Frequency and Bandwidth Dependence of Millimeter Wave Ultra-Wide-Band Channels

If a channel is frequency dependent then Uncorrelated Scattering (US) (a narrow-band assumption) don't hold. This has a significant impact at the considered channel modeling methodology as delay and angular dispersion of waves can no longer be studied independently because the small scale fading of individual multipath components become correlated. In this paper, we investigate the frequency dependence of the 30 GHz millimeter-Wave (mmWave) Ultra-Wide band (UWB) channel. Our indoor small lecture room measured channel results show that both delay and angular spreads vary significantly for different frequencies within a measured UWB channel. This is due to different interactions with objects in the environment due to significant difference in the comparative wavelengths. Therefore, we stress that mmWave-UWB channel modeling methodology must take into account the frequency dependence of channel parameters. In order to support its significance, we have also provided an evidence from mmWave system architecture point of view.