Electrical Characterization of Glycerin: Water Mixtures: Implications for Use as a Coupling Medium in Microwave Tomography.
Electrical Characterization of Glycerin: Water Mixtures: Implications for Use as a Coupling Medium in Microwave Tomography.
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DOI：
10.1109/tmtt.2016.2638423
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发表时间：
2017-05
影响因子：
4.3
通讯作者：
Paulsen KD
中科院分区：
文献类型：
--
作者：
Meaney PM;Fox CJ;Geimer SD;Paulsen KD
我们研究了在0.1 - 25.0 GHz的频率范围内的甘油和水的混合物的复杂的电性能的宽带行为，特别是因为它们涉及到使用这些液体作为耦合介质的微波断层成像。它们的组合是独特的，因为它们在整个浓度范围内是相互混溶的，这使得它们能够被定制为与生物组织相匹配的介电性质。虽然所得的混合物性质部分地由每种成分的固有低频介电常数的差异驱动，但弛豫频移在增加介电常数色散方面起着不成比例的更大作用，同时还显著增加了1至3 GHz频率范围内的有效电导率。对于整个范围的混合比，弛豫频率从0%甘油的17.5 GHz移动到100%甘油的小于0.1 GHz。特别令人感兴趣的是，对于我们用于微波乳房断层扫描的甘油混合比（70-90%甘油），在1- 3GHz范围内电导率保持在1.0S/m以上。高水平的衰减对于抑制不需要的多径信号是至关重要的。本文提出了一个完整的表征，这些液体沿着与讨论他们的好处和局限性的背景下，微波层析成像。
We examine the broadband behavior of complex electrical properties of glycerin and water mixtures over the frequency range of 0.1 – 25.0 GHz, especially as they relate to using these liquids as coupling media for microwave tomographic imaging. Their combination is unique in that they are mutually miscible over the full range of concentrations which allows them to be tailored to dielectric property matching for biological tissues. While the resultant mixture properties are partially driven by differences in the inherent low frequency permittivity of each constituent, relaxation frequency shifts play a disproportionately larger role in increasing the permittivity dispersion while also dramatically increasing the effective conductivity over the frequency range of 1 to 3 GHz. For the full range of mixture ratios, the relaxation frequency shifts from 17.5 GHz for 0% glycerin to less than 0.1 GHz for 100% glycerin. Of particular interest is the fact that the conductivity stays above 1.0 S/m over the 1–3 GHz range for glycerin mixture ratios (70–90% glycerin) we use for microwave breast tomography. The high level of attenuation is critical for suppressing unwanted multipath signals. This paper presents a full characterization of these liquids along with a discussion of their benefits and limitations in the context of microwave tomography.