Waveguide vertical interconnection conversion structure suitable for millimeter wave radar

Abstract

The utility model relates to the technical field of automobile radar antennas, and discloses a waveguide vertical interconnection conversion structure suitable for a millimeter wave radar, which comprises a vertical transmission channel and a horizontal transmission channel. The stepped transition structure is connected with the vertical transmission channel and the horizontal transmission channel; the PCB feed layer, the single-ridge waveguide cavity and one part of the stepped transition structure form a vertical transmission channel; the rectangular waveguide cavity and the other part of the stepped transition structure form a horizontal transmission channel; the surface of one end of the PCB feed layer is provided with double-ridge waveguide cavities which are used for being connected with waveguide ports of a packaging chip in a one-to-one correspondence mode. According to the utility model, the ridge width and the ridge height of the single-ridge waveguide are reasonably designed, so that efficient transmission of electromagnetic waves is realized, and the reflectivity is reduced; the stepped conversion structure can convert electromagnetic waves into the direction perpendicular to the original transmission direction, and the reflectivity of the electromagnetic waves is reduced by reasonably designing the size of the stepped conversion structure.

Description

Technical Field

[0001] This utility model relates to the field of automotive radar antenna technology, and in particular to a waveguide vertical interconnect conversion structure suitable for millimeter-wave radar. Background Technology

[0002] Automotive millimeter-wave radar is a sensor technology that utilizes millimeter-wave frequencies (typically 24 GHz, 77 GHz, and 79 GHz) for detection. It acquires information such as the distance, speed, and orientation of targets by emitting electromagnetic waves and receiving the echoes reflected from them, providing vehicles with environmental perception capabilities. It is one of the key technologies for realizing Advanced Driver Assistance Systems (ADAS) and autonomous driving.

[0003] Compared to lidar, millimeter-wave radar offers advantages such as all-weather operation, long detection range, and compact size. Millimeter waves are less affected by weather conditions, allowing them to operate normally in adverse weather conditions such as rain, snow, and fog, providing stable environmental perception. 77GHz radar can detect distances exceeding 200 meters, enabling early detection of distant targets and providing vehicles with longer reaction time. The small antenna size of millimeter-wave radar makes it easy to integrate into vehicles without affecting their exterior design. On highways, millimeter-wave radar can monitor the distance and speed of vehicles ahead in real time, enabling adaptive cruise control (ACC) and reducing driver fatigue. When a potential collision risk is detected, the automatic emergency braking system (AEB) intervenes promptly to effectively avoid or mitigate accident damage. In urban environments, millimeter-wave radar can accurately identify pedestrians, bicycles, and other targets, providing reliable data support for automatic emergency braking and blind spot detection (BSD), improving driving safety in urban areas. Furthermore, millimeter-wave radar can also be applied to functions such as automatic parking and traffic jam assist, bringing users a more convenient and comfortable driving experience. With the continuous development of autonomous driving technology, millimeter-wave radar will be deeply integrated with other sensors to provide strong perception support for achieving higher levels of autonomous driving.

[0004] 77 GHz automotive millimeter-wave radar is undergoing a transition from microstrip antennas to waveguide antennas. Waveguide structures offer low transmission loss, enabling higher antenna gain and radiation efficiency, supporting wider signal bandwidth, and improving radar detection range and resolution. Furthermore, waveguide antennas, constructed of metal, can withstand greater mechanical stress and environmental pressure, and their excellent heat dissipation allows them to handle higher power. In systems requiring high-power signal transmission, such as radar and satellite communications, waveguide antennas prevent performance degradation or damage due to excessive power, adapt to various harsh environmental conditions, and ensure long-term reliable radar operation.

[0005] The detection performance of millimeter-wave imaging radar is closely related to the antenna layout. However, since imaging radar usually adopts a multi-antenna transceiver architecture, the design of the wiring layout between the compactly distributed chip ports and each waveguide antenna has become a key technical challenge.

