HF path integrity monitoring method for radar sensor, radar sensor, and computer program therefor

Abstract

The invention relates to a method for monitoring the integrity of a high-frequency (HF) path in a radar sensor, the method comprising: measuring an isolation between different radar channels in order to identify an influence on an electromagnetic connection which indicates a mounting connection fault, and / or analyzing a noise level in the radar signal spectrum in order to identify an increase in a spectral noise which indicates a mounting connection fault.

Description

[0001] Description

[0002] RF path integrity monitoring method for radar sensor, radar sensor and computer program therefor

[0003] The present invention relates to a monitoring method and a monitoring device for monitoring the integrity of a radio frequency (RF) path in radar sensors. The method and the device address the problem of faults in assembly connections between elements of a radar antenna, such as the connection of a waveguide segment attached to the antenna circuit board (PCB) used in radar antennas. Such faults can impair the radar's ability to accurately determine angles due to misalignment or separation of the antenna components. The invention utilizes measurements of the isolation between radar channels and / or the spectral noise to detect and respond to these faults.

[0004] State of the art

[0005] Radar sensors are crucial components in numerous applications, ranging from vehicle safety systems to weather monitoring and airspace surveillance.

[0006] A typical radar sensor consists of an antenna array, waveguide channels, and a circuit board. The antenna array comprises several elements that transmit and receive high-frequency (HF) signals. These elements are often aligned to produce directional beam patterns that can be adjusted to cover various angles. A key element in some applications of these radar sensors are the waveguides, which are bidirectional structures for guiding electromagnetic (EM) waves: They guide EM waves from the antenna to the processing unit and from the processing unit back to the antenna. During the transmission phase, the waveguide channels carry the RF signals generated by the radar's transceiver to the antenna array. These signals are then radiated into the environment as EM waves.During the receiving phase, the antenna group captures EM waves reflected by objects, and these waves are then guided back to the radar's transmit receiver through the waveguide channels and processed.

[0007] Waveguides are typically made of metals or metal-coated plastics due to their effective electromagnetic properties. The integrity of these materials and their assembly is of paramount importance for sensor performance. The mounting connections or terminals of the waveguide components are particularly critical. These connections can be secured by soldering, adhesive bonding, or mechanical fastening, each of which presents its own challenges. Soldering offers a permanent bond but can fail under thermal stress; adhesive bonding offers versatility but can weaken under fluctuating environmental conditions; and mechanical fastening, while allowing for easy assembly, requires precise execution to avoid misalignment.

[0008] The disassembly or deterioration of these mounting connections can go unnoticed and is a significant problem for radar sensors. If a mounting connection fails—whether between the antenna halves or between the antenna and the circuit board—it can lead to electromagnetic leakage, impairing the signal's efficiency and directionality. Further complications include signal reflections or scattering due to misalignment or gaps at the connection point, as well as unwanted coupling effects resulting from the proximity of transmit and receive channels when the insulation is compromised. These defects in the waveguide mounting connections can significantly impair the radar sensor's functionality. In automotive applications, for example, a faulty waveguide connection can lead to inaccurate object detection.Given the high importance of these applications, effective monitoring of the waveguide connections and the resulting RF path of the radar sensor is of utmost importance for maintaining the accuracy and operation of radar-based functions.

[0009] Disclosure of the invention

[0010] The present invention relates to an RF path integrity monitoring system for radar sensors, which serves to correct potential errors in the mounting connection points used in the assembly of radar antennas, in particular when joining two antenna halves or to keep the waveguide on the circuit board in a correct position.

[0011] One solution for carrying out this monitoring may be to measure or quantify the effects of the link points / link fault by checking the isolation between the radar channels and / or the evolution of interference noise in the radar spectrum.

[0012] The proposed approach therefore includes a method for monitoring the isolation between different radar channels at the integrated circuit (IC) level. By measuring this isolation, the system can detect any interference with or deterioration of the electromagnetic connection (coupling) in the waveguides, indicating possible assembly connection errors.

[0013] Additionally or alternatively, the proposed approach includes a method for analyzing the noise in the radar signal spectrum. An increase in spectral noise may indicate electromagnetic radiation leakage into free space due to a damaged mounting connection. The present invention comprises an RF path integrity monitoring method for radar sensors according to claims 1 to 8, a radar sensor according to claim 9, and a computer program according to claim 10.

[0014] Preferred further training courses are the subject of the subclaims.

[0015] Advantages of the invention

[0016] The present invention offers an efficient solution for improving the reliability of radar sensors by introducing monitoring functions to monitor the failure risk at the radar connection level, e.g., the connection for mounting waveguides and their correct positioning. One of the advantages of this approach is the ability to detect and diagnose potential problems in real time and at an early stage, thereby significantly reducing the risk of serious system failures that could lead to inaccuracies in critical applications such as automotive safety.

