Dielectric gap waveguide millimeter wave radar antenna
By using a multi-layer PCB design with a dielectric gap waveguide structure, the problems of assembly accuracy and electromagnetic wave leakage in vehicle-mounted millimeter-wave radar antennas were solved, achieving low-cost, high-efficiency signal transmission and detection performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- WEIFU INTELLIGENT SENSE (WUXI) TECH CO LTD
- Filing Date
- 2025-08-08
- Publication Date
- 2026-06-12
Smart Images
Figure CN224355442U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of vehicle-mounted radar technology, and in particular to a dielectric gap waveguide millimeter-wave radar antenna. Background Technology
[0002] In the field of automotive millimeter-wave radar technology, the key to improving detection performance lies in reducing signal transmission loss. To this end, chip manufacturers have developed chips adapted to waveguide structures. By designing the chip interface as a waveguide port, users only need to create corresponding waveguide slots on the PCB board to achieve radar signal transmission. However, this design places stringent requirements on the matching antenna solution, and existing technologies have revealed significant shortcomings in practical applications.
[0003] In traditional solutions, although waveguide antennas offer the advantage of low transmission loss, their extremely high assembly precision requirements and large size become significant bottlenecks. Even minor deviations during assembly can cause electromagnetic wave leakage, directly leading to a surge in insertion loss and severely weakening antenna gain. To mitigate the impact of assembly errors, gapped waveguide antennas are widely used. These antennas constrain electromagnetic waves through periodic metal pillars on both sides of the transmission channel, and the air cavity height reserved between the metal pillars and the top metal plane reduces the sensitivity to assembly deviations, achieving performance comparable to traditional waveguide antennas. However, the extreme precision requirements of this solution result in high manufacturing costs, making it difficult to meet the economic requirements of large-scale mass production of automotive radar. Summary of the Invention
[0004] The purpose of this invention is to provide a dielectric gap waveguide millimeter-wave radar antenna to solve the problems existing in the prior art.
[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:
[0006] A dielectric-gap waveguide millimeter-wave radar antenna, comprising:
[0007] Waveguide antenna layer, which has slotted radiation ports;
[0008] The first PCB layer, located below the waveguide antenna layer, is provided with an antenna radiation cavity and a first grounding hole periodically arranged around the outer periphery of the antenna radiation cavity.
[0009] The second PCB layer, located below the first PCB layer, has a waveguide transmission channel and second grounding holes periodically arranged around the outer periphery of the waveguide transmission channel; and
[0010] The third PCB layer, located below the second PCB layer, has a chip waveguide port.
[0011] A first metal pad is provided between the waveguide antenna layer and the first PCB layer, and a second metal pad is provided between the first PCB layer and the second PCB layer.
[0012] In one possible implementation, a first ground layer and a second ground layer are respectively provided on both sides of the third PCB layer, a third ground layer is provided on the side of the second PCB layer close to the third PCB layer, and a fourth ground layer is provided on the side of the first PCB layer away from the waveguide antenna layer.
[0013] In one possible implementation, the first grounding hole is embedded with a first copper pillar connected to the fourth grounding layer, and the second grounding hole is embedded with a second copper pillar connected to the third grounding layer.
[0014] In one possible implementation, both the first metal pad and the second metal pad are frame structures to form air cavities between the waveguide antenna layer and the first PCB layer, and between the fourth ground layer and the second PCB layer.
[0015] In one possible implementation, the thickness of both the first metal pad and the second metal pad is 0.1 mm.
[0016] In one possible implementation, two choke slots are provided on the side of the waveguide antenna layer away from the first metal pad layer, and the two choke slots are respectively located on both sides of the slot radiation port.
[0017] In one possible implementation, the first PCB layer, the second PCB layer, and the third PCB layer are all FR-4 PCBs, wherein the FR-4 PCB has a dielectric constant of 4.4, a loss tangent of 0.02, and a thickness of 0.5 mm.
