A frequency scanning device

Abstract

The present application relates to a kind of frequency scanning device, belong to frequency scanning technical field.The frequency scanning device includes: feed network and multiple subarrays;Each subarray is connected with feed network;In multiple subarrays, the interval distance between two subarrays is set value, and phase difference is formed between two subarrays.It can be seen that, the present application is with multiple subarrays to carry out the mode of equal interval arrangement, by adjusting subarray interval, excitation phase shift and selecting scanning frequency interval, while realizing frequency scanning function, reduce the width of main beam of pattern, improve resolution, provide a possibility for designing high-resolution frequency scanning radar.And using feed network to carry out amplitude and phase weighting to array, further reduce the sidelobe of array pattern.

Description

Technical Field

[0001] This invention relates to the field of frequency scanning technology, and in particular to a frequency scanning device. Background Technology

[0002] With the rapid development of radar, communication, detection, and imaging technologies, traditional mechanical antennas are no longer sufficient. Therefore, electronically scanned antennas, capable of rapid scanning, have emerged. A frequency scanning device is one type of electronically scanned antenna. By changing the frequency, the optical path difference between elements is altered, causing a change in their phase difference, thus achieving beam scanning. Frequency scanning devices are simple to power, have a moderate size, and are relatively inexpensive.

[0003] If the aperture of the frequency scanning device is too large, it will result in excessively long slow wave lines, which will not only affect efficiency but also limit the scanning range of the radiation pattern. Summary of the Invention

[0004] To address the aforementioned problems in the existing technology, the present invention provides a novel frequency scanning device.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A frequency scanning device includes: a feed network and multiple subarrays;

[0007] Each subarray is connected to the power supply network; among the multiple subarrays, the axial spacing between any two subarrays is a set value, and a phase difference is formed between any two subarrays.

[0008] Preferably, the subarray is a non-resonant waveguide antenna with multiple slots.

[0009] Preferably, the distances of the plurality of slots from the central axis of the non-resonant waveguide antenna follow a Taylor distribution.

[0010] Preferably, the set value is 5λ; where λ is the scanning wavelength.

[0011] Preferably, the number of subarrays is 3.

[0012] Preferably, the power supply network includes a power divider and multiple feeders;

[0013] The number of feed lines is the same as the number of subarrays; each subarray is connected to the power divider via the feed lines.

[0014] Preferably, each feeder has a predetermined length difference with its adjacent feeders.

[0015] Preferably, the preset length is 118mm.

[0016] According to the specific embodiments of the present application, the following technical effects are disclosed:

[0017] The frequency scanning device provided by the present application is arranged in equal intervals by multiple sub-arrays, and by adjusting the interval of the sub-arrays, the excitation phase shift and the scanning frequency interval, the main beam width of the directional diagram is reduced and the resolution is improved while realizing the frequency scanning function, which provides a possibility for designing high-resolution frequency scanning radar. The amplitude and phase weighting is performed on the array by the feed network, and the side lobe of the array directional diagram is further reduced. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0019] Figure 1 The structural schematic diagram of the frequency scanning device provided by the present application is shown in the figure.

[0020] Figure 2 The scanning directional diagram of the sub-array provided by the embodiment of the present application in the range of 14GHz-18GHz is shown in the figure.

[0021] Figure 3 The array factor, the sub-array and the array directional diagram when the axial interval of each sub-array provided by the embodiment of the present application is 5λ are shown in the figure.

[0022] Figure 4 The scanning directional diagram of the array factor when the axial interval of each sub-array provided by the embodiment of the present application is 5λ and the scanning frequency range is 14GHz-18GHz is shown in the figure.

[0023] Figure 5 The array scanning directional diagram when the axial interval of each sub-array provided by the embodiment of the present application is 5λ, the scanning frequency range is 14GHz-18GHz and the length difference of adjacent feed lines is 118mm is shown in the figure.

[0024] Symbol explanation:

[0025] 1-sub-array, 11-matched load, 12-waveguide, 13-slit, 2-feed network, 21-power divider, 22-feed line, 3-excitation. DETAILED DESCRIPTION

[0026] Clearly, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present application.

