Four-chip cascade microstrip array antenna system

Abstract

The invention provides a four-chip cascaded microstrip array antenna system, which comprises a dielectric substrate, antenna arrays arranged on the dielectric substrate, the antenna arrays are distributed in a rectangular shape, adopt a microstrip comb-shaped planar array antenna structure and are connected through a one-to-two microstrip power divider, and an SIW feeder network connected between the antenna arrays and millimeter wave radar chips. Due to the fact that the square MIMO sparse array layout is formed in the horizontal direction and the pitching direction, the maximum space utilization rate, the maximum aperture and the minimum mutual coupling effect can be achieved, miniaturization and structure compactness of the array antenna are achieved through the four-chip cascade connection mode, and the antenna has the advantages of being simple in structure, low in cost and easy to popularize. The radar system is more easily integrated with a chip and a digital circuit system, the complexity and the cost of the whole system are reduced, and compared with the prior art, the radar system has the advantages of higher 4D point cloud imaging capability, farther target detection distance, low side lobe, high angle resolution, multi-target tracking, high integration level and the like.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, in particular to the field of millimeter wave radar technology, and in particular to a four-chip cascaded microstrip array antenna system. Background Art

[0002] With the development of autonomous driving technology, the demand for accurate perception of the vehicle's surrounding environment is increasing. Traditional millimeter-wave radar can provide information in three dimensions: distance, speed, and angle, but in complex driving scenarios, especially in urban environments, this information may not be enough to ensure safe and reliable autonomous driving functions.

[0003] Traditional millimeter-wave radars have the disadvantages of insufficient pitch resolution, limited target recognition capabilities, and poor environmental adaptability. In recent years, 4D millimeter-wave radars have received widespread attention due to their significant advantages in autonomous driving systems. Compared with traditional millimeter-wave radars, 4D cascade radars use more receiving and transmitting antennas, add virtual channels, and greatly improve the resolution, confidence, and detection range (such as distance and FOV) of target detection. In addition to improving the target resolution in the horizontal plane, it also has target resolution in the pitch direction. 4D millimeter-wave radars add the dimension of height information, allowing radars to provide richer data. Specific advantages include but are not limited to: higher pitch resolution, enhanced target classification capabilities, optimized distance and angle accuracy, better environmental adaptability, and lower cost-effectiveness.

[0004] Therefore, 4D millimeter-wave radar has become an important trend in the development of intelligent driving technology because of the more comprehensive and accurate information it provides in autonomous driving vehicles. Summary of the invention

[0005] In view of this, the present invention provides a four-chip cascaded microstrip array antenna system, which has the advantages of higher 4D point cloud imaging capability, farther target detection distance, high angular resolution, multi-target tracking capability and high integration, can further improve spatial resolution and detection efficiency, is more miniaturized and integrated, and further improves stability, reliability and accuracy.

[0006] An embodiment of the present invention provides a four-chip cascaded microstrip array antenna system, the system comprising:

[0007] dielectric substrate;

[0008] The antenna array is distributed in a rectangular shape on the dielectric substrate, and the antenna array adopts a microstrip comb-shaped planar array antenna structure and is connected through a one-to-two microstrip power divider;

[0009] A feeder network is connected between the antenna array and the millimeter-wave radar chip, and the millimeter-wave radar chip is connected via a one-to-two-to-four power divider.

[0010] Furthermore, the antenna array includes transmitting antennas and receiving antennas, the number of the transmitting antennas is 12, the number of the receiving antennas is 16, and the antenna array is a 2×10 microstrip comb-shaped planar structure.

[0011] Furthermore, the feeder network adopts a substrate integrated waveguide SIW feeder network, one end of the feeder network is connected to the antenna array through a microstrip ladder structure, and the other end is connected to the millimeter wave radar chip through a balun.

[0012] Furthermore, the number of millimeter-wave radar chips is four, and each of the millimeter-wave radar chips is configured with three transmitters and four receivers, and is connected to the antenna array through a SIW feeder network.

