Electromagnetic Metamaterial Absorbers: From Narrowband to Broadband

Abstract

Metamaterial perfect absorbers have received significant attention owing to their ability of achieving complete absorption of the electromagnetic waves with deeply subwavelength profiles. In this chapter, we will present a general review of the recent progress on theories, designs, and characterizations of metamaterial absorbers. We will first review the fundamental theories and design guidelines for achieving perfect absorption in subwavelength metamaterials. Several typical narrowband metamaterial absorbers are then presented with nearly 100% absorptivities. Next, we will focus on the realizations of broadband and frequency-tunable metamaterial absorbers. Coherent perfect absorbers, whose absorption performances are controllable via the interference of two counter-propagating electromagnetic waves, will also been introduced. In particular, we will also focus on the recent achievements of metamaterial absorbers in our research group