We propose a new parameter extraction method for advanced polysilicon emitter bipolar transistors. This method is based on the predetermination of equivalent circuit parameters using the analytical expressions of de-embedded Z parameters of these devices. These parameter values are used as initial values for the parameter extraction process using optimization. The entire device equivalent circuit, containing RF probe pad and interconnection circuit parameters extracted by test structures, is optimized to fit measured S parameters for eliminating deembedding errors due to the imperfection of pad and inter-connection test structures. The equivalent circuit determined by this method shows excellent agreement with the measured S parameters from 0.1 to 26.5 GHz.