Abstract-Second-Order Terahertz Bandpass Frequency Selective Surface With Miniaturized Elements

Ebrahimi, A. Nirantar, S. ; Withayachumnankul, W. ; Bhaskaran, M. ; Sriram, S. ; Al-Sarawi, S.F. ; Abbott, D.
School of Electrical & Electronic Engineering, The University of Adelaide, Adelaide, Australia 
http://ieeexplore.ieee.org/xpl/articleDetails.jsp?reload=true&arnumber=7166337
In this paper, a second-order frequency selective surface (FSS) made of miniaturized elements is proposed and designed for terahertz applications. The FSS is composed of two layers of metallic arrays separated from each other by a polymer dielectric spacer. The unit cells on the front and back layers are smaller than  , where  is the free space wavelength. The operation principle of the proposed FSS is described through a circuit model, and a synthesis procedure is presented for designing a desired filtering response. A prototype of the FSS is synthesized to operate at a center frequency of 0.42 THz with 45% fractional bandwidth. The designed FSS is fabricated by using microfabrication process. The performance is evaluated by using terahertz time-domain spectroscopy. Measurement results show a low sensitivity of the FSS response to oblique angles of incidence for both of the TE and TM polarizations.

Article-Plasmonics: Terahertz Localized Surface Plasmon Resonances in Coaxial Microcavities

http://onlinelibrary.wiley.com/doi/10.1002/adom.201370038/abstract
Withayachumnankul, W., Shah, C. M., Fumeaux, C., Kaltenecker, K., Walther, M., Fischer, B. M., Abbott, D., Bhaskaran, M. and Sriram, S.
Coaxial microcavities etched into the surface of a heavily-doped silicon substrate by W. Withayachumnankul, S. Sriram, and co-workers are shown on page 443 to support localized surface plasmon resonances at terahertz frequencies through the interplay between the cylindrical surface plasmon polaritons and the cavity modes. The coaxial geometry partly determines the resonance frequency, as illustrated by the absorption map.