Fig. 3: Schematic of the system framework and some core SPP devices for the newly proposed subdiffraction-limit transmission system.

a System framework schematic of the SPP wireless communication system. By introducing spoof SPPs, a series of inherent signal interference problems in adjacent subdiffraction-limit channels, including leaky waves and continuous-part coupling, can be solved from the basic physical view without any extra cost. b The measured frequency spectrum of the shared local oscillator, which can spontaneously generate a continuous carrier wave at 10 GHz, and of the coded signal (inset). c The measured frequency spectrum and structure (inset) of a designed ultracompact filter, which can block the fundamental signal at approximately 10 GHz. d The measured frequency spectrum and the 3-D gain of the antenna, which can transmit signals in the designed frequency band with weak directivity and high efficiency