Supplementary material

This supplemental material provides detailed derivations and analytical models based on temporal coupled-mode theory (CMT) for describing resonant scattering in a rectangular waveguide loaded with one or two coupled dielectric discs. We present analytical expressions for reflection and transmission coefficients in both single-disc and double-disc configurations. The CMT accounts for the effects of near-field and far-field coupling, as well as material absorption. Additionally, we describe the procedure for verifying the identity of the ceramic resonators through transmission measurements and include supporting experimental data.