A frequency scanning slot array antenna and a detection device

Abstract

The application relates to the technical field of antennas, in particular to a frequency scanning slot array antenna and a detection device. The frequency scanning slot array antenna comprises a feeding structure, a 2*30 slot array antenna and a terminal matching structure which are sequentially connected. The 2*30 slot array antenna comprises 30 unit slots arranged at equal intervals in a horizontal plane and 2 unit slots arranged in a pitch plane. The 2 unit slots are arranged in a preset mode. The 30 unit slots arranged in the horizontal plane are designed in a low side lobe mode. In this way, the number of slot units is increased in the non-extension direction of the waveguide to form a narrow beam, the beam width can be controlled by adjusting the number of slots, the antenna structure is simple in design, convenient in processing and small in loss.

Description

Technical Field

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

[0002] Existing frequency-scanning slot array antennas have only a single slot in the non-extension direction (i.e., the elevation direction) of the waveguide. The half-power lobe width of this single slot in the non-extension direction is 40º~70º, resulting in a relatively wide beamwidth; a single slot cannot form a narrow beam. However, if a narrow beam is required in the non-extension direction using existing frequency-scanning slot array antennas, multiple slot array antennas typically need to be connected in parallel using a power divider. This leads to an excessively large antenna area, increasing antenna complexity, and the power divider inevitably introduces losses, reducing antenna gain. Therefore, existing frequency-scanning slot array antennas suffer from structural complexity. Summary of the Invention

[0003] This invention provides a frequency scanning slot array antenna and a detection device to solve the problem of complex structure in existing frequency scanning slot array antennas.

[0004] To achieve the above objectives, the present invention employs the following technical solution:

[0005] In a first aspect, the present invention provides a frequency scanning slot array antenna, comprising: a feeding structure, a 2×30 slot antenna array, and an end matching structure connected in sequence. The 2×30 slot antenna array includes 30 slot elements arranged at equal intervals in the horizontal plane and 2 slot elements arranged in the elevation plane. The 2 slot elements are placed in a preset manner, and the 30 slot elements arranged in the horizontal plane are designed as a low sidelobe design.

[0006] Optionally, the preset method includes the following relationships:

[0007] The two unit gaps are placed alternately on the left and right sides of the waveguide centerline at intervals of half the waveguide wavelength.

[0008] Optionally, the preset method includes the following relationships:

[0009] The two unit slots are placed on the same side of the waveguide wide side centerline at an interval of one waveguide wavelength.

[0010] Optionally, the feeding structure includes a substrate integrated waveguide and a coaxial port, and the design of the substrate integrated waveguide to the coaxial port is a broadband transition design.

[0011] Optionally, the coaxial port is a 50-ohm connector.

[0012] Optionally, the first end of the power supply structure is provided with a first tuning inductor post, and the second end of the power supply structure is provided with a second tuning inductor post.

[0013] Optionally, the end-matching structure includes a matching antenna, which is a half-wave circular dipole antenna.

[0014] Optionally, the power supply length between adjacent slot units of the 30 slot units arranged in the horizontal plane is greater than a preset length threshold.

[0015] Optionally, the difference between the spacing between two adjacent gaps in the 30 gaps arranged in the horizontal plane and half the waveguide wavelength is less than a preset difference.

[0016] Secondly, embodiments of this application provide a detection device, including a frequency scanning slot array antenna as described in the first aspect.

[0017] Beneficial effects:

[0018] The frequency scanning slot array antenna provided by this invention includes a feed structure, a 2×30 slot antenna array, and an end matching structure connected in sequence. The 2×30 slot antenna array comprises 30 slot elements arranged at equal intervals in the horizontal plane and 2 slot elements arranged in the elevation plane. The 2 slot elements are placed in a predetermined manner, and the 30 slot elements arranged in the horizontal plane are designed with low sidelobes. In this way, a narrow beam is formed in the non-extension direction of the waveguide by increasing the number of slot elements. The beamwidth can be controlled by adjusting the number of slots. The antenna structure is simple to design, easy to manufacture, and has low loss. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a frequency scanning slot array antenna according to a preferred embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of a substrate-integrated waveguide structure according to a preferred embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of adjacent gap unit parameters provided in a preferred embodiment of the present invention;

[0022] Figure 4 A schematic diagram of the structure of an existing 1×30 frequency scanning slot antenna;

[0023] Figure 5 The azimuth plane radiation pattern of a 1×30 frequency scanning slot antenna at various frequency points;

[0024] Figure 6 The elevation plane radiation pattern of a 1×30 frequency scanning slot antenna at various frequencies.

[0025] Figure 7 The azimuth plane frequency pattern of the 2×30 frequency scanning slot antenna provided in the preferred embodiment of the present invention;

[0026] Figure 8 The elevation plane frequency pattern of the 2×30 frequency scanning slot antenna provided in the preferred embodiment of the present invention is shown. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below. 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.

