Electromagnetic absorption and shield properties of lossy composite multilayers

The fundamental absorption properties of lossy composite multilayers in the range from high-frequency waves to microwaves are discussed. Measurements of the reflection and transmission factors of multilayer disk absorbers at 11.6 GHz were made. The disk absorbers were made of vinyl chloride and carbon or aluminum or copper. The radius and thickness were 65.0 mm and 10.8 mm, respectively. The reflection factor and transmission factor were -17 dB and -26 dB for an incidence angle of 10°. In order to determine the relationship between the electromagnetic absorption and the distribution of constants, calculations are made using the characteristic matrix method. It is shown that the increase of permittivity and conductivity with the direction of stratification improves the absorption characteristics. Distributions of electric and magnetic fields in the multilayer are evaluated