Method for trimming beam pointing of dual-polarized waveguide traveling wave antenna through film loading
By loading a transparent film onto the outer surface of a dual-polarized waveguide traveling wave antenna and adjusting the transmission phase on the slot, the problem of inconsistent beam pointing of pre-fabricated waveguide traveling wave antennas was solved, achieving high-precision beam pointing consistency and improving the radar's detection capability.
Patent Information
- Application Number
- CN202511320389.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-16
- Publication Date
- 2025-12-12
AI Technical Summary
The lack of existing technology for beam pointing consistency adjustment of pre-fabricated dual-polarized waveguide traveling wave antennas affects the data quality and reliability of dual-polarized phased array radars.
By loading a transparent thin film onto the outer surface of the waveguide traveling wave antenna, the dielectric constant of the film is used to change the additional transmission phase on the slot, thereby adjusting the beam pointing so that it is consistent with the beam pointing of another polarized waveguide. Polyimide film is used as the material, and the film thickness is obtained in advance through electromagnetic simulation and adjusted layer by layer until the accuracy requirements are met.
It achieves high-precision consistency correction of dual-polarized beam pointing, improves the system detection capability of dual-polarized phased array radar, and the method is easy to implement in engineering and has low cost.
Smart Images
Figure CN121123633A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of microwave antennas, in particular to a method for adjusting the beam pointing of a dual-polarized waveguide traveling-wave antenna loaded with a thin film. BACKGROUND
[0002] Dual-polarized waveguide traveling-wave antennas (such as shown in Figure 1 ) are widely used in dual-polarized phased array radars. Waveguide traveling-wave antennas are antennas that produce electromagnetic radiation outside the waveguide through the slots on the surface of the waveguide. They have the advantages of small size, high gain, low sidelobe, compact structure, large power capacity, high radiation efficiency, low cross-polarization level, and low cost. However, waveguide traveling-wave antennas have a natural disadvantage, which is the existence of beam pointing bias angle, i.e., the maximum pointing of the beam is offset from the normal direction. There is often a certain inconsistency in the pointing of the two polarizations of the dual-polarized waveguide traveling-wave antenna. This inconsistency has a certain impact on dual-polarized phased array radars, especially on dual-polarized phased array weather radars that measure body targets. The inconsistency in pointing has a particularly significant impact on weather observation quality.
[0003] Dual-polarized phased array weather radars can obtain more rich meteorological target information by simultaneously transmitting and receiving electromagnetic waves in horizontal and vertical polarization directions. The consistency of the pointing of the two polarized beams is the cornerstone of the data quality of the radar, and it directly affects the performance of precipitation type identification, rainfall measurement accuracy, ground clutter suppression, and extreme antenna warning reliability. Therefore, to ensure the accuracy and reliability of radar detection data, dual-polarized weather radars require the pointing of the two polarized beams to be strictly consistent, i.e., the horizontal polarization and vertical polarization beams must illuminate the same batch of meteorological targets at the same time to ensure the consistency of spatial sampling.
[0004] For dual-polarized waveguide traveling-wave antennas, the radiation mechanism determines that the beam pointing is offset from the normal direction. By adjusting the waveguide size, slot spacing, etc., the beam deflection angle can be controlled to ensure that the two polarized beams point in the same direction. However, in engineering practice, the pointing of the dual-polarized waveguide traveling-wave antenna may deviate from the theoretical expectation due to design, manufacturing, and environmental factors. (As shown in Figure 2 Common causes of deviation include machining errors, welding deformation, metal thermal expansion and contraction, etc. In dual-polarized waveguide traveling-wave antennas, the two polarized waveguides are different in form and difficulty of processing, and the degree of deviation from the expected pointing is inconsistent, resulting in deviation in the pointing of the two polarized beams.
[0005] However, there is currently a technical gap in the existing technology, as there is a lack of methods for adjusting the consistency of the pointing of dual-polarized waveguide traveling-wave antennas that have been processed and shaped. SUMMARY
[0006] In view of the problems in the prior art, the application provides a method for simply and easily operating, easily implementing engineering and adjusting the beam pointing consistency of a dual-polarized waveguide traveling wave antenna, especially for the dual-polarized waveguide traveling wave antenna with inconsistent pointing after being processed and formed, so as to ensure that the dual-polarized beams meet the precision requirement of the pointing consistency and improve the system detection capability of the dual-polarized phased array radar.
[0007] The object of the application is achieved by the following technical solutions.
[0008] A method for adjusting the beam pointing of a dual-polarized waveguide traveling wave antenna by loading a film, comprising the following steps:
[0009] Step S1: obtaining the thickness of the film to be loaded on the outer surface of the waveguide traveling wave antenna in advance;
[0010] Step S2: loading a wave-transparent film on the outer surface of the waveguide traveling wave antenna for the polarization with a smaller deviation angle in the dual polarization, changing the additional transmission phase on each gap of the waveguide traveling wave antenna through the influence of the dielectric constant of the film, thereby increasing the beam pointing of the waveguide traveling wave antenna corresponding to the polarization, and making the beam pointing of the waveguide traveling wave antenna corresponding to the other polarization tend to be consistent.
