A permittivity characterization method by detuned ring-resonators for bulk materials up to 110 GHz

An accurate characterization of microwave materials is essential for reliable high frequency circuit design. This paper presents a measurement setup, which enables a quick and accurate determination of the relative permittivity of dielectric bulk materials up to 110 GHz. A ring-resonator is manufactured on a well characterized substrate dealing as reference resonator. The Material Under Test (MUT) is placed on top of the ring, which increases the effective permittivity and therefore introduces a shift of the resonance frequency of the resonator. Electromagnetic field simulations with different heights and relative permittivities of the MUT provide a lookup table for the measured resonance frequencies. The functionality of the proposed measurement setup is validated by measurement results of different MUTs.