Three-dimensional graphene antenna and preparation method thereof

Abstract

A three-dimensional graphene antenna includes a three-dimensional graphene radiation layer, a dielectric substrate, a metal layer and a feeder line. The three-dimensional graphene radiation layer is made from porous three-dimensional graphene. A preparation method of the porous three-dimensional graphene includes steps of preparing pressurized solid particles by pressurizing gas into solid micro particles, mixing the pressurized solid particles with a graphene oxide dispersion liquid, removing liquid nitrogen under high pressure and low temperature such that the graphene oxide flakes enwrap around the pressurized solid particles, obtaining a graphene oxide block containing the pressurized solid particles by extruding, sublimating the pressurized solid particles in the graphene oxide block into gas, forming holes in the graphene oxide block and annealing, thereby obtaining the three-dimensional graphene. The three-dimensional graphene has a porous three-dimensional conductive network structure, which is able to be in any shape without any pollution.

Claims

1. A three-dimensional graphene antenna, which comprises a three-dimensional graphene radiation layer (1), a dielectric substrate (3), a metal layer (4) and a feeder line (2), wherein the three-dimensional graphene radiation layer (1) is attached to a top surface of the dielectric substrate (3), the metal layer (4) is attached to a bottom surface of the dielectric substrate (3), the feeder line (2) is provided at one side of the three-dimensional graphene radiation layer (1) and on the dielectric substrate (3).

2. The three-dimensional graphene antenna according to claim 1, wherein the three-dimensional graphene radiation layer (1) is made from porous three-dimensional graphene.

3. The three-dimensional graphene antenna according to claim 1, wherein the dielectric substrate (3) is made from a low dielectric constant material with a dielectric constant lower than 2.7.

4. A preparation method of the three-dimensional graphene antenna according to claim 1, wherein the preparation method comprises steps of: (A) selecting a material with low dielectric constant as a dielectric substrate (3); (B) preparing the three-dimensional graphene radiation layer (1) which comprises: (B1) under low temperature and high pressure, pressurizing gas whose intermolecular force is greater than repulsive force into a solid, and crushing the solid into solid micro particles which are pressurized solid particles; (B2) preparing graphene flakes with Hummers method, obtaining a graphene oxide dispersion liquid by distributing the graphene flakes in liquid nitrogen below −200° C. under the high pressure and the low temperature; (B3) obtaining a mixed solution containing the pressurized solid particles and the graphene oxide flakes by adding the pressurized solid particles into the graphene oxide dispersion liquid, removing the liquid nitrogen in the mixed solution and the graphene oxide flakes enwrapping around the pressurized solid particles by increasing a temperature of the mixed solution under the high pressure, wherein the increased temperature is lower than a sublimation temperature of the pressurized solid particles, such that the pressurized solid particles exist stably, and obtaining a graphene oxide block containing the pressurized solid particles by extruding after all of the graphene oxide flakes in the mixed solution enwrapping around the pressurized solid particles; and (B4) sublimating the pressurized solid particles in the graphene oxide block into gas by increasing a temperature and decreasing a pressure of the graphene oxide block, forming holes in the graphene oxide block, obtaining the porous three-dimensional graphene by annealing in a vacuum condition, and obtaining the three-dimensional graphene radiation layer (1) by transferring the porous three-dimensional graphene to the top surface of the dielectric substrate (3); and (C) preparing the feeder line (2) and the metal layer (4), which comprises: (C1) plating a layer of metal on the bottom surface of the dielectric substrate (3) as the metal layer (4), wherein a stable radiation field is formed between the metal layer (4) and the three-dimensional graphene radiation layer (1); and (C2) depositing a metal strip as the feeder line (2) at one side of the three-dimensional graphene radiation layer (1) for transmitting signals produced by the radiation field, thereby obtaining the three-dimensional graphene antenna.

5. The preparation method according to claim 4, wherein the low temperature is in a range of −30° C. and −100° C., and the high pressure is in a range of 0.3 Pa and 5 Pa.

6. The preparation method according to claim 4, wherein the pressurized solid particles have a size in a range of 50 nm and 1 μm.

7. The preparation method according to claim 4, wherein in the step (B3), the liquid nitrogen in the mixed solution is removed by increasing the temperature in a range of −200° C. and −120° C., which is able to ensure volatilization of the liquid nitrogen, and the solid micro particles formed by gas condensation do not volatilized.

8. The preparation method according to claim 4, wherein a density of the holes is determined by a quantity of the solid micro particles in the graphene oxide dispersion liquid.

9. The preparation method according to claim 4, wherein a size of each of the holes is determined by a size of each of the solid micro particles.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 is a structurally schematic view of a three-dimensional graphene antenna provided by the present invention.

