Variable parameter short wave log periodic antenna

Abstract

This utility model discloses a variable-parameter shortwave log-periodic antenna, comprising a tower, the base of which is mounted on the ground via a tower foundation, a turntable at the top of the tower, a V-shaped support at the top of the turntable, and a truss at the top of the V-shaped support. A connecting cable supplies power to the antenna surface via an impedance transformer and a connecting line. The antenna surface includes 14 elements mounted on the truss. Compared with a fixed-parameter shortwave log-periodic antenna, the variable-parameter shortwave log-periodic antenna disclosed in this utility model does not require changes to the truss structure dimensions or the installation position of the elements on the truss. Only the element length needs to be adjusted to achieve bandwidth expansion, greatly reducing the complexity of structural design and product development cycle, lowering costs, and improving the modularity and versatility of the product structure.

Description

Technical Field

[0001] This utility model relates to the field of shortwave communication research, specifically to a shortwave log-periodic antenna that achieves bandwidth extension through innovative variable parameter design. Background Technology

[0002] Log-periodic antennas are widely used in shortwave communication, covering the entire shortwave band. The main design parameters of a typical log-periodic antenna include: , and .

[0003] The scaling factor for the antenna:

[0004]

[0005] In the above formula, such as Figure 1 As shown, , , These are the spacing between adjacent oscillators, the distance from an oscillator to the vertex, and the length of one arm of an oscillator, respectively. The total number of oscillators is... .

[0006] The antenna spacing factor represents the relationship between the element spacing and the element length.

[0007]

[0008] The included angle is 1 / 2 of the line connecting the ends of the oscillator.

[0009]

[0010] When frequency When the frequency changes continuously, the electrical characteristics of the antenna change periodically with the logarithm of the frequency, that is, at some discrete frequency points... , , , The electrical performance of the antennas is exactly the same across all frequencies, except for the frequency periods. , , ...the internal properties change with frequency, and the period of change of electrical properties is the logarithmic period of the frequency.

[0011] Most existing conventional log-periodic antenna designs use a single scaling factor. Spacing factor Half angle Some specially designed log-periodic antennas modify local aspects (such as the length of the long element), add circuitry to the element root, or add stubs to the element end to improve the voltage standing wave ratio (VSWR) or radiation characteristics at specific frequencies. These specially designed log-periodic antennas only change the antenna design parameters locally, while the main structure still follows the design principles of log-periodic antennas.

[0012] Due to the constraints of fixed parameters in log-periodic antennas, this type of conventional antenna requires changes to its main structure, such as altering the truss length or the position of the vibrator on the truss, when expanding its bandwidth. This design approach increases the complexity of the design, the product development cycle, and the cost in engineering implementation, while reducing the modularity and versatility of the product structure. Utility Model Content

[0013] The technical problem to be solved by this utility model is to provide a shortwave log-periodic antenna that achieves flexible bandwidth expansion through innovative design with variable parameters.

[0014] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0015] An improved shortwave log-periodic antenna with variable parameters includes a tower, the base of which is mounted on the ground via a tower foundation, a turntable at the top of the tower, a V-shaped support at the top of the turntable, and a truss at the top of the V-shaped support. A transfer cable supplies power to the antenna surface via an impedance transformer and a connecting line. The antenna surface includes 14 elements mounted on the truss, with single-arm lengths of the elements being: 12.71 m, 10.82 m, 9.20 m, 7.83 m, 6.67 m, 5.67 m, 4.83 m, 4.11 m, 3.50 m, 2.98 m, 2.53 m, 2.15 m, 1.83 m, and 1.56 m.

[0016] Furthermore, the antenna is 20m high, with a horizontal projection of 25.4m × 26.1m, and weighs 3.3 tons.

[0017] Furthermore, guy wires are installed between the tower body and the ground.

[0018] Furthermore, a central tower is installed on the truss, and a lightning rod is installed on the central tower.

[0019] Furthermore, the truss adopts a square steel structure with a cross section of 500mm×500mm, and the material is Q235B carbon structural steel. The main members of the truss are angle steel and the web members are round steel. Round steel is welded to the inside of the main members of each section.

[0020] Furthermore, a pull wire for the oscillator is installed between the truss and the oscillator.

[0021] Furthermore, the oscillator is made by splicing aluminum alloy tubes of different diameters and wall thicknesses through oscillator joints.

[0022] Furthermore, a plug is installed on the aluminum alloy tube at the end of the oscillator.

[0023] Furthermore, the oscillator root is mounted onto the truss via an oscillator mounting bracket assembly.

[0024] Furthermore, the vibrator is electrically connected to the bundle line via an aluminum alloy bushing, the vibrator's central shaft, and a bundle line jumper. Adjacent vibrators are electrically connected to the bundle line at crossover points, and the antenna's feed point is at the shortest vibrator end.

