Thin Sample Time Domain Reflectometry for Nonideal Dielectrics

1974 ◽  
Vol 52 (24) ◽  
pp. 2463-2468 ◽  
Author(s):  
B. E. Springett ◽  
T. K. Bose
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Rise Time ◽  
Relaxation Times ◽  
Coaxial Line ◽  
Time Domain Reflectometry ◽  
Time Response ◽  
Thin Sample ◽  
Applied Pulse ◽  
Sample Time

The theoretical time response is derived for a pulse reflected from a thin sample of dielectric situated in a coaxial line. The dielectric is assumed to have a distribution of relaxation times. Specific account is taken of the finite rise time of the applied pulse. The equations developed are general and permit the interpretation of measurements without the necessity of transforming to the frequency domain. Explicit equations are developed for the Cole-Davidson and Cole-Cole representations of nonideal dielectrics. Some experimental examples are discussed to assess the utility of the technique.

Frequency analysis of time‐domain reflectometry (TDR) with application to dielectric spectroscopy of soil constituents

Geophysics ◽  
1999 ◽  
Vol 64 (3) ◽  
pp. 707-718 ◽  
Author(s):  
Richard Friel ◽  
Dani Or
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Frequency Domain ◽  
Time Domain ◽  
Dominant Role ◽  
Primary Objective ◽  
Time Domain Reflectometry ◽  
Complete Picture ◽  
Frequency Dependent ◽  
Additional Information

Standard analyses of time‐domain reflectometry (TDR) waveforms in environmental sciences use traveltime along waveguides and reflection amplitude to infer water content and bulk electrical conductivity, respectively. TDR waveforms contain additional information on the frequency‐dependent dielectric permittivity of media, which can be extracted through transformation of TDR waveforms into the frequency domain. The primary objective of this study was to provide a more complete picture of TDR responses in the frequency domain and to improve estimation of dielectric properties. The frequency content of TDR waveforms interacting with various constituents was measured and compared with predictions based on known dielectric properties and waveguide geometries. The study highlights the dominant role of the S11 scatter function, which describes how a TDR signal is modified by media properties and probe configuration. Scatter functions derived from transformed TDR waveforms into the frequency domain were used for estimation of frequency‐dependent dielectric properties of wet soils. The main results were (1) a more complete picture of TDR waveforms in the frequency domain; (2) estimation and use of scatter functions for TDR‐based dielectric permittivity estimation; and (3) highlights of potential usefulness and limitations of a commonly used TDR cable tester (Tektronix 1502B) and waveguide design for estimation of frequency‐dependent dielectric properties of porous media.

Time domain reflectometry of glass beads/magnetite mixtures: A time and frequency domain study

2005 ◽  
Vol 86 (22) ◽  
pp. 224102 ◽  
Author(s):  
Elisabetta Mattei ◽  
Alberto De Santis ◽  
Andrea Di Matteo ◽  
Elena Pettinelli ◽  
Giuliano Vannaroni
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Time Domain Reflectometry ◽  
Glass Beads

scholarly journals A Novel Method for the Accurate Measurement of Soil Infiltration Line by Portable Vector Network Analyzer

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7201
Author(s):  
Xiaobin Li ◽  
Zhengguang Liu ◽  
Lei Lin ◽  
Hao Fan ◽  
Xingyu Liang ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
High Accuracy ◽  
Time Domain Reflectometry ◽  
Network Analyzer ◽  
Complex Dynamic ◽  
Soil Infiltration ◽  
Line Measurement ◽  
Novel Method ◽  
The Time Domain

Accurate measurement of soil infiltration lines is very important for agricultural irrigation systems. It can help monitor the irrigation of soil to control irrigation amounts and promote crop growth. The soil infiltration line is a complex dynamic boundary and is difficult to model accurately, leading to estimation deviation. A traditional TDR (time domain reflectometry) method is used in soil infiltration line measurement, but it lacks good applicability and accuracy. In this paper, we proposed a method—VFTT (The vector network analyzer’s frequency domain signals are converted to the time domain)—by the time domain to frequency domain conversion principle to improve the accuracy of soil infiltration line measurement. The experiment results show that the measurement method of soil infiltration line based on VFTT has high accuracy and robustness. After fitting the measured value with the actual one, R2 reaching more than 0.98 can effectively measure the position of the soil infiltration line.

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