Toward an effective absorber for damping resonances in shielded enclosures

A procedure for the design of compact and lightweight absorbing material for damping resonances inside shielded enclosure is presented. The proposed absorber is based on the concept of the Jaumann layers and the circuit analog absorbers, since it employs four layers of lossy (artificial) dielectrics separated by two high/low impedance frequency selective surfaces and one resistive sheet. The constitutive parameters of the absorber are optimized by means of the Particle Swarm Optimization in order to maximize its bandwidth and absorption rate in the frequency range centered around 1 GHz, where the first resonances of small commercial enclosures take place.