The engineering way from spoof surface plasmon polaritons to radiations

In recent years, spoof surface plasmon polaritons (SPPs) have been investigated at microwave and THz frequencies for engineering purpose. Due to momentum mismatch, the SPP mode cannot be directly converted from the spatial mode, and vice versa. Stimulating schemes have been developed to transform spatial waveguide modes to SPP modes with high efficiency. On the other hand, the question may arise that, is it possible to transform the propagating SPP waves to directive radiating waves for wireless communication? In view of this, this paper introduces the new-concept antennas based on spoof SPPs at microwave frequencies. Methods of transforming SPP modes to radiating modes are studied, whilst a series of antenna designs are presented and discussed. Feeding networks for antenna arrays using SSPP TLs are also investigated. Most works reviewed in this paper are fulfilled at Southeast University in China.