A Quadrupole Tensor Analysis Approach to Design a Broadband Absorber

Abstract

The purpose of this paper is to design a broadband and very thin absorber with periodic structure using magneto-dielectric particles. A theoretical method has been developed for the analysis of periodic structures. This method has the ability to compute the field, reflection, transmission, and absorption for different number of layers and particles with different shapes and dimensions. In this paper, in addition to electric and magnetic dipole moments, quadrupole equivalences of particles are considered as well. This will help the analytical approach to calculate the fields more accurately. It is shown how these changes, will help to design a broadband absorber in microwave regime. Then a step-by-step method for design an absorber is presented based on this theoretical method that is called planar analysis method. In addition, due to the properties of magneto-dielectric materials that can have electrical and magnetic effects together and often have high losses; we can have broadband absorbers using these materials. In this paper, an absorber based on rectangular cube particles composing magneto-dielectric material is designed. The simulation results show that the absorber has 104% bandwidth for absorption above 90%. The thickness of this absorber with respect to center of absorption bandwidth is λ/12.

Keywords

• Discrete dipole approximation (DDA)
• interaction field
• polarizability
• quadrupole tensor