Measurement of the complex refractive index of concrete at 57.5 GHz

Author

Sato, Katsuyoshi ; Manabe, Takeshi ; Polivka, Jiri ; Ihara, Toshio ; Kasashima, Yoshinori ; Yamaki, Katsunori

Author_Institution

Commun. Res. Lab., Minist. of Posts & Telecommun., Tokyo, Japan

Volume

44

Issue

1

fYear

1996

fDate

1/1/1996 12:00:00 AM

Firstpage

35

Lastpage

40

Abstract

The complex refractive index of concrete is measured at 57.5 GHz by the combined use of free-space reflection and transmission methods. The measured refractive index of the concrete 14 months after concreting was 2.55-j0.084. This index, in particular the imaginary part, is sensitive to the curing time after concreting and the water content. The transmission coefficient of a concrete plate, mainly determined from the imaginary part of the complex refractive index, is less than -20 dB/cm when the concrete is fresh and moist and reaches -9 dB/cm after aging for fourteen months. In contrast, the reflection coefficient of a concrete plate is less dependent on water content

Keywords

ageing; concrete; dielectric materials; dielectric properties; electromagnetic wave reflection; electromagnetic wave transmission; materials properties; millimetre wave measurement; millimetre wave propagation; refractive index; 57.5 GHz; EHF; aging; complex refractive index; concrete; concrete plate; curing time; free-space reflection; free-space transmission; reflection coefficient; transmission coefficient; water content; Aging; Building materials; Concrete; Dielectrics; Millimeter wave measurements; Millimeter wave propagation; Millimeter wave radar; Millimeter wave technology; Optical reflection; Refractive index;

fLanguage

English

Journal_Title

Antennas and Propagation, IEEE Transactions on

Publisher

ieee

ISSN

0018-926X

Type

jour

DOI

10.1109/8.477526

Filename

477526