A Discrete Slab Absorber: Absorption Efficiency and Theory Analysis

Slab absorber is an important topic not only for military purposes but also for commercial application. Single-layer compact slab absorber cannot meet the required wave absorption in broad wave band besides some absorption peaks, and it is very necessary to develop a new kind of absorber to meet the need of absorption in broad wave band. In this study, a discrete slab absorber (DSA) has been developed by isolating conductive medium in absorbing matrix, and the reflection loss test indicates that the DSA exhibited excellent absorption effectiveness at 8-18 GHz. With the increasing carbon black (CB) content of the isolated conductive particles in the slab absorber, the reflection loss increases in the range 8-18 GHz. When mass fraction of CB gets to 30%, the reflection loss is below 10 dB in the range 8.5-18 GHz, and the effective absorption band below 10 dB gets to 9 GHz. In comparison, the compact slab sample with 30 mass% CB only shows two absorption peaks and the effective absorption band below 10 dB is under 1 GHz. Finally, an absorption mechanism is suggested.