• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.1
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• pp.1-9
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• 2018

In this paper, we propose a film-type dual-band frequency selective structure for improving the wireless communication environment in a building. The proposed frequency-selective structure is a miniaturized structure that can control the resonant frequencies of 2.4 GHz and 5 GHz dual band through simple design parameters. We fabricated the frequency-selective surface by screen printing using conductive ink on a thin transparent film and confirmed its performance by measurement. We analyzed the attenuation performance of the unnecessary signal from the outside when the frequency-selective structure designed using the software to analyze the propagation environment performance is applied to the building. To verify the analytical results, the signal strength of the indoor environment was measured by applying the frequency-selective film fabricated on the inner wall of the actual building. The measurement results show that the dual-band frequency-selective film has 29.4 dB and 15.94 dB attenuation performance in the 2.4 GHz and 5 GHz, respectively.

• Journal of the Optical Society of Korea
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• v.19 no.6
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• pp.673-678
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• 2015

Terahertz dual-band frequency selective surface filters made by perforating two different rectangular holes in molybdenum have been designed, fabricated and measured. Physical mechanisms of the dual-band resonant responses are clarified by three differently configured filters and the electric field distribution diagrams. The design process is straightforward and simple according to the physical concept and some formulas. Due to the weak coupling between the two neighboring rectangle holes with different sizes in the unit cell, good dual-band frequency selectivity performance can be easily achieved both in the lower and higher bands by tuning dimensions of the two rectangular holes. Three samples are fabricated, and their dual-band characteristics have been demonstrated by a THz time-domain spectroscopy system. Different from most commonly used metal-dielectric structure or metal-dielectric-metal sandwiched filters, the designed dual-band filters have advantages of easy fabrication and low cost, the encouraging results afforded by these filters could find their applications in dual-band sensors, THz communication systems and other emerging THz technologies.

• Journal of IKEEE
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• v.27 no.1
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• pp.71-77
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• 2023

In this paper, a dual-band stopband frequency selective surface that can be applied to Wi-Fi 6E systems is designed to block external interfering signals with adjacent operating frequency spectrum in indoor wireless LAN environments. The proposed frequency selective surface structure has frequency blocking characteristics in the 2.4GHz and 6GHz bands, and is realized through a modified crossed dipole structure and an interlocking puzzle form between unit structures. The proposed structure is designed to have stable frequency response characteristics with respect to incident angle and polarization, and the experimental results show good agreement with the simulation results for incident waves from 0° to 45°.

• ETRI Journal
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• v.39 no.1
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• pp.69-75
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• 2017

This study presents a dual-band 3D frequency selective surface that provides a large degree of freedom in frequency and bandwidth adjustability. The proposed structure is evaluated in terms of its structural parameters, and prototypes are fabricated. The radius of the copper rings and the height of the cylinders are considered, and are shown through full-wave electromagnetic simulations to have a significant effect on the frequency characteristics of the frequency selective surface. The measurement results of the fabricated samples are compared with the simulation results, and a satisfactory agreement is obtained.

• ETRI Journal
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• v.31 no.1
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• pp.77-79
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• 2009

The wave concept iterative procedure (WCIP) is used to analyze a quasi-square open metallic ring frequency selective surface (FSS). The quasi-square open metallic ring FSS is dual-polarized. When the incident plane wave is polarized in a direction parallel to the FSS' coupled parallel strips, it shows two rejecting bands. Moreover, another rejecting band can be obtained if the source plane wave is perpendicularly polarized with respect to the FSS' coupled parallel strips. The three resonant frequencies are inversely proportional to the length of the FSS' coupled strips to provide an easy fine tuning of the FSS structure. The simulated results obtained using WCIP are compared to the measured results, and a good agreement is reported.

• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.34-39
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• 2015

In this paper, a design of an offset Cassegrain antenna is proposed for Ku and Ka dual-band without increasing the antenna size. For Efficiency of computation and implementation, the frequency selectivity surface (FSS) of reflecting the Ka-band signal and passing the Ku-band is provided for the sub-reflector instead of the main reflector. The proposed FSS hyperboloid sub-reflector is the periodic structure of a unit cell comprising octagon metal rings embedded in the multiple layers. The proposed design is verified for 19 GHz and 45 GHz bands by the use of precise electromagneitc-field simulations.