Log-periodic antenna linear array design method considering sidelobe level and application thereof

Abstract

The application discloses a log-periodic antenna design method considering sidelobe level, and comprises the following steps: obtaining a normalized direction function of a main lobe direction of a uniform linear array composed of a plurality of antenna units, which is influenced by a beam scanning width of the uniform linear array; obtaining a corresponding relationship between a maximum sidelobe level and the beam scanning width, and obtaining a beam width factor corresponding to a target sidelobe level according to the corresponding relationship; determining a proportional factor and a spacing factor of a corresponding antenna unit according to the beam width factor; determining an antenna array gain, determining a number of the antenna units in the uniform linear array according to the antenna array gain; determining a lowest working frequency of the uniform linear array according to the normalized direction function, and calculating a dipole parameter of the corresponding antenna unit to complete the design of the linear array. The method can solve the problem that the traditional antenna array controls the sidelobe level by changing the spacing, the feeding amplitude and the phase of the antenna unit, thereby increasing the complexity and the cost of the feeding.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a method for designing a log-periodic antenna linear array considering sidelobe levels, a device for designing a log-periodic antenna linear array considering sidelobe levels, an electronic device, and a computer-readable storage medium. Background Technology

[0002] Phased array antennas have always been a hot topic in antenna research. They achieve beam scanning by changing the feed phase of antenna elements and are widely used in radio systems. As the beam scanning angle increases, the maximum sidelobe level also increases. Excessive sidelobe levels can introduce false alarms from other directions for radar and interfere with communication targets in other directions. Therefore, effective control of sidelobe levels is crucial when designing phased array antennas.

[0003] Conventional methods for controlling sidelobe levels typically include the following: (1) changing the spacing between antenna elements, i.e., non-equal spacing array; (2) changing the feed amplitude of antenna elements, using non-equal amplitude feed; (3) changing the feed phase of antenna elements, using non-linear phase difference; and (4) any combination of the above three methods. All of the above methods can effectively suppress the sidelobe level of the antenna array, but most of them require a large amount of computation using intelligent optimization algorithms (genetic algorithms, particle swarm algorithms, etc.), and these methods increase the complexity and cost of the antenna array design (for example, non-equal amplitude and non-linear phase difference methods will increase amplitude control devices and phase control devices, etc.). Therefore, proposing an effective method to suppress sidelobe levels without adding additional control devices and computational complexity is an urgent problem to be solved. Summary of the Invention

[0004] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a design method for a log-periodic linear array antenna with controllable sidelobe level. This method can solve the problem that traditional antenna arrays control the sidelobe level by changing the spacing of antenna elements, the amplitude of the feed, and the phase, which leads to increased feed complexity and cost.

[0005] On one hand, the first embodiment of the present invention provides a design method for a log-periodic antenna linear array considering sidelobe levels, comprising: obtaining a normalized direction function of the main lobe direction of a uniform linear array composed of several log-periodic dipole antenna elements, which is affected by the beam scanning width of the antenna elements themselves; obtaining the correspondence between the maximum sidelobe level and the beam scanning width according to the normalized direction function, and obtaining the beam width factor corresponding to the target sidelobe level according to the correspondence; determining the scaling factor and spacing factor of the corresponding antenna elements according to the beam width factor; determining the antenna array gain according to the scaling factor and the spacing factor, so as to determine the number of antenna elements in the uniform linear array according to the antenna array gain; and determining the minimum operating frequency of the uniform linear array according to the normalized direction function, and calculating the oscillator parameters of the corresponding antenna elements according to the maximum operating frequency, the scaling factor and the spacing factor, thereby completing the linear array design.

[0006] In one embodiment of the present invention, the normalized direction function is: ;in, For the number of antenna elements, , Defined as beamwidth factor; where, d is the wave constant, and d is the spacing between antenna elements. The angle between the main lobe and the normal, The direction of the main lobe.

[0007] In one embodiment of the present invention, obtaining the correspondence between the maximum sidelobe level and the beamwidth factor based on the normalized direction function includes: expressing the sidelobe level as: ;in, Indicates the direction of the main lobe. Indicates the angle of the grid lobe.

[0008] In one embodiment of the present invention, obtaining the beamwidth factor corresponding to the target sidelobe level according to the correspondence includes: calculating the beamwidth factor as follows: .

[0009] In one embodiment of the present invention, determining the number of antenna elements in the uniform linear array based on the antenna array gain includes: expressing the antenna array gain as: The number of antenna elements is calculated in this way. ;in, For antenna element gain in free space, This represents the image gain of the antenna element.

