Millimeter wave flexible transparent high-gain circularly polarized antenna based on AMC and preparation method thereof

Abstract

The application belongs to the technical field of antennas and preparation, and relates to a millimeter wave circularly polarized antenna, in particular to a millimeter wave flexible transparent high-gain circularly polarized antenna based on AMC and a preparation method thereof. The antenna comprises a radiator, a first dielectric substrate, a second dielectric substrate and an AMC super surface unit. The 2*2 periodically arranged AMC super surface units are arranged on the upper surface of the second dielectric substrate, the first dielectric substrate is arranged at the position 0.5 mm above the center position of the second dielectric substrate, and the radiator is fixed on the first dielectric substrate. The antenna can effectively reduce the overall profile size, improve the gain and the performance, and the resonant elliptical ring and the fan-shaped slot of the central symmetrical structure make the antenna have the circular polarization characteristic.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of antennas and preparation, and relates to a millimeter wave circularly polarized antenna, in particular to a millimeter wave flexible transparent high-gain circularly polarized antenna based on AMC and a preparation method thereof, which can be used in a 5G relay base station. BACKGROUND

[0002] In recent years, with the rapid development of the fifth generation mobile communication technology (5G), people's demand for high-speed and low-latency information transmission is increasing, which brings higher and higher requirements for the indicators of related antennas. As one of the main frequency bands of 5G communication, millimeter wave is obviously different from the previous generation of communication systems, and thus it and the terminal antenna that transmits and receives it together constitute an important aspect of the key technology of 5G communication, that is, a new millimeter wave antenna technology. As a bridge and link for information interaction with the external free space, the innovation of the antenna technology is an extremely important part of the evolution blueprint of 5G communication technology, and the millimeter wave technology is another innovation of 5G communication different from the previous generation of communication technology.

[0003] The polarization of electromagnetic wave is generally described by the motion trajectory of the end of the vector electric field. According to the shape formed by the trajectory of the end of the vector electric field over time, the polarization of electromagnetic wave is divided into linear polarization, circular polarization and elliptical polarization, and according to the direction of the motion of the end of the vector electric field, the circular (elliptical) polarization can be further divided into left-handed circular (elliptical) polarization and right-handed circular (elliptical) polarization. The generation of circularly polarized wave is through exciting a radiating antenna to generate two linearly polarized waves that are mutually orthogonal, have the same amplitude and a phase difference of 90°.

[0004] Due to its strong anti-interference ability, better mobility and multipath suppression ability, the circularly polarized (CP) antenna is applied on more and more devices, and in some application scenarios, such as airborne antennas, vehicle-mounted antennas, indoor antennas and the like, a wideband and low-profile antenna is one of the trends of the development of wireless communication technology, therefore, it is very important to improve the bandwidth of the circularly polarized antenna and realize high gain and low profile characteristics. In order to explore the characteristic of in-phase reflection, a periodic patch surface structure without through holes, that is, an artificial magnetic conductor (AMC), is proposed, in which the phase of the reflected wave is equal to the phase of the incident wave within a certain frequency range. The AMC reflector can be used to reduce the height of the antenna, and the AMC reflector has great potential in the application of antenna miniaturization, therefore, it is of great value and significance to research and design a new AMC structure and apply it to the antenna to realize the low profile characteristic of the antenna. SUMMARY

[0005] The application aims to solve the problems in the prior art and provides a millimeter wave flexible transparent high-gain circularly polarized antenna based on AMC and a preparation method thereof.

[0006] To achieve the above object, the AMC-based millimeter wave flexible transparent high-gain circularly polarized antenna comprises a radiator, a first dielectric substrate, a second dielectric substrate and an AMC metasurface unit; the second dielectric substrate is provided with 2x2 periodically arranged AMC metasurface units on the upper surface, the first dielectric substrate is arranged at a position 0.5 mm above the center of the second dielectric substrate, and the radiator is fixed on the first dielectric substrate.

