An optimized PCB circuit structure for automotive 77GHz millimeter-wave radar

Abstract

This invention provides an optimized PCB circuit structure for a 77GHz millimeter-wave radar for automobiles. The PCB includes a circuit layer with a plating layer and an insulating dielectric layer covering it. The circuit layer also features corner structures, with at least one corner structure. This invention reduces signal transmission loss by reducing the surface roughness of the circuit layer through chemical polishing. Combined with a nanoscale insulating dielectric layer, it reduces scattering and dielectric losses during signal transmission. At 77GHz, signal transmission loss is reduced by 20%-30% compared to traditional processes, significantly improving signal transmission efficiency and increasing radar detection range and accuracy.

Description

Technical Field

[0001] This utility model belongs to the field of PCB processing technology, and in particular relates to an optimized PCB circuit structure for automotive 77GHz millimeter-wave radar. Background Technology

[0002] The PCB of 77GHz millimeter-wave radar is a core component of automotive radar systems. Currently, there are some issues with the manufacturing process of PCB circuits used in automotive 77GHz millimeter-wave radar.

[0003] For example, a large surface roughness of the circuit leads to additional losses during signal transmission; the right-angle design at the corners of the circuit can easily cause signal reflection, affecting the signal transmission quality; and the poor uniformity of the plating on the circuit reduces the conductivity and oxidation resistance of the circuit, shortening the lifespan of the PCB.

[0004] These issues have all limited the performance improvement of automotive 77GHz millimeter-wave radar. Utility Model Content

[0005] To address the aforementioned technical problems, this utility model provides an optimized PCB circuit structure for automotive 77GHz millimeter-wave radar. By improving the surface finish of the circuit, optimizing the corner design, and enhancing plating uniformity, it reduces signal transmission loss, minimizes signal reflection, and improves circuit conductivity and oxidation resistance, thereby enhancing the performance and lifespan of the PCB.

[0006] This utility model is achieved through the following technical solution:

[0007] An optimized PCB circuit structure for a 77GHz millimeter-wave radar for automobiles includes a PCB board, a circuit layer disposed within the PCB board, a plating layer and an insulating dielectric layer covering the circuit layer, and a corner structure disposed on the circuit layer, with at least one corner structure.

[0008] Preferably, the corner structure adopts a 45° angled corner structure, and the side length of the 45° angled corner is 1.5 times the line width of the line layer.

[0009] Preferably, the corner structure is an arc corner structure, and the radius of the arc is twice the width of the line layer.

[0010] Preferably, the circuit layer is a chemically polished circuit layer with a surface roughness Ra ≤ 0.3 μm.

[0011] Preferably, the coating is processed using a pulse electroplating process, and the thickness uniformity error of the coating is ±5%.

[0012] Preferably, the insulating dielectric layer is a silicon dioxide nanoscale insulating dielectric layer prepared by chemical vapor deposition (CVD) process, and the thickness of the insulating dielectric layer is 50 nm.

[0013] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0014] 1. This invention reduces signal transmission loss by reducing the surface roughness of the circuit layer through chemical polishing and combining it with a nanoscale insulating dielectric layer, thereby reducing scattering loss and dielectric loss during signal transmission. At a frequency of 77GHz, the signal transmission loss can be reduced by 20%-30% compared with traditional processes, significantly improving signal transmission efficiency and increasing the range and accuracy of radar detection.

[0015] 2. This utility model reduces signal reflection; the corner structure 111 is designed to reduce signal reflection.

[0016] The 45° angle or arc effectively avoids the reflection and distortion of high-frequency signals at the corner structure 111, making the signal transmission more stable. Tests have shown that the signal reflection intensity is reduced by about 40%, ensuring the accuracy of radar signal reception and improving the radar system's ability to identify and locate target objects.

[0017] 3. This utility model improves circuit performance and lifespan. The plating layer processed by pulse electroplating combined with a stirring device greatly improves the uniformity of the plating layer, effectively reduces circuit resistance, enhances conductivity, and at the same time, the uniform plating layer can better resist external environmental corrosion and significantly improve oxidation resistance. This extends the service life of the PCB in the complex automotive working environment by about 30%-40%, reduces maintenance and replacement costs, and improves the reliability of automotive radar systems. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of this utility model.

[0019] Figure 2 This is a schematic diagram of the PCB board and point A of this utility model.

[0020] Figure 3 This is a schematic diagram of the structure at point A of this utility model.

[0021] In the picture:

[0022] 1. PCB board; 11. Circuit layer; 111. Corner structure; 12. Plating layer; 13. Insulating dielectric layer. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings, as shown below. Figure 1 To be continued Figure 3As shown, a PCB circuit process optimization structure for a 77GHz millimeter-wave radar for automobiles includes a PCB board 1, a circuit layer 11 disposed within the PCB board 1, a plating layer 12 and an insulating dielectric layer 13 covered on the circuit layer 11, and a corner structure 111 disposed on the circuit layer 11, with at least one corner structure 111.

[0024] In this embodiment, specifically, the corner structure 111 adopts a 45° angled corner structure, and the side length of the 45° angled corner is 1.5 times the line width of the line layer 11, which effectively reduces signal reflection at the corner and makes signal transmission smoother.

[0025] In this embodiment, specifically, the corner structure 111 adopts an arc corner structure with a radius of twice the line width of the line layer 11. Through a smooth transition, the signal is avoided from being reflected and distorted due to abrupt right angle changes, ensuring the integrity of the high-frequency signal at the corner structure 111, thereby improving the accuracy of the radar detection signal.

