Low-frequency lightweight high-gain antenna

Abstract

The invention relates to a low-frequency lightweight high-gain antenna, and relates to the technical field of compact range feed source antennas. The low-frequency lightweight high-gain antenna provided by the invention comprises a dielectric radiation section, a foam support section and a balanced feed section, the dielectric radiation section is composed of a plurality of concentric dielectric cylinders, electromagnetic waves can be radiated out, the antenna gain can be improved, and the foam supporting section is used for supporting the radiation section, so that a certain distance condition is met between the dielectric radiation section and the feed section. The radiation section adopts a balanced feed mode to excite the antenna, and dual polarization is realized at the same time. The antenna provided by the invention has the advantages of simple structure, low processing cost, high gain, light weight, wide bandwidth and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of compact range feed antennas, and in particular to a low-frequency, lightweight, high-gain antenna. Background Art

[0002] Antennas are an important part of wireless communication systems. Traditional antenna designs are often based on the wavelength of the antenna's operating frequency. The lower the frequency, the longer the operating wavelength, and the larger and heavier the corresponding antenna design. This is inconvenient to use. The challenges faced by low-frequency antenna design include: how to reduce the size of low-frequency antennas and how to reduce the weight of antennas. In order to solve the above problems, the following low-frequency antennas have emerged:

[0003] Short vertical antenna: Short vertical antenna is a common low-frequency antenna design, which can achieve low-frequency operation by constraining the antenna length to a few fractions of the wavelength. However, short vertical antennas will produce a large binding effect, resulting in low radiation efficiency, low gain, and susceptibility to interference from the surrounding environment.

[0004] Magnetic loop antenna: Magnetic loop antenna is an antenna design that bends a wire into a loop. It can achieve low frequency operation and has a low profile. However, magnetic loop antennas have a narrow bandwidth problem in the frequency range and are sensitive to antenna materials and grounding conditions.

[0005] Helical antenna: Helical antenna is an antenna design that bends the plane of the wire into a spiral shape. It can achieve low frequency operation and has a lower profile, but it leads to space limitations in practical applications.

[0006] Antenna array: Antenna array is a kind of low-frequency work achieved by combining multiple antenna elements together. Antenna array can achieve directional radiation and gain enhancement by controlling the phase and amplitude of each antenna element. However, the manufacture and adjustment of antenna array is relatively complex, with high requirements for system design and electronic tuning, high requirements for the consistency of antenna array, and complex composition.

[0007] These methods have certain limitations in realizing low-frequency and low-profile antennas, including problems in radiation efficiency, bandwidth, size, complexity, etc. The present invention designs a low-frequency, lightweight, high-gain antenna that can effectively improve the above problems. Summary of the invention

[0008] The present invention provides a low-frequency, lightweight, high-gain antenna having the advantages of simple structure, low processing cost, high gain, light weight, wide bandwidth, etc.

[0009] In a first aspect, the present invention provides a low-frequency, lightweight, high-gain antenna, comprising: a dielectric radiation section, a foam support section, and a balanced feed section;

[0010] The dielectric radiation section is composed of a plurality of concentric curved dielectric columns with different heights, diameters and dielectric constants; the dielectric constants of the dielectric columns gradually decrease from the inside to the outside; the dielectric radiation section excites the antenna by a balanced feeding method and realizes dual polarization at the same time;

[0011] The foam support section is used to support the dielectric radiation section so that the dielectric radiation section and the balanced feeding section meet the set distance condition;

[0012] The balanced feeding section provides a feeding signal for the antenna, and combined with the use of a 180° bridge, generates a potential difference on the symmetrical feeding array to achieve broadband single-mode excitation.

[0013] In a second aspect, the present invention provides a design method for a low-frequency, lightweight, high-gain antenna, comprising:

[0014] Model the dielectric radiation section, foam support section and balanced feed section in the simulation environment, define the size range and the outer wall curve equation of each curved dielectric column;

[0015] In the simulation environment, obtain the frequency radiation direction and gain curve of the antenna within the specified frequency band;

[0016] Within the size range, the sizes of the dielectric radiation section, the foam support section and the balanced feeding section are optimized respectively so that the frequency radiation direction and the gain curve meet the set requirements.

