CaCu₃Ti₄O₁₂ particles and MWCNT-filled microwave absorber with improved microwave absorption by FSS incorporation

Multi-walled carbon nanotube (MWCNTs)- and CaCu₃Ti₄O₁₂ (CCTO) particle-filled epoxy microwave absorbing coatings were prepared, and their electromagnetic properties and reflection loss (RL) were investigated in the frequency range 8.2–12.4 GHz. The microstructures of these coatings exhibit a uniform dispersion of MWCNTs and CCTO particles in the matrix. The value and frequency dependency of complex permittivity of such coatings enhanced with increasing MWCNT content. Frequency-selective surface was used to improve their microwave absorption (both the operating bandwidth and minimum RL) without increasing the absorber thickness. Such absorber showed high microwave absorbing performance, and the bandwidth of the RL below −8 dB (more than 84.1 % absorption) can be obtained in the whole X-band with a thickness of 1.5 mm.