Frequency Dependency of Delay Spread and Path Loss in Indoor Ultra-Wideband Channels

This paper depicts results from indoor ultra-wideband (UWB) measurements. Analysis focuses on frequency dependency of r.m.s. delay spread and path loss in the frequency range of 1 ... 11 GHz. The indoor channel measurements were made by a network analyzer with a 10 GHz bandwidth. Exactly the same environment was measured with 500 MHz bandwidth at 1.25, 2.25, 5.25, 5.75, and 10.75 GHz centre frequencies. Naturally the average received signal level decreases with increasing frequency. Nevertheless, it is noticed that delay spread and thus the coherence bandwidth depends only slightly - or negligibly - on the centre frequency. However the regression line of delay spread vs. frequency seems to be declining. Critical parameter for the delay spread analysis is the threshold, above which the signal energy is being analyzed.