A Metacoupler for Converting Propagating Waves to Guided Waves in Wire Waveguides

Propagating electromagnetic waves in free space cannot directly couple to guided waves in waveguides due to momentum mismatch. Here, we propose a method to design a metacoupler that can convert propagating waves into guided waves along wire waveguides in a noninvasive way. The metacoupler is attached to the wire waveguide and imposes an additional wave vector to the scattered waves, thus, filling the momentum gap between the propagating waves and guided waves. Numerical simulations have confirmed the conversion effect in corrugated metal wire and silicon wire waveguides.