Measurements of the complex permittivity of microwave circuit board substrates using split dielectric resonator and reentrant cavity techniques

The split dielectric resonator technique makes it possible to measure the real part of permittivity of isotropic materials for a very broad permittivity range and dielectric loss tangents in the range from 10⁻⁴ to 10⁻¹ with high accuracy. For uniaxially anisotropic materials, the split resonator method permits measurement of the permittivity and and the dielectric loss tangent in the plane parallel to the the sample bottoms. Additional measurements using re-entrant cavity enable determination of permittivity and the dielectric loss tangent perpendicular to this plane