This paper illustrates the simulation, implementation and testing of an UWB transmitter based on Step Recovery Diode (SRD). For testing purposes, a square wave generator has been also implemented based on Colpitts oscillator and a clipping circuit that was used to trigger the monocycle pulse generator. The simulated output is a monocycle pulse waveform with 300 ps pulse width and acceptable symmetry in both amplitude and shape. Integrating the UWB transmitter and the Colpitts oscillator, the achieved output from this integration after implementation is a monocycle pulse waveform with 420 ps pulse width and acceptable symmetry in both amplitude and shape.