[0028] FIG. 2 is a flow chart of preparing the three-dimensional graphene antenna.

[0029] FIG. 3 shows graphene oxide enwraps around pressurized solid particles.

[0030] FIG. 4 is a structurally schematic view of three-dimensional graphene.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0031] In order to make the technical solutions and advantages of the present invention clearer, the present invention will be explained in detail with reference to the drawings and specific embodiments as follows.

[0032] Referring to FIG. 1, a three-dimensional graphene antenna according to a preferred embodiment of the present invention is illustrated, which comprises a three-dimensional graphene radiation layer 1, a dielectric substrate 3, a metal layer 4 and a feeder line 2, wherein the three-dimensional graphene radiation layer 1 is attached to a top surface of the dielectric substrate 3, the metal layer 4 is attached to a bottom surface of the dielectric substrate 3, the feeder line 2 is provided at one side of the three-dimensional graphene radiation layer 1 and on the dielectric substrate 3 for transmitting radiation field signals formed between the three-dimensional graphene radiation layer 1 and the metal layer 4.

[0033] A preparation method of the three-dimensional graphene antenna comprises steps as follows.

[0034] (1) Preparation of a Graphene Oxide Dispersion Liquid

[0035] Referring to FIG. 2, weigh 5 g of natural graphite flakes and 2.5 g of NaNO.sub.3 powders, respectively, add the natural graphite flakes and the NaNO.sub.3 powders into 130 ml of a H.sub.2SO.sub.4 solution with a concentration of 98 wt %, obtain an intermediate solution by stirring continuously for 2 h under ice bath conditions after mixing uniformly, weigh 15 g of KMnO.sub.4 powers, put the KMnO.sub.4 powers and the intermediate solution into a reaction beaker, react for 2 h, perform a water bath on the reaction beaker under 37° C. for 1 h, increase a temperature of the water bath to 98° C., add 230 ml of deionized water into the reaction beaker, react for 30 min, add 400 ml of deionized water and 10 ml of H.sub.2O.sub.2 into the reaction beaker, stir for 1 h with a magnetic stirrer, remove SO.sub.4.sup.2− by washing with an HCl solution with a concentration of 37.5 wt %, repeatedly wash with a certain amount of deionized water till PH=7, obtain a graphene oxide solution, obtain graphene oxide flakes by performing centrifugal drying annealing treatment on the graphene oxide solution, and obtain the graphene oxide dispersion liquid by distributing uniformly the graphene oxide flakes in liquid nitrogen below −200° C. under high pressure, which is able to maintain excellent electrical and thermal properties of graphene oxide.

[0036] (2) Preparation of Pressurized Solid Particles (Taking Dry Ice as an Example)

[0037] Referring to FIG. 2, firstly pressurize CO.sub.2 to above 0.52 MPa, obtain liquid CO.sub.2 by liquefying the pressurized CO.sub.2 through cooling, obtain solid CO.sub.2 by throttling and cooling the liquid CO.sub.2 to −56.6° C. and below 0.52 MPa, grind the solid CO.sub.2 into solid microparticles which are the pressurized solid particles with a size in a range of 50 nm to 1 μm.

[0038] (3) Preparation of Porous Three-Dimensional Graphene

[0039] Referring to FIG. 2, fill an indentation, having a length of 2 cm, a width of 1 cm and a height of 0.5 μm, with the pressurized solid particles, put a certain amount of the prepared graphene oxide dispersion liquid into the indentation, wherein the certain amount of the prepared graphene oxide dispersion liquid just covers the pressurized solid particles, remove the liquid nitrogen in the graphene oxide dispersion liquid by increasing to a temperature in a range of −120° C. and −200° C. under high pressure such that the graphene oxide flakes enwrap around the pressurized solid particles, obtain a graphene oxide block (as shown in FIG. 3) by extruding after all of the graphene oxide flakes enwrapping around the pressurized solid particles, wherein the graphene oxide block contains the pressurized solid particles, volatilize the pressurized solid particles in the graphene oxide block by putting the graphene oxide block under normal temperature and pressure, form holes in the graphene oxide block, and anneal, thereby obtaining the porous three-dimensional graphene (as shown in FIG. 4).

[0040] (4) Preparation of the Three-Dimensional Graphene Antenna

[0041] Clean a dielectric substrate, deposit a metal layer with a thickness of 0.5 μm on a bottom surface of the dielectric substrate in a mixed atmosphere of Ar and O.sub.2, obtain a three-dimensional graphene radiation layer by transferring the porous three-dimensional graphene on a top surface of the dielectric substrate, and deposit a metal strip which acts as a feeder line at one side of the porous three-dimensional graphene, thereby obtaining the three-dimensional graphene antenna.