Design of the Reflectionless Absorber Based on the Principle of Band Stop Reflectionless Filter

In this article, a design method for the reflectionless absorber (RLA) is proposed based on the principle of the band-stop reflectionless filter (RLF). Compared with the traditional absorbing structures, the RLA can effectively absorb the electromagnetic (EM) waves within its operating band with small out-band reflection. Besides, the RLA has layer-independent characteristics due to its small reflection. Therefore, multiband and wideband RLAs can be achieved by simply stacking several single-band RLAs. After theoretical analysis and discussion of the single-band RLA, multiband and wideband RLAs are designed. Finally, two samples are fabricated to verify the presented design method. The theoretical calculated, simulated, and measured results agree well.