[0017] By measuring the isolation between radar channels and / or analyzing the background noise within the radar signal spectrum, the system can proactively detect signs of deterioration or damage caused by faulty mounting connections. This early detection enables preventative maintenance and rapid corrective action, minimizing downtime and preventing or reducing the occurrence of more serious problems that could impact operational efficiency.

[0018] According to the invention, in the method for monitoring the integrity of a radio frequency (RF) path in a radar sensor, according to claim 1, the method: measures isolation between different radar channels to detect interference with an electromagnetic connection or coupling that indicates an assembly connection fault, and / or analyzes a noise level in the radar signal spectrum to detect an increase in spectral noise that indicates an assembly connection fault.

[0019] According to a preferred embodiment, the method includes measuring the insulation and the insulation measurements are expressed in decibels (dB) and a decrease in the dB value indicates reduced electromagnetic coupling.

[0020] According to a preferred embodiment, the method comprises measuring the insulation, wherein the method further comprises a step of comparing the insulation measurements with a predefined threshold to determine whether there is any deterioration indicating potential failures.

[0021] According to a preferred embodiment of the method, the predefined threshold is determined based on operational requirements and typical signal levels of the radar sensor.

[0022] According to a preferred embodiment of the method, the predefined threshold value is stored in a memory element of the radar sensor and retrieved to perform the comparison.

[0023] According to a preferred embodiment, the method further includes reporting an error if the insulation measurement values ​​fall below the predefined threshold.

[0024] According to a preferred embodiment, the method comprises analyzing interference noise in the radar signal spectrum, wherein the method includes detecting an increase in spectral interference noise in the complex radar signal spectra that indicates an assembly connection fault.

[0025] According to a preferred embodiment, the method further includes reporting an error when a measured noise level reaches a predefined threshold from the normal noise level. The invention provides a radar sensor with means for detecting isolation between different radar channels and for carrying out the inventive method, and / or with means for detecting a noise level in the radar signal spectrum and for carrying out the inventive method.

[0026] According to the invention, a computer program product is provided with instructions which, when the program is executed by a processing element of a radar sensor, cause the processing element to carry out the inventive method.

[0027] Brief description of the drawings

[0028] Fig. 1 is a sectional view of a radar system 100.

[0029] Fig. 2 shows the situation of a radar system in the same sectional view as Fig. 1, but with a crack and a separation / displacement of the waveguide.

[0030] Fig. 3 is a side view where the waveguides are attached to the circuit board.

[0031] Fig. 4 is a diagram illustrating the coupling for an example with 16 channels, with the coupling value in dB on the y-axis and the measurement ID on the x-axis.

[0032] Fig. 5 is a table of values ​​that corresponds to the diagram in Fig. 4.

[0033] Fig. 6 shows a noise vector in dB against the k-bin for a connection between an antenna and a printed circuit board.

[0034] Fig. 7 shows a noise vector in dB compared to the k-bin for a connection between an upper and a lower antenna.

[0035] Detailed description of the invention The following is a detailed description of embodiments of the present invention with reference to the accompanying drawings.

[0036] Fig. 1 is a sectional view of a radar system 100. This radar system can comprise a system on a chip 101 or a microelectronic component, a substrate or a printed circuit board 102, a waveguide component 103 and an antenna group.

[0037] The Chip 101, or microelectronic component, is a layer that includes the integrated circuits (ICs) that process the incoming and outgoing signals. These components are responsible for tasks such as signal modulation and demodulation, signal processing, and converting the radar measurements into usable data.

[0038] The printed circuit board 102 carries and connects the electronic components and antenna elements. It is located near the lower part of the waveguide structures and is designed to integrate seamlessly into the overall RF path. Various electronic circuits, including amplifiers, filters, and processors, can also be housed on the circuit board.

[0039] The waveguide component 103 is attached to or integrated into the antenna array. Its purpose is to guide electromagnetic waves to and from the antenna elements. In many designs, it may comprise specially shaped channels or tubes that precisely guide the RF energy.

[0040] The antenna array can comprise several antenna elements made of metal or other conductive materials, arranged in specific patterns (e.g., linear, circular) to control the beam direction and focus. Antenna array 104 is central to transmitting and receiving electromagnetic waves.

[0041] The present embodiment relates to a mounting connection or transition 104 between the waveguide component 103 and the printed circuit board 102. However, those skilled in the art understand that the proposed monitoring solution is also applicable to other mounting connections or mechanical connections. In the present illustrative and non-limiting embodiment, the mounting connection can be an adhesive interface that holds the waveguide in position on the printed circuit board.

