A millimeter wave waveguide radar antenna performance rapid test method and system

Abstract

This invention relates to the field of waveguide radar testing and discloses a rapid testing method and system for millimeter-wave waveguide radar antenna performance, comprising the following steps: fixing a PCBA (Printed Circuit Board Assembly) on a turntable inside a dark box; the PCBA integrating an RF chip; using a robotic arm inside the dark box to fix the waveguide antenna board under test onto the PCBA; the waveguide antenna board having waveguide ports corresponding one-to-one with the waveguide ports of the RF chip, the RF chip being connected to the waveguide antenna board through the waveguide ports; setting up a corner transmitter inside the dark box; activating the RF chip to transmit radar signals; receiving the echo signal from the corner transmitter to complete the radar antenna performance test. This invention provides a rapid testing method and system for millimeter-wave radar waveguide antenna performance, and the inclusion of a leakage-proof structure between the PCBA and the waveguide antenna board effectively ensures the stability and reliability of the waveguide antenna performance test.

Description

Technical Field

[0001] This invention relates to the field of waveguide radar testing, and in particular to a rapid testing method and system for millimeter-wave waveguide radar antenna performance. Background Technology

[0002] With the rapid development of ADAS technology, millimeter-wave radar is gradually shifting from traditional microstrip antennas to waveguide antennas. However, waveguide antennas are generally assembled from multiple layers. Unlike microstrip antennas, which only require precise dimensional control for specific high-frequency substrates to ensure antenna performance, waveguide antennas can degrade in performance even if the manufacturing dimensions are correct. Problems such as interlayer gaps, coating peeling, uneven coating, and missing coatings during assembly can lead to performance degradation. Once the waveguide antenna is assembled, it is difficult to inspect the internal gaps and coatings.

[0003] Currently, there are three common methods for testing waveguide antennas: First, using industrial CT scans. However, this method is very expensive and cannot effectively determine antenna performance. Second, using a low-frequency network analyzer. This involves adding spread spectrum modules to increase the number of antennas that can be tested at once. Therefore, the number of spread spectrum modules required corresponds to the number of waveguide antennas on the millimeter-wave radar antenna board, or a portion thereof. Performance testing of all waveguide antennas in the entire millimeter-wave radar is completed through group switching. This method suffers from both high equipment costs and time-consuming group switching, impacting the testing efficiency of the waveguide antenna board. Third, using a low-frequency network analyzer. This involves first using spread spectrum modules to extend the operating frequency band to the required high-frequency band, and then using high-frequency switches to alternately test each waveguide antenna of the millimeter-wave radar. This method also suffers from high equipment costs, poor isolation of the high-frequency switches, and a limited number of switching operations. Therefore, how to conveniently and efficiently test the antenna performance of waveguide antenna boards has become a pressing issue in millimeter-wave waveguide radar applications. Summary of the Invention

[0004] The main objective of this invention is to address the problems of high cost of testing equipment, poor isolation of high-frequency switches, and limited switching frequency in existing technologies. A rapid performance testing method for millimeter-wave waveguide radar antennas includes the following steps: fixing a PCBA (Printed Circuit Board Assembly) on a turntable inside a dark box; the PCBA integrating an RF chip; using a robotic arm inside the dark box to fix the waveguide antenna board under test onto the PCBA; the waveguide antenna board has waveguide ports that correspond one-to-one with the waveguide ports of the RF chip, and the RF chip is connected to the waveguide antenna board through the waveguide ports; setting up a corner transmitter inside the dark box; activating the RF chip to transmit radar signals; and receiving the echo signal from the corner transmitter to complete the radar antenna performance test.

[0005] As a preferred technical solution, the setting of the corner transmitter inside the dark box includes: fixing the corner reflector inside the dark box at a position at an appropriate distance from the waveguide antenna plate, and adjusting the height and horizontal position of the corner reflector so that the corner reflector is aligned with the geometric center of the waveguide antenna plate.

[0006] As a preferred technical solution, the inside of the dark box is lined with a 77GHz frequency absorbing material.

