An orbital angular momentum antenna using mxene and graphene

Abstract

The application discloses an orbital angular momentum antenna using MXene material and graphene, which comprises an MXene patch layer, an upper-layer polyimide (PI) dielectric substrate, a graphene patch layer, a lower-layer PI dielectric substrate and a metal ground layer. The antenna comprises, from top to bottom, the MXene patch layer, the upper-layer PI dielectric substrate, the graphene patch layer, the lower-layer PI dielectric substrate and the metal ground layer. The MXene patch layer is an 8-MXene-patch ring-shaped layer uniformly distributed on the upper-layer PI dielectric substrate, the upper-layer PI dielectric substrate is the second layer, the graphene patch layer is an 8-graphene-patch ring-shaped layer uniformly distributed on the lower-layer PI dielectric substrate, the lower-layer PI dielectric substrate is the fourth layer, and the metal ground layer is the fifth layer. The antenna realizes reconfiguration of the working frequency band by adjusting the chemical potential of graphene, and can generate stable orbital angular momentum vortex waves with mode numbers l=0, 0.5, 1, 1.5, 2, 2.5 and 3 only by adjusting the feed phase difference.

Description

TECHNICAL FIELD

[0001] The application relates to an orbital angular momentum antenna using an MXene patch and a graphene patch and belongs to the technical field of orbital angular momentum antennas. BACKGROUND

[0002] With the rapid development of mobile communication technology and the wide popularity of mobile terminal equipment, the shortage of spectrum resources has become an important problem that has plagued people in the field of wireless communication. In order to solve this problem, it is urgent to find a new generation of wireless mobile communication technology that is more efficient and more intelligent. Developing new spectrum resources (such as adopting millimeter wave technology) or improving spectrum utilization (such as large-scale array antenna multiple-in multiple-out technology in the 5G era) are two major methods to improve system capacity. The development of mobile communication technology is closely related to the generation of revolutionary technology, and how to efficiently and high-quality transmit information has been a difficult problem that people have been trying to solve for a long time.

[0003] In recent years, orbital angular momentum (OAM) has attracted much attention due to its ability to effectively expand channel capacity and improve spectrum efficiency. OAM is also known as a vortex electromagnetic wave because of its spiral wave front phase distribution. OAM has a high degree of freedom and good anti-interference ability, and theoretically has an infinite number of different modes, and each mode is orthogonal and does not interfere with each other. This characteristic can be used to transmit multiple signals on the same carrier frequency. Therefore, the multiplexing communication technology based on orbital angular momentum can greatly improve the spectrum utilization, and the discovery of orbital angular momentum also provides a new way to solve the problem of spectrum resource shortage in the future.

[0004] Graphene is a two-dimensional material with special properties. Because of its high restriction, low loss, good flexibility and adjustability, it can well replace precious metals in the terahertz and far infrared regions. At the same time, graphene also has the excellent characteristic of adjustable electrical conductivity, which provides a theoretical basis for designing reconfigurable applications in the terahertz range. MXene material is a new type of two-dimensional transition metal carbon / nitride material, which has high conductivity. At the same time, it is popular because of its advantages of foldability, plasticity and easy processing into various complex shapes. This material has great application prospects in the field of mobile communication. SUMMARY

[0005] The application aims at the defects and deficiencies of the prior art, and provides an antenna capable of generating orbital angular momentum. The antenna realizes reconfiguration of the antenna operating frequency band by adjusting the chemical potential of graphene, and can generate stable orbital angular momentum vortex waves with mode numbers l=0, 0.5, 1, 1.5, 2, 2.5 and 3 by adjusting the feed phase difference.

