Compared to UWB SRR with several GHz of bandwidth, narrowband radar can only use a maximum bandwidth of 250 MHz from 24.00 GHz to 24.25 GHz. This ISM band is allocated internationally for industrial, scientific and medical applications. In most countries over the world similar allocations are generally allowed for SRD (short range device), including motion detection radars in Europe (see Table 4).

Some national restrictions either limit the bandwidth or the emitted power of SRDs operating in the ISM band. In general, the allowed emission power for narrowband radars is much higher compared to that of their UWB counterparts.

Because of the limited bandwidth, the local resolution is also limited. Therefore narrow band sensors are limited in applications.