Dielectric Permittivity Measurements of Electronics Cooling Fluids

Abstract

High performance electronics often present heat management challenges which can, in some applications, be mitigated through the use of liquid cooling technologies. In this work, select 3M Novec and 3M Fluorinert dielectric fluids are investigated using open-ended coaxial probe, microstrip ring resonator, and microstrip transmission line measurements. Microstrip structures in air are used to extract the relative permittivity of these fluids from the measured effective permittivity. Microstrip structures in 3M fluids are simulated using the electromagnetic finite element solver ANSYS HFSS to match measured effective permittivity. An approximation of the frequency dependent relative permittivities and loss tangents are provided up to 50GHz for 3M Novec-649, Novec HFE-7100, and Fluorinert FC-72. The feasibility of using ring resonator structures to detect specific contaminants within these dielectric fluids is also explored.