UWB Moves up to mmWaves: A channel modeling perspective

UWB has been on the scene for about two decades. Results of extensive tests and measurements, and experience acquired from the design and operation of commercial products, all concurred to depict UWB as a very promising technology in many context and applications, thanks to its intrinsic characteristics. Now, wireless communications are colonizing higher frequencies and the UWB paradigm is a valid candidate for a transmission technology even there. Since many attractive features of UWB are related to its propagation characteristics, this paper provides a synopsis of the behavior of UWB signals on channels at different frequencies, from very low frequencies, below 1 GHz, through the 3.1-10.6 GHz band, and up to the 60 GHz. Finally, a generalized expression is proposed for the channel impulse response over this huge frequency span, accounting for all phenomena and behaviors observed through a variety of channel measurement campaigns at different frequencies and in different environments.