Radar Absorbing Structures Using Frequency Selective Surfaces: Trends and Perspectives

Abstract

Microwave radar absorbers are widely used in the strategic sector and wireless communication systems to reduce the radar cross-section of a target and electromagnetic interferences, respectively. For airborne stealth platforms, it is desired to have wide bandwidth RAS with minimum thickness and adequate structural rigidity. However, the classical RAS structures are thicker with a narrowband of absorption. So the demand of thin and broadband absorber for a modern stealth platform can be accomplished by designing metallic or resistive frequency selective surfaces (FSSs) based radar absorbing structures (RAS). In view of this, a technological assessment on frequency selective surface (FSS)-based radar absorbing structure are presented in this paper, which includes historical review on radar absorber development, design techniques, physical models, and optimization techniques. Ultra-wideband absorbers with essentially thin structures can be realized by optimizing FSS and dielectric parameters. The genetic algorithm (GA) is identified as one of the effective searching algorithms among several numerical algorithms, which are discussed in detail for single and multi-layered FSS–RAS. The fabrication techniques of resistive FSS by printing the periodic pattern using resistivity-controlled ink is also addressed. For proof-of-the concept, a prototype of cross-dipole FSS based RAS is fabricated and measured.