We present a novel injection locking frequency generation scheme for UWB systems. In the MBOA-UWB specification, the critical constraint on the frequency synthesizer is the band switching time (< 9.5 ns). In this paper we derive analytical expressions for the transient behavior of injection locked oscillators (ILO) and describe the design constraints on frequency settling of ILOs. We show that they are capable of UWB compliant fast frequency hopping. ILO based frequency synthesizers have a number of advantages over traditional fast hopping LO generation techniques. In particular, it eliminates the need for multiple PLLs and single-sideband (SSB) mixers reducing power consumption and eliminating parasitic spurs.