Thermal Optimization of High-Power-Handling Bulk Acoustic Wave Filters via Acoustic-Electromagnetic-Thermal Multi-Physics Coupling Model

Bulk Acoustic Wave (BAW) filters are widely employed in consumer electronic devices within mobile communication systems due to their excellent performance. However, high-power input induces self-heating in BAW filters, thereby limiting their power handling capability. In this work, an acoustic-electromagnetic-thermal multi-physics coupling simulation method for BAW filters is proposed, and a power handling capability evaluation strategy is established, based on the criterion of 1 dB insertion loss degradation at the upper cutoff frequency of the passband. By optimizing the aspect ratio of the shape of the resonator’s active region and splitting resonators with high dissipated power density, the self-heating temperature of the resonator is reduced and the distribution of power dissipation is improved. Experimental results validate the accuracy of the proposed power handling capability evaluation strategy. After optimization, the BAW filter’s power handling capability increases from 30 dBm to 33 dBm. The effective mitigation of self-heating is attributed to the suppression of ohmic loss and the optimization of the dissipated power density distribution, thereby enhancing the filter’s power handling capability.