[0006] Traditional millimeter-wave interconnect methods typically involve first transforming a planar transmission structure, easily integrated with the chip, from the horizontal plane of the substrate to a direction perpendicular to the substrate's horizontal plane, forming a millimeter-wave interface. Then, the two vertical interfaces are connected to each other via probes or metal vias, achieving vertical interconnection between the two substrates, such as the common "microstrip-probe-waveguide" type of vertical interconnection. However, this interconnection structure includes more than one type of circuit element and requires mixed-voltage integration technology, increasing the complexity and difficulty of the process, hindering high-density integration, and causing problems such as high matching difficulty and high losses. In recent years, with the advancement of process technology, chips directly fed by waveguide ports have achieved mass production. However, this feeding method requires achieving vertical interconnection conversion of signals within a limited area, thus necessitating the design of a conversion structure with high bandwidth, low reflection, and easy fabrication for the chip's waveguide ports. Utility Model Content

[0007] This invention addresses the problem of signal transmission between chips and waveguide antennas on the same board, proposing a waveguide vertical interconnect conversion structure suitable for millimeter-wave radar, comprising:

[0008] Vertical transmission channel, horizontal transmission channel, stepped transition structure (4), PCB feed layer (2), single ridge waveguide cavity (3), rectangular waveguide cavity (1);

[0009] The stepped transition structure (4) connects the vertical transmission channel and the horizontal transmission channel; a portion of the PCB feed layer (2), the single-ridge waveguide cavity (3), and the stepped transition structure (4) constitutes the vertical transmission channel; another portion of the rectangular waveguide cavity (1) and the stepped transition structure (4) constitutes the horizontal transmission channel; a double-ridge waveguide cavity (5) is provided on the surface of one end of the PCB feed layer (2) for corresponding connection with the waveguide port of the packaged chip.

[0010] As a preferred technical solution, the stepped transition structure (4) is formed by extending the ridge (6) of the single ridge waveguide cavity (3), including a first ridge 41 and a second ridge 42. The height of the first ridge is consistent with the height of the ridge (6) of the single ridge waveguide cavity (3), and the upper surface of the second ridge (42) is bent at 90° to form a stepped transition section.

[0011] As a preferred technical solution, the length of the bent portion of the stepped transition structure (4) is 1 / 10 to 1 / 5 of the wavelength of the transmitted electromagnetic waveguide.

[0012] As a preferred technical solution, the single-ridge waveguide cavity (3) is vertically connected to the surface of the other end of the PCB feed layer (2).

[0013] As a preferred technical solution, the ridge height of the single-ridge waveguide cavity (3) is 1 / 15 to 1 / 5 of the wavelength of the transmitted electromagnetic wave, which is slightly higher than the ridge height of the double-ridge waveguide cavity (5); the ridge width of the single-ridge waveguide cavity (3) is 1 / 5 to 1 / 4 of the wavelength of the transmitted electromagnetic wave; the length and width of the single-ridge waveguide cavity (3) are consistent with those of the double-ridge waveguide cavity.

[0014] As a preferred technical solution, the double-ridge waveguide cavity (5) is formed by metallization through-hole process, and its size matches the chip waveguide port.

[0015] This utility model has the following beneficial effects:

[0016] The vertical interconnection conversion structure proposed in this invention uses a single-ridge waveguide and a stepped transition structure to convert electromagnetic waves from a double-ridge waveguide port to a rectangular waveguide. The single-ridge waveguide is connected to the chip waveguide port, completing the transmission of electromagnetic waves from the double-ridge waveguide to the single-ridge waveguide. By rationally designing the ridge width and ridge height of the single-ridge waveguide, efficient transmission of electromagnetic waves is achieved, reducing reflectivity. The ridge edge of the single-ridge waveguide is located on the sidewall of one of the wide sides of the single-ridge waveguide, and this sidewall is on the same plane as the cross-section of one end of the rectangular waveguide. The stepped conversion structure can convert electromagnetic waves into a vertical direction from the original transmission direction. By rationally designing the dimensions of the stepped conversion structure, the reflectivity of electromagnetic waves is reduced. Attached Figure Description

