A waveguide antenna machining process for millimeter wave radar

Abstract

The application discloses a waveguide antenna processing technology for a millimeter wave radar and belongs to the technical field of millimeter wave radars.The processing technology comprises the following steps: forming a non-metal base material through extrusion processing, and processing a plurality of signal channels on the non-metal base material, wherein each of the signal channels is in a broken line shape, one end of the plurality of signal channels is close to each other, the other end of the plurality of signal channels is parallel and spaced, and the plurality of signal channels all penetrate through the non-metal base material; coating a metal layer on the surface of the non-metal base material, wherein the metal layer is uniformly arranged on the outer surface of the non-metal base material and the inner wall of the signal channels; and performing signal attenuation testing on the waveguide antenna to ensure that the signal attenuation of the waveguide antenna is not more than 1 dB.The waveguide antenna processing technology for the millimeter wave radar provided in the embodiment of the application can not only make the waveguide antenna have the non-metal weight, but also achieve the conductive performance of the metal.

Description

Technical Field

[0001] This invention belongs to the field of millimeter-wave radar technology, specifically relating to a waveguide antenna fabrication process for millimeter-wave radar. Background Technology

[0002] Millimeter-wave radar is a distance measurement technology that uses microwave pulses or signals within a specific wavelength range (1mm-10mm) to detect target objects. It is mainly used for monitoring the surrounding environment of vehicles such as automobiles, airplanes, and ships. It primarily consists of a radar radome, a signal transceiver system, and a signal processing system. The signal transceiver system includes a chip and a waveguide antenna. The high-frequency microwave signal generated by the oscillator on the chip is amplified by the transmitting circuit and radiated through the waveguide antenna. These signals are reflected after transmission and return to the millimeter-wave radar.

[0003] However, traditional millimeter-wave radars are made directly from die-cast metal, which is heavy and expensive, while using hybrid materials often results in signal attenuation that does not meet factory requirements. Summary of the Invention

[0004] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a waveguide antenna processing technology for millimeter-wave radar. The purpose is to enable the waveguide antenna to not only have non-metallic weight, but also achieve the conductivity of metal, to complete signal transmission and reception, and to effectively ensure that the signal attenuation meets the factory requirements.

[0005] This invention provides a waveguide antenna fabrication process for millimeter-wave radar, the fabrication process comprising:

[0006] A non-metallic substrate is formed by extrusion, and multiple signal channels are processed on the non-metallic substrate. Each signal channel is zigzag-shaped, with one end of each signal channel close to each other and the other ends of each signal channel parallel and spaced apart. All of the signal channels penetrate the non-metallic substrate.

[0007] A metal layer is coated on the surface of the non-metallic substrate, and the metal layer is uniformly arranged on the outer surface of the non-metallic substrate and the inner wall of the signal channel to obtain a waveguide antenna.

[0008] The waveguide antenna is subjected to a signal attenuation test to ensure that the signal attenuation of the waveguide antenna does not exceed 1dB.

[0009] Optionally, the non-metallic substrate is made of a mixture of polyphenylene sulfide and glass fiber, polyoxymethylene, dodecyl lactam, or acrylonitrile-butadiene-styrene copolymer.

[0010] Optionally, the mass fraction of polyphenylene sulfide in the mixture is 60-90%, and the mass fraction of glass fiber in the mixture is 10-40%.

[0011] Optionally, the metal layer is made of copper, nickel, or silver.

[0012] Optionally, the thickness of the metal layer on the non-metallic substrate is 10-20 μm.

[0013] Optionally, the step of coating the non-metallic substrate surface with a metal layer includes:

[0014] The non-metallic substrate was cleaned with pure water.

[0015] The non-metallic substrate is placed in an aqueous solution for water leaching.

[0016] Optionally, the aqueous solution includes a copper salt solution, a complexing agent, a pH buffer, a stabilizer, and an activator.

[0017] Optionally, after coating the non-metallic substrate with a metal layer, the processing further includes:

[0018] Nano-colored oil is sprayed multiple times onto the surface of the waveguide antenna, and the surface remains stationary for a unit of time between each two consecutive sprayings.

[0019] Optionally, each of the signal channels includes an entry segment, a connection segment, and an exit segment. The entry segment and the exit segment are arranged in parallel and spaced apart. The connection segment is located within the non-metallic substrate, and the two ends of the connection segment are respectively connected to one end of the entry segment and one end of the exit segment.

