High dielectrics in microwave cavities

This paper identifies three distinct types of losses associated with high dielectric materials in a rf electric field, specifically in a rectangular TE₁₀₂ microwave cavity. Various orientations of high dielectric structures relative to the electric field polarization have been studied using ansoft high frequency structure simulator (HFSS) (version 9.0, Pittsburgh, PA) and Computer Simulation Technology (CST) Microwave Studio (version 5.0, Wellesley Hills, MA). From the behavior of the electric fields inside high dielectrics in a rf field, the three forms of losses are quantified and their sum minimized by breaking up the sample into planar layers orientated perpendicular to the electric field and optimizing size. This work is important for electron paramagnetic resonance spectroscopy where the high dielectric material is frequently a spin-labeled protein sample in aqueous solution. Extension to Magnetic Resonance and other microwave applications are possible.