the focal length, and λ0 is the wavelength of the incident wave.

10. The method for realizing a phase gradient metasurface antenna for long-distance transmission according to claim 8, characterized in that: The method for obtaining the antenna transmission distance formula in S4 is: Where: R is the transmission distance between the transmitting antenna and the receiving antenna, P r is the received power, P t is the transmission power, G t is the gain of the transmitting antenna, G r is the gain of the receiving antenna, λ is the operating wavelength; Compare the changes in the transmission distance of the antenna before and after loading the metamaterial. Assuming P r and P t Keep unchanged, G t1 is the gain after loading the metamaterial, G t2 is the gain without loading metamaterial, R1 is the transmission distance after loading metamaterial, and R2 is the transmission distance without loading metamaterial; According to the Friis transmission formula, there exists P r =P t +G t1 +G r ―20lg(R2)―20lg(f) P r =P t +G t2 +G r ―20lg(R1)―20lg(f) Where P r , P t , G r and f are the same in both cases, so after subtracting the two, we get G t1 and G t2 Substituting and simplifying, we get That is, after loading the metamaterial, the transmission distance increases to 1.778 times that of the unloaded one.

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