The investigation of the possibility of using linear dipole antennas for dimension of dielectric permittivity of the real soil and layered soil

Author(s):  
B. I. Avdochenko ◽  
A. P. Batsula ◽  
A. S. Shostak ◽  
S. G. Kataev ◽  
K. A. Volegov
Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2549
Author(s):  
José R. Reyes-Ayona ◽  
Eloisa Gallegos-Arellano ◽  
Juan M. Sierra-Hernández

A moisture sensor based on a composite resonator is used to measure different honey samples, which include imitation honey. The sensor changes its frequency response in accordance with the dielectric permittivity that it detects in the measured samples. Although reflectometry sensors have been used to measure the percentage of moisture in honey for almost a century, counterfeiters have achieved that their apocryphal product is capable of deceiving these kinds of sensors. Metamaterial features of the composite resonators are expected to improve their response when detecting lossy samples such as organic samples. It is also sought that these sensors manage to detect small differences not only in the real parts of the dielectric permitivities of samples but also in their imaginary parts, and, thus, the sensors are able to discern between real honey and slightly altered honey. Effectively, not only was it possible to improve the response of the sensors by using lossy samples but it was also possible to identify counterfeit honey.


1984 ◽  
Vol 32 (2) ◽  
pp. 133-140 ◽  
Author(s):  
M. Sato ◽  
M. Iguchi ◽  
R. Sato

Author(s):  
A. P. Iliopoulos ◽  
B. D. Graber ◽  
J. G. Michopoulos ◽  
J. C. Steuben ◽  
A. J. Birnbaum ◽  
...  

Abstract The microwave sintering of ceramics and other materials has emerged as an attractive method of manufacturing solid objects though volumetric approaches. The accurate modeling of such processes requires the knowledge of the dielectric constant, and particularly the real and imaginary parts of the permittivity, of these materials as they vary with temperature. This particular measurement becomes very challenging as the temperature rises. In this work, an experimental apparatus and an inverse approach are proposed, based on the coupling of the thermo-mechano-electromagnetic physics that can be used to measure the real and imaginary parts of the dielectric constant at high temperatures.


Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1058 ◽  
Author(s):  
R. Mansour ◽  
S. Rioual ◽  
B. Lescop ◽  
P. Talbot ◽  
M. Abboud ◽  
...  

In this study, a sensor based on the development of a planar antenna immersed in sediments dedicated to water content monitoring in this type of material is proposed and experimentally validated. It is produced by a conventional Printed Circuit Board (PCB) manufacturing process on a double-sided metalized FR4 substrate. The sensitivity of the sensor is ensured by the variation of the real part of the complex dielectric permittivity of sediments with water content at around 1 GHz. As shown, in this frequency range, electrode polarization and Maxwell–Wagner polarization effects become negligible, leading to only a bulk water polarization sensitivity. The sensor operates in the reflection mode by monitoring the variation of the resonant frequency as a function of the sediment density through the S11 reflection measurements. An experimental sensitivity of 820   MHz . g − 1 . cm 3 was achieved. Despite the simplification of data interpretation at the considered frequency, the influence of ionic species such as NaCl in sediments on the real part of the relative complex dielectric permittivity is highlighted. This demonstrates the importance of considering a second parameter such as the S11 level at low frequency or the electrical conductivity to extract the density from the frequency measurements.


Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1646 ◽  
Author(s):  
Justyna Szerement ◽  
Aleksandra Woszczyk ◽  
Agnieszka Szypłowska ◽  
Marcin Kafarski ◽  
Arkadiusz Lewandowski ◽  
...  

This paper presents a novel seven-rod sensor used for time-domain reflectometry (TDR) and frequency-domain reflectometry (FDR) measurements of soil water content in a well-defined sample volume. The probe directly measures the complex dielectric permittivity spectrum and for this purpose requires three calibration media: air, water, and ethanol. Firstly, electromagnetic simulations were used to study the influence of the diameter of a container on the sensitivity zone of the probe with respect to the measured calibration media and isopropanol as a verification liquid. Next, the probe was tested in three soils—sandy loam and two silt loams—with six water contents from air-dry to saturation. The conversion from S 11 parameters to complex dielectric permittivity from vector network analyzer (VNA) measurements was obtained using an open-ended liquid procedure. The simulation and measurement results for the real part of the isopropanol dielectric permittivity obtained from four containers with different diameters were in good agreement with literature data up to 200 MHz. The real part of the dielectric permittivity was extracted and related to the moisture of the tested soil samples. Relations between the volumetric water content and the real part of the dielectric permittivity (by FDR) and apparent dielectric permittivity (by TDR) were compared with Topp’s equation. It was concluded that the best fit to Topp’s equation was observed in the case of a sandy loam. Data calculated according to the equation proposed by Malicki, Plagge, and Roth gave results closer to Topp’s calibration. The obtained results indicated that the seven-rod probe can be used to accurately measure of the dielectric permittivity spectrum in a well-defined sample volume of about 8 cm3 in the frequency range from 20 MHz to 200 MHz.


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