Polarization independent bandstop frequency selective surface for X-band application

Circuit World ◽  
2019 ◽  
Vol 46 (1) ◽  
pp. 25-31
Author(s):  
Kanchana D. ◽  
Radha Sankararajan ◽  
Sreeja B.S. ◽  
Manikandan E.

Purpose A novel low profile frequency selective surface (FSS) with a band-stop response at 10 GHz is demonstrated. The purpose of this designed FSS structure is to reject the X-band (8-12 GHz) for the application of shielding. The proposed FSS structure having the unit cell dimension of 8 × 8 mm2, the miniaturization of the FSS unit cell in terms of λ0 is 0.266 λ0 × 0.266 λ0, where λ0 is free space wavelength. The designed FSS provides 4 GHz bandwidth with insertion loss of 15 dB. The transverse electric (TE) and transverse magnetic (TM) modes of the proposed design are same because of polarization independent characteristics and hold the angularly stable frequency response for both TE and TM mode polarization. Both the simulation and measurement results are in good agreement to each other. Design/methodology/approach The proposed FSS design contains square-shaped PEC material, which is placed on the substrate and the shape of the circle and rectangle is etched over the PEC material. The PEC material of the patch dimension is 0.0175 mm. The substrate used for the proposed design is FR4 lossy with the thickness of 0.8 mm and permittivity εr = 4.3 having a loss tangent of 0.02. Findings To find a new design and miniaturized FSS structure is discussed. Originality/value 100%

2015 ◽  
Vol 16 (2) ◽  
pp. 281
Author(s):  
Tariq Rahim ◽  
Jiodong Xu

A low profile multi layer miniaturized unit cell frequency selective surface (FSS) with second-order band-pass response is design. The metallic layers in the form of capacitive patches and inductive grids are separated by dielectric substrates. The non-resonant sub-wavelength unit cells with unit cell dimensions and periodicities on the order of 0.15λ. The overall thickness of approximately 0.03λ is designed which is useful at lower frequencies with long wavelengths. The FSS exhibit a stable frequency response to different angles of incidence and polarizations. The analysis and synthesis of the FSS is done using equivalent circuit method and simulated using CST microwave studio at X-band.


Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 476
Author(s):  
Umer Farooq ◽  
Adnan Iftikhar ◽  
Muhammad Farhan Shafique ◽  
Muhammad Saeed Khan ◽  
Adnan Fida ◽  
...  

This paper presents a highly compact frequency-selective surface (FSS) that has the potential to switch between the X-band (8 GHz–12 GHz) and C-band (4 GHz–8 GHz) for RF shielding applications. The proposed FSS is composed of a square conducting loop with inward-extended arms loaded with curved extensions. The symmetric geometry allows the RF shield to perform equally for transverse electric (TE), transverse magnetic (TM), and 45° polarizations. The unit cell has a dimension of 0.176 λ0 and has excellent angular stability up to 60°. The resonance mechanism was investigated using equivalent circuit models of the shield. The design of the unit element allowed incorporation of PIN diodes between adjacent elements for switching to a lower C-band spectrum at 6.6 GHz. The biasing network is on the bottom layer of the substrate to avoid effects on the shielding performance. A PIN diode configuration for the switching operation was also proposed. In simulations, the PIN diode model was incorporated to observe the switchable operation. Two prototypes were fabricated, and the switchable operation was demonstrated by etching copper strips on one fabricated prototype between adjacent unit cells (in lieu of PIN diodes) as a proof of the design prototypes. Comparisons among the results confirmed that the design offers high angular stability and excellent performance in both bands.


Author(s):  
Amit Birwal ◽  
Sanjeev Singh ◽  
Binod Kumar Kanaujia

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.


Frequenz ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sayi Soundariya Sampath ◽  
Ramprabhu Sivasamy

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.


Author(s):  
Ramprabhu Sivasamy ◽  
Balaji Moorthy ◽  
Malathi Kanagasabai ◽  
Jithila V. George ◽  
Livya Lawrance ◽  
...  

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.


Author(s):  
Durai Kanchana ◽  
Sankararajan Radha ◽  
Balakrishnapillai Suseela Sreeja ◽  
Esakkimuthu Manikandan

Abstract In this paper, a novel miniaturized and flexible dual band frequency selective surface (FSS) is presented. This FSS provides effective shielding in X-band and Ku- band, with a frequency response of 9.4 and 16.7 GHz, respectively. The proposed FSS provides 924 MHz bandwidth at X-band and 1.34 GHz bandwidth at Ku-band with an insertion loss of 20 dB. Moreover, the proposed design is polarization-independent and it provides stable frequency response at various angles of incidences for both transverse electric and transverse magnetic modes. More significantly, the proposed FSS analyzed the bandstop response of the selective frequency and also is suitable for conformal applications. A prototype of the proposed FSS is fabricated. The measured results and simulated results are good in agreement.


Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2880
Author(s):  
Bram Decoster ◽  
Stephanie Maes ◽  
Iñigo Cuiñas ◽  
Manuel García Sánchez ◽  
Rafael Caldeirinha ◽  
...  

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.


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