[0020] Optionally, each of the signal channels has a tapered structure, and the size of the small end of the signal channel is 2.5*1.1-3.0*1.5mm.

[0021] In summary, the beneficial effects of the above-described technical solutions conceived by this invention compared with the prior art include:

[0022] The waveguide antenna fabrication process for millimeter-wave radar provided in this embodiment of the invention involves the following steps: First, a non-metallic substrate is formed through extrusion. Multiple signal channels are then fabricated on this substrate, each channel being a zigzag shape. One end of each channel is close to the others, while the other ends are parallel and spaced apart. All signal channels penetrate the non-metallic substrate. Because the non-metallic substrate is lightweight, low-cost, and easy to fabricate, it meets both weight and cost requirements. Next, a metal layer is coated onto the surface of the non-metallic substrate. This metal layer is evenly distributed on the outer surface of the substrate and the inner walls of the signal channels, thus obtaining the waveguide antenna. This allows the waveguide antenna to have the weight of a non-metallic substrate internally while achieving the conductivity of a metal externally. Millimeter waves can then transmit and receive signals through the signal channels. Finally, a signal attenuation test is performed on the waveguide antenna to ensure that the signal attenuation does not exceed 1 dB, thereby reducing millimeter-wave transmission loss and meeting the factory requirements for the waveguide antenna.

[0023] In other words, the waveguide antenna fabrication process for millimeter-wave radar provided by the embodiments of the present invention enables the waveguide antenna to not only have non-metallic weight but also achieve the conductivity of metal, enabling it to transmit and receive signals, and effectively ensuring that the signal attenuation meets the factory requirements. Attached Figure Description

[0024] Figure 1 This is a flowchart of a waveguide antenna fabrication process for millimeter-wave radar provided in an embodiment of the present invention;

[0025] Figure 2 This is a cross-sectional view of the waveguide antenna provided in an embodiment of the present invention.

[0026] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically:

[0027] 1. Non-metallic substrate; 2. Signal channel; 21. Inlet section; 22. Connecting section; 23. Outlet section; 3. Metallic layer. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0029] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0031] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0032] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0033] Example:

[0034] Figure 1 This is a flowchart illustrating a waveguide antenna fabrication process for millimeter-wave radar, as provided in an embodiment of the present invention. Figure 1 As shown, the processing technology includes:

[0035] S1. A non-metallic substrate 1 is formed by extrusion, and multiple signal channels 2 are processed on the non-metallic substrate 1. Each signal channel 2 is a zigzag shape. One end of the multiple signal channels 2 is close to each other, and the other ends of the multiple signal channels 2 are parallel and spaced apart. All the multiple signal channels 2 penetrate the non-metallic substrate 1 (see...). Figure 2 ).

[0036] S2. A metal layer 3 is coated on the surface of the non-metallic substrate 1. The metal layer 3 is evenly distributed on the outer surface of the non-metallic substrate 1 and the inner wall of the signal channel 2, thereby obtaining a waveguide antenna.

[0037] S3. Perform a signal attenuation test on the waveguide antenna to ensure that the signal attenuation of the waveguide antenna does not exceed 1dB.

[0038] In the waveguide antenna fabrication process for millimeter-wave radar provided in this embodiment of the invention, the waveguide antenna is fabricated by first forming a non-metallic substrate 1 through extrusion, and then fabricating multiple signal channels 2 on the non-metallic substrate 1. Each signal channel 2 is a zigzag shape, with one end of each signal channel 2 close to each other and the other ends parallel and spaced apart, and all signal channels 2 penetrating the non-metallic substrate 1. Because the non-metallic substrate 1 is lightweight, low-cost, and easy to fabricate, it meets both weight and cost requirements. Next, a metal layer 3 is coated on the surface of the non-metallic substrate 1, uniformly distributed on the outer surface of the non-metallic substrate 1 and the inner wall of the signal channels 2, thus obtaining the waveguide antenna. This allows the waveguide antenna to have the weight of the non-metallic substrate 1 internally while achieving the conductivity of a metal externally, enabling millimeter waves to transmit and receive signals through the signal channels 2. Finally, a signal attenuation test is performed on the waveguide antenna to ensure that the signal attenuation does not exceed 1 dB, thereby reducing millimeter-wave transmission loss and meeting the factory requirements for the waveguide antenna.

