Frequency Selective Surface Unit Cell Research Articles

Application of Genetic Algorithm for the Optimization of Energy Saving Glass Coating Structure Design

Attenuation of GSM, GPS and personal communication signal leads to poor communication inside the building using regular shapes of energy saving glass coating. Thus, the transmission is very low. A brand new type of band pass frequency selective surface (FSS) for energy saving glass application is presented in this paper for one unit cell. Numerical Periodic Method of Moment approach according to a previous study has been applied to determine the new optimum design of one unit cell energy saving glass coating structure. Optimization technique based on the Genetic Algorithm (GA) is used to obtain an improved in return loss and transmission signal. The unit cell of FSS is designed and simulated using the CST Microwave Studio software at based on industrial, scientific and medical bands (ISM). A unique and irregular shape of an energy saving glass coating structure is obtained with lower return loss and improved transmission coefficient.

Design, Fabrication and Characterization of Fused Silica-Based Composites with an LTCC-Derived FSS

Laminated composites with a frequency selective surfaces (FSS) or more complex metamaterials are potential radome materials due to their unique characteristics of electromagnetic wave transmission. For making high-temperature resistant radomes, metamaterials or laminated composites with an FSS should be based on ceramic substrates. However, the processing methods for ceramic metamaterials are very limited and the conventionally used LTCC technique suffers from the shortcoming of large sintering shrinkage rates, which unfortunately impede the production of ceramic-based metamaterials. In this paper, a novel method of a low temperature co-fired ceramic (LTCC) technique combined with a technique of ceramic joining via green tapes was developed to fabricate the fused silica ceramic laminates sandwiched with the FSS. It was found that the newly developed composites with the FSS unit cells of the Ag-Pd strips exhibited near zero shrinkage of the unit cells, showed predictable transmission efficiencies of electromagnetic microwaves, and were able to overcome the poor transmission efficiencies below 11 GHz of the pure fused silica ceramic plates with an identical thickness.

Erratum: Frequency selective surface with switchable polarization

ABSTRACTThis article presents a novel frequency selective surface (FSS) with switchable polarization, which is realized using the improved cross slots with embedded strips and isolated island structure. The transmission characteristics of FSS unit cell for both horizontal polarization and vertical polarization are simulated with CST. And a FSS made of an array of 20 X 20 cells is implemented on the substrate Rogers RO4003. The experiment results show that the proposed FSS can obtain polarization switching through short and open circuits for X‐band application. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:515–518, 2014; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.28123. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1729, 2014

Application of Genetic Algorithm to the Design Optimization of Complex Energy Saving Glass Coating Structure

Attenuation of GSM, GPS and personal communication signal leads to poor communication inside the building using regular shapes of energy saving glass coating. Thus, the transmission is very low. A brand new type of band pass frequency selective surface (FSS) for energy saving glass application is presented in this paper for one unit cell. Numerical Periodic Method of Moment approach according to a previous study has been applied to determine the new optimum design of one unit cell energy saving glass coating structure. Optimization technique based on the Genetic Algorithm (GA) is used to obtain an improved in return loss and transmission signal. The unit cell of FSS is designed and simulated using the CST Microwave Studio software at based on industrial, scientific and medical bands (ISM). A unique and irregular shape of an energy saving glass coating structure is obtained with lower return loss and improved transmission coefficient.

Radar cross‐section reduction design for a microstrip antenna

ABSTRACTA microstrip antenna with reduced monostatic radar cross section (RCS) is presented. The RCS reduction is realized by replacing the solid ground plane of the reference antenna with a complex ground plane composed of bandstop frequency selective surface unit cells. In the mean time, the radiation performances are properly maintained. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1200–1204, 2014

Effect of unit-cells of the frequency selective surface as superstrate on the directivity of rectangular microstrip antenna

In this paper, the relationship between the number of unit-cells used in the design of a frequency selective surface (FSS) and its expected directivity is established. The relationship between the number of FSS unit-cells and the directivity is based on the planer microstrip patch array antenna design concept where the unit-cell is treated as the superstrate illuminated by the source. To validate the proposed technique, the analytical value of the directivity has been compared with that of ray-tracing method. The directivity of antenna is calculated for two different planar array configurations at 600 GHz. The results of numerical analysis are compared to that of the full-wave electromagnetic simulator CST Microwave Studio and results are comparable. Further, the directivity computed by this proposed technique has also been compared with that of the reported in literatures.