[0010] In one embodiment of the present invention, determining the minimum operating frequency of the uniform linear array based on the normalized direction function includes: obtaining, based on the normalized direction function, a range of antenna element spacing in which the uniform linear array does not exhibit grating lobes and the antenna elements do not overlap; determining the corresponding beam scanning bandwidth based on the antenna element spacing range, so as to determine the minimum operating frequency based on the beam scanning bandwidth and the maximum operating frequency.

[0011] In one embodiment of the present invention, the calculation of the oscillator parameters corresponding to the antenna element includes: calculating the number of oscillators based on the highest operating frequency and the lowest operating frequency; calculating the length of the longest oscillator and the length of the shortest oscillator based on the scaling factor and the spacing factor; and calculating the spacing between each adjacent oscillator based on antenna theory.

[0012] On the other hand, this invention proposes a design device for a log-periodic antenna linear array considering sidelobe levels, comprising: a normalized direction function acquisition module, used to acquire a normalized direction function of the main lobe direction of a uniform linear array composed of several log-periodic dipole antenna elements, which is affected by the beam scanning width of the antenna elements themselves; a beamwidth factor acquisition module, used to obtain the correspondence between the maximum sidelobe level and the beam scanning width according to the normalized direction function, and to obtain the beamwidth factor corresponding to the target sidelobe level according to the correspondence; a scaling / spacing factor determination module, used to determine the scaling factor and spacing factor of the corresponding antenna elements according to the beamwidth factor; an antenna element quantity determination module, used to determine the antenna array gain according to the scaling factor and the spacing factor, so as to determine the number of antenna elements in the uniform linear array according to the antenna array gain; and an element parameter calculation module, used to determine the minimum operating frequency of the uniform linear array according to the normalized direction function, and to calculate the element parameters of the corresponding antenna elements according to the maximum operating frequency, the scaling factor and the spacing factor, thereby completing the linear array design.

[0013] In another aspect, embodiments of the present invention provide an electronic device, comprising: a memory and one or more processors connected to the memory, the memory storing a computer program, and the processors executing the computer program to implement the log-periodic antenna design method considering sidelobe levels as described in any of the above embodiments.

[0014] In another aspect, embodiments of the present invention provide a computer-readable storage medium storing computer-executable instructions for performing a log-periodic antenna design method considering sidelobe levels as described in any of the above embodiments.

[0015] As can be seen from the above, the solution conceived by this invention, compared with the prior art, can have one or more of the following beneficial effects:

[0016] (1) By analyzing the relationship between the sidelobe level of the antenna element and the beam scanning bandwidth, the required sidelobe level can be achieved by controlling the beam scanning bandwidth. The beam scanning bandwidth can be achieved by designing the structural parameters of the log-periodic dipole antenna linear array, thus avoiding the need for additional control devices and computational complexity.

[0017] (2) By simultaneously analyzing and considering the conditions for generating grating lobes when antenna elements are arrayed and the influence of different antenna elements on the generation of grating lobes, the antenna element spacing that satisfies the condition of not generating grating lobes can be calculated more accurately, which can effectively avoid the main lobe shift and the occurrence of grating lobes.

[0018] (3) By considering the relationship between different antenna elements and beam scanning bandwidth, the limitation of the beam scanning bandwidth of the log-periodic dipole uniform linear array without grating lobes and without overlap between antenna elements can be obtained. This can achieve the effect of maximizing the bandwidth of the linear array under the premise that the linear array does not have grating lobes and the antenna elements do not overlap.

[0019] Other aspects of the invention will become apparent from the following detailed description with reference to the accompanying drawings. However, it should be understood that the drawings are for illustrative purposes only and not as a limitation of the scope of the invention. It should also be understood that, unless otherwise indicated, the drawings are not necessarily drawn to scale; they are merely intended to conceptually illustrate the structures and processes described herein. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0021] Figure 1 A flowchart of a log-periodic antenna design method considering sidelobe levels is provided for an embodiment of the present invention;

[0022] Figure 2 A schematic diagram of a log-periodic dipole antenna provided in an embodiment of the present invention;

[0023] Figure 3 Normalized radiation patterns of a 16-element uniform linear array under different spacings and scanning angles provided in an embodiment of the present invention;

[0024] Figure 4 This is a schematic diagram of a uniform linear array of log-periodic dipole antennas provided in an embodiment of the present invention;

[0025] Figure 5The horizontal normalized radiation pattern of the log-periodic dipole antenna under different beamwidth factors is provided in the embodiments of the present invention.

