In this paper we present an extended mode-matching model for a split-cylinder resonator involving <i>TE</i> and <i>TM</i> resonant modes. The new model enhances the known <i>TE</i><sub>0np</sub> mode-matching model by improving mode identification and distortion analysis and providing better frequency range coverage for relative permittivity estimation. In order to verify the new model, measured spectra of several substrate materials are analyzed and the estimation results are compared with those of the <i>TE</i><sub>0np</sub> mode-matching model.