[0007] As a preferred technical solution, a boss is provided on the waveguide antenna board at all waveguide port positions corresponding to each chip. The boss is raised to an appropriate height above the periphery and has a smooth and flat surface. A rectangular groove with appropriate width and depth is provided on each waveguide port position on the boss. The width of the rectangular groove and the width of the sidewall depend on the distance between adjacent waveguide ports. The depth and width of the rectangular groove meet the requirements for suppressing the propagation of electromagnetic waves in a specific frequency band.

[0008] As a preferred technical solution, multiple regular polygon patches with equal side lengths are arranged around each waveguide port on the PCBA. The patches are spaced at the same distance, and a metallized via is arranged at the center of each patch. The metallized via connects the patch to the metal base plate disposed on the second metal layer of the PCB substrate.

[0009] A second aspect of this invention provides a rapid testing system for millimeter-wave waveguide radar antenna performance, comprising: a dark box; a PCBA, a turntable fixed inside the dark box, the PCBA integrating an RF chip; a waveguide antenna board, the waveguide antenna board having waveguide ports corresponding one-to-one with the waveguide ports of the RF chip, the RF chip being connected to the waveguide antenna board through the waveguide ports; a robotic arm, the robotic arm being disposed inside the dark box for fixing the waveguide antenna board to be tested onto the PCBA; a corner reflector, the corner reflector being disposed inside the dark box for reflecting radar signals emitted by the RF chip; a data processing module and a turntable control module, for controlling the turntable, starting the RF chip to emit radar signals, receiving the echo signals from the corner reflector, and completing the radar antenna performance test.

[0010] The present invention has the following beneficial effects:

[0011] This invention provides a rapid testing method and system for millimeter-wave radar waveguide antenna performance. A leakage prevention structure is set between the PCBA and the waveguide antenna board, which can effectively ensure the stability and reliability of waveguide antenna performance testing.

[0012] The present invention proposes a rapid testing method and system for millimeter-wave radar waveguide antenna performance. It does not require expensive testing equipment, the required testing environment is simple to set up, and it can utilize the millimeter-wave radar PCBA without additional design. The required test fixture has a simple structure and is easy to manufacture, thus saving testing costs to a certain extent.

[0013] The present invention proposes a rapid testing method and system for millimeter-wave radar waveguide antenna performance. This method and system is highly automated, fast and efficient, effectively improving the detection efficiency of waveguide antenna boards and reducing the production cost of radar. It can be used to quickly inspect the performance of waveguide antennas before assembly during mass production of waveguide antenna radars, and can also be used for outgoing and incoming inspection of waveguide antennas. Attached Figure Description

[0014] Figure 1 A schematic diagram of a rapid performance testing system for millimeter-wave radar waveguide antennas;

[0015] Figure 2 Schematic diagram of the anti-leakage structure of the waveguide port of a millimeter-wave waveguide antenna plate;

[0016] Figure 3 This is a schematic diagram of the leakage prevention structure for the waveguide port of a PCBA.

[0017] Figure 4 The simulation curve of the S21 curve for the anti-leakage structure of the waveguide port of the waveguide antenna board.

[0018] The attached figures are labeled as follows:

[0019] Dark box 1; PCBA 2, Turntable 3, Waveguide antenna board 4, Robotic arm 5, Corner reflector 6, Data processing module and turntable control module 7, Boss 41, Waveguide port 42, Rectangular slot 43, Patch 44, Corner reflector bracket 8. Detailed Implementation

[0020] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this invention 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.

[0021] This invention addresses the aforementioned task by providing a rapid performance testing method for millimeter-wave waveguide radar antennas, comprising the following steps: fixing a PCBA (Printed Circuit Board Assembly) on a turntable inside a dark box; the PCBA integrating an RF chip; using a robotic arm inside the dark box to fix the waveguide antenna board to be tested onto the PCBA; the waveguide antenna board having waveguide ports corresponding one-to-one with the waveguide ports of the RF chip, the RF chip being connected to the waveguide antenna board through the waveguide ports; setting up an angle transmitter inside the dark box; activating the RF chip to transmit radar signals; and receiving the echo signal from the angle transmitter to complete the radar antenna performance test.