[0026] Figure 6 The 16-element log-periodic dipole linear array provided in the embodiments of the present invention ( Normalized radiation pattern when the beam is scanned to 30°;

[0027] Figure 7 The 16-element log-periodic dipole linear array provided in the embodiments of the present invention ( Normalized radiation pattern when the beam is scanned to 30°;

[0028] Figure 8 The 16-element log-periodic dipole linear array provided in the embodiments of the present invention ( Normalized radiation pattern when the beam is scanned to 30°;

[0029] Figure 9 The 16-element log-periodic dipole linear array provided in the embodiments of the present invention ( Normalized radiation pattern when the beam is scanned to 30°;

[0030] Figure 10 The 16-element log-periodic dipole linear array provided in the embodiments of the present invention ( Normalized radiation pattern when the beam is scanned to 30°;

[0031] Figure 11 This is a schematic diagram showing the angles of the grating lobes at different spacings provided in an embodiment of the present invention;

[0032] Figure 12 This is a simulation model diagram of a log-periodic dipole antenna provided in an embodiment of the present invention;

[0033] Figure 13 This is a gain curve diagram of a log-periodic dipole antenna provided in an embodiment of the present invention;

[0034] Figure 14 A VSWR curve of a log-periodic dipole antenna provided in an embodiment of the present invention;

[0035] Figure 15 A beamwidth curve of a log-periodic dipole antenna provided in an embodiment of the present invention;

[0036] Figure 16 Simulation comparison radiation patterns of a log-periodic dipole antenna in the horizontal plane provided in an embodiment of the present invention;

[0037] Figure 17 A simulation model diagram of a 16-element horizontal log-periodic dipole linear array provided in an embodiment of the present invention;

[0038] Figure 18 A horizontal radiation pattern of a 16-element horizontal log-periodic dipole linear array (30MHz) provided for an embodiment of the present invention;

[0039] Figure 19 The horizontal plane pattern of a 16-element horizontal log-periodic dipole linear array (20MHz) provided for an embodiment of the present invention. Detailed Implementation

[0040] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described with reference to the accompanying drawings and embodiments.

[0041] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments, and should all fall within the protection scope of the present invention.

[0042] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this invention are applicable in distinguishing similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or applicable to such processes, methods, products, or apparatus.

[0043] It should also be noted that the division of multiple embodiments in this invention is only for the convenience of description and should not constitute a special limitation. Features in various embodiments can be combined and referenced in each other without contradiction.

[0044] like Figure 1As shown, this invention proposes a design method for a log-periodic antenna linear array considering sidelobe levels. For example, it includes: Step S1, obtaining a normalized direction function showing the influence of the main lobe direction of a uniform linear array composed of several log-periodic dipole antenna elements on the beamwidth of each antenna element; Step S2, obtaining the correspondence between the maximum sidelobe level and the beamwidth based on the normalized direction function, and obtaining the beamwidth factor corresponding to the target sidelobe level based on the correspondence; Step S3, determining the scaling factor and spacing factor of the corresponding antenna elements based on the beamwidth factor; Step S4, determining the antenna array gain based on the scaling factor and the spacing factor, and determining the number of antenna elements in the uniform linear array based on the antenna array gain; and Step S5, determining the minimum operating frequency of the uniform linear array based on the normalized direction function, and calculating the oscillator parameters of the corresponding antenna elements based on the maximum operating frequency, the scaling factor, and the spacing factor, thus completing the linear array design.

[0045] Specifically, a Log-Periodic Dipole Antenna (LPDA) consists of several parallel symmetrical dipoles, all with their structures varying proportionally. Each dipole is connected to a pair of transmission lines called the feed lines, and is fed through these feed lines. To achieve coaxial cable feeding, a balun is typically used connected at the center of the shortest dipole. To achieve directivity of radiation (from the longest dipole to the shortest dipole), the arms of adjacent dipoles are cross-fed. By short-circuiting the feed line terminals or adding a matching load, terminal reflections can be reduced, thereby improving its low-frequency VSWR characteristics.

[0046] The schematic diagram of the log-periodic dipole antenna is shown below. Figure 2 As shown, it consists of N parallel oscillators. The length of the i-th oscillator is... The radius of the oscillator section is... Its distance from the (virtual) vertex O is , This represents the distance between the i-th element and the (i+1)-th element. Typically, the structure of a log-periodic dipole antenna satisfies the following relationship:

[0047] (1)

[0048] (2)

[0049] (3)

[0050] , , These are respectively called the scaling factor, the interval factor, and the imaginary vertex angle. They satisfy the following relationship:

[0051] (4)

[0052] The number of elements in a log-periodic dipole antenna is related to the required operating bandwidth and gain factor. Higher gain requires more elements, and a larger scaling factor. It is typically determined by the following formula:

[0053] (5)

[0054] , (6)

[0055] These represent the antenna's highest and lowest operating frequencies, respectively.