[0018] In one possible implementation, the first grounding hole has a diameter of 0.2 mm, a pad diameter of 0.38 mm, a height of 0.5 mm, and a spacing of 0.5 mm between two adjacent grounding holes; the second grounding hole has a diameter of 0.2 mm, a pad diameter of 0.38 mm, a height of 0.5 mm, and a spacing of 0.5 mm between two adjacent grounding holes.
[0019] In one possible implementation, the inner wall of the chip waveguide port is provided with a metal plating layer to form a metallized structure.
[0020] The beneficial effects of the technical solution provided by this utility model include at least the following:
[0021] This technical solution includes a waveguide antenna layer with a slotted radiation port; a first PCB layer located below the waveguide antenna layer, which includes an antenna radiation cavity and first grounding holes periodically arranged around the periphery of the antenna radiation cavity; a second PCB layer located below the first PCB layer, which includes a waveguide transmission channel and second grounding holes periodically arranged around the periphery of the waveguide transmission channel; and a third PCB layer located below the second PCB layer, which includes a chip waveguide port; wherein a first metal pad layer is provided between the waveguide antenna layer and the first PCB layer, and a second metal pad layer is provided between the first PCB layer and the second PCB layer. In this case, compared with a slotted waveguide antenna, the waveguide transmission channel and antenna radiation cavity constructed using PCBs can significantly reduce production costs. The precision of the grounding holes processed on the PCB is much greater than that of metal pillars, and compared with the total thickness of the slotted waveguide antenna, the total thickness of the antenna structure in this solution can be significantly reduced. Attached Figure Description
[0022] The accompanying drawings are provided to further understand the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation thereof.
[0023] Figure 1 An exploded view of a dielectric gap waveguide millimeter-wave radar antenna provided in an exemplary embodiment of the present invention is shown.
[0024] Figure 2 This diagram illustrates the structure of the first PCB layer of a dielectric gap waveguide millimeter-wave radar antenna provided in an exemplary embodiment of the present invention.
[0025] Figure 3 This diagram illustrates the structure of the second PCB layer of a dielectric gap waveguide millimeter-wave radar antenna provided in an exemplary embodiment of the present invention.
[0026] Figure 4 This diagram illustrates the structure of the chip waveguide port of a dielectric gap waveguide millimeter-wave radar antenna provided in an exemplary embodiment of the present invention.
[0027] Figure 5 The diagram shows the S-parameters of a dielectric gap waveguide millimeter-wave radar antenna provided in an exemplary embodiment of the present invention.
[0028] Figure 6 The diagram shows the radiation pattern of a dielectric gap waveguide millimeter-wave radar antenna provided in an exemplary embodiment of the present invention.
[0029] In the picture:
[0030] 1. Waveguide antenna layer; 101. Slot radiation port; 2. First PCB layer; 201. Antenna radiation cavity; 202. First grounding hole; 203. First copper pillar; 3. Second PCB layer; 301. Waveguide transmission channel; 302. Second grounding hole; 303. Second copper pillar; 4. Third PCB layer; 401. Chip waveguide port; 5. First metal pad layer; 6. Second metal pad layer; 7. First grounding layer; 8. Second grounding layer; 9. Third grounding layer; 10. Fourth grounding layer; 11. Choke slot. Detailed Implementation
[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0032] In this specification, identical components are represented by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "upper," and "lower" used in the following description refer to directions in the accompanying drawings of this utility model, while the terms "bottom surface," "top surface," "inner," and "outer" refer to directions towards or away from a specific component, respectively. 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 indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "multiple" means two or more.
[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0034] Please see Figures 1 to 4 The dielectric gap waveguide millimeter-wave radar antenna includes: a waveguide antenna layer 1, which has a slotted radiation port 101; a first PCB layer 2, which is located below the waveguide antenna layer 1, which has an antenna radiation cavity 201 and a first grounding hole 202 periodically arranged around the outer periphery of the antenna radiation cavity 201; a second PCB layer 3, which is located below the first PCB layer 2, which has a waveguide transmission channel 301 and a second grounding hole 302 periodically arranged around the outer periphery of the waveguide transmission channel 301; and a third PCB layer 4, which is located below the second PCB layer 3, which has a chip waveguide port 401; wherein, a first metal pad layer 5 is provided between the waveguide antenna layer 1 and the first PCB layer 2, and a second metal pad layer 6 is provided between the first PCB layer 2 and the second PCB layer 3.
