scholarly journals A double layer FSS filter for sub-THz applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. Ghavidel ◽  
M. Kokkonen ◽  
S. Myllymäki
Keyword(s):  
Dielectric Permittivity ◽  
Double Layer ◽  
Single Layer ◽  
Frequency Selective Surface ◽  
Unit Cell ◽  
Center Frequency ◽  
Low Dielectric ◽  
Microwave System ◽  
Cascaded Filter ◽  
Thz Applications

AbstractThis work presents the simulated and measured performance of single- and double-layer frequency selective surface filters for operation at sub-THz frequencies (250 GHz center frequency). They were composed of concentric square loops with a split as a unit cell resonator on top of a low dielectric permittivity, low thickness material (RT5880). Both a single layer filter and a cascaded two layer filter with varied distances were investigated. The simulated bandwidth for the cascaded filter was 27 GHz and 16 GHz and 9 GHz bandwidth measured with a THz-TDS and microwave system.

Longitudinal slotted waveguide array feed networks

2018 ◽  
Vol 10 (4) ◽  
pp. 512-517 ◽  
Author(s):  
J. Soleiman Meiguni ◽  
S. Keshavarz Haddad ◽  
A. Hosseinbeig
Keyword(s):  
Double Layer ◽  
Layer Structure ◽  
Single Layer ◽  
Side Lobe ◽  
Center Frequency ◽  
Side Lobe Level ◽  
Waveguide Array ◽  
Coupling Mechanism ◽  
Feed Network ◽  
Slotted Waveguide

AbstractIn this paper, two new feed network designs for single layer and double layer slotted waveguide array antennas are presented. A microstrip to substrate integrated waveguide transition is applied to the single layer antenna. The aperture coupling mechanism is used in order to find the optimum feed network for double-layer structure and to obtain stable radiation characteristics over the frequency band. The prototypes of the proposed antennas have been fabricated and tested. The measured results were compared very well with the simulation results obtained from CST microwave studio and showed low side lobe level at the center frequency of 11.5 GHz for the low-profile 4-channel slotted waveguide arrays.

A novel design of ultra-wide stop-band single-layer frequency selective surface using square-loop and cross

2020 ◽  
pp. 1-10
Author(s):  
Amit Birwal ◽  
Sanjeev Singh ◽  
Binod Kumar Kanaujia
Keyword(s):  
Stop Band ◽  
Single Layer ◽  
Frequency Selective Surface ◽  
Transverse Magnetic ◽  
Unit Cell ◽  
Gain Enhancement ◽  
Single Side ◽  
Frequency Selective ◽  
Novel Design ◽  
Excellent Stability

Abstract In this paper, a novel design of ultra-wide stop-band single-side single-layer frequency selective surface (FSS) is presented. The unit cell of the proposed FSS is designed using the combination of conventional square loop and cross (CSLC). To enhance the bandwidth of this structure, an additional cross is inserted in all the four quadrants of CSLC. The stop-band transmission bandwidth assuming −10 dB threshold is found to be 128.94% (2.16–10 GHz) which is 34.33% more as compared to the bandwidth of CSLC. The unit cell with a dimension of 16 × 16 mm2 is printed on one side of an FR4 substrate. The design is fabricated and the measured results are found to be in good agreement with the simulated results. The design provides excellent stability for both transverse magnetic and transverse electric polarizations. The design is very flexible, where any resonant frequency can be achieved by changing the length of unit cell. The design is useful in many applications such as antenna gain enhancement, electromagnetic wave shielding for Wi-Fi/5G systems, and other Internet of Things-based applications.

Single layer miniaturized ultra-thin FSS with five closely spaced bands

2019 ◽  
Vol 11 (08) ◽  
pp. 797-805 ◽  
Author(s):  
Anupam Dey ◽  
Rajarshi Sanyal
Keyword(s):  
Resonant Frequency ◽  
Cell Size ◽  
Cell Structure ◽  
Single Layer ◽  
Frequency Selective Surface ◽  
Unit Cell ◽  
Angular Stability ◽  
Band Frequency ◽  
Unit Cell Size ◽  
Unit Cell Structure

AbstractThis Paper reveals a novel single layer five band frequency selective surface (FSS). Novelties of the proposed FSS lie in its five closely spaced stop bands at 2.4, 3.38, 4.82, 6.32, and 7.75 GHz as well as the reduced single layer structural thickness (0.0016 λ0) and the miniaturized unit cell size (0.0656 λ0) at lower resonant frequency as compared to the existing multiband FSS. The unit cell structure consists of six octagonal concentric interconnected loops. Adjacent loop interconnection technique reduces the cell size by more than 44%. Furthermore, arrow-shaped rings are also introduced on each corner of the outermost octagonal loop, and using this technique approximate 23% cell miniaturization can be achieved. In addition, the proposed FSS exhibits excellent angular stability.

