Very high frequency omnidirectional antenna array blind area optimization method based on directional antenna supplement

Abstract

The invention relates to the technical field of wireless communication, in particular to a very high frequency omnidirectional antenna array blind area optimization method based on directional antenna supplement, which comprises the following steps of: establishing a very high frequency omnidirectional antenna unit model, and executing free space simulation; constructing at least one directional antenna precise model; constructing a very high frequency reference omnidirectional antenna array model based on an erected base; and simulating the reference model, obtaining an initial radiation pattern, and identifying and recording the orientation and range of the communication blind area. According to the invention, the number and spacing of the directional antennas are optimized through parameterized scanning, the communication blind area of the very high frequency omnidirectional antenna array is accurately eliminated, and the communication reliability is improved; a complete reusable design process is established, the erection of a base model is simplified, and the simulation time and the engineering cost are reduced; a parameter interval in a limited space is defined, and the engineering operability is enhanced; a single / double directional antenna supplement scheme library is formed, different blind areas and resource scenes are adapted, and the practicability is high.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, specifically to a method for optimizing the blind zone of a VHF omnidirectional antenna array based on directional antenna supplementation. Background Technology

[0002] In wireless communication systems, a Very High Frequency (VHF, 30MHz-300MHz) antenna is an omnidirectional antenna array. Because VHF omnidirectional antenna arrays can achieve 360° horizontal radiation coverage, they are widely used in high-rise buildings, communication towers, and other installation scenarios, and are core equipment for civil aviation air-to-ground communication and urban emergency communication. Ideally, the horizontal radiation pattern of a VHF omnidirectional antenna array should be a regular circle with consistent radiation gain in all azimuth angles; however, in actual deployment, the following three factors can easily create communication blind spots:

[0003] Antenna structural deviations: Insufficient processing precision and assembly symmetry of the elements in an omnidirectional antenna array lead to uneven radiation field distribution;

[0004] Environmental interference: Towers, supports, surrounding buildings, terrain, etc., can cause electromagnetic wave reflection, scattering, and diffraction, distorting the radiation pattern;

[0005] Impact of base installation: Metal bases can interfere with electromagnetic radiation, and traditional designs make it difficult to quantify their impact on radiation characteristics.

[0006] To eliminate blind spots, existing technologies generally adopt the solution of "adding a directional antenna to compensate for gain". However, existing technologies have the following significant drawbacks in practical use:

[0007] Relying on experience and lacking quantitative guidance: The selection of the number of directional antennas and key parameters such as installation location rely entirely on the experience of engineers for estimation and trial and error. It is impossible to scientifically analyze the impact of parameters on radiation characteristics, resulting in low design efficiency and unstable blind spot elimination effect.

[0008] Challenges of Optimizing Limited Space: Space is limited in installation scenarios such as the top of iron towers and the rooftops of high-rise buildings. There is a lack of systematic solutions for how to coordinate the layout of omnidirectional and directional antennas in extremely small spaces to achieve "maximum coverage of blind spots with limited resources".

[0009] Lack of environmental impact assessment: The interference of the base on radiation characteristics was not systematically assessed, resulting in a large deviation between the simulation design and the actual deployment effect, and the practicality of the solution was insufficient. Summary of the Invention

[0010] The purpose of this invention is to provide a method for optimizing the blind zone of a VHF omnidirectional antenna array based on directional antenna supplementation, so as to solve the problems mentioned in the background art.

[0011] To achieve the above objectives, the present invention provides the following technical solution: a method for optimizing the blind zone of a VHF omnidirectional antenna array based on directional antenna supplementation, comprising the following steps:

[0012] S1. Establish a VHF omnidirectional antenna element model, perform free-space simulation, and obtain its radiation pattern, gain, and electric field strength characteristics. The electric field strength is calculated according to the formula... Calculations show that the directional function satisfies the formula. ;

[0013] in It is the electric field strength;

[0014] It is electric current;

[0015] This is the radial distance in spherical coordinates (the straight-line distance from a point in space to the origin of the coordinate system).

[0016] The zenith angle in spherical coordinates is the angle between the line connecting this point and the origin and the positive z-axis.

[0017] Azimuth angle in spherical coordinate system (the angle between the line connecting the projection of the point onto the xy plane and the origin and the positive x-axis).

[0018] It is a unit vector in spherical coordinates;

[0019] The phase shift constant;

[0020] S2. Construct a precise model of at least one directional antenna and obtain its radiation pattern, front-to-back ratio, gain, and beamwidth characteristics in free space through simulation.