[0035] In this embodiment, the chip waveguide port on the third PCB layer of the dielectric gap waveguide millimeter-wave radar antenna serves as the electromagnetic wave entrance, connecting to the radar chip and introducing electromagnetic waves to initiate the signal transmission link. After entering, the electromagnetic wave completes its main path transmission through the waveguide transmission channel on the second PCB layer. The second grounding hole on its outer periphery forms an equivalent metal wall, constraining the directional propagation of the electromagnetic wave. Subsequently, the electromagnetic wave enters the antenna radiation cavity on the first PCB layer, which provides a buffer space before radiation. The first grounding hole on its outer periphery forms electromagnetic shielding, suppressing leakage and enhancing signal directivity. Finally, the electromagnetic wave radiates outward through the gap radiation port on the waveguide antenna layer, the size and arrangement of which determine the radiation direction and gain.
[0036] Further, see Figures 1 to 3 The third PCB layer 4 has a first ground layer 7 and a second ground layer 8 on its two sides, respectively. The second PCB layer 3 has a third ground layer 9 on its side closest to the third PCB layer 4, and the first PCB layer 2 has a fourth ground layer 10 on its side furthest from the waveguide antenna layer 1. A first copper pillar 203 connected to the fourth ground layer 10 is embedded in the first ground hole 202, and a second copper pillar 303 connected to the third ground layer 9 is embedded in the second ground hole 302.
[0037] In this embodiment, the first and second ground layers on both sides of the third PCB layer, together with the third ground layer on the side of the second PCB layer closer to the third PCB layer and the fourth ground layer on the side of the first PCB layer farther from the waveguide antenna layer, form a multi-layer three-dimensional shielding network. The first copper pillar within the first grounding hole connects to the fourth ground layer, connecting the shielding structure around the first PCB layer to the ground layer; the second copper pillar within the second grounding hole connects to the third ground layer, strengthening the grounding shielding of the transmission channel of the second PCB layer. In this case, connecting the periodic grounding holes to the corresponding ground layers via copper pillars constructs a continuous low-impedance grounding path, further suppressing electromagnetic leakage and external interference, and improving the stability of signal transmission across each layer.
[0038] Furthermore, see Figure 1 Both the first metal pad 5 and the second metal pad 6 are frame structures, forming air cavities between the waveguide antenna layer 1 and the first PCB layer 2, and between the fourth ground layer 10 and the second PCB layer 3. The thickness of both the first metal pad 5 and the second metal pad 6 is 0.1 mm.
[0039] In this embodiment, the first and second metal pads adopt a frame structure, which can enclose an air cavity between the waveguide antenna layer and the first PCB layer, and between the fourth ground layer and the second PCB layer. The 0.1mm thickness precisely controls the height of the air cavity, which can reduce assembly errors and improve signal transmission efficiency.
[0040] For details, please refer to Figure 1 Two choke slots 11 are provided on the side of the waveguide antenna layer 1 away from the first metal pad layer 5. The two choke slots 11 are located on both sides of the slot radiation port 101.
[0041] In this embodiment, two choke slots are provided on both sides of the slot radiation port on the side of the waveguide antenna layer away from the first metal pad layer. This effectively suppresses creeping waves along the antenna surface. Creeping waves cause unnecessary signal energy loss and interfere with the radiation pattern, resulting in a decrease in main lobe gain and an increase in side lobes. The choke slots, by changing the electromagnetic wave propagation path, utilize electromagnetic resonance within the slots to cancel out creeping wave energy, thereby enhancing the directional radiation capability of the slot radiation port.
