Ultra-wide band (UWB) technology, as defined by the Federal Communication Commission (FCC) on February 2002, refers to signals or systems that have bandwidth ≥500 MHz or instantaneous fractional bandwidth ≥0.20 . Compared to the conventional narrowband radar that operates with the same centre frequency, UWB radar offers many advantages, including high spatial resolution, for detecting closely-spaced target; and lower probability of interception, for stealth-like military application.
There are many types of UWB waveform. The most obvious and simplest-to-generate UWB waveform is the impulse or short pulse. The pulse width of these impulses is usually sub-nanosecond, which enable a range resolution of 15 cm or less, when it is being transmitted in free space.