[0056] The length of the dipole element in a log-periodic dipole antenna is also related to the operating frequency range of the designed antenna. In engineering, a cutoff factor is often used. and To determine the lengths of the longest and shortest oscillators. , . and These are called the low-frequency cutoff coefficient and the high-frequency cutoff coefficient, and their magnitudes depend on the scaling factor and the interval factor. The specific calculation formulas are as follows:

[0057] (7)

[0058] (8)

[0059] In step S1, a uniform linear array consisting of M point source antennas with a spacing of d is formed, and the phase difference of the feed current between the antenna elements is... According to antenna array theory, the direction function of its main lobe direction varying with the feed phase can be expressed as:

[0060] (9)

[0061] in, , For total phase, is the wave constant.

[0062] When the array elements are fed in phase ( When the feed is changed, due to the structural symmetry, the uniform linear array will generate maximum radiation (main lobe) at 0° and 180°. At this time, the main lobe points to This is the working principle of a phased array antenna: changing the feed phase of the antenna elements to change the direction of maximum radiation.

[0063] The normalized direction pattern of a uniform linear matrix can be drawn according to formula (9). Figure 2 Normalized radiation patterns of a 16-element uniform linear array under different scanning angles and spacings are presented. It is evident that when the element spacing is too large, a region the same size as the main lobe will appear in other directions; this is called a grating lobe. The appearance of a grating lobe means that the antenna's radiated energy is not concentrated, thus leading to a decrease in directivity. Therefore, the appearance of grating lobes is generally avoided when designing antenna arrays. According to antenna array theory, the condition for an antenna array radiation pattern to not exhibit grating lobes is:

[0064] (10)

[0065] Figure 3 The normalized radiation patterns of a 16-element uniform linear array under different spacings and scanning angles are shown below. The maximum spacing values ​​corresponding to different scanning angles can be calculated according to formula (10), as shown in Table 1 below:

[0066] Table 1 shows the maximum spacing values ​​corresponding to different scanning angles.

[0067]

[0068] Table 1 shows that when the scanning angle... , .from Figure 3 The normalized directional patterns of the given 16-element uniform linear array at different maximum scan angles of 30° and different spacings clearly show that when At that time, grating lobes appeared. From Figure 3 It can be found that when At this point, a grating lobe will appear in the 150° direction, mainly due to the symmetry of the linear array and the non-directionality of the point source antenna.

[0069] Based on the working principle of log-periodic antennas, they are classified as medium-gain antennas. To improve the directivity of the system, an antenna array composed of log-periodic antennas can be used, and the beam can be scanned by changing the feed phase of each antenna element. A uniform linear array is the simplest type of array to feed and has wide applications. For horizontally mounted log-periodic dipole antennas as antenna elements, as shown... Figure 4 The diagram shows a uniform linear array. Horizontal beam scanning capability is achieved by changing the feed phase of the antenna elements.

[0070] According to the pattern product theorem, by The normalized direction function of a uniform linear array composed of log-periodic dipole antennas can be expressed as:

[0071] (11)

[0072] In the formula The direction function of a log-periodic dipole antenna is called the self-factor, which depends only on the antenna element. Formula (1) is called the array factor, which depends only on the array configuration and is independent of the antenna elements. Since it is necessary to achieve beam scanning of the log-periodic dipole antenna array on the horizontal plane (called the beamforming surface), the value in formula (11) is... It can be selected as a horizontal plane direction function.

[0073] Specifically, for example, using Let represent the horizontal direction function of the log-periodic dipole antenna. Defined as the beamwidth factor, its magnitude is related to the horizontal beamwidth of the log-periodic dipole antenna, and the following relationship exists:

[0074] (12)

[0075] in, This represents the 3dB beamwidth of a log-periodic dipole antenna in the horizontal plane.

[0076] Figure 5 The normalized horizontal radiation pattern of the log-periodic dipole antenna under different m values ​​is presented. Table 2 below shows the m values ​​corresponding to different horizontal beamwidths. It can be found that the larger the beamwidth factor, the narrower the horizontal beamwidth.

[0077] Table 2. m values ​​corresponding to different horizontal beamwidths

[0078]

[0079] According to the pattern product theorem, the normalized directional function of the horizontal plane of a log-periodic dipole antenna linear array can be expressed as:

[0080] (13)

[0081] in, .

[0082] like Figures 6-10 Normalized radiation patterns of a 16-element log-periodic dipole linear array with a beam scanning angle of 30° at different spacings are presented.