Frequency selective surface with switchable polarization

ABSTRACTThis article presents a novel frequency selective surface (FSS) with switchable polarization, which is realized using the improved cross slots with embedded strips and isolated island structure. The transmission characteristics of FSS unit cell for both horizontal polarization and vertical polarization are simulated with CST. And a FSS made of an array of 20 × 20 cells is implemented on the substrate Rogers RO4003. The experiment results show that the proposed FSS can obtain polarization switching through short and open circuits for X‐band application. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:515–518, 2014

Novel closely spaced planar dual‐band frequency‐selective surface

A novel, dual-band frequency-selective surface (FSS) is presented. The designed and fabricated FSS structure has closely spaced operation bands and high selective frequency response at each operation band. Two-dimensional compact U-shaped slot resonators are used in each FSS unit cell to obtain this ability. Also, each slot resonator is composed of straight slot section at the centre connected to two U-shaped arms at each end. The dimensions of the slot resonators are optimised using via full-wave electromagnetic simulations using CST Microwave Solver. The proposed FSS structure is independent of incident polarisation and angle because of 90° rotation of the unit cell. The validity of the proposed FSS is confirmed by both simulation and measurement results. In the experimental verification, a waveguide measurement setup is chosen. Both measurement and simulation results show that the FSS structure operates at the designed frequencies of 8.80 and 9.54 GHz, which are very close to each other.

FSS 단위 셀을 이용한 대역저지 UWB 안테나

본 논문은 주파수 선택 표면 (FSS)을 이용한 대역저지 ultra-wideband (UWB) 안테나를 제안한다. 제안된 안테나는 일반적인 FSS 단위 셀의 특성을 이용하여 UWB 대역 중 특정대역을 저지 할 수 있다. 안테나의 FSS 단위 셀구조는 UWB 안테나 구조체와 동일면에 설계하였으며, UWB 대역 (3.1-10.6 GHz) 중 무선 근거리 통신대역(5.15-5.825 GHz)의 간섭을 막기 위해 고안되었다. 제작된 안테나의 실제 측정된 이득은 저지 대역을 제외한 전 대역에서 2 dBi 이상이다. 제안된 안테나는 소형 모바일 장치에 적용이 가능 한 크기이며, 평판형 구조로 설계되어 다양한 FSS 단위 셀에 적용 할 수 있으며, 다양한 상용 UWB 시스템에 적용이 가능하다. Band-notched ultra-wideband (UWB) antennas using frequency selective surfaces (FSSs) are presented. The proposed antennas utilized the band rejection characteristic of typical FSS unit cells. We loaded the FSS unit cells on the same plane of planar UWB antenna. These antennas are designed to reject the interference from the wireless local area network band, 5.15-5.825 GHz in the UWB band, 3.1-10.6 GHz. The measured peak gains of the proposed antennas are more than 2 dBi at both operation edge and center frequencies, and sufficient to apply for commercial purpose. The antennas are small size and planar shape for the purpose of the small mobile application, and enhanced design freedom by using various existing FSS unit cells.

A FSS WITH STABLE PERFORMANCE UNDER LARGE INCIDENT ANGLES

In this paper, we propose a novel frequency selective surface (FSS) with stable performance under large incident angles. The FSS is composed of hexagon metallic lines and hexagon patches. Using such a hexagon arrangement, the periodicity size could be miniaturized and thus the FSS unit cell is compact. The composite FSS has an excellent stability under large incident angles. In the passband 10.58{ 11.06GHz, the insertion loss is still less than i1dB for both TE and TM polarizations, even under incident angle up to 85 degree. Both the design procedure and experimental results of the novel FSS are presented and discussed.

QUASI-OPTICAL FREQUENCY SELECTIVE SURFACE FOR ATMOSPHERIC REMOTE SENSING APPLICATION

The design of an efficient quasi-optics Frequency Selective Surface (FSS) filter which is required to provide a -3 dB pass band from 405 GHz to 441 GHz is presented. For atmospheric remote sensing application, this space-borne spatial device consists of a silicon layer and a thin copper layer which is perforated with periodic arrays of resonant dipole slots and circular apertures. FSS unit cell has a dimension much smaller than its operating wavelength. Unique features of this complex dense FSS structure include wide pass band properties with superb performance of frequency response and incident angles independence for TE polarization. Floquet mode analysis and finite element method (FEM) models are used to establish the geometry of the periodic structure and predict its spectral response.

