Complex Permittivity Extraction of IC-Package Materials beyond 110 GHz by Band-Limited Waveguide-Cavity Measurements

In this work, an accurate method for extracting the frequency-dependent complex permittivity in frequency bands above 110 GHz using a resonant waveguide (WG) cavity is presented. Although the measurement information is band-limited and the first TE-mode cannot be measured, the method can dispense with this information in a two-stage measurement procedure. The information from a prior non-resonant, but still band-limited, measurement is used to assign resonance peaks occurring in the resonant measurement to the corresponding resonance modes. This enables the correct mapping of the respective TE-modes from the air-filled to MUT-filled WG cavity across different frequency bands, and subsequently extracting the complex permittivity from their comparison. To ensure distortion-free determination of the complex permittivity at multiple frequency points throughout the frequency band, the influence of WG cavity coupling on the determination of the resonant frequency and quality factor (Q) is compensated.