[0025] The beneficial effects of this utility model are:

[0026] The variable parameter shortwave log-periodic antenna disclosed in this utility model, compared with the fixed parameter shortwave log-periodic antenna, does not require changing the truss structure size and the installation position of the vibrator on the truss. The bandwidth can be expanded simply by adjusting the length of the vibrator, which greatly reduces the complexity of the structural design and the product development cycle, reduces the cost, and improves the modularity and versatility of the product structure. Attached Figure Description

[0027] Figure 1 This is a schematic diagram illustrating the working principle of a log-periodic antenna.

[0028] Figure 2 This is a schematic diagram of the overall structure of the variable parameter shortwave log-periodic antenna disclosed in this utility model;

[0029] Figure 3 This is a schematic diagram of the antenna surface structure;

[0030] Figure 4-1 This is a schematic diagram of the truss structure viewed from below;

[0031] Figure 4-2 This is a side view of the truss structure.

[0032] Figure 4-3 This is a top view of the truss structure.

[0033] Figure 5 This is a schematic diagram of the structure of oscillator No. 1;

[0034] Figure 6 This is a structural schematic diagram of the oscillator mounting bracket assembly;

[0035] Figure 7 This is a schematic diagram of the structure of the convergence line;

[0036] Figure 8 This is a comparison chart of voltage standing wave ratio (VSWR) curves.

[0037] Figure label:

[0038] 1—Iron tower, 2—Iron tower foundation, 3—Turntable, 4—V-shaped support, 5—Truss, 51—Main pole, 52—Web pole, 6—Transfer cable, 7—Impedance transformer, 8—Gathering line, 9—Antenna surface, 91—Vibrator, 911—φ90×4mm aluminum alloy tube, 912—φ80×4mm aluminum alloy tube, 913—φ70×3mm aluminum alloy tube, 914—φ45×2.5mm aluminum alloy tube, 915—Vibrator connector, 92—Vibrator guy wire, 10—Iron tower guy wire, 11—Middle tower, 12—Lightning rod. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model 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 present utility model and are not intended to limit the present utility model.

[0040] Example 1, such as Figure 2 As shown, this embodiment discloses a variable-parameter shortwave log-periodic antenna, including a tower 1. The base of the tower is mounted on the ground via a tower foundation 2. The top of the tower is a turntable 3, the top of the turntable is a V-shaped bracket 4, and the top of the V-shaped bracket is a truss 5. A connecting cable 6 supplies power to the antenna surface 9 via an impedance transformer 7 and a connecting line 8. The antenna surface includes fourteen vibrators 91 mounted on the truss, with single-arm lengths of the vibrators being: 12.71m, 10.82m, 9.20m, 7.83m, 6.67m, 5.67m, 4.83m, 4.11m, 3.50m, 2.98m, 2.53m, 2.15m, 1.83m, and 1.56m, respectively.

[0041] The functions of the main components of an antenna are as follows:

[0042] Oscillator: It converts alternating current into electromagnetic signals and radiates them out; it is the core component for realizing the function of an antenna.

[0043] The connecting line is the path through which alternating current is transmitted between the oscillator and the impedance transformer;

[0044] Impedance transformer: Enables impedance matching and balanced-to-unbalanced conversion between the antenna and the feed line;

[0045] Trusses: These secure electrical components such as oscillators, conductors, and impedance transformers, ensuring structural support.

[0046] Tower: Provides structural support for the entire antenna.

[0047] Antenna scaling factor =0.851, and the parameters satisfy the following unconventional relationship:

[0048]

[0049] Spacing factor It is a variable that changes with the position of the oscillator, i.e., a variable parameter. The values ​​of the variable parameter spacing factor are shown in the table below:

[0050]

[0051] The antenna uses parallel double lines with a spacing D = 0.1m and a diameter d = 0.008m. The impedance transformer ratio is 200Ω:50Ω. The antenna surface dimensions are 25.42m x 26.17m (horizontal x vertical), with a support height h = 20m and a weight of approximately 3.3 tons. See the table below for detailed antenna structural dimensions.

[0052]

[0053] This embodiment also includes a tower guy wire 10 between the tower body and the ground. A middle tower 11 is installed on the truss, and a lightning rod 12 is installed on the middle tower. Figure 4-1 , 4-2 As shown in Figure 4-3, the truss adopts a square steel structure with a cross-section of 500mm × 500mm, made of Q235B carbon structural steel. The main members 51 of the truss 5 are angle steel, and the web members 52 are round steel. Round steel is welded to the inside of the main members of each section to enhance the strength of the truss. Figure 3 As shown, a pull wire 92 for the oscillator is also installed between the truss and the oscillator.

