On-chip antenna structure of a millimeter wave radar chip and adjustment method thereof

Abstract

The application provides an on-chip antenna structure of a millimeter wave radar chip and a method for adjusting the same, and belongs to the technical field of on-chip antennas. The on-chip antenna structure comprises an internal air pressure cavity, a metal cavity pipeline, low-melting-point metal and a first lead wire. The internal air pressure cavity and the metal cavity pipeline are in communication at one end of the metal cavity pipeline, the metal cavity pipeline is horizontally arranged, the other end of the metal cavity pipeline forms an external air pressure adjusting outlet, the low-melting-point metal is arranged in the internal air pressure cavity and the metal cavity pipeline, and forms a metal antenna. The low-melting-point metal is connected with the first lead wire, and further connected with a radio frequency unit of the millimeter wave radar chip. According to the application, the shape of the on-chip antenna can be adjusted during the chip preparation process, the individualized radio frequency parameters are met, the chip flow is not required for multiple times, the cost of chip customization is greatly reduced, and the efficiency and effect of millimeter wave radar on-chip antenna customization are improved.

Description

Technical Field

[0001] This invention belongs to the field of on-chip antenna technology, specifically relating to an on-chip antenna structure for a millimeter-wave radar chip and its adjustment method. Background Technology

[0002] With the development of new energy vehicles, millimeter-wave radar technology has been widely applied. Millimeter-wave radar chips are mainly used in scenarios such as front radar and corner radar for external vehicle perception, as well as in-cabin occupant status monitoring. Meanwhile, some solutions integrate the antenna portion of the millimeter-wave radar chip into the chip itself, further improving the chip's integration level.

[0003] In existing technologies, front-facing radar and corner radar have different application scenarios, resulting in varying parameter requirements for illumination distance, angle, and resolution. Typically, front-facing radar and corner radar use different radar RF chips to better match the usage needs of different scenarios and achieve a balance between performance and cost. Some solutions use the same millimeter-wave radar chip, adjusting the antenna's RF parameters by changing the antenna shape, etc., to meet the application requirements of different scenarios such as front-facing radar and corner radar.

[0004] However, with technological advancements and the emergence of on-chip antenna technology, the shape of the antenna is fixed at the time of manufacture of the millimeter-wave radar chip. It is impossible to change the radio frequency parameters by adjusting the shape of the antenna on the PCB board, making it difficult to meet the application requirements of various scenarios. Summary of the Invention

[0005] To address the problems in existing technologies, this invention proposes an on-chip antenna structure for a millimeter-wave radar chip and its adjustment method. This solution provides a method for adjusting the length and shape of the on-chip antenna during chip fabrication. This not only meets the parameter adjustment requirements for changing application scenarios such as front radar and corner radar, but also allows for batch-wise fine-tuning of the antenna shape to accommodate differences in the actual positional layout of different vehicle models.

[0006] The technical solution proposed in this invention is as follows:

[0007] On one hand, this invention proposes an on-chip antenna structure for a millimeter-wave radar chip, including a built-in pressure cavity, a metal cavity pipe, a low-melting-point metal, and a first lead; the built-in pressure cavity and the metal cavity pipe are interconnected at one end, the metal cavity pipe is horizontal, and the other end forms an external pressure adjustment outlet, which is connected to the external atmosphere before antenna adjustment is completed; the low-melting-point metal is located inside the built-in pressure cavity and the metal cavity pipe, forming a metal antenna; the built-in pressure cavity has a cavity at the end away from the metal cavity pipe, and the metal cavity pipe also has a cavity at the end of the external pressure adjustment outlet, the cavity at the outlet being connected to the external atmosphere before antenna adjustment is completed; the millimeter-wave radar chip includes a radio frequency unit, the low-melting-point metal in the built-in pressure cavity is connected to the first lead, and the first lead is connected to the radio frequency unit of the millimeter-wave radar chip through a solder ball; the melting point of the low-melting-point metal is lower than the melting point of the solder ball.

[0008] On the other hand, the present invention proposes a method for adjusting the antenna length of the above-mentioned on-chip antenna structure, comprising:

[0009] The on-chip antenna structure is fabricated, and the required antenna length is determined based on the radio frequency parameters required by the millimeter-wave radar chip.

