Design of an ultra-broadband absorber based on plasma metamaterial and lumped resistors

An electromagnetic absorber is realized based on the plasma metamaterial and lumped resistors. For a TE wave, the tunable absorption spectra can be obtained, and the properties of absorption can be improved by exciting the different plasma resonance structures. The proposed absorber can work in S, L and C bands, which is covered at 1.6115-4.0798 GHz (absorption rate is larger than 0.9), and its relative bandwidth is 86.7%. However, for a TM wave, the reflection coefficient is near to 1. The proposed electromagnetic absorber not only can realize the ultra-broadband absorption for the TE wave, but also can act as a reflector for the TM wave. A polarization splitter can be realized by such an absorber. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement