Description
Frequency-Modulated Continuous-Wave radar transmits a chirp whose instantaneous frequency increases linearly with time; mixing the reflected return with the transmitted signal produces a beat tone whose frequency encodes range. FMCW MIMO radars (TI AWR / IWR series, NXP S32R) dominate the consumer mmWave-sensing literature and produce dense range-Doppler-angle cubes that complement WiFi-based sensing.
When it's used
- Indoor mmWave HAR / crowd counting
- Precise range-Doppler signatures
- Reference modality for evaluating WiFi-CSI sensing
- Vehicle-cabin and gesture sensing
Limitations
- Hardware cost > commodity Wi-Fi
- Limited line-of-sight coverage (mmWave attenuates fast)
- Multipath ghost targets in close-range indoor scenes