Low-Loss Longitudinal Leaky SAW Filter with 1350MHz Bandwidth on LiNbO₃/SiO₂/SiC Platform for Wi-Fi 7

This work aims to present a radio frequency (RF) front-end surface acoustic wave (SAW) filter solution for the Wi-Fi 7 6-GHz band. Based on the X-cut LiNbO₃/SiO₂/SiC 3-layer substrate, the fabricated set of longitudinal leaky mode (LL-SAW) resonators exhibit operating frequencies ranged over the entire Wi-Fi 7 6-GHz spectrum (5.925–7.125 GHz) while maintaining low loss and spurious-free performance. A LL-SAW filter with a 3dB passband spanning 5.863 to 7.213 GHz, a low minimum insertion loss (IL) of 1.5 dB, and a peak power of 29 dBm is demonstrated. In contrast, LL-SAW resonators based on the LiNbO₃/SiC 2-layer substrate exhibit either considerably higher loss or strong adjacent spurious modes, which would severely affect the passband responses of the filter.