Abstract
We demonstrate a band-pass resonator in the terahertz (THz) range, based on a frequency-selective designer reflector. The resonator consists of a parallel-plate waveguide, a designed groove pattern cut into the output facet of each plate, and a reflecting mirror. The patterned facet supports a spoof surface plasmon mode, which modifies the reflectivity at the waveguide output facet by interacting with the waveguide mode. By tuning the geometrical parameters of the groove pattern, the reflectivity at the patterned output facet can be increased up to ∼100% for a selected frequency. Broadband THz waves are quasi-optically coupled into this resonator and reflected multiple times from the patterned facet. This leads to a narrowing of the spectrum at the selected frequency. The Q value of the resonator increases as the number of reflections on the patterned facet increases, reaching ∼25 when the THz wave has experienced 12 reflections.
Highlights
Enhanced reflection using spoof surface plasmonsThe plate spacing (b), groove depth (h), periodicity (d) and the distance from the first groove to the waveguide aperture edge (L) are varied to tune the frequency and strength of the surface plasmon coupling [1, 3, 11, 18, 19]
When an appropriate structure is cut into the output facet of the PPWG, another mode propagating on the output facet is introduced into the interplay and could lead to a significant change of the reflection coefficient [20]
The PPWG acts as the feeding circuit and the corrugated output facet acts as the antenna pad
Summary
The plate spacing (b), groove depth (h), periodicity (d) and the distance from the first groove to the waveguide aperture edge (L) are varied to tune the frequency and strength of the surface plasmon coupling [1, 3, 11, 18, 19]. The smaller the plate spacing, the more the waves at the output aperture are strongly diffracted, and the better coupling to the modes with orthogonal wave vectors, leading to a larger enhanced reflectivity (figure 3(d)). Because the plate spacing b of the PPWG and the sizes of the grooves are subwavelength in scale, the whole structure can be represented as a short dipole antenna as illustrated in figure 4(a) In this picture, the PPWG acts as the feeding circuit and the corrugated output facet acts as the antenna pad. As illustrated by the red curves in figure 3, the predictions of this simple analytical model, with a suitably chosen proportionality constant, show reasonable consistency with the FEM numerical simulations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
