Ultra-wideband impulse radar

The requirement for improved performance, in terms of range resolution and target identification, for a range of radar applications, has led to a special category of radar system design. Ultra-wideband radar use a variety of modulation methods such as impulse, FMCW, step frequency, phase coded, etc., but all share the common feature of operation at very high percentage bandwidths, that is, greater than 25% and often 100%. A family tree of the various design approaches is shown. In the case of a radar using an impulse as its excitation, this bandwidth is the instantaneous bandwidth, as opposed to the case of an FM chirp, for example, where the signal is swept through the bandwidth at a rate determined by the radar performance requirements. There are special considerations which apply to ultra-wideband radar systems and in particular impulse radar systems and these fundamentally relate to the fact that whereas the narrowband radar system and hence analysis treats most quantities in terms of power and hence phase information is lost, the wideband radar deals with actual voltages and hence phase information is retained