[0021] S3. Construct a VHF reference omnidirectional antenna array model based on the erected base, and set the physical dimensions of the array elements and the relative positions (including spacing and azimuth) of each array element according to the working wavelength of the VHF signal; simulate the reference model, obtain the initial radiation pattern, and identify and record the azimuth and range of the communication blind zone;

[0022] S4. Add a directional antenna to the reference omnidirectional antenna array model in step S3 to construct at least two blind zone elimination schemes; use electromagnetic simulation software to perform full-wave simulation (directly solve Maxwell's equations, automatically consider mutual coupling and structural effects), compare the radiation patterns of each scheme with the reference model, evaluate the blind zone elimination effect, and select the better supplementary scheme.

[0023] S5. For the better supplementary schemes selected in step S4, systematically change the horizontal and vertical distances between the omnidirectional antenna and the directional antenna to form multiple distance combinations and simulate them separately; analyze the influence of distance changes on the radiation pattern (including the blind zone improvement effect and maximum gain) and determine the optimal range of parameter values;

[0024] S6. Place the optimized antenna array model from step S5 onto the erection base for simulation and analyze the influence of the base on the radiation characteristics. By comparing the simulations, it is determined that the influence of the tower height is negligible, and its main influence is determined by the base structure at the bottom of the tower. The complex tower structure is simplified into an equivalent base model.

[0025] S7. Integrate the omnidirectional antenna array, the number of directional antennas selected in step S4, the optimized distance parameters determined in step S5, and the simplified base model in step S6 to construct a comprehensive simulation model that approximates the actual scenario of a VHF station; simulate the model to verify the blind zone elimination effect and overall radiation characteristics, evaluate the engineering feasibility, and output the optimal configuration scheme.

[0026] Preferably, the VHF omnidirectional antenna in step S1 is a symmetrical dipole antenna with a total length of 1250 mm, a radius of 2.5 mm, a VSWR of <1.4, and an impedance of 73.1 Ω.

[0027] The VHF omnidirectional antenna operates in the frequency band of 118MHz-137MHz.

[0028] Preferably, in step S2, the directional antenna is a two-element symmetrical dipole antenna array with a reflector mesh, and each element of the two-element symmetrical dipole antenna array is a symmetrical dipole antenna, and the element parameters are consistent with the parameters of the VHF omnidirectional antenna (symmetrical dipole antenna) in step S1.

[0029] The reflector is located behind the binary symmetrical dipole antenna array. The distance between the reflector and the center of symmetry of the binary symmetrical dipole antenna array (the midpoint of the line connecting the centers of the two array elements) is λ / 4 of the VHF signal wavelength, where λ is the VHF signal wavelength.

[0030] Preferably, in step S3:

[0031] The base includes a metal base and a non-metal base;

[0032] The omnidirectional antenna array consists of three VHF omnidirectional antennas from step S1; the three omnidirectional antenna elements are distributed at a 120° angle with respect to the array's geometric center (origin), and the distance between each omnidirectional antenna element and the origin is 3825mm.

[0033] Preferably, the blind spot elimination scheme in step S4 includes:

[0034] Single-directional antenna supplement scheme: A directional antenna is added near the blind zone around the reference omnidirectional antenna array, so that the maximum radiation direction of the directional antenna is aligned with the center of the blind zone; the distance between the symmetrical center point of the directional antenna (the midpoint of the line connecting the centers of the two elements of the two-element symmetrical dipole antenna array) and the origin of the reference omnidirectional antenna array is 3200mm; the array elements of the directional antenna and the array elements of the omnidirectional antenna are both located in the XOY plane, and the distance between them is 625mm.

[0035] Preferably, the blind spot elimination scheme in step S4 includes:

[0036] Dual-directional antenna supplementation scheme: The directional antenna in the single-directional antenna supplementation scheme is rotated 120° around the z-axis to form two directional antennas. The two directional antennas are respectively oriented towards different communication blind spots located in step S3, or they are oriented together towards the same wide-area communication blind spot.

[0037] Preferably, in step S5, the horizontal distance ranges from 0.1λ to 0.5λ, and the adjustment step size for the horizontal distance is 0.1λ; the vertical distance ranges from 0λ (VHF omnidirectional antenna and directional antenna are coplanar) to 1.0λ, and the adjustment step size for the vertical distance is 0.25λ.

