Tri-layered XBAR with SiO2 middle layer

XBARs enable the design of low-loss 5 GHz filters that meet the n79 Specification. Meanwhile, the device is fragile, and designers fight to achieve the desired power-handling levels. The temperature shifts of lithium niobate are high. Recently proposed periodically poled structures enhance device robustness and increase the relative passband width; however, they also inherit other drawbacks mentioned. Here, we propose a tri-layered XBAR structure with SiO2 as the middle layer, which is robust, has significantly better TCF, and is supposed to improve power handling capability radically.