Accession Number : AD0288258

Title :   ABSORPTION AND TRANSMISSION OF ELECTROMAGNETIC WAVES. PHASE L. RESONANCE ABSORBERS WITH ABSORBING STRUCTURES IN OR BEHIND A METAL PLATE

Descriptive Note : Final rept.,

Corporate Author : GOETTINGEN UNIV (WEST GERMANY)

Personal Author(s) : LUHMANN,S.

Report Date : 30 SEP 1962

Pagination or Media Count : 61

Abstract : A number of resonance absorbers for electromagnetic waves are described, which serve for the reflectionless coating of a metal wall. The absorbers are characterized by the fact that the absorbing structure is placed behind the metal wall to be protected. Coupling of the incident wave to the absorbing structure is made through small openings in the metal plate. Rectangular, triangular and circular ring slots were used as coupling holes. With a wedge absorber behind the metal plate the reflection coefficient r was below 0.1 within a frequency interval with a relative bandwidth of about 10%. Absorbing strip-line components were developed in order to achieve a thin absorbing structure and to compensate the frequency dependence of the impedance of the coupling holes. With these components an operating range r < 0.1 with a relative bandwidth of about 6% was attained. The reflection coefficient was measured in the frequency range 8 to 14 kmcps. Its dependence on the number of coupling holes per unit area and on various parameters of the absorber elements was investigated. (Author)

Descriptors :   *ELECTROMAGNETIC RADIATION, *MAGNETIC MATERIALS, ABSORPTION, ATTENUATION, BROADBAND, CRYSTAL LATTICES, CRYSTAL STRUCTURE, ELECTRICAL IMPEDANCE, MICROWAVE EQUIPMENT, POLARIZATION, SCATTERING, WAVE PROPAGATION, WAVEGUIDES

Distribution Statement : APPROVED FOR PUBLIC RELEASE