[0006] The technical scheme adopted by the present application to solve its technical problems is: an orbital angular momentum antenna using MXene and graphene, comprising an MXene patch layer, an upper layer PI dielectric substrate, a graphene patch layer, a lower layer PI dielectric substrate and a metal ground layer. The first layer from top to bottom of the antenna is the MXene patch layer, the MXene patch layer is 8 MXene patches, the MXene patches are uniformly distributed in a ring shape on the upper layer PI dielectric substrate, the second layer is the upper layer PI dielectric substrate, the third layer is the graphene patch layer, the graphene patch layer is 8 graphene patches, the graphene patches are uniformly distributed in a ring shape on the lower layer PI dielectric substrate, the fourth layer is the lower layer PI dielectric substrate, and the fifth layer is the metal ground layer. The antenna adopts an L-shaped feeding structure for feeding, the L-shaped feeding structure is arranged below each graphene patch, the L-shaped feeding structure penetrates the lower layer PI dielectric substrate and the metal ground layer, and each feeding structure is provided with a feeding port below.

[0007] Further, the MXene patch is circular, the material is Ti3C2 MXene, and the radius is 36 μm.

[0008] Further, the distance from the center of the MXene patch to the center of the upper layer PI dielectric substrate is 120 μm.

[0009] Further, the upper layer PI dielectric substrate is circular, the material is PI, the radius is 160 μm, and the thickness is 15 μm.

[0010] Further, the graphene temperature of the graphene patch is 300 K, the chemical potential μ c = 1 eV, and the relaxation time is 1 ps.

[0011] Further, the graphene patch is circular, and the radius is 40 μm.

[0012] Further, the distance from the center of the graphene patch to the center of the lower layer PI dielectric substrate is 120 μm.

[0013] Further, the L-shaped feeding structure has a bottom surface radius of 2 μm, a height of 33 μm, and a length of 40 μm.

[0014] Further, the 8 feeding ports are circular, each has a radius of 2 μm, and the distance from the center of each feeding port to the center of the metal ground layer is 121.66 μm.

[0015] Further, the lower layer PI dielectric substrate is circular, the material is PI, the radius is 250 μm, and the thickness is 15 μm.

[0016] Further, the antenna adopts a coaxial feeding mode, and when 8 feeding ports are fed with a continuous phase difference of 0°, 22.5°, 45°, 67.5°, 90°, 112.5°, 135° respectively, vortex waves with mode numbers l=0, 0.5, 1, 1.5, 2, 2.5, 3 can be generated.

[0017] Beneficial effects:

[0018] 1. The graphene chemical potential is adjusted to realize the reconfigurability of the antenna operating frequency band, and the designed antenna mode changes easily and has good vortex wave characteristics.

[0019] 2. The antenna realizes the reconfigurability of the antenna operating frequency band by adjusting the graphene chemical potential, and only needs to adjust the feeding phase difference to generate stable orbital angular momentum vortex waves with mode numbers l=0, 0.5, 1, 1.5, 2, 2.5 and 3. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a top view of the antenna of the application.

[0021] Figure 2 is a schematic diagram of a unit structure of the antenna of the application.

[0022] Figure 3 is a schematic diagram of a feeding position of the antenna of the application.

[0023] Figure 4 is a schematic diagram of a graphene layer of the antenna of the application.

[0024] Figure 5 is a front view of the antenna of the application.

[0025] Figure 6 is a schematic diagram of an L-shaped feeding structure.

[0026] Figure 7 is an OAM antenna S parameter diagram.

[0027] Figure 8 is a vortex wave phase diagram of different modes at 1.5THz, wherein (a) is a vortex wave phase diagram when the mode number is 0; (b) is a vortex wave phase diagram when the mode number is 0.5; (c) is a vortex wave phase diagram when the mode number is 1; (d) is a vortex wave phase diagram when the mode number is 1.5; (e) is a vortex wave phase diagram when the mode number is 2; (f) is a vortex wave phase diagram when the mode number is 2.5; (g) is a vortex wave phase diagram when the mode number is 3.

[0028] Figure 9 is a far-field direction gain change diagram of the antenna under different modes.

