Broadband and Ultrathin Metamaterial Absorber Fabricated on a Flexible Substrate in the Long-Term Evolution Band

In the low-frequency regime, we demonstrated an efficient broadband metamaterial absorber (MA) by integrating an active low-conductivity ground plate into the common sandwiched structure. The energy of every electromagnetic (EM) wave radiated from the ultrahigh frequency to the long-term evolution band is trapped inside an ultrathin/flexible MA, which has a thickness of only λ/1362 at the lowest working wavelength. This performance of proposed MA in the defined band is also predicted through a simplified equivalent-circuit model and the simulation. Correspondingly, our MA absorbs over 90% in the wide band from 0.2 GHz to 3.6 GHz (fractional bandwidth of 179.0%). In particular, this MA also exhibits the stable features of omni-directionality (incident angle up to 40°) and polarization independence of the EM waves. Our innovation offers a different approach to realize the potential wearable smart meta-devices by using these ultrathin broadband MAs.