[0054] The antenna surface's structural design fully considers its stress conditions, including the effects of its own weight and wind load. The vibrator is made of 6061 T6 aluminum alloy tubing. Depending on the design length and stress conditions, aluminum alloy tubing of different diameters and wall thicknesses is used, connected by bolts via vibrator joints 915. For example... Figure 5 As shown, taking the structural design of oscillator No. 1 as an example, it is spliced ​​together from aluminum alloy tubes with four cross sections: φ90×4mm911, φ80×4mm912, φ70×3mm913 and φ45×2.5mm914. A plug is installed on the aluminum alloy tube opening at the end of the oscillator to prevent water from entering the aluminum alloy tube.

[0055] The oscillator base is mounted to the truss via an oscillator mounting bracket assembly, such as... Figure 6 As shown, the main components of the oscillator mounting bracket assembly are made of insulating materials such as epoxy laminated glass cloth, polytetrafluoroethylene, and ceramics to ensure insulation between the oscillator and the truss. Figure 7 This is a schematic diagram of the structure of the convergence line.

[0056] The vibrator is electrically connected to the bundle line via an aluminum alloy bushing, the vibrator's central shaft, and a bundle line jumper. Adjacent vibrators are electrically connected to the bundle line at crossover points. The antenna's feed point is at the shortest vibrator end.

[0057] In summary, the main structure of a variable-parameter shortwave log-periodic antenna includes the antenna surface, transmission matching section, mechanical support section, and accessories. The antenna surface is the main functional module of the antenna, used to realize the antenna's electrical performance, and includes the dipole and dipole guy wire. The transmission matching section includes the busbar, impedance transformer, and adapter cable; the mechanical support section, as the main load-bearing part of the antenna, includes the tower foundation, tower, turntable, V-shaped bracket, truss, and central tower; the accessories include the tower guy wire and lightning rod.

[0058] Figure 8 The voltage standing wave ratio (VSWR) curves of the variable-parameter shortwave log-periodic antenna and the fixed-parameter log-periodic antenna in this embodiment are compared (calculated using EMSS's FEKO electromagnetic simulation software). As can be seen from the figure, under the requirement of VSWR < 2.0, compared with the fixed-parameter log-periodic antenna, the variable-parameter shortwave log-periodic antenna in this embodiment achieves bandwidth expansion in the 26MHz-30MHz frequency band, with a bandwidth increase of 20%.

Claims

1. A variable-parameter shortwave log-periodic antenna, characterized in that: The system includes an iron tower, the base of which is mounted on the ground via a tower foundation. The top of the tower is a turntable, the top of which is a V-shaped support, and the top of the V-shaped support is a truss. A transfer cable supplies power to the antenna surface via an impedance transformer and a connecting line. The antenna surface includes 14 elements mounted on the truss, with single-arm lengths of the elements being: 12.71m, 10.82m, 9.20m, 7.83m, 6.67m, 5.67m, 4.83m, 4.11m, 3.50m, 2.98m, 2.53m, 2.15m, 1.83m, and 1.56m.

2. The variable-parameter shortwave log-periodic antenna according to claim 1, characterized in that: The antenna is 20m high, with a horizontal projection of 25.4m × 26.1m, and weighs 3.3 tons.

3. The variable-parameter shortwave log-periodic antenna according to claim 1, characterized in that: Guy wires are installed between the tower body and the ground.

4. The variable-parameter shortwave log-periodic antenna according to claim 1, characterized in that: Install a central tower on the truss, and install a lightning rod on the central tower.

5. The variable-parameter shortwave log-periodic antenna according to claim 1, characterized in that: The truss adopts a square steel structure with a cross section of 500mm×500mm, and the material is Q235B carbon structural steel. The main members of the truss are angle steel and the web members are round steel. Round steel is welded to the inside of the main members of each section.

6. The variable-parameter shortwave log-periodic antenna according to claim 1, characterized in that: A pull wire is also installed between the truss and the vibrator.

7. The variable-parameter shortwave log-periodic antenna according to claim 1, characterized in that: The oscillator is made of aluminum alloy tubes of different diameters and wall thicknesses spliced ​​together through oscillator joints.

8. The variable parameter shortwave log-periodic antenna according to claim 7, characterized in that: Install a plug on the aluminum alloy tube at the end of the oscillator.

9. The variable-parameter shortwave log-periodic antenna according to claim 1, characterized in that: The oscillator is mounted to the truss at its base via an oscillator mounting bracket assembly.

10. The variable-parameter shortwave log-periodic antenna according to claim 1, characterized in that: The vibrator is electrically connected to the bundle line via an aluminum alloy bushing, the vibrator's central shaft, and a bundle line jumper. Adjacent vibrators are electrically connected to the bundle line at crossover points. The antenna's feed point is at the shortest vibrator end.

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