Wideband Characterization of Backscatter Channels

Inhalt:
The wireless channel of backscatter radio systems is a two-way pinhole channel, created by the concatenation of two standard wireless channels. Pinhole channels cause higher attenuation and deeper fades than common wireless channels. Passive ultra-high frequency radio-frequency identification (UHF RFID) is such a backscatter radio system, with the backscattering tag acting as pinhole. While the effects of this type of channel are well-known in terms of fading statistics, the impact of the pinhole channel on wideband parameters is unknown. We present a method to calculate wideband backscatter channel parameters from the parameters of the constituent channels to and from the pinhole, with a focus on characteristics that are vital for narrowband and wideband ranging. The approximations are verified by simulations and by measurements in a UHF RFID warehouse portal.