Analyzes the effect of temperature on characteristics of crude oil permittivity sensor based on Interdigital Capacitors (IDCs)

This study aims to analyze the effect of temperature on characteristics of crude oil permittivity sensor based on interdigital capacitors (IDCs), including linearity, repeatability and hysteresis. IDCs have been fabricated using the DC Magnetron Sputtering method in three designs with different electrode materials and the same electrode configuration. The electrode materials used silver (Ag), copper (Cu) and molybdenum (Mo) deposited on a FR-4 PCB substrate with a thickness of 1μm. The electrode configuration each design is 15 mm electrode length, 0.5 mm electrode width, 0.5 mm electrode distance and 40 electrodes number. The crude oil was tested at a temperature range of 30 - 70°C. The measurement system uses a PM6303A automatic RCL Meter at a frequency of 1 kHz. The sensor linearity test results showed an increase in the sensitivity value of the IDCs Ag, Mo and Cu sensors when the temperature was more than 50°C. The repeatability sensor test results showed that IDCs made from Ag had the highest measurement precision with a value of %repeatability is 2.5%. The hysteresis test results showed that the design IDCs made from Ag have high stability at high and low temperatures.