[0017] Figure 1 This is a three-dimensional view of a waveguide conversion structure proposed in one embodiment of this application;

[0018] Figure 2 This is a 3D view of the PCB power supply layer;

[0019] Figure 3 This is a top view of a double-ridged waveguide cavity;

[0020] Figure 4 This is a three-dimensional view of a single-ridge waveguide proposed in one embodiment of this application;

[0021] Figure 5 This is a three-dimensional view of a rectangular waveguide and stepped transition structure proposed in one embodiment of this application;

[0022] Figure 6 This is a side view of a rectangular waveguide and stepped transition structure proposed in one embodiment of this application;

[0023] Figure 7 This is a perspective view of a stepped transition structure proposed in one embodiment of this application;

[0024] Figure 8 This is a transmission coefficient and reflection coefficient curve of a vertical interconnect conversion structure proposed in one embodiment of this application. Detailed Implementation

[0025] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" or "having" and any variations thereof are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] In the description of this utility model, it should be understood that the terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this utility model, and are not intended to indicate or imply that the elements referred to must have a specific orientation, be constructed or operated in a specific orientation, and therefore should not be construed as limiting this utility model.

[0027] This utility model discloses a waveguide vertical interconnection conversion structure suitable for millimeter-wave radar, comprising a vertical transmission channel, a horizontal transmission channel, a stepped transition structure (4), a PCB feed layer (2), a single-ridge waveguide cavity (3), and a rectangular waveguide cavity (1); the stepped transition structure (4) connects the vertical transmission channel and the horizontal transmission channel; a portion of the PCB feed layer (2), the single-ridge waveguide cavity (3), and the stepped transition structure (4) constitutes the vertical transmission channel; the other portion of the rectangular waveguide cavity (1) and the stepped transition structure (4) constitutes the horizontal transmission channel; a double-ridge waveguide cavity (5) is provided on the surface of one end of the PCB feed layer (2) for corresponding connection with the waveguide port of the packaged chip.

[0028] Specifically, such as Figure 1 This is a schematic diagram of a vertical interconnection transition structure between a waveguide-packaged chip and a waveguide antenna provided in an embodiment of this utility model. It shows a rectangular waveguide (1), a PCB feed layer (2), a single-ridge waveguide cavity (3), a stepped transition structure (4), and a double-ridge waveguide cavity (5). In this embodiment, the waveguide transition structure is divided into a vertical transmission channel and a horizontal transmission channel. The PCB feed layer, a portion of the single-ridge waveguide, and a part of the stepped transition structure constitute the vertical transmission channel, in which electromagnetic waves propagate through layers in a direction perpendicular to the PCB surface. A portion of the rectangular waveguide and the stepped transition structure constitute the horizontal transmission channel, which is ultimately connected to a horizontally placed waveguide antenna. In this channel, electromagnetic waves propagate in a direction parallel to the PCB surface.

[0029] like Figure 2 This is a PCB feed layer according to an embodiment of the present invention, showing the distribution of eight double-ridge waveguide cavities. A packaged chip is disposed on the first surface of the PCB feed layer, and the waveguide ports of the chip are connected one-to-one with the double-ridge waveguide cavities of the PCB feed layer. A vertical interconnect conversion structure is disposed on the second surface of the PCB feed layer. The PCB feed layer can be made of FR-4 (epoxy fiberglass board) or other materials, with a thickness of 0.254 mm. Copper is deposited on both the first and second surfaces of the PCB feed layer, with a copper thickness of 0.035 mm. The eight double-ridge waveguide cavities are constructed using a metallized through-hole process; depending on different process standards, the average metal wall thickness can be between 10 micrometers and 25 micrometers.

