A practical method of measuring scattering characteristics of a pyramidal absorber

A free-space, standing-wave technique at oblique incidence is studied as a method of measuring the scattering characteristics of a pyramidal or wedge-shaped absorber. Using this method, the standing-wave ratio in front of the sample from waves with electric fields of equal amplitude are scattered in three different directions, and their scattering angles are easily measured over a wide range of frequencies and angles of incidence. No special measuring apparatus or complicated procedures are required with this method. It is found that the standing-wave ratio around 1.1 (magnitude of the scattering coefficient=0.04762) is less than ±20% in terms of scattering coefficient for incident angles ranging from 0° to 80°. The error in the scattering angle is less than 4° for the 0° scattered wave and less than ±3° for all other scattering angles