• Proceedings of the IEEK Conference
• /
• 1999.11a
• /
• pp.837-840
• /
• 1999

It is difficult to analyze the impact of interference of NGSO/FSS systems on a GSO/FSS network because of time-varying nature of NGSO/FSS systems. In this paper, we present an efficient method to assess the impact of interference of NGSO/FSS satellite networks on the GSO/FSS carrier performances. The example analysis shows the impact on the GSO/FSS carrier performances in terms of elevation angles of earth stations in a GSO/FSS system.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.43 no.4 s.346
• /
• pp.58-66
• /
• 2006

This paper proposes an FSS(Frequency Selective Surface) design system that automatically derives design parameters minimally specified by engineers. The proposed system derives optimal design parameters through theory of electromagnetic scattering on FSS, database implemented from real data obtained from practically manufactured FSS, and GA(Genetic Algorithm) for optimizing design parameters. The system, at the first step, searches the best matching FSS within preconstructed DB with given characteristics specified by operators, and then sets initial genes from the searched FSS parameters. GA iterates the optimization process until the system finds the FSS design parameters that matches the characteristics specified by operators. The theory for the electromagnetic scattering on FSS is verified by comparing the simulation results with real data obtained by measuring system composed of horn antenna and receiver. The process for manufacturing the FSS is also included in the paper.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.2
• /
• pp.127-136
• /
• 2008

This paper proposes the efficient system for automatic design of FSS(Frequency Selective Surface) with periodic pattern and frequency characteristics specified by operator. The proposed system derives optimal design parameters through tool for analysis of FSS with arbitrary pattern, DB(Data Base) implemented from limited simulation and measurement data of FSS, and GA(Genetic Algorithm) for optimizing design parameters. FSS analysis tool consists of two analysis tools. One is the simulator for analysis of monolayer FSS that using moment method, another is the tool with approximated analysis method of FSS with dielectric layer. Given pattern configuration and characteristics specified by operators, the DB system searches the best matching FSS, and provides initial genes to GA from the searched parameters, which drastically reduces running time of GA for finding the FSS design parameters. In this paper, the proposed design system is verified through simulation and measurement about FSS with various patterns.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.20 no.4
• /
• pp.366-374
• /
• 2009

ITU has considered the 3,400$\sim$4,200 MHz band, which is allocated worldwide on a primary basis to the FSS, as a candidate band for future development of IMT system. In this band, this paper presents the results of the sharing studies performed between FSS and IMT systems through the theoretical and simulation analysis on the interference from multiple IMT base stations into a receiving FSS earth station considering the interference mitigation techniques such as antenna tilt angle and 3 sectors on the IMT base station. By using the long-term and short-term interference threshold, the coordination areas for the FSS earth station are provided to share frequency in 3,400$\sim$4,200 MHz band between FSS earth station and multiple IMT base stations in future.

• Steel and Composite Structures
• /
• v.19 no.6
• /
• pp.1501-1510
• /
• 2015

The frequency selective surface (FSS) embedded hybrid composite materials have been developed to provide excellent mechanical and specific electromagnetic properties. Radar absorbing structures (RASs) are an example material that provides both radar absorbing properties and structural characteristics. The absorbing efficiency of an RAS can be improved using selected materials having special absorptive properties and structural characteristics and can be in the form of multi-layers or have a certain stacking sequence. However, residual stresses occur in FSS embedded composite structures after co-curing due to a mismatch between the coefficients of thermal expansion of the FSS and the composite material. In this study, to develop an RAS, the thermal residual stresses of FSS embedded composite structures were analyzed using finite element analysis, considering the effect of stacking sequence of composite laminates with square loop (SL) and double square loop (DSL) FSS patterns. The FSS radar absorbing efficiency was measured in the K-band frequency range of 21.6 GHz. Residual stress leads to a change in the deformation of the FSS pattern. Using these results, the effect of transmission characteristics with respect to the deformation on FSS pattern was analyzed using an FSS Simulator.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.20 no.2
• /
• pp.147-153
• /
• 2009

