Influence of UWB-antennas on UWB-channel-measurements in a city-liner coach

Since the introduction of UWB-applications a lot of UWB antennas of different type, shape and size have been discussed. Their performance usually is described in terms of efficiency, gain and match at the feeding point. Additionally, according to their shape, their directional characteristics range from quasi omni directional to very directive. However, one can hardly find information about how antenna parameters affect an actual UWB-channel. This paper describes a measurement campaign in a large coach with 48 seats. UWB-transfer-functions from 3 GHz to 8 GHz are measured with a network analyzer with four different antenna types at several emitting and receiving positions. UWB channel setups with the respective antenna types are characterized in terms of its impulse response and path loss. Summarizing these results it can be stated that antennas with a reasonable match at the feeding point show a similar performance. Additionally, scenarios are discussed, where a high directive antenna is compared with an omni directional one.