Microfluidic Biosensor for Bioengineering: High-frequency Equivalent-Circuit Modeling of Interdigital Capacitor

Microwave biosensing is a rapidly growing field of bioengineering. The progress in micro- and nanotechnologies and the recent advances in microwave dielectric spectroscopy have allowed a rapid development in the miniaturization of high-frequency biosensors. There has therefore been intensive research during the last few years on investigating miniature microwave biosensors for liquid characterization. To contribute to the advancement of this challenging and stimulating field of research, the present contribution is devoted to the analysis of a microfluidic sensor based on a one-port coplanar interdigital capacitor (IDC). The high-frequency performance of the studied sensor is achieved by using the 3D finite-element method (FEM) by Ansoft's high frequency structure simulator (HFSS). The simulations are used for extracting and validating an equivalent-circuit model that can be further exploited for complex permittivity extraction of the material under test.