[0039] In other words, the waveguide antenna fabrication process for millimeter-wave radar provided by the embodiments of the present invention enables the waveguide antenna to not only have non-metallic weight but also achieve the conductivity of metal, enabling it to transmit and receive signals, and effectively ensuring that the signal attenuation meets the factory requirements.

[0040] Furthermore, since each signal channel 2 is a zigzag shape, with one end of multiple signal channels 2 close to each other and the other ends of multiple signal channels 2 parallel and spaced apart, and all multiple signal channels 2 penetrating the non-metallic substrate 1, on the one hand, the signal transmitting end and receiving end (the top of the signal channel 2) are concentrated in one place as much as possible to facilitate chip processing (the top of the signal channel 2 is directly opposite the chip's transceiver position). On the other hand, the signal transmitting and receiving ends (the bottom of the signal channel 2) need to be divergent (i.e., the interval between one end of multiple signal channels 2 is much smaller than the interval between the other ends of multiple signal channels 2) to avoid interference and ensure the accuracy of signal processing; therefore, it needs to be made into a zigzag shape.

[0041] For example, the number of signal channels 2 can be 8, of which 4 are signal input channels and 4 are signal output channels.

[0042] In this embodiment, the non-metallic substrate 1 can be a mixture of polyphenylene sulfide (PPS) and glass fiber, polyoxymethylene (POM), dodecyl lactam (PA12), or acrylonitrile-butadiene-styrene copolymer (ABS).

[0043] The surface resistivity of the aforementioned non-metallic substrates 1 is low, and the signal attenuation is less than 1 dB. Furthermore, the aforementioned non-metallic substrates 1 possess high strength, allowing the waveguide antenna to meet mechanical performance requirements while also possessing the weight and heat resistance of a non-metallic material.

[0044] Table 1 shows the relevant performance and signal attenuation of different non-metallic substrates 1, as shown in Table 1:

[0045] Non-metallic substrate 1 Surface resistance cost Metal layer 3 Signal attenuation strength PPS + Glass Fiber <![CDATA[10 6 Ω and above Low copper Less than 1dB suitable POM <![CDATA[10 3 -10 6 Ω and above middle copper Less than 1dB Easy to crack PA12 <![CDATA[10 2 Below Ω high copper Less than 1dB Easy to crack ABS <![CDATA[10 6 Ω and above Low copper Less than 1dB suitable PBT <![CDATA[10 2 Oh]]> high copper Less than 1dB Easily broken

[0046] Table 1

[0047] It should be noted that while PBT (thermoplastic polyester) is easy to mold and has high strength, it is highly environmentally sensitive, brittle, and extremely sensitive to notches, exhibiting breakage during the processing of complex mechanisms; therefore, it was excluded. PA12 and POM are also prone to cracking and were excluded. Furthermore, traditional engineering plastic antenna substrates typically use ABS, but this antenna, used in automobiles, needs to meet 120°C high-temperature aging verification conditions, while ABS's heat resistance temperature is -100°C, failing to meet the temperature resistance requirements. In comparison, PPS can be used for extended periods at 220-240°C. Moreover, since the waveguide antenna experiences bumps and vibrations during vehicle movement, conventional PPS, being relatively brittle, is at risk of deformation and breakage of signal channel 2 after prolonged exposure to vibrations, affecting signal transmission efficiency. To further improve substrate performance and enhance the impact resistance of the parts, PPS + glass fiber was selected to improve the mechanical properties of the parts.

[0048] Therefore, in summary, the non-metallic substrate 1 is preferably a mixture of polyphenylene sulfide (PPS) and glass fiber.

[0049] In this embodiment, the mass fraction of polyphenylene sulfide in the mixture is 60-90%, and the mass fraction of glass fiber in the mixture is 10-40%.

[0050] It is easy to understand that if the glass fiber content is too high, the toughness will be reduced. Therefore, the mass fraction of polyphenylene sulfide in the mixture is selected to be 60-90%, and the mass fraction of glass fiber in the mixture is 10-40%. Preferably, PPS + 40% glass fiber is used as the final non-metallic substrate 1.

[0051] Furthermore, the material of metal layer 3 is copper, nickel, or silver.

[0052] Table 2 shows the relevant performance and signal attenuation of different metal layers 3.