[0042] More specifically, the first PCB layer 2, the second PCB layer 3, and the third PCB layer 4 are all FR-4 PCBs. The dielectric constant of the FR-4 PCB is 4.4, the loss tangent is 0.02, and the thickness is 0.5mm.
[0043] In this embodiment, the first, second, and third PCB layers use FR-4 substrate with a dielectric constant of 4.4 and a thickness of 0.5 mm. Combined with the periodically arranged grounding vias around the transmission channel and antenna radiating cavity, this creates a transmission environment suitable for millimeter-wave signals, preventing signal refraction or dispersion due to substrate parameter fluctuations. A loss tangent of 0.02° represents a low-loss level, reducing energy attenuation of electromagnetic waves during interlayer transmission and ensuring signal strength. The low cost of FR-4, combined with its aforementioned electrical properties, satisfies the radar's signal integrity requirements while reducing assembly errors in the multilayer structure through standardized substrate specifications.
[0044] Specifically, the first grounding hole 202 has a diameter of 0.2mm, a pad diameter of 0.38mm, a height of 0.5mm, and a spacing of 0.5mm between two adjacent grounding holes; the second grounding hole 302 has a diameter of 0.2mm, a pad diameter of 0.38mm, a height of 0.5mm, and a spacing of 0.5mm between two adjacent grounding holes.
[0045] In this embodiment, the 0.5mm grounding hole height is consistent with the PCB layer thickness, ensuring that the grounding hole penetrates the entire substrate and achieves effective conduction of the interlayer grounding structure; the 0.5mm adjacent spacing makes the grounding holes form a dense periodic array, which is equivalent to a continuous metal barrier, enhancing the ability to confine electromagnetic waves and suppressing leakage and interference.
[0046] More specifically, see Figure 4 The inner wall of the chip waveguide port 401 is provided with a metal plating layer to form a metallized structure.
[0047] In this embodiment, the metal plating on the inner wall of the chip waveguide port forms a metallized structure, which is crucial for efficient electromagnetic wave coupling. The excellent conductivity of the metal material confines the electromagnetic waves output by the chip within the waveguide port, preventing signal leakage to the sidewall substrate and reducing transmission loss. Simultaneously, the metallized structure creates a continuous conductive interface on the inner wall of the waveguide port, ensuring stable transmission of electromagnetic waves along a predetermined path to the waveguide transmission channel and reducing signal reflection caused by interface discontinuities.
[0048] Effect verification:
[0049] Figure 5 The diagram shows the S-parameters of a dielectric-gap waveguide millimeter-wave radar antenna provided in an exemplary embodiment of this invention. The S-parameters indicate that the operating frequency band of the dielectric-gap waveguide millimeter-wave radar antenna provided by this technical solution is 75.3–79.8 GHz @ -15 dB, with a bandwidth of 4.5 GHz. This demonstrates that it can operate stably in the high-frequency millimeter-wave band, and its wide bandwidth can cover more detection scenarios, meeting the standard requirements for frequency bands for vehicle-mounted radar.
[0050] Figure 6 The diagram shows the radiation pattern of a dielectric-gap waveguide millimeter-wave radar antenna provided in an exemplary embodiment of this invention. The radiation pattern indicates that the gain of the dielectric-gap waveguide millimeter-wave radar antenna provided by this technical solution is approximately 14 dBi. This demonstrates that the antenna can effectively concentrate electromagnetic wave energy, improve signal radiation intensity and receiving sensitivity, and ensure long-range detection accuracy.
