scholarly journals Design of a Tunable Absorber Based on Active Frequency-Selective Surface for UHF Applications

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3989
Author(s):  
Kainan Qi ◽  
Liangsheng Li ◽  
Jianxun Su ◽  
Yongqiang Liu ◽  
Junwen Chen
Keyword(s):  
Layer Structure ◽  
Single Layer ◽  
Frequency Selective Surface ◽  
Dielectric Substrate ◽  
Reverse Bias Voltage ◽  
Resistive Layer ◽  
Density Distributions ◽  
Tunable Absorber ◽  
Frequency Selective ◽  
Foam Thickness

An ultrathin tunable absorber for the ultrahigh frequency (UHF) band is presented in this paper. The absorber is a single-layer structure based on the topology of a Salisbury screen, in which the conventional resistive layer is replaced by an active frequency-selective surface (AFSS) loaded with resistors and varactors. The reflectivity response of the absorber can be controlled by adjusting the reverse bias voltage for the varactors, which is verified by both simulated and measured results. The experimental results show that the reflectivity response of the absorber can be modulated below −10 dB over a frequency band ranging from 415 to 822 MHz. The total thickness of the absorber, 10 mm, is equivalent to only λ/72 of the lower limit frequency. The absorbing mechanism for the designed absorber is illustrated by simulating the volume loss density distributions. A detailed analysis is also carried out on the basis of these parameters, such as the AFSS shape, resistor, thickness of the foam, thickness and permittivity of the dielectric substrate, and incident angles, which contribute to the reflectivity of the AFSS absorber.

A Tri-band Angularly Stable Frequency Selective Surface with Controllable Resonances for EM Shielding

Frequenz ◽  
2020 ◽  
Vol 74 (1-2) ◽  
pp. 25-31 ◽  
Author(s):  
Fei Wang
Keyword(s):  
Layer Structure ◽  
Equivalent Circuit Model ◽  
Single Layer ◽  
Frequency Selective Surface ◽  
Electromagnetic Shielding ◽  
Low Profile ◽  
Stable Frequency ◽  
Simulation Results ◽  
Frequency Selective ◽  
The Operating Mechanism

AbstractIn the paper, a tri-band angularly stable frequency selective surface (FSS) with controllable resonances for electromagnetic shielding is proposed. Different from traditional single-layer structure, the FSS proposed is based on cascaded structure that creates three adjustable blocking bands around frequency 5.93 GHz, 7.33 GHz and 9.17 GHz, respectively. The designed FSS has a low profile with thickness of λ0/100, where the λ0 represents wavelength of the first band-stop resonance frequency. Besides, the proposed FSS exhibits stable frequency response up to 70° with respect to different polarizations. Therefore, this FSS is flexible and can be used in electromagnetic shielding field where needs conformal screen. To investigate and understand the operating mechanism better, a equivalent circuit model (ECM) is deduced and given in the Section 2, the calculated results match the full-wave EM simulation results perfectly. Finally, a prototype of this FSS is fabricated and measured, the measurement results are in accordance with the simulation results.

Dual‐band single‐layer quarter ring frequency selective surface for Wi‐Fi applications

2016 ◽  
Vol 10 (4) ◽  
pp. 435-441 ◽  
Author(s):  
David Ferreira ◽  
Iñigo Cuiñas ◽  
Rafael F.S. Caldeirinha ◽  
Telmo R. Fernandes
Keyword(s):  
Single Layer ◽  
Frequency Selective Surface ◽  
Dual Band ◽  
Frequency Selective ◽  
Ring Frequency

Design and implementation of 2.5D frequency-selective surface based on substrate-integrated waveguide technology

2019 ◽  
Vol 11 (3) ◽  
pp. 255-267 ◽  
Author(s):  
Krushna Kanth Varikuntla ◽  
Raghavan Singaravelu
Keyword(s):  
Incidence Angle ◽  
Equivalent Circuit Model ◽  
Frequency Selective Surface ◽  
Dielectric Substrate ◽  
Angular Stability ◽  
Substrate Integrated Waveguide ◽  
Patch Type ◽  
Angular Performance ◽  
Final Design ◽  
Frequency Selective

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.

A Single Layer UWB Frequency Selective Surface for Shielding Application

2020 ◽  
Vol 49 (8) ◽  
pp. 4794-4800
Author(s):  
D. Kanchana ◽  
S. Radha ◽  
B. S. Sreeja ◽  
E. Manikandan
Keyword(s):  
Single Layer ◽  
Frequency Selective Surface ◽  
Frequency Selective

Novel Dual-Band Miniaturized Frequency Selective Surface based on Fractal Structures

Frequenz ◽  
2017 ◽  
Vol 71 (1-2) ◽  
pp. 57-63 ◽  
Author(s):  
Tao Zhong ◽  
Hou Zhang ◽  
Rui Wu ◽  
Xueliang Min
Keyword(s):  
Resonant Frequency ◽  
Free Space ◽  
Single Layer ◽  
Frequency Selective Surface ◽  
Anechoic Chamber ◽  
Dual Band ◽  
Fractal Structures ◽  
Frequency Selective ◽  
Good Agreement

Abstract A novel single-layer dual-band miniaturized frequency selective surface (FSS) based on fractal structures is proposed and analyzed in this paper. A prototype with enough dimensions is fabricated and measured in anechoic chamber, and the measured results provide good agreement with the simulated. The simulations and measurements indicate that the dual-band FSS with bandstop selectivity center at 3.95 GHz and 7.10 GHz, and the whole dimension of the proposed FSS cell is only 7×7 mm2, amount to 0.092λ0×0.092λ0, that λ0 is free space wavelength at first resonant frequency. In addition, the center frequencies have scarcely any changes for different polarizations and incidences. What’s more, dual-band mechanism is analyzed clearly and it provides a new way to design novel miniaturized FSS structures.

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