Manufacture of Planar Interdigitated Capacitive Sensor and RVE Model Validation

Capacitive sensors hold significant promise for biosensors in both gaseous and liquid environments, enabling the detection and monitoring of biochemical compounds through variations in sensor capacitance. This paper aims to manufacture a capacitive sensor and validate its Representative Volume Element (RVE) computational model, aiming to optimize the sensor in future work. The sensor was manufactured using Computerized Numerical Control (CNC) laser, employing a planar geometry with a 15-finger interdigitated capacitor and FR4 dielectric. The sensor capacitance value was measured in different mediums (air, water, ethanol, and various water-ethanol solutions) using a Vector Network Analyzer (VNA). The RVE model was adapted and simulated using Comsol Multiphysics software, validating its behavior and ability to accurately represent the sensor with an error margin below 10%. This study demonstrates the feasibility of using the RVE model to optimize capacitive sensors and highlights the importance of simulation software and techniques such as Finite Element Method (FEM) in biosensor development.