• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Measurement Science & Technology >Free-space measurement of dielectric properties of cereal grain and oilseed at microwave frequencies
【24h】

Free-space measurement of dielectric properties of cereal grain and oilseed at microwave frequencies

机译：微波频率下谷物和油料介电特性的自由空间测量

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Principles of dielectric property measurement by microwave free-space transmission measurements are presented, and the important sources of errors in such measurements are discussed. A system, including a vector network analyser, horn/lens antennas, holder for grain and oilseed samples and a radiation absorbing enclosure that was used for such measurements is described, and the techniques and procedures followed to obtain reliable permittivity data for wheat, shelled corn (maize) and soybeans are outlined. Data illustrating linear relationships between microwave attenuation and phase shift per unit sample thickness, each divided by the bulk density of the granular materials, and frequency and moisture content are presented graphically. The linear dependence of calculated permittivity components, dielectric constant and loss factor, on bulk density is also shown, and permittivity components for wheat, corn and soybeans are listed for reference at frequencies from 5 to 17 GHz at different densities and moisture levels at about 23℃. Permittivity values are also listed for the same three commodities, adjusted to a medium density value through use of the Landau and Lifshitz, Looyenga dielectric mixture equation, for the total range of moisture contents at 10 GHz and at the same temperature.
机译：介绍了通过微波自由空间透射测量进行介电性能测量的原理，并讨论了这种测量中的重要误差源。描述了一种系统，包括矢量网络分析仪，喇叭/透镜天线，用于谷物和油料样品的支架以及用于此类测量的辐射吸收外壳，并遵循了以下技术和步骤来获得小麦，带壳玉米的可靠介电常数数据（玉米）和大豆概述。以图形方式显示了数据，该数据说明了微波衰减与每单位样品厚度的相移之间的线性关系，每个线性关系除以颗粒材料的堆积密度，以及频率和水分含量。还显示了计算得出的介电常数，介电常数和损耗因子与体积密度的线性关系，并列出了小麦，玉米和大豆的介电常数，以供参考，其频率为5至17 GHz，且密度和湿度在大约23 ℃。还列出了相同三种商品的介电常数值，通过使用Landau和Lifshitz，Looyenga介电混合方程式，将湿度在10 GHz和相同温度下的总范围调整为中等密度值。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号