Capacitance dependence of interdigital capacitor on amount and type of applied liquid

Abstract

In this paper design and fabrication of three types of interdigital capacitors are discussed, as well as influence of the liquid amount on their capacitance, and possibility of liquid type determination by using the fabricated structures. For faster and more reliable determination of capacitance in dependence of capacitor dimension and used substrate, a software tool called INDICON was developed. Capacitance of three structures fabricated in conventional PCB technology was determined by measuring S-parameters. Measurements were also performed by adding the exact amount of liquids on the capacitor surface. In addition, capacitance value in dependence of liquid amount is presented and possibility of applying this structure for detection of liquid amount is analyzed. Also, capacitance value in dependence of used liquid types was shown. For all measured and calculated values good agreement is achieved. © (2013) Trans Tech Publications.