Frequency of resonance of human sweat duct in different modes of operation
Frequency of resonance of human sweat duct in different modes of operation
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DOI：
10.1117/12.2289322
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发表时间：
2018-02
期刊：
影响因子：
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通讯作者：
S. Tripathi;Shogo Takahashi;Kento Kinumura;K. Kawase
中科院分区：
文献类型：
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作者：
S. Tripathi;Shogo Takahashi;Kento Kinumura;K. Kawase
最近，一些研究表明，皮肤中的汗管在太赫兹(THz)波与人类的相互作用中发挥着重要作用。据报道，汗道由于其螺旋结构，起到了低Q因子螺旋天线的作用，并根据其结构参数，如螺旋直径和螺旋长度，在亚太赫兹频率范围内共振。根据天线理论，螺旋天线在两种不同的工作模式下工作，即正常模式和轴向模式，螺旋线的尺寸对谐振频率起着关键作用。因此，我们在这里对一些人的手掌和脚进行了光学相干断层扫描(OCT)，以研究汗管的密度、分布和形态特征。此外，我们还利用太赫兹时域谱计算了人体皮肤的介电特性。根据人体汗管的结构参数及其周围介质的太赫兹介电特性，计算了不同工作模式下汗管的谐振频率，发现汗管在亚太赫兹频率范围内发生共振。我们相信，这些发现将有助于进一步研究太赫兹与皮肤的相互作用，并为人类暴露在这些频率下的电磁波的安全水平提供指南。
Recently, some studies have demonstrated that the sweat ducts present in the skin play a significant role in terahertz (THz) wave interaction with human beings. It was reported that the sweat ducts act as a low-Q-factor helical antenna due to their helical structure, and resonate in the sub-terahertz frequency range according to their structural parameters, such as helix diameter and helix length. According to the antenna theory, a helical antenna resonates in two different modes of operation known as normal mode and axial mode and the dimension of the helix plays a key role to determine the frequency of resonance. Therefore, here we performed the optical coherence tomography (OCT) of number of human subjects on their palm and foot to investigate the density, distribution and morphological features of sweat ducts. Moreover, we calculated the dielectric properties of human skin using terahertz time domain spectroscopy. Based on the structural parameters of human sweat ducts and its THz dielectric properties of surrounding medium, we computed the frequency of resonance of sweat duct in different modes of operation and we found that these ducts resonate in subterahertz frequency region. We believe that these findings will facilitate further investigation of the THz-skin interaction and provide guidelines for safety levels with respect to human exposure to electromagnetic waves at these frequencies.