[0010] The on-chip antenna structure is placed in a sealed cavity, and the internal temperature of the cavity is adjusted to between the melting point of the low-melting-point metal and the melting point of the solder ball by introducing hot gas into the cavity, so that the low-melting-point metal melts into a liquid state.

[0011] Ensure the external air pressure adjustment outlet is not blocked, connect the sealed cavity to the air pressure regulating device, and adjust the air pressure inside the sealed cavity through the air pressure regulating device to extend or shorten the liquid low-melting-point metal along the metal cavity pipe to the required antenna length; when the low-melting-point metal stops extending or shortening, keep the external air pressure constant, reduce the internal temperature of the cavity to below the melting point of the solder ball, so that the low-melting-point metal turns into a solid, and at the same time block the external air pressure adjustment outlet, thus obtaining the on-chip antenna structure used for the millimeter-wave radar chip.

[0012] The present invention has the following beneficial effects:

[0013] The solution described in this invention allows for dynamic adjustment of the length and shape of the on-chip antenna during the early stages of chip manufacturing. This enables dynamic adjustment of the antenna's specifications during the manufacturing process, providing a flexible and adaptable production method for millimeter-wave radar chips with on-chip antennas to meet diverse needs. This improves production efficiency and satisfies the adjustable RF parameters required for various application scenarios. Furthermore, this invention eliminates the need for multiple chip fabrication steps while satisfying personalized RF parameters, significantly reducing the cost of chip customization and improving the efficiency and effectiveness of on-chip antenna customization for millimeter-wave radar. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the on-chip antenna structure of the millimeter-wave radar chip of the present invention;

[0015] Figure 2 This is a top perspective view of the on-chip antenna structure of the millimeter-wave radar chip of the present invention. Detailed Implementation

[0016] The present invention will be further described and illustrated below with reference to specific embodiments. The embodiments described are merely examples of the content of this disclosure and do not limit the scope of the invention. The technical features of each embodiment in the present invention can be combined accordingly, provided that there is no mutual conflict.

[0017] This invention proposes an on-chip antenna structure for a millimeter-wave radar chip, including a built-in pneumatic cavity 201, a metal cavity channel 202, a low-melting-point metal 203, and an antenna lead 207.

[0018] The on-chip antenna structure is implemented on the millimeter-wave radar chip 1; the millimeter-wave radar chip 1 is connected to the PCB substrate by solder balls; the built-in air pressure cavity 201 and the metal cavity pipe 202 are connected, and the interior contains low melting point metal 203, which is connected to the millimeter-wave radar chip 1 through antenna leads 207 and solder balls.

[0019] To better understand the above technical solutions, the following will provide a detailed description of the technical solutions in conjunction with the accompanying drawings and specific embodiments.

[0020] An on-chip antenna structure for a millimeter-wave radar chip, such as Figure 1 As shown, located above the radar chip, it includes a built-in air pressure cavity 201, a metal cavity pipe 202, a low melting point metal 203, an external air pressure adjustment outlet 204, an antenna package 205, a metal substrate 206, an antenna lead 207, and a solder ball 208.

[0021] The millimeter-wave radar chip 1 includes a computing unit, a radio frequency unit, etc., which are connected to the PCB substrate by solder balls.

[0022] In the on-chip antenna structure, the built-in air pressure cavity 201 and the metal cavity pipe 202 are interconnected, such as Figure 2As shown. The metal cavity pipe 202 is connected to the external atmosphere through the external air pressure adjustment outlet 204. The built-in air pressure cavity 201 and the metal cavity pipe 202 contain a low-melting-point metal 203, and a cavity is left at the end of the built-in air pressure cavity 201 away from the metal cavity pipe 202, which is sealed by the low-melting-point metal 203; a cavity is also left at the end of the metal cavity pipe 202 at the external air pressure adjustment outlet 204, which is connected to the outside. The low-melting-point metal 203 forms a metal antenna within the built-in air pressure cavity 201 and the metal cavity pipe 202. The portion of the low-melting-point metal 203 within the built-in air pressure cavity 201 is connected to the antenna lead 207, and the antenna lead 207 is connected to the radio frequency unit circuit of the radar chip 1 through the solder ball 208.

