Revisiting Modulated Johnson Noise Communication: A Critical Analysis of Novelty and Power Efficiency Claims in "Communication by means of modulated Johnson noise"

The 2022 PNAS paper by Kapetanovic et al. presents an experimental wireless communication system based on modulating Johnson (thermal) noise via impedance switching, claiming novelty as an “introduction” of this method and ultralow power operation comparable to RFID tags. This critique argues that the core concept is not new, representing a hardware realization of the foundational work by Kish in 2005, with experimental precedents in wired thermal noise systems. Furthermore, the “low-power” claim is overstated, as the receiver's amplification requirements consume significant energy (~20 W), undermining system-level efficiency. We provide evidence from prior literature, component specifications, and power calculations to support these points, highlighting the need for more accurate attribution and realistic efficiency assessments in passive noise-based communication research.