[0026] In this embodiment, specifically, the circuit layer 11 is a circuit layer that has undergone chemical polishing. The circuit layer 11 is polished using a mixed polishing liquid containing phosphoric acid, sulfuric acid and chromium anhydride at a temperature of 60°C for 15 minutes. The surface roughness Ra of the circuit layer 11 is ≤0.3μm. By reducing the surface roughness, the additional loss during signal transmission can be reduced, ensuring the efficient transmission of high-frequency signals.

[0027] In this embodiment, specifically, the plating layer 12 is a plating layer processed by pulse electroplating process, wherein the forward pulse current density is set to 8-10 A / dm². 2 The pulse width is 10-20 ms, and the reverse pulse current density is 2-3 A / dm. 2 The thickness of the plating layer 12 produced by pulse electroplating with a pulse interval of 30-50ms is more uniform. Through the periodic change of pulse current, metal ions in the electroplating solution are deposited more uniformly on the circuit surface under the action of electric field. Compared with the traditional electroplating process, the thickness uniformity error of plating layer 12 is within ±5%, which effectively improves the conductivity and oxidation resistance of the circuit and extends the service life of PCB.

[0028] In this embodiment, specifically, the insulating dielectric layer 13 is a silicon dioxide nanoscale insulating dielectric layer prepared by chemical vapor deposition (CVD) process. The insulating dielectric layer 13 has a thickness of 50nm. The insulating dielectric layer 13 can further reduce signal transmission loss, improve the insulation performance of the circuit, prevent short circuits between circuits and other problems, and ensure the stability of PCB operation.

[0029] Example 1:

[0030] PCB board 1 was polished for 15 minutes at 60°C using a mixed polishing solution containing phosphoric acid (40% by volume), sulfuric acid (30% by volume), and chromic anhydride (50 g / L by mass). The surface roughness Ra of the circuit layer 11 was measured to be 0.25 μm.

[0031] The polished PCB board 1 is placed in the CVD equipment chamber, and silane gas and oxygen are introduced. The reaction is carried out for 30 minutes at a temperature of 400℃ and a pressure of 100Pa. The thickness of the silicon dioxide insulating dielectric layer deposited on the surface of the circuit layer 11 is 50nm.

[0032] The corner structure 111 adopts a 45° bevel angle. The line width of the circuit layer 11 is 0.1mm, so the side length of the 45° bevel angle is set to 0.15mm. The 45° bevel angle of the circuit corner is processed by photolithography and etching processes.

[0033] A stirring device is installed in the electroplating tank, employing magnetic stirring at a speed controlled at 100-150 r / min. This device maintains a uniform flow of the electroplating solution, preventing inconsistent plating thickness caused by uneven solution concentration and further ensuring coating uniformity. The positive pulse current density is set to 9 A / dm³. 2 The pulse width is 15ms, and the reverse pulse current density is 2.5A / dm. 2 The pulse interval is 40ms. Copper sulfate electroplating solution is added to the electroplating tank. The PCB circuit board is immersed in the electroplating solution for 20 minutes. At the same time, the magnetic stirring device is turned on and the stirring speed is controlled at 120r / min. After the electroplating is completed, the thickness uniformity error of the plating layer 12 is within ±4%, and the plating thickness is 20μm.

[0034] The performance of the PCB circuit board prepared in Example 1 was tested: at a frequency of 77 GHz, the signal transmission loss was reduced by 25%; the signal reflection was tested using a network analyzer, and the signal reflection intensity was reduced by 42%; the oxidation resistance of the coating was evaluated by a salt spray test (test time 48 hours), and there was no obvious corrosion on the circuit surface. Compared with the circuit board prepared by traditional process, its service life is expected to be extended by 35%.

[0035] Any technical solution that achieves the above-mentioned technical effects by utilizing the technical solution described in this utility model, or by designing a similar technical solution inspired by the technical solution of this utility model, falls within the protection scope of this utility model.

Claims

1. An optimized PCB circuit structure for a 77GHz millimeter-wave radar for automobiles, characterized in that, The optimized PCB circuit structure for the 77GHz millimeter-wave radar for automobiles includes a PCB board (1), a circuit layer (11) is provided in the PCB board (1), a plating layer (12) and an insulating dielectric layer (13) are provided on the circuit layer (11), and the circuit layer (11) is provided with a corner structure (111), and at least one corner structure (111) is provided.

2. The PCB circuit process optimization structure for automotive 77GHz millimeter-wave radar as described in claim 1, characterized in that, The corner structure (111) adopts a 45° angled corner structure, and the side length of the 45° angled corner is 1.5 times the line width of the line layer (11).

3. The PCB circuit process optimization structure for automotive 77GHz millimeter-wave radar as described in claim 1, characterized in that, The corner structure (111) adopts an arc corner structure, and the radius of the arc is twice the line width of the line layer (11).

4. The PCB circuit process optimization structure for automotive 77GHz millimeter-wave radar as described in claim 1, characterized in that, The circuit layer (11) is a circuit layer that has undergone chemical polishing treatment, and the surface roughness Ra of the circuit layer (11) is ≤0.3μm.

5. The PCB circuit process optimization structure for automotive 77GHz millimeter-wave radar as described in claim 1, characterized in that, The coating (12) is processed by pulse electroplating process, and the thickness uniformity error of the coating (12) is ±5%.

6. The PCB circuit process optimization structure for automotive 77GHz millimeter-wave radar as described in claim 1, characterized in that, The insulating dielectric layer (13) is a silicon dioxide nanoscale insulating dielectric layer prepared by chemical vapor deposition (CVD) process, and the thickness of the insulating dielectric layer (13) is 50 nm.

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