Characterisation of microwave four-parameter materials and its application in wideband radar absorber design

A new free-space measurement technique for the characterisation of four-parameter microwave materials is presented. The method employed offers the advantage of evaluating the specimen under conditions close to those of the operational environment. In addition, it does not require reconfiguration of the system during the measurement process. The procedure is shown to be tolerant of measurement errors and provides good accuracy in the derived material parameters. The technique is validated by the design and evaluation of a practical absorber over a 6:1 frequency range