CN113161733B - Graphene-based flexible broadband monopole wearable antenna - Google Patents

Abstract

The invention relates to a graphene-based flexible broadband monopole wearable antenna, comprising: a flexible dielectric substrate, a common ground structure and a radiation unit arranged on the flexible dielectric substrate, wherein the common ground structure is located above the radiation unit, The electrical network is connected with the radiation unit, and the common ground structure is used to widen the working bandwidth of the wearable antenna; the radiation unit is in the form of a plane monopole, including the feeding conductive strips connected in sequence, the first transition connection part, the rectangular slot antenna part, the second Transition connection part and U-slot antenna part. The graphene-based flexible broadband monopole wearable antenna of the present invention bends the radiation patch part in the form of a monopole antenna, and forms a rectangular slot and a U-shaped slot for the antenna, which prolongs the current path and increases the antenna power. length, so as to realize the broadband and miniaturization characteristics of the antenna. The common ground structure broadens the working bandwidth of the wearable antenna, thereby broadening the application prospect of the wearable antenna.

Description

A graphene-based flexible broadband monopole wearable antenna

technical field

The invention belongs to the technical field of antennas, and in particular relates to a graphene-based flexible broadband monopole wearable antenna.

Background technique

With the vigorous development of wireless communication technology and the rise of wearable electronic devices, human-centered wireless communication systems have become one of the research hotspots today. As an important part of modern mobile communication, human body wireless communication system plays an important role in the fields of medical assistance, health monitoring, entertainment and leisure, and fire rescue. As an indispensable radio device for transmitting and receiving electromagnetic waves, the antenna is an important part of the wireless communication system. The performance of the antenna will directly affect the quality of the communication system. In order to meet the quality and comfort requirements of human communication, it is particularly important to study a wearable antenna with the characteristics of flexibility, light weight, and low profile.

The research on wearable antenna can be roughly divided into the following three aspects: 1. Research on wearable antenna model; 2. Material application of wearable antenna; 3. Interaction between wearable antenna and human body. With the development of software radio, the research of VHF/UHF broadband omnidirectional antenna has attracted more and more scholars' attention. The current wearable antennas mainly include monopole form and microstrip patch form. The monopole antenna has a simple structure and is easy to achieve broadband, but this type of antenna has a large impact on the human body (high SAR value), and is usually large in size and inconvenient to install. The microstrip patch antenna can isolate the human body from the antenna, but its bandwidth is narrow, and the performance of the antenna will decrease with the change of shape. Moreover, the flexibility of the patch antenna is poor, which does not meet the needs of the human body for comfort. In addition, most of the wearable antennas are piggyback antennas, which are relatively large when they are extended. It is extremely inconvenient for soldiers to travel through combat environments such as jungles, it is difficult to adapt to various tactical actions of fighters, and the concealment is poor.

SUMMARY OF THE INVENTION

In order to solve the above problems existing in the prior art, the present invention provides a graphene-based flexible broadband monopole wearable antenna. The technical problem to be solved by the present invention is realized by the following technical solutions:

The present invention provides a graphene-based flexible broadband monopole wearable antenna, comprising: a flexible dielectric substrate, a common ground structure and a radiation unit disposed on the flexible dielectric substrate, wherein,

The common ground structure is located above the radiation unit and is connected to the radiation unit through a feeding network, and the common ground structure is used to widen the working bandwidth of the wearable antenna;

The radiating element is in the form of a plane monopole, and includes a feeding conductive strip, a first transition connection part, a rectangular slot antenna part, a second transition connection part and a U-shaped slot antenna part connected in sequence, wherein,

The feeding conductive strip is a vertically arranged rectangular structure;

The rectangular slot antenna part is obliquely arranged below the feeding conductive strip, and is connected to the feeding conductive strip through the first transition connection part, and the angle between the rectangular slot antenna part and the vertical direction is 70°-77° °, a plurality of rectangular grooves are arranged at intervals on the upper and lower sides, and the rectangular grooves on the upper and lower sides are arranged in a staggered manner;

The U-shaped slot antenna part includes a first antenna unit and a second antenna unit, one end of the first antenna unit is connected to the rectangular slot antenna part through the second transition connecting part, and the other end is provided with a rectangular convex Since then, the second antenna unit is provided with a U-shaped groove matching the rectangular protrusion, the rectangular protrusion is located in the U-shaped groove, and there is a space between the rectangular protrusion and the U-shaped groove.

