Sparse array millimeter wave imaging radar

Abstract

The utility model relates to a sparse array millimeter wave imaging radar which comprises a dielectric substrate and a radar array fixedly arranged on one surface of the dielectric substrate. The radar array comprises N radar units which are transversely arranged at equal intervals; each radar unit comprises a radar chip, a transmitting antenna array and a receiving antenna array; the transmitting antenna arrays and the receiving antenna arrays of the two adjacent radar units are distributed on the upper side and the lower side of the radar chip in a crossed manner, and the transmitting antenna arrays and the receiving antenna arrays of the two adjacent radar units are distributed on the upper side and the lower side of the radar chip in a crossed manner. Moreover, the transmitting antenna arrays and the receiving antenna arrays of the adjacent radar units are distributed in a crossed manner, thereby effectively improving the imaging resolution and performance of the radar, and reducing the mutual coupling effect between the antenna units.

Description

Technical Field

[0001] The utility model belongs to the field of millimeter wave radar imaging, in particular to a sparse array millimeter wave imaging radar. Background Art

[0002] With the rapid development of science and technology, millimeter-wave imaging radar technology has demonstrated tremendous application potential and value in numerous fields, including autonomous driving, intelligent security, industrial inspection, and medical imaging. With its unique advantages, such as excellent penetration, all-weather operation, and high resolution, millimeter-wave radar has become a key technology in these fields.

[0003] However, traditional millimeter-wave radar array design often faces several challenges and limitations. First, achieving high resolution and imaging quality typically requires a large number of antenna elements, which increases system complexity and costs, and hinders system integration and miniaturization. Second, dense antenna array layouts can cause mutual interference, impacting radar performance and stability.

[0004] To overcome these shortcomings, sparse array technology has emerged. By reducing the number of antenna elements and optimizing their layout, sparse arrays can reduce system complexity and cost while maintaining imaging quality. However, how to effectively design sparse arrays to achieve high-performance millimeter-wave imaging remains an urgent problem.

[0005] Existing sparse array millimeter-wave imaging radars often have the following design deficiencies:

[0006] Improper antenna layout: Although some designs reduce the number of antenna elements, they fail to fully utilize the advantages of sparse arrays, resulting in reduced imaging resolution and performance.

[0007] Obvious mutual coupling effect: The spacing between antenna units is too close, which easily produces a strong mutual coupling effect, affecting the detection accuracy and stability of the radar.

[0008] Low system integration: Some designs fail to fully consider the system's integration and miniaturization requirements, resulting in large and expensive radar systems. Utility Model Content

[0009] To address the problems described in the background art, the present invention provides a sparse array millimeter-wave imaging radar, comprising: a dielectric substrate; and a radar array fixedly mounted on a surface of the dielectric substrate; the radar array comprises N radar units arranged equidistantly and laterally; each radar unit comprises: a radar chip, a transmitting antenna array, and a receiving antenna array; the transmitting antenna arrays and receiving antenna arrays of two adjacent radar units are arranged in a cross pattern above and below the radar chip.

[0010] Preferably, the transmitting antenna array includes L transmitting antennas arranged horizontally at equal distances, and the radar chip and the L transmitting antennas are connected through a microstrip line; the receiving antenna array includes K receiving antennas arranged horizontally at equal distances, and the radar chip and the K receiving antennas are connected through a microstrip line.

[0011] Preferably, the spacing between two adjacent transmitting antennas in the transmitting antenna array is 4 times the wavelength, and the spacing between two adjacent receiving antennas in the receiving antenna array is 1 time the wavelength; from left to right, the spacing between the first transmitting antenna of the transmitting antenna array in each radar unit and the last receiving antenna of the receiving antenna array in the previous radar unit is 1 / 2 times the wavelength; from left to right, the distance between the first receiving antenna of the receiving antenna array in each radar unit and the last transmitting antenna of the transmitting antenna array in the previous radar unit is 1 / 2 times the wavelength.

[0012] Preferably, a microusb connector and an FMC connector are fixedly provided on the dielectric substrate; the microusb connector and the radar chips of the N radar units are connected through a metal conductor; and the FMC connector and the radar chips of the N radar units are connected through a metal conductor.

[0013] Preferably, the radar chip adopts the IWR6843 millimeter wave radar chip.

[0014] Preferably, the dielectric substrate is made of RO4835 high-frequency plate, the thickness of the RO4835 high-frequency plate is 10 mil, and the dielectric constant is Er=3.66.

