Terahertz two-layer frequency selective surfaces with improved transmission characteristics

Subash Vegesna, Yanhan Zhu, Ayrton Bernussi, Mohammad Saed

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


In this paper, a cascaded configuration for two-layer frequency selective surfaces (FSSs) at terahertz (THz) frequencies with improved filtering characteristics is realized for electrically thick substrates. At THz frequencies, the thicknesses of commercially available substrates are comparable to the free-space wavelength. As a result, the substrate plays a critical role in determining the transmission characteristics of THz multilayer FSS structures. Proper coupling method between FSS structures should be chosen to avoid unwanted substrate resonances or Fabry-Pérot resonances, which otherwise degrade the transmission characteristics of the cascaded FSS structure. In this paper, a cascaded structure to avoid multiple reflections within the substrate is presented and the same is used to realize two double-layered FSS structures to improve the transmission response. The transmission response is improved by introducing an extra transmission zero at a frequency location lower than the resonant frequency, thereby achieving high roll-off rate for the lower side of the stop band, and to suppress unwanted resonances, thereby increasing the rejection bandwidth of the filter. The proposed cascaded FSS structures were fabricated and tested using THz time-domain spectroscopy. Good agreement between simulations and experiments were obtained.

Original languageEnglish
Article number6236290
Pages (from-to)441-448
Number of pages8
JournalIEEE Transactions on Terahertz Science and Technology
Issue number4
StatePublished - 2012


  • Frequency selective surfaces (FSS)
  • THz filters
  • THz time-domain spectroscopy (TDS)
  • multilayer terahertz (THz) FSS


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