[0007] As a further technical solution of the present application, the radiator comprises a square ring patch, a resonant elliptical ring and a microstrip feed line, two resonant elliptical rings are symmetrically arranged on the symmetry axis of the square ring patch, the outer circle of the resonant elliptical ring is tangent to the inner edge of the square ring patch, two diagonal positions of the resonant elliptical ring on the square ring patch are respectively cut with 90° sector slots, the microstrip feed line is arranged on the lower surface of the first dielectric substrate, and the microstrip feed line is parallel to the long axis of the resonant elliptical ring.

[0008] As a further technical solution of the present application, the AMC metasurface unit adopts a square patch structure with two diagonal cut corners.

[0009] As a further technical solution of the present application, the second dielectric substrate is composed of four layers of structures arranged from top to bottom, i.e., a first PET layer, a PVC layer, an ITO layer and a second PET layer.

[0010] As a further technical solution of the present application, the radiator is made of ITO material with a thickness of 10 um and an electrical conductivity of 20000 S / m.

[0011] As a further technical solution of the present application, the microstrip feed line adopts a 50Ω rectangular microstrip feed line with a length of 2.75 mm and a width of 0.37 mm, which is used to realize the circular polarization characteristics of the antenna.

[0012] As a further technical solution of the present application, the outer edge length of the square ring patch is 5 mm, the inner edge length is 3.4 mm, the outer circle axis ratio of the resonant elliptical ring is 1.25, the outer circle long axis is 1.2 mm, the inner circle axis ratio is 1.43, the inner circle long axis is 0.7 mm, and the radius of the sector slot is 0.7 mm.

[0013] As a further technical solution of the present application, the side length of the AMC metasurface unit is 5.25 mm, the cut corner is an isosceles right triangle, the hypotenuse length is 2 mm, and the interval between the two connected AMC metasurface units is 1 mm.

[0014] As a further technical scheme of the present application, the dielectric constant and thickness of the first and second dielectric substrates are different, the first dielectric substrate is made of PET material with a thickness of 0.125 mm, the relative dielectric constant is 3.2, and the loss tangent is 0.003; the PVC layer of the second dielectric substrate is made of PVC material with a thickness of 1.5 mm, the relative dielectric constant is 2.7, and the loss tangent is 0.007; the ITO layer of the second dielectric substrate is made of ITO material with a thickness of 1.5 mm, the conductivity is 20000 S / m; and the PET layer of the second dielectric substrate is made of PET material with a thickness of 0.125 mm, the relative dielectric constant is 3.2, and the loss tangent is 0.003.

[0015] The specific process of preparing the AMC-based millimeter wave flexible transparent high-gain circularly polarized antenna is as follows:

[0016] (1) a first dielectric substrate is made of PET material with a thickness of 0.125 mm, and four layers of a second dielectric substrate are made of PET material, PVC material and ITO material respectively and are stacked in order to form the second dielectric substrate;

[0017] (2) an AMC metasurface unit 4 is obtained by cutting the corners of the square patch, and four AMC metasurface units are arranged periodically on the second dielectric substrate;

[0018] (3) a radiator is made of ITO material, and the radiator is placed on the first dielectric substrate;

[0019] (4) the first dielectric substrate is placed above the second dielectric substrate at a distance of 0.5 mm, and the antenna is completed.

[0020] Compared with the prior art, the present application has the following advantages:

[0021] 1. The patch structure and dielectric substrate used in the present application are made of PET or PVC materials, which are flexible and bendable;

[0022] 2. The radiator designed in the present application has an outer side length of 5*5 mm and can work in the 5G millimeter wave band;

[0023] 3. The present application designs 2*2 AMC metasurface units on the second dielectric substrate, and in a certain frequency range, the phase of the reflected wave is equal to the phase of the incident wave, which can effectively reduce the overall profile size of the antenna, improve the gain, and improve the performance;

[0024] 4. The present application designs a center-symmetric structure of resonant elliptical ring and fan-shaped slot, so that the antenna has circular polarization characteristics. BRIEF DESCRIPTION OF DRAWINGS

[0025] Fig. 1This is a schematic diagram of the main structure of the millimeter-wave flexible transparent high-gain circularly polarized antenna based on AMC described in this invention.

