物理学报2024，Vol.73Issue(2)：109-119,11.DOI:10.7498/aps.73.20231365
抗方阻波动的超宽带轻薄频率选择表面吸波体
Ultra-wideband thin frequency-selective surface absorber against sheet resistance fluctuation
摘要
Abstract
The design of thin frequency selective surface(FSS)absorber based on resistive film that meets the requirements of broadband,polarization independence,incident angle stability,and strong absorption is a challenging task.Fabrication tolerance of resistive film can result in fluctuations in sheet resistance,which negatively affects the absorber performance.To tackle these problems,this work firstly investigates how sheet resistance fluctuations affect the absorbing performance of resistive film FSS absorber.The analysis of simulated surface current density distribution and impedance reveals that the diversity of current paths provides an effective way to mitigate the influence of sheet resistance fluctuation.This is achieved by enabling flexible variation of surface current in response to sheet resistance fluctuations.Consequently,the variation of input impedance of the FSS absorber due to the fluctuation of sheet resistance is suppressed within a small range.Then,a method of extending bandwidth is proposed by employing the complementary variation of FSS impedance with frequency at different layers.By combining this approach with a miniaturization design,a thin and light FSS absorber is developed that exhibits ultra-wide bandwidth,polarization independence and angle stability while mitigating the effects of sheet resistance perturbation.The proposed FSS absorber achieves a 90%absorption bandwidth from 1.50 GHz to 20.50 GHz,covering Ku,X,C,S bands and part of the L and K bands,with a relative bandwidth reaching 173%.The absorber has a thickness of 0.093λL for both transverse electric(TE)polarization and transverse magnetic(TM)polarization,yielding a figure of merit(FoM,the ratio of the theoretical minimum thickness to the actual thickness)of 0.95,indicating that the thickness is close to the theoretical limit.The absorber maintains over 90%absorption rate for TM polarization at an incidence angle of up to 70°,and 80%absorption for TE polarization at 45°.Furthermore,the 90%absorbance bandwidth of the absorber remains at 167.0%when the sheet resistance of any FSS layer fluctuates within a range from 12 to 30 Ω/sq.A prototype of the proposed FSS absorber is fabricated and measured,and the experimental results are in good agreement with the simulation results,thus validating the effectiveness of the proposed method.关键词
频率选择表面/吸波体/薄型/超宽带/方阻波动Key words
frequency selective surface/absorber/thin/ultra-wideband/sheet resistance fluctuation引用本文复制引用
王东俊,孙子涵,张袁,唐莉,闫丽萍..抗方阻波动的超宽带轻薄频率选择表面吸波体[J].物理学报,2024,73(2):109-119,11.基金项目
国家自然科学基金区域创新发展联合基金(批准号:U22A2015)资助的课题. Project supported by the National Natural Science Foundation of China(Grant No.U22A2015). （批准号:U22A2015）
