Dear Texas Instruments Support Team,
We are reaching out to investigate an issue we are struggling with with our movement detection product that is based on the Texas Instruments IWR6843 chip. Despite initially functioning as expected, we have observed a concerning trend where these radar units begin to exhibit performance anomalies after a period of normal operation exceeding one month.
The core of the issue lies in the reporting of random Doppler points within the radar's field of view, which appear despite the absence of any movement. This anomaly has not affected all our deployed radars units (yet?), but we are receiving an increasing number of similar reports highlighting this issue from our customers.
Our technical team has conducted an internal investigation into potential causes, confirming that the reference 40 MHz clock maintains stable and that there is no measurable noise in the radar's power supply. At the same time there is an impression that the malfunction may be tied to the temperature. Faulty radars operate without issue while being (initially) cold, but after warming up — within a span ranging from thirty minutes to two hours — they begin to erroneously register these phantom Doppler points.
The radar's plastic housing maintains a 1.5 mm air gap from the chip to the wall and has a wall thickness of 1.5 mm, composed of an ABS and polycarbonate plastic blend. The distance from the radar's patch-antenna to the housing wall varies between approximately 1.5 to 3 mm. We are concerned that the housing walls might be influencing the antenna's tuning or causing reflections that contribute to the observed issue (?).
Our observation indicates that once a radar unit begins to malfunction in this manner, the issue persists indefinitely, suggesting a permanent degradation in performance. This pattern raises questions about whether thermal conditions could be contributing to a long-term degradation of the silicon, or if the Doppler point anomaly is a known issue that can be fixed.
Given the critical nature of this problem and its impact on our product reliability and customer satisfaction, we are eager to receive your expert analysis and recommendations on how to address this situation.
We value our partnership with Texas Instruments and are hopeful for your support in resolving this challenge. Your prompt response and any technical assistance you can provide would be greatly appreciated.
Thank you for your attention and cooperation.
Best regards,
Dmitry Tarnyagin