[0023] The antenna package 205 may be made of unshielded materials such as engineering plastics. The metal substrate 206 is placed between the antenna package 205 and the radar chip, serving as the antenna's radio frequency reference ground. The metal substrate 206 is connected to the solder ball 208 via antenna leads 207, and subsequently connected to the GND node of the radar chip 1 below. The antenna leads 207 connecting the metal substrate 206 and the antenna leads 207 connecting the low-melting-point metal 203 are not the same lead and are independent of each other.

[0024] The melting point of the low-melting-point metal 203 is lower than that of the tin ball. In this embodiment, a tin-bismuth alloy (melting point around 138°C) can be used, or a metal alloy containing low-melting-point materials such as tin, bismuth, and lead can be used to facilitate adjustment of the antenna length.

[0025] The metal cavity conduit 202 can be a straight conduit or a multi-branch conduit, depending on the required antenna type. For a multi-branch conduit, it consists of multiple branch conduits, all of which converge at one end and connect to the built-in air pressure cavity 201. Each branch conduit's other end forms an external air pressure adjustment outlet 204, such as... Figure 2 As shown.

[0026] Furthermore, during the fabrication process of the aforementioned chip, an antenna length adjustment process is added. By controlling the length and shape of the metal along a specific path, the antenna performance is adjusted to match the requirements of the radar chip below. The specific adjustment method for the aforementioned millimeter-wave radar chip with adjustable on-chip antenna is as follows:

[0027] Based on the radio frequency parameters required by the millimeter-wave radar chip, the on-chip antenna of the chip was simulated and experimentally adjusted to finally determine the required antenna length; the radio frequency parameters include transmit power, receive power, operating frequency, etc.

[0028] Let the melting point of the low-melting-point metal be T. A The melting point of the solder ball is T. BDuring the antenna fabrication process, after the on-chip antenna structure described above is initially fabricated, the on-chip antenna structure is placed in the high-temperature chamber of a sealed reflow oven, and the oven temperature is set to T. A1 T B <T A1 <T A The reflow oven heats the antenna structure on the chip with hot air, causing the low-melting-point metal to melt while the solder balls do not melt; at this time, the cavity pressure of the built-in air pressure chamber 201 is P. A0 ;

[0029] The reflow furnace is equipped with an adjustable air pump. While the metal inside is molten, it is ensured that the external air pressure adjustment outlet of the pipe containing the section to be adjusted is not blocked. The air pump is used to evacuate or purge the furnace to adjust the internal air pressure to P. BS1 At this time, since the external pressure adjustment outlet 204 is connected to the outside atmosphere, the pressure at the external pressure adjustment outlet 204 is also P. BS1 ;

[0030] Subject to P A0 P BS1 Due to the influence of the pressure difference, the displacement of the low-melting-point metal 203 inside the metal cavity pipe 202 changes:

[0031] (1) When P A0 >P BS1 At that time, the liquid low-melting-point metal 203 extends along the metal cavity pipe 202 towards the outlet side, and the cavity pressure of the built-in gas pressure chamber 201 is controlled by P. A0 Reduced to P A1 When P A1 =P BS1 At that time, the liquid metal stops moving;

[0032] At this point, keep P BS1 Keep the temperature unchanged, then lower it to the melting point T of the solder ball. B Next, the liquid low-melting-point metal 203 turns into a solid and its shape is fixed. At the same time, the external air pressure adjustment outlet 204 is blocked to keep the air pressure in the two cavities of the built-in air pressure chamber 201 and the metal cavity pipe 202 consistent.

[0033] (2) When P A0 <P BS1 At this time, the liquid low-melting-point metal 203 shortens along the metal cavity pipe 202 towards the built-in pneumatic cavity 201, and the cavity pressure of the built-in pneumatic cavity 201 is changed from P A0 Increase to P A2 When P A2 =P BS1 At that time, the liquid metal stops moving;

[0034] By adjusting P BS1The size is sufficient to allow the liquid metal to reach the required antenna length; after the liquid metal stops moving, maintain P. BS1 Keep the temperature unchanged, then lower it to the melting point T of the solder ball. B Next, the liquid low-melting-point metal 203 turns into a solid and its shape is fixed. At the same time, the external air pressure adjustment outlet 204 is blocked to keep the air pressure in the two cavities of the built-in air pressure chamber 201 and the metal cavity pipe 202 consistent.

