An investigation into the scattering and radiation characteristic of RF-absorbers

The attenuation and radiation characteristics of a pyramidal absorber are studied, both analytically and experimentally, including bulk-parameter data for commercially available, measured samples. Absorber attenuation is modeled as a plane wave incident on a layered medium with a varying complex permittivity. Attenuation experiments performed in a TEM cell confirm the validity of this approach. The antenna behavior of the pyramidal absorber is also considered, treating it as a monopole antenna. The input impedance and radiation are both modeled and measured. It is shown that the absorber can radiate significantly, which can affect its usefulness, depending on the intended application. Special consideration has been given to the low-frequency performance (<100 MHz) of absorbers.<>