Open resonator for precision dielectric measurements in the 100 GHz band

Komiyama, Bokuji; Kiyokawa, M.; Matsui, Toshiaki

doi:10.1109/22.88556

Cited by 83 publications

(32 citation statements)

References 11 publications

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“…All our dielectric permittivity measurements were performed in the frequency range of 33-35 GHz and under the temperature range −16 ± 1.5°C at the National Institute of Polar Research (NIPR), Japan. The errors associated with sample thickness variations (<0.1 mm) were minimized by solving equations (Jones, 1976;Komiyama, 1991) for multiple resonant frequencies simultaneously, to find a unique solution of dielectric permittivity with a common sample thickness. The final errors in permittivity and dielectric anisotropy Δε (=ε v − ε h ) were ±0.005 and ±0.001 respectively.…”

Section: Methods Of Measurement and Samplesmentioning

confidence: 99%

Densification of layered firn in the ice sheet at Dome Fuji, Antarctica

et al. 2016

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ABSTRACT. In order to better understand the densification of polar firn, firn cores from the three sites within ∼10 km of Dome Fuji, Antarctica, were investigated using surrogates of density: dielectric permittivities ε v and ε h at microwave frequencies with electrical fields in the vertical and horizontal planes respectively. Dielectric anisotropy Δε (=ε v − ε h ) was then examined as a surrogate of the anisotropic geometry of firn. We find that layered densification is explained as a result of complex effects of two phenomena that commonly occur at the three sites. Basically, layers with initially smaller density and smaller geometrical anisotropy deform preferentially throughout the densification process due to textural effects. Second, layers having a higher concentration of Cl − ions deform preferentially during a limited period from the near surface depths until smoothing out of layered Cl − ions by diffusion. We hypothesize that Cl − ions dissociated from sea salts soften firn due to modulation of dislocation movement. Moreover, firn differs markedly across the three sites in terms of strength of geometrical anisotropy, mean rate of densification and density fluctuation. We hypothesize that these differences are caused by textural effects resulting from differences in depositional conditions within various spatial scales.

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Section: Methods Of Measurement and Samplesmentioning

confidence: 99%

Densification of layered firn in the ice sheet at Dome Fuji, Antarctica

et al. 2016

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“…This method enables precise measurement of the dielectric permittivity tensor and the dielectric anisotropy if appropriate sets of frequency and sample thickness are selected to reduce errors [e.g., Jones, 1976;Komiyama et al, 1991]. Ten samples, a to j, were measured, and are described in Table 2.…”

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confidence: 99%

Metamorphism of stratified firn at Dome Fuji, Antarctica: A mechanism for local insolation modulation of gas transport conditions during bubble close off

et al. 2009

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[1] The evolution of the structure of a 112.59 m long firn core recovered at Dome Fuji, East Antarctica, was investigated in order to improve understanding of firn densification and bubble formation processes, which are important for interpreting local insolation proxies used for astronomical dating of deep ice cores. Using selected samples, we measured physical properties including (1) the relative dielectric permittivities in both the vertical and horizontal planes, (2) the bulk density at a resolution of millimeters, (3) the three-dimensional geometric structure of pore space, and (4) crystal orientation fabrics. We found that the firn at Dome Fuji contains horizontal strata with thicknesses of several centimeters. Near the surface of the ice sheet, these strata are characterized by contrasting bulk density. Earlier field studies suggest that summer insolation causes densification of surface firn. Down to $30 m, density maxima exhibited a clear positive correlation with the strength of structural anisotropy and c axis clustering around the vertical. In contrast, the correlation is negative in deeper firn, confirming previous findings that initially less dense firn became denser than initially dense firn. In addition, numerous examples of textures indicating that deformation preferentially occurred in weaker layers were found. Moreover, the initially dense firn layers were more permeable for air near the bottom of firn. We propose a model linking firn properties with conditions for the gas transport processes near the bottom of firn. The model explains how stronger insolation can lead to bulk ice with a lower O 2 /N 2 ratio and smaller total gas content.Citation: Fujita, S., J. Okuyama, A. Hori, and T. Hondoh (2009), Metamorphism of stratified firn at Dome Fuji, Antarctica: A mechanism for local insolation modulation of gas transport conditions during bubble close off,

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“…Meanwhile, open cavity is also a power tool for measuring accurately complex permittivity of dielectric materials at millimeter and sub-millimeter wavelengths. How to use this technique to measure the complex permittivity of dielectric material accurately have been investigated in detail [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. All of the open cavities investigated are based on spherical mirrors or spherical and planar mirrors.…”

Section: Introductionmentioning

confidence: 99%