Optically transparent frequency selective surfaces on flexible thin plastic substrates

Abstract

A novel 2D simple low cost frequency selective surface was screen printed on thin (0.21 mm), flexible transparent plastic substrate (relative permittivity 3.2). It was designed, fabricated and tested in the frequency range 10-20 GHz. The plane wave transmission and reflection coefficients agreed with numerical modelling. The effective permittivity and thickness of the backing sheet has a significant effect on the frequency characteristics. The stop band frequency reduced from 15GHz (no backing) to 12.5GHz with polycarbonate. The plastic substrate thickness beyond 1.8mm has minimal effect on the resonant frequency. While the inner element spacing controls the stop-band frequency, the substrate thickness controls the bandwidth. The screen printing technique provided a simple, low cost FSS fabrication method to produce flexible, conformal, optically transparent and bio-degradable FSS structures which can find their use in electromagnetic shielding and filtering applications in radomes, reflector antennas, beam splitters and polarizers.

Polarization Insensitive and Transparent Frequency Selective Surface for Dual Band GSM Shielding

“…In reality, the optical visibility is not as good as our printed Ag NWs, because pure copper sheet has been used. Although the FSSs reported in [22] and [34] are printed, the opaque silver inks used in the printing process make them unsuitable for applications requiring higher optical transparency. Also, it is extremely difficult to modify the FSS designs reported in [22] and [34] for multi-band operations.…”

“…Although the FSSs reported in [22] and [34] are printed, the opaque silver inks used in the printing process make them unsuitable for applications requiring higher optical transparency. Also, it is extremely difficult to modify the FSS designs reported in [22] and [34] for multi-band operations. In Table I, we have compared all the closely related transparent FSS works with our proposed transparent FSS design (all works owe the transparency to the material property and not to the etched mesh structures or opaque Ag paste).…”

“…Some papers have reported printed FSS structures [31][32][33], but none has been realized through a transparent ink. A couple of papers report optically transparent FSS designs based on printed meandered structures [22,34], where metal pastes with high solid content have been utilized for printing, and the optical transparency has been achieved through the uncovered areas of the designed patterns. This kind of FSSs typically demonstrates low optical transparency due to the opaque nature of the conductive materials.…”

Comparative Study of Square and Circular Loop Frequency Selective Surfaces for Millimeter-Wave Imaging Diagnostics Systems

“…When the oblique incidence angle performance of the FSS is important, the gap between adjacent elements g should be less than half of the free space wavelength to avoid the scattering of the signal. However, for the normal incidence, the gap g can be equal to or less than one wavelength [ 30 , 31 ]. Though there exist the distinct main influences of the aforementioned parameters on the frequency response of the FSS, however, they all contribute more or less in the shift of the FSS resonant frequency.…”

Design of Security Paper with Selective Frequency Reflection Characteristics

“…Recently, there has been a study on FSS which is manufactured by a printing method using conductive ink on a flexible substrate such as film or paper. There are a lot of film-based studies because it is easy to form a conductive pattern using a printing method on a film and a high-resolution FSS can be produced according to a printing technique when a film is used as a substrate to fabricate an FSS [ 12 , 13 , 14 ]. A study on FSS based on paper has been carried out on FSS with Wi-Fi band cut-off characteristics produced by a printing method using paper as a substrate in 2015 [ 15 ].…”