In an embodiment of the present invention, the feeding conduction band has a length of 0.07λ _g -0.1λ _g and a width of 0.01λ _g -0.02λ _g , where λ _g is the wavelength of the dielectric waveguide.

In an embodiment of the present invention, the width of the rectangular grooves is ≤15 mm, the depth is 0.01λ _g -0.02λ _g , and the distance between adjacent rectangular grooves is 0.03λ _g -0.18λ _g , where λ _g is the wavelength of the dielectric waveguide.

In an embodiment of the present invention, in the rectangular slot antenna portion, the width of the end portion connecting the first transition connecting portion is smaller than the width of the end portion connecting the second transition connecting portion.

In an embodiment of the present invention, the length of the rectangular protrusion is 0.02λ _g -0.05λ _g , where λ _g is the wavelength of the dielectric waveguide.

In an embodiment of the present invention, the width of the U-shaped groove is less than or equal to 0.05λ _g , and the distance between the rectangular protrusion and the U-shaped groove is less than or equal to 15 mm, where λ _g is the wavelength of the dielectric waveguide.

In an embodiment of the present invention, in the U-shaped slot antenna part, the width of the end connecting the second transition connecting part is larger than the width of the other end.

In an embodiment of the present invention, the first transition connecting portion is a bent structure, and the second transition connecting portion is a rectangular structure.

In an embodiment of the present invention, the material of the flexible medium substrate is a flexible polyester resin material.

In an embodiment of the present invention, the material of the common ground structure and the radiation unit is a graphene conductive thin film material.

Compared with the prior art, the beneficial effects of the present invention are:

1. The graphene-based flexible broadband monopole wearable antenna of the present invention bends the radiation patch part of the monopole antenna form, and opens a rectangular slot and a U-shaped slot to the antenna, extending the current path, increasing the The electrical length of the antenna can be used to realize the broadband and miniaturization characteristics of the antenna.

2. The graphene-based flexible broadband monopole wearable antenna of the present invention, the common ground structure on one side of the antenna feed end, can be any form of antenna or an antenna arm to widen the work of the wearable antenna bandwidth, thereby broadening the application prospects of wearable antennas.

3. The graphene-based flexible broadband monopole wearable antenna of the present invention adopts a graphene film material with high conductivity as a radiation unit and a common ground structure material, which ensures high conductivity and realizes the light weight of the wearable antenna. characteristics.

4. The graphene-based flexible broadband monopole wearable antenna of the present invention utilizes the flexible characteristics of the flexible dielectric layer and the graphene conductive film, so that the wearable antenna has good bending resistance and chemical stability, and improves the wearability. Wear the conformal effect of the antenna and the clothing to meet the human body's requirements for the comfort of the clothing.

The above description is only an overview of the technical solutions of the present invention, in order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand , the following specific preferred embodiments, and in conjunction with the accompanying drawings, are described in detail as follows.

Description of drawings

1 is a schematic structural diagram of a graphene-based flexible broadband monopole wearable antenna provided by an embodiment of the present invention;

2 is a schematic structural diagram of a radiation unit provided by an embodiment of the present invention;

3 is a schematic structural diagram of a common ground structure provided by an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a flexible dielectric substrate provided by an embodiment of the present invention;

5 is a schematic diagram of the state of the graphene-based flexible broadband monopole wearable antenna provided by the embodiment of the present invention after it is loaded on the human body;

6 is a comparison diagram of S11 parameters before and after the graphene-based flexible broadband monopole wearable antenna of the present invention is loaded on the human body;

FIG. 7 is a comparison diagram of the achievable gain before and after the graphene-based flexible broadband monopole wearable antenna of the present invention is loaded on the human body.

Detailed ways

In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, a graphene-based flexible broadband monopole wearable antenna proposed by the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. .

The foregoing and other technical contents, features and effects of the present invention can be clearly presented in the following detailed description of the specific implementation with the accompanying drawings. Through the description of the specific embodiments, the technical means and effects adopted by the present invention to achieve the predetermined purpose can be more deeply and specifically understood. However, the accompanying drawings are only for reference and description, and are not used for the technical description of the present invention. program is restricted.