[0029] Figure 10The S of the antenna at different chemical potentials of graphene 11 Parameter diagram, where (a) is the S of the antenna at the graphene chemical potential of 0-1 eV. 11 (a) is the parameter diagram; (b) shows the S-axis of the antenna at a graphene chemical potential of 1.2-2 eV. 11 Parameter diagram. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0031] like Figures 1 to 6 As shown, an embodiment of the present invention is an orbital angular momentum antenna using MXene and graphene. The structure comprises an MXene patch layer, an upper PI dielectric substrate, a graphene patch layer, an L-shaped feed structure, a lower PI dielectric substrate, a metal ground layer, and a feed port. The MXene patch is circular, made of Ti3C2 MXene, with a radius of r1 = 36 μm, and is placed on the upper surface of the upper PI dielectric substrate. The distance from the center of the patch to the center of the upper PI dielectric substrate is r2 = 120 μm. The upper PI dielectric substrate is placed between the MXene patch layer and the graphene patch layer, is circular in shape, made of PI, and has a radius and thickness of r3 = 160 μm and h1 = 15 μm, respectively. The graphene patch is at a temperature of 300 K and a chemical potential of μ. c =1eV, relaxation time is 1ps, shape is circular with radius r4 = 40μm, placed on the upper surface of the lower PI dielectric substrate, distance from the center of the patch to the center of the lower PI dielectric substrate is r5 = 120μm; the lower PI dielectric substrate is placed between the graphene patch and the ground metal layer, shape is circular with radius and thickness r6 = 250μm and h2 = 15μm respectively; the ground metal layer has the same radius as the lower PI dielectric substrate, thickness h3 = 20μm, and is placed on the lower surface of the lower PI dielectric substrate; the bottom radius of the L-shaped feed structure is L1 = 2μm, and the height is L 2＝ The antenna is 33 μm long and L3 = 40 μm long, penetrating the lower PI dielectric substrate and the grounding metal layer. Its eight feed ports are all circular with a radius of 2 μm, and the distance from the center of the port to the center of the structure is r7 = 121.66 μm, located on an L-shaped feed structure. After the structural design was completed, coaxial feeding was used to feed the feed ports with different phases to excite vortex waves: feeding the eight feed ports with continuous phase differences of 0°, 22.5°, 45°, 67.5°, 90°, 112.5°, and 135° respectively can generate vortex waves with mode numbers l = 0, 0.5, 1, 1.5, 2, 2.5, and 3.

[0032] To observe the antenna's performance, the input impedance was set to 50Ω for simulation. Because the designed orbital angular momentum antenna structure is highly symmetrical, the return loss and insertion loss of the eight array elements are identical; therefore, only the feed simulation of port 1 is required. The simulation yielded S... 11 Parameters and S 21 S 31 Equal insertion loss such as Figure 7 As shown in the figure, the antenna's -10dB bandwidth is located in the 1.28-1.58THz frequency range, with an absolute bandwidth of 0.3THz and a relative bandwidth of approximately 21%. 11 The value reached -25.4dB, and since the antenna is a uniform ring array, S 21 With S 81 S 31 With S 71 S 41 With S 61 The curves tend to change in a similar direction.

[0033] The wavefront phase distribution and mode number are the two most important indicators for generating orbital angular momentum vortex waves in this invention. The far-field phase distribution diagram of the antenna designed in this invention, obtained through simulation, is shown below. Figure 8 As shown. Figure 8 (a) in the figure is the phase diagram generated by feeding eight feed ports with a continuous phase difference of 0°. It can be clearly seen in the figure that a spiral phase forms a ring and the phase of the ring changes by 360°, which corresponds to a vortex wave with mode number l = 0. Figure 8 (b) to (g) correspond to vortex waves with mode numbers of 0.5, 1, 1.5, 2, 2.5, and 3, respectively. The OAM wavefront phase distribution of the integer-order modes 0, 1, 2, and 3 exhibits a clear and uniform spiral distribution, with each curve showing a uniform shape, indicating that the vortex beamform generated by this array antenna is excellent. Furthermore, for the fractional-order modes, due to the existence of incomplete modes, the wavefront phase diagram exhibits an asymmetrical spiral structure, which is consistent with the fractional-order phase variation. Figure 9 The graph shows the far-field gain variation of the antenna in different modes when operating at 1.5 THz. It can be seen from the graph that the antenna achieves the highest gain in mode 1. In summary, the antenna designed in this invention can generate stable and adjustable multimode vortex waves.

