(a) Schematic of the polarization-independent absorber. (b) Structure of the polarization-independent absorber. (c) Reflectivity of the polarization-independent absorber from the simulation and measurement [103]. Reproduced with permission from Y. Yang et al., 2019 International Symposium on Antennas and Propagation (ISAP), IEEE, 1, 4 (2019). Copyright 2019 IEEE. (This figure is subject to copyright protection and is not covered by a Creative Commons Commons license.)