Example 1

Please refer to FIG. 1 and FIG. 2 in combination. FIG. 1 is a schematic structural diagram of a graphene-based flexible broadband monopole wearable antenna provided by an embodiment of the present invention; FIG. 2 is a schematic diagram of a radiation unit provided by an embodiment of the present invention. Schematic. As shown in the figure, the graphene-based flexible broadband monopole wearable antenna includes: a flexible dielectric substrate 1 , a common ground structure 2 and a radiation unit 3 disposed on the flexible dielectric substrate 1 . The common ground structure 2 is located above the radiation unit 3, and the common ground structure 2 is connected to the radiation unit 3 through a feeding network. The common ground structure 2 is used to widen the working bandwidth of the wearable antenna. The radiating element 3 is in the form of a planar monopole to achieve a wider impedance bandwidth.

Further, the radiation unit 3 includes a feeding conductive strip 301 , a first transition connection part 302 , a rectangular slot antenna part 303 , a second transition connection part 304 and a U-shaped slot antenna part 305 , which are connected in sequence.

In this embodiment, the feeding conductive strip 301 is a vertically arranged rectangular structure. The common ground structure 2 is connected to the feeding conductive strip 301 through the feeding network. The feeding conductive strip 301 is used to realize the transition between the feeding part and the radiating body.

c为真空中的光速，ε_e为辐射单元介质板的有效介电常数，f₀为可穿戴天线的中心频率。用于保证在能量有效地馈入的同时，利于在腰部对天线进行馈电，贴合实际应用场景。Optionally, the length L2 of the feeding conduction band 301 is 0.07λ _g -0.1λ _g , and the width W2 is 0.01λ _g -0.02λ _g , where λ _g is the wavelength of the dielectric waveguide,

c is the speed of light in vacuum, ε _e is the effective dielectric constant of the radiating element dielectric plate, and f ₀ is the center frequency of the wearable antenna. It is used to ensure that the energy is effectively fed in, and it is beneficial to feed the antenna at the waist, which is suitable for practical application scenarios.

It should be noted that, in this embodiment, the common ground structure 2 is used to provide the equivalent "ground" of the antenna, which can be an antenna in any frequency band or an antenna arm to widen the working bandwidth of the wearable antenna.

Further, the rectangular slot antenna portion 303 is obliquely arranged below the feed conductive strip 301, and is connected to the feed conductive strip 301 through the first transition connection portion 302, and the angle α between the rectangular slot antenna portion 303 and the vertical direction is 70°-77° , to meet the size requirements of the antenna, and to achieve a good conformal effect with the human body, and it is also conducive to feeding in the waist area.

Further, a plurality of rectangular slots 3031 are provided at intervals on the lower two sides of the rectangular slot antenna portion 303 , and the rectangular slots 3031 on the upper and lower sides are arranged in a staggered manner.

In this embodiment, the total number of rectangular slots 3031 is not less than 6 to increase the electrical length of the antenna. The width of the rectangular slot 3031 should not be too wide to ensure the structural stability and meandering effect of the radiation unit 3 .

Optionally, the width g1 of the rectangular grooves 3031 is less than or equal to 15 mm, the depth L6 is 0.01λ _g -0.02λ _g , the spacing W6 between adjacent rectangular grooves 3031 is 0.03λ _g -0.18λ _g , where λ _g is the dielectric waveguide wavelength.

Further, the U-shaped slot antenna portion 305 includes a first antenna unit 3051 and a second antenna unit 3052, one end of the first antenna unit 3051 is connected to the rectangular slot antenna portion 303 through the second transition connecting portion 304, and the other end is provided with a rectangular slot antenna portion 303. Protrusion, the second antenna unit 3052 is provided with a U-shaped groove matching the rectangular protrusion, the rectangular protrusion is located in the U-shaped groove, and there is a space between the U-shaped groove and the U-shaped groove.

In this embodiment, the U-shaped groove is used to improve the impedance characteristics within the band. Optionally, the length L8 of the rectangular protrusion is 0.02λ _g -0.05λ _g , and the width W8 of the U-shaped groove is ≤ 0.05λ _g , where λ _g is the wavelength of the dielectric waveguide. The distance between the rectangular protrusion and the U-shaped groove should not be too wide. Preferably, the distance g2 between the rectangular protrusion and the U-shaped groove is less than or equal to 15 mm.