[0011] Further, step S1 specifically comprises: accumulating the film on the corresponding polarization waveguide to be loaded with the film by using an electromagnetic simulation software, adjusting the thickness parameter of the film, simulating the pointing change of the dual-polarized waveguide traveling wave antenna, and obtaining the thickness of the film to be loaded in advance.
[0012] Further, the thickness parameter of the film is three layers of film, and the beam pointing angle changed by the three layers of film is about 0.25 degrees within the X-band 9.3GHz-9.5GHz bandwidth, so that the correction effect of the beam pointing consistency can be realized within ±0.04 degrees, and sufficient precision is achieved.
[0013] Further, step S2 specifically comprises: testing the dual-polarized waveguide traveling wave antenna after loading each layer of film, verifying the precision of the pointing consistency, and repeating the above steps until the thickness close to the electromagnetic simulation is achieved and the precision requirement of the beam pointing consistency is met.
[0014] Further, the film material is polyimide.
[0015] Further, the relative dielectric constant (εr) of the polyimide film is about 3.3, and the electric loss tangent (tanδ) is about 0.03.
[0016] Further, the polyimide film is a single-layer film with a thickness of 65μm and a back adhesive polyimide tape.
[0017] Compared with the prior art, the application has the following advantages:
[0018] (1) Through the way of thin film loading, without changing the internal structure of waveguide, easy to engineering implementation;
[0019] (2) The material of surface thin film is polyimide film, which is resistant to high temperature and not easy to decompose (600℃ can begin to decompose); the molecular chain has strong rigidity and small free volume, and is not easy to penetrate; it has excellent high temperature resistance, chemical stability and mechanical properties; its relative dielectric constant (εr) is about 3.3, the conductive loss tangent (tanδ) is about 0.03, and the thickness can be made to μm level, which is a kind of electromagnetic material with better performance. Such as polyimide tape with adhesive, which is commonly used in the market, easy to purchase and low cost;
[0020] (3) Higher consistency accuracy of dual-polarized wave beam pointing can be obtained by thin film loading. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 It is a schematic diagram of the dual-polarized waveguide traveling wave antenna.
[0022] Figure 2 It is a schematic diagram of the frequency offset beam pointing of the dual-polarized waveguide traveling wave antenna (without thin film loading).
[0023] Figure 3 It is a schematic diagram of the dual-polarized waveguide traveling wave antenna (horizontal polarization waveguide thin film loading).
[0024] Figure 4 It is a schematic diagram of the frequency offset beam pointing of the dual-polarized waveguide traveling wave antenna (thin film loading after adjustment).
[0025] Figure 5 It is a schematic diagram of the beam pointing angle of the dual-polarized waveguide traveling wave antenna (unmodified effect within the bandwidth).
[0026] Figure 6 It is a schematic diagram of the beam pointing angle of the dual-polarized waveguide traveling wave antenna (modified effect within the bandwidth, single layer film).
[0027] Figure 7 It is a schematic diagram of the beam pointing angle of the dual-polarized waveguide traveling wave antenna (modified effect within the bandwidth, three layer film). DETAILED DESCRIPTION
[0028] The present application will be described in detail below in conjunction with the drawings and specific examples of the specification.
[0029] (1) Mechanism analysis
[0030] The invention introduces a film loading method to adjust the pointing of the waveguide traveling wave antenna, and make the pointing of the dual-polarized waveguide traveling wave antenna consistent. Especially for the waveguide traveling wave antenna that has been processed and has the problem of inconsistent dual-polarized beam pointing. For the polarization with a small deviation angle (the angle deviated from the normal) in the dual-polarization, taking the horizontal polarization as an example, a wave-transparent film (such as Figure 3 ) with a thickness meeting the pointing requirement is loaded on the outer surface of the horizontal polarization waveguide, the additional transmission phase on each slot of the horizontal polarization waveguide traveling wave array is changed by the influence of the dielectric constant of the film, so that the pointing deviation angle of the horizontal polarization waveguide traveling wave array is increased, the beam pointing of the horizontal polarization waveguide traveling wave array is close to the beam pointing of the vertical polarization waveguide slot traveling wave array, and the beam pointing difference between the two polarizations is reduced (as shown in Figure 4 ). Through practice test, the method is effective for horizontal and vertical polarization waveguide traveling wave antennas.
[0031] (2) Electromagnetic simulation
[0032] The thickness of the film required for loading can be obtained in advance through electromagnetic simulation. Through electromagnetic simulation software, a layer of film is added to the corresponding polarization waveguide that needs film loading, the film thickness parameter is adjusted, and the pointing change of the dual-polarized waveguide traveling wave antenna is simulated. The film thickness parameter obtained by electromagnetic simulation can be used as an important basis for sticking film thickness and adjusting beam pointing in engineering practice.
