Choudhary Vipin, Rönnow Daniel
University of Gävle, Department of Electrical Engineering, Mathematics and Science, 801 76 Gävle, Sweden.
KTH Royal Insitute of Technology, Technical Information Science, 114 28 Stockholm, Sweden.
Sensors (Basel). 2020 Jun 2;20(11):3161. doi: 10.3390/s20113161.
An ultra-wide band radar reflection measurement technique for industrial applications is introduced. A new method for determining the complex refractive index (or equivalently the relative permittivity) of objects with planar interfaces is presented. The object thickness can also be obtained experimentally. The method is a combination of time and frequency domain techniques. The objects can be finite in size and at a finite distance. The limits in size and distance for the method to be valid are experimentally investigated. The method is relatively insensitive to hardware impairments such as frequency dependence of antennas and analog front end. The method is designed for industrial in-line measurements on objects on conveyor belts. Results are presented for solid wood and wood chips; the complex refractive index is determined in the frequency range 0.5 to 2.0 GHz for the moisture content of 3.6-10% for solid wood and 30-50% for wood chips. Polarimetric measurements are used; wood and wood chips are anisotropic.
介绍了一种用于工业应用的超宽带雷达反射测量技术。提出了一种确定具有平面界面物体的复折射率（或等效相对介电常数）的新方法。物体厚度也可通过实验获得。该方法是时域和频域技术的结合。物体可以是有限尺寸且处于有限距离。通过实验研究了该方法有效的尺寸和距离限制。该方法对诸如天线频率依赖性和模拟前端等硬件损伤相对不敏感。该方法设计用于对传送带上的物体进行工业在线测量。给出了实木和木屑的测量结果；对于实木，在0.5至2.0 GHz频率范围内，针对3.6 - 10%的含水量确定了复折射率，对于木屑，含水量为30 - 50%时确定了复折射率。使用了极化测量；木材和木屑是各向异性的。