[0013] Furthermore, the system also includes metal shielding covers, respectively covering the four millimeter-wave radar chips, and the four shielding covers have the same geometric structure and are arranged in sequence by rotating 90°.

[0014] Furthermore, a circle of grounding holes is respectively arranged around the periphery of each of the metal shielding covers.

[0015] Furthermore, the metal shielding cover includes: a separate shielding cover upper cover and a separate shielding cover base that cooperate with each other to form a cavity, the millimeter-wave radar chip is located in the cavity, and an absorbing material is provided on the side of the shielding cover upper cover facing the millimeter-wave radar chip.

[0016] Furthermore, metallized vias are arranged around the channel where the balun is located, and metal copper foil is arranged above the vias.

[0017] Furthermore, a circle of grounding holes is arranged around the dielectric substrate.

[0018] Furthermore, the receiving antenna is composed of horizontally arranged receiving antennas RX1~RX16, wherein RX1~RX8 are arranged in a mirror-symmetrical manner with RX9~RX16 as a whole, and the transmitting antenna includes horizontally arranged TX1 and TX2, TX4 and TX5, TX8 and TX9, TX11 and TX12, and vertically arranged TX3, TX6, TX7, and TX10.

[0019] The technical solution provided by the present invention adopts a MIMO sparse array layout in both horizontal and elevation directions, thereby significantly improving the spatial resolution and detection efficiency of the radar system, ensuring accurate recognition and tracking of target objects; by using a four-chip cascade method, the miniaturization and compactness of the array antenna are achieved, while ensuring long-distance and high-precision detection capabilities. This design makes the radar system easier to integrate with chips and digital circuit systems, reducing the complexity and cost of the overall system; the low sidelobe antenna design scheme is adopted to effectively avoid the generation of grating lobe effects, reduce the appearance of ghost targets, and improve the accuracy and reliability of the radar system; the metal scheme is arranged around the channel where the balun is located and the via hole to significantly increase the isolation between the balun channels, effectively improving the performance of the entire system. , ensuring the stable operation of the radar system in a complex electromagnetic environment; the feeder adopts a SIW structure, which effectively reduces the radiation of the feeder, makes the radiation pattern smoother, reduces the influence of the microstrip transmission line on the radiation pattern, and further improves the detection accuracy and stability of the radar system; the radar shield is fully grounded, providing a better electromagnetic shielding effect, effectively isolating the radio frequency interference generated by the chip end to the antenna, and ensuring the electromagnetic compatibility and signal integrity of the radar system; the shielding cover solution with a split design effectively solves the problem of heat collection and pressure collection in the shielding cover cavity, reduces the risk of high temperature to the structure during welding, and improves the reliability and service life of the radar system; the system not only achieves excellent electromagnetic compatibility (EMC), but also enhances signal integrity, ensuring the reliability and stability of high-frequency signal transmission. This multi-level grounding strategy provides a solid guarantee for the lossless transmission of signals in a complex electromagnetic environment, further improving the overall performance of the radar system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of a four-chip cascaded microstrip array antenna system provided by an embodiment of the present invention;

[0021] Figure 2 is a return loss simulation diagram of a four-chip cascaded microstrip array antenna system provided by an embodiment of the present invention;

[0022] Figure 3 This is a TX isolation simulation diagram of a four-chip cascaded microstrip array antenna system provided by an embodiment of the present invention;

[0023] Figure 4 This is a simulation diagram of the RX isolation of a four-chip cascaded microstrip array antenna system provided by an embodiment of the present invention;

[0024] Figure 5 This is a simulation diagram of the isolation between the transmitting and receiving antennas of the four-chip cascaded microstrip array antenna system provided by an embodiment of the present invention;

[0025] Figure 6This is a simulation diagram of the TX4 antenna pattern of a four-chip cascaded microstrip array antenna system provided by an embodiment of the present invention;

[0026] Figure 7 This is a simulation diagram of the RX10 antenna direction of the four-chip cascaded microstrip array antenna system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Embodiment 1

[0029] See also Figure 1 , Figure 1 1 is a schematic diagram of a four-chip cascaded microstrip array antenna system provided in an embodiment of the present invention. The four-chip cascaded microstrip array antenna system includes a dielectric substrate 11, an antenna array 12 and a feeder network 13.