[0033] (3) Film material selection
[0034] Polyimide (PI) is a cyclic polymer, and is a film material with relatively good performance among many polymers. It contains imide rings in the main chain, is not easy to decompose at high temperature (can only start to decompose at 600°C), has strong molecular chain rigidity and small free volume, is not easy to penetrate, has excellent high-temperature resistance, chemical stability and mechanical properties, has a relative dielectric constant (εr) of about 3.3, a conductive loss tangent (tanδ) of about 0.03, and a thickness of μm level, so it is also an electromagnetic material with relatively good performance. The commonly used in industry is a single-layer polyimide adhesive tape with a thickness of 65 μm, which is convenient to use and is the preferred film material of the invention.
[0035] The thickness of the film required for loading can be obtained in advance through electromagnetic simulation. Through electromagnetic simulation software, a layer of polyimide film is added to the corresponding polarization waveguide that needs film loading, the film thickness parameter is adjusted, and the pointing change of the dual-polarized waveguide traveling wave antenna is simulated. The film thickness parameter obtained by electromagnetic simulation can be used as an important basis for sticking film thickness and adjusting beam pointing in engineering practice.
[0036] Embodiment
[0037] (1) The thickness of the film required for loading is obtained in advance through electromagnetic simulation;
[0038] (2) For the polarized corresponding waveguide with small pointing deviation angle, use the polyimide tape with adhesive on the back to paste the film on the surface;
[0039] (3) Test the dual-polarized waveguide antenna after loading each layer of film, and verify whether there is targeted improvement;
[0040] (4) If the required effect is not achieved, continue to paste the second layer of film according to the above two steps, test the antenna beam pointing difference, and repeat the process until the thickness approaches the electromagnetic simulation and the accuracy requirement of beam pointing consistency is met;
[0041] (5) According to the actual measurement results of a certain product, within the X-band 9.3GHz-9.5GHz bandwidth, the beam pointing angle that can be changed by single-layer film is about 0.08 degrees; the beam pointing angle that can be changed by three-layer film is about 0.25 degrees; and the final correction effect of beam pointing consistency can be achieved within ±0.04 degrees, which has sufficient accuracy (as shown in Figure 5 、 Figure 6 、 Figure 7 ).
Claims
1. A method for adjusting the beam pointing of a dual-polarized waveguide traveling-wave antenna using thin-film loading, characterized in that, Includes the following steps: Step S1: Pre-determine the thickness of the thin film to be loaded on the outer surface of the waveguide traveling wave antenna; Step S2: For the polarization with a smaller deviation angle in the dual polarization, a transparent film is loaded on the outer surface of its waveguide traveling wave antenna. The additional transmission phase on each slot of the waveguide traveling wave array is changed by the influence of the dielectric constant of the film itself, thereby increasing the beam pointing of the waveguide traveling wave antenna corresponding to that polarization, so that it tends to be consistent with the beam pointing of the waveguide traveling wave antenna of the other polarization.
2. The method for adjusting the beam pointing of a dual-polarized waveguide traveling-wave antenna by thin-film loading according to claim 1, characterized in that, Step S1 specifically includes: Using electromagnetic simulation software, a thin film is added to the corresponding polarized waveguide that requires thin film loading. The film thickness parameters are adjusted to simulate the pointing change of the dual-polarized waveguide traveling wave antenna, so as to obtain the required film loading thickness in advance.
3. The method for adjusting the beam pointing of a dual-polarized waveguide traveling-wave antenna by thin-film loading according to claim 1, characterized in that, The film consists of three layers. Within the X-band bandwidth of 9.3GHz to 9.5GHz, the three layers alter the beam pointing angle by 0.25 degrees, achieving a beam pointing consistency correction effect within ±0.04 degrees.
4. The method for adjusting the beam pointing of a dual-polarized waveguide traveling-wave antenna by thin-film loading according to claim 1, characterized in that, Step S2 specifically includes: Each time a thin film is added, the dual-polarized waveguide traveling wave antenna is tested to verify the accuracy of beam pointing consistency. If the requirements are not met, the above steps are repeated until the thickness is close to that of the electromagnetic simulation and the accuracy requirements of beam pointing consistency are met.
5. A method for adjusting the beam pointing of a thin-film loaded traveling-wave antenna with dual-polarized waveguide according to any one of claims 1 to 4, characterized in that, The film is a polyimide film.
6. The method for adjusting the beam pointing of a dual-polarized waveguide traveling-wave antenna by thin-film loading according to claim 5, characterized in that, The polyimide film has a relative permittivity of 3.3 and a conductive loss tangent of 0.
03.
7. The method for adjusting the beam pointing of a dual-polarized waveguide traveling-wave antenna by thin-film loading according to claim 6, characterized in that, The polyimide film is a single-layer polyimide tape with an adhesive backing and a thickness of 65 μm.