A Novel Handheld Device for Intact Corn Ear Moisture Content Measurement

Fan, Lifeng; Chai, Zhi-Qiang; Wang, Yongqian; Wang, Ziyang; Zhao, Peng-Fei; Li, Jinhai; Zhou, Qiao; Qin, Xiao-Huang; Yao, Jie-Peng; Yan, Shixian; Wang, Zhongyi; Huang, Lan

doi:10.1109/tim.2020.2994603

Cited by 25 publications

(17 citation statements)

References 27 publications

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“…Even more convenient is the ability to take real-time measurements of ear moisture using hand-held moisture devices [ 171 , 172 ]. Figure 16 illustrates a double-ring sensing probe for non-destructive kernel moisture detection in intact corn ears [ 173 ]. The 160 MHz operating frequency of the active reflection bridge circuit provided a linear output of voltage with kernel permittivity and temperature.…”

Section: Sample Hierarchical Modeling Of Permittivitymentioning

confidence: 99%

Dielectric Measurement of Agricultural Grain Moisture—Theory and Applications

Jones

Sheng

2022

Sensors

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Moisture content is a critical variable for the harvesting, processing, storing and marketing of cereal grains, oilseeds and legumes. Efficient and accurate determination of grain moisture content even with advanced nondestructive techniques, remains a challenge due to complex water-retaining biological structures and hierarchical composition and geometry of grains that affect measurement interpretation and require specific grain-dependent calibration. We review (1) the primary factors affecting permittivity measurements used in practice for inferring moisture content in grains; (2) develop novel methods for estimating critical parameters for permittivity modeling including packing density, porosity, water binding surface area and water phase permittivity and (3) represent the permittivity of packs of grains using dielectric mixture theory as a function of moisture content applied to high moisture corn (as a model grain). Grain permittivity measurements are affected by their free and bound water contents, chemical composition, temperature, constituent shape, phase configuration and measurement frequency. A large fraction of grain water is bound exhibiting reduced permittivity compared to that of free water. The reduced mixture permittivity and attributed to hydrophilic surfaces in starches, proteins and other high surface area grain constituents. The hierarchal grain structure (i.e., kernel, starch grain, lamella, molecule) and the different constituents influence permittivity measurements due to their layering, geometry (i.e., kernel or starch grain), configuration and water-binding surface area. Dielectric mixture theory offers a physically-based approach for modeling permittivity of agricultural grains and similar granular media.

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Section: Sample Hierarchical Modeling Of Permittivitymentioning

confidence: 99%

Dielectric Measurement of Agricultural Grain Moisture—Theory and Applications

Jones

Sheng

2022

Sensors

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“…Measuring the amplitude and phase of the reflected voltage signal is another technique. The MC monitoring in [3], [4], [21], [37], [38], [42], and [43] was accomplished through measuring the input impedance. It should be noted that measuring impedance is also possible through S-parameters measurement.…”

Section: Impedance Methodsmentioning

confidence: 99%

“…It should be noted that measuring impedance is also possible through S-parameters measurement. However, in [3], [4], [21], [37], [38], [42], and [43], MC monitoring was achieved by direct measurement of voltage and impedance. In addition, using VNA is not favorable in some applications due to the relatively high cost.…”

Section: Impedance Methodsmentioning

confidence: 99%

“…The MC of the corn was determined using the measured phase of the reflection coefficient. The MC in the middle of the corn ear can be considered a suitable indicator for the total MC of the corn [4].…”

Section: A Grain MC Monitoring Sensorsmentioning

confidence: 99%

“…Due to the correlation between electrical properties of the grain and MC level [4], methods for monitoring MC were proposed, including monitoring variations in the Sparameters (i.e., return loss and insertion loss) [1], [2], [5]− [7], [14], [23]− [33], [20], dielectric constant [8]− [10], [11], [22], [34]− [36], and impedance (i.e., through reflected voltages) [4], [21], [37], [38]. These can be achieved by implementing coaxial probes [31]− [33], [35], [18], ring antennas [1], [21], [26], [37], [17], horn antennas [25], [27], [28], [30], [34], [39], waveguides [27], [28], [31], and microstrip patch antennas [24], [29], [36], [40]− [43], [15], [16], [20].…”

Section: Introductionmentioning

confidence: 99%

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A Comprehensive Review of Portable Microwave Sensors for Grains and Mineral Materials Moisture Content Monitoring

Javanbakht¹,

Xiao

Amaya

2021

IEEE Access

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In this paper, a comprehensive review of portable microwave sensors for monitoring moisture content (MC) is presented. MC monitoring is crucial in different industries, particularly food and farming. Microwave-based approaches for measuring the MC of the grains and mineral materials are studied. These approaches are categorized into three groups: S-parameters, dielectric constant, and impedance measurements. While these methods are interrelated, they have differences. The investigated methods use different microwave antenna sensors for MC monitoring, such as coaxial probes, horn antennas, loop antennas, microstrip patch antennas, and frequency selective surface (FSS) antenna. State-of-the-art microwave sensors were investigated thoroughly to clarify the current challenges and possible solutions of MC monitoring. A comparison between the investigated sensors was made to determine their advantages and disadvantages. According to the comparison, sensors operating above 10 GHz suffer from cross-interference. Moreover, microstrip patches can monitor a wide MC range as extensive as 60%. At the same time, the FSS sensor has the highest sensitivity with an error as low as 0.023% at X-band. Microstrip patch and FSS antennas can be printed directly on a flexible, low-loss, and lightweight material to monitor the grain MC. The flexibility, compactness, portability, ease of environment-friendly fabrication, and high sensitivity are among the criteria determining the most suitable microwave sensors for industrial and consumer MC monitoring applications.INDEX TERMS antenna, moisture, portable, printed, sensor.

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