Radar MMIC modules typically support radar antenna arrays that are realized on PCB; the modules have 2-4 channels for both Tx and Rx separately with independent amplitude and phase control. This enables the use of beam steering without extra phase shifters. However, the steering is normally done electrically in one plane only as the number of channels is limited. In addition, fixed beam arrays are quite typical due to lower complexity. If more steering capabilities are needed, MMIC modules can be cascaded or the complexity of the RF frontend can be increased with the introduction of phase shifters, amplifiers, or beamformers.
Typical frequencies are:
- 24GHz used for long-range detection
- 66GHz used for shorter range but more accurate sensing
- 77GHz used for accurate automotive radars
In addition to the above, 6.5 to 8GHz UWB radars are an option when sensing through an obstacle is needed at small distances. The lower frequency radars require a larger physical area to achieve similar performance as mmWave radars and this often limits the possibility to have narrow beamwidths for them. However, their penetration capabilities are superior.