[0083] Figure 6 Normalized radiation patterns of a linear array consisting of 16 log-periodic antennas are given at different beamwidths when the beam is scanned to 30°. Due to the spacing at this time To meet the requirement of no grating lobes, no grating lobes appeared in the radiation pattern of the antenna array when different values ​​of m were taken for the log-periodic dipole antenna. Furthermore, the directivity of the log-periodic dipole antenna also suppressed grating lobes caused by the structural symmetry of the linear array itself. The figure also shows that the larger the value of m, the narrower the beamwidth of the log-periodic dipole antenna and the lower the sidelobe level of the antenna array. Controlling the beamwidth of the log-periodic dipole antenna elements can effectively reduce the sidelobe level.

[0084] Figure 7 The element spacing is given The radiation pattern when the 16-element linear array is scanned to 30°. From the image, it can be observed that, due to... This exceeds the limitation of no grating lobes in Table 1, and at this point, the array factor exhibits three grating lobes. When the direction function of the log-periodic dipole antenna is multiplied by the direction function of the array factor, it can be observed that the directivity of the log-periodic dipole antenna effectively suppresses the grating lobes of the linear array. Furthermore, the narrower the beamwidth of the log-periodic dipole antenna, the better the grating lobe suppression effect and the lower the sidelobe level. When m=16, not only are there no grating lobes, but the sidelobe level also drops to -12.5dB.

[0085] Figure 8 , Figure 9 , Figure 10 They were given respectively , , The normalized radiation pattern of a 16-element log-periodic dipole antenna linear array beam scanned to 30° is shown in the figure. It can be observed that the sidelobe level of the antenna array radiation pattern increases with increasing spacing. Furthermore, it is found that when the spacing becomes large enough (e.g., ...), the sidelobe level of the antenna array radiation pattern increases. At this point, regardless of the value of the beamwidth factor m of the log-periodic dipole antenna element, the maximum beam pointing direction is not in the 30° direction. Therefore, for a uniform linear array, the angle corresponding to the generation of grating lobes due to excessive spacing is:

[0086] (14)

[0087] Figure 11 The angles corresponding to different grating lobe spacings are given. When the array normal of a linear array is 0°, it is usually used... To describe its beam scanning range. Positive and negative signs simply represent the scanning direction. Due to structural symmetry, usually only one direction needs to be analyzed. In this paper, the scanning angle is described as positive. Then it is negative; conversely, when the scanning angle is negative, then... Then it is positive. From Figure 11It can be observed that as the spacing gradually increases, the uniform linear array will develop grating lobes, and the positions of the grating lobes gradually move towards the 0° direction. At that time, due to the self-factor direction function ( symmetry, Since the values ​​of the matrix factor direction functions are all the same (both are 1), according to the pattern product theorem, we can obtain... This inevitably leads to the main lobe shifting.

[0088] Therefore, to avoid main lobe shift and the appearance of grating lobes, it is required that... In other words, the following conditions should be met:

[0089] (16)

[0090] According to formula (16), the result can be calculated when The spacing constraint condition for a uniform linear array composed of log-periodic dipole antennas without the appearance of grating lobes is as follows: .from Figures 6-10 This condition can also be verified by the normalized directional patterns of log-periodic dipole linear arrays with different spacings.

[0091] Furthermore, log-periodic dipole antennas, composed of several elements, can achieve a very wide operating bandwidth by selecting appropriate scaling and spacing factors. Assume the operating frequency range of the log-periodic dipole antenna is... , These represent the minimum and maximum operating frequencies, respectively. Correspondingly... These represent the wavelengths corresponding to the lowest and highest operating frequencies, respectively.

[0092] Furthermore, when a log-periodic dipole antenna with a wide operating frequency range is horizontally mounted, according to the working principle of log-periodic antennas, the length of the longest element may exceed [a certain value]. This would lead to structural overlap between adjacent array elements. To avoid structural overlap when assembling log-periodic dipole antennas, the spacing between antenna elements must be... Considering the above conditions of no grating lobes and no structural overlap, the time spacing of a uniform linear array of log-periodic dipole antennas should satisfy the following relationship:

[0093] (17)

[0094] Furthermore, the limitation on the scanning bandwidth of a log-periodic dipole uniform linear array beam without grating lobes and structural overlap can be obtained as follows:

[0095] (18)

[0096] From the above formula (18), it can be seen that when the maximum beam scanning angle With a fixed scaling factor, the larger the scaling factor, the greater the bandwidth of the antenna element that can be implemented.

