微波频段下颗粒状农产品的介电特性测量与分析  

Measurement and Analysis of Dielectric Property of Granular Agricultural Products in the Microwave Frequency Band

作　　者：钟汝能[1] 郑勤红[1,2] 姚斌[2] 向泰[1] ZHONG Runeng;ZHENG Qinhong;YAO Bin;XIANG Tai(School of Energy and Environmental Science,Yunnan Normal University,Kunming 650500,China;School of Physics and Electronic Information,Yunnan Normal University,Kunming 650500,China)

机构地区：[1]云南师范大学能源与环境科学学院,昆明650500 [2]云南师范大学物理与电子信息学院,昆明650500

出　　处：《中国农业科技导报》2019年第12期68-75,共8页Journal of Agricultural Science and Technology

基　　金：国家自然科学基金项目(31560305,61961044);云南省科技计划面上项目(2016FB141)

摘　　要：介电特性在农产品微波热加工应用研究中具有重要价值。提出一种基于无校准同轴传输反射法和修正通用有效介质公式(modified general effective medium,MGEM)的农产品介电特性测量方案,以颗粒状农产品为对象,实验测量获得微波频率段内17种菜籽颗粒、杂粮颗粒和草籽颗粒的介电特性数据,对相关关键问题进行了分析和讨论。研究结果表明,该测量方案可用于测量和分析高频波段下颗粒状农产品的介电特性;室温下颗粒状农产品的介电特性与微波频率、含水(油)率之间具有相互依存关系,且满足相应的关系方程;在民用微波频率2.45 GHz和含水率M6(2%,25%)条件下,不同种类颗粒状农产品的介电常数介于3.5-9.0之间,损耗因子介于0.1~2.0之间。相关研究为颗粒状农产品的介电特性测量提供参考,实验数据为农产品的微波干燥和无损检测装置设计提供依据,技术方法适用于小颗粒物质的介电特性测量和分析。Dielectric properties are of important value in the application of microwave hot processing of agriculturalproducts. A scheme for measuring the dielectric properties of agricultural products based on uncelebrated coaxialtransmission reflection method and modified general effective medium formula ( MGEM) was proposed, in which thegranular agricultural products were taken as the research object. Dielectric property data of rapeseeds, coarse cerealsand grass seeds in the microwave frequency band were measured. Relevant key issues were then analyzed anddiscussed. These results demonstrated that the measurement scheme could be used to measure the dielectric propertiesof particulate agricultural products at high frequency, and the dielectric properties of granular agricultural productsunder the room temperature were related with microwave frequency and water (oil) content. Such relationship met thecorresponding relational equation. Given the microwave frequency 2.45 GHz for civil use and the water content M e(2%,25%) , the dielectric constant was between 3.5 and 9, and the loss factor was between 0.1 and 2. This studyprovided a reference method for measurement of dielectric properties of granular agricultural products, and the basisfor the design of microwave drying and nondestructive testing devices for agricultural products. The technologicalmethod was suitable to measurement and analysis of dielectric properties of other small granular substances.

关 键 词：颗粒状农产品 介电特性 测量 微波频段 

分 类 号：S129[农业科学—农业基础科学]