An adaptive RF acoustic resonator contains tunable and switchable hybrid surface-bulk acoustic waves (SAW-BAW). The surface and bulk acoustic waves couple for the spectral sensing and configurable filtering. The acoustic resonator includes a piezoelectric or ferroelectric layer, such as a SLAIN layer, which is patterned into interdigital transducers, and an intermediate layer of AlGaN—GaN, which is built on a SiC substrate. The device is protected under a plastic packaging cap. An external tuning voltage applies on the acoustic resonator to generate the tunable frequency and bandwidth of the bulk and surface acoustic waves. An RF switch generates an electric field to suppress a residual polarization during acoustic resonator switching. The bulk acoustic wave excited in the piezoelectric or ferroelectric layer couples with the surface acoustic wave propagating in the intermediate layer. The Sc concentration in the ferroelectric layer exceeds 28%. The transducers are capped with Bragg reflectors made of multiple Al and W layers.