[0015] Preferably, the width of the microstrip line meets the following conditions:

[0016]

[0017] Where Er represents the dielectric constant of the dielectric substrate, H represents the thickness of the dielectric substrate, W represents the line width of the microstrip line, T represents the thickness of the microstrip line copper, and Z0 represents the impedance of the microstrip line.

[0018] The utility model has at least the following beneficial effects

[0019] This utility model effectively improves the imaging resolution and performance of the radar by distributing the transmitting antenna arrays and receiving antenna arrays of two adjacent radar units in a cross shape on the upper and lower sides of the radar chip, and reasonably designs the antenna spacing. At the same time, it increases the distance between the transmitting antenna arrays and receiving antenna arrays of different radar units, reduces the mutual coupling effect between the antenna units, and improves the detection accuracy and stability of the radar. The use of microUSB connectors and FMC connectors realizes convenient connection between the radar chip and external devices. At the same time, the use of high-frequency plates as dielectric substrates further improves the integration and miniaturization of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model;

[0021] Figure 2 Schematic diagram of the antenna array of the present utility model;

[0022] Figure 3 This is a schematic diagram of the use process of the utility model. DETAILED DESCRIPTION

[0023] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention. The following embodiments and the features in the embodiments can be combined with each other without conflict.

[0024] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0025] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0026] See also Figure 1 and Figure 2 The present invention provides a sparse array millimeter-wave imaging radar, comprising: a dielectric substrate, and a radar array fixedly arranged on a surface of the dielectric substrate; the radar array comprises N radar units arranged laterally at equal intervals; each radar unit comprises: a radar chip, a transmitting antenna array, and a receiving antenna array; the transmitting antenna arrays and receiving antenna arrays of two adjacent radar units are distributed in a cross-shaped manner on the upper and lower sides of the radar chip.

[0027] In this application, the transmitting antenna arrays and receiving antenna arrays of two adjacent radar units are distributed in a cross shape on the upper and lower sides of the radar chip. This design effectively utilizes the space around the radar chip and improves space utilization. At the same time, it also makes the integration of the entire radar array higher, which is conducive to reducing the volume and weight of the radar system. By cross-distributing the transmitting antenna array and the receiving antenna array, the distance between the transmitting antenna arrays and the receiving antenna arrays of different radar units is increased, the mutual coupling effect between the antenna units is reduced, and the electromagnetic interference between the antennas can be reduced to a certain extent. This layout helps to improve the electromagnetic compatibility of the radar system and improve the detection accuracy and stability of the signal.

[0028] Preferably, the transmitting antenna array includes L transmitting antennas arranged horizontally at equal distances, and the radar chip and the L transmitting antennas are connected through a microstrip line; the receiving antenna array includes K receiving antennas arranged horizontally at equal distances, and the radar chip and the K receiving antennas are connected through a microstrip line.

[0029] In this embodiment, the radar chip is connected to the transmitting and receiving antennas via microstrip lines. This connection method offers the advantages of low loss, high integration, and ease of fabrication. Microstrip lines effectively transmit high-frequency signals, ensuring stable and reliable performance of the radar system.

[0030] In this embodiment, the radar chip uses the IWR6843 millimeter-wave radar chip with 3 transmitters and 4 receivers. Therefore, the transmitting antenna array in each radar unit includes 3 transmitting antennas, and the receiving antenna array includes 4 receiving antennas. According to the layout of the transmitting antenna array and the receiving antenna array in this embodiment, 48 points can be covered in the horizontal direction, with a width of:

[0031]

[0032] The center frequency of the IWR6843 millimeter wave radar chip is 62GHz, which is the operating frequency f0. The speed of light c is 3×10 8 m / s, then the wavelength is:

[0033]

[0034] Therefore, the horizontal coverage range is 115.92 mm. If N pieces are cascaded, the horizontal coverage range is 6·N·λ. The coverage range of millimeter-wave radar is relatively wide.

[0035] Preferably, the spacing between two adjacent transmitting antennas in the transmitting antenna array is 4 times the wavelength, and the spacing between two adjacent receiving antennas in the receiving antenna array is 1 time the wavelength; from left to right, the spacing between the first transmitting antenna of the transmitting antenna array in each radar unit and the last receiving antenna of the receiving antenna array in the previous radar unit is 1 / 2 times the wavelength; from left to right, the distance between the first receiving antenna of the receiving antenna array in each radar unit and the last transmitting antenna of the transmitting antenna array in the previous radar unit is 1 / 2 times the wavelength.