[0042] Fig. 2 shows the situation of a radar system in the same sectional view as Fig. 1, but with a crack and a separation / displacement of the waveguide. In particular, it can be seen in Fig. 2 that the waveguide has detached from the connection point or the adhesive interface 104 (i.e., is displaced in the x-direction) and the waveguide 103 is also displaced to the left (direction y). Those skilled in the art know that this displacement can also occur in the z-direction or in the x-direction, or in two of these directions, or even in all three directions x, y, and z.

[0043] In so-called Gen6 and Gen7 radar sensors for the automotive industry, the antenna is (usually) attached to the circuit board using adhesive bonds to keep it in the correct position. Gen7 sensors use an additional adhesive bond to connect the two halves (top and bottom) of the antenna. As mentioned earlier, these adhesive bonds can fail over time, compromising the integrity of the RF path in the radar sensors. While such partial failure of these mounting bonds may not completely break the connection, it can still lead to significant problems, such as incorrect angle calculations.

[0044] If these adhesive bonds deteriorate, they can no longer contain the electromagnetic radiation within the waveguide channels, allowing it to escape into free space. This leakage can lead to interference, as the radiation from the transmitting part of the IC can couple into the receiving part due to the proximity of the channels in the radar system. This effect can manifest as a measurable reduction in the isolation between the channels, directly impacting the sensor's accuracy. Furthermore, this coupling and the resulting structural integrity issues can also lead to an increase in the radar's spectral noise, which is another indicator of impaired sensor performance. These phenomena highlight the critical importance of monitoring the integrity of the adhesive bonds to ensure the radar's reliable operation.

[0045] Fig. 3 is a side view showing the waveguides attached to the circuit board. In this illustrative and non-limiting case, a waveguide 103 is positioned on the circuit board 102 in the zy plane, as shown in Fig. 3. If a crack and separation occur as mentioned above, the waveguide 103 can move, particularly in the y and z directions (the so-called lateral movements of the waveguides), but also in the x direction. As mentioned earlier, in such a case a change in the insulation between the radar channels can be observed, which may indicate such a failure.

[0046] In other words, in one embodiment of the present invention, isolation monitoring between the channels in the radar sensor functions is performed by evaluating how well electromagnetic signals are confined to their assigned paths. Isolation in this context refers to the degree to which electromagnetic signals in different channels do not interfere with each other. Effective isolation means that the signals transmitted by one part of the antenna array do not significantly affect the signals in other parts, which is crucial for avoiding or reducing crosstalk between transmit and receive channels that could lead to an erroneous interpretation of the radar data.

[0047] To measure isolation, the system sends signals through one channel and measures how much of that signal is detected in another channel. This measurement is typically given in decibels (dB), with a higher dB value indicating better isolation. Good isolation ensures that the power of one transmission channel does not significantly affect the reception quality in adjacent channels. Conversely, the isolation measurement will have a low dB value if a large portion of the signal is detected in other channels. In an advantageous embodiment, the worst-case isolation is monitored across all sensor channels.

[0048] For such isolation, a preset value can be defined as a coupling parameter value, above which the isolation is poor and indicates a problem with the positioning of at least one waveguide.

[0049] Here too, such insulation monitoring is of utmost importance for detecting structural integrity problems, such as faults in the adhesive bonds that hold the antenna components or secure them to the circuit board. Over time, these bonds can deteriorate, leading to misalignment in the waveguide channels and allowing electromagnetic radiation to deviate from its intended path or penetrate another. Such leakage results in reduced insulation between the channels.

[0050] A control element or processing unit of the radar system can continuously monitor the insulation as part of normal operation. If the insulation falls below a predefined threshold—an indication of potential leakage due to adhesive bond failure—the system detects a problem. This threshold can be set based on the application's sensitivity requirements and typical signal levels.

[0051] If the system detects reduced isolation, it can take corrective action, such as notifying maintenance teams, switching to a fail-safe mode that relies on data from unaffected channels, or even temporarily shutting down to prevent faulty data generation.

[0052] It should be noted that the predefined threshold may vary between different radar sensors due to different production tolerances, and calibration may be necessary. In such a case, the initial value can be written to the sensor's memory, and it can be checked regularly whether the value is deteriorating.

[0053] In an exemplary embodiment, the sensor has 16 channels, and a coupling parameter of less than -45 dB indicates a poor situation.

[0054] Fig. 4 is a diagram showing the coupling for this illustrative example with 16 channels, with the coupling value in dB on the y-axis and the measurement ID on the x-axis, where the measured values ​​are approximately between -25dB and -55dB.

[0055] Figure 5 is a table of values ​​corresponding to the diagram in Figure 4 for the illustrative example mentioned above. The columns refer to a measurement ID and then to the displacement in the three directions x, y, and z. Values ​​below -45 dB are considered poor.

[0056] The other approach to detecting such assembly connection errors involves monitoring the noise level of the complex spectra of the radar signal.

