RF microphone. (a) Photograph of the experimental scenario. (b) Schematic illustration of procedures and results of sound source localization and recovery. (c–e) Comparison results of sound recovery regarding sound 1 (c), sound 2 (d), and sound 3 (e). Recovered sound signal is with time-domain (A) and time-frequency (B) representation, and the original sound signal is with time-frequency representation (C). (f) Sound recovery results from a cellphone’s microphone.