A Chipless RFID Based on Multiresonant High-Impedance Surfaces

A novel chipless RF identification based on a multiresonant high-impedance surface is proposed. The structure is based on a finite metallic frequency-selective surface (FSS) comprising 2 × 2 (30 mm × 30 mm) or 3 × 3 (45 mm × 45 mm) unit cells. The FSS unit cell is formed by several concentric square loop resonators. The thin structure performs deep absorptions of the impinging signal at several resonant frequencies related to the loop resonators. If one of the printed loops in the unit cell is removed, the corresponding absorption peak disappears from the reflected signal giving the possibility of encoding a desired bit sequence. The proposed structure exhibits some intrinsic advantages, such as scalability (bit number increase) without any size increase, polarization independence, large read range, and the capability of operating when mounted on metallic objects. A transmission line model is employed to illustrate the operation principle of the structure, whereas measurements on realized prototypes are provided to assess the reliability and effectiveness of the proposed design.

Design and Performance of a Double-Layer Miniaturized-Element Frequency Selective Surface

In this letter, a novel bandpass frequency selective surface (FSS) is proposed. Unlike the traditional FSSs, our building block makes use of a periodic cell with much smaller size than the resonant wavelength. The proposed FSS is composed by two layers of metallic unit cells printed on the substrate. The coupling between parallel patches in different metallic layers can produce the significant distributed capacitance of the FSS; as a result, the size of the FSS unit cell can be decreased to λ/16. Our simulated result shows that the transmission characteristic of the miniaturized FSS is very stable since the relative change rate of resonant frequency is less than 2% with respect to different incident angles from 0 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> to 45 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> . The measured results show good agreements with the simulated ones. In addition, our result also implies that the structure has wide application space, based on analysis of three other variations on the periodic structure.

PMM-GA METHOD TO SYNTHESIZE QUASI-OPTICAL FREQUENCY SELECTIVE SURFACE ON SiO2 SUBSTRATE

A satellite-borne frequency selective surface (FSS) for atmospheric sensing application is presented. This brand new type of band-pass filter has an operating frequency at 183 GHz, which is a typical frequency on H2O absorption line. Comprising an ultrathin gilding layer and a SiO2 substrate layer, this complex periodic component exhibits an extremely low insertion loss ( 20 dB) between closely spaced frequency channels of 45 degrees incident wave. Periodic Method of Moment (PMM) approach is applied to determine the initial geometrical parameters of FSS unit cell, and the optimization approach based on the Genetic Algorithm (GA) enables us to obtain the requisite spectral response and transmission characteristics for both TE and TM polarization. The experimental results show that the proposed PMM-GA technique is effective for analyzing space-borne FSS at millimeter wave range.

마이크로파 전송선로에 삽입된 주파수 선택 표면을 이용한 광대역 대역저지필터

본 논문은 마이크로스트립 전송선로에 삽입된 주파수 선택 표면(FSSs)을 사용하여 주기적인 구조를 갖는 대역저지필터(BSF)에 관한 것이다. 제안된 대역저지필터는 변형된 크로스 루프 슬롯 (Cross-loop slot)을 단위 셀로 하여 주기적인 구조로 설계하였으며, 설계된 대역 저지 필터는 등가회로 모델과 분산 도표(dispersion diagram)로 해석하였다. 대역 저지 필터의 중심주파수(fo)는 6.6 GHz이다. 제안된 필터는 단위 셀의 개수가 증가하면 3dB 대역폭은 넓어지고 삽입손실은 줄어드는 특성이 있다. 또한 제안한 대역저지필터는 소형의 평면구조를 가지며, 한 번의 에칭으로 제작이 가능 하여 다양한 분야의 RF 필터로서 사용 가능성이 높다. This article presents a band-stop filter (BSF) by using a periodic structure property of frequency selective surfaces (FSSs) embedded in a microstrip transmission line. The proposed BSF is designed with FSS unit cells modifying the cross-loop slots. The BSF is interpreted with an equivalent circuit model and a dispersion diagram. The center frequency (fo) of the BSF is 6.6GHz. Proposed filter increases the number of unit cell. As a result, 3dB bandwidth is wider and insertion loss is reduced. Also, Facbricated BSF exhibits uniplanar geometry, simple fabrication.

