Investigating the influence of the antennas on UWB system impulse response in indoor environments

UWB applications will primarily be used in indoor environments due to the power constraints given by the FCC in 2002. Therefore, investigating and modeling the indoor propagation of ultra wideband signals is of great interest. It has been shown, how a narrowband ray tracing tool developed at the Institut fur Hochstfrequenztechnik und Elektronik describing indoor wave propagation can be extended to ultra wideband channels, and first simulation results describing the channel impulse response without antenna influence have already been reported. In this paper, antennas are taken into consideration by combining data of measured complex antenna patterns with the extended Ray Tracing method whereas the antennas are typical UWB antennas. The impulse response of the UWB system including antennas is called system impulse response. Since frequency dependent complex pattern information is used, the system impulse response includes the transient response of the antennas in the time domain. After determining the UWB system impulse response, the differences between channel impulse response and system impulse response are investigated. Furthermore, in both cases, a distance estimation between transmitter and receiver is performed to investigate the impact of antennas in UWB localization applications.