Multilayer radar absorbing materials with light weight, strong absorption, and wide absorption bandwidth are urgently demanded the increase of electromagnetic pollution. However, current design methods only simulation operation or optimization strategy not comprehensive. Here, a simulation-optimization approach including numerical calculation is proposed based on interaction between different s...

1 Abstract This paper describes a topology optimization method for structures in electromagnetic materials. The material structures that exhibit special characteristics in terms of the repulsion of electromagnetic waves tend to be configured as periodical composite structures built of two or more materials. Generally termed “metamaterials”, these sometimes have especially unusual or even counte...

Solving aero-acoustic or electromagnetic wave-dominated problems often requires finding accurate infinite domain solutions on a finite computational domain. One way of accomplishing this is to formulate absorbing boundary conditions through the technique of perfectly matched layers (PML). We discuss recent developments of PML methods for the absorption of acoustic waves in homogeneous mean flow...

We briefly review the use and the derivation of Generalized Impedance Boundary Conditions (GIBC) in the case of thin dielectric coating and in the case of strongly absorbing medium, within the context of electromagnetic scattering problem at a fixed frequency. We then numerically test the validity and accuracy of these boundary conditions in the case of high absorption. A numerical treatment of...

This paper investigates the feasibility to use an electrodynamic loudspeaker to determine viscoelastic properties of sound-absorbing materials in the audible frequency range. The loudspeaker compresses the porous sample in a cavity, and a measurement of its electrical impedance allows one to determine the mechanical impedance of the sample: no additional sensors are required. Viscoelastic prope...

The measurement of the microwave absorptivity of materials typically requires expensive and arcane equipment and methods. I show that, for moderately absorbing materials (loss tangent δ ' 0.005 or higher), useful measurements can be easily made using a thermometer and a normal domestic microwave oven: the heat absorbed for suitably designed sample size and geometry relates directly to the absor...