[0097] In step S2, for example, the maximum sidelobe level can be expressed as:

[0098] (19)

[0099] From this formula, it can be seen that when , A value greater than zero means that the main beam has shifted at this point. When , Less than zero, at which point the main lobe points to Furthermore, the sidelobe level can be arbitrarily set to select... And the element spacing, thereby enabling the design of a linear array of low-sidelobe log-periodic dipole antennas.

[0100] Substituting the normalized direction function into the above equation and rearranging, we get:

[0101] (20)

[0102] Therefore, by substituting the preset target sidelobe level into formula (20), the corresponding beamwidth factor can be calculated.

[0103] In step S3, the scaling factor can be obtained by referring to Table 3 based on the beamwidth factor. and interval factor Preferably, when multiple sets of scaling factors and interval factors meet the requirements, the largest scaling factor is selected.

[0104] Table 3. E-plane radiation pattern and half-power angle of log-periodic dipole array antenna

[0105]

[0106] In step S4, the gain value that the antenna array can achieve is first determined based on the scaling factor and the spacing factor. Then, the antenna array gain was adjusted. The number of antenna array elements M is determined by formula (21) according to the requirements:

[0107] (twenty one)

[0108] In the formula The image gain of an antenna mounted on the ground is typically about 5 to 6 dB.

[0109] In step S5, the highest operating frequency of the log-periodic dipole antenna linear array that meets the requirements can be obtained according to formula (18), and the lowest operating frequency can be calculated according to the beamwidth factor. Furthermore, the structural parameters such as the number of oscillators N, the length of each oscillator, and the spacing between each oscillator can be calculated according to formulas (1)-(8).

[0110] The following examples illustrate the specific implementation methods and effects:

[0111] Assuming the antenna array to be designed has a gain of 17 dBi and a maximum scanning angle of... Maximum sidelobe level Maximum operating frequency The operating wavelength is Let's begin the design:

[0112] (1) , Bring into The maximum spacing without grating lobes can be calculated to be 10m. 10m is the upper limit of the element spacing; for convenience, it is chosen here. ;

[0113] (2) , as well as Substituting into formula (19), the beamwidth factor can be calculated. ;

[0114] (3) Substituting into formula (12), the horizontal beamwidth of the log-periodic dipole antenna is calculated to be 60.3°. The scaling factor can be obtained from Table 3. and interval factor ;

[0115] (4) Based on the scaling factor and interval factor From the table, the gain of a log-periodic dipole antenna in free space is approximately... ;

[0116] (5) According to formula (20), the number of antenna elements can be calculated to be 8;

[0117] (8) According to formula (17), we can obtain ,Will Substituting, we can obtain To ensure that the structures do not overlap, take Therefore, the minimum operating frequency can be calculated to be approximately ;

[0118] (9) Substituting into formulas (5) and (6), the length of the oscillator and the distance between them can be calculated, as shown in Table 4.

[0119] Table 4. Log-periodic dipole antenna structure

[0120]

[0121] Alternatively, for example, a simulation model of a log-periodic dipole antenna can be established using FEKO software based on the structural parameters in Table 4, such as... Figure 12 As shown. The antenna material is set to an ideal conductor. The simulation frequency is 20MHz~30MHz, with a frequency interval of 0.5MHz.

[0122] Figures 13-15 The gain, VSWR, and horizontal beamwidth of a log-periodic dipole antenna in free space are presented as a function of frequency. Figure 13 As can be seen, the log-periodic dipole antenna designed according to the previous design process has a gain of around 9 dBi across the entire frequency band, which is in very good agreement with the theoretical estimate. From Figure 14 The standing wave curves show that the standing wave ratio is less than 1.5 across the entire frequency band. From... Figure 15 The beamwidth variation with frequency reveals that the horizontal beamwidth is uniformly around 60° across the entire frequency band.

[0123] Figure 16 A comparison is given between the horizontal radiation pattern simulated using beamwidth and the horizontal radiation pattern calculated by FEKO simulation. It can be seen from the figure that the difference between the two is small.

[0124] Based on the gain curves of the previously designed unit antennas, the gain of the designed log-periodic dipole antenna is approximately 9 dBi, which is consistent with the theoretical estimate. A system is established using 16 of the previously designed log-periodic dipole antennas spaced 8 meters apart. Figure 17 A linear array.

[0125] Figure 18 and Figure 19 The horizontal plane radiation patterns of beam scanning to 0°, 15°, and 30° are given for the highest design frequency of 30MHz and the lowest operating frequency of 20MHz in the design band, respectively.