[0038] Preferably, in step S6, the bottom base model structure is a regular metal circular surface with a diameter of not less than 3000 mm, and in steps S4, S5, S6 and S7, the electromagnetic simulation software is HFSS or CST.

[0039] Compared with the prior art, the beneficial effects of the present invention are:

[0040] This invention establishes a systematic parametric design process by establishing basic models of VHF omnidirectional and directional antennas and obtaining their radiation characteristics, constructing a reference omnidirectional antenna array model to locate blind spots, designing and simulating single / dual directional antenna supplementary schemes, performing parametric scanning optimization of antenna layout (horizontal / vertical distance), evaluating the impact of the mounting base and establishing a simplified model of the bottom base, and comprehensively modeling and verifying the feasibility of the final scheme. This solves the problems of existing technologies relying on experience, difficulty in optimizing within limited space, and insufficient environmental impact assessment. It can accurately eliminate blind spots, improve communication reliability, increase design efficiency, reduce costs, and enhance the applicability and flexibility of the scheme in different scenarios, making it suitable for antenna array optimization in VHF communication stations. Attached Figure Description

[0041] Figure 1 This is a flowchart illustrating the overall structure of the VHF omnidirectional antenna array blind zone optimization method based on directional antenna supplementation of the present invention.

[0042] Figure 2This is a schematic diagram of a VHF omnidirectional antenna model, illustrating the VHF omnidirectional antenna model of the VHF omnidirectional antenna array blind zone optimization method based on directional antenna supplementation according to the present invention.

[0043] Figure 3 This is a schematic diagram of the three-dimensional directional gain of a VHF omnidirectional antenna, illustrating the VHF omnidirectional antenna's blind zone optimization method based on directional antenna supplementation according to the present invention.

[0044] Figure 4 This is a schematic diagram of the directional antenna model for the VHF omnidirectional antenna array blind zone optimization method based on directional antenna supplementation according to the present invention.

[0045] Figure 5 This is a schematic diagram of the three-dimensional directional gain of the directional antenna in the VHF omnidirectional antenna array blind zone optimization method based on directional antenna supplementation according to the present invention.

[0046] Figure 6 This is a schematic diagram of the layout of the omnidirectional antenna array, which is based on the method for optimizing the blind zone of a VHF omnidirectional antenna array with directional antenna supplementation according to the present invention.

[0047] Figure 7 This is a schematic diagram of the three-dimensional radiation pattern, front view and top view gain of the omnidirectional antenna array, based on the VHF omnidirectional antenna array blind zone optimization method of the present invention with directional antenna supplementation.

[0048] Figure 8 This is a schematic diagram of the single directional antenna supplementation scheme modeling of the VHF omnidirectional antenna array blind zone optimization method based on directional antenna supplementation according to the present invention.

[0049] Figure 9 This is a schematic diagram of the three-dimensional radiation pattern and top-view gain of the single directional antenna supplementation scheme of the VHF omnidirectional antenna array blind zone optimization method based on directional antenna supplementation of the present invention;

[0050] Figure 10 This is a schematic diagram of the dual-directional antenna supplementation scheme for the VHF omnidirectional antenna array blind zone optimization method based on directional antenna supplementation according to the present invention.

[0051] Figure 11 This invention presents a three-dimensional radiation pattern front view and top view gain schematic diagram of the dual directional antenna supplementation scheme for the VHF omnidirectional antenna array blind zone optimization method based on directional antenna supplementation.

[0052] Figure 12 This is a schematic diagram of a VHF omnidirectional antenna array placed on a mounting base, based on the present invention's method for optimizing the blind zone of a VHF omnidirectional antenna array with directional antenna supplementation.

[0053] Figure 13 This is a schematic diagram of the three-dimensional directional gain of the omnidirectional antenna placed on the mounting base, based on the method for optimizing the blind zone of a VHF omnidirectional antenna array with the addition of a directional antenna according to the present invention. Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] Please see Figure 1-13 This invention provides a technical solution: a method for optimizing the blind zone of a VHF omnidirectional antenna array based on directional antenna supplementation, comprising the following steps:

[0056] S1. Establish a VHF omnidirectional antenna model and obtain its basic radiation characteristics.

