Adjustable effective electromechanical coupling of Lamb wave resonator using AlN/Sc0.096Al0.904N composite films

With the rapid development of fifth-generation communication technology, there are more and more 5G frequency bands and their bandwidths are different. Therefore, many researchers devote themselves to the study of resonators with adjustable electromechanical coupling coefficient. In this paper, we apply composite films to the Lamb wave resonator with a double-IDT configuration to achieve adjustable effective electromechanical coupling coefficient (Keff2) of the first symmetric mode. The experimental results show that the Keff2 is adjusted from 3.82% to 6.32% and the Δf is adjusted from 41MHz to 63MHz by using the AlN/Sc0.096Al0.904N composite films with different thickness ratios. This method may be an efficient way to adjust the bandwidth of the filter to meet the needs of different frequency bands.