Terrain backscatter measurements at 40 to 90 GHz

Experimental measurements were made under controlled laboratory conditions to determine terrain backscatter in the 40- to 90-GHz frequency range. Terrain samples in a dry and wet condition included asphalt, concrete, gravel, wood, sod, and tall weeds. Smooth and rough water were also included. The
\bar{\sigma}_{0}
was established for angles of incidence from normal to
45\deg
with the assumption that
\bar{sigma}_{0}
was frequency independent.