  With the relatively recent realization that millimeter wave frequencies are
viable for mobile communications, extensive measurements and research have been
conducted on frequencies from 0.5 to 100 GHz, and several global wireless
standard bodies have proposed channel models for frequencies below 100 GHz.
Presently, little is known about the radio channel above 100 GHz where there
are much wider unused bandwidth slots available. This paper summarizes wireless
communication research and activities above 100 GHz, overviews the results of
previously published propagation measurements at D-band (110-170 GHz), provides
the design of a 140 GHz wideband channel sounder system, and proposes indoor
wideband propagation measurements and penetration measurements for common
materials at 140 GHz which were not previously investigated.