[0035] The above method can be used to adjust the length of the antenna inside the on-chip antenna element (the shape is pre-placed according to a preset channel, and is not limited to a single straight shape), thereby fine-tuning the antenna's radio frequency parameters.

[0036] For the multi-branched metal cavity channel 202, the length of the metal in each branch channel can be adjusted sequentially using the above method, thereby completing the length adjustment of the multi-branched antenna.

[0037] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. Those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. An on-chip antenna structure for a millimeter-wave radar chip, characterized in that, It includes a built-in pneumatic chamber, a metal cavity pipe, a low-melting-point metal, and a first lead wire; The built-in air pressure cavity is connected to one end of the metal cavity pipe, which is horizontal in direction. The other end forms an external air pressure adjustment outlet, which is connected to the outside atmosphere before the antenna adjustment is completed. The low-melting-point metal is located inside the built-in air pressure cavity and the metal cavity pipe to form a metal antenna; the built-in air pressure cavity has a cavity at the end away from the metal cavity pipe, and the metal cavity pipe also has a cavity at the end of the external air pressure adjustment outlet. The cavity at the outlet is connected to the external atmosphere before the antenna adjustment is completed. The millimeter-wave radar chip includes a radio frequency unit, and a low-melting-point metal in the built-in pneumatic cavity is connected to the first lead. The first lead is used to connect the radio frequency unit of the millimeter-wave radar chip through a solder ball. The melting point of the low-melting-point metal is lower than that of the tin ball.

2. The on-chip antenna structure according to claim 1, characterized in that, The low-melting-point metal is a metal with a melting point below 230°C.

3. The on-chip antenna structure according to claim 1, characterized in that, The metal cavity pipe is composed of multiple sub-pipes, one end of each sub-pipe is converging together and communicating with the built-in air pressure cavity, and the other end of each sub-pipe forms an external air pressure adjustment outlet.

4. The on-chip antenna structure according to claim 1, characterized in that, The on-chip antenna structure also includes an antenna package, a metal substrate, and a second lead. The antenna package is used to encapsulate the built-in gas pressure cavity, the metal cavity channel, the low melting point metal, and the first lead. The metal substrate is located between the antenna package and the millimeter-wave radar chip. The metal substrate is connected to the GND node of the millimeter-wave radar chip through the second lead, and a solder ball is provided at the connection point for fixation.

5. The on-chip antenna structure according to claim 4, characterized in that, The antenna package is made of engineering plastic.

6. The on-chip antenna structure according to claim 1, characterized in that, The external air pressure adjustment outlet is closed after the antenna adjustment is completed.

7. A method for adjusting the antenna length of the on-chip antenna structure according to claim 1, characterized in that, The methods include: The on-chip antenna structure is fabricated, and the required antenna length is determined based on the radio frequency parameters required by the millimeter-wave radar chip. The on-chip antenna structure is placed in a sealed cavity, and the internal temperature of the cavity is adjusted to between the melting point of the low-melting-point metal and the melting point of the solder ball by introducing hot gas into the cavity, so that the low-melting-point metal melts into a liquid state. Ensure the external air pressure adjustment outlet is not blocked, connect the sealed cavity to the air pressure regulating device, and adjust the air pressure inside the sealed cavity through the air pressure regulating device to extend or shorten the liquid low-melting-point metal along the metal cavity pipe to the required antenna length; when the low-melting-point metal stops extending or shortening, keep the external air pressure constant, reduce the internal temperature of the cavity to below the melting point of the solder ball, so that the low-melting-point metal turns into a solid, and at the same time block the external air pressure adjustment outlet, thus obtaining the on-chip antenna structure used for the millimeter-wave radar chip.

8. The antenna length adjustment method according to claim 7, characterized in that, If the metal cavity pipe is composed of multiple sub-pipes, the length of the low-melting-point metal in each sub-pipe is adjusted sequentially, and other sub-pipes are blocked during the adjustment process.

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