[0026] Fig. 2 This is a schematic diagram of the front view structure of the radiator described in this invention.

[0027] Fig. 3 This is a schematic diagram of the rear view structure of the radiator described in this invention.

[0028] Fig. 4 This is the S11 performance curve of the millimeter-wave flexible transparent high-gain circularly polarized antenna based on AMC described in this invention.

[0029] Fig. 5 This is an AR performance curve of the millimeter-wave flexible transparent high-gain circularly polarized antenna based on AMC described in this invention.

[0030] Fig. 6 This is a graph showing the maximum actual gain of the millimeter-wave flexible transparent high-gain circularly polarized antenna based on AMC as described in this invention. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0032] Example 1:

[0033] like Figs. 1-3 As shown, the millimeter-wave flexible transparent high-gain circularly polarized antenna based on AMC provided in this embodiment includes a radiator 1, a first dielectric substrate 2, a second dielectric substrate 3, and AMC metasurface units 4; the upper surface of the second dielectric substrate 3 is provided with 2×2 periodically arranged AMC metasurface units 4, which reduces the electromagnetic wave reflection phase to 0, further reducing the antenna profile; the first dielectric substrate 2 is located 0.5mm above the center position of the second dielectric substrate 3, and the radiator 1 is fixed on the first dielectric substrate 2;

[0034] The radiator 1 is made of ITO material with a thickness of 10 um and an electrical conductivity of 20000 S / m, and includes a square ring patch 101, a resonant elliptical ring 102 and a microstrip feed line 103. Two resonant elliptical rings 102 are symmetrically arranged on the symmetry axis of the square ring patch 101, the outer circle of the resonant elliptical ring 102 is tangent to the inner edge of the square ring patch 101, and the square ring patch 101 is cut at two opposite corners of the symmetry axis of the resonant elliptical ring 102 to form a 90° sector slot. The microstrip feed line 103 is arranged on the lower surface of the first dielectric substrate 2, and the microstrip feed line 103 is parallel to the long axis of the resonant elliptical ring 102. The outer edge length of the square ring patch 101 is 5 mm, the inner edge length is 3.4 mm, the outer circle axis ratio of the resonant elliptical ring 102 is 1.25, the outer circle long axis is 1.2 mm, the inner circle axis ratio is 1.43, the inner circle long axis is 0.7 mm, and the radius of the sector slot is 0.7 mm. The microstrip feed line 103 is a 50Ω rectangular microstrip feed line, and the length of the microstrip feed line 103 is 2.75 mm and the width is 0.37 mm. The structure of the radiator 1 can effectively improve the antenna axial ratio and realize circular polarization characteristics.

[0035] The AMC metasurface unit 4 adopts a square patch structure with two opposite corners having a cut angle; the side length of the AMC metasurface unit 4 is 5.25 mm, and the cut angle is an isosceles right triangle with an oblique side length of 2 mm; and the interval between the two connected AMC metasurface units 4 is 1 mm.

[0036] The second dielectric substrate 3 is composed of four layers of structures from top to bottom, i.e., a first PET layer 301, a PVC layer 302, an ITO layer 303 and a second PET layer 304. The dielectric constant and thickness of the first dielectric substrate and the second dielectric substrate are different. The first dielectric substrate 2 is made of PET material with a thickness of 0.125 mm, a relative dielectric constant of 3.2 and a loss tangent of 0.003. The PVC layer 302 of the second dielectric substrate 3 is made of PVC material with a thickness of 1.5 mm, a relative dielectric constant of 2.7 and a loss tangent of 0.007. The ITO layer 303 of the second dielectric substrate 3 is made of ITO material with a thickness of 1.5 mm and an electrical conductivity of 20000 S / m. The PET layers 301 and 304 of the second dielectric substrate 3 are made of PET material with a thickness of 0.125 mm, a relative dielectric constant of 3.2 and a loss tangent of 0.003.

