Effect of delamination on the electromagnetic wave absorbing performance of radar absorbing structures

The purpose of this study is to understand a correlation between interlaminar delamination and radar absorbing performance of composite radar absorbing structures (RAS). Many researches have been conducted on composite RAS and composite delamination. No study, however, has dealt with the delamination effect on the radar absorbing performance of RAS so far. In this study, a multi-layer Dallenbach radar absorber with glass/epoxy and glass/epoxy-Multiwall Carbon Nanotubes (MWCNT) was designed. Based on the design, test specimens were fabricated and the ‘split specimen’ test method was introduced. This novel test method, for measuring the electromagnetic wave reflection and absorption, enabled quantitative analysis of the delamination effect by implementing delamination with various thicknesses and locations on the same specimen. The reflection loss of the specimen for normal incident EM waves in the X-band was measured. The measurement and analysis results verified that the changes in the thickness-wise location and thickness of the delamination altered the magnitude as well as the resonance frequency of the reflection loss.