Overcoming the Pixel-Density Limit in Plasmonic Absorbing Structure for Broadband Absorption Enhancement

In this letter, our investigation shows that the pixel-density limit of wire element in plasmonic absorbing structure (PAS) has always been an obstacle to the achievement of broadband and highly effective absorption. Aiming at this, a comprehensive scheme of PAS based on the combination of multi-meandered wire arrays with deliberately regulated period is proposed that takes the advantage of spatial dispersion engineering to excite more multiple resonances, contributing to an enhancement of average absorbing efficiency in a wider frequency band. Simulation and experimental measurement show that our proposed combined PAS can achieve broadband absorption with the efficiency more than 90% in the frequency band of 9.0-35.0 GHz, which has 5.2% higher averaged absorbing efficiency with respect to the original PAS at the same thickness. Our strategy provides an effective way to overcome pixel-density limit for broadband absorption enhancement in PAS with simultaneous lightweight and easy-fabrication characteristics, enabling a wide range of applications.