It should be noted that, in the rectangular slot antenna portion 303 , the width of the end portion connected to the first transitional connection portion 302 is smaller than the width of the end portion connected to the second transitional connection portion 304 . In the U-shaped slot antenna portion 305, the width of the end connecting the second transition connecting portion 304 is larger than the width of the other end thereof.

In this embodiment, the “narrow-wide-narrow” gradient structure of the radiation unit 3 can ensure the helical effect when the antenna is conformal to the human body.

Further, in this embodiment, the first transition connecting portion 302 is a bending structure, which is composed of a rectangular bending portion and a trapezoidal portion, and the second transition connecting portion 304 is a rectangular structure. It should be noted that the first transition connection part 302 and the second transition connection part 304 are used to realize the connection between the feeding conductive strip 301 and the rectangular slot antenna part 303, and the connection between the rectangular slot antenna part 303 and the U-shaped slot antenna part 305, Its specific shape is not limited, and it only needs to realize the connection between the feeding conductive strip 301 and the rectangular slot antenna part 303 and the connection between the rectangular slot antenna part 303 and the U-shaped slot antenna part 305 .

Further, considering the convenience of wearing the antenna, optionally, the horizontal size range of the radiation unit 3 is 0.38λ _g ≤ L1 ≤ 0.58λ _g , and the vertical size range is 0.21λ _g ≤ H1 ≤ 0.32λ _g , wherein, λ _g is the wavelength of the dielectric waveguide.

It should be noted that the flexible dielectric substrate 1 is used as the support structure of the common ground structure 2 and the radiation unit 3. The size of the flexible dielectric substrate 1 should be greater than or equal to the size of the common ground structure 2 and the radiation unit 3, so as to ensure the common ground structure 2 and the radiation unit 3. The radiation unit 3 is supported by a medium.

Further, in this embodiment, the material of the flexible medium substrate 1 is a flexible polyester resin material, so as to ensure the flexibility of the entire antenna and meet the comfort requirements of the human body.

Further, in this embodiment, the materials of the common ground structure 2 and the radiation unit 3 are graphene conductive thin film materials, so as to reduce the weight of the entire antenna and make the antenna have good bending resistance and chemical stability. Optionally, the common ground structure 2 and the radiation unit 3 use a graphene conductive film with a bulk conductivity of 1,100,000 S/m and a thickness of 25 μm

In this embodiment, the overall line width of the radiation unit 2 (the average width of the radiation unit 2 ) is wider, and the equivalent resistance thereof is relatively small, thereby reducing the impedance and reducing the loss caused by the high-conductivity graphene.

For the flexible broadband monopole wearable antenna based on graphene in this embodiment, the radiation patch in the form of a monopole antenna is partially bent, and a rectangular slot and a U-shaped slot are formed for the antenna, which prolongs the current path and increases the number of antennas. Electric length, so as to realize the broadband and miniaturization characteristics of the antenna. The common ground structure on one side of the antenna feed end can be any form of antenna or an antenna arm, so as to widen the working bandwidth of the wearable antenna, thereby broadening the application prospect of the wearable antenna.

The graphene-based flexible broadband monopole wearable antenna of this embodiment adopts a graphene film material with high conductivity as the radiating element and the common ground structure material, which ensures high conductivity and realizes the lightweight and lightweight of the wearable antenna. characteristic. In addition, using the flexible characteristics of the flexible dielectric layer and the graphene conductive film, the wearable antenna has good bending resistance and chemical stability, which improves the conformal effect of the wearable antenna and the clothing, so as to meet the comfort of the human body to the clothing. requirements.

Embodiment 2

In this embodiment, the graphene-based flexible broadband monopole wearable antenna in Embodiment 1 is simulated in conjunction with the human body to evaluate the influence of the human body on the performance of the antenna.

Specifically, the common ground structure 2 and the radiation unit 3 use a graphene conductive film with a bulk conductivity of 1,100,000 S/m and a thickness of 25 μm.

Please refer to FIG. 3 and FIG. 4 in conjunction. FIG. 3 is a schematic structural diagram of a common ground structure provided by an embodiment of the present invention; FIG. 4 is a structural schematic diagram of a flexible dielectric substrate provided by an embodiment of the present invention. The structural parameters of the graphene-based flexible broadband monopole wearable antenna of this embodiment are described as follows:

The flexible dielectric substrate 1 is made of polyester resin material with dielectric constant ε _e =2.7. The length l and width w of the flexible medium substrate 1 are respectively l=147.3 cm and w=105 cm, and the thickness d of the flexible medium substrate 1 is 0.05 mm.