[0027] The present application aims to provide a frequency scanning device capable of simultaneously being compatible with frequency scanning and narrow lobe, and improving frequency scanning efficiency and scanning range.

[0028] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below in combination with the drawings and specific embodiments.

[0029] As shown in the drawings, Figure 1 The present application provides a frequency scanning device, which comprises a feed network 2 and a plurality of sub-arrays 1.

[0030] Each sub-array 1 is connected with the feed network 2. In order to narrow the main lobe of the directional diagram, the sub-arrays 1 are arranged at equal intervals according to a certain rule, and the axial interval between the sub-arrays 1 is much larger than a wavelength, for example, the interval distance between each two sub-arrays in the plurality of sub-arrays is a set value, and a phase difference is formed between each two sub-arrays to form a staggered arrangement. The set value can be 5λ, and λ is the wavelength of the traveling wave in air. Since the axial size of the sub-array is larger than the axial interval between the sub-arrays, the sub-arrays are placed staggered in the non-axial direction.

[0031] In the present embodiment, the sub-array 1 is a non-resonant waveguide antenna (frequency scanning antenna) provided with a plurality of slits 13. One end of the non-resonant waveguide antenna is fed, and the other end is connected with a matching load 11. In actual application, the number of the slits 13 can be 22. The waveguide 12 used by the non-resonant waveguide antenna is a WR-62 standard waveguide.

[0032] In addition, since the frequency scanning device generally works in the traveling wave state, it has the disadvantage of wide bandwidth. In order to effectively control the sidelobe level, and thus make the entire frequency scanning device have the characteristics of low sidelobe, in the present embodiment, the distance of the plurality of slits 13 from the central axis of the non-resonant waveguide antenna is subject to Taylor distribution. When the number of the slits 13 is 22, the distance from the feeding end to the midpoint of the first slit 13 is λ g / 2, the distance from the matching end (the end connected with the matching load 11) to the midpoint of the last slit 13 is λ g / 4, and the interval distance d of the adjacent two slits 13 is not equal to λ g / 2, and λ g is the waveguide wavelength.

[0033] Further, in this embodiment, the feed network 2 comprises a power divider 21 and a plurality of feed lines 22.

[0034] The number of the feed lines 22 is the same as the number of the sub-arrays 1. Each sub-array 1 is connected to the power divider 21 through a feed line 22. There is a preset length difference between each feed line and its adjacent feed line. For example, the preset length is 118 mm. The feed network 2 ensures the phase difference between the sub-arrays 1 by designing the length of the feed line 22 between the feed source and the sub-array 1, so that the main lobe of the array at each frequency point is not split, and the sidelobe is suppressed. The feed network 2 distributes power to different sub-arrays, and uses amplitude weighting to further reduce the overall sidelobe.

[0035] The power divider 21 is used to distribute the size of the excitation 3, so as to further suppress the sidelobe of the array pattern by optimizing the phase and amplitude of the excitation received by each sub-array 1. When the number of the sub-arrays 1 used is 3, the amplitude ratio of the excitation 3 after passing through the power divider 21 and the feed line 22 is 1:2:1, so as to achieve the purpose of using amplitude weighting to control the position of the zero point or adjusting the position of the zero point of the sub-array 1 pattern through the spacing of the slits 13.

[0036] When the frequency scanning device provided by the embodiment is used for frequency scanning, the main lobe of the pattern points to the frequency point in sequence, and the half-power lobes of the main lobe of the pattern overlap each other. The array factor grating lobe is the same as the position of the zero point of the sub-array pattern, and the sidelobe of the overall pattern of the frequency scanning antenna obtained by multiplying the two is reduced. The array factor zero point corresponds to the part outside the half-power lobe width of the main lobe of the sub-array pattern, so as to reduce the overall sidelobe.

[0037] The feed network 2 uses amplitude weighting to control the amplitude of the array factor sidelobe, adjusts the position of the zero point of the sub-array pattern through the spacing of the slits 13, and adjusts the position of the array factor grating lobe through the spacing between the sub-arrays 1.

