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Influence of water absorption on high‐frequency characteristics of insulation layers of printed circuit boards
Author(s) -
Fukunaga Kaori,
Kurahashi Shinji
Publication year - 2007
Publication title -
ieej transactions on electrical and electronic engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.254
H-Index - 30
eISSN - 1931-4981
pISSN - 1931-4973
DOI - 10.1002/tee.20214
Subject(s) - materials science , dielectric , printed circuit board , permittivity , absorption of water , composite material , dielectric loss , absorption (acoustics) , relative permittivity , equivalent circuit , humidity , relative humidity , polyimide , electronic engineering , electrical engineering , optoelectronics , thermodynamics , engineering , layer (electronics) , physics , voltage
The influence of water absorption on complex permittivities of various insulating materials used for printed circuit boards was investigated in the frequency range of K‐band (18–26 GHz). Experimental results revealed that the influence of water absorption on complex permittivity, the dielectric loss factor tanδ, in particular, was considerably high. For example, the dielectric loss of polyimide film at 85°C, 85% RH became 10 times larger than that at room temperature and humidity. Since the complex permittivities, however, retained the initial values when the specimens are dried, the water in the specimen should exist freely at the internal interfaces of the materials. The increase of permittivity directly affects the performance of printed circuit boards at high frequencies, so that it is important to clarify the influence of water on dielectric properties of insulations. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.