Low-frequency representation of radio-frequency absorbers

The low-frequency behavior of RF absorbers and absorber-lined chambers (ALC) is of considerable interest and has received a corresponding amount of attention in the EMC community. We present a simple model to characterize the behavior of radio-frequency absorbers at low frequency. The absorber is represented by a flat, homogeneous, isotropic slab of lossy material, with effective constitutive parameters. These parameters are determined by a fit to measured data. Excellent fits are obtained in the two applications considered. The model is intended for use in the characterization of absorber-lined chambers at low frequency. It could also be used to predict the low-frequency performance of partially loaded shielded enclosures.