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An experimental study on wideband wave absorber using periodically‐arranged short carbon fibers
Author(s) -
Doi Toru,
Hashimoto Osamu,
Tanaka Takao,
Umemura Ichiro
Publication year - 2010
Publication title -
electronics and communications in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.131
H-Index - 13
eISSN - 1942-9541
pISSN - 1942-9533
DOI - 10.1002/ecj.10209
Subject(s) - wideband , absorption (acoustics) , materials science , carbon fibers , optics , electrical impedance , composite material , physics , engineering , composite number , electrical engineering
This paper examines λ/4 type wave absorbers using periodically‐arranged short carbon fibers whose length is λ/2 or λ/4 for two arbitrary frequencies. Measurements on these wave absorbers show wideband absorption characteristics of about 20 dB from 4 to 7 GHz, and the thickness of the absorbers is 34% that of traditional λ/4 wave absorbers at 4.5 GHz. We also estimated the surface resistance of the aspect‐arranged short carbon fibers to support the theoretical design of the absorber, and agreement of the calculated and measured absorption characteristics of the wave absorbers was obtained. Then, for various thicknesses and materials of the spacer, we calculated the absorption characteristics by using the estimated surface impedance. The calculated spacer thickness was smaller and the absorption characteristic was wider than the measured values. The results show that the design of wave absorbers using periodically‐arranged short carbon filters is theoretically possible. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(3): 16–23, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/ecj.10209