[0126] from Figure 18 It can be observed that the linear array has gains of 20.4 dBi, 20.1 dBi, and 18.6 dBi at an operating frequency of 30 MHz, with relative sidelobe levels of -13.7 dB, -13.2 dB, and -5 dB, respectively, and the sidelobe angles are all 48°. Figure 19It can be found that the linear array has gains of 18.9dBi, 18.7dBi, and 18.1dBi at an operating frequency of 20MHz, and relative sidelobe levels of -13.6dB, -12.7dB, and -12.1dB, respectively.

[0127] The simulation examples above verify the design method of the log-periodic dipole antenna linear array proposed in this patent, which can effectively control the sidelobe level.

[0128] In summary, the log-periodic antenna linear array design method considering sidelobe levels proposed in this embodiment of the invention analyzes the relationship between the sidelobe levels of antenna elements and the beam scanning bandwidth. This allows the required sidelobe levels to be achieved by controlling the beam scanning bandwidth. The beam scanning bandwidth can be achieved through the structural parameter design of the log-periodic dipole antenna linear array, avoiding the need for additional control devices and computational complexity.

[0129] In addition, the second embodiment of the present invention also proposes a design device for a log-periodic antenna linear array considering sidelobe levels, which includes, for example, a normalized direction function acquisition module, a beamwidth factor acquisition module, a scaling / spacing factor determination module, an antenna element number determination module, and an element parameter calculation module.

[0130] The normalized direction function acquisition module is used to acquire the normalized direction function of the main lobe direction of a uniform linear array composed of several log-periodic dipole antenna elements, which is affected by the beam scanning width of the antenna elements themselves. The beamwidth factor acquisition module is used to obtain the correspondence between the maximum sidelobe level and the beam scanning width based on the normalized direction function, and to obtain the beamwidth factor corresponding to the target sidelobe level based on the correspondence. The scaling / spacing factor determination module is used to determine the scaling factor and spacing factor of the corresponding antenna elements based on the beamwidth factor. The antenna element quantity determination module is used to determine the antenna array gain based on the scaling factor and the spacing factor, and to determine the number of antenna elements in the uniform linear array based on the antenna array gain. The vibrator parameter calculation module is used to determine the minimum operating frequency of the uniform linear array based on the normalized direction function, and to calculate the vibrator parameters of the corresponding antenna elements based on the maximum operating frequency, the scaling factor, and the spacing factor, thus completing the linear array design.

[0131] The design method for a log-periodic antenna linear array considering sidelobe levels, implemented by the log-periodic antenna linear array design device considering sidelobe levels disclosed in the second embodiment of the present invention, is as described in the first embodiment above, and therefore will not be described in detail here. Optionally, each module and the other operations or functions described above in the second embodiment are for implementing the method described in the first embodiment, and the beneficial effects of this embodiment are the same as those of the first embodiment above. For the sake of brevity, they will not be repeated here.

[0132] A third embodiment of the present invention also proposes an electronic device, including, for example, a memory and one or more processors connected to the memory. The memory stores a computer program, and the processor executes the computer program to implement the log-periodic antenna linear array design considering sidelobe levels as described in the first embodiment. The specific method for designing a log-periodic antenna linear array considering sidelobe levels can be referred to the method described in the first embodiment, and will not be repeated here for simplicity. Furthermore, the beneficial effects of the electronic device provided in this embodiment are the same as those of the log-periodic antenna linear array design method considering sidelobe levels provided in the first embodiment.

[0133] The third embodiment of the present invention also proposes a computer-readable storage medium, which is a non-volatile memory storing computer-readable instructions. When the computer-readable instructions are executed by one or more processors, for example, the one or more processors execute the log-periodic antenna linear array design method considering sidelobe levels described in the first embodiment. The specific method can be referred to the method described in the first embodiment, and for simplicity, it will not be repeated here. Furthermore, the beneficial effects of the computer-readable storage medium provided in this embodiment are the same as those of the log-periodic antenna linear array design method considering sidelobe levels provided in the first embodiment.

[0134] Furthermore, it is understood that the foregoing embodiments are merely illustrative examples of the present invention. Provided that the technical features do not conflict, the structure is not contradictory, and the purpose of the invention is not violated, the technical solutions of the various embodiments can be arbitrarily combined and used.

[0135] In the several embodiments provided by this invention, it should be understood that the disclosed systems, devices, and / or methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative; for instance, the division of units / modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or modules may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0136] The units / modules described as separate components may or may not be physically separate. The components shown as units / modules may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units / modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0137] Furthermore, in the various embodiments of the present invention, the functional units / modules can be integrated into one processing unit / module, or each unit / module can exist physically separately, or two or more units / modules can be integrated into one unit / module. The integrated unit / module described above can be implemented in hardware or in the form of hardware plus software functional units / modules.

