Microstrip Circular Sensor for Determination of Moisture Content

Abstract

A microstrip moisture sensor (MMS) was designed, printed on FR4 material sheet size 18×18 mm2. The objective behind designing the sensor was to calculate moisture content (MC) in basmati rice. It is simulated on CST software on three frequencies: 3.6 GHz, 5.6 GHz, and 8.5 GHz. Actual moisture content (AMC) was varied from 10.71% to 21.87% for five samples at different water content; PMC was calculated for five samples with the help of calibration equations in which R.C. was achieved from VNA Model No. N9925A. For each frequency and sample, three moisture contents at each frequency were obtained, whose mean was taken to obtain final PMC. For other samples the same procedure was followed. Therefore, PMC varied from 10.70% to 21.82%. As MRE value determined with the help of AMC and PMC. Hence, the lowest MRE was 0.12%. Its significance is that when the grains (basmati rice) are fully saturated (100%) then MC measured from sensor will be reduced by 0.12%, i.e., obtained MC from sensor will be 99.88%.