Power handling capability evaluation method for bulk acoustic wave filters

Abstract Bulk acoustic wave (BAW) filters have been widely deployed in consumer electronic devices for mobile communication systems owing to their excellent performance. However, effective methods for evaluating the power handling capability of BAW filters remain insufficiently developed. To address this issue, this work proposes a finite-element-based simulation and experimental validation approach incorporating acoustic-electromagnetic-thermal multiphysics coupling. Combined with a power handling criterion defined by a 1 dB degradation in insertion loss, the electrothermal response characteristics and power tolerance of BAW filters under high-power excitation are systematically investigated. Simulation results indicate that when the input power reaches 38 dBm, the insertion loss degrades by approximately 1 dB, accompanied by pronounced hotspot formation in the first pair of series resonators, where the peak temperature rises to 237 °C. Experimental measurements yield a power handling capability of 38.3 dBm for the fabricated filter. Notably, the breakdown locations observed under high-power operation are in good agreement with the simulated hotspot distribution, thereby validating the accuracy of the proposed model in power handling evaluation and failure prediction.