[0057] First, in electromagnetic simulation software, a VHF omnidirectional antenna element model operating in the 118MHz-137MHz civil aviation VHF band is established, such as... Figure 2 The VHF omnidirectional antenna shown in this embodiment is a symmetrical dipole antenna. In this embodiment, the total length of the symmetrical dipole antenna is 1250 mm, the radius is 2.5 mm, the VSWR is <1.4, and the impedance is 73.1 Ω. With correct material properties, excitation ports, and boundary conditions set, free-space simulation is performed to obtain its radiation pattern, gain characteristics, and electric field strength characteristics. The electric field strength is calculated according to the formula... calculate, For the directional function to satisfy ;

[0058] in It is the electric field strength;

[0059] It is electric current;

[0060] This is the radial distance in spherical coordinates, i.e., the straight-line distance from a point in space to the origin of the coordinate system.

[0061] The zenith angle in the spherical coordinate system is the angle between the line connecting the point to the origin and the positive z-axis.

[0062] The azimuth angle in spherical coordinates is the angle between the line connecting the projection of the point onto the xy plane and the origin and the positive x-axis.

[0063] It is a unit vector in spherical coordinates;

[0064] The phase shift constant;

[0065] After simulation, key radiation characteristic parameters such as the two-dimensional / three-dimensional radiation pattern, gain, and input impedance of the omnidirectional antenna element are extracted and recorded. The model established and the data obtained in this step will serve as a benchmark for subsequent array design and performance comparison. Figure 3 The image shows the three-dimensional directional gain diagram of a VHF omnidirectional antenna.

[0066] S2. Establish a directional antenna model and obtain its basic radiation characteristics.

[0067] Similarly, in the electromagnetic simulation software, at least one accurate model of a directional antenna element that can be used for blind spot filling is constructed. In this example, the directional antenna consists of a binary antenna array and a reflector. The binary antenna array is composed of two elements, each of which is a symmetrical dipole antenna. Each element of the binary symmetrical dipole antenna array is a symmetrical dipole antenna, and the element parameters are consistent with the parameters of the VHF omnidirectional antenna (symmetrical dipole antenna) in step S1. The antenna reflects the radiation radiated towards the reflector, so the directional antenna has a particularly strong radiation gain in a specific direction, while the radiation gain in other directions is smaller. The size and spacing of the reflector are adjusted so that its maximum radiation direction is aligned with the expected blind spot filling location. The structural layout of the directional antenna is as follows: Figure 4 As shown, its three-dimensional directional gain is as follows Figure 5 As shown, the radiation pattern, front-to-back ratio, gain, and beamwidth characteristics in free space are obtained through simulation, laying the foundation for the design of subsequent improvement schemes;

[0068] The reflector is located behind the binary symmetrical dipole antenna array. The distance between the reflector and the center of symmetry of the binary symmetrical dipole antenna array (the midpoint of the line connecting the centers of the two array elements) is λ / 4 of the wavelength of the VHF signal, where λ is the wavelength of the VHF signal.

[0069] S3. Establish a reference omnidirectional antenna array model and locate communication blind spots.

[0070] Based on the omnidirectional antenna element established in step one, a VHF omnidirectional antenna array model composed of several omnidirectional antennas based on different mounting bases is constructed as a reference antenna array for performance evaluation. In this embodiment, the reference antenna array is composed of three omnidirectional antenna elements arranged at a specific interval (e.g., an integer multiple or a specific fractional multiple of the wavelength). The physical size of the array elements and the relative position of each array element are set according to the working wavelength of the VHF signal. The reference model is simulated to obtain its initial radiation pattern and to identify and record the location and range of the communication blind zone.

[0071] In terms of the material of the base, it mainly includes metals and non-metals. Metal bases have a significant impact on the radiation performance of the antenna array; different structural layouts of metal bases result in very different radiation patterns for the antenna array. Therefore, the structural layout of the metal base must be considered when building an antenna array model.

[0072] For a reference omnidirectional antenna array, the physical dimensions of each antenna element and the relative positions of each element (including specific spacing and azimuth) can be set according to the operating wavelength.

[0073] In this embodiment, the omnidirectional antenna array consists of three VHF omnidirectional antennas from step S1, such as... Figure 6 Layout diagram and Figure 7 The front and top views of the 3D radiation pattern are shown. Three omnidirectional antenna elements are distributed at a 120° angle with respect to the array's geometric center (origin). The distance between each omnidirectional antenna element and the origin is 3825 mm. The overall radiation pattern is obtained. By analyzing this pattern, azimuth regions where the gain is lower than the communication requirement threshold are identified. These regions are the "communication blind spots" that need to be eliminated, and the azimuth, depth, and width of the blind spots are recorded.