[0053] Metal layer 3 Surface resistance roughness Signal attenuation nickel 1.054MΩ 1.054 0.6dB silver 4.08MΩ 1.319 1dB copper 4.57MΩ 2.676 0.5dB

[0054] Table 2

[0055] It's easy to understand that silver plating has higher batch costs, resulting in a very thin plating layer. Furthermore, silver itself is soft, typically around 0.5-2 micrometers in diameter, and cannot withstand friction, which poses a risk of wear to waveguide antennas during use. Nickel particles, on the other hand, pose a risk of gaps in complex structures, exhibiting porosity. This leads to poor high-frequency electromagnetic wave shielding, and in marine or humid environments, subsequent salt spray tests may show corrosion of the substrate. Copper, however, has good ductility, does not peel or bubble after plating, and is more dense and uniform; therefore, copper is the preferred metal layer.

[0056] In this embodiment, step S2 includes:

[0057] S21. Clean the non-metallic substrate 1 with pure water.

[0058] In the above embodiments, cleaning the non-metallic substrate 1 with pure water can ensure the cleanliness of the surface of the non-metallic substrate 1, which facilitates the subsequent application of the metal layer 3.

[0059] After step S21, the processing technology may further include: degreasing, roughening, neutralizing, activating and acidifying the non-metallic substrate 1.

[0060] Specifically, degreasing: removing oil stains from the surface of the non-metallic substrate 1.

[0061] Roughening: Makes the surface of the non-metallic substrate 1 rougher, thereby improving the adhesion between the surface of the non-metallic substrate 1 and the metal layer 3.

[0062] Neutralization: Removes ions remaining after coarsening.

[0063] Activation: Catalyze the surface of non-metallic substrate 1 to form a metal layer 3.

[0064] Acidification: Removes the surface oxide film.

[0065] S22. Place the non-metallic substrate 1 in the aqueous solution and perform aqueous plating on the non-metallic substrate 1.

[0066] In the above embodiments, water plating can increase the bonding strength between the metal layer 3 and the non-metallic substrate 1, allowing the metal layer 3 and the non-metallic layer 3 to bond into an alloy, thus greatly enhancing their bonding ability. Furthermore, after water plating, the metal layer 3 is more uniform, and the signal loss is less than 1 dB for different types of coatings.

[0067] It should be noted that, using a spray coating process, the signal channel 2 is too small to be properly coated, resulting in a signal loss of over 30dB. Furthermore, using a vacuum coating process, the bonding strength between the metal layer 3 and the non-metallic substrate 1 is low, making the metal layer 3 extremely prone to detachment.

[0068] For example, the aqueous solution includes a copper salt solution, a complexing agent, a pH buffer, a stabilizer, and an activator.

[0069] The copper salt solution forms a copper plating layer that adheres to the substrate. This copper salt solution can be copper sulfate, copper chloride, or sodium sulfate.

[0070] Coordinating agent: generates the cathode electrochemical electrode.

[0071] pH buffer: It keeps the pH of the plating solution or cathode interface relatively stable, so that it does not change too quickly and exceed the range allowed by the process.

[0072] Stabilizer: Prevents oxidation of the main salt.

[0073] Activator: Substances that eliminate or reduce anodic polarization, promote normal anodic dissolution, and increase anodic current density.

[0074] Furthermore, after step S2, the processing technology also includes:

[0075] Nano-colored oil is sprayed multiple times on the surface of the waveguide antenna, and the surface remains stationary for a unit of time between each two sprayings.

[0076] In the above embodiments, the nano-color oil can protect the metal layer 3 and prevent the metal layer 3 from oxidizing.

[0077] Furthermore, the thickness of the metal layer 3 on the non-metallic substrate 1 is 10-20 μm.

[0078] Table 3 shows the relevant performance and signal attenuation of metal layer 3 with different thicknesses when copper is used as the metal layer 3 and the coating process is water-coating.

[0079] Metal layer thickness Signal attenuation Uniformity 20um 0.5dB better 15um 0.4dB better 10um 0.7dB better 5um 0.3dB Poor

[0080] Table 3

[0081] Therefore, different coating thicknesses can meet the usage requirements. Considering both cost and coating uniformity, 10um-20um is selected as the final product coating thickness.

