Abstract: The target signal of ultra-wideband radio fuze is always submerged in the noise due to the signal radiation of ultra-wideband, surface scattering and target signal frequency of ultra-wideband radio fuze. In order to get the echo signal of ultra-wideband radio fuze, the target signal mathematical expressions of ultra-wideband radio fuze are derived by starting from the diffuse reflection characteristics and multipath effects of ultra-wideband signal. The target signal of ultra-wideband radio fuze is simulated with the help of time domain analysis and Matlab. The simulation results show that the time for scattered signal returning to the antenna is different because of the distance from fuze antenna to the antenna beam is different, resulting in broadening effect. The broadening effect is more obvious with the increase in height；the amplitude of ultra-wideband radio fuze echo signal decreases with the increase in height. The correctness of the model is verified by comparing with the measured waveform.

Key words: ordnance science and technology, ultra-wideband fuze, ultra-wideband antenna, echo signal, time domain analysis, broadening effect