[0074] S4. Design and simulate various directional antennas to improve omnidirectional antenna arrays.

[0075] In step S3, a directional antenna is added to the reference antenna array model to construct at least two blind zone elimination schemes. Full-wave simulation verification is performed using electromagnetic simulation software. The resulting array antenna pattern is used to build the entire heterogeneous antenna array into a complete model, and full-wave simulation is performed using electromagnetic simulation software (such as HFSS, CST). This method directly solves Maxwell's equations, automatically considering all mutual coupling and structural effects, and the results are closest to the actual situation. After simulation, the radiation patterns of each scheme are compared and analyzed with the reference model to evaluate the blind zone elimination effect of different numbers of additions and to select the optimal addition scheme.

[0076] Elimination methods include:

[0077] Single-directional antenna supplementation scheme: A directional antenna is added near the blind zone around the perimeter of the reference omnidirectional antenna array, ensuring that the maximum radiation direction of the directional antenna is aligned with the center of the blind zone; for example... Figure 8 As shown, with the center point as the origin, one element of the omnidirectional antenna array is placed at a distance d1 (3825 mm) from the origin. The directional antenna is placed in the negative X-axis direction (the opposite direction of the green coordinate axis in the figure). The midpoint of the line connecting the centers of the two symmetrical dipole antennas can be called the center of symmetry of the directional antenna, which is d2 (3200 mm) from the origin. The centers of the symmetrical dipole antennas and the center of symmetry of the directional antenna are both in the XOY plane, and the distance between them is defined as d3, with a length of 625 mm, which is λ / 4 of the distance. The center of symmetry of the directional antenna is also λ / 4 of the distance from the reflector. The remaining two symmetrical dipole antennas are obtained by rotating the symmetrical dipole antennas by 120° and 240° around the Z-axis, respectively. Figure 9 It is the three-dimensional radiation pattern of the single directional antenna supplementation scheme;

[0078] Dual-directional antenna supplementation scheme: If the blind zone is wide or there are multiple main blind zones, two directional antennas are added at the corresponding locations, and their orientation is adjusted to cover different blind zones respectively or to cover the same wide-area blind zone together. Specifically, the directional antenna located in the negative X-axis direction is rotated 120° around the Z-axis to create another directional antenna, forming the antenna array model of the second scheme. The two directional antennas are oriented towards the different communication blind zones located in step S3, or together towards the same wide-area communication blind zone, and simulation calculations are performed. After the simulation is completed, the radiation patterns of each supplementation scheme are compared with the reference radiation pattern in step three, focusing on observing the degree of gain improvement in the blind zone direction and evaluating the effectiveness of different supplementation numbers. Figure 10 This is a modeling illustration of Scheme 2. Figure 11 It is the result of simulation.

[0079] S5. Perform parametric scanning optimization of antenna layout.

[0080] For the optimal supplementary scheme selected in step S4, further research is conducted on the optimization of the relative parameterized layout between antennas. This is achieved by systematically changing the horizontal and vertical distances between the added directional antennas and the reference point of the omnidirectional antenna array (usually the array's geometric center), forming multiple distance combinations and simulating them separately. In this embodiment, the horizontal distance is within the range of 0.1λ to 0.5λ, with a step value of 0.1λ. The vertical distance is within the range of 0λ (coplanar) to 1.0λ, with a step value of 0.25λ. A model is established and simulated for each distance combination. By comparing the radiation patterns of all simulation results, the influence of changes in horizontal and vertical distances on the blind zone filling effect, maximum gain, and radiation pattern shape is analyzed. This determines a set or range of optimal distance parameters, achieving the best balance between blind zone elimination and overall radiation pattern smoothness, thus determining the optimal parameter value range.

[0081] S6. Environmental impact model for evaluating the installation of the base.

[0082] The optimized antenna array model from step S5 is simulated on the erection base to analyze the influence of the base on the radiation characteristics. When the omnidirectional antenna array is placed on a metal tower, comparative simulations show that: First, different tower heights have a negligible impact on the antenna radiation characteristics; Second, the influence on the omnidirectional antenna array mainly comes from the structural layout of the horizontal metal base, thus determining that the tower height has a negligible impact, and its main influence is determined by the base structure of the tower. Therefore, this invention simplifies the complex tower structure into an equivalent base model, thereby significantly improving modeling and simulation efficiency while ensuring the accuracy of the results. The base model structure is a regular metal circular surface, such as... Figure 12As shown, the diameter of the regular metal circular surface is not less than 3000mm, and the electromagnetic simulation software in steps S4, S5, S6 and S7 is HFSS or CST.