[0017] The technical solution adopted by the present invention is as follows: the antenna is composed of a dielectric radiation section, a foam support section, and a balanced feeding section; the antenna radiation section is composed of a plurality of concentric dielectric columns, which can radiate electromagnetic waves and improve the antenna gain; the foam support section is used to support the dielectric radiation section so that a certain distance condition is met between the dielectric radiation section and the feeding section. The dielectric radiation section uses a balanced feeding method to excite the antenna and realize dual polarization at the same time. The height of the entire antenna is 1.3λ~1.4λ (λ is the wavelength corresponding to the lowest operating frequency), and the diameter is between 2.6λ~2.7λ, which can achieve a bandwidth of 1.8 times the frequency; the gain can reach 15dBi.

[0018] The principle of the present invention is that the electromagnetic waves excited by the feeding section are transmitted between the flat plate outside the feeding cabin and the upper dielectric radiation section, and the high dielectric constant dielectric column in the radiation section can effectively focus the electromagnetic waves to form a directional beam pointing to the hole.

[0019] The dielectric constant of the radiating section of the patent design gradually decreases in the lateral direction, and the dielectric boundary wall adopts a curved form, and materials with different dielectric constants are nested with each other. This can expand the working bandwidth of the antenna, and the use of curved walls and layers with different dielectric constants can make the phase of the electromagnetic wave more uniform during the transmission of the working frequency, thereby enhancing the antenna directivity and gain.

[0020] The advantages of the present invention compared with the prior art are:

[0021] (1) The present invention adopts a balanced feeding and dielectric radiation section combination, which reduces the size of the entire antenna while making the feeding structure simple and easy to implement.

[0022] (2) The present invention improves the gain of the antenna within a limited size and has higher directivity.

[0023] (3) The overall area of ​​the present invention is smaller and is suitable for use in limited spaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of the structure of a low-frequency, lightweight, high-gain antenna provided by an embodiment of the present invention;

[0025] Figure 2 A schematic longitudinal cross-sectional view of a low-frequency, lightweight, high-gain antenna provided by an embodiment of the present invention;

[0026] Figure 3 A schematic cross-sectional view of a low-frequency, lightweight, high-gain antenna feed section provided in an embodiment of the present invention;

[0027] Figure 4 A schematic diagram of the structure of a low-frequency, lightweight, high-gain antenna array provided by an embodiment of the present invention;

[0028] Figure 5 A schematic diagram of a flow chart of a design method for a low-frequency, lightweight, high-gain antenna provided by an embodiment of the present invention;

[0029] Figure 6 A radiation pattern of a low-frequency, lightweight, high-gain antenna with a partial frequency of 1 GHz to 1.8 GHz provided in an embodiment;

[0030] Figure 7 A 1GHz to 1.8GHz gain curve diagram of a low-frequency, lightweight, high-gain antenna provided in an embodiment;

[0031] The symbols in the figure are as follows: 1-1 is the dielectric radiation section; 1-2 is the foam support section; 1-3 is the balanced feeding section; 1-4 is the outer plane plate of the balanced feeding section; 1-5 is the SMA connector; 2-1 is the first curved dielectric column; 2-2 is the second curved dielectric column; 2-3 is the third curved dielectric column; 2-4 is the fourth curved dielectric column; 2-5 is the feed array; 3-1 is the feed cabin; 4-1 is the first cylinder constituting the feed array, 4-2 is the second cylinder, and 4-3 is the third cylinder. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0033] Example 1

[0034] The present invention provides a low-frequency, lightweight, high-gain antenna. Figure 1 The antenna comprises a dielectric radiation section 1-1, a foam support section 1-2 and a balanced feed section 1-3. The structure and function of each section are introduced below.

[0035] The dielectric radiation section 1-1 includes a plurality of concentric curved dielectric columns with different heights, diameters and dielectric constants. The dielectric constant and height of the dielectric radiation section decrease gradually from the inside to the outside. Figure 1 The antenna also includes SMA connectors 1-5. The full name of SMA is SubMiniature version A, which is a coaxial cable connector used to connect the coaxial cable and the antenna. The function of the SMA connector is to form an electrical connection between the coaxial cable and the antenna to transmit radio frequency signals.

