scholarly journals Complementary frequency selective surface pair-based intelligent spatial filters for 5G wireless systems

2021 ◽  
Vol 30 (1) ◽  
pp. 1054-1069
Author(s):  
Ankush Kapoor ◽  
Ranjan Mishra ◽  
Pradeep Kumar

Abstract Frequency selective surface (FSS)-based intelligent spatial filters are capturing the eyes of the researchers by offering a dynamic behavior when exposed to the electromagnetic radiations. In this manuscript, a concept of creating complementary structures which stems from Babinet’s principle is illustrated. A hybrid complementary pair of FSS (CPFSS) comprising double square loop FSS (DSLFSS) and double square slot FSS (DSSFSS) on either side of the dielectric substrate is proposed. DSLFSS offers band-pass behavior and can be placed as a superstrate, whereas DSSFSS behaves as a band-stop intelligent spatial filter that blocks the radiations falling on it, thus making them applicable for use as a substrate. The technique utilized for analyzing DSLFSS and DSSFSS structures is based on the equivalent circuit modeling and transmission line methodology. The CPFSS structure offers the design simplicity, hence, suitable for placing them with the printed patch antenna radiators in wireless networking devices operating in sub-6 GHz 5G spectrum. DSLFSS offers band-pass behavior ranging from 2.99 to 5.56 GHz, whereas DSSFSS offers band-stop behavior ranging from 2.85 to 5.42 GHz covering all n77 (3.3–4.2 GHz), n78 (3.3–3.8 GHz), and n79 (4.4–5 GHz) bands of FR1 spectrum of sub-6 GHz 5G range. The passband and the stopband offered by the two structures of CPFSS geometry are stable to oblique angles of incidence and the proposed design also offers polarization-independent behavior. The thickness of the dielectric region existing within the pair of designed structures is critical for the location of the passbands and the stopbands. The impact of the overall thickness of the dielectric substrate on the passbands and stopbands is also reported in this article.

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
In-Gon Lee ◽  
Ic-Pyo Hong

A band-stop scalable frequency selective surface (FSS) structure that provides stability for an angle of incidence and polarization is designed using the repetitive arrangement of a unit structure miniaturized on a thin dielectric substrate. The designed miniaturized FSS has a hexagonal unit cell of a minimum size of 0.081 λat 2.5 GHz in which a triangular loop is repeated. In addition to the frequency stability, the proposed structure reduces the design complexity that is the biggest shortcoming of the miniaturization techniques studied previously. A scalable FSS structure possessing stable frequency response characteristics over a wide band ranging from 2 to 8 GHz, which is achieved by the control of a single design variable, can be designed. For verification of the proposed structure, FSS structures that operate in the bands of 2.5 GHz, 5 GHz, and 8.2 GHz have been designed and fabricated on a very thin substrate. It has been confirmed that the results of the measurement and simulation correspond well with each other. The designed structures also demonstrate high stability for both the polarized wave and the incidence angle of the incident wave.


Author(s):  
Alfredo Gomes Neto ◽  
Jefferson Costa e Silva ◽  
Alexandre Jean Rene Serres ◽  
Marina de Oliveira Alencar ◽  
Ianes Barbosa Grecia Coutinho ◽  
...  

2019 ◽  
Vol 11 (3) ◽  
pp. 255-267 ◽  
Author(s):  
Krushna Kanth Varikuntla ◽  
Raghavan Singaravelu

AbstractIn this paper, the patch-type frequency selective surfaces (FSS) based on substrate-integrated waveguide (SIW) technology is proposed to improve the bandwidth (BW) and angular performance. The proposed FSS configuration overcomes the limitations of both conventional 2D and 3D FSS structures. A closely coupled cascaded mechanism is employed to combine two identical FSS elements separated by thin dielectric substrate results in incorporation of SIW technology; hence, named as 2.5D FSS. A derived equivalent circuit model is used to estimate the basic performance of proposed FSS–SIW elements, and the response of analytical expressions has been validated and final design is obtained using full-wave simulations. Two basic FSS elements viz. single square loop and a Jerusalem cross have been investigated to prove the enhancement in their BW and angular stability. The proposed technique evidently improves the BW and angular stability of FSS structures than in its established form. Besides, various important parameters that influence the performance characteristics of reported 2.5D FSSs are also studied. The important observations made on the thickness, as the thickness increases the bandstop FSS, can change to bandpass FSS. Finally, the proposed FSS structure has been fabricated and measured using free space measurement setup, to show the effectiveness of theoretical results. The measured results show good agreement with simulated results at normal and oblique incidence angle.


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.


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