Design and fabrication of miniaturized tri-band frequency selective surface with polarization-independent and angularly stable response

Frequenz ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sayi Soundariya Sampath ◽  
Ramprabhu Sivasamy
Keyword(s):  
Resonance Frequency ◽  
Figure Of Merit ◽  
Close Agreement ◽  
Single Layer ◽  
Frequency Selective Surface ◽  
Unit Cell ◽  
Band Frequency ◽  
Tm Mode ◽  
Frequency Selective ◽  
Polarization Independent

Abstract A single-layer miniaturized tri-band frequency selective surface (FSS) for bandstop filtering applications has been proposed in this work. The metallic layer with four-branched meandered pattern connected in the center is engraved on a dielectric FR-4 substrate. The three stopbands operating at 2.6, 5.6, and 7.1 GHz provides −10 dB bandwidth of 437, 447, and 552 MHz respectively. The size of the unit cell is 0.067 λ∘ × 0.067 λ∘, where λ∘ is the wavelength of the first resonance frequency. As a figure of merit, the symmetric FSS structure provides the advantage of polarization independence. The proposed compact FSS structure exhibits a stable angular response up to 60° in TE and TM mode. Moreover, measurements obtained from the fabricated prototype are compared with the simulated results and are found to be in close agreement.

Polarization-independent single-layer ultra-wideband frequency-selective surface

2015 ◽  
Vol 9 (1) ◽  
pp. 93-97 ◽  
Author(s):  
Ramprabhu Sivasamy ◽  
Balaji Moorthy ◽  
Malathi Kanagasabai ◽  
Jithila V. George ◽  
Livya Lawrance ◽  
...  
Keyword(s):  
Free Space ◽  
Single Layer ◽  
Normal Incidence ◽  
Frequency Selective Surface ◽  
Unit Cell ◽  
Ultra Wideband ◽  
Attenuation Level ◽  
Wide Range ◽  
Frequency Selective ◽  
Polarization Independent

An ultra-wideband (UWB) frequency-selective surface (FSS) exhibiting band rejection characteristic is presented in this paper. The proposed unit cell has the size of 14 × 14 mm2 which is approximately 0.18 × 0.18 λo, where λo corresponds to free space wavelength at the lower cut-off frequency. The proposed UWB FSS consists of a single-layer substrate and provides 20 dB attenuation level for a wide bandwidth of 7.53 GHz at the normal incidence. The proposed FSS is polarization independent and also provides angular-independent operation for the EM wave incidences of 15°, 30° and 45° with 11.5 dB attenuation over a wide range from 4 to 14 GHz.

Miniaturized Band Stop FSS Using Convoluted Swastika Structure

Frequenz ◽  
2017 ◽  
Vol 71 (1-2) ◽  
pp. 51-56 ◽  
Author(s):  
Sridhar Bilvam ◽  
Ramprabhu Sivasamy ◽  
Malathi Kanagasabai ◽  
Gulam Nabi Alsath M ◽  
Sanjay Baisakhiya
Keyword(s):  
Transverse Electric ◽  
Stop Band ◽  
Frequency Selective Surface ◽  
Transverse Magnetic ◽  
Dispersion Analysis ◽  
Unit Cell ◽  
Center Frequency ◽  
Reference Level ◽  
Unit Cell Size ◽  
Identical Response

Abstract This paper presents a miniaturized frequency selective surface (FSS) with stop band characteristics at the resonant frequency of 5.12 GHz. The unit cell size of the proposed FSS design is in the order of 0.095 λ×0.095 λ. The proposed unit cell is obtained by convoluting the arms of the basic swastika structure. The design provides fractional bandwidth of 9.0 % at the center frequency of 5.12 GHz in the 20 dB reference level of insertion loss. The symmetrical aspect of the design delivers identical response for both transverse electric (TE) and transverse magnetic (TM) modes thereby exhibiting polarization independent operation. The miniaturized design provides good angular independency for various incident angles. The dispersion analysis is done to substantiate the band stop operation of the convoluted swastika FSS. The proposed FSS is fabricated and its working is validated through measurements.

scholarly journals Miniaturized Angularly Stable Dual Band Frequency Selective Surface for K and Ka Band