The common ground structure 2 is represented by one arm of a dipole antenna, the shape is a trapezoid, the length of the upper base L9=8cm, the length of the lower base L10=118cm, and the height H2=20cm.

As shown in FIG. 2 , the horizontal length L1 = 147.3 cm and the vertical height H1 = 80.3 cm of the radiation unit 3 . In the radiation unit 3 , the length L2 = 265 mm and the width W2 = 60 mm of the feeding conductive strip 301 . In the first transition connecting portion 302, the dimensions of the rectangular bending portion are: L3=300mm, W3=110mm, L4=220mm, W4=70mm; the upper bottom of the trapezoid portion is L5=120mm, the lower bottom is the same length as L4, and the waist The angle with the vertical direction is 45°. The angle α between the rectangular slot antenna portion 303 and the vertical direction is 74°. In the rectangular slot antenna portion 303, the total number of rectangular slots 3031 is 8, the width of the rectangular slot 3031 is g1=5mm, and the depth L6=52.5mm. The distance between adjacent rectangular grooves 3031 is W6=125mm. The dimensions of the second transition connecting portion 304 are: W7=158mm, L7=510mm. In the U-shaped groove antenna part 305, the length of the rectangular protrusion L8=130mm, the width of the U-shaped groove W8=73mm, the distance between the rectangular protrusion and the U-shaped groove g2=8mm, the distance between the sides of the rectangular protrusion The distance W9 from the edge of the first antenna unit 3051 is 25 mm.

The above graphene-based flexible broadband monopole wearable antenna and the human body were co-simulated using the electromagnetic field full-wave simulation software ANSYS HFSS 19.0, in which the operating frequency band was 30-108MHz. Please refer to FIG. 5. FIG. 5 is a schematic diagram of the state of the graphene-based flexible broadband monopole wearable antenna provided by the embodiment of the present invention after being loaded on the human body, wherein the human body adopts the human body model provided by the XFDTD simulation software agent Weier Technology. , the common ground structure 2 is located at the waist of the human body, and the radiation unit 3 is wound around the area of the right leg of the human body. Considering the actual wearing situation, the height of the bottom end of the radiation unit 3 is H3=10cm from the ground.

Simulation content:

Simulation 1, the S-parameters of the graphene-based flexible broadband monopole wearable antenna in this embodiment are simulated respectively, please refer to FIG. 6, FIG. 6 is the loading of the graphene-based flexible broadband monopole wearable antenna of the present invention. Comparison of S11 parameters before and after the human body. The abscissa in the figure is the frequency, the unit is MHz, and the range is from 30-108MHz. The ordinate is the decibel value of the S parameter amplitude, the unit is dB, and the range is -25dB-0dB. S11 represents the reflection coefficient of the feed port.

It can be seen from FIG. 6 that when the graphene-based flexible broadband monopole wearable antenna is not conformal to the human body, S11<-5dB (corresponding to VSWR<3.5) in the 30-108MHz part of the frequency band (corresponding to VSWR<3.5). The graphene-based flexible broadband monopole wearable antenna has poor S11 matching in a wide frequency band, and cannot achieve efficient energy transmission in a short-wave broadband frequency band. After being loaded in the right leg region of the human body, the S11 curve of the antenna is improved, and the relative bandwidth corresponding to the standing wave ratio VSWR < 3.5 is further broadened, which indicates that the graphene-based flexible broadband wearable antenna of this embodiment has the characteristics of broadband.

Simulation 2, simulate the achievable gain of the graphene-based flexible broadband monopole wearable antenna of the present embodiment, please refer to FIG. 7 , FIG. 7 is the loading of the graphene-based flexible broadband monopole wearable antenna of the present invention Comparison of achievable gains before and after the human body. The abscissa in the figure is the frequency, the unit is MHz, and the range is from 30-108MHz, and the ordinate is the decibel value of the achievable gain amplitude, the unit is dB, and the range is -25dB-5dB.

It can be seen from Fig. 7 that the graphene-based flexible broadband monopole wearable antenna of this embodiment is simulated separately, and the average gain of the whole frequency band is about -3dB; after being loaded in the right leg area of the human body, the achievable gain of the antenna decreases to some extent. , but still achieve an average gain of about -10dB, which indicates that the graphene-based flexible broadband monopole wearable antenna has good radiation characteristics in the short-wave band.