[0028] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "connected" or "linked" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up," "down," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship also changes accordingly.

[0029] Existing frequency-scanning slot array antennas have a single slot in the elevation plane, making it difficult to form a narrow beam in the elevation plane and a large-angle scan in the horizontal plane. However, when a power divider is used to array the antennas in the elevation plane, even if the elevation beam is narrow, the size is large, the loss is high, and the structure and operation are complex. In view of this, this application provides a frequency-scanning slot array antenna.

[0030] Please see Figure 1 This application provides a frequency scanning slot array antenna, wherein ZOY is the elevation plane. The frequency scanning slot array antenna includes: a feed structure, a 2×30 slot antenna array, and an end matching structure connected in sequence. The 2×30 slot antenna array includes 30 slot elements arranged at equal intervals in the horizontal plane and 2 slot elements arranged in the elevation plane. The 2 slot elements are placed in a preset manner. The 30 slot elements arranged in the horizontal plane are designed with low sidelobes.

[0031] It should be noted that the frequency scanning slot array antenna mentioned above is a miniaturized wide-angle frequency scanning slot array antenna. The microwave operating mode is the TE10 mode, and it is a traveling wave array antenna. The operating frequency is in the Ku band, specifically 15.7GHz-17.7GHz.

[0032] In this embodiment, the 2×30 slot antenna array includes 30 equally spaced slot elements in the horizontal plane and 2 slot elements in the elevation plane. These two slot elements are alternately placed at intervals of half the waveguide wavelength from the waveguide centerline. The horizontal plane slots employ a low sidelobe design, achieving a half-power beamwidth of approximately 6.5º in the horizontal plane and 33º in the elevation plane. This allows for a reduction in elevation beamwidth without the need for an additional power divider, achieving miniaturization. Simultaneously, the addition of slot elements in the elevation plane enables a wider frequency beam scanning capability, increasing the beam scanning angle from the previous -32º-34º to the current -48º-50º, achieving wide-angle scanning.

[0033] In this way, the frequency scanning slot array antenna described above forms a narrow beam in the non-extending direction of the waveguide by increasing the number of slot elements. The beamwidth can be controlled by adjusting the number of slots. The antenna structure is simple to design, easy to manufacture, and has low loss.

[0034] Optionally, the above-mentioned preset methods include the following relationships:

[0035] The two unit slots are placed alternately on the left and right sides of the waveguide centerline at intervals of half the waveguide wavelength.

[0036] Alternatively, the above-mentioned preset methods include the following relationships:

[0037] Two unit slots are placed on the same side of the wide side centerline of the waveguide at intervals of one waveguide wavelength.

[0038] It should be noted that, in order to improve the overall antenna gain and further reduce the half-power beamwidth in the elevation plane, the conventional approach is to use a power divider. For example, a 1-to-2 power divider can be used to feed the two-antenna array. However, this arrangement inevitably doubles the volume of the elevation plane, and the increased size also leads to increased array losses. In this optional embodiment, an additional element is added in the elevation direction to form a 2×30 slotted array. To ensure that the two antenna arrays are superimposed in phase, the vertical center distance between the two elements in the elevation direction is... They are placed alternately on opposite sides of the centerline of the wide-side waveguide; they can also be tilted towards two slot units at intervals. Placed on the same side as the centerline of the wide side of the waveguide. This represents a waveguide wavelength.

[0039] In one example, to reduce the volume, opposite-side placement can be used.

[0040] Optionally, the feed structure includes a substrate-integrated waveguide and a coaxial port, with the substrate-integrated waveguide to the coaxial port designed as a broadband transition. The coaxial port is a 50-ohm connector. This facilitates connection to external integrated circuits.

[0041] When a substrate integrated waveguide structure is used, the substrate integrated waveguide structure is shown below. Figure 2 As shown, its upper and lower surfaces are metal layers, and the middle is a dielectric substrate. Two rows of metallized vias are equally spaced on both sides of the upper and lower metal layers and the dielectric, thus forming a planar waveguide circuit structure. Essentially, it is a dielectric-filled rectangular waveguide. Its width is 'a', representing the spacing between the upper and lower rows of metal vias; the period of the via array is 'p', the diameter is 'd1', and the dielectric thickness is 'h'.

[0042] When p < 2d1 and d1 < 0.2a, the energy leakage between vias can be ignored. In this case, the substrate integrated waveguide is equivalent to a dielectric rectangular waveguide, and the design method of the rectangular waveguide slot antenna can be used to design the slot antenna of this invention.