[0036] Schematic diagram of the longitudinal section of the antenna, see Figure 2 , the dielectric radiation section 1-1 specifically includes a first curved dielectric column 2-1, a second curved dielectric column 2-2, a third curved dielectric column 2-3 and a fourth curved dielectric column 2-4. Of course, the present invention is not limited to the aforementioned 4 curved dielectric columns, but can also be 3 curved dielectric columns or 5 curved dielectric columns, which is determined according to the required antenna performance. Since the dielectric constant of the dielectric radiation section gradually decreases from the inside to the outside, the present invention uses the dielectric constant of common materials in the market for simulation or testing, and tests the dielectric constants of various common materials in the simulation environment or during the test process to comply with the law that the dielectric constant gradually decreases from the inside to the outside. Optionally, the present invention selects the dielectric constant of the first curved dielectric column 2-1 to be 10.2, the dielectric constant of the second curved dielectric column 2-2 to be 9.2, the dielectric constant of the third curved dielectric column 2-3 to be 6.15, and the dielectric constant of the fourth curved dielectric column 2-4 to be 3.55. The heights of the four concentric curved dielectric columns decrease layer by layer from the inside to the outside. Figure 2 Feed elements 2-5 are also shown.

[0037] The invention has multiple concentric curved dielectric columns with different heights, diameters and dielectric constants, and a design with decreasing dielectric constants, which can radiate electromagnetic waves under the condition of small electrical size through the guided transition of the exponential curved dielectric columns. The use of multiple sections of dielectrics can effectively improve the antenna gain.

[0038] The foam support section 1-2 is used to support the dielectric radiation section 1-1 so that the set distance condition between the dielectric radiation section 1-1 and the balanced feeding section 1-3 is met: 0.52λ~0.54λ, to ensure that the antenna achieves optimal performance. Among them, λ is the wavelength corresponding to the lowest operating frequency of the low-frequency lightweight high-gain antenna, which can be 300mm. If the distance between the dielectric radiation section and the balanced feeding section is too large, the radiation efficiency and antenna gain will be reduced; if the distance is too small, the electromagnetic coupling between the radiation section and the feeding section will be too strong, limiting the working frequency band of the antenna.

[0039] A schematic cross-sectional view of a balanced feed section 1-3 is shown in FIG. Figure 3 , including a feed cabin 3-1, four feed arrays 2-5 and four SMA connectors 1-5, the inner conductor of each SMA connector 1-5 extends into the feed cabin 3-1 and is connected to the corresponding feed array 2-5, and the other end of the SMA connector 1-5 is externally connected to a 180° bridge, generating a potential difference on the symmetrical feed array 2-5 to achieve balanced feeding excitation. The two symmetrical feed arrays 2-5 achieve single polarization performance, and the balanced feed section 1-3 contains two groups of symmetrical feed arrays 2-5 to achieve dual polarization performance.

[0040] Example 2

[0041] The present invention provides a design method for a low-frequency, lightweight, high-gain antenna, which is suitable for designing the size parameters of a dielectric radiation section 1-1, a foam support section 1-2, and a balanced feed section 1-3 in a low-frequency, lightweight, high-gain antenna. Figure 5 The method provided in this embodiment specifically includes the following steps:

[0042] S110. Model the dielectric radiation section 1-1, the foam support section 1-2 and the balanced feeding section 1-3 in a simulation environment, and define the size range and the outer wall curve equation of each curved dielectric column.

[0043] The dielectric radiation section 1-1 includes four sections of curved dielectric columns, the materials of which are dielectric materials with four different dielectric constants; the dielectric in the feeding cabin in the balanced feeding section is air, the dielectric between the inner and outer conductors in the SMA connector is also air, and the rest are metal; the radiation section and the feeding section are connected through a foam support section, the material of the foam support section is foam, and the internal dielectric is air; the foam support section is connected to the feeding section and the radiation section by fixing with adhesive.

[0044] The dielectric radiation section 1-1 is modeled and designed, and the outer wall curve equation of each of the curved dielectric columns is:

[0045] y=A*{exp[R*(xS i )]-1};

[0046] Where A is the straightness of the curve, R is the curvature of the curve; A∈(0,1), R∈(0,0.1), S i is the bottom diameter of the i-th curved medium column, x is the independent variable of the outer wall curve equation, and y is the dependent variable of the outer wall curve equation. In the simulation environment, A of the outer wall curve equation is set to (0, 1) and R is set to (0, 0.1).

[0047] In the simulation environment, the height of the first curved dielectric column 2-1 is set to 0.38λ~0.4λ, and the corresponding S1 is 0.6λ~0.7λ; the height of the second curved dielectric column 2-2 is 0.36λ~0.38λ, and the corresponding S2 is 1.3λ~1.35λ; the height of the third curved dielectric column 2-3 is 0.34λ~0.36λ, and the corresponding S3 is 1.95λ~2λ; the height of the fourth curved dielectric column 2-4 is 0.28λ~0.3λ, and the corresponding S4 is 2.63λ~2.66λ. The thickness of the four concentric curved dielectric columns is the same. Optionally, the relationship between λ and the previous number is a product, and λ is the wavelength corresponding to the lowest operating frequency of the low-frequency lightweight high-gain antenna, which can be 300mm.

