Screen Printed Polarization Independent Microwave Absorber for Wideband RCS Reduction

Abstract

Designing and deploying a broadband microwave absorber that provides wide bandwidth radar cross section (RCS) reduction for planar and curved surfaces is challenging. We present a resistive ink-based multilayered wideband absorber using a low-priced FR4 substrate to cope with the challenge. The reflection coefficient response of the structure lies beneath −10 dB reference over the frequency span of 1.3–18.6 GHz for the normally incident electromagnetic waves. The multilayered structure incorporates the entire microwave radar frequency span with a relative fractional bandwidth of 173.86%. Moreover, to examine the applicability of the structure for a nonplanar geometrical surface, we further design the structure on a very thin FR4 substrate that can be bent easily. We performed an RCS analysis of the redesigned structure under monostatic and bistatic conditions. The structure thereby exhibits novelty in terms of wider stealth and electromagnetic compatibility applications and also a good counterbalance among different design attributes comprising thickness, bandwidth, and periodicity, unlike the earlier reported work. The proposed prototypes are fabricated and experimentally validated for planar and curved surfaces, respectively. The experimental results depict a good concurrence with the simulated results.