[0082] See you again Figure 2 Each signal channel 2 includes an inlet section 21, a connecting section 22, and an outlet section 23. The inlet section 21 and the outlet section 23 are arranged in parallel and spaced apart. The connecting section 22 is located in the non-metallic substrate 1, and the two ends of the connecting section 22 are respectively connected to one end of the inlet section 21 and one end of the outlet section 23.

[0083] In the above embodiment, the signal channel 2 is bent by the connecting section 22, and the exit section 23 and the entrance section 21 are staggered so that the signal transmitting end and the receiving end are concentrated in one place as much as possible, while the signal transmitting end and the signal receiving end are dispersed.

[0084] It should be noted that the non-metallic substrate 1 can be two opposing plates (each plate has a groove), and the two opposing grooves can be connected to form a signal channel 2, which facilitates the processing of the signal channel 2.

[0085] For example, each signal channel 2 has a tapered structure, and the size of the small end of the signal channel 2 is 2.5*1.1-3.0*1.5mm.

[0086] It should be noted that the small end of signal channel 2 is... Figure 2 At the top of signal channel 2, the large end of signal channel 2 is Figure 2 At the bottom of signal channel 2, from the small end to the large end, the size of signal channel 2 gradually increases.

[0087] Preferably, the size of the small end of signal channel 2 is 2.55*1.15mm.

[0088] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A waveguide antenna fabrication process for millimeter-wave radar, characterized in that, The processing technology includes: A non-metallic substrate is formed by extrusion, and multiple signal channels are processed on the non-metallic substrate. Each signal channel is a zigzag shape. One end of the multiple signal channels is close to each other and is used to face the chip's transceiver position. The other ends of the multiple signal channels are parallel and spaced apart. The interval between one end of the multiple signal channels is smaller than the interval between the other ends of the multiple signal channels, and all of the multiple signal channels penetrate the non-metallic substrate. A metal layer is coated on the surface of the non-metallic substrate, and the metal layer is uniformly arranged on the outer surface of the non-metallic substrate and the inner wall of the signal channel to obtain a waveguide antenna. The waveguide antenna is subjected to a signal attenuation test to ensure that the signal attenuation of the waveguide antenna does not exceed 1dB.

2. The waveguide antenna fabrication process for millimeter-wave radar according to claim 1, characterized in that, The non-metallic substrate is made of a mixture of polyphenylene sulfide and glass fiber, polyoxymethylene, dodecyl lactam, or acrylonitrile-butadiene-styrene copolymer.

3. The waveguide antenna fabrication process for millimeter-wave radar according to claim 2, characterized in that, The mixture contains 60-90% polyphenylene sulfide by mass and 10-40% glass fiber by mass.

4. The waveguide antenna fabrication process for millimeter-wave radar according to claim 1, characterized in that, The metal layer is made of copper, nickel, or silver.

5. The waveguide antenna fabrication process for millimeter-wave radar according to claim 2, characterized in that, The thickness of the metal layer on the non-metallic substrate is 10-20 μm.

6. The waveguide antenna fabrication process for millimeter-wave radar according to claim 1, characterized in that, The process of coating a metal layer on the surface of the non-metallic substrate includes: The non-metallic substrate was cleaned with pure water. The non-metallic substrate is placed in an aqueous solution for water leaching.

7. The waveguide antenna fabrication process for millimeter-wave radar according to claim 6, characterized in that, The aqueous solution includes a copper salt solution, a complexing agent, a pH buffer, a stabilizer, and an activator.

8. The waveguide antenna fabrication process for millimeter-wave radar according to claim 1, characterized in that, After the metal layer is coated on the surface of the non-metallic substrate, the processing technology further includes: Nano-colored oil is sprayed multiple times onto the surface of the waveguide antenna, and the surface remains stationary for a unit of time between each two consecutive sprayings.

9. A waveguide antenna fabrication process for millimeter-wave radar according to any one of claims 1-7, characterized in that, Each of the signal channels includes an inlet section, a connecting section, and an outlet section. The inlet section and the outlet section are arranged in parallel and spaced apart. The connecting section is located within the non-metallic substrate, and the two ends of the connecting section are respectively connected to one end of the inlet section and one end of the outlet section.

10. A waveguide antenna fabrication process for millimeter-wave radar according to any one of claims 1-7, characterized in that, Each of the signal channels has a tapered structure, and the size of the small end of the signal channel is 2.5*1.1-3.0*1.5mm.

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