Influence of water content of expanded clay on the reflection coefficient of electromagnetic shild

Abstract

The regularities of the influence of the moisture content of expanded clay on the values of the reflection coefficient of electromagnetic radiation (EMR) of this material in the frequency range of 1–17 GHz have been established. The relationship between the size of fractions (pore size) of expanded clay and the operating frequency range of the EMR screen samples has been determined. It is shown that a twofold increase in the moisture content of expanded clay with fractions of 1…4 and 10…20 mm provides an extension of the operating frequency range of the EMR shield samples made on the basis of this material, with a decrease in the reflection coefficient of the test samples by 1.7 and 3 times, respectively. It was found that an increase in the moisture content of expanded clay from 19 to 40 % with a decrease in the size of its fractions from 10…20 to 1…4 mm and a pore size from 0.1…0.2 to 0.01…0.06 mm provides a decrease in the values of the reflection coefficient of EMR screen samples at frequencies of 7.7–17.0 GHz, and an increase in the size of expanded clay fractions from 1…4 to 10…20 mm with an increase in the size of its pores from 0.01…0.06 to 0.1…0.2 mm provides a decrease in the values of the reflection coefficient of EMR screen samples at frequencies of 1.0–7.7 GHz. It is shown that the practical use of these regularities makes it possible to form EMR screen samples with reflection coefficients from –2.8 to –22.0 dB in the frequency range 1–17 GHz, which makes it possible to recommend them for use when creating shielded rooms.