A Hybrid Element Triband Frequency Selective Surface With High Angular Stability and Polarization Insensitivity

2020 ◽  
Vol 62 (6) ◽  
pp. 2759-2764
Author(s):  
Gulab Shah ◽  
Qunsheng Cao ◽  
Zain Ul Abidin ◽  
Zubair Rafique
Author(s):  
Alfredo Gomes Neto ◽  
Jefferson Costa e Silva ◽  
Alexandre Jean Rene Serres ◽  
Marina de Oliveira Alencar ◽  
Ianes Barbosa Grecia Coutinho ◽  
...  

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.


Frequenz ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Zain Ul Abidin ◽  
Qunsheng Cao ◽  
Gulab Shah ◽  
Zaheer Ahmed Dayo ◽  
Muhammad Ejaz

Abstract In this paper, a miniaturized bandstop frequency selective surface (FSS) with high angular stability is presented. Each FSS element consists of four sets each consisting eight octagonal concentric interconnected loops. The four sets are connected with each other through outermost octagonal loop. The unit size is miniaturized to 0.066 λ0 at the resonant frequency of 1.79 GHz. The proposed configuration achieves excellent angular stability (only 0.025 GHz resonant frequency deviation is observed upto 83° oblique angles). The working mechanism of FSS is explained with the help of equivalent circuit model (ECM), electric field distribution, and corresponding surface current distribution. A prototype of the designed bandstop FSS is fabricated to verify the simulated frequency response. The experimental results are consistent with the simulation results. Simple geometry, low profile, high angular stability, and compact cell size are prominent features of the proposed structure.


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.


Author(s):  
Nur Biha Binti Mohamed Nafis ◽  
Mohamad Kamal Bin A. Rahim ◽  
Osman Bin Ayop ◽  
Huda Bin A MAjid ◽  
Sunti Tuntrakool

<p>This paper presented the bandstop Koch fractal hexagonal loop frequency selective surface (FSS) for the X-band application. The simulated transmission coefficient response (S_21) had been obtained by using CST software. The proposed Koch fractal hexagonal loop FSS structure is highly insensitive towards angular stability and also incident polarization up to 60 degree , with deviation of resonant frequency,  f_r below than 1%. The parametric analysis on the effect of the periodicity, width, and height of the fractal FSS structure on the S_21 has been illustrated and discussed thoroughly.</p>


IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 123393-123401
Author(s):  
Ning Liu ◽  
Xianjun Sheng ◽  
Chunbo Zhang ◽  
Dongming Guo

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