[0022] This invention also relates to a rapid performance testing system for millimeter-wave waveguide radar antennas, comprising: a dark box; a PCBA, a turntable fixed inside the dark box, the PCBA integrating an RF chip; a waveguide antenna board, the waveguide antenna board having waveguide ports corresponding one-to-one with the waveguide ports of the RF chip, the RF chip being connected to the waveguide antenna board through the waveguide ports; a robotic arm; the robotic arm being disposed inside the dark box for fixing the waveguide antenna board to be tested onto the PCBA; a corner reflector, the corner reflector being disposed inside the dark box for reflecting radar signals emitted by the RF chip; a data processing module and a turntable control module, for controlling the turntable, starting the RF chip to emit radar signals, receiving the echo signals from the corner reflector, and completing the radar antenna performance test.

[0023] For ease of understanding, the specific process of the embodiments of the present invention is described below. Please refer to [link / reference]. Figure 1-4 The rapid testing method and system for millimeter-wave waveguide radar antenna performance in this embodiment of the invention includes:

[0024] The rapid testing method and system for millimeter-wave radar waveguide antennas designed in this invention consists of a PCBA integrating a millimeter-wave radar RF chip, a millimeter-wave radar waveguide antenna board under test, a data post-processing unit, a corner reflector, a dark box, and a robotic arm. The PCBA is fixed in the corresponding position on the turntable inside the dark box. A data transmission cable connects the PCBA to a computer to transmit the data acquired by the PCBA to the data post-processing unit. The PCBA's power supply is also connected. The waveguide antenna board under test is fixed to the PCBA using a clamp. The corner reflector is fixed at an appropriate distance from the waveguide antenna board using a corner reflector bracket. The height and horizontal position of the corner reflector are adjusted to align the corner reflector with the geometric center of the waveguide antenna board. Through the turntable control module and the data acquisition and post-processing module, data from each transmit and receive channel of the waveguide antenna board can be easily acquired, allowing for the evaluation of the antenna performance of each single antenna channel. The automated robotic arm facilitates the convenient replacement of the waveguide antenna board, thus enabling convenient and rapid performance testing of the waveguide antenna board.

[0025] The dark box is lined with 77GHz band absorbing material and kept at a constant temperature and dry to meet shielding, absorption, and quiet zone requirements. The distances from both ends of the dark box to the antenna under test and the corner reflector are maintained at appropriate levels (e.g., 0.5m). The distance between the waveguide antenna under test and the corner reflector is greater than the required far-field distance for the waveguide antenna plate. The far-field distance d can be quickly calculated using the following formula.

[0026]

[0027] Where L is the maximum spacing between the antennas on the waveguide antenna plate, and λ is the wavelength of the electromagnetic wave in the corresponding frequency band.

[0028] The turntable can rotate horizontally and in pitch. The turntable speed is adjustable, with a resolution of not less than 0.05° and a repeatability of not less than 0.05°. The turntable's swing arm and clamps do not obstruct the waveguide antenna plate within a horizontal range of ±85° and within a pitch range of ±60°. The turntable has a load-bearing capacity of not less than 15kg. The turntable and the corner reflector are quickly calibrated using laser.

[0029] The PCBA integrates a 77GHz millimeter-wave radar RF chip and has waveguide ports that correspond one-to-one with the waveguide ports of the RF chip. The RF chip is connected to the waveguide antenna board through these waveguide ports. The waveguide ports on the PCBA correspond one-to-one with the waveguide ports on the waveguide antenna board. The PCBA transmits radar signals through the transmitting antenna on the waveguide antenna board connected to it, and receives the echo signals from the corner transmitter through the receiving antenna on the waveguide antenna board connected to it. The received echo signals are processed by the data processing module on the PCBA and then transmitted to the data post-processing unit on the computer for analysis via a data transmission cable. The PCBA can be the same as the PCBA of the radar product to be manufactured, or it can be redesigned as needed.

