煤岩介质在太赫兹频段的介电特性研究  

Study of dielectric property of coal and rock medium in Terahertz domain

作　　者：王昕[1] 苗曙光[1] 丁恩杰[1] 

机构地区：[1]中国矿业大学物联网(感知矿山)研究中心,信息与电气工程学院,江苏徐州221116

出　　处：《中国矿业大学学报》2016年第4期739-746,共8页Journal of China University of Mining & Technology

基　　金：国家重点基础研究发展计划(973)项目(2014CB046300)

摘　　要：为了研究煤岩介质在太赫兹频段下的介电特性,采用太赫兹时域光谱技术对煤岩介质进行了测试.研究了基于平面煤层模型的煤岩介质吸收系数、折射率、复介电常数和复电导率等物理参数随频率变化的关系,认为在太赫兹频段,岩壁的反射特性、电磁波的勘探能力以及其在井下的传播特性将发生较大改变.结果表明:当样本厚度为3mm时,煤岩太赫兹频谱的有效带宽分别为1.2THz和1.4THz.在有效带宽范围内,煤岩介质呈现出高衰减性,无明显吸收峰,其折射率、复介电常数、电导率实部和损耗角正切无较大变化.将上述数据与兆赫兹频段的煤岩电参数进行比较,岩的介电常数、煤岩的电导率和衰减系数发生了较大变化.运用德拜模型对实验数据进行验证和解释,在3阶德拜模型下,计算值可以很好的与理论值相吻合.The terahertz time domain spectroscopy （THz-TDS） was used as a tool to study the dielectric property of coal and rock in terahertz domain. The relationships between frequency and physical parameters of coal and rock such as absorption coefficient, refractive rate, complex permittivity and complex conductivity were studied through flat coal seam model. It is found that the reflection characteristics of rock, the detection ability and the propagation characteristics of electromagnetic wave in mine would change greatly in THz. The results show that the effective bandwidth of coal and rock is 1.2 THz and 1.4 THz respectively, when the thickness of sample is 3mm. In the effective bandwidth, the physical characteristics of coal and rock such as the high attenuation and no absorption peak has been found. What＇s more, there are no obvious changes in dielectric constant, refractive index, real part of conductivity and the loss tangent. Compared with the dielectric property of coal and rock in MHz, there are great changes in the dielectric constant of rock, conductivity and attenuation coefficient of coal and rock. The Debye model was used for experimental data validation and interpretation. As a result, the experimental data can well fit the theoretical data in the third order Debye model.

关 键 词：太赫兹时域光谱 煤岩介质 介电特性 德拜模型 

分 类 号：O441.6[理学—电磁学]