An X-band low side lobe waveguide slot antenna
By optimizing the tilt angle and insertion depth of the slot, and adopting Taylor weighted distribution and symmetrical structure design, the problem of high sidelobes in waveguide slot antennas in the prior art has been solved, achieving the effects of low sidelobes, high gain and low loss, and reducing the complexity of processing and debugging.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- WUHAN LAKEDA SCI & TECH CO LTD
- Filing Date
- 2025-06-27
- Publication Date
- 2026-06-12
AI Technical Summary
Existing X-band waveguide slot antennas have high sidelobes, making it difficult to meet the requirements of more complex electromagnetic environments, and their fabrication and debugging are also highly complex.
By optimizing the tilt angle and cutting depth of the gaps, and adopting Taylor weighted distribution, the energy distribution of each gap is reduced. Combined with symmetrical structural design, cross-polarization is reduced. Integrated machining using CNC machine tools improves machining accuracy and assembly efficiency.
This study achieved a waveguide slot antenna design with low sidelobes, high gain, and low loss, reducing fabrication difficulty and debugging complexity while improving antenna performance.
Smart Images
Figure CN224355446U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of antennas, and specifically relates to an X-band low sidelobe waveguide slot antenna. Background Technology
[0002] With the development of electronic information technology, the working environment of wireless communication equipment is becoming increasingly harsh. To ensure the normal operation of wireless communication equipment, higher requirements are placed on the performance indicators of antennas, such as low sidelobes and high gain. Waveguide slot antennas, by cutting regularly spaced slots on the surface of the waveguide cavity, can achieve performance indicators such as low sidelobes, high gain, and narrow beamwidth. Therefore, waveguide antennas are widely used in airborne, shipborne, and navigation and detection radar systems.
[0003] Chinese utility model patents "A Low Sidelobe X-band Waveguide Slot Array Antenna" (application number: CN202411600116.9) and "An X-band Anti-UAV Radar Waveguide Slot Antenna" (application number: CN202322629752.1) both achieve high-performance waveguide slot antennas with low sidelobes and high gain, but their sidelobes are all greater than -30dB. In order to cope with the more complex electromagnetic environment, designing an antenna system with lower sidelobes has a great positive effect on improving the overall technical performance of the radar. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides an X-band low-sidelobe waveguide slot antenna. By optimizing the tilt angle and insertion depth of the antenna slot, this invention achieves a waveguide slot antenna design with low sidelobes, high gain, low loss, and low coupling. This not only improves antenna performance but also reduces the fabrication difficulty and debugging complexity to some extent.
[0005] The technical solution of this utility model is: an X-band low sidelobe waveguide slot antenna, comprising a waveguide slot antenna array, the waveguide slot antenna array comprising multiple rows of waveguide slot subarray antennas, the center distance between two rows of waveguide slot subarray antennas being 17mm, characterized in that the input end of the waveguide slot antenna is connected to a waveguide coaxial converter; the output end of the waveguide slot antenna is connected to a waveguide load; the wide side dimension of the waveguide cavity is 22.86mm, the narrow side dimension of the waveguide cavity is 10.16mm; each row of waveguide slot subarray antennas comprises multiple slots, each slot having a different tilt angle and cutting depth, the distance between two slots being 24mm; the slots processed on adjacent rows of waveguide slot antennas have a symmetrical structure.
[0006] According to the X-band low sidelobe waveguide slot antenna described above, the characteristic is that the waveguide slot antenna has 8 rows.
[0007] According to the X-band low sidelobe waveguide slot antenna described above, the feature is that the waveguide slot antenna array is made of aluminum and the surface is subjected to conductive oxidation treatment.
[0008] According to the X-band low sidelobe waveguide slot antenna described above, the characteristic is that the number of slots in each row of waveguide slot subarray antennas is 83.
[0009] According to the X-band low sidelobe waveguide slot antenna described above, the characteristics are: the tilt angle of the slot is 0.5°~15.5°, the cutting depth is 3.26mm~3.38mm, and the energy radiated by each slot is distributed according to Taylor weighting.
[0010] According to the X-band low sidelobe waveguide slot antenna described above, the center-to-center distance between any two slots on the same waveguide slot subarray antenna is 24 mm.
