A Waffle Structured Composite for Rcs Reduction Via Absorption and Scattering Mechanisms

Abstract

A radar absorbing material named waffle structured composite (WSC) was proposed based on the periodic structure element formed in double-sided knitting process. The unique pattern shaped by the knitted loops achieved the collaborative mechanisms of absorption and scattering. The radar cross section (RCS) below -10dB was achieved ranging from 12 to 18 GHz for WSC in course direction, and RCS reduction peak can reach to -30dB. Through the S-parameter analysis and simulation, the RCS reduction mechanism was revealed for WSC in both wale and course direction. It was found that the low-frequency RCS reduction in the wale direction was mainly dominated by the absorption mechanism, and the high-frequency RCS reduction in the course direction was led by the scattering mechanism. Furthermore, to further explore the scattering and absorption mechanism, phase difference, dielectric loss and magnetic loss were investigated in details. It was verified that the absorption of WSC is mainly originated from dielectric loss with slight magnetic loss, and Debye relaxation plays the important role in dielectric loss. The WSC proposed in this paper is equipped with characteristics of good RCS reduction and continuous large-scale manufacture, which is promising in practical engineering application of radar stealth.

Keywords: Radar absorbing material, knitted structure, Scattering mechanism, Absorption mechanism