Percolation‐Triggered Kilohertz ε′‐ Negative Response by 3D Copper Network

A 3D percolated Cu network structure in the CaCu ₃ Ti ₄ O ₁₂ (CCTO) matrix by using the classic conductor/insulator composite system is constructed. Typical electrical percolation behavior occurs when the Cu content is between 30 and 40 wt%, and it is manifested as a sudden change from hopping conductivity to metalloid conductivity. The evolution of percolation structure has triggered a transformation of the dominant dielectric response mechanism within metacomposites from interface polarization to plasmonic oscillation. The percolated Cu/CCTO metacomposites thus achieved a ε′ ‐ negative response of the 10 ⁶ orders in the kilohertz frequency band, with its plasmonic oscillation frequency and damping factor at the GHz and MHz orders, respectively. By performing equivalent circuit analysis, the intrinsic correlation is clarified between ε′ ‐ negative response and inductance characteristics as well as the phase relationship transformation. Finally, the radar cross‐sectional characteristics of positive‐negative dielectric media is analyzed by using electromagnetic simulation technology.