fig3

Figure 3. EMG-based SSIs. (A) Working principle of EMG-based SSIs; (B) Dry electrode made by gold thin films for SSIs. Adapted from Ref. [63], under CC BY 4.0 license; (C). Dry electrode based on AgNWs for SSIs. Adapted with permission from Ref. [5] Copyright 2023, Wiley-VCH; (D) Wet electrode based on ion gels for SSIs. Adapted with permission from Ref. [64] Copyright 2023, Wiley-VCH. EMG: Electromyography; SSIs: silent speech interfaces; AgNWs: silver nanowires; Difff. Amp.: differential amplifier; PET: polyethylene terephthalate; SEM: scanning electron microscope.