Terahertz Broadband Characterization of Wafer-Level Packaging Materials Based on SIW Multimode Cavities

This paper characterizes the dielectric constant of wafer-level packaging material polyimide (PI) in the terahertz (THz) frequency range of $150-270 \mathrm{GHz}$ using substrate integrated waveguide (SIW) multimode cavity. By coupling energy into the SIW cavity via microstrip lines, the $\mathrm{TE}_{10 K}$ mode is excited inside the cavity. The SIW multimode cavity is properly designed for operating frequency and multimode measurement. The processing measurements are carried out, providing the measured S-parameter curves. This structure has great prospects for achieving broadband characterization of wafer-level packaging materials in the THz frequency band.