Electromagnetic pyramidal cone absorber with improved low frequency design

摘要

A pyramidal cone absorber structure is equated to an effective absorbing layer model having effective permittivity and permeability properties. A Riccati equation, governing the coefficient of reflection of the effective absorbing layer is derived. A computer program solves the Ricatti equation for the coefficient of reflection using initial values of complex permittivity. Iterative solutions are then obtained using increasing values of complex permittivity until no further reduction in the maximum coefficient of reflection over a specified frequency range is obtained, thus indicating optimum performance of the pyramidal cone absorber structure for a given set of cone dimensions. Optimization of the pyramidal cone absorber structure may also be optimized for a fixed set of complex permittivity values by varying the cone length and backing layer dimensions while maintaining the sum of those two dimensions constant.