Patch antenna arrays for efficient coupling of terahertz spoof surface plasmon polaritons to free space modes and for substance monitoring

Abstract

We report the implementation of compact patch antenna arrays that function as highly directive output couplers for strongly confined terahertz spoof surface plasmon polaritons (SSPPs). The specifically designed circular patches can efficiently transfer the energy of confined SSPPs on metasurfaces into radiating waves with a well-defined radiation pattern in free space. Since materials close to the metasurface impact the propagation of the SSPPs, the attenuation of the SSPPs translates into a power change of the radiated waves from the patch antennas, thus enabling sensitive detection of substances in the SSPP pathway.