[0037] Embodiment 2

[0038] In this embodiment, the millimeter wave flexible transparent high-gain circularly polarized antenna based on AMC in embodiment 1 is prepared, and the specific process is as follows:

[0039] (1) The first dielectric substrate 2 is made of PET material with a thickness of 0.125 mm, and the four-layer structure of the second dielectric substrate 3 is made of PET material, PVC material and ITO material respectively, and is stacked in order to make the second dielectric substrate 3;

[0040] (2) The AMC metasurface unit 4 is obtained by cutting the corners of the square patch at the diagonal, and the four AMC metasurface units 4 are periodically arranged on the second dielectric substrate 3;

[0041] (3) The radiator 1 is made of ITO material, and is placed on the first dielectric substrate 1;

[0042] (4) The first dielectric substrate 1 is placed above the second dielectric substrate 2 at a distance of 0.5 mm, the preparation of the antenna is completed, and the performance test of the prepared antenna is carried out, and the specific results are shown in Figs. 4-6 .

Claims

1. An AMC-based millimeter-wave flexible transparent high-gain circularly polarized antenna, characterized in that, The application relates to an antenna, which comprises a radiator, a first dielectric substrate, a second dielectric substrate and an AMC super surface unit; the second dielectric substrate is provided with 2*2 periodically arranged AMC super surface units on the upper surface, the first dielectric substrate is arranged at a position 0.5 mm above the center of the second dielectric substrate, and the radiator is fixed on the first dielectric substrate; the radiator comprises a square ring-shaped patch, a resonant elliptical ring and a microstrip feed line, two resonant elliptical rings are symmetrically arranged on the symmetry axis of the square ring-shaped patch, the outer circle of the resonant elliptical ring is tangent to the inner edge of the square ring-shaped patch, two diagonal positions of the symmetry axis of the resonant elliptical ring are respectively cut to form 90-degree sector slots on the square ring-shaped patch, the microstrip feed line is arranged on the lower surface of the first dielectric substrate, and the microstrip feed line is parallel to the long axis of the resonant elliptical ring; the AMC super surface unit adopts a square patch structure with two diagonal cut corners; the second dielectric substrate comprises four layers of structures from top to bottom, namely a first PET layer, a PVC layer, an ITO layer and a second PET layer; the thickness of the radiator is 10 um, and the conductivity is 20000 S / m; the microstrip feed line adopts a 50 omega rectangular microstrip feed line, the length of the microstrip feed line is 2.75 mm, and the width is 0.37 mm; the outer edge length of the square ring-shaped patch is 5 mm, the inner edge length is 3.4 mm, the outer circle axis ratio of the resonant elliptical ring is 1.25, the outer circle long axis is 1.2 mm, the inner circle axis ratio is 1.43, the inner circle long axis is 0.7 mm, and the radius of the sector slot is 0.7 mm.

2. The AMC-based millimeter-wave flexible transparent high-gain circularly polarized antenna of claim 1, wherein, The side length of the AMC super surface unit is 5.25 mm, the cut corner is an isosceles right triangle, the hypotenuse length is 2 mm, and the interval between the two connected AMC super surface units is 1 mm.

3. A method of fabricating an AMC-based millimeter-wave flexible transparent high-gain circularly polarized antenna according to any one of claims 1-2, characterized in that, The specific process is as follows: (1) a first dielectric substrate is prepared by selecting PET material with a thickness of 0.125 mm, four layers of structures of a second dielectric substrate are prepared by selecting PET material, PVC material and ITO material respectively, and the second dielectric substrate is prepared by stacking the four layers of structures in sequence; (2) the AMC super surface unit is obtained by cutting the corners of the square patch, and the four AMC super surface units are periodically arranged on the second dielectric substrate; (3) the radiator is prepared by using ITO material, and the radiator is arranged on the first dielectric substrate; (4) the first dielectric substrate is arranged above the second dielectric substrate at a position 0.5 mm away from the second dielectric substrate, and the antenna is prepared.

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