[0057] In other words, in one embodiment of the present invention, the noise level in the radar sensor functions is determined by analyzing the spectral noise characteristics of the radar signals. Such monitoring of the noise level provides insights for detecting potential problems with the structural components, such as adhesive bonds in the waveguide assembly.

[0058] In radar systems, noise typically refers to unwanted or interfering signals that can distort or obscure the true radar feedback from targets. This noise can originate from various sources, such as the electronic components themselves (like amplifiers or processors), environmental disturbances, or structural defects within the radar system. In the context of the present invention, an elevated noise level may indicate that the electromagnetic radiation is deviating from its intended path due to compromised waveguide integrity, such as a faulty adhesive bond.

[0059] The proposed monitoring process begins with the radar system continuously measuring background noise across its operating bandwidth. The radar's signal processor or controller can analyze the complex spectra of the received signals to identify and quantify the noise components. Radar systems typically operate within a specific noise threshold to ensure accuracy in object detection and tracking. However, if the structural integrity of the waveguide is compromised, the overall noise level can increase, particularly the spectral noise, which is the random fluctuation of signal power across the frequency spectrum.

[0060] If the background noise level exceeds predefined thresholds, this indicates potential problems. These thresholds can be set based on operational requirements and the typical background noise of the radar system. Exceeding these thresholds can trigger an alarm in the system, prompting further diagnostics or initiating a fail-safe mode to prevent the radar from generating and reacting to erroneous data.

[0061] Another proposed approach is to measure the noise level using a special modulation (which cleans the spectrum of targets and noise signals).

[0062] Figures 6 and 7 illustrate such an application in two examples.

[0063] Fig. 6 shows the noise vector in dB compared to the k-bin, which relates to a frequency range or segment within the spectral analysis for a connection between an antenna and a printed circuit board. It highlights three cases in particular: a small deviation where the noise signal corresponds to a reference signal, a deviation from this reference signal at a waveguide spacing of 0.7 mm, and a larger deviation at a waveguide spacing of 0.9 mm.

[0064] Similarly, Fig. 7 shows the noise vector in dB versus the k-bin for a connection between an antenna top and a

[0065] Antenna underside. It shows in particular two cases: a small deviation where the noise signal corresponds to a reference signal with a distance of less than 0.15 mm, and a larger deviation from this reference signal at distances of more than 0.15 mm.

Claims

Claims 1. Method for monitoring the integrity of a radio frequency (RF) path in a radar sensor, the method comprising: - Measurement of isolation between different radar channels to detect interference with an electromagnetic connection or coupling that indicates an assembly connection fault, and / or - Analysis of a noise level in the radar signal spectrum to detect an increase in spectral noise that indicates an assembly connection fault.

2. Method for monitoring the integrity of a radio frequency (RF) path in a radar sensor according to claim 1, wherein the method comprises measuring the isolation and wherein the isolation measurements are expressed in decibels (dB) and a decrease in the dB value indicates reduced electromagnetic coupling.

3. Method for monitoring the integrity of a radio frequency (RF) path in a radar sensor according to one of claims 1 or 2, wherein the method comprises measuring the insulation and the method further comprises a step of comparing the insulation measurements with a predefined threshold value to determine whether there is any deterioration that indicates potential failures.

4. Method for monitoring the integrity of a radio frequency (RF) path in a radar sensor according to claim 3, wherein the predefined threshold is determined on the basis of operational requirements and typical signal levels of the radar sensor.

5. Method for monitoring the integrity of a radio frequency (RF) path in a radar sensor according to claim 3 or 4, wherein the A predefined threshold value is stored in a memory element of the radar sensor and retrieved to perform the comparison.

6. Method for monitoring the integrity of a radio frequency (RF) path in a radar sensor according to any one of claims 3 to 5, further comprising reporting a fault when the insulation measurements fall below the predefined threshold.

7. Method for monitoring the integrity of a radio frequency (RF) path in a radar sensor according to any one of claims 1 to 6, wherein the method comprises analyzing interference noise in the radar signal spectrum, wherein the method comprises detecting an increase in spectral interference noise in the complex radar signal spectra that indicates an assembly connection fault.

8. Method for monitoring the integrity of a radio frequency (RF) path in a radar sensor according to claim 7, further comprising reporting a fault when a measured noise level reaches a predefined threshold from the normal noise level.

9. Radar sensor with means for detecting isolation between different radar channels and for carrying out the method according to one of claims 1 to 6 and / or with means for detecting a noise level in the radar signal spectrum and for carrying out the method according to one of claims 7 and 8.

10. Computer program product comprising instructions which, when the program is executed by a processing element of a radar sensor, cause the processing element to perform the method according to any one of claims 1 to 8.

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