[0036] In this embodiment, four radar units are taken as an example. The four radar units are arranged horizontally at equal distances on the dielectric substrate. From left to right, the transmitting antenna array of the first radar unit is set on the upper side of the radar unit, and the receiving antenna array is set on the lower side of the radar unit. The transmitting antenna array of the second radar unit is set on the lower side of the radar unit, and the receiving antenna array is set on the upper side of the radar unit; the transmitting antenna array of the third radar unit is set on the upper side of the radar unit, and the receiving antenna array is set on the lower side of the radar unit; the transmitting antenna array of the fourth radar unit is set on the lower side of the radar unit, and the receiving antenna array is set on the upper side of the radar unit; the transmitting antenna arrays and receiving antenna arrays of two adjacent radar units are distributed in a cross shape on the upper and lower sides of the radar chip.

[0037] In this embodiment, according to the two-dimensional plane geometric relationship, the above setting can make it possible that after the transmitting antenna transmits the signal, it is reflected by the object to the receiving antenna, and the projection middle positions of all reflection lines are sequentially spaced at 1 / 2 times the wavelength λ. For example, the projection middle position of the reflection line from the first transmitting antenna to the fourth receiving antenna in the first radar unit is defined as point A, and the projection middle position of the reflection line from the second transmitting antenna to the first receiving antenna is defined as point B. Point A and point B are two adjacent middle points, so the spacing between point A and point B is 1 / 2 times the wavelength λ. This middle position is the equivalent position of the object reflection point. According to the above formula It can be seen that with this arrangement, the millimeter-wave radar imaging resolution is as high as 2.415mm.

[0038] Preferably, a microusb connector and an FMC connector are fixedly provided on the dielectric substrate; the microusb connector and the radar chips of the N radar units are connected through a metal conductor; and the FMC connector and the radar chips of the N radar units are connected through a metal conductor.

[0039] In one embodiment, the FMC is a high-speed signal connector used to control the sensor's operation and output the sensor's collected data. The FMC is connected to the four radar chips via high-speed PCB traces. A microUSB connector is used to power the sensor radar at a 5V supply voltage. The entire sensor has physical dimensions of 17cm x 10cm.

[0040] Preferably, the radar chip adopts the IWR6843 millimeter wave radar chip.

[0041] In the embodiment, the transmitting antenna array of the first radar unit includes transmitting antennas Tx1 to Tx3, and the receiving antenna array includes receiving antennas Rx1 to Rx4. The transmitting antenna array of the second radar unit includes transmitting antennas Tx4 to Tx6, and the receiving antenna array includes receiving antennas Rx5 to Rx8. The spacing between Tx3 and Rx5 is 1 / 2 times the wavelength, and the spacing between Rx4 and Tx4 is 1 / 2 times the wavelength.

[0042] In this embodiment, the distance between the first transmitting antenna of the transmitting antenna array in each radar chip and the last receiving antenna of the receiving antenna array in the previous radar chip is set to 1 / 2 wavelength; the distance between the first receiving antenna of the receiving antenna array in the radar chip and the last transmitting antenna of the transmitting antenna array in the previous radar chip is set to 1 / 2 wavelength. This ensures that when two adjacent radar chips collect data, the equivalent position of the last set of transmitting and receiving antennas in the previous radar chip is 1 / 2 wavelength away from the equivalent position of the first set of transmitting and receiving antennas in the next radar chip, thus ensuring equal sampling intervals. With this antenna arrangement, data is sampled every half wavelength, which not only ensures that data is not missed but also allows the use of fewer radar chips and antennas at the same imaging aperture, thereby reducing costs.

[0043] Preferably, the dielectric substrate is made of RO4835 high-frequency plate, the thickness of the RO4835 high-frequency plate is 10 mil, and the dielectric constant is Er=3.66.

[0044] Preferably, the width of the microstrip line meets the following conditions:

[0045]

[0046] Where Er represents the dielectric constant of the dielectric substrate, H represents the thickness of the dielectric substrate, W represents the line width of the microstrip line, T represents the thickness of the microstrip line copper, and Z0 represents the impedance of the microstrip line.

[0047] In this embodiment, impedance matching of the microstrip line is achieved by setting appropriate material selection and setting. In this embodiment, the characteristic impedance of the microstrip line is ensured to be 50Ω by setting the width of the microstrip line. In this way, when high-frequency radar signals are transmitted in the microstrip line, the problem of signal rebound caused by inconsistent characteristic impedance can be avoided.

