Low-Loss Longitudinal Leaky SAW Filter with 1350 MHz Bandwidth on $\text{LiNbO}_{3}/\text{SiO}_{2}/\text{SiC}$ 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 76-GHz band. Based on the X -cut <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{LiNbO}_{3}/\text{SiO}_{2}/\text{SiC}$</tex> 3-layer substrate, the fabricated set of longitudinal leaky mode (LL-SAW) resonators exhibit operating frequencies ranged over the entire Wi-Fi 76-GHz spectrum (5.925-7.125 GHz) while maintaining low loss and spurious-free performance. A LL-SAW filter with a 3 dB passband spanning 5.863 to 7.213 GHz, a low minimum insertion loss (IL) of 1.5 dB, and a peak power of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{2 9}$</tex> dBm is demonstrated. In contrast, LL-SAW resonators based on the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{LiNbO}_{3}/\text{SiC}$</tex> 2-layer substrate exhibit either considerably higher loss or strong adjacent spurious modes, which would severely affect the passband responses of the filter.