[0038] As shown in FIG. 6, the sub-array is scanned in the direction of 14 GHz to 18 GHz. Figure 2 As shown in FIG. 7, when the spacing between the sub-arrays is 5λ, the array factor, the sub-array, the array pattern, and the array factor grating lobe appear at -90°, -53°, -40°, -23°, -12°, 0°, 23°, 40°, 53° and 90°, all of which correspond to the zero point of the sub-array pattern, and the sidelobe is suppressed. The array factor zero point appears on both sides of the main lobe of the sub-array, that is, 7.5° to 9° and 14.5° to 16.5°, which suppresses the sidelobe generated by the split main lobe of the array, that is, narrows the main lobe of the array.

[0039] As shown in FIG. 6, the sub-array is scanned in the direction of 14 GHz to 18 GHz. Figure 3 As shown in FIG. 7, when the spacing between the sub-arrays is 5λ, the array factor, the sub-array, the array pattern, and the array factor grating lobe appear at -90°, -53°, -40°, -23°, -12°, 0°, 23°, 40°, 53° and 90°, all of which correspond to the zero point of the sub-array pattern, and the sidelobe is suppressed. The array factor zero point appears on both sides of the main lobe of the sub-array, that is, 7.5° to 9° and 14.5° to 16.5°, which suppresses the sidelobe generated by the split main lobe of the array, that is, narrows the main lobe of the array.

[0040] As Figure 4 The array scanning directional diagram when the subarray interval is 5λ and the scanning range is 14GHz to 18GHz is shown. It can be seen that at the zero point of the array factor directional diagram, the main lobe of the array scanning directional diagram cannot achieve the mutual overlap of the half-power lobe, and the radiation effect is poor at this scanning angle. In order to solve this problem, phase shift operation needs to be performed on the excitation of each subarray.

[0041] As Figure 5 The array scanning directional diagram when the subarray interval is 5λ, the scanning range is 14GHz to 18GHz, and the length difference of the adjacent subarray feed line is 118mm is shown. It can be seen that within the scanning angle of-1° to 19°, the half-power lobes of the array scanning directional diagram with a frequency difference of 0.1GHz, 0.3GHz or 0.5GHz are mutually overlapped, and effective scanning of the frequency range is achieved. When the antenna is scanning, the average value of the half-power lobe width of the directional diagram is 3°, the average value of the-15dB bandwidth is 6°, and the sidelobe level is-16dB.

[0042] The embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between the embodiments can be referred to each other.

[0043] The principles and implementation manners of the present application are described by using specific examples in the specification. The above description of the embodiments is only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manner and application range can be changed. In summary, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A frequency scanning device, characterized by The application relates to a phased array antenna. The phased array antenna comprises a feeding network and a plurality of sub-arrays; each of the sub-arrays is a non-resonant waveguide antenna with a plurality of slits; Each of the sub-arrays is connected with the feeding network; the axial distance between any two of the sub-arrays is a set value, and a phase difference is formed between any two of the sub-arrays; the set value is 5 lambda; wherein lambda is the scanning wavelength; The feeding network comprises a power divider and a plurality of feeding lines; The number of the feeding lines is the same as the number of the sub-arrays; each of the sub-arrays is connected with the power divider through the feeding lines; and a length difference of a preset length exists between each of the feeding lines and its adjacent feeding line; The power divider is used for distributing the excitation size, so as to further suppress the array pattern side lobe by optimizing the phase and amplitude of the excitation received by each of the sub-arrays; when the number of the sub-arrays is three, the amplitude ratio of the excitation after the power divider and the feeding lines is 1:2:1, so that the purpose of using amplitude weighting to control the zero point position or adjusting the sub-array pattern zero point position through the slit spacing is achieved; the array factor grating lobe is the same as the sub-array pattern zero point position.

2. The frequency scanning apparatus according to claim 1, wherein The distance between the plurality of slits and the central axis of the non-resonant waveguide antenna conforms to a Taylor distribution.

3. The frequency scanning apparatus according to claim 1, wherein The number of the sub-arrays is three.

4. The frequency scanning apparatus according to claim 1, wherein The preset length is 118 mm.

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