[0083] S7. Comprehensive Modeling and Feasibility Verification of the Final Solution

[0084] By integrating the omnidirectional antenna array, the optimal number of directional antennas selected in step S4, the optimized distance parameters determined in step S5, and the simplified base model in step S6, a comprehensive simulation model closely resembling the actual scenario of a VHF station is constructed (including the base setup, the omnidirectional antenna array, and the optimal number and layout of directional antennas). Simulation of this model is performed, and its radiation pattern is analyzed, such as... Figure 13 As shown, it is confirmed that the communication blind zone has been effectively eliminated and the overall radiation characteristics meet the design specifications. The advantages and disadvantages and engineering feasibility of the final scheme are evaluated, and the optimal configuration scheme is output. The output of this step is an optimal configuration scheme of VHF antenna array that has been fully simulated and verified for a specific deployment environment. This scheme clarifies the type, quantity, spatial layout of directional antennas and the accurate modeling method for dealing with environmental impacts.

[0085] Through the systematic execution of the above steps, this invention can output an optimal configuration scheme for a VHF antenna array that has been fully simulated and verified for a specific deployment environment. This method clearly specifies the number of directional antennas, spatial layout, and modeling method for dealing with environmental impacts.

[0086] The present invention can achieve the following advantages

[0087] In terms of performance and reliability: This invention achieves precise and optimized blind zone elimination through systematic parameter scanning (number of directional antennas, horizontal distance, and vertical distance), completely changing the trial-and-error method that relies on engineering experience. It can accurately determine the optimal antenna configuration for eliminating specific blind zones, significantly improving the reliability and signal quality of communication links, and constructing a complete design closed loop from element analysis and parameter optimization to real-world scenario verification. The method of this invention starts with the analysis of element antenna characteristics, gradually delving into array optimization and environmental factor assessment, and finally verifying it in a near-realistic integrated model, forming a rigorous and reusable antenna array design optimization process, ensuring the scientific validity and feasibility of the solution.

[0088] Regarding engineering efficiency and cost: This invention establishes a complete and reusable simulation design process, significantly improving design efficiency and reducing development and time costs. A simplified model of key environmental factors is proposed, greatly enhancing simulation efficiency. In simulation modeling, not only the antenna itself is considered, but the influence of the metal support tower is also analyzed in detail. A key finding is that the tower height has a negligible impact, and can be simplified to consider only its base structure. This greatly simplifies the model complexity, improves simulation efficiency, and ensures that the results accurately reflect the radiation characteristics in the actual deployment environment, making the design scheme more practically applicable in engineering.

[0089] In terms of engineering applicability and operability: This invention provides clear engineering guidance for space-constrained scenarios. For example, in situations where the space on the top floor of the base is strictly limited, this invention, through parametric research, abandons the traditional trial-and-error approach. Its core lies in establishing a complete simulation analysis process to systematically study and quantify the influence of key parameters such as the number of directional antennas and their horizontal and vertical distances to omnidirectional antennas on the overall antenna array radiation pattern. This provides a scientific basis for finding the optimal configuration under specific spatial constraints. This allows engineers to quickly select the most effective and feasible configuration based on the available space on site, making it highly operable and practical.

[0090] The invention enhances the universality and flexibility of the solution: Instead of providing a single, rigid solution, it clarifies the improvement effect and applicable scenarios of different solutions on radiation gain by comparing the simulation results of various solutions such as "single directional antenna supplementation" and "dual directional antenna supplementation". This forms a "solution library" that can be flexibly selected according to the actual blind zone situation and resource conditions. The method can be selected according to the actual severity of the blind zone, resource budget and space conditions, thus enhancing its adaptability in different application scenarios.