[0030] like Figure 3 This is a top view of the double-ridged waveguide cavity, used to transmit and receive electromagnetic signals from the packaged chip. Its dimensions are consistent with the waveguide port of the Texas Instruments AWR2544 chip, ensuring good impedance matching between the chip and the PCB. The frequency of the electromagnetic signals transmitted and received at the transceiver terminals of the packaged chip is 74~81 GHz.

[0031] like Figure 4 This is a three-dimensional view of a single-ridge waveguide. In this embodiment, the electromagnetic signal in the double-ridge waveguide cavity can be transmitted to the single-ridge waveguide, or the electromagnetic signal in the single-ridge waveguide can be transmitted to the double-ridge waveguide cavity, thus completing the transition between the double-ridge waveguide and the single-ridge waveguide. Since the double-ridge waveguide directly connecting to the rectangular waveguide will cause severe impedance and mode mismatch, a single-ridge waveguide cavity (3) is required to achieve the transition between the two. The ridge height (6) of the single-ridge waveguide is about 1 / 10 of the wavelength of the transmitted electromagnetic wave, which is slightly higher than the ridge height of the double-ridge waveguide. The ridge width w is about 1 / 5 to 1 / 4 of the wavelength of the transmitted electromagnetic wave. Specifically, w is set to 1.05 mm. The length and width of the single-ridge waveguide cavity are consistent with those of the double-ridge waveguide cavity, so that there will be no trace interference between the signal channels in the chip, which is beneficial for wiring.

[0032] like Figure 5 This is a three-dimensional view of the rectangular waveguide and stepped transition structure proposed in this embodiment of the present invention. A stepped transition structure (4) is provided on the side wall of one end of the rectangular waveguide (1). The rectangular waveguide (1) is connected to the single-ridge waveguide cavity (3) to form a through cavity. After docking, the electromagnetic wave transmission direction of the rectangular wave is perpendicular to the electromagnetic wave transmission direction of the single-ridge waveguide.

[0033] Specifically, rectangular waveguides (1) and single-ridge waveguide cavities (3) are generally important waveguide devices that use metal tubes to transmit electromagnetic waves. Their tube walls are usually made of copper, aluminum or other metal materials with good conductivity. They are characterized by simple structure, high mechanical strength, high power capacity and low transmission loss.

[0034] like Figure 6 , is a side view of the rectangular waveguide and the stepped transition conversion structure. The stepped transition conversion structure (4) can be regarded as the ridge of the single ridge waveguide extending to the upper surface 11 of the rectangular waveguide and producing a 90° bend. The length of the bend (the height of the second ridge 42 of the stepped transition structure) h2 is 1 / 10 to 1 / 5 of the wavelength of the transmitted electromagnetic wave. This length significantly affects the impedance matching of the conversion structure. Specifically, h2 is set to 1.13 mm. This value is the result of optimization and is not limited in this application. The height of the first ridge 41 h1 is 0.49 mm, which is consistent with the ridge height of the single ridge waveguide.

[0035] When the emitter port of the packaged chip emits electromagnetic waves, the electromagnetic signal passes through the double-ridged waveguide cavity and single-ridged waveguide of the PCB feed layer, such as... Figure 7 Furthermore, through the first ridge 41 and the second ridge 42 of the stepped transition conversion structure (4), the electromagnetic signal transition from the vertical transmission direction of the packaged chip to the horizontal transmission direction of the rectangular waveguide is realized. Further, the interlayer vertical interconnection conversion structure in this embodiment can also realize the transition from the horizontal transmission direction of the rectangular waveguide to the vertical transmission direction of the packaged chip. This structure is relatively simple and easy to process using injection molding or CNC technology.

