<p>This study aims to identify the electromagnetic wave conduction capability of steel-fiber reinforced C-30/37 concrete and autoclaved aerated (or foamed) concrete, which are commonly used in Türkiye, for the <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(400\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>400</mn> </mrow> </math></EquationSource> </InlineEquation> to <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(2400\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>2400</mn> </mrow> </math></EquationSource> </InlineEquation> MHz band to make provisions for penetration depth at these frequency ranges. Transmission-only <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\({\text{S}}_{21}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mtext>S</mtext> <mn>21</mn> </msub> </math></EquationSource> </InlineEquation> measurement results in free-space are presented for different material thicknesses. Multipath propagation effects are mitigated using an accurate gating scheme in the time domain. Two characterization techniques are proposed: direct attenuation estimation from the measured data and complex permittivity estimation using low-loss dielectric approximation. Both techniques yield almost identical attenuation results, showing a significant variation over the studied frequency band. Results indicate that signal attenuation ranges from <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(26\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>26</mn> </mrow> </math></EquationSource> </InlineEquation> dB/m at <InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(400\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>400</mn> </mrow> </math></EquationSource> </InlineEquation> MHz to <InlineEquation ID="IEq6"> <EquationSource Format="TEX">\(66\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>66</mn> </mrow> </math></EquationSource> </InlineEquation> dB/m at <InlineEquation ID="IEq7"> <EquationSource Format="TEX">\(2400\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>2400</mn> </mrow> </math></EquationSource> </InlineEquation> MHz for C-30/37 concrete whereas these numbers are measured as <InlineEquation ID="IEq8"> <EquationSource Format="TEX">\(33\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>33</mn> </mrow> </math></EquationSource> </InlineEquation> dB/m at <InlineEquation ID="IEq9"> <EquationSource Format="TEX">\(400\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>400</mn> </mrow> </math></EquationSource> </InlineEquation> MHz and <InlineEquation ID="IEq10"> <EquationSource Format="TEX">\(58\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>58</mn> </mrow> </math></EquationSource> </InlineEquation> dB/m at <InlineEquation ID="IEq11"> <EquationSource Format="TEX">\(2400\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>2400</mn> </mrow> </math></EquationSource> </InlineEquation> MHz for aerated concrete. Proposed analysis methods can be quantitatively very useful and employed accurately, especially for determining and estimating the dielectric and conductive parameters of any homogeneous material. Based on these findings, the results of power budget analyses and exemplary radar experiments are presented and evaluated to determine the limits of the applicability of detecting and locating a living person behind such materials.</p>

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Electromagnetic Transmission Characteristics of Some Concrete Materials Commonly Used in Türkiye at Lower Microwave Frequencies

  • Şevket Demirci,
  • Hakan Işıker,
  • Betül Yılmaz,
  • Caner Özdemir

摘要

This study aims to identify the electromagnetic wave conduction capability of steel-fiber reinforced C-30/37 concrete and autoclaved aerated (or foamed) concrete, which are commonly used in Türkiye, for the \(400\) 400 to \(2400\) 2400 MHz band to make provisions for penetration depth at these frequency ranges. Transmission-only \({\text{S}}_{21}\) S 21 measurement results in free-space are presented for different material thicknesses. Multipath propagation effects are mitigated using an accurate gating scheme in the time domain. Two characterization techniques are proposed: direct attenuation estimation from the measured data and complex permittivity estimation using low-loss dielectric approximation. Both techniques yield almost identical attenuation results, showing a significant variation over the studied frequency band. Results indicate that signal attenuation ranges from \(26\) 26 dB/m at \(400\) 400 MHz to \(66\) 66 dB/m at \(2400\) 2400 MHz for C-30/37 concrete whereas these numbers are measured as \(33\) 33 dB/m at \(400\) 400 MHz and \(58\) 58 dB/m at \(2400\) 2400 MHz for aerated concrete. Proposed analysis methods can be quantitatively very useful and employed accurately, especially for determining and estimating the dielectric and conductive parameters of any homogeneous material. Based on these findings, the results of power budget analyses and exemplary radar experiments are presented and evaluated to determine the limits of the applicability of detecting and locating a living person behind such materials.