Enhanced Performance of 16.8 GHz BAW Resonators Using Polarity-Inverted Piezoelectric Film Stack Architecture

Bulk acoustic wave (BAW) filters are essential components in RF communication, offering low loss, compact size, and high-power handling capability. However, traditional frequency scaling of resonators with a single-layer piezoelectric film for high-frequency applications necessitates film thickness reduction, resulting in the increased electrical loss and exacerbated power handling issues. This work employs a novel BAW resonator architecture featuring a polarity-inverted piezoelectric stack, enabling high-frequency operation while maintaining optimal film thickness, thereby preserving the inherent advantages of BAW technology. Finite element simulations confirm a 45.3% reduction in peak temperature for the polarity-inverted resonator versus its unipolar counterpart at 16.8 GHz under 30 dBm input power. Concurrently, electromagnetic modeling reveals an 88% enhancement in Qs for the proposed architecture. The fabricated polarity-inverted resonator achieves a Qmax of 186 and an electromechanical coupling coefficient $\left( {k_{eff}^2} \right)$ of 7.27%, demonstrating significant potential for next-generation 6G and satellite communication applications operating above 10 GHz.