Radar absorbers: better by design

Abstract

The radar cross section of a structure can be controlled by shaping it and either covering it with radar absorbing materials (RAM) or manufacturing the structure from absorbent engineering materials. A radar absorbing layer can be designed from a knowledge of the complex permeabilities and permittivities of the constituent materials and their frequency dependence. Constrained (in waveguide), and free field (open resonator) techniques for measuring these properties are described and results presented for a ferromagnetic material at microwave frequencies. A computer design methodology is discussed and results are compared with practical absorbers.