Antenna Effects in Ultra Wideband Impulse Radio Transmission

An ultra wideband impulse radio (UWB-IR) system can be extremely distorted through a channel even for free-space transmission because of antenna dispersion. This highly degrades the link budget performance. Therefore, the understand of antenna characteristics, which effects on waveform distortion, is necessary. This paper studies the waveform distortion due to antenna on free space transmission in UWB-IR system. The link budget evaluation formula attended from conventional Friis’ transmission formula that takes into account the transmitted waveform, its distortion due to the antennas, the channel and the correlation receiver is proposed. This model is based on the Friis’ transmission formula, adapted to the UWB-IR transmission system, in the sense that we derive the equivalent frequency transfer function of UWB-IR system [1]. Since the antennas are significant pulse-shaping filters in UWB-IR system, the broadband antennas are experimentally examined, especially focused on the effect of the received signal and the isotropic template waveforms. This scheme provides some useful physical insights and optimized design procedure with clear and accessible description of the UWB-IR link budget comprised of practical antennas.