Low-cost portable dielectric spectrometer based on mini-vector network analyzer and open-ended coaxial probe technology  

作　　者：Zhuozhuo Zhu Xinhua Zhu Wenchuan Guo 

机构地区：[1]College of Mechanical and Electronic Engineering,Northwest A&F University,Yangling 712100,Shaanxi,China [2]School of Physics and Electronic Information,Yan'an University,Yan'an 716000,Shaanxi,China [3]Shaanxi Research Center of Agricultural Equipment Engineering Technology,Yangling 712100,Shaanxi,China [4]Key Laboratory of Agricultural Internet of Things,Ministry of Agriculture and Rural Affairs,Yangling 712100,Shaanxi,China [5]Shaanxi Key Laboratory of Agricultural Information Perception and Intelligent Service,Yangling 712100,Shaanxi,China

出　　处：《International Journal of Agricultural and Biological Engineering》2024年第3期166-172,共7页国际农业与生物工程学报（英文）

基　　金：financial support provided by the National Natural Science Foundation of China(Grant No.32172308);Startup Foundation for Doctors of Yan'an University(No.YDBK2022-79).

摘　　要：As a simple,fast,and non-destructive measuring technology,dielectric spectroscopy is usually used to analyze the dielectric properties of agricultural products and food,and then to predict the main components of materials.However,the large and expensive vector network analyzers(VNA)with expensive analysis software applied in measuring dielectric properties make research limited to the laboratory.To acquire dielectric spectra in situ,a model for solving relative complex permittivity was derived,and its performance was validated.Then,a low-cost portable dielectric spectrometer with a mini VNA,a Raspberry Pi,and a coaxial probe as core parts was developed over the frequency range of 100-3000 MHz.The stability and accuracy of the developed spectrometer were tested using milk and juice.The results indicated that the relative errors of the model were within±5%for dielectric constant(ε′)and loss factor(ε″).The coefficients of variation of measuredε′andε″by the developed spectrometer at 100-3000 MHz were less than 1%and 2%,respectively.Compared with the dielectric properties obtained by using a commercial dielectric measurement system,the relative errors of measuredε′andε″were within±3.4%and±6.0%,respectively.This study makes fast,non-destructive,and on-site food quality detection using dielectric spectra possible.

关 键 词：coaxial probe mini vector network analyzer LOW-COST PORTABLE dielectric spectrometer 

分 类 号：S237[农业科学—农业机械化工程]