[0138] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for designing a log-periodic antenna linear array considering sidelobe levels, characterized in that, include: Obtain the normalized direction function of the main lobe direction of a uniform linear array composed of several log-periodic dipole antenna elements, which is affected by the beam scanning width of the antenna elements themselves. The correspondence between the maximum sidelobe level and the beam scanning width is obtained based on the normalized direction function, and the beam width factor corresponding to the target sidelobe level is obtained based on the correspondence. The scaling factor and spacing factor of the corresponding antenna element are determined based on the beamwidth factor. The antenna array gain is determined based on the scaling factor and the spacing factor, and the number of antenna elements in the uniform linear array is determined based on the antenna array gain. as well as The minimum operating frequency of the uniform linear array is determined based on the normalized direction function, and the oscillator parameters of the corresponding antenna elements are calculated based on the maximum operating frequency, the scaling factor, and the spacing factor, thus completing the linear array design. The normalized direction function is: ;in, For the number of antenna elements, , Defined as beamwidth factor; where, d is the wave constant, and d is the spacing between antenna elements. The angle between the main lobe and the normal, Main lobe direction; The step of obtaining the correspondence between the maximum sidelobe level and the beamwidth factor based on the normalized direction function includes: The sidelobe level is expressed as: ;in, Indicates the direction of the main lobe. Indicates the angle of the grid lobe.

2. The method for designing a log-periodic antenna linear array considering sidelobe levels according to claim 1, characterized in that, The step of obtaining the beamwidth factor corresponding to the target sidelobe level based on the correspondence includes: The calculated beamwidth factor is: .

3. The design method for a log-periodic antenna linear array considering sidelobe levels according to claim 1, characterized in that, Determining the number of antenna elements in the uniform linear array based on the antenna array gain includes: The gain of the antenna array is expressed as: The number of antenna elements is calculated in this way. ;in, For antenna element gain in free space, This represents the image gain of the antenna element.

4. The method for designing a log-periodic antenna linear array considering sidelobe levels according to claim 2, characterized in that, Determining the minimum operating frequency of the uniform linear matrix based on the normalized direction function includes: The range of antenna element spacing in which the uniform linear array does not exhibit grating lobes and the antenna elements do not overlap is obtained based on the normalized direction function. The corresponding beam scanning bandwidth is determined based on the range of antenna element spacing, and the minimum operating frequency is determined based on the beam scanning bandwidth and the highest operating frequency.

5. The method for designing a log-periodic antenna linear array considering sidelobe levels according to claim 4, characterized in that, The calculated parameters of the antenna element include: The number of oscillators is calculated based on the highest and lowest operating frequencies. The lengths of the longest and shortest elements are calculated based on the scaling factor and the spacing factor, and the spacing between adjacent elements is calculated based on antenna theory.

6. A design device for a log-periodic antenna linear array considering sidelobe levels, characterized in that, include: The normalized direction function acquisition module is used to acquire the normalized direction function of the main lobe direction of a uniform linear array composed of several log-periodic dipole antenna elements, which is affected by the beam scanning width of the antenna element itself. The beamwidth factor obtaining module is used to obtain the correspondence between the maximum sidelobe level and the beam scanning width according to the normalized direction function, and to obtain the beamwidth factor corresponding to the target sidelobe level according to the correspondence. A scaling / spacing factor determination module is used to determine the scaling factor and spacing factor of the corresponding antenna element based on the beamwidth factor. The antenna element number determination module is used to determine the antenna array gain based on the scaling factor and the spacing factor, so as to determine the number of antenna elements in the uniform linear array based on the antenna array gain. as well as The oscillator parameter calculation module is used to determine the lowest operating frequency of the uniform linear array based on the normalized direction function, and to calculate the oscillator parameters of the corresponding antenna element based on the highest operating frequency, the scaling factor and the spacing factor, thereby completing the linear array design. The normalized direction function is: ;in, For the number of antenna elements, , Defined as beamwidth factor; where, d is the wave constant, and d is the spacing between antenna elements. The angle between the main lobe and the normal, Main lobe direction; The step of obtaining the correspondence between the maximum sidelobe level and the beamwidth factor based on the normalized direction function includes: The sidelobe level is expressed as: ;in, Indicates the direction of the main lobe. Indicates the angle of the grid lobe.

7. An electronic device, characterized in that, include: A memory and one or more processors connected to the memory, the memory storing a computer program, the processors executing the computer program to implement the log-periodic antenna design method considering sidelobe levels as described in any one of claims 1-5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions for performing the log-periodic antenna design method considering sidelobe levels as described in any one of claims 1-5.

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