[0034] This invention alters the chemical potential of graphene by applying a bias magnetic or electric field to both ends of the graphene. Changes in the graphene's chemical potential affect antenna performance; therefore, adjusting the graphene's chemical potential improves antenna performance. Simulations yield the S... 11 The parameters change with chemical potential as follows Figure 10 As shown in (a)(b), when μ c When varying within the range of 0.6–2.0 eV, as μc With the increase of the chemical potential of graphene, the working bandwidth of the antenna gradually shifts to high frequency, but the absolute bandwidth of the antenna is about 0.3 THz, which shows that using graphene as the radiating patch of the antenna can effectively regulate the working frequency band of the antenna. Therefore, the performance of the orbital angular momentum antenna designed in the application can be optimized by adjusting the chemical potential of graphene.

[0035] The above examples are used to explain and illustrate the application, but not to limit the application, and any modification and change made to the application within the spirit and protection scope of the claims of the application shall fall into the protection scope of the application.

Claims

1. An orbital angular momentum antenna using MXene and graphene, characterized in that: The antenna comprises a MXene patch layer, an upper PI dielectric substrate, a graphene patch layer, a lower PI dielectric substrate and a metal ground layer, the first layer from top to bottom is the MXene patch layer, the MXene patch layer is 8 MXene patches, the MXene patches are uniformly distributed in a ring shape on the upper PI dielectric substrate, the second layer is the upper PI dielectric substrate, the third layer is the graphene patch layer, the graphene patch layer is 8 graphene patches, the graphene patches are uniformly distributed in a ring shape on the lower PI dielectric substrate, the fourth layer is the lower PI dielectric substrate, and the fifth layer is the metal ground layer, the antenna adopts an L-shaped feeding structure for feeding, the L-shaped feeding structure is arranged below each graphene patch, the L-shaped feeding structure penetrates the lower PI dielectric substrate and the metal ground layer, one feeding port is arranged below each feeding structure, and the antenna adopts a coaxial feeding mode, when 8 feeding ports are fed with a continuous phase difference of 0°, 22.5°, 45°, 67.5°, 90°, 112.5°, 135°, vortex waves with mode numbers l=0, 0.5, 1, 1.5, 2, 2.5, 3 can be generated.

2. The orbital angular momentum antenna using MXene and graphene according to claim 1, wherein, The MXene patch is circular, and the radius is 36μm.

3. The orbital angular momentum antenna using MXene and graphene according to claim 1, wherein, The distance from the center of the MXene patch to the center of the upper PI dielectric substrate is 120μm.

4. The orbital angular momentum antenna using MXene and graphene according to claim 1, wherein, The upper PI dielectric substrate is circular, the radius is 160μm, and the thickness is 15μm.

5. The orbital angular momentum antenna using MXene and graphene according to claim 1, wherein, The graphene patch is circular, and the radius is 40μm.

6. The orbital angular momentum antenna using MXene and graphene according to claim 1, wherein, The distance from the center of the graphene patch to the center of the lower PI dielectric substrate is 120μm.

7. The orbital angular momentum antenna using MXene and graphene according to claim 1, wherein, The L-shaped feeding structure has a bottom surface radius of 2μm, a height of 33μm, and a length of 40μm.

8. The orbital angular momentum antenna using MXene and graphene according to claim 1, wherein, The 8 feeding ports are all circular, the radius is 2μm, and the distance from the center of each feeding port to the center of the metal patch is 121.66μm.

9. The orbital angular momentum antenna using MXene and graphene according to claim 1, wherein, The lower PI dielectric substrate is circular, the radius is 250μm, and the thickness is 15μm.

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