[0051] In summary, this technical solution includes a waveguide antenna layer with a slotted radiation port; a first PCB layer located below the waveguide antenna layer, which includes an antenna radiation cavity and a first grounding hole periodically arranged around the periphery of the antenna radiation cavity; a second PCB layer located below the first PCB layer, which includes a waveguide transmission channel and a second grounding hole periodically arranged around the periphery of the waveguide transmission channel; and a third PCB layer located below the second PCB layer, which includes a chip waveguide port. A first metal pad is provided between the waveguide antenna layer and the first PCB layer, and a second metal pad is provided between the first PCB layer and the second PCB layer. In this configuration, compared to a slotted waveguide antenna, the waveguide transmission channel and antenna radiation cavity constructed using PCBs can significantly reduce production costs. The precision of the grounding holes processed on the PCB is much greater than that of metal pillars, and the total thickness of the antenna structure in this solution can be significantly reduced compared to the total thickness of a slotted waveguide antenna.
[0052] In the embodiments disclosed in this utility model, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "linking" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments disclosed in this utility model according to the specific circumstances.
[0053] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.
Claims
1. A dielectric-gap waveguide millimeter-wave radar antenna, characterized in that, include: Waveguide antenna layer (1) is provided with a slot radiation port (101); The first PCB layer (2) is located below the waveguide antenna layer (1) and is provided with an antenna radiation cavity (201) and a first grounding hole (202) periodically arranged on the outer periphery of the antenna radiation cavity (201). The second PCB layer (3), located below the first PCB layer (2), is provided with a waveguide transmission channel (301) and second grounding holes (302) periodically arranged around the outer periphery of the waveguide transmission channel (301); and The third PCB layer (4) is located below the second PCB layer (3) and has a chip waveguide port (401). Among them, a first metal pad layer (5) is provided between the waveguide antenna layer (1) and the first PCB layer (2), and a second metal pad layer (6) is provided between the first PCB layer (2) and the second PCB layer (3).
2. The dielectric gap waveguide millimeter-wave radar antenna according to claim 1, characterized in that, The third PCB layer (4) has a first ground layer (7) and a second ground layer (8) on its two sides respectively. The second PCB layer (3) has a third ground layer (9) on its side close to the third PCB layer (4). The first PCB layer (2) has a fourth ground layer (10) on its side away from the waveguide antenna layer (1).
3. The dielectric gap waveguide millimeter-wave radar antenna according to claim 2, characterized in that, The first grounding hole (202) is embedded with a first copper pillar (203) connected to the fourth grounding layer (10), and the second grounding hole (302) is embedded with a second copper pillar (303) connected to the third grounding layer (9).
4. The dielectric gap waveguide millimeter-wave radar antenna according to claim 2, characterized in that, Both the first metal pad (5) and the second metal pad (6) are frame structures to form air cavities between the waveguide antenna layer (1) and the first PCB layer (2) and between the fourth ground layer (10) and the second PCB layer (3).
5. The dielectric gap waveguide millimeter-wave radar antenna according to claim 4, characterized in that, The thickness of the first metal pad (5) and the second metal pad (6) is 0.1 mm.
6. The dielectric gap waveguide millimeter-wave radar antenna according to claim 1, characterized in that, Two choke slots (11) are provided on the side of the waveguide antenna layer (1) away from the first metal pad layer (5), and the two choke slots (11) are located on both sides of the slot radiation port (101).
7. The dielectric gap waveguide millimeter-wave radar antenna according to claim 1, characterized in that, The first PCB layer (2), the second PCB layer (3), and the third PCB layer (4) are all FR-4 PCBs. The dielectric constant of the FR-4 PCB is 4.4, the loss tangent is 0.02, and the thickness is 0.5 mm.
8. The dielectric gap waveguide millimeter-wave radar antenna according to claim 1, characterized in that, The first grounding hole (202) has a diameter of 0.2 mm, a pad diameter of 0.38 mm, a height of 0.5 mm, and a spacing of 0.5 mm between two adjacent grounding holes; the second grounding hole (302) has a diameter of 0.2 mm, a pad diameter of 0.38 mm, a height of 0.5 mm, and a spacing of 0.5 mm between two adjacent grounding holes.
9. The dielectric gap waveguide millimeter-wave radar antenna according to claim 1, characterized in that, The inner wall of the chip waveguide port (401) is provided with a metal plating layer to form a metallized structure.