Abstract: An ultrawideband (UWB) time-reversal (TR) imaging method based on frequency domain sampling and time domain synchronism is presented. A pulse signal from a single transmitter is sent to the imaging domain, and the scattering fields are received by each element of the time-reversal mirror (TRM). A multistatic data matrix (MDM) at each element is formed by casting the fine and coarse frequency domain samples of the scattering information into a matrix form, called findividual requency-frequency MDM (FF-MDM). A full FF-MDM is constructed by stacking all the individual FF-MDM together, and the singular value decomposition (SVD) is applied to the full FF-MDM. The left singular vectors provide the spatial information for focusing the embedded targets or scatter centers, and different left singular vectors correspond to different targets. Each left singular vector at each TRM element is converted into the retransmitting pulse signal, and these retransmitted signals from each TRM element will achieve their waveform maximum values synchronically at the corresponding target position but non-synchronically at other positions. As a result, by defining the multiplication of these retransmitted signals as the final imaging function, good resolutions in both down-range and cross-range directions can be obtained.