[0048] In the simulation environment, the foam support segment 1-2 is set as a hollow cylinder with an inner diameter of 0.65λ to 0.68λ, an outer diameter of 2.63λ to 2.66λ, and a height of 0.52-0.54λ.

[0049] In the simulation environment, the diameter of the outer plane plate 1-4 of the balanced feeding section is set to 2.63λ~2.66λ; the diameter of the feeding cabin 3-1 is set to 0.65λ~0.68λ, and the height of the feeding cabin 3-1 is set to 0.44λ~0.46λ. Figure 4 The feed array 2-5 is composed of three cylinders placed sideways. The diameter of the first cylinder 4-1 is 0.05λ~0.09λ, and the length is 0.03λ~0.04λ; the diameter of the second cylinder 4-2 is 0.03λ~0.04λ, and the length is 0.08λ~0.1λ; the diameter of the third cylinder 4-3 is 0.06λ~0.1λ, and the length is 0.01λ~0.02λ; the distance between the center of the three cylinders and the bottom is 0.2λ~0.24λ; and the distance from the side wall is 0.002λ~0.003λ. It should be noted that the dimensions of the components not described in the present invention, such as the dimensions of the SMA connector, can be defined by oneself.

[0050] S120: In a simulation environment, obtain a frequency radiation direction and a gain curve of the antenna in a specified frequency band. Optionally, the specified frequency band is 1 GHz to 1.8 GHz.

[0051] S130. Within the size range, respectively optimize the sizes of the dielectric radiation section 1-1, the foam support section 1-2 and the balanced feeding section 1-3 so that the frequency radiation direction and the gain curve meet the set requirements.

[0052] The optimization sequence is to optimize the dielectric radiation section 1-1 first, and then control the radiation pattern inside the antenna by adjusting the bottom diameter of the different curved dielectric columns. After the dielectric radiation section 1-1 is finally optimized, A is 0.5, R is 0.045, the height of the first curved dielectric column 2-1 is 119mm, and the corresponding S1 is 198mm; the height of the second curved dielectric column 2-2 is 112mm, and the corresponding S2 is 398mm; the height of the third curved dielectric column 2-3 is 107mm, and the corresponding S3 is 597mm; the height of the fourth curved dielectric column 2-4 is 88mm, and the corresponding S4 is 790mm. The radiation pattern of the optimized antenna shows significant main lobe concentration, and the side lobes are also suppressed.

[0053] Next, based on the size of the above-mentioned dielectric radiation section 1-1, the balanced feed section 1-3 is optimized, and the geometric parameters of the feed array 2-5 are adjusted to achieve broadband working performance; the specific parameters are finally determined as follows: the diameter of the outer plane plate 1-4 of the balanced feed section is 790mm; the diameter of the feed cabin 3-1 is 197.96mm, and the height of the feed cabin 3-1 is 137.73mm. Each feed array 2-5 is composed of three cylinders placed on their sides, the diameter of the first cylinder 4-1 is 15mm and the length is 10.18mm; the diameter of the second cylinder 4-2 is 10.23mm and the length is 26.86mm; the diameter of the third cylinder 4-3 is 17.4mm and the length is 5.55mm. The geometric center distance of the three sections of the cylinders that make up the feed array 2-5 is 63.9mm from the bottom; the third cylinder is 7mm away from the side wall; the optimized balanced feed section 1-3 achieves broadband single-mode excitation.

[0054] Finally, the foam support section 1-2 between the dielectric radiation section 1-1 and the balanced feed section 1-3 of the antenna is simulated and adjusted to optimize the antenna radiation efficiency and gain. The height of the final optimized foam section is 160mm, the inner diameter is 198mm, and the outer diameter is 790mm; it ensures that the antenna radiation pattern and gain curve at the frequency meet the set requirements, that is, the antenna reaches a bandwidth of 1.8 times the frequency and the gain reaches 15dBi. The directional pattern results and gain results of the optimized antenna are attached. Figure 6 and attached Figure 7 . Figure 6The solid line is the 1 GHz radiation pattern, the dashed line is the 1.4 GHz radiation pattern, and the dotted line is the 1.8 GHz radiation pattern;

[0055] Figure 7 The curve of antenna gain changing with frequency from 1GHz to 1.8GHz. The antenna pattern has good symmetry and the gain is higher than 15dBi.

