Fig. 2

The wireless text-communication using EBCM. a The system architecture of the text-communication system as well as the coding and decoding process. b–d The encoding process from EEG signals to the transmitted EM signals, where the EEG signals shown in b are first detected by BCI and translated into the digital sequence in c for wireless transmission, then radiated by the metasurface with different pattern amplitudes in d. e–g The decoding process of wireless communication, where the antenna and FPGA in e firstly receive and sample the signals from space and convert them into the digital signals. The sampled data are discretized into 0/1 codes for decoding, as depicted in f and finally translated into the text for display