A study on coaxial line excited monopole probes for in situ permittivity measurements

1987 ◽  
Vol IM-36 (4) ◽  
pp. 1015-1019 ◽  
Author(s):  
Devendra K. Misra
Keyword(s):  
Coaxial Line ◽  
Permittivity Measurements

Non-intrusive in-situ permittivity measurements dedicated to the development of a P and L band dielectric model of wood

2021 ◽  
Author(s):  
F. Demontoux ◽  
M. Gati ◽  
M. el Boudali ◽  
L. Villard ◽  
JP Wigneron ◽  
...  
Keyword(s):  
Dielectric Model ◽  
L Band ◽  
Permittivity Measurements

Permittivity measurements using a coaxial-line conical-tip probe

1997 ◽  
Vol 33 (5) ◽  
pp. 353 ◽  
Author(s):  
R.B. Keam ◽  
J.R. Holdem
Keyword(s):  
Coaxial Line ◽  
Permittivity Measurements

scholarly journals Dielectric characterization of vegetation at L band using an open-ended coaxial probe

2018 ◽  
Vol 7 (3) ◽  
pp. 195-208 ◽  
Author(s):  
Alex Mavrovic ◽  
Alexandre Roy ◽  
Alain Royer ◽  
Bilal Filali ◽  
François Boone ◽  
...  
Keyword(s):  
Black Spruce ◽  
Microwave Remote Sensing ◽  
Dielectric Characterization ◽  
Sensing Applications ◽  
Remote Sensing Applications ◽  
L Band ◽  
Permittivity Measurements ◽  
Coaxial Probe

Abstract. Decoupling the integrated microwave signal originating from soil and vegetation remains a challenge for all microwave remote sensing applications. To improve satellite and airborne microwave data products in forest environments, a precise and reliable estimation of the relative permittivity (ε=ε′-iε′′) of trees is required. We developed an open-ended coaxial probe suitable for in situ permittivity measurements of tree trunks at L-band frequencies (1–2 GHz). The probe is characterized by uncertainty ratios under 3.3 % for a broad range of relative permittivities (unitless), [2–40] for ε′ and [0.1–20] for ε′′. We quantified the complex number describing the permittivity of seven different tree species in both frozen and thawed states: black spruce, larch, red spruce, balsam fir, red pine, aspen and black cherry. Permittivity variability is substantial and can range up to 300 % for certain species. Our results show that the permittivity of wood is linked to the freeze–thaw state of vegetation and that even short winter thaw events can lead to an increase in vegetation permittivity. The open-ended coaxial probe proved to be precise enough to capture the diurnal cycle of water storage inside the trunk for the length of the growing season.

scholarly journals In situ measurement of low-frequency sea-ice dielectric properties and implications for tracking seasonal evolution of microstructure

2016 ◽  
Author(s):  
Megan O'Sadnick ◽  
Malcolm Ingham ◽  
Hajo Eicken ◽  
Erin Pettit
Keyword(s):  
Dielectric Permittivity ◽  
Sea Ice ◽  
Transport Properties ◽  
Pore Volume ◽  
Low Frequency ◽  
Complex Dielectric Permittivity ◽  
Microstructural Characteristics ◽  
Seasonal Evolution ◽  
Permittivity Measurements

Abstract. The seasonal evolution of sea-ice microstructure controls key ice properties, including those governing ocean-atmosphere heat and gas exchange, remote-sensing signatures and the role of the ice cover as a habitat. Non-destructive in situ monitoring of sea-ice microstructure is of value for sea-ice research and operations, but remains elusive to date. We examine the potential for the electric properties of sea ice, which is highly sensitive to the brine distribution within the ice, to serve as a proxy for microstructure and, hence, other ice transport properties. Throughout spring of 2013 and 2014, we measured complex dielectric permittivity in the range of 10 Hz to 95 kHz in landfast ice off the coast of Barrow, Alaska. Temperature and salinity measurements and ice samples provide data to characterize ice microstructure in relation to these permittivity measurements. The results reveal a significant correlation between complex dielectric permittivity, brine volume fraction, and microstructural characteristics including pore volume and connectivity, derived from x-ray microtomography of core samples. The influence of temperature and salinity variations, as well as the relationships between ice properties, microstructural characteristics, and dielectric behavior emerge from multivariate analysis of the combined data set. Our findings suggest some promise for low-frequency permittivity measurements to track seasonal evolution of a combination of mean pore volume, fractional connectivity, and pore surface area-to-volume ratio, which in turn may serve as proxies for key sea-ice transport properties.

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