[0030] Among them, the antenna array 12 is arranged in a rectangular distribution on the dielectric substrate, the antenna array adopts a microstrip comb planar array antenna structure, and is connected through a one-to-two microstrip power divider; the feeder network 13 is connected between the antenna array 12 and the millimeter-wave radar chip 14, and the millimeter-wave radar chip is connected through a one-to-two and then four-to-one power divider.

[0031] In some embodiments, the antenna array 12 includes a transmitting antenna 121 and a receiving antenna 122, the number of transmitting antennas is 12, the number of receiving antennas is 16, and the microstrip comb plane is a 2×10 array antenna structure. Specifically, the receiving antenna is composed of horizontally arranged receiving antennas RX1 to RX16, wherein RX1 to RX8 are arranged in a mirror-symmetrical layout with RX9 to RX16 as a whole, and the transmitting antenna includes horizontally arranged TX1 and TX2, TX4 and TX5, TX8 and TX9, TX11 and TX12, and vertically arranged TX3, TX6, TX7, and TX10.

[0032] In some embodiments, the antenna array is arranged in a "U"-shaped array on a dielectric substrate, four millimeter-wave radar chips are distributed in the U-shaped antenna array, and a one-to-two-to-four power divider is arranged in the middle of the four millimeter-wave chips. The design of the "U"-shaped antenna array can maximize the antenna aperture, minimize the mutual coupling effect, and optimize the vertical and horizontal resolution.

[0033] In some embodiments, the feeder network 13 adopts a substrate integrated waveguide SIW feeder network, one end of the feeder network is connected to the antenna array, and the other end is connected to the millimeter wave radar chip 14 through a balun (not shown). That is, the feeder network can be divided into a transmitting end feeder network and a receiving end feeder network, wherein one end of the transmitting end feeder network is connected to the transmitting antenna, and the other end is connected to the millimeter wave radar chip through a balun, and one end of the receiving end feeder network is connected to the receiving antenna, and the other end is connected to the millimeter wave radar chip through a balun.

[0034] In some embodiments, the number of millimeter-wave radar chips is four, and each of the millimeter-wave radar chips is configured with three transmitters and four receivers, and is connected to the antenna array through a SIW feeder network.

[0035] In some embodiments, the four millimeter-wave radar chips are respectively covered with metal shielding covers, and the geometric structures of the four metal shielding covers are the same, and they are arranged in sequence by rotating 90°. The present invention adopts a split design scheme, which can better solve the problem of heat collection and pressure collection in the metal shielding cover cavity, and at the same time play an electromagnetic shielding role to prevent EMC interference inside and outside the shielding cover. In other embodiments of the present invention, the metal shielding cover includes: a separate shielding cover upper cover and a separate shielding cover base that cooperate with each other to form a cavity, the millimeter-wave radar chip is located in the cavity, and an absorbing material is provided on the side of the shielding cover upper cover facing the millimeter-wave radar chip. Among them, the thickness of the absorbing material can be 0.5mm, and the shape can be a heptagon. The split shielding cover design is adopted to facilitate subsequent installation and maintenance, and effectively reduce the defective rate of the product. At the same time, the heptagonal absorbing material is provided on the inner wall of the shielding cover to optimize and improve the electromagnetic environment inside the shielding cover.

[0036] In some embodiments, a circle of grounding holes (not shown) are provided around the periphery of each metal shielding cover, and grounding is achieved through the grounding holes, thereby ensuring effective electromagnetic shielding between the metal shielding cover and the entire system, thereby significantly enhancing the electromagnetic isolation performance between the internal signal and the external environment.