[0030] like Figure 2 On the waveguide antenna board, protrusions are provided at all waveguide port positions corresponding to each chip. These protrusions are raised to an appropriate height above the perimeter and have a smooth, flat surface. A rectangular slot of appropriate width and depth is provided around each waveguide port position on the protrusion. The width of the rectangular slot and the width of its sidewalls depend on the distance between adjacent waveguide ports. The depth and width of the rectangular slot meet the requirements for suppressing electromagnetic wave propagation in specific frequency bands and for manufacturing requirements. Preferably, the rectangular slot has a depth of 0.78 mm, a width of 0.5 mm, and a sidewall width of 0.4 mm. The width of the sidewalls shared by the rectangular slot and the waveguide port meets manufacturing requirements. The top surfaces of the two sidewalls of the rectangular slot are in the same plane. These rectangular slots prevent electromagnetic wave leakage when the waveguide antenna board and PCBA have gaps due to improper assembly during waveguide antenna board replacement by the robotic arm, ensuring stable signal transmission. Figure 4It is shown that when there is a 0.2mm gap between the waveguide port of the waveguide antenna board and the waveguide port of the PCBA, the transmission loss (S21) deteriorates very little in the 75GHz to 85GHz frequency band, less than 0.1dB.

[0031] As a preferred implementation method, such as Figure 3 On the waveguide antenna board, protrusions are provided at all waveguide port positions corresponding to each chip. These protrusions are raised to an appropriate height above the perimeter and have a smooth and flat surface. On the PCBA, multiple regular polygonal patches with equal side lengths are provided around each waveguide port. The patches are spaced at the same distance from each other. A metallized via is provided at the center of each patch, connecting the patch to the metal base plate located on the second layer of the PCB substrate. These rectangular patches, together with the waveguide port protrusions, form an ideal magnetic wall around each waveguide port, preventing electromagnetic waves from leaking through gaps when there are gaps between the waveguide antenna board and the PCBA during assembly, and ensuring stable transmission of electromagnetic waves between the waveguide antenna board and the PCBA.

[0032] The metal base plate of the second layer of the PCB substrate:

[0033] The first metal layer on the side of the PCBA closest to the waveguide antenna board is designated as the top layer. The patch is placed on the top layer. Below the top layer, immediately adjacent to it, is a PCB dielectric layer, followed by the second metal layer. The metal base plate is placed on the second metal layer. Below the second metal layer are other dielectric layers and signal trace metal layers placed alternately.

[0034] The robotic arm can be precisely controlled by a program to quickly grasp the waveguide antenna board, fix the waveguide antenna board on the corresponding fixture on the turntable, and assemble it well with the PCBA. After the waveguide antenna board is tested, it can be quickly removed from the fixture and placed in a specific position.

[0035] The waveguide antenna board clamp has a positioning function, which can ensure that the waveguide antenna board is precisely aligned with the waveguide port of the PCBA. It also has locking and unlocking functions, which ensure that the waveguide antenna board can be easily pressed and fixed on the PCBA and can be easily removed from the clamp. The waveguide antenna board clamp and the antenna on the waveguide antenna board will not interfere with each other, and will not affect the performance testing of the waveguide antenna's horizontal and elevation within the required FOV range.

[0036] The waveguide antenna plate can be a waveguide antenna composed of two or more layers of metallized plastic structure, or a waveguide antenna composed of a metal sheet and one or more layers of metallized plastic structure, or a waveguide antenna composed of two or more layers of metal structure.

[0037] The data post-processing unit can easily obtain data such as amplitude pattern, phase pattern, and phase difference of each transceiver antenna on the waveguide antenna board by parsing and processing the data received from the PCBA. By comparing these data with pre-set thresholds, it can quickly determine whether there are any abnormalities in the performance of each waveguide antenna on the waveguide antenna board.

[0038] The corner reflector is a target reflector with a specific RCS value in the millimeter-wave radar operating frequency band, such as an RCS of 5 dBsm, or other target reflectors with relatively stable RCS.

[0039] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention 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 the present invention.

Claims

1. A rapid testing method for the performance of millimeter-wave waveguide radar antennas, characterized in that, The testing method includes the following steps: The PCBA (2) is fixed on a turntable inside the dark box (1). The PCBA (2) integrates an RF chip. The robotic arm (5) inside the dark box (1) is used to fix the waveguide antenna board (4) to be tested onto the PCBA (2); the waveguide antenna board (4) is provided with waveguide ports that correspond one-to-one with the waveguide ports of the RF chip, and the RF chip is connected to the waveguide antenna board (4) through the waveguide ports. Set up an angle emitter (6) inside the dark box (1); The radio frequency chip is activated to transmit radar signals; The radar antenna performance test is completed after receiving the echo signal from the corner transmitter.

