A method includes permitting a first signal having a first electromagnetic waveform to pass through an apparatus. The method further includes blocking a second signal having a second electromagnetic waveform at the apparatus, wherein the second electromagnetic waveform is different than the first electromagnetic waveform. The apparatus includes a non-conductive substrate and a plurality of cells including conductive members coupled to the non-conductive substrate, where the conductive members are arranged to form a first discontinuous mesh, where regions between the conductive members of the first discontinuous mesh include a phase change material, and where the phase change material undergoes a phase transition from substantially non-conductive to substantially conductive.