[0037] In some embodiments, metal (not shown) is provided around the channels and vias where the SIW feeder network and the balun are located, for example, copper foil is provided in the channels on both sides of the SIW feeder and copper is coated on the inner wall of the via. Since there will be mutual coupling interference, surface wave interference, radiation interference, etc. between the feeders, the isolation between the channels is improved by designing ground holes, copper foil, etc., thereby reducing interference.

[0038] In some embodiments, a circle of grounding holes is provided around the dielectric substrate. This design can effectively suppress electromagnetic interference (EMI) and ensure that the signal on the antenna surface of the dielectric layer is strictly confined inside the dielectric layer. In addition, a circle of through holes 15 that penetrate the entire board layer is designed along the outer edge of the dielectric substrate. These through holes can not only optimize the grounding connection between the board layers to form a continuous and stable grounding plane, but also significantly suppress the interference signal leaked from the side of the board layer. In an embodiment of the present invention, the dielectric substrate board material is RO3003G2, and its thickness is 0.127mm.

[0039] In some embodiments, the SIW feeder network is connected to the antenna array via a microstrip ladder structure. The antenna array and the SIW feeder network are connected using a microstrip ladder structure. This design not only ensures efficient signal transmission, but also optimizes the impedance matching between the antenna and the feeder, reduces signal reflection and loss, and improves the overall performance of the radar system.

[0040] In order to verify the effect of the four-chip cascaded microstrip array antenna system provided by the embodiment of the present invention, the inventor of the present application conducted a large number of simulation experiments, please refer to Figures 2 to 7 ,in, Figure 2 is a return loss simulation diagram of a four-chip cascaded microstrip array antenna system provided by an embodiment of the present invention, Figure 3 is a TX isolation simulation diagram of a four-chip cascaded microstrip array antenna system provided by an embodiment of the present invention, Figure 4 is a simulation diagram of the RX isolation of a four-chip cascaded microstrip array antenna system provided by an embodiment of the present invention, Figure 5 is a simulation diagram of the isolation between the transmitting and receiving antennas of the four-chip cascaded microstrip array antenna system provided by an embodiment of the present invention, Figure 6 This is a simulation diagram of the TX4 antenna pattern of the four-chip cascaded microstrip array antenna system provided by an embodiment of the present invention. Figure 7 This is a simulation diagram of the RX10 antenna direction of the four-chip cascaded microstrip array antenna system provided in an embodiment of the present invention.

[0041] Figure 2 The return loss of the four-chip cascaded microstrip array antenna system of the present invention is demonstrated. In the 76-77 GHz frequency band, the return loss is greater than 13.38 dB, and the -10 dB impedance bandwidth is 3.81 GHz. It can be seen that the reflected energy is small, indicating that the impedance matching is good.

[0042] Figure 3 , Figure 4 , Figure 5The isolation curves of the transmitting antennas, the receiving antennas and the transceiver antennas of the present invention are shown respectively. From the simulation results, it can be seen that the transmitting antenna isolation is below -46.88dB, the receiving antenna isolation is below -42.87dB, and the transceiver antenna isolation is below -49.11dB. The above data shows that when working in the 76-77GHz frequency band, the mutual coupling effect between the transmitting antennas, the receiving antennas, and the transceiver antennas is small. The greater the isolation, the smaller the mutual coupling, and thus the smaller the impact on the overall performance of the antenna.

[0043] In view of the large amount of directional pattern data for 12 transmit and 16 receive antennas (the number of transmit antennas is 12 and the number of receive antennas is 16), Figure 6 and Figure 7 Only the gain pattern curves of the TX4 antenna and the RX10 antenna of the present invention are shown. From the simulation results, it can be seen that the half-power beamwidth of the antenna in azimuth is 43°, the half-power beamwidth of the elevation is 16°, and the sidelobe level is lower than -19.68dB, which has good low sidelobe characteristics.