In this paper, FSS(Frequency Selective Surface) using defect mode characteristic is proposed. The unit cell using defect mode characteristic of the proposed FSS is offered lower resonant frequency in the same cell size. The number of suitable array is optimized 13 by 13. Also, the patch antennas operated in WCDMA(Wideband Code Division Multiple Access) Tx band and Rx band are designed for the comparison. The gain value of proposed FSS-1 complex structure (the patch antenna of Tx band and FSS) is improved 3.3 dB from 9.98 dBi to 13.28 dBi in Tx band. The gain value of proposed FSS-2 complex structure(the patch antenna of Rx band and FSS) is improved 5.53 dB from 9.81 dBi to 15.34 dBi in Rx band. Also the measured impedance bandwidth($VSWR{\leq}2$) of manufactured $13{\times}13$ array antenna is from 337 MHz(1.87 to 2.21 GHz). The measured radiation gain is 11.39 dBi(1.94 GHz), 13.11 dBi(2.05 GHz), 11.09 dBi(2.14 GHz). The measured radiation efficiency is 81 %. Because the proposed FSS structure has more higher gain, it will be applied to antenna of WCDMA repeater system.

• Journal of electromagnetic engineering and science
• /
• v.10 no.3
• /
• pp.86-91
• /
• 2010

In this paper, a double-layered frequency selective surface(FSS) superstrate was built and tested. The unit cell of the proposed FSS consists of a ring slot and a dipole-shaped structure and shows a complementary frequency response. Each unit cell is printed on two sides of a substrate. By using these double-layered structures, the first resonant frequency of the pass-band can be lowered. As a result, the size of the unit cell is minimized and the spacing between the other cells is reduced. The proposed FSS-dipole composite antenna is designed for the gain enhancement of wide-band code division multiple access(WCDMA) frequency bands(1.92~2.17 GHz) with a low quality factor(Q=0.17). To verify the gain enhancement performance of the FSS, an FSS-dipole composite antenna was created. Although the FSS layer enhances the gain of the primary radiation source of the dipole antenna, the FSS-dipole complex antenna cannot show a uniform gain over the entire desired frequency band. The experimental results show a gain enhancement of 3 dBi with an FSS superstrate in the WCDMA frequency band.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.7
• /
• pp.775-782
• /
• 2016

In this paper, we presented the paper-based reconfigurable frequency selective surface(FSS) for transmitting or blocking the wireless LAN signal in indoor environments. The proposed reconfigurable FSS are designed on coated paper using a printing of conductive ink and conductive adhesive for PIN diode, which provides ON/OFF of the reconfigurable FSS for passing or blocking the 5GHz signal. The reconfigurable FSS attached on the wall can pass or block the incident wireless signal as the received signal strength in indoor. To provide the validity of the proposed FSS, we fabricated the reconfigurable FSS on the paper and confirmed the very similar results between simulations and measurements. From the measured results of the proposed spectrum control system, we know that the proposed reconfigurable FSS can block about 20dB at 5.745GHz~5.805GHz.

• Journal of Advanced Navigation Technology
• /
• v.14 no.5
• /
• pp.587-595
• /
• 2010

Spectrum sharing between wireless systems becomes a critical issue clue to emerging new technologies and spectrum shortage. Recently, IMT system has been allocated in the same frequency C band (3400-4200MHz) along with FSS services on co-primary basis which means that harmful. interference probability may be inspired. In this paper, to estimate the spectrum sharing between IMT and FSS systems, I propose the minimum separation distances as a sharing criterion of I/N=-10dB using the interference to noise ratio(I/N) received at the reference FSS earth station from IMT multiple base station. Especially, same results imply that I/N values can be greatly reduced with MMO SDMA interference mitigation technique of IMT base station so that FSS and IMT systems can co-exist in the sam e frequency with appropriate separation distance.

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