2. The rapid performance testing method for millimeter-wave waveguide radar antennas according to claim 1, characterized in that, The specific steps for setting up the corner emitter (6) inside the dark box (1) include: Fix the corner reflector (6) in the dark box (1) at an appropriate distance from the waveguide antenna plate (4). Adjust the height and horizontal position of the corner reflector (6) by using the corner reflector bracket (8) so that the corner reflector (6) is aligned with the geometric center of the waveguide antenna plate (4).

3. The rapid performance testing method for millimeter-wave waveguide radar antenna according to claim 1, characterized in that, The dark box (1) is lined with 77GHz frequency absorbing material.

4. The rapid performance testing method for millimeter-wave waveguide radar antennas according to claim 1, characterized in that, The waveguide antenna board (4) is provided with bosses (41) at all waveguide port positions corresponding to each chip. The bosses (41) are raised to an appropriate height above the periphery and have a smooth and flat surface. A rectangular groove (43) with appropriate width and depth is provided at each waveguide port (42) position on the bosses (41). The width of the rectangular groove (43) and the width of its sidewalls depend on the distance between adjacent waveguide ports (42). The depth and width of the rectangular groove (43) meet the requirements for suppressing the propagation of electromagnetic waves in a specific frequency band.

5. The rapid testing method for the performance of a millimeter-wave waveguide radar antenna according to claim 1, characterized in that, Multiple regular polygonal patches (44) with equal side lengths are arranged around each waveguide port (42) on the PCBA (2). The distance between the patches (44) is the same. A metallized via is arranged at the center of the patch (44). The metallized via connects the patch (44) and the metal base plate disposed on the second metal layer of the PCB substrate.

6. A rapid performance testing system for millimeter-wave waveguide radar antennas, characterized in that, The system includes: Black box (1); PCBA (2), the PCBA (2) is fixed in a turntable inside a dark box (1), and the PCBA (2) integrates an RF chip; Waveguide antenna plate (4), the waveguide antenna plate (4) is provided with waveguide ports that correspond one-to-one with the waveguide ports of the radio frequency chip, and the radio frequency chip is connected to the waveguide antenna plate (4) through the waveguide ports; Robotic arm (5); The robotic arm (5) is set inside the dark box (1) and is used to fix the waveguide antenna board (4) to be tested onto the PCBA (2); Corner reflector (6), which is installed inside the dark box (1) and is used to reflect the radar signal emitted by the radio frequency chip; The data processing module and turntable control module are used to control the turntable, start the radio frequency chip to transmit radar signals, receive the echo signal from the corner transmitter (6), and complete the radar antenna performance test.

7. The rapid testing method for the performance of a millimeter-wave waveguide radar antenna according to claim 5, characterized in that, The system also includes a corner reflector bracket (8) for adjusting the height and horizontal position of the corner reflector (6) so that the corner reflector is aligned with the geometric center of the waveguide antenna plate (4).

8. The rapid testing method for the performance of a millimeter-wave waveguide radar antenna according to claim 5, characterized in that, The dark box (1) is lined with 77GHz frequency absorbing material.

9. The rapid testing method for the performance of a millimeter-wave waveguide radar antenna according to claim 5, characterized in that, The waveguide antenna board (4) is provided with bosses (41) at all waveguide port positions corresponding to each chip. The bosses (41) are raised to an appropriate height above the periphery and have a smooth and flat surface. A rectangular groove (43) with appropriate width and depth is provided at each waveguide port (42) position on the bosses (41). The width of the rectangular groove (43) and the width of its sidewalls depend on the distance between adjacent waveguide ports (42). The depth and width of the rectangular groove (43) meet the requirements for suppressing the propagation of electromagnetic waves in a specific frequency band.

10. The rapid testing method for the performance of a millimeter-wave waveguide radar antenna according to claim 5, characterized in that, Multiple regular polygonal patches (44) with equal side lengths are arranged around each waveguide port (42) on the PCBA (2). The distance between the patches (44) is the same. A metallized via is arranged at the center of the patch (44). The metallized via connects the patch (44) and the metal base plate disposed on the second metal layer of the PCB substrate.

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