[0043] Specifically, the principle of a frequency scanning antenna is as follows:

[0044] By changing the antenna's feed frequency, the wavelength of each feed frequency will change, the normalized distance between adjacent slot elements will change, the phase of the electromagnetic wave arriving at each antenna slot element will also change, and thus the direction of the maximum radiation of the main lobe will change. Figure 3 This is a schematic diagram of adjacent slot parameters. d represents the horizontal spacing between adjacent slot elements, and L represents the feed length between adjacent slot elements, calculated according to the phase formula. It can be seen that when the feed length L is an integer multiple of the wavelength, the phase of each frequency point is related to the working wavelength in the waveguide. The working wavelength of each feed frequency is different, which leads to different phases of each feed frequency. As a result, the main beam direction of each feed frequency is different, thus realizing the frequency scanning function of the antenna.

[0045] Optionally, the first end of the power supply structure is provided with a first tuning inductor post, and the second end of the power supply structure is provided with a second tuning inductor post. In this way, broadband transition design can be completed simultaneously, achieving broadband matching.

[0046] Optionally, the end-matching structure includes a matching antenna, which is a half-wave circular dipole antenna. This allows it to absorb echoes from inside the waveguide while also radiating the absorbed energy, further widening the antenna bandwidth.

[0047] Optionally, the feed length between adjacent slot units is greater than a preset length threshold.

[0048] It is worth noting that since the feed length L is related to the antenna beam scanning angle, in order to make the scanning angle larger, the feed length between adjacent slot elements should be greater than the preset length threshold, so as to increase the electromagnetic wave propagation distance as much as possible. In this embodiment, a serpentine slow wave line structure is used for design.

[0049] Optionally, the difference between the spacing between two adjacent slots in the 30 slots arranged in the horizontal plane and half the waveguide wavelength is less than a preset difference. This ensures that no grating lobes appear in the main beams at each feed frequency.

[0050] In one example, the specific design process of this application is as follows:

[0051] The design employs a traveling-wave array frequency-scanning slot antenna. Electromagnetic signal energy is input from a 50-ohm coaxial port, passes through the slot, and radiates into space. The remaining energy is transmitted to the end, absorbed by the matched load antenna, and then radiated outwards. Based on equivalent waveguide theory, the dominant mode propagated in the equivalent dielectric waveguide is the TE10 mode, and the waveguide wavelength within the waveguide is... The waveguide wavelength is determined by the equivalent waveguide width a1, which is derived from a, d1, and p within the substrate-integrated waveguide. The waveguide wavelength formula is as follows:

[0052]

[0053] Therefore, by changing the equivalent waveguide width a1, the waveguide wavelength... With change, This indicates the operating wavelength in the medium, and further depends on the beam direction of the waveguide radiation. , Where m is a positive integer, Let θ be the waveguide wavelength at the center frequency and θ be the maximum beam pointing direction. Therefore, by changing the equivalent dielectric waveguide width a1, the feed length L, and the spacing between adjacent slots d, the antenna beam pointing can be changed to achieve beam scanning.

[0054] To achieve high gain and low sidelobes in the antenna, with a horizontal half-power beamwidth of approximately 6.5º, this application employs 30 wide-side longitudinal slot elements arranged horizontally, and uses Taylor weighting to design the amplitudes of these 30 slot elements. To prevent grating lobes from appearing in the main beam at each feed frequency, the spacing d should be close to half the waveguide wavelength. Through Taylor weighting, the amplitude values ​​of each slot are calculated, and the normalized equivalent conductance of each slot is further determined. The offset distance of each slot is then calculated; the offset distance is the horizontal distance between the slot center and the centerline of the wide side of the waveguide. A larger offset distance results in a larger amplitude; typically, the offset distances at both ends are smaller, and the offset distance in the middle is larger. Furthermore, the slot length is approximately half the operating wavelength, and the slot width is 1 mm.

[0055] The final structure diagram of a single 1×30 slot element frequency scanning slot antenna array is as follows: Figure 4 As shown, the azimuth pattern data for each frequency point of several key frequencies are as follows: Figure 5 As shown, the radiation pattern data at each frequency point on the elevation plane are as follows: Figure 6 As shown, the horizontal axis represents the azimuth angle, and the vertical axis represents the gain value. Within the 15.7GHz-17.7GHz frequency sweep beam coverage range of -32.2° to 34.8°, the gain is greater than 14.7dB, the maximum gain is 17.7dB, the sidelobe level is greater than 20dB, the azimuth half-power beamwidth is 5.2°±0.3°, and the elevation half-power beamwidth is 42°~66°.

[0056] To improve the overall antenna gain and further reduce the half-power beamwidth in the elevation plane, the conventional approach is to use a power divider.