[0044] By utilizing the technical solution provided by the present invention, the spatial resolution and detection efficiency of the radar system are significantly improved due to the adoption of MIMO sparse array layout in both horizontal and elevation directions, thereby ensuring accurate recognition and tracking of target objects; by means of four-chip cascade, the miniaturization and compactness of the array antenna are achieved, while ensuring long-distance and high-precision detection capabilities. This design makes it easier to integrate the radar system with the chip and digital circuit system, thereby reducing the complexity and cost of the overall system; the low sidelobe antenna design scheme is adopted to effectively avoid the generation of grating lobe effects, reduce the appearance of ghost targets, and improve the accuracy and reliability of the radar system; the metal scheme is arranged around the channel where the balun is located and in the via hole, thereby significantly increasing the isolation between the balun channels and effectively improving the performance of the entire system. The radar system can operate stably in a complex electromagnetic environment. The feeder adopts SIW structure, which effectively reduces the radiation of the feeder, makes the radiation pattern smoother, reduces the influence of microstrip transmission line on the radiation pattern, and further improves the detection accuracy and stability of the radar system. The radar shield realizes full grounding, provides better electromagnetic shielding effect, effectively isolates the radio frequency interference from the chip end to the antenna, and ensures the electromagnetic compatibility and signal integrity of the radar system. The shielding cover solution with split design effectively solves the problem of heat collection and pressure collection in the shielding cover cavity, reduces the risk of high temperature to the structure during welding, and improves the reliability and service life of the radar system. The system not only achieves excellent electromagnetic compatibility (EMC), but also enhances signal integrity, ensuring the reliability and stability of high-frequency signal transmission. This multi-level grounding strategy provides a solid guarantee for the lossless transmission of signals in complex electromagnetic environments, and further improves the overall performance of the radar system.

[0045] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A four-chip cascaded microstrip array antenna system, characterized in that: The system comprises: dielectric substrate; The antenna array is distributed in a rectangular shape on the dielectric substrate, and the antenna array adopts a microstrip comb-shaped planar array antenna structure and is connected through a one-to-two microstrip power divider; A feeder network is connected between the antenna array and the millimeter-wave radar chip, and the millimeter-wave radar chip is connected via a one-to-two-to-four power divider.

2. The system according to claim 1, characterized in that The antenna array includes transmitting antennas and receiving antennas. The number of the transmitting antennas is 12, the number of the receiving antennas is 16, and the antenna array is a 2×10 microstrip comb-shaped planar structure.

3. The system according to claim 1, characterized in that The feeder network adopts a substrate integrated waveguide (SIW) feeder network, one end of the feeder network is connected to the antenna array through a microstrip ladder structure, and the other end is connected to the millimeter wave radar chip through a balun.

4. The system according to claim 3, characterized in that There are four millimeter-wave radar chips, each of which is configured with three transmitters and four receivers and is connected to the antenna array through a SIW feeder network.

5. The system according to claim 4, characterized in that The system also includes metal shielding covers, respectively covering the four millimeter-wave radar chips, and the four metal shielding covers have the same geometric structure and are arranged in sequence by rotating 90 degrees.

6. The system according to claim 5, characterized in that A circle of grounding holes is respectively arranged around the periphery of each metal shielding cover.

7. The system according to claim 5, characterized in that The metal shielding cover comprises: a separate shielding cover upper cover and a separate shielding cover base which cooperate with each other to form a cavity, the millimeter wave radar chip is located in the cavity, and a wave absorbing material is provided on a side of the shielding cover upper cover facing the millimeter wave radar chip.

8. The system according to claim 3, characterized in that Metallized vias are arranged around the SIW feeder network and the channel where the balun is located, and metal copper foil is arranged above the vias.

9. The system according to claim 1, characterized in that A circle of grounding holes is arranged around the dielectric substrate.

10. The system according to claim 2, characterized in that The receiving antenna is composed of horizontally arranged receiving antennas RX1 to RX16, wherein RX1 to RX8 are arranged in a mirror-symmetrical manner with RX9 to RX16 as a whole, and the transmitting antenna includes horizontally arranged TX1 and TX2, TX4 and TX5, TX8 and TX9, TX11 and TX12, and vertically arranged TX3, TX6, TX7, and TX10.

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