The dielectric properties of litchi fruit were determined using the open-ended coaxial probe method. The measurements were performed in the frequency range from 0.5 to 20 GHz during 3 days of storage at room temperature (~ 24 °C). The dielectric properties increased with storage time. Additionally, measurements at different temperatures (24, 30, 40 and 50 °C) were determined. The dielectric constant (ε′) decreased with increasing temperature in a frequency range of 0.5–5 GHz; at higher frequencies, ε' increased with increasing temperature. The loss factor (ε″) value increased at frequencies higher than 2 GHz and decreased with increasing temperature. The results will be useful for further applications using microwaves, such as microwave-assisted drying, sensing of quality parameters, modeling, and heating to protect against molds or insects, among other applications.

中文翻译：

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微波频率下荔枝果实（Litchi chinensis Sonn）的介电特性。


采用开放式同轴探针法测定了荔枝果实的介电性能。测量是在室温（约 24 °C）下储存 3 天期间在 0.5 至 20 GHz 的频率范围内进行的。介电性能随着储存时间的增加而增加。此外，还确定了不同温度（24、30、40 和 50 °C）下的测量结果。在0.5-5 GHz频率范围内，介电常数（ ε ′）随着温度的升高而降低；在较高频率下， ε'随着温度的升高而增加。损耗因数 ( ε ” ) 值在频率高于 2 GHz 时增加，并随着温度的升高而降低。研究结果将有助于使用微波的进一步应用，例如微波辅助干燥、质量参数传感、建模和加热以防止霉菌或昆虫等应用。