A new ultra-wideband antenna with enhanced, nearly constant gain is presented. This quasi-planar antenna is composed of a CPW-fed printed monopole and a short horn, both made out of a single substrate. The measurements demonstrate an almost at peak gain of 5.5 dBi ± 0.7 dB from 2.5 GHz to 15 GHz with the average gain difference in XZ plane is roughly 2 dB up to 8 GHz, which further rise to 6 dB at 10 GHz. The antenna also has a nearly linear phase response in this band. Well tested performance both in frequency and time domains, along with broad azimuth pattern, results in minimal ringing of a radiated pulse. The new antenna is suitable for establishing good line of sight link for UWB transmission and other broadband applications.