2020 ◽  
pp. 100-103
Author(s):  
Singaram M ◽  
Krishna Kumar E ◽  
Chandraprasad V ◽  
Finney Daniel Shadrach ◽  
Gowthaman Manoharan
Keyword(s):  
Satellite Communication ◽  
Cell Structure ◽  
Single Layer ◽  
Frequency Selective Surface ◽  
Unit Cell ◽  
Dual Band ◽  
Angle Of Incidence ◽  
Band Frequency ◽  
Ka Band ◽  
Frequency Selective

A single layer novel compact frequency selective surface which is used in reflector antenna is designed and simulated. The proposed unit cell reflects electromagnetic waves in K and Ka band with maximum reflection occurring at 22.62 GHz and 35.44 GHz respectively. The designed FSS find its application in satellite communication. A crossed dipole structure in center and two-legged structure in corners with square loop in each quadrant makes the FSS unit cell structure. The FSS is designed with oblique incidence for transverse electric and transverse magnetic polarization with return loss 0.3 dB in 22.62 GHz and less than 0.5 dB in 35.44 GHz. The proposed work shows frequency independence against oblique angle of incidence. The simulated result from CST microwave studio is compared with other similar works.

scholarly journals Dual-Band Single-Layer Fractal Frequency Selective Surface for 5G Applications

Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2880
Author(s):  
Bram Decoster ◽  
Stephanie Maes ◽  
Iñigo Cuiñas ◽  
Manuel García Sánchez ◽  
Rafael Caldeirinha ◽  
...  
Keyword(s):  
Single Layer ◽  
Frequency Selective Surface ◽  
Unit Cell ◽  
Dual Band ◽  
Central Metal ◽  
Fifth Generation ◽  
Measurement Results ◽  
Final Design ◽  
Frequency Selective ◽  
Bow Tie

Due to the global growth in popularity of Fifth Generation (5G) cellular communications, the demand for shielding against it has risen for a variety of applications, mainly related to cybersecurity but also to isolation, calm areas and so on. This research paper aims to provide a suitable dual-band fractal FSS (Frequency Selective Surface) for the 5G lower band frequencies: 750 MHz and 3.5 GHz. The unit cell is in the shape of a bow tie, where each of the triangular parts are Sierpiński triangles. One major addition to the unit cell is a central metal strip to make the manufacturing of the FSS more feasible and to tune the operation frequencies and bandwidths. As with each different stage of a fractal antenna, the different stages of the fractal FSS design behave differently. For this application, stage 2 is sufficient, as we are able to cover frequency bands among those included in the FR1 5G spectrum. Some equations were derived using linear regression in order to provide specific design tools for building an FSS. These equations have high accuracy and can be used to adapt the proposed design to other frequencies. Some other parameters, which are not represented in the aforementioned equations, can also be adjusted for minor tweaking of the final design. This design performs well except under large incidence angles. This should be taken into account when proposing the installation of a structure based on it. A good agreement between simulation and measurement results is observed.

Cracking at the fold in double layer coated paper: the influence of latex and starch composition

TAPPI Journal ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 93-99
Author(s):  
SEYYED MOHAMMAD HASHEMI NAJAFI ◽  
DOUGLAS BOUSFIELD, ◽  
MEHDI TAJVIDI
Keyword(s):  
Mechanical Properties ◽  
Double Layer ◽  
Starch Content ◽  
Single Layer ◽  
Double Layers ◽  
Coated Paper ◽  
Coated Papers ◽  
Coating Layers ◽  
Scanned Images ◽  
Packaging Paper

Cracking at the fold of publication and packaging paper grades is a serious problem that can lead to rejection of product. Recent work has revealed some basic mechanisms and the influence of various parameters on the extent of crack area, but no studies are reported using coating layers with known mechanical properties, especially for double-coated systems. In this study, coating layers with different and known mechanical properties were used to characterize crack formation during folding. The coating formulations were applied on two different basis weight papers, and the coated papers were folded. The binder systems in these formulations were different combinations of a styrene-butadiene latex and mixtures of latex and starch for two different pigment volume concentrations (PVC). Both types of papers were coated with single and double layers. The folded area was scanned with a high-resolution scanner while the samples were kept at their folded angle. The scanned images were analyzed within a constant area. The crack areas were reported for different types of papers, binder system and PVC values. As PVC, starch content, and paper basis weight increased, the crack area increased. Double layer coated papers with high PVC and high starch content at the top layer had more cracks in comparison with a single layer coated paper, but when the PVC of the top layer was low, cracking area decreased. No measurable cracking was observed when the top layer was formulated with a 100% latex layer.

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