Realization of Thin and Broadband Magnetic Radar Absorption Materials With the Help of Resistor FSS

In this letter, a kind of composite radar absorption material consisting of gradient and spiral square resistor frequency selective surface (FSS) and magnetic sheets is designed by HFSS. The use of resistor FSS makes a significant increase of operating bandwidth compared to single magnetic radar absorption materials (mRAMs). Under the condition of normal incident electromagnetic wave, it has remarkable absorptive performance with the reflectivity below -10 dB with a thin thickness of 2 mm in the range of 6-18 GHz. In addition, the composite mRAMs exhibits high angular stability when the incident angle ranges from 0 ° to 30 °. In order to illustrate the importance of resistors, a comparative experiment of structure with nonresistor FSS is made. Experimental results are compared to numerical simulations. They are in agreement with each other.