[0057] For example, a 1-to-2 power divider can be used to feed a two-antenna array. However, this arrangement inevitably doubles the volume of the elevation plane, and the increased size also leads to increased array losses. Therefore, this application directly adds an array element in the elevation direction to form a 2×30 slotted array. To ensure that the two antenna arrays are in phase and superimposed, the vertical center distance between the two elements in the elevation direction is... They are placed alternately on opposite sides of the centerline of the wide-side waveguide; they can also be tilted towards two slot units at intervals. They are placed on the same side of the centerline of the wide side of the waveguide. In order to reduce the size, this application uses opposite sides.

[0058] The final structure diagram of a single 2×30 slot element frequency scanning slot antenna array is shown below. Figure 1 As shown, the azimuth pattern data for each frequency point of several key frequencies are as follows: Figure 7 As shown, the radiation pattern data at each frequency point on the elevation plane are as follows: Figure 8 As shown. In the 15.7GHz-17.7GHz frequency sweep beam coverage range of -48°~50°, the gain is greater than 15.6dB, the maximum gain is 19dB, the sidelobe level is greater than 21dB, the azimuth plane half-power beamwidth is 6.5°±0.5°, and the elevation plane half-power beamwidth is 35°±5°.

[0059] A single antenna can cover a frequency sweep beam range of -48° to 50° in the 15.7GHz-17.7GHz range, which means it can achieve beam scanning in the range of -45° to 45°. Therefore, one transmit and two receive antennas can be used to detect drones in the range of -45° to 45°. At the same time, four transmit and two receive antennas arranged in a circle can be used to detect drones in the range of 360°.

[0060] To reduce the half-power beamwidth in the elevation direction, power dividers are conventionally used for antenna arraying. This arraying inevitably increases the elevation volume, and when the number of arrays is an even number (2, 4, or 8 or more), the elevation volume becomes even larger, increasing structural complexity. The method described above can directly increase the number of arrays in the elevation direction to reduce beamwidth, decrease losses, increase gain, and simplify structural complexity. Furthermore, traditional arraying methods use power dividers, so the number of arrays can only be even, while the number of arrays in this application can be either odd or even, allowing for flexible application based on the elevation beamwidth specification and facilitating design.

[0061] It should be noted that in the other examples, the slot antenna can also be a wide-side oblique slot, a wide-side horizontal slot, etc. The slot antenna in this application can be used for frequency scanning of both traveling-wave array antennas and standing-wave array antennas. The waveguide structure of the arrangement in this application can be used for substrate integrated waveguides, metallic waveguides, and metallic ridge waveguides, but the frequency scanning beam range of metallic waveguides is smaller than that of substrate integrated waveguides and metallic ridge waveguides. The end matching structure in this application can be a matching antenna or a 50-ohm matching port. The feeding structure in this application is a transition from a substrate integrated waveguide to a coaxial port, or it can be a transition from a substrate integrated waveguide to a microstrip. This is merely an example and not a limitation.

[0062] This application also provides a detection device, including the frequency scanning slot array antenna as described above. The detection device includes various embodiments of the frequency scanning slot array antenna described above and achieves the same beneficial effects; therefore, further details are omitted here.

[0063] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A frequency-scanning slot array antenna, characterized in that, include: The feed structure, the 2×30 slot antenna array, and the end matching structure are connected in sequence. The 2×30 slot antenna array includes 30 slot elements arranged at equal intervals in the horizontal plane and 2 slot elements arranged in the elevation plane. The 2 slot elements are placed in a preset manner. The 30 slot elements arranged in the horizontal plane are designed with low sidelobes. The feeding length between adjacent slot units of the 30 slot units arranged in the horizontal plane is greater than a preset length threshold, wherein the feeding structure is designed with a serpentine slow wave line structure. The difference between the spacing between two adjacent gaps in the 30 gaps arranged in the horizontal plane and half the waveguide wavelength is less than a preset difference. The preset method includes the following relationships: The two-unit slots are placed alternately on the left and right sides of the waveguide centerline at an interval of half a waveguide wavelength; or, the two-unit slots are placed on the same side of the waveguide centerline at an interval of one waveguide wavelength.

2. The frequency scanning slot array antenna according to claim 1, characterized in that, The feeding structure includes a substrate integrated waveguide and a coaxial port, and the design of the substrate integrated waveguide to the coaxial port is a broadband transition design.

3. The frequency scanning slot array antenna according to claim 2, characterized in that, The coaxial port is a 50-ohm connector.

4. The frequency scanning slot array antenna according to claim 2, characterized in that, The first end of the power supply structure is provided with a first tuning inductor post, and the second end of the power supply structure is provided with a second tuning inductor post.

5. The frequency scanning slot array antenna according to claim 1, characterized in that, The end-matching structure includes a matching antenna, which is a half-wave circular dipole antenna.

6. A detection device, characterized in that, Includes the frequency scanning slot array antenna as described in any one of claims 1-5.

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