TY - JOUR
T1 - Terahertz two-layer frequency selective surfaces with improved transmission characteristics
AU - Vegesna, Subash
AU - Zhu, Yanhan
AU - Bernussi, Ayrton
AU - Saed, Mohammad
PY - 2012
Y1 - 2012
N2 - 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.
AB - 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.
KW - Frequency selective surfaces (FSS)
KW - THz filters
KW - THz time-domain spectroscopy (TDS)
KW - multilayer terahertz (THz) FSS
UR - http://www.scopus.com/inward/record.url?scp=84863903523&partnerID=8YFLogxK
U2 - 10.1109/TTHZ.2012.2202035
DO - 10.1109/TTHZ.2012.2202035
M3 - Article
AN - SCOPUS:84863903523
VL - 2
SP - 441
EP - 448
JO - IEEE Transactions on Terahertz Science and Technology
JF - IEEE Transactions on Terahertz Science and Technology
SN - 2156-342X
IS - 4
M1 - 6236290
ER -