The graphene-based flexible broadband monopole wearable antenna in this embodiment solves the problems of large size and narrow operating bandwidth of traditional VHF band wearable antennas. And the use of graphene conductive film instead of traditional metal makes the antenna have good flexibility and reduces the weight of the antenna to meet the comfort requirements of the human body for wearable devices.

It should be noted that, in this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any relationship between these entities or operations. any such actual relationship or sequence exists. Moreover, the terms "comprising", "comprising" or any other variation are intended to encompass a non-exclusive inclusion, whereby an article or device comprising a list of elements includes not only those elements, but also other elements not expressly listed. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in the article or device that includes the element. Words like "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The orientation or positional relationship indicated by "up", "bottom", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying The device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention.

The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be considered that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field of the present invention, without departing from the concept of the present invention, some simple deductions or substitutions can be made, which should be regarded as belonging to the protection scope of the present invention.

Claims (9)

1. A flexible broadband monopole wearable antenna based on graphene, comprising: a flexible dielectric substrate, and a common ground structure and a radiating element disposed on the flexible dielectric substrate,

the common ground structure is located above the radiating unit and connected with the radiating unit through a feed network, and the common ground structure is used for widening the working bandwidth of the wearable antenna;

the radiation unit adopts a planar monopole form and comprises a feed conduction band, a first transition connecting part, a rectangular slot antenna part, a second transition connecting part and a U-shaped slot antenna part which are connected in sequence, wherein,

the feed conduction band is of a vertically arranged rectangular structure;

the rectangular slot antenna part is obliquely arranged below the feed conduction band and is connected with the feed conduction band through the first transition connecting part, the included angle between the rectangular slot antenna part and the vertical direction is 70-77 degrees, a plurality of rectangular slots are arranged at intervals on the upper side and the lower side of the rectangular slot antenna part, and the rectangular slots on the upper side and the lower side are arranged in a staggered manner;

the U-shaped groove antenna part comprises a first antenna unit and a second antenna unit, one end of the first antenna unit is connected with the rectangular groove antenna part through the second transition connecting part, the other end of the first antenna unit is provided with a rectangular bulge, the second antenna unit is provided with a U-shaped groove matched with the rectangular bulge, the rectangular bulge is positioned in the U-shaped groove, and a space is reserved between the rectangular bulge and the U-shaped groove;

the materials of the common ground structure and the radiation unit are graphene conductive thin film materials.

2. The graphene-based flexible broadband monopole wearable antenna according to claim 1, wherein the length of the feed conduction band is 0.07 λ_g-0.1λ_gWidth of 0.01 lambda_g-0.02λ_gWherein λ is_gIs a dielectric waveguide wavelength.

3. The graphene-based flexible broadband monopole wearable antenna according to claim 1, wherein the rectangular groove has a width of 15mm or less and a depth of 0.01 λ_g-0.02λ_gThe distance between adjacent rectangular grooves is 0.03 lambda_g-0.18λ_gWherein λ is_gIs a dielectric waveguide wavelength.

4. The flexible graphene-based broadband monopole wearable antenna according to claim 1, wherein in the rectangular slot antenna portion, a width of an end connecting the first transition connection portion is less than a width of an end connecting the second transition connection portion.

5. The graphene-based flexible broadband monopole wearable antenna according to claim 1, wherein the length of the rectangular protrusion is 0.02 λ_g-0.05λ_gWherein λ is_gIs a dielectric waveguide wavelength.

6. The graphene-based flexible broadband monopole wearable antenna according to claim 1, wherein the width of the U-shaped groove is less than or equal to 0.05 λ_gThe distance between the rectangular protrusion and the U-shaped groove is less than or equal to 15mm, wherein lambda is_gIs a dielectric waveguide wavelength.

7. The graphene-based flexible broadband monopole wearable antenna according to claim 1, wherein in the U-shaped slot antenna portion, a width of an end portion connecting the second transition connection portion is greater than a width of the other end thereof.

8. The graphene-based flexible broadband monopole wearable antenna according to claim 1, wherein the first transition connection portion is a bent structure and the second transition connection portion is a rectangular structure.

9. The graphene-based flexible broadband monopole wearable antenna according to claim 1, wherein the flexible dielectric substrate is made of a flexible polyester resin material.

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