Open AccessApproaching the lowest operating frequency thickness limits with complex surface impedance of ultrathin absorbers
Author(s) -
Rui Li,
Jianxiong Dong,
Kaixuan Si,
Fan He,
Dace Zha,
Miao Liu,
Shaowei Bie,
Jianjun Jiang
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.416721
Subject(s) - electrical impedance , materials science , microwave , optics , wave impedance , surface (topology) , surface wave , acoustics , high impedance , equivalent circuit , electrical conductor , optoelectronics , physics , electrical engineering , computer science , telecommunications , composite material , engineering , geometry , mathematics , voltage
In this paper, the physical model of electrically thin weakly conductive film with intrinsic surface impedance is established, indicating that the imaginary part of high surface impedance is non-negligible at microwave frequencies. In the design of lossy frequency selective surface absorbers, we introduce the imaginary part of intrinsic surface impedance for the first time. With the experimentally established relationship between the complex surface impedance and the DC square resistance, this complex surface impedance allows us to accurately predict the electromagnetic response of high surface impedance film at microwave frequencies and provides an advantage in reducing the thickness of absorber. The proposed ultra-thin absorber can provide -10 dB reduction over the frequency range of 4.5-13.3 GHz. Total thickness of microwave absorber is only 0.06λ at lowest operating frequency, which is close to the theoretical limitation. The measurement is provided to verify the validity of the equivalent relationship and the reliability of the full-wave model. This study provides a new way to reduce the thickness of absorber, exhibiting promising potential for stealth technique.