[0036] It should be noted that the electromagnetic wave transmission direction in this embodiment is not a fixed direction. The transmission direction of the electromagnetic wave is described based on the spatial relationship between the chip and the rectangular waveguide, and their vertical placement. This embodiment does not impose specific restrictions on the conversion of the electromagnetic wave transmission direction.

[0037] like Figure 8 The figure shows the transmission and reflection coefficient curves of an interlayer vertical interconnect conversion structure proposed in one embodiment of this application. For electromagnetic signals in the frequency range of 75~80 GHz, the interlayer transition structure has low transmission loss, less than 0.1 dB.

[0038] As can be seen, the vertical interconnection conversion structure proposed in this utility model uses a single-ridge waveguide and a stepped transition structure to realize the conversion of electromagnetic waves from a double-ridge waveguide port to a rectangular waveguide. The single-ridge waveguide is connected to the chip waveguide port to complete the transmission of electromagnetic waves from the double-ridge waveguide to the single-ridge waveguide. By rationally designing the ridge width and ridge height of the single-ridge waveguide, efficient transmission of electromagnetic waves is achieved and the reflectivity is reduced. The ridge edge of the single-ridge waveguide is located on the side wall of one of the wide sides of the single-ridge waveguide, and this side wall is on the same plane as the cross-section of one end of the rectangular waveguide. The stepped conversion structure can convert electromagnetic waves into the vertical direction of the original transmission direction. By rationally designing the dimensions of the stepped conversion structure, the reflectivity of electromagnetic waves is reduced.

[0039] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A waveguide vertical interconnect conversion structure suitable for millimeter-wave radar, characterized in that, include: Vertical transmission channel, horizontal transmission channel, stepped transition structure (4), PCB feed layer (2), single ridge waveguide cavity (3), rectangular waveguide cavity (1); The stepped transition structure (4) connects the vertical transmission channel and the horizontal transmission channel; The PCB feed layer (2), the single-ridge waveguide cavity (3), and a portion of the stepped transition structure (4) constitute a vertical transmission channel; The other part of the rectangular waveguide cavity (1) and the stepped transition structure (4) constitutes a horizontal transmission channel; A double-ridge waveguide cavity (5) is provided on one end of the PCB feed layer (2) for connection with the waveguide port of the packaged chip.

2. The waveguide vertical interconnection conversion structure suitable for millimeter-wave radar according to claim 1, characterized in that, The stepped transition structure (4) is formed by extending the ridge (6) of the single-ridge waveguide cavity (3), including a first ridge (41) and a second ridge (42). The height of the first ridge is consistent with the height of the ridge (6) of the single-ridge waveguide cavity (3), and the upper surface of the second ridge (42) is bent at 90° to form a stepped transition section.

3. A waveguide vertical interconnection conversion structure suitable for millimeter-wave radar according to claim 2, characterized in that, The length of the bent portion of the stepped transition structure (4) is 1 / 10 to 1 / 5 of the wavelength of the transmitted electromagnetic waveguide.

4. A waveguide vertical interconnection conversion structure suitable for millimeter-wave radar according to claim 1, characterized in that, The single-ridge waveguide cavity (3) is vertically connected to the surface of the other end of the PCB feed layer (2).

5. A waveguide vertical interconnection conversion structure suitable for millimeter-wave radar according to claim 4, characterized in that, The ridge height of the single-ridge waveguide cavity (3) is 1 / 15 to 1 / 5 of the wavelength of the transmitted electromagnetic wave, which is slightly higher than the ridge height of the double-ridge waveguide cavity (5); the ridge width of the single-ridge waveguide cavity (3) is 1 / 5 to 1 / 4 of the wavelength of the transmitted electromagnetic wave; the length and width of the single-ridge waveguide cavity (3) are consistent with those of the double-ridge waveguide cavity.

6. A waveguide vertical interconnection conversion structure suitable for millimeter-wave radar according to claim 1, characterized in that, The double-ridged waveguide cavity (5) is formed by metallization via process and its size matches the chip waveguide port.

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