[0011] The beneficial effects of this invention are as follows: The antenna adopts an integrated design, transmitting electromagnetic waves through a rectangular waveguide. Energy radiation is achieved by cutting slots on the narrow side of the waveguide. By changing the tilt angle and cutting depth of the slots, the antenna radiation conforms to a specified amplitude distribution, achieving amplitude weighting in the E-plane and reducing antenna sidelobes. Since the electromagnetic waves propagate in the waveguide using air as the medium, losses are low, resulting in high gain for this waveguide slot antenna. The symmetrical angular distribution of adjacent rows of slot antennas reduces cross-polarization phenomena in the antenna array, further suppressing cross-polarization lobes. The antenna array is machined using a CNC machine tool, improving machining accuracy and assembly efficiency. The antenna input is connected to a waveguide-coaxial converter for easy connection to T / R components; the output is connected to a waveguide load to absorb residual radiated energy, reducing reflections and ensuring the antenna's radiation and voltage standing wave ratio performance. Attached Figure Description
[0012] Figure 1 This is a schematic diagram of the three-dimensional structure of an X-band low sidelobe waveguide slot antenna.
[0013] Figure 2 This is a top view schematic diagram of the X-band low sidelobe waveguide slot antenna structure.
[0014] Figure 3 for Figure 2 A partial schematic diagram.
[0015] Figure 4 This is a schematic diagram of the input end of an X-band low sidelobe waveguide slot antenna.
[0016] Figure 5 This is a diagram showing the Taylor weighting coefficient distribution of each slot in the X-band low sidelobe waveguide slot antenna subarray.
[0017] Figure 6 This is a diagram showing the normalized conductance distribution of each slot in the Taylor weighted subarray antenna of the X-band low sidelobe waveguide slot antenna.
[0018] Figure 7 This is a diagram showing the tilt angle distribution of each slot in the X-band low sidelobe waveguide slot antenna subarray.
[0019] Figure 8 This is a diagram showing the cut-in depth distribution of each slot in the X-band low sidelobe waveguide slot antenna subarray.
[0020] Figure 9 The voltage standing wave ratio (VSWR) of the X-band low sidelobe waveguide slot antenna.
[0021] Figure 10 The E-plane radiation pattern of an X-band low-sidelobe waveguide slot antenna with constant amplitude excitation at the center frequency.
[0022] Explanation of reference numerals in the attached figures: 1. Waveguide slot antenna array; 2. Waveguide slot subarray antenna; 3. Waveguide slot antenna input end; 4. Waveguide slot antenna load end; 5. Slot; 7. Narrow side of waveguide cavity; 8. Wide side of waveguide cavity. Detailed Implementation
[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0024] The X-band low sidelobe waveguide slot antenna of this invention is applicable to the frequency band of 9.3GHz~9.7GHz. For example... Figure 1 and Figure 2 As shown, the X-band low-sidelobe waveguide slot antenna array 1 of this invention comprises 8 rows of waveguide slot subarray antennas 2, wherein the center-to-center distance between any two rows of waveguide slot subarray antennas 2 is 17mm. The waveguide slot antenna array 1 is machined from aluminum parts with a conductive oxidation treatment to enhance the transmission performance of microwave signals, reduce electromagnetic wave transmission loss on the aluminum surface, and provide some corrosion resistance. The waveguide slot antenna array 1 is machined using a CNC machine tool, ensuring the machining accuracy of the narrow side slots 5 and guaranteeing antenna performance. Waveguide slot antenna input terminals 3 and load terminals 4 are respectively provided on both sides of the waveguide slot antenna array 1. The waveguide slot antenna input terminal 3 is connected to a waveguide coaxial converter connector for easy connection between the antenna and the back-end T / R assembly; the waveguide slot antenna load terminal 4 is connected to a waveguide load, which absorbs energy that is not radiated through the slots, preventing energy reflection from causing a decrease in antenna radiation and voltage standing wave ratio performance. Simulation results show that... Figure 9 and Figure 10 The in-band voltage standing wave ratio of the antenna is less than 1.1, and the sidelobe level at the center frequency is -33.7dB.
[0025] like Figure 2As shown, each waveguide slot subarray antenna 2 is designed with 83 slots 5, where the first slot on the right side of the input end 3 is numbered 1, and the last slot on the left side of the load end 4 is numbered 83. The energy radiated by each slot 5 is as follows: Figure 5 The Taylor weighted distribution shown is based on the formula. Where i represents the gap number, g i E represents the normalized conductance of the i-th slot, N represents the total number of slots in the subarray antenna, and E i Let represent the Taylor weighting coefficient of the i-th slot, q represent the waveguide loss constant, and η represent the radiation efficiency of the waveguide slot antenna. In this embodiment, q=1, meaning the waveguide is lossless; η=92%, meaning the radiation efficiency of the waveguide slot antenna is 92%. Figure 5 The Taylor weighted coefficient distribution of each slit 5 shown can be used to calculate the normalized conductivity distribution of each slit 5, as follows: Figure 6 As shown. Each slot 5 of the waveguide slot antenna is arranged according to... Figure 5 The normalized conductance distribution shown can achieve lower sidelobes, such as... Figure 10 As shown, the center frequency sidelobe level in this embodiment is -33.7dB, achieving a lower sidelobe level.