[0056] It should be noted that the terms used in the present invention are only for describing specific embodiments, rather than limiting the scope of the present application. As shown in the present specification, unless the context clearly indicates an exception, the words "one", "a", "a kind of" and / or "the" do not specifically refer to the singular, but may also include the plural. The terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method or device. In the absence of more restrictions, the elements defined by the sentence "include one..." do not exclude the presence of other identical elements in the process, method or device including the elements.

[0057] It should also be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. 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 an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A low-frequency, lightweight, high-gain antenna. It is characterized in that include: Dielectric radiation section, foam support section and balanced feed section; The dielectric radiation section is composed of a plurality of concentric curved dielectric columns with different heights, diameters and dielectric constants; the dielectric constants of the dielectric columns gradually decrease from the inside to the outside; the dielectric radiation section excites the antenna by a balanced feeding method and realizes dual polarization at the same time; The foam support section is used to support the dielectric radiation section so that the set distance condition is met between the dielectric radiation section and the balanced feeding section; The balanced feeding section provides a feeding signal for the antenna, and combined with the use of a 180° bridge, generates a potential difference on the symmetrical feeding array to achieve broadband single-mode excitation.

2. The low-frequency, lightweight, high-gain antenna according to claim 1, It is characterized in that The low-frequency, lightweight, high-gain antenna has a bandwidth of 1.8 times the frequency and a gain of 15dBi.

3. The low-frequency, lightweight, high-gain antenna according to claim 1, It is characterized in that The dielectric radiation section specifically includes a first curvilinear dielectric column, a second curvilinear dielectric column, a third curvilinear dielectric column and a fourth curvilinear dielectric column; The dielectric constant of the first curved dielectric column is 10.2, the dielectric constant of the second curved dielectric column is 9.2, the dielectric constant of the third curved dielectric column is 6.15, and the dielectric constant of the fourth curved dielectric column is 3.55; the heights of the four concentric curved dielectric columns decrease layer by layer from the inside to the outside; the thicknesses of the four concentric curved dielectric columns are the same.

4. The low-frequency, lightweight, high-gain antenna according to claim 1, It is characterized in that The foam support section is a hollow cylinder with a height of 160 mm, an inner diameter of 198 mm and an outer diameter of 790 mm.

5. The low-frequency, lightweight, high-gain antenna according to claim 1, It is characterized in that The balanced feeding section includes a feeding cabin, four feeding arrays and four coaxial cable connectors; the inner conductor of each coaxial cable connector extends into the feeding cabin and is connected to the feeding array; The other end of the coaxial cable connector is connected to an external 180° bridge to generate a potential difference on the symmetrical feeding arrays to achieve balanced feeding excitation. The four feeding arrays realize dual-polarization performance of the antenna.

6. The low-frequency, lightweight, high-gain antenna according to claim 5, It is characterized in that The diameter of the outer plane plate of the balanced feeding section is 790mm; the diameter of the feeding cabin is 197.96mm, and the height of the feeding cabin is 137.73mm.

7. The low-frequency, lightweight, high-gain antenna according to claim 5, It is characterized in that Each feed array is composed of three cylinders placed sideways. The diameter of the first cylinder is 15mm and the length is 10.18mm; the diameter of the second cylinder is 10.23mm and the length is 26.86mm; the diameter of the third cylinder is 17.4mm and the length is 5.55mm. The geometric center of the three cylinders that make up the feed array is 63.9 mm away from the bottom; the third cylinder is 7 mm away from the side wall.

8. The low-frequency, lightweight, high-gain antenna according to claim 2, It is characterized in that The outer wall curve equation of each of the curvilinear medium columns is: y = A*{exp[R*(x-Si)]-1}; Among them, A is the straightness of the curve, which is 0.5, R is the curvature of the curve, which is 0.045, and S i is the bottom diameter of the i-th curved medium column, x is the independent variable of the outer wall curve equation, and y is the dependent variable of the outer wall curve equation.

9. A design method for a low-frequency, lightweight, high-gain antenna. It is characterized in that include: Model the dielectric radiation section, foam support section and balanced feed section in the simulation environment, define the size range and the outer wall curve equation of each curved dielectric column; In the simulation environment, obtain the frequency radiation direction and gain curve of the antenna within the specified frequency band; Within the size range, the sizes of the dielectric radiation section, the foam support section and the balanced feeding section are optimized respectively so that the frequency radiation direction and the gain curve meet the set requirements.

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