DESIGN OF BROAD-BAND RADAR-ABSORBING MATERIALS FOR LARGE ANGLES OF INCIDENCE

A numerical technique, called (modified) Powell method, is used to des ign radar-absorbing materials (RAM's), made up of several dielectric l ayers, usually on top of a conducting (ground) plane. The absorption o f RF energy is mostly done in the last layer. The others are used to m atch the wave impedance of the RAM to that of the incidence media for the desired angles of incidence, frequencies, and polarizations. The t echnique is very flexible, allowing the design of RAM's tailored for s pecific applications or general use. One important example is the desi gn of RAM's that can maintain a minimum absorption rate from normal to almost grazing incidence, over a specified frequency bandwidth.