The paper presents the procedures and results of experimental researches of radioabsorbing structures on flat metal substrates and three-sector sides of one of the eight trihedral angular reflectors forming an octahedron layout. The results were obtained in the time domain by a measuring antennas parameters unit with an automatic calibration of the reflection coefficient or on the reverse side of the substrate or by one of five trihedral angular reflectors with uncovered faces while rotating the researched structures on a rotary support.