Bandstop Filter Design for GSM Shielding Using Frequency Selective Surfaces

In this paper, the performance of bandstop Frequency Selective Surface (FSS) is presented which can be used to provide wireless security on airports and other sensitive places, where a mobile phone can be used to set-off an explosive device. It can also be used to block the mobile signals at the places of worship, hospitals and cinemas where the annoying voice of a mobile phone may irritate the masses. The FSS unit cell consists of two metallic square-loop elements printed on FR-4 substrate with different periodicities. The outer and inner square-loop elements are tuned to 900 MHz and 1800 MHz, respectively. It has a stable frequency response at oblique incidences for both perpendicular (TE) and parallel (TM) polarizations. Simulation results are presented to give an overview for the performance of proposed FSS design. DOI: http://dx.doi.org/10.11591/ijece.v2i6.1820 Full Text: PDF

Band-notched planar UWB antenna using unit cells of frequency selective surfaces

Band-notched ultra-wideband (UWB) antennas using frequency selective surfaces (FSSs) are presented. The proposed antennas utilized the band rejection characteristic of typical FSS unit cells. We loaded the FSS unit cells on the same plane of planar UWB antenna. These antennas are designed to reject the interference from the wireless local area network band, 5.15–5.825 GHz in the UWB band, 3.1–10.6 GHz. The measured peak gains of the proposed antennas are more than 2 dBi at both operation edge and center frequencies and sufficient to apply for commercial purpose. The antennas have small size and planar shape for the purpose of the small mobile application, and enhanced design freedom by using various existing FSS unit cells.

A Versatile Design Strategy for Thin Composite Planar Double-Sided High-Impedance Surfaces

A novel methodology is introduced for the design synthesis of thin planar realizations of volumetric high-impedance or artificial magnetic conducting surfaces (AMC). The design synthesis involves optimization of two different metallic frequency selective surface (FSS) type structures printed on each side of a thin dielectric substrate material. This technique eliminates the need for a complete metallic backplane common in conventional AMC designs, making use of the same dielectric substrate for two high-impedance surfaces; one on each side. Optimization of the FSS unit cell geometries is carried out with a robust genetic algorithm (GA) technique that is combined with a full-wave periodic finite element boundary integral (PFEBI) electromagnetic simulation code for fast and accurate optimization of desired AMC performance at a single frequency or over multiple frequency bands. Several examples of thin AMC ground planes are optimized for use in the X-band. Additional design examples that provide AMC behavior on one side and absorber behavior on the other are also provided. Lastly, an example illustrating the utility of the double-sided AMC separator structure is shown for a design targeting the standard Wi-Fi frequencies of 2.4 GHz and 5.2 GHz.

BROAD BAND-STOP FILTER USING FREQUENCY SELECTIVE SURFACES IN UNIPLANAR MICROWAVE TRANSMISSION LINE

We present a band-stop fllter (BSF) by using a periodic structure property of frequency selective surfaces (FSSs) embedded in a microstrip transmission line. The proposed BSF is designed with FSS unit cells modifying the cross-loop slots. The center frequency (fo) of the BSF is 6.6GHz, and the 3-dB bandwidth varies by the number of cascading unit cells. The BSF is interpreted with an equivalent circuit model and a dispersion diagram, and exhibits uniplanar geometry, low return loss, simple fabrication, smaller size, and wide bandwidth.

ASK modulator based on switchable FSS for THz applications

[1] An amplitude shift keying modulator that is based on a switchable frequency selective surface (FSS) is described for THz communication. The FSS uses a square loop aperture geometry, with each unit cell having four PIN diodes across the aperture at 90 degree intervals. To minimize the effect of bias lines on the overall frequency response of the FSS, a crossed-shape negative dc bias line, which is connected to the center of the FSS unit cell, has been placed on the rear surface of the dielectric substrate. Positive dc biasing is provided from the front side of the FSS structure. Simulation results are presented for two possible operating frequencies and two principal polarizations at normal and oblique incidence. These show that a free space modulator based on the proposed FSS structure would provide about 19 dB transmission loss at 600 GHz between on and off states of the PIN diodes for both transverse electric and transverse magnetic polarizations.