Resonator-Level Extraction in Ladder Acoustic Wave Filters From S-Parameters
Matthew Ou, Raafat R. Mansour · IEEE Transactions on Microwave Theory and Techniques · 2025
We present a systematic method for extracting individual resonator elements directly from S-parameters of ladder acoustic wave filters. The approach utilizes rational function approximation in conjunction with Foster and Cauer form expansions to isolate the poles and zeros associated with each resonator to enable resonator-level extraction of the filter. The proposed method extracts key acoustic resonator parameters, including resonant frequency, coupling coefficients, and the corresponding Butterworth–Van Dyke (BVD) model. Numerical examples demonstrate the effectiveness of the extraction method. The approach can facilitate rapid diagnostics of acoustic filters and supports a systematic framework for computer-aided tuning and compensation techniques to correct the performance of acoustic filters. The method is developed with the goal of enabling on-wafer computer-aided tuning and diagnostics for acoustic filters, which has not been addressed in existing extraction techniques.