- The time-domain response of a microstrip quasi-horn antenna was investigated to confirm its suitability for ultra-wideband (UWB) impulse applications. Results show that antenna performance is enhanced using 130, instead of the usual 377, for the antenna aperture. The antenna exhibits good impulse return losses of around 13 and 17dB at the feed-point and aperture, respectively, and high signal fidelity in radiating and receiving UWB signals. Good impulse response with minimum waveform distortion and small reflection together with a planar structure make the microstrip quasi-horn antenna a very good candidate not only for UWB impulse applications but also for direct integration with UWB integrated-circuit transmitters and receivers. 2007 The Institution of Engineering and Technology.