Rancang Bangun Alat dan Pengukuran Nilai Dielektrik pada Kisaran Frekuensi Radio

Abstract

Dielectric properties indicate the ability of a system to stole, transmit and reflect electromagnetic wave energy. Recently, the utilization of the properlies in agriculture field tends to increase. For example, dielectric dIying of biological material is based on the product's ability to absOI'b eIecI.rotnagneI tridiation and convert it into heat. In addition, /ower energy application of the propetty can be utilized for non-destructive measurement of water content. For a more broad application, measurement of the property and the influencing factors is i~peM~. - The objectives of this experiment were to design an instrument for measuring dielectric properties in radio frequency range and to detennine the dielectric properties of white pepper. The instrument was designed based on Q-meter method, which consists of oScil/ator, LRC circuit and capacitance meter. At the LRC circuit, with L=3.543 pH, the designed instrument can be used within a frequency range of 8 MHz to 22 MHz, where the peak teSOIJance capacitance was ranged from 21,72 pF to 177.49 pF. Application of the instrument in measuring the dielectric properties of white pepper showed that the value was fluctuated at frequencies less than 12 MHz. Accordingly, it was concluded that the instrument is appOcabie . for measuring dielectric properties of biological materials at frequency range of 14 to 22 MHz. It was also found that dielectric properties of whiie pepper were higher at higher moisture content.