[0091] 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, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0092] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for optimizing the blind zone of a VHF omnidirectional antenna array based on directional antenna supplementation, characterized in that: Includes the following steps: S1. Establish a VHF omnidirectional antenna element model, perform free-space simulation, and obtain its radiation pattern, gain, and electric field strength characteristics. The electric field strength is calculated according to the formula... Calculations show that the directional function satisfies the formula. ; in It is the electric field strength; It is electric current; The radial distance in spherical coordinates; The zenith angle in spherical coordinates; Azimuth in spherical coordinate system; It is a unit vector in spherical coordinates; The phase shift constant; S2. Construct a precise model of at least one directional antenna and obtain its radiation pattern, front-to-back ratio, gain, and beamwidth characteristics in free space through simulation. S3. Construct a VHF reference omnidirectional antenna array model based on the erected base; simulate the reference model, obtain the initial radiation pattern, and identify and record the location and range of the communication blind zone; S4. Add a directional antenna to the reference omnidirectional antenna array model in step S3 to construct at least two blind zone elimination schemes; use electromagnetic simulation software to perform full-wave simulation and select the better supplementary scheme; S5. For the better supplementary scheme selected in step S4, change the horizontal and vertical distances between the omnidirectional antenna and the directional antenna, and determine the range of parameter optimization values. S6. Place the optimized antenna array model from step S5 onto the erection base for simulation and analyze the influence of the base on the radiation characteristics; ignore the tower height and simplify the complex tower structure into an equivalent bottom base model. S7. Integrate the omnidirectional antenna array, the number of directional antennas selected in step S4, the optimized distance parameters determined in step S5, and the simplified base model in step S6 to construct a comprehensive simulation model that approximates the actual scenario of a VHF station; simulate the model to verify the blind zone elimination effect and overall radiation characteristics, evaluate the engineering feasibility, and output the optimal configuration scheme.

2. The method for optimizing the blind zone of a VHF omnidirectional antenna array based on directional antenna supplementation according to claim 1, characterized in that: In step S1, the VHF omnidirectional antenna is a symmetrical dipole antenna with a total length of 1250 mm, a radius of 2.5 mm, a VSWR of <1.4, and an impedance of 73.1 Ω. The VHF omnidirectional antenna operates in the frequency band of 118MHz-137MHz.

3. The method for optimizing the blind zone of a VHF omnidirectional antenna array based on directional antenna supplementation according to claim 2, characterized in that: In step S2, the directional antenna is a two-element symmetrical dipole antenna array with a reflector mesh. Each element of the two-element symmetrical dipole antenna array is a symmetrical dipole antenna, and the array element parameters are consistent with the parameters of the VHF omnidirectional antenna in step S1. The reflector is located behind the binary symmetrical dipole antenna array. The distance between the reflector and the center of symmetry of the binary symmetrical dipole antenna array is λ / 4 of the wavelength of the VHF signal, where λ is the wavelength of the VHF signal.

4. The method for optimizing the blind zone of a VHF omnidirectional antenna array based on directional antenna supplementation according to claim 3, characterized in that: In step S3: The base includes a metal base and a non-metal base; The omnidirectional antenna array consists of three very high frequency omnidirectional antennas from step S1; the three omnidirectional antenna elements are distributed at a 120° angle with respect to the array's geometric center.

5. The method for optimizing the blind zone of a VHF omnidirectional antenna array based on directional antenna supplementation according to claim 4, characterized in that: The blind spot elimination scheme in step S4 includes: Single directional antenna supplementation scheme: Add a directional antenna near the blind zone around the reference omnidirectional antenna array, so that the maximum radiation direction of the directional antenna is aligned with the center of the blind zone.

6. The method for optimizing the blind zone of a VHF omnidirectional antenna array based on directional antenna supplementation according to claim 5, characterized in that: The blind spot elimination scheme in step S4 includes: Dual-directional antenna supplementation scheme: The directional antenna in the single-directional antenna supplementation scheme is rotated 120° around the z-axis to form two directional antennas. The two directional antennas are respectively oriented towards different communication blind spots located in step S3, or they are oriented together towards the same wide-area communication blind spot.

7. The method for optimizing the blind zone of a VHF omnidirectional antenna array based on directional antenna supplementation according to claim 6, characterized in that: In step S5, the horizontal distance ranges from 0.1λ to 0.5λ, and the adjustment step size is 0.1λ; the vertical distance ranges from 0λ to 1.0λ, and the adjustment step size is 0.25λ.

8. The method for optimizing the blind zone of a VHF omnidirectional antenna array based on directional antenna supplementation according to claim 7, characterized in that: In step S6, the base model structure is a regular metal circular surface with a diameter of not less than 3000 mm. In steps S4, S5, S6 and S7, the electromagnetic simulation software is HFSS or CST.

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