Application of general matching law in design of multilayer absorbing materials

The formula of power reflectivity was developed for multilayer absorbing coatings by general matching law. The constant of general matching law M was defined, and its relationship with power reflectivity R_P, percentage power reflectivity R_bp, thickness d, relative permittivity ε_r and relative permeability μ_r was discussed. It was found that R_bp descends quickly and approaches to zero with the increase of d at M>1; When M<1, R_bP decreases rapidly at the beginning, and oscillates to constant with the increase of d; When M<1 and at the impedance of medium match with aero entirely, the surges of R_bp do not occur. The case of M=1 is the critical state. When 1≤μ_r^′≤4 and d is very small, the value of M has to be larger than 1 if R_P has large dB. It was also found that the enhancement of R_P is not obvious owing to optimized ε_r^″ but optimized μ_r^″, is primary. This is consistent with the panorama analysis method.