[0048] The operating principle of this utility model:

[0049] First, when scanning the object to be measured and collecting data, the sensor should be connected to the external microprocessor (MPU) with an adapter board with an FMC connector to form a data path, and then the power supply should be connected with USB. The radar sensor is facing one side of the object to be measured. The MPU sends a pulse signal to make the first radar chip work. The first radar chip transmits electromagnetic waves through its first transmitting antenna. When there is an object in front, the electromagnetic waves will be reflected back and received by the four receiving antennas at the same time, thus completing 1 transmit and 4 receive. Similarly, the other two transmitting antennas of the radar chip will also transmit electromagnetic waves in time. When the first radar chip is finished, the MPU sends a pulse signal to the second radar chip, and the second radar chip starts to work in the same way until all radar chips in the horizontal direction have completed the transmission and reception operations. At this point, a horizontal scan is completed. Scan the object on the side in the horizontal direction, move the radar sensor in the vertical direction, and repeat the scan on the object on the side until the entire object is covered. The scanning diagram is shown as follows. Figure 3 shown.

[0050] In summary, the utility model effectively improves the imaging resolution and performance of the radar by distributing the transmitting antenna arrays and receiving antenna arrays of two adjacent radar units in a cross shape on the upper and lower sides of the radar chip, and reasonably designs the antenna spacing; at the same time, it increases the distance between the transmitting antenna arrays and receiving antenna arrays of different radar units, reduces the mutual coupling effect between the antenna units, and improves the detection accuracy and stability of the radar. The use of microUSB connectors and FMC connectors realizes convenient connection between the radar chip and external devices. At the same time, the use of high-frequency plates as dielectric substrates further improves the integration and miniaturization level of the system. The proposal of this solution is of great significance to promoting the development of sparse array millimeter-wave imaging radar technology, and is expected to provide more efficient, reliable and economical solutions for fields such as autonomous driving, intelligent security, and industrial detection.

[0051] The above description is only 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 in the scope of protection of the present invention.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and are not limiting. Although the utility model is described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the utility model.

Claims

1. A sparse array millimeter wave imaging radar, characterized in that: include: A dielectric substrate, and a radar array fixedly disposed on a surface of the dielectric substrate; The radar array comprises N radar units that are arranged laterally at equal distances; Each radar unit includes: a radar chip, a transmitting antenna array and a receiving antenna array; The transmitting antenna arrays and receiving antenna arrays of two adjacent radar units are distributed in a cross shape on the upper and lower sides of the radar chip.

2. The sparse array millimeter wave imaging radar according to claim 1, characterized in that: The transmitting antenna array includes L transmitting antennas arranged horizontally at equal distances, and the radar chip and the L transmitting antennas are connected via a microstrip line; the receiving antenna array includes K receiving antennas arranged horizontally at equal distances, and the radar chip and the K receiving antennas are connected via a microstrip line.

3. The sparse array millimeter wave imaging radar according to claim 2, characterized in that: The spacing between two adjacent transmitting antennas in the transmitting antenna array is 4 times the wavelength, and the spacing between two adjacent receiving antennas in the receiving antenna array is 1 time the wavelength; from left to right, the spacing between the first transmitting antenna in the transmitting antenna array of each radar unit and the last receiving antenna in the receiving antenna array of the previous radar unit is 1 / 2 times the wavelength; From left to right, the distance between the first receiving antenna of the receiving antenna array in each radar unit and the last transmitting antenna of the transmitting antenna array in the previous radar unit is 1 / 2 wavelength.

4. The sparse array millimeter wave imaging radar according to claim 1, characterized in that: A microUSB connector and an FMC connector are also fixedly provided on the dielectric substrate; the microUSB connector and the radar chips of the N radar units are connected through a metal conductor; and the FMC connector and the radar chips of the N radar units are connected through a metal conductor.

5. The sparse array millimeter wave imaging radar according to claim 1, characterized in that: The radar chip uses the IWR6843 millimeter wave radar chip.

6. The sparse array millimeter wave imaging radar according to claim 1, characterized in that: The dielectric substrate is made of RO4835 high-frequency plate, the thickness of the RO4835 high-frequency plate is 10 mil, and the dielectric constant is Er=3.

66.

7. The sparse array millimeter wave imaging radar according to claim 2, characterized in that: The width of the microstrip line meets the following conditions: Where Er represents the dielectric constant of the dielectric substrate, H represents the thickness of the dielectric substrate, W represents the line width of the microstrip line, T represents the thickness of the microstrip line copper, and Z0 represents the impedance of the microstrip line.

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