[0026] like Figure 3 As shown, the tilt angle θ of the slot 5 is defined as the angle formed by the slot 5 relative to the vertical direction of the waveguide slot subarray antenna 2.
[0027] like Figure 7 and Figure 8 As shown, to achieve the conductivity of each gap 5, it is as follows: Figure 5 As shown in the Taylor weighted distribution, the tilt angle and penetration depth of each slit 5 are different. The tilt angle distribution of each slit 5 is as follows: Figure 7 As shown, the tilt angle of slit 5 ranges from 0.5° to 15.5° (see Table 1 for details); the cutting depth distribution of each slit 5 is as follows. Figure 8 As shown, the cutting depth of slot 5 ranges from 3.26mm to 3.38mm (see Table 2 for details). The energy radiated from each slot 5 is distributed according to Taylor weighting, achieving amplitude weighting of the antenna and reducing the sidelobe level of the antenna pattern. Figure 7 and Figure 8It can be seen that as the slot moves from input end 3 to load end 4, its tilt angle gradually increases and then decreases, reaching its maximum at the 53rd slot at 15.17°. Correspondingly, the cut-in depth of the slots in the middle part of the slot antenna shows a trend of gradually decreasing and then increasing, with the smallest cut-in depth at slots 49 to 55, all at 3.26mm. The cut-in depth of the slots at both ends of the slot antenna does not change regularly because the coupling between the slots at both ends of the slot antenna differs significantly from the coupling between the slots in the middle part of the slot antenna. In actual design, multiple methods need to be tried. Figure 8 The optimal cut-in depth of the central slot is achieved in this embodiment, as shown in Figure 10, resulting in a sidelobe level of -33.7 dB at the center frequency, thus achieving a lower sidelobe. The spacing between two adjacent slots 5 is 24 mm. The slots 5 fabricated on two adjacent waveguide slot subarray antennas 2 are symmetrical structures, used to suppress the vertically polarized electromagnetic wave components generated by the slots 5, reduce the amplitude of the cross-polarized grating lobes, and improve the overall detection performance of the radar.
[0028] Table 1: Correspondence between gap number and tilt angle (tilt angle unit is °)
[0029] Gap number 1 2 3 4 5 6 7 8 9 10 tilt angle 0.66 0.77 0.94 1.14 1.35 1.58 1.83 2.08 2.35 2.63 Gap number 11 12 13 14 15 16 17 18 19 20 tilt angle 2.92 3.22 3.53 3.85 4.17 4.50 4.83 5.17 5.51 5.86 Gap number 21 22 23 24 25 26 27 28 29 30 tilt angle 6.21 6.56 6.91 7.27 7.62 7.98 8.35 8.71 9.07 9.44 Gap number 31 32 33 34 35 36 37 38 39 40 tilt angle 9.80 10.16 10.52 10.87 11.22 11.56 11.90 12.23 12.55 12.86 Gap number 41 42 43 44 45 46 47 48 49 50 tilt angle 13.16 13.44 13.72 13.97 14.21 14.43 14.63 14.80 14.94 15.05 Gap number 51 52 53 54 55 56 57 58 59 60 tilt angle 15.13 15.17 15.17 15.13 15.05 14.92 14.75 14.53 14.27 13.96 Gap number 61 62 63 64 65 66 67 68 69 70 tilt angle 13.60 13.2 12.75 12.27 11.75 11.20 10.63 10.03 9.42 8.80 Gap number 71 72 73 74 75 76 77 78 79 80 tilt angle 8.19 7.58 6.99 6.43 5.90 5.41 4.96 4.57 4.23 3.95 Gap number 81 82 83 tilt angle 3.74 3.60 3.53
[0030] Table 2: Correspondence between gap number and cutting depth (cutting depth is in mm)
[0031] Gap number 1 2 3 4 5 6 7 8 9 10 Cut depth 3.36 3.36 3.36 3.36 3.35 3.34 3.34 3.33 3.34 3.34 Gap number 11 12 13 14 15 16 17 18 19 20 Cut depth 3.34 3.34 3.34 3.34 3.35 3.36 3.38 3.38 3.38 3.38 Gap number 21 22 23 24 25 26 27 28 29 30 Cut depth 3.38 3.37 3.35 3.35 3.36 3.36 3.36 3.36 3.36 3.36 Gap number 31 32 33 34 35 36 37 38 39 40 Cut depth 3.36 3.35 3.35 3.34 3.34 3.34 3.33 3.33 3.32 3.32 Gap number 41 42 43 44 45 46 47 48 49 50 Cut depth 3.31 3.30 3.30 3.29 3.29 3.28 3.27 3.27 3.26 3.26 Gap number 51 52 53 54 55 56 57 58 59 60 Cut depth 3.26 3.26 3.26 3.26 3.26 3.27 3.27 3.28 3.28 3.29 Gap number 61 62 63 64 65 66 67 68 69 70 Cut depth 3.30 3.31 3.32 3.33 3.33 3.34 3.35 3.36 3.36 3.36 Gap number 71 72 73 74 75 76 77 78 79 80 Cut depth 3.36 3.36 3.35 3.37 3.38 3.38 3.38 3.37 3.35 3.34 Gap number 81 82 83 Cut depth 3.34 3.34 3.34
[0032] like Figure 4 As shown, the narrow side 7 of the waveguide cavity has a size of 10.16 mm, and the wide side 8 of the waveguide cavity has a size of 22.86 mm. The end face of the waveguide cavity is the input end 3 of the waveguide slot antenna. By connecting a waveguide coaxial converter, electromagnetic wave energy can be fed into the waveguide slot antenna array 1.
[0033] This invention involves cutting slits along the narrow edge of a waveguide cavity. By adjusting the slit tilt angle and cutting depth, the energy radiated from each slit is distributed according to Taylor weighting. Through integrated CNC machining, this design can meet the requirements for low sidelobe design of waveguide slot antennas, while reducing antenna processing costs and installation complexity.
Claims
1. An X-band low-sidelobe waveguide slot antenna, comprising an array of 8 rows of waveguide slot subarrays, wherein the center-to-center distance between any two rows of waveguide slot subarrays is 17 mm, and waveguide slot antenna input and load terminals are respectively provided on both sides of the waveguide slot antenna array, wherein the waveguide slot antenna input terminal is terminated with a waveguide coaxial converter connector; and the waveguide slot antenna load terminal is terminated with a waveguide load, characterized in that: The tilt angle of the slots ranges from 0.5° to 15.5°; the cut depth of the slots ranges from 3.26 mm to 3.38 mm; the energy radiated by each slot is distributed according to Taylor weighting; the spacing between two adjacent slots ranges from 24 mm; the slots fabricated on two adjacent waveguide slot subarray antennas are symmetrical structures.
2. The X-band low sidelobe waveguide slot antenna according to claim 1, characterized in that: Each waveguide slot subarray antenna is designed with 83 slots, according to the formula... Where i represents the gap number, g i E represents the normalized conductance of the i-th slot, N represents the total number of slots in the subarray antenna, and E i Let represent the Taylor weighting coefficient of the i-th slot, q represent the loss constant of the waveguide, and η represent the radiation efficiency of the waveguide slot antenna.
3. An X-band low sidelobe waveguide slot antenna according to claim 1 or 2, characterized in that: Each waveguide slot subarray antenna is designed with 83 slots, and the correspondence between the slots and the tilt angle is as follows: 。 4. An X-band low sidelobe waveguide slot antenna according to claim 1 or 2, characterized in that: Each waveguide slot subarray antenna is designed with 83 slots, and the correspondence between the slots and the cutting depth is as follows: 。 5. An X-band low sidelobe waveguide slot antenna according to claim 1 or 2, characterized in that: As the slot moves from the input end of the waveguide slot antenna to the load end, its tilt angle gradually increases and then decreases, and the cutting depth of the slot in the middle part of the slot antenna gradually decreases and then increases.
6. An X-band low sidelobe waveguide slot antenna according to claim 1 or 2, characterized in that: The waveguide slot antenna array is made of aluminum and the surface is treated with conductive oxidation.
7. An X-band low sidelobe waveguide slot antenna according to claim 1 or 2, characterized in that: The waveguide slot antenna array is manufactured as a single piece.
8. An X-band low sidelobe waveguide slot antenna according to claim 1 or 2, characterized in that: Each waveguide slot subarray antenna is designed with 83 slots, with the 53rd slot having the largest tilt angle of 15.17°.
9. An X-band low sidelobe waveguide slot antenna according to claim 1 or 2, characterized in that: Each waveguide slot subarray antenna is designed with 83 slots, and the 49th to 55th slots have a cut depth of 3.26 mm.
10. An X-band low sidelobe waveguide slot antenna according to claim 1 or 2, characterized in that: The narrow side of the waveguide cavity has a dimension of 10.16 mm, and the wide side has a dimension of 22.86 mm. The end face of the waveguide cavity is the input end of the waveguide slot antenna. Electromagnetic wave energy can be fed into the waveguide slot antenna by connecting a waveguide coaxial converter.