Gen1 (AWR1243, AWR1843, AWR1642, and AWR1443) and Gen2 (AWR2243) radar devices include self-calibrations to mitigate process and temperature effects on analog performance. The calibrations include RF INIT (i.e., boot time) calibrations to mitigate manufacturing process variation effects, and Run Time calibrations to mitigate temperature effects. These calibrations mostly involve optimizing the RF register settings for TX, RX, and LO-based on the temperature read by the built-in temperature sensors. In simple single-chip usage context, these self-calibrations achieve the purpose of analog performance stabilization without compromising on inter-channel imbalances due to inherent channel matching within each device.

Maintaining inter-channel matching in multi-device cascaded sensors is more challenging due to manufacturing process mismatches across devices and independence of the self-calibration procedures running in the multiple devices. This note describes recommendations to improve a cascade system’s coherence across time and temperature and involves more control of AWR devices by the host processor on the sensor. Further, the recommended procedures may also be used in advanced single chip applications which desire stability of the radar return signal’s absolute phases across radar frames, devoid of abrupt jumps.

Further, the recommendations in this note also address the topic of avoiding corruption of the self-calibration results when the device operates in interference-prone environments. Note that the same is also briefly explained in Self-Calibration in TI’s mmWave Radar Devices (SPRACF4), applicable in single chip usages. Finally, another important topic addressed in this note is TX phase shifters (AWR1843 and AWR2243). Their accuracies can be improved with calibrations at customer factory as well as in field, and this note describes relevant recommendations.