Measurement and modeling of the TDR signal propagation through layered dielectric media

Marcel Schaap, D. A. Robinson, S. P. Friedman, A. Lazar

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

Layered dielectric materials are often encountered in the natural environment due to differences in water content caused either by a wetting or drying front. This is especially true for coarse-grained materials such as sandy soils, sediments, and some rocks that have very distinctive layers of water content. This paper examines the issue of how the permittivity along a time domain reflectometry (TDR) probe is averaged as a function of layer thickness and probe orientation. Measurements of apparent permittivity using TDR are presented for two-, three-, and multi-layer materials. Time domain reflectometry waveforms are modeled for multiple layers of varying thickness and show a change in the averaging of the apparent permittivity from refractive index to arithmetic when more thin layers are present. Analysis of the modeled results shows that the averaging regime is frequency-dependent. However, broadband techniques applied to materials with a few layers will generally produce refractive averaging. A transition to arithmetic averaging is found for systems having many (>4 layers). Narrow-band methods may be very sensitive to layering and may perform in a highly non-refractive way when layering with a strong permittivity contrast is present.

Original languageEnglish (US)
Pages (from-to)1113-1121
Number of pages9
JournalSoil Science Society of America Journal
Volume67
Issue number4
StatePublished - Jul 2003
Externally publishedYes

Fingerprint

time domain reflectometry
permittivity
modeling
water content
refractive index
sandy soils
probe
rocks
drying
sediments
wetting
sandy soil
methodology
material
arithmetics
rock
sediment

ASJC Scopus subject areas

  • Soil Science
  • Earth-Surface Processes

Cite this

Measurement and modeling of the TDR signal propagation through layered dielectric media. / Schaap, Marcel; Robinson, D. A.; Friedman, S. P.; Lazar, A.

In: Soil Science Society of America Journal, Vol. 67, No. 4, 07.2003, p. 1113-1121.

Research output: Contribution to journalArticle

Schaap, Marcel ; Robinson, D. A. ; Friedman, S. P. ; Lazar, A. / Measurement and modeling of the TDR signal propagation through layered dielectric media. In: Soil Science Society of America Journal. 2003 ; Vol. 67, No. 4. pp. 1113-1121.
@article{cd38aa735a114df0b9b61ba0be56fc55,
title = "Measurement and modeling of the TDR signal propagation through layered dielectric media",
abstract = "Layered dielectric materials are often encountered in the natural environment due to differences in water content caused either by a wetting or drying front. This is especially true for coarse-grained materials such as sandy soils, sediments, and some rocks that have very distinctive layers of water content. This paper examines the issue of how the permittivity along a time domain reflectometry (TDR) probe is averaged as a function of layer thickness and probe orientation. Measurements of apparent permittivity using TDR are presented for two-, three-, and multi-layer materials. Time domain reflectometry waveforms are modeled for multiple layers of varying thickness and show a change in the averaging of the apparent permittivity from refractive index to arithmetic when more thin layers are present. Analysis of the modeled results shows that the averaging regime is frequency-dependent. However, broadband techniques applied to materials with a few layers will generally produce refractive averaging. A transition to arithmetic averaging is found for systems having many (>4 layers). Narrow-band methods may be very sensitive to layering and may perform in a highly non-refractive way when layering with a strong permittivity contrast is present.",
author = "Marcel Schaap and Robinson, {D. A.} and Friedman, {S. P.} and A. Lazar",
year = "2003",
month = "7",
language = "English (US)",
volume = "67",
pages = "1113--1121",
journal = "Soil Science Society of America Journal",
issn = "0361-5995",
publisher = "Soil Science Society of America",
number = "4",

}

TY - JOUR

T1 - Measurement and modeling of the TDR signal propagation through layered dielectric media

AU - Schaap, Marcel

AU - Robinson, D. A.

AU - Friedman, S. P.

AU - Lazar, A.

PY - 2003/7

Y1 - 2003/7

N2 - Layered dielectric materials are often encountered in the natural environment due to differences in water content caused either by a wetting or drying front. This is especially true for coarse-grained materials such as sandy soils, sediments, and some rocks that have very distinctive layers of water content. This paper examines the issue of how the permittivity along a time domain reflectometry (TDR) probe is averaged as a function of layer thickness and probe orientation. Measurements of apparent permittivity using TDR are presented for two-, three-, and multi-layer materials. Time domain reflectometry waveforms are modeled for multiple layers of varying thickness and show a change in the averaging of the apparent permittivity from refractive index to arithmetic when more thin layers are present. Analysis of the modeled results shows that the averaging regime is frequency-dependent. However, broadband techniques applied to materials with a few layers will generally produce refractive averaging. A transition to arithmetic averaging is found for systems having many (>4 layers). Narrow-band methods may be very sensitive to layering and may perform in a highly non-refractive way when layering with a strong permittivity contrast is present.

AB - Layered dielectric materials are often encountered in the natural environment due to differences in water content caused either by a wetting or drying front. This is especially true for coarse-grained materials such as sandy soils, sediments, and some rocks that have very distinctive layers of water content. This paper examines the issue of how the permittivity along a time domain reflectometry (TDR) probe is averaged as a function of layer thickness and probe orientation. Measurements of apparent permittivity using TDR are presented for two-, three-, and multi-layer materials. Time domain reflectometry waveforms are modeled for multiple layers of varying thickness and show a change in the averaging of the apparent permittivity from refractive index to arithmetic when more thin layers are present. Analysis of the modeled results shows that the averaging regime is frequency-dependent. However, broadband techniques applied to materials with a few layers will generally produce refractive averaging. A transition to arithmetic averaging is found for systems having many (>4 layers). Narrow-band methods may be very sensitive to layering and may perform in a highly non-refractive way when layering with a strong permittivity contrast is present.

UR - http://www.scopus.com/inward/record.url?scp=0043205909&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0043205909&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0043205909

VL - 67

SP - 1113

EP - 1121

